The Effect of Plasma-Polymerized Cerium-Doped Hexamethyldisiloxane Film Thickness on Corrosion Protection of L-PBF AlSi10Mg

The Effect of Plasma-Polymerized Cerium-Doped Hexamethyldisiloxane Film Thickness on Corrosion Protection of L-PBF AlSi10Mg | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article The Effect of Plasma-Polymerized Cerium-Doped Hexamethyldisiloxane Film Thickness on Corrosion Protection of L-PBF AlSi10Mg Mirjam Spuller, Nina Kovač, Peter Rodič, Simon Chwatal, Mattia Cabrioli, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6792304/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 12 Dec, 2025 Read the published version in Monatshefte für Chemie - Chemical Monthly → Version 1 posted 4 You are reading this latest preprint version Abstract Laser powder bed fusion (L-PBF)-manufactured AlSi10Mg components exhibit localized microstructural inhomogeneities and high surface roughness, rendering them susceptible to corrosion. This study investigates the characteristics of cerium-doped plasma-polymerized hexamethyldisiloxane (ppHMDSO) thin films deposited via atmospheric pressure plasma deposition (APPD), with emphasis on the influence of film thickness, governed by the number of deposition cycles (1, 3, and 5) on corrosion protection performance. All films incorporated cerium predominantly as CeO₂ nanoparticles within the polysiloxane matrix, as confirmed by SEM/EDXS and FTIR analyses. Film thicknesses ranged from ∼400 nm to ∼1700 nm, increasing nearly linearly with deposition cycles. Electrochemical measurements and a six-week neutral salt spray test demonstrated that a critical film thickness of ~ 900 nm (3 deposition cycles) is necessary to ensure effective corrosion protection. Thinner film (∼400 nm) exhibited incomplete substrate coverage and insufficient protection, attributed to the underlying surface roughness and porosity of the polymer network. Increasing the thickness to ~ 1700 nm yielded only marginal improvements, indicating the limited protective benefit beyond the optimal thickness. This study highlights the importance of optimizing the deposition parameters to achieve a balance between film performance and material efficiency, and demonstrates a scalable approach for improving the corrosion resistance of L-PBF AlSi10Mg components. Organometallic compounds Silicon compounds Atmospheric pressure plasma deposition (APPD) Corrosion protective films Cerium salts Cerium oxide nanoparticles Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 1. Introduction AlSi10Mg is commonly manufactured by additive manufacturing (AM), such as laser powder bed fusion (L-PBF). This aluminum alloy exhibits high processability, low cost, and a high strength-to-weight ratio, which is derived from its beneficial microstructural features developed during processing. [ 1 – 3 ] However, corrosion of the alloy is a critical factor and the deposition of additional protective films/coatings is needed to protect the alloy in more corrosive environments. [ 4 – 7 ] Traditionally, chromate conversion coatings (CCC) are used as protective coatings for wrought and cast aluminum alloys. However, applying CCC involves using both trivalent and hexavalent chromium, which are highly toxic and carcinogenic. [ 8 – 10 ] Therefore, safer and more environmentally acceptable alternatives are necessary. Over the past few years, several coating and surface treatment approaches have been developed, including sol-gel coatings,[ 11 – 13 ] physical or chemical vapour deposition, [ 14 , 15 ] and coating processes using plasma, such as plasma electrolytic oxidation [ 16 ] and plasma deposition at low and atmospheric pressure. [ 17 – 21 ] In particular, atmospheric pressure plasma deposition (APPD) of organosilicon-based thin films has emerged as a promising approach in recent years. [ 17 – 19 , 22 , 23 ] APPD takes advantage of plasma polymerization (pp), where introducing organic precursors as vapour into the plasma zone generates charged and neutral molecular fragments and radicals that recombine on the surface beneath the plasma, forming a protective plasma polymer on various substrates, including additively manufactured aluminum alloys. The use of a movable plasma jet in the process enables tunable film thicknesses, which can be controlled by varying the deposition duration or the number of deposition cycles. [ 21 , 24 – 27 ] Due to its predominantly organic structure and high vapour pressure, HMDSO, a low-toxicity organosilicon compound, is a common precursor for plasma polymerization. In the process, HMDSO molecules are activated by the plasma energy, resulting in their dissociation into reactive species, such as (CH 3 )SiO, Si(CH 3 ) 3 , (CH 3 ) 3 SiOSi(CH 3 ) 2 , and CH 3 , which polymerize and deposit on the substrate, forming a ppHMDSO film (abbreviated as ppF). The ppHMDSO film properties can range from organic PDMS-like to inorganic SiO x -like character depending on the applied process parameters. Additionally, ppHMDSO is known for its high (barrier) corrosion protection. [ 17 , 28 – 31 ] Several studies have already provided a detailed characterization of the resulting films and examined the corrosion protection offered by conventionally manufactured metals and their alloys. Bour et al. [ 22 ] analyzed ppHMDSO films on galvanized steel deposited by atmospheric pressure dielectric barrier discharge (DBD). They primarily focused on the impact of various deposition modes and post-treatments on the chemical structure and corrosion protection properties. They also found that plasma post-treatment, could be further enhanced due to a higher inorganic content of the layer close to the outer surface. Lommatzsch et al. [ 19 ] described the exceptional high corrosion protection of ppHMDSO thin films deposited with a modified plasma jet system from Plasmatreat GmbH (Steinhagen, Germany) on AA2024T3. They demonstrated that ppHMDSO films lack a fully cross-linked SiO 2 network; however they pass a 96-hour neutral salt spray test. Boscher et al. [ 18 ] describe the development, characterization and corrosion protection effect of plasma-deposited HMDSO thin films on 8xxx aluminum foils using an atmospheric plasma DBD. They demonstrated that with increasing O 2 in the plasma gas, a denser and more inorganic SiOx-like film with higher Si-O cross-linking can be achieved. Another innovative aspect employed in this study is the introduction of aerosols generated from salt solutions – such as a water solution of cerium (Ce) salt, which enables doping with cerium oxide nanoparticles (CeO 2 NPs) into the ppHMDSO films. [ 21 , 32 – 34 ] As reported in [ 21 , 35 – 39 ], cerium can act in the film as an active and/or passive corrosion inhibitor contributing to enhanced corrosion protection. The present investigation is part of a broader study aimed at optimizing the corrosion protection of Ce-doped ppHMDSO films. The first part investigated the influence of different cerium concentrations of the aerosol and the incorporation of Ce within the films. [ 21 ] In this study, the focus was on a second parameter: the influence of the number of deposition cycles – and thus varying film thicknesses − on the corrosion protection, using a selected cerium concentration. Based on[ 21 ] a trend was observed where increasing Ce concentration enhances the protective performance of the film. Therefore, the highest technically realizable concentration (20 wt.% Ce in the aerosol) was selected to prepare samples. The results of the bare sample, labelled as BARE, and the sample labelled ppF3 have already been published in the study [ 21 ]. 2. Results and discussion 2.1. Initial surface state and roughness of the ground substrate The substrate surface topography (including grinding marks, scratches, and other irregularities such as pores and valleys) affects the quality of coverage and integrity of the coating. [ 40 , 41 ] The additively manufactured surface state and roughness of the mechanically ground AlSi10Mg substrates were characterized to determine the surface characteristics before film deposition and investigations of the corrosion protection properties of the various ppHMDSO films. Light optical micrographs reveal that the substrates exhibit grinding marks and scratches (Fig. 1 a). Detailed scanning electron microscope (SEM) imaging showed that randomly scratched surface, with scribes between 1−2 µm in width (Fig. 1 b). As shown in Fig. 1 c, optical surface profilometry confirmed, the retained notable roughness and surface irregularities after mechanical surface pretreatment. The average roughness values were determined as follows: R a = 0.198 ± 0.009 µm, R z = 2.209 ± 0.296 µm, and R q = 0.259 ± 0.005 µm. These values are in arrangements with the qualitative observations from the visual surface analysis. A maximum peak height of surface asperities ( R p ) was also observed, with a value of 1.706 ± 0.776 µm. Additional roughness values are provided in Table S1 , in the supplementary material. The results of the surface characterization reveal a complex topography, emphasizing the necessity of optimizing the protective film thickness to achieve uniform coverage and effective sealing of surface asperities. 2.2. Thin film characterization The characterizing the Ce-doped ppHMDSO thin films, including measuring their thickness, was performed using tactile surface profilometry on Si wafer substrates. This method assessed how varying deposition cycles affect the film thickness. Profilometry measurements revealed film thicknesses of 407 ± 10 nm for ppF1, 938 ± 52 nm for ppF3, and 1682 ± 45 nm for ppF5. A nearly linear relationship was observed between the film thickness and the number of deposition cycles performed during the APPD process (Fig. 2 ). This confirms that the thickness can be well controlled by the number of deposition cycles, up to at least 1700 nm. The average thickness growth rate was determined to be approximately 15 nm/s, corresponding to an areal deposition rate of 0.66 nm/(s cm²). Compared to other studies utilizing lowpressure plasma deposition or cold plasma deposition at atmospheric pressure, the deposition rate achieved in this study exceeds most of the previously published rates. [ 18 , 22 , 42 , 43 ] This is primarily due to the high efficiency of the thermal plasma. [ 44 , 45 ] The SEM investigations also revealed that the ppHMDSO matrix for ppF1, ppF3 and ppF5 is pinhole-free, which is a crucial prerequisite for efficient (barrier) corrosion protection. EDXS analysis of all the films on Si wafers indicated the characteristic organicinorganic nature of ppHMDSO, as, in addition to Si and O, a significant Ccontent (∼16 − 18 at.%) was detected − consistent with residual organic groups from the precursor. Calculated average values of the elements are presented in Table 1 . Additionally, EDXS analysis was performed on AlSi10Mg samples to assess the initial chemical composition prior to corrosion testing (Table 2 ). The determined concentrations reveal the thin thickness of the films since only a slight increase in Si can be observed for ppF3 and ppF5. However, the evident decrease in Al concentration confirms the presence of a film with increasing thickness covering the metal surface, which consequently reduces the Al signal. Table 1 Chemical composition given in atomic percentages of the films deposited on Si wafers, gained from EDXS Sample Si / at.% O / at.% C / at.% ppF1 48.0 ± 0.2 34.9 ± 0.3 17.1 ± 0.2 ppF3 59.6 ± 0.08 22.4 ± 0.2 18.0 ± 0.2 ppF5 51.6 ± 0.4 32.4 ± 0.2 16.0 ± 0.3 Table 2 Chemical composition in atomic percentages of the films deposited on AlSi10Mg substrates, gained from EDXS. Additionally, the chemical composition of the bare substrate was determined Sample Al / at.% C / at.% O / at.% Si / at.% BARE 58.9 28.6 4.3 8.2 ppF1 48.3 27.1 16.6 8.0 ppF3 39.1 20.7 29.0 11.2 ppF5 35.6 30.1 25.3 9.0 FTIR was performed to gain a more detailed understanding of the chemical structure of the thin films. Spectra in the range between 4000 cm −1 and 400 cm −1 of the bare AlSi10Mg, the HMDSO precursor and the representative spectrum of the Cedoped ppHMDSO film (ppF3) is shown in Fig. 4 . Table 3 lists the determined absorption bands. The enlarged section between 1500 and 500 cm −1 is presented in the insert for detailed information of the mainly observed spectra bands. The BARE, ppF3 and the HMDSO precursor data were previously published in [ 21 ], and the spectra of ppF1 and ppF5 are given in the supplementary material Fig. S1 . For all the investigated films, broad absorption bands between 3700 and 3000 cm −1 , which are assigned to the O−H stretching mode in silanol (Si−OH) functional groups, and the stretching vibration of Si−OH at 900 cm −1 , are observed. Furthermore, a minor band at ∼2100 cm −1 corresponds to the Si−H stretching mode (υ Si−H). [ 28 , 30 ] The organic nature of the films is confirmed by the absorption bands at 1410 cm −1 (δ C−H), 1280 cm −1 (υ C−H in Si−(CH 3 ) x (x=1−3) ), and 840 cm −1 (δ C−H in Si−(CH 3 ) 3 ). Additionally, a band at 800 cm −1 , which represents υ Si−C and ρ a CH 3 , with a shoulder at 780 cm −1 representing (δ C−H in Si(CH 3 ) 2 ). [ 23 , 30 ] Grill et al.[ 23 ] revealed that the bands between 1250–650 cm −1 are a superposition of several individual bands. The characteristic and broad absorption band of ppHMDSO films, originating from υ Si−O vibrations in Si−O−Si bonds, is strongly pronounced between 1000 and 1200 cm − 1 . Dependent on the predominant structural organization of the formed polysiloxane, both the shape and position of the Si−O−Si absorption band vary. A low-density “cage structure” of the formed polysiloxane is indicated by a Si–O–Si band centered at 1135 cm −1 . In contrast, a maximum at 1023 cm −1 reflects a densely packed, highly cross-linked “network structure” of the polysiloxane. An absorption maximum centered around 1063 cm −1 , corresponds to a less cross-linked but still networked structure. [ 23 , 47 ]. From the obtained spectra of the ppHMDSO films, alterations in the absorption band are observed with varying film thickness, indicating structural changes within the material dependent on the deposition cycles. While the absorption band of ppF1 appears broad with a maximum position at 1076 cm −1 , the band of ppF5 is characterized by a shaper profile and a shift of the maximum position to 1045 cm −1 . This shift suggests that a higher number of deposition cycles correlates with the formation of a more densely packed film structure due to the difference in thermal conductivity between the bare substrate and after the deposition of the first few layers of the film. However, portions of the less densely packed “cage structure” are present in all films. Another remarkable variation in the spectra can be observed regarding the absorption band of the stretching vibration of Si−OH at 900 cm −1 . ppF1 exhibits the highest absorbance, which may be attributed to the lower energy input and reduced probability for condensation reactions of Si−OH to Si−O−Si. [ 48 ] For ppF3 and ppF5, the reduced absorbance levels suggest a higher degree of Si−O−Si cross-linking, which is consistent with the shifting of the Si−O−Si band to lower wavenumbers. Furthermore, the decreased intensity of the absorbance bands between 850 and 500 cm −1 , corresponding to organic functional groups, additionally indicates a more densely packed polysiloxane structure and an enhanced barrier property of the film. Due to the second dominant absorption band, which results from an overlap of bending and rocking vibrations of Si−O−Si bonds between 550 and 400 cm −1 ,[ 23 , 49 ] the characteristic stretching vibration band of CeO 2 (υ Ce−O) at 450 cm −1 [ 50 ] cannot be detected. Table 3 FTIR absorption bands, observed in the spectra of the bare (BARE), and filmcovered AlSi10Mg samples with ppF3, as well as the liquid HMDSO precursor. (υ stretching, δ - bending, ρ - rocking) Assignment Bands (cm −1 ) References υ O−H in SiOH 3700 − 3000 [ 28 , 30 ] υ Si−H 2160 [ 30 ] δ C−H 1410 [ 23 , 30 ] υ C−H in Si−(CH 3 ) x (x=1−3) 1280 [ 23 , 30 ] υ Si−O in Si−O−Si 1000–1200 [ 23 , 30 , 47 ] “cage structure” of Si−O−Si 1135 cm −1 [ 23 ] “network structure” of Si−O−Si 1023 cm −1 [ 23 ] υ Si−OH 900 [ 28 ] δ C−H in Si−(CH 3 ) 3 840 [ 30 ] υ Si−C and ρ a CH 3 800 [ 23 ] δ C−H in Si(CH 3 ) 2 780 [ 30 ] ρ Si−O−Si and δ Si−O−Si 400–550 [ 23 , 49 ] υ Ce−O 450 [ 50 ] 2.3. Corrosion testing using potentiodynamic polarization measurements Electrochemical corrosion measurements (potentiodynamic polarization tests, PDP) were performed on ground AlSi10Mg samples with and without film after an immersion time of 1 hour to investigate the protective behavior of the films. While the PDP curves of the samples are presented in Fig. 5 , the corresponding electrochemical corrosion parameters determined from the Tafel analyses are depicted in Fig. 6 a and Fig. 6 b, and summarized in Table 4 . As evident from the curves, the AlSi10Mg without film (BARE) exhibits a relatively high corrosion current density (7.0 × 10 −7 A cm −2 ), indicating the low corrosion resistance of the additively manufactured alloy. The protective ability of the thinnest film, ppF1 (400 nm), is minimal due to its low thickness. Nevertheless, the curve of ppF1 shows a low passivation compared to the bare AlSi10Mg; however, it appears unstable with minimal scattering in the curve. Compared to the bare substrate and ppF1, a significant decrease in corrosion current density for samples with deposited films ppF3 (900 nm) and ppF5 (1700 nm) to 2.4 × 10 −9 and 6.3 × 10 −9 A cm −2 can be observed. Additionally, the passivation is pronounced and stable, representing the effective barrier protection of the thin ppHMDSO films. The increased Δ E values observed for ppF3 (0.16 V) and ppF5 (0.23 V), compared to ppF1 (0.26 V, although unstable) and the bare substrate (0.01 V), indicate the chemical and electrochemical stability of these films, as well as the enhanced corrosion protection provided by the AlSi10Mg sample. Table 4 Electrochemical corrosion parameters ( j corr , E corr , E bd , Δ E ) derived from the Tafel exploration of PDP curves shown in Fig. 5 Sample j corr´ (A cm −2 ) E corr (V) E bd (V) Δ E (V) bare 7.0 × 10 −7 −0.57 −0.56 0.01 ppF1 4.3 × 10 −7 −0.60 −0.34 * 0.26 * ppF3 2.4 × 10 −9 −0.83 −0.67 0.16 ppF5 3.6 × 10 −9 −0.58 −0.35 0.23 * Unstable passivation 2.4. Coating durability testing using a neutral salt spray test The barrier performance of the films under simulated real-world conditions relevant to potential industrial applications was evaluated using a neutral salt spray test (NSST) in accordance with ASTM B117 over a period of six weeks (∼1008 hours); detailed testing conditions are provided in Chap. 4.2. All three types of films were deposited onto ground L-PBF AlSi10Mg substrates (100 × 70 × 3 mm³) and subsequently exposed to the test environment. An AlSi10Mg sample without protective film was included in the test series for comparison. Photographs were taken before and after the NSST for optical comparison (Fig. 7 a and Fig. 7 b, respectively). After 6 weeks (∼1008 h) of exposure, the corrosion protection of the ppHMDSO films is evident, confirming the findings obtained from electrochemical corrosion tests. While the bare sample is fully corroded after 6 weeks, the metallic sheen of all samples with ppHMDSO films remains. Visual investigations and photo analyses, Fig. 7 c reveal that the sample with the thinnest film (ppF1) displays numerous isolated areas of localized corrosion. The corroded area was determined to be approximately 20% (Fig. 8 ). This indicates inferior corrosion resistance compared to ppF3 and ppF5, where the AlSi10Mg substrates remain predominantly intact, showing only marginal corrosion, affecting < 1% of the surface. Additionally, SEM analysis and EDXS were performed to study the corrosion process in more detail. Figure 9 representatively depict secondary electron micrographs of the tested samples. The associated surface element distributions measured by EDXS are shown in the stacked bar diagram in Fig. 10 , with the right columns (after) representing the atomic concentrations after testing, while the left columns (before), based on Table 2 , show the initial concentrations for each sample. In the micrograph in Fig. 9 a the fully corroded surface, covered with corrosion products, of the bare AlSi10Mg is visible. In comparison, Fig. 9 b shows the substrate covered with ppF1. The corrosion protection of the Ce-doped ppHMDSO is evident; however, especially at scratches localized corrosion and formation of corrosion products occurred. In comparison, Fig. 9 c and Fig. 9 d represent the sufficiently protected surface provided by ppF3 and ppF5, respectively. The elemental distributions further confirm the efficient corrosion protection provided by the films (Fig. 10 ). A significant decrease in Al concentration and a corresponding increase of O concentration − indicative for the formation of the typical corrosion products (Al 2 O 3 and Al(OH) 3 ) − were observed in the bare AlSi10Mg sample. In contrast, these changes were minimal in the sample covered with ppF1. For ppF3 and ppF5, only slight variations in the elemental distributions were detected, which are likely attributable to measurement variability. This supports the proposed protection mechanism, indicating that a 400 nmthick film is insufficient to fully cover the asperities and surface defects of the LPBF-manufactured and ground substrate, whereas a 900 nm-thick film provides adequate coverage and effective surface protection. A further increase in deposition cycles results in only marginal improvements in protection performance. 2.5. Influence of film thickness on corrosion protection performance Based on the findings, a schematic model was developed to illustrate the influence of ppHMDSO film thickness concerning the existing substrate roughness, as shown in Fig. 11 . Film characterization revealed that the APPD process of HMDSO, combined with a Ce-containing aerosol, results in the formation of a polysiloxane structure containing incorporated CeO 2 nanoparticles. It was determined that a single deposition cycle of the thermal plasma jet results in a film thickness of approximately 400 nm (ppHMDSO ppF1), which already provides corrosion protection of AlSi10Mg compared to the bare AlSi10Mg. However, potentiodynamic polarization measurements and a neutral salt spray test have revealed that the corrosion protection performance of the 400 nm thin film is limited. One reason for this is the existing substrate roughness, which is approximately 0.2 µm ( R a ) and 1.7 µm ( R p ), affecting the efficiency of the thin ppHMDSO film. VanEvery et al. [ 40 ] discussed that top-down film deposition using plasma jets on substrates with existing surface roughness may result in non-uniform film growth, where surface asperities lead to shadowing effects and incomplete coverage in recessed regions. Grimoldi et al. [ 41 ] also report an island-like growth mechanism of ppHMDSO, where fragments of the precursor tend to adsorb on energetically favorable sites of the rough substrate, such as step edges, asperities, or microstructural inhomogeneities, resulting in the formation of a spatially inconsistent film. Due to these deposition characteristics, combined with the relatively high roughness of the AlSi10Mg substrate, the film does not cover the entire surface and areas, especially at deeper asperities or defects, as the asperities shadow them. Therefore, corrosion occurs, especially in the uncovered valleys (Fig. 11 b). The Ce-doped ppHMDSO film ppF1 contains less densely packed “cage”-like structured regions within the film, as revealed in FTIR spectroscopy, which enables electrolyte (corrosion medium, NaCl (aq) ) to gradually penetrate the film, reducing the corrosion protection efficiency over time. Although it was found that CeO 2 NPs increase the density of the films [ 21 ], this effect is only slightly supportive due to the thin thickness. As illustrated in Fig. 11 c, after performing 3 deposition cycles, the resulting thickness of Ce-doped ppHMDSO film (ppF3) is sufficiently thick that the initially shadowed regions are overgrown, resulting in complete coverage of the AlSi10Mg substrate and sufficient corrosion protection over a long time. A further increase in film thickness beyond 900 nm, achieved by applying more than 3 deposition cycles (ppF5 with 5 deposition cycles, Fig. 11 d), resulted in only a slight improvement in the corrosion protection performance. This suggests that additional material of Ce-doped ppHMDSO does not significantly contribute to the improvement of the barrier properties, possibly due to the already full coverage of the metallic surface after 3 deposition cycles. It is noted that, despite the overall good performance of both ppF3 and ppF5, localized corrosion may still occur in isolated regions. This can be attributed to the relatively permeable ppHMDSO, exhibiting portions of a less densely packed “cage structure” of the siloxane matrix; however, such areas are scarce due to the doping with CeO 2 NPs. Since only CeO 2 NPs were detected in the studied films, and no apparent signs of active corrosion protection were observed in either the potentiodynamic polarization measurement or the neutral salt spray test, future work should focus on optimizing the doping strategy. This includes not only incorporating CeO 2 NPs to increase the film density but also introducing Ce 3+ and Ce 4+ ions to enable active corrosion inhibition mechanisms. [ 35 – 37 ] 3. Conclusions Ce-doped plasma polymerized hexamethyldisiloxane (ppHMDSO) thin films were successfully deposited onto laser powder bed fusion (L-PBF) AlSi10Mg substrates using a thermal atmospheric pressure plasma deposition (APPD) process. The relationship between the number of deposition cycles, resulting film thickness, and corrosion protection performance was systematically investigated. The results confirmed: A nearly linear relationship was observed between number of deposition cycles and film thickness, with the latter reaching 1700 nm after five cycles. The APPD process achieved a high areal deposition rate of 0.66 nm/(s·cm²), exceeding the rates reported for many conventional low-pressure plasma deposition techniques. Corrosion resistance improved significantly with increasing film thickness. Both potentiodynamic polarization tests and a six-week neutral salt spray test demonstrated that films with thicknesses of ≥ 900 nm (≥ 3 deposition cycles) provided effective barrier protection. Thinner films (400 nm, 1 cycle) were insufficient to achieve full surface coverage, resulting in localized corrosion attributed to substrate roughness and incomplete film growth. FTIR analysis revealed increased polysiloxane cross-linking and densification of the film with increasing thickness, correlating with enhanced corrosion protection performance. SEM/EDXS analyses confirmed the presence of CeO₂ nanoparticles within the films; however no evidence of active corrosion inhibition from ionic cerium species was observed. In conclusion, this study demonstrates the potential of plasma polymerization via APPD offers a scalable and environmentally acceptable approach for enhancing the corrosion resistance of L-PBF-manufactured AlSi10Mg components. Robust performance requires the optimization of film thickness, with a minimum of ∼900 nm recommended for effective protection. Future research should focus on incorporating reactive cerium species within the polysiloxane network to assess their potential in enabling active corrosion inhibition. 4. Experimental L-PBFmanufactured AlSi10Mg samples produced by f3nice, Piantedo, Italy, with dimensions of 50 × 50 × 3 mm³ and 100 × 70 × 3 mm³ were used as substrates. Samples were mechanically ground in the presence of water using the Struers Tegramin 30 machine. For surface preparation, a MD Molto plate was used in the first step and SiC paper with a grit P1200 was used. Before film deposition, the surface roughness of the bare substrates was measured using an optical profilometer (MicroProf300, FRT GmbH, Germany) equipped with a chromatic white light sensor. According to DIN ISO 4287, a measuring length of 4.8 mm with a measuring point spacing of 1 µm was chosen. The film deposition was performed using HMDSO ≥ 98% as a precursor and cerium(III) nitrate hexahydrate (99% trace metals basis), both from Merck Chemicals and Life Science GesmbH, Vienna, Austria. In parallel, Si wafer substrates (p-type, boron-doped, Active Business Company GmbH, Germany) were used for film characterization. These were fixed using a heat-resistant polyimide (Kapton®) tape on the deposition platform, providing the masking for film thickness measurements. An aerosol-assisted APPD setup, as presented in Fig. 12 a and Fig. S2 , was used for this study. Additionally, a thermal plasma jet (Type: IC3, INO Technologie GmbH, Austria), a dosing system to evaporate HMDSO (Sura Instruments STS 10.2, Germany), and an aerosol generator (ATM211, Topas GmbH, Germany) were utilized. The IC3 was operated with argon as a plasma gas (flow rate: 10 L/min) at 120 A. HMDSO was introduced to the plasma via external feeds at a flow rate of 50 mL/min. A solution of cerium nitrate hexahydrate (Ce(NO 3 ) 3 × 6H 2 O) and distilled water (20 wt.% of Ce) was prepared by stirring for 5 minutes and subsequently filled into the aerosol generator's vessel. A two-substance nozzle with a diameter of 1.1 mm was used to produce a Ce-containing aerosol. This was introduced into the plasma at an estimated flow rate of 0.0167 mL/min (≈ 0.0033 g Ce/min) via the internal feeds of the IC3. Consequently, an HMDSOtoaerosol ratio of 2989:1 in the plasma was realized. A meander scan of the plasma jet, as illustrated in Fig. 12 b, was conducted at a scanning speed of 100 mm/s and a height of 50 mm above the substrate to ensure uniform film deposition. Following each complete scan, the meander was offset by ± 5 mm, resulting in successive builds up of the film. One deposition cycle takes 21 seconds. Within this study, plasmapolymerized films with 1 (ppF1), 3 (ppF3), and 5 (ppF5) deposition cycles were deposited on AlSi10Mg and Si wafers, Fig. 12 c. As a reference, AlSi10Mg without a film (BARE) were utilized. Film deposition was conducted at ambient temperature, whereby the substrate temperature was not specifically controlled. 4.1. Film characterization Film characterization included thickness measurements, surface roughness measurements, profilometry, scanning electron microscopy (SEM), energydispersive X-ray spectroscopy (EDXS), and Fourier transform infrared (FTIR) spectroscopy. A tactile profilometer (Veeco Dektak 150) was used to measure the film thickness on the simultaneously coated Si wafer pieces (30 × 30 mm²). On the Si wafers substrates, SEM and EDXS analyses were performed to examine the surface morphology of the films and detect incorporated CeO 2 nanoparticles, which formed as a result of cerium ion oxidation during the APPD process. [ 21 , 51 ] A TESCAN VEGA3 scanning electron microscope, equipped with a heated tungsten filament and a 20 kV high-voltage supply, was utilized. EDXS were performed with an Oxford detector at 20 kV. FTIR spectroscopy was performed on film-covered AlSi10Mg samples to investigate the chemical structure of the films. A Shimadzu IRSpirit spectrometer in damped total internal reflection mode was used for this. Spectroscopy was performed in the range between 400 cm − 1 and 4000 cm − 1 . Shimadzu LabSolutions IR software v2.25 performed baseline correction, smoothing and normalization to the highest intensity band for each spectrum. 4.2. Corrosion Testing The corrosion resistance of AlSi10Mg samples with and without films was evaluated using potentiodynamic polarization (PDP) measurements and natural salt spray tests. PDP measurements were performed in 0.1 M NaCl solution at ambient temperature. For this purpose, a standard corrosion cell with a three-electrode setup (K0235 Flat Cell Kit, Ametek; Fig. S3 in the supplementary material) was employed. An AlSi10Mg0.3 substrate with an exposed surface area of 1.0 cm², a carbon rod, and a saturated Ag/AgCl electrode (E = 0.197 V vs. the standard hydrogen electrode) served as the working, counter, and reference electrode. An Autolab PGSTAT 204M potentiostat/galvanostat (Metrohm Autolab, Utrecht, Netherlands) controlled by Nova 2.1 software. Samples were stabilized for 1 hour under open-circuit conditions before measurement. PDP scans were performed at 1 mV/s from − 250 mV vs. E oc up to 1 V vs. Ag/AgCl, and each test was repeated three times. Electrochemical corrosion parameters ( E corr , j corr ) were determined via Tafel extrapolation, and the breakdown potential ( E bd ) was identified to calculate the difference in the potential Δ E = | E bd − E corr |. The NSST was conducted in an HKT 750 BASIC-LINE salt-spray chamber (KÖHLER, 0.750 m³ capacity) in accordance with the ASTM B117-23 standard. The test was conducted at a chamber temperature of 35 ± 1°C, and the NaCl solution (50 ± 1 g/L), pH-regulated using 0.1 M NaOH or HCl solutions, was sprayed at approximately 1 mL/hour. After six weeks (∼ 1008 hours), the samples were cleaned of salt deposits and loose corrosion products using a tab and distilled water. Photos of the samples were taken before and after the test for qualitative analyses. The percentage of the corroded area was determined by quantitative photo analysis using ImageJ software. Photos taken after the salt spray test were selected and converted to 8-bit images for the analyses. The corroded areas were selected from protected ones by defining an individual grey value threshold. The software calculated the percentage of the selected (corroded) areas. Images were saved after setting the threshold as black-and-white images. An average value was calculated after performing the quantitative photo analyses three times per sample. For detailed investigations of the salt-spray-tested samples, scanning electron microscopy (SEM) analyses were conducted using the TESCAN VEGA3 microscope. Moreover, EDXS chemical analysis was performed over an area of 4.5 × 3.0 mm 2 at the same locations as the previously acquired SE micrographs. The distributions of Al, O, C, and Si were normalized to 100 at.% and depicted as stacked column charts for concentration comparison before and after the NSST. Declarations Acknowledgements: Thanks go to Harald Parizek for conducting coating deposition and characterization experiments and to Roswitha Elter and Thomas Prethaler, who performed SEM/EDXS analysis. The authors also acknowledge the Slovenian Research and Innovation Agency (ARIS) for funding the bilateral project between Slovenia and Austria titled Atmospheric pressure plasma deposited coatings synthesis and characterization (grant No. BI-AT/24-24-017) and OeAD – Agency for Education and Internalisation, project WTZ – SI18/2023. Author Contributions: Conceptualization, M.S., N.K., P.R., J.M.L.; methodology, M.S., N.K., P.R., M.C. M.V.; validation, formal analysis, M.S., N.K.; data curation, M.S., N.K., P.R.; writing-original draft preparation, M.S., P.R., N.K.; writing-review and editing; N.K, P.R., R.K., W.W.; supervision, P.R., J.M.L.; funding acquisition, J.M.L., G.P., P.R. Funding: This work has been financed by Horizon Europe MIMOSA Project, G.A. Number: 101091826 under the Call HORIZON-CL4-2022-RESILIENCE-01, from the Slovenian Research and Innovation Agency: research core funding No. P1-0134 and OeAD – Agency for Education and Internationalization, project WTZ – SI18/2023. Data Availability Statement: Data are available on request. Conflicts of Interest: The authors declare no conflict of interest. All authors have read and agreed to the published version of the manuscript. References Gatto A, Cappelletti C, Defanti S, Fabbri F (2023) Metals 13:913 Cabrini M, Calignano F, Fino P, Lorenzi S, Lorusso M, Manfredi D, Testa C, Pastore T (2018) Materials (Basel) 11 Cabrini M, Lorenzi S, Pastore T, Pellegrini S, Manfredi D, Fino P, Biamino S, Badini C (2016) J Mater Process Technol 231:326–335 Zheng Y, Zhao Z, Xiong R, Ren G, Yao M, Liu W, Zang L (2024) Progress Nat Science: Mater Int 34:89–101 Lackner JM, Kaindl R, Schwan A, Meier B, Augl S, Gumus S, Hinterer A, Stummer M (2021) Jahrbuch - Oberflächentechnik 1–24 Fathi P, Rafieazad M, Duan X, Mohammadi M, Nasiri AM (2019) Corros Sci 157:126–145 Prashanth KG, Debalina B, Wang Z, Gostin PF, Gebert A, Calin M, Kühn U, Kamaraj M, Scudino S, Eckert J (2014) J Mater Res 29:2044–2054 Zhang X, van den Bos C, Sloof WG, Hovestad A, Terryn H, de Wit J (2005) Surf Coat Technol 199:92–104 Saha R, Nandi R, Saha B (2011) J Coord Chem 64:1782–1806 Tandon SK, Saxena DK, Gaur JS, Chandra SV (1978) Environ Res 15:90–99 Rodič P, Lekka M, Andreatta F, Fedrizzi L, Milošev I (2020) Prog Org Coat 147:105701 Hamulić D, Rodič P, Poberžnik M, Jereb M, Kovač J, Milošev I (2020) Coatings 10:172 Rodič P, Katić J, Korte D, Desimone P, Franko M, Ceré S, Metikoš-Huković M, Milošev I (2018) Metals 8:248 Sampath Kumar T, Vinoth Jebaraj A (2020) Materials Today: Proceedings 22:1479–1488 Zhang K, Wu J, Chu P, Ge Y, Zhao R, Li X (2015) Int J Electrochem Sci 10:6257–6272 Valentini F, Pezzato L, Dabalà M, Brunelli K (2023) J Mater Res Technol 27:3595–3609 Morent R, de Geyter N, van Vlierberghe S, Dubruel P, Leys C, Schacht E (2009) Surf Coat Technol 203:1366–1372 Boscher ND, Choquet P, Duday D, Verdier S (2010) Surf Coat Technol 205:2438–2448 Lommatzsch U, Ihde J (2009) Plasma Processes Polym 6:642–648 Török T, Urbán P, Lassú G (2015) Int J Corros Scale Inhib 4:116–124 Spuller M, Kovač N, Rodič P, Major L, Chwatal S, Cabrioli M, Vanazzi M, de Pasquale G, Lackner JM, Kaindl R, Waldhauser W (2025) Surf Coat Technol 506:132094 Bour J, Bardon J, Aubriet H, Del Frari D, Verheyde B, Dams R, Vangeneugden D, Ruch D (2008) Plasma Processes Polym 5:788–796 Grill A, Neumayer DA (2003) J Appl Phys 94:6697–6707 Merche D, Vandencasteele N, Reniers F (2012) Thin Solid Films 520:4219–4236 Thyen R, Weber A, Klages C-P (1997) Surf Coat Technol 97:426–434 Massines F, Sarra-Bournet C, Fanelli F, Naudé N, Gherardi N (2012) Plasma Processes Polym 9:1041–1073 Jones BJ, Anguilano L, Ojeda JJ (2011) Diam Relat Mater 20:1030–1035 Petit-Etienne C, Tatoulian M, Mabille I, Sutter E, Arefi-Khonsari F (2007) Plasma Processes Polym 4:S562–S567 Fanelli F, d'Agostino R, Fracassi F (2011) Plasma Processes Polym 8:932–941 Santos NM, Gonçalves TM, de Amorim J, Freire CM, Bortoleto JR, Durrant SF, Ribeiro RP, Cruz NC, Rangel EC (2017) Surf Coat Technol 311:127–137 Sonnenfeld A, Tun TM, Zajíčková L, Kozlov KV, Wagner H-E, Behnke JF, Hippler R (2001) Plasmas Polym 6:237–266 Castillo Martinez IA (2007) Study of CeO₂ synthesis from liquid precursors in a RF-inductively coupled plasma reactor. Thesis, McGill University Castillo Martinez IA (2003) Solution plasma synthesis of CeO₂-based powders for solid oxide fuel cell electrolytes from liquid precursors. Thesis, McGill University Oh S, Shim J, Seo D, Shim MJ, Han SC, Lee C, Nam Y (2022) Prog Org Coat 170:106998 Rodič P, Milošev I (2020) Studia UBB Chem 65:227–244 Rodič P, Milošev I (2019) Corros Sci 149:108–122 Rodič P, Lekka M, Andreatta F, Milošev I, Fedrizzi L (2021) Electrochim Acta 370:137664 Regula C, Lukasczyk T, Ihde J, Fladung T, Wilken R (2012) Prog Org Coat 74:734–738 González E, Stuhr R, Vega JM, García-Lecina E, Grande H-J, Leiza JR, Paulis M (2021) Polymers (Basel) 13 VanEvery K, Krane MJM, Trice RW, Wang H, Porter W, Besser M, Sordelet D, Ilavsky J, Almer J (2011) J Therm Spray Tech 20:817–828 Grimoldi E, Zanini S, Siliprandi RA, Riccardi C (2009) Eur Phys J D 54:165–172 Zhu X, Arefi-Khonsari F, Petit‐Etienne C, Tatoulian M (2005) Plasma Processes Polym 2:407–413 Gosar Ž, Đonlagić D, Pevec S, Gergič B, Mozetič M, Primc G, Vesel A, Zaplotnik R (2021) Coatings 11:1218 Fauchais P, Vardelle A, Denoirjean A (1997) Surf Coat Technol 97:66–78 Mostaghimi J, Boulos MI (2015) Plasma Chem Plasma Process 35:421–436 Gharehbaghi A (2012) Precipitation Study in a High Temperature Austenitic Stainless Steel. using Low Voltage Energy Dispersive X-ray Spectroscopy Wulf G, Mayer B, Lommatzsch U (2022) Plasma 5:44–59 Qu H, Bhattacharyya S, Ducheyne P (2017) In: Kirkpatrick CJ, Hutmacher DE, Grainger DW, Healy K, Ducheyne P (eds) Comprehensive biomaterials II. Elsevier, Amsterdam, Netherlands Phil Launer B (2013) Arkles In: Silicon Compounds: Silanes & Silicones Zamiri R, Ahangar HA, Kaushal A, Zakaria A, Zamiri G, Tobaldi D, Ferreira JMF (2015) PLoS ONE 10:e0122989 Soukup L, Hubička Z, Churpita A, Čada M, Pokorný P, Zemek J, Jurek K, Jastrabı́k L (2003) Surf Coat Technol 169–170:571–574 Supplementary Files graphicalabstract.jpg supplemental.docx Cite Share Download PDF Status: Published Journal Publication published 12 Dec, 2025 Read the published version in Monatshefte für Chemie - Chemical Monthly → Version 1 posted Reviewers agreed at journal 11 Jul, 2025 Reviewers invited by journal 23 Jun, 2025 Editor assigned by journal 02 Jun, 2025 First submitted to journal 31 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6792304","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":475290058,"identity":"7c622489-5587-4d16-8d1c-8d2ee6e4f582","order_by":0,"name":"Mirjam Spuller","email":"data:image/png;base64,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","orcid":"","institution":"Joanneum Research Forschungsgesellschaft mbH","correspondingAuthor":true,"prefix":"","firstName":"Mirjam","middleName":"","lastName":"Spuller","suffix":""},{"id":475290059,"identity":"9d5a57bd-842e-4d00-8f36-abc75d9600c8","order_by":1,"name":"Nina Kovač","email":"","orcid":"","institution":"Jozef Stefan Institute: Institut Jozef Stefan","correspondingAuthor":false,"prefix":"","firstName":"Nina","middleName":"","lastName":"Kovač","suffix":""},{"id":475290060,"identity":"6d7af79b-ab29-4f64-99f7-8d3cdc3f700f","order_by":2,"name":"Peter Rodič","email":"","orcid":"","institution":"Jozef Stefan Institute: Institut Jozef Stefan","correspondingAuthor":false,"prefix":"","firstName":"Peter","middleName":"","lastName":"Rodič","suffix":""},{"id":475290061,"identity":"d603772c-0f8d-451a-a35c-10ec9c60629b","order_by":3,"name":"Simon Chwatal","email":"","orcid":"","institution":"JOANNEUM RESEARCH: Joanneum Research Forschungsgesellschaft mbH","correspondingAuthor":false,"prefix":"","firstName":"Simon","middleName":"","lastName":"Chwatal","suffix":""},{"id":475290062,"identity":"ee100aef-c895-475b-8430-0584dcc900bb","order_by":4,"name":"Mattia Cabrioli","email":"","orcid":"","institution":"f3nice","correspondingAuthor":false,"prefix":"","firstName":"Mattia","middleName":"","lastName":"Cabrioli","suffix":""},{"id":475290063,"identity":"e47c60b4-be97-42fa-8eb1-1563a5586485","order_by":5,"name":"Matteo Vanazzi","email":"","orcid":"","institution":"f3nice","correspondingAuthor":false,"prefix":"","firstName":"Matteo","middleName":"","lastName":"Vanazzi","suffix":""},{"id":475290064,"identity":"2d6f567a-967d-4b39-841b-fd765e526c1d","order_by":6,"name":"Giorgio De Pasquale","email":"","orcid":"","institution":"Politecnico di Torino","correspondingAuthor":false,"prefix":"","firstName":"Giorgio","middleName":"","lastName":"De Pasquale","suffix":""},{"id":475290065,"identity":"0120a611-a683-4fd6-bb21-9d384ab5ebc2","order_by":7,"name":"Juergen M. Lackner","email":"","orcid":"","institution":"JOANNEUM RESEARCH: Joanneum Research Forschungsgesellschaft mbH","correspondingAuthor":false,"prefix":"","firstName":"Juergen","middleName":"M.","lastName":"Lackner","suffix":""},{"id":475290066,"identity":"6efd5b83-1469-4a04-9be5-74bff2e0f71d","order_by":8,"name":"Reinhard Kaindl","email":"","orcid":"","institution":"JOANNEUM RESEARCH: Joanneum Research Forschungsgesellschaft mbH","correspondingAuthor":false,"prefix":"","firstName":"Reinhard","middleName":"","lastName":"Kaindl","suffix":""},{"id":475290067,"identity":"c1784357-a6a5-42ba-801c-4764422e3e59","order_by":9,"name":"Wolfgang Waldhauser","email":"","orcid":"","institution":"JOANNEUM RESEARCH: Joanneum Research Forschungsgesellschaft mbH","correspondingAuthor":false,"prefix":"","firstName":"Wolfgang","middleName":"","lastName":"Waldhauser","suffix":""}],"badges":[],"createdAt":"2025-05-31 17:27:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6792304/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6792304/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00706-025-03408-3","type":"published","date":"2025-12-12T15:58:17+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":85399499,"identity":"23871112-42dd-499e-8dd8-7da37a8d74e0","added_by":"auto","created_at":"2025-06-25 11:41:52","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":536801,"visible":true,"origin":"","legend":"\u003cp\u003ea) Light optical microscope image and b) SEM images at two selected magnifications of the mechanically ground AlSi10Mg substrate c) Representative line profile of the roughness measurement on the mechanically ground AlSi10Mg substrate\u003c/p\u003e","description":"","filename":"Fig.1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/85bca24dc4d928017c592adf.jpg"},{"id":85399489,"identity":"74f02ba9-c1cc-44ed-af98-165072b5f199","added_by":"auto","created_at":"2025-06-25 11:41:52","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":123600,"visible":true,"origin":"","legend":"\u003cp\u003ea) Schematic representation of Ce-doped ppHMDSO films deposited on AlSi10Mg and Si wafer substrates after 1, 3, and 5 deposition cycles in the APPD process. In the scheme, the CeO2 NPs are represented as yellow dots. b) ppHMDSO film thickness deposited on the Si wafer versus the deposition cycles of the thermal plasma jet\u003c/p\u003e","description":"","filename":"Fig.2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/ec9d4d6224a97c26fabd9d5c.jpg"},{"id":85399501,"identity":"28c201b7-6ca2-4752-8dac-fda7b577fadc","added_by":"auto","created_at":"2025-06-25 11:41:52","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":165083,"visible":true,"origin":"","legend":"\u003cp\u003ea) and b) Representative micrographs gained from SEM and EDXS analyses of Ce‑doped ppHMDSO film (ppF3) on Si wafer. c) EDXS mapping (Si, C and O) of the surface area marked with a square in Fig. 3b\u003c/p\u003e","description":"","filename":"Fig.3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/de2a5aadfc6c89d05dd90c70.jpg"},{"id":85399491,"identity":"ef070c84-dac4-436f-9ee8-ec798d5cec78","added_by":"auto","created_at":"2025-06-25 11:41:52","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":168306,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative FTIR spectrum of ppHMDSO film ppF3, the bare (BARE) AlSi10Mg sample, and the liquid HMDSO precursor\u003c/p\u003e","description":"","filename":"Fig.4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/499c82c9fe39531e3ef27ee8.jpg"},{"id":85401023,"identity":"0667fa46-9c7b-43c6-a51f-addfd649d2bd","added_by":"auto","created_at":"2025-06-25 12:05:52","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":110109,"visible":true,"origin":"","legend":"\u003cp\u003ePotentiodynamic polarization (PDP) curves of the AlSi10Mg samples with deposited films ppF1, ppF3 and ppF5, compared to the bare AlSi10Mg substrate\u003c/p\u003e","description":"","filename":"Fig.5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/5c8d52f51c9778aa34c47cb7.jpg"},{"id":85399490,"identity":"79d11814-5430-46bc-a7d1-f9f987e9ed44","added_by":"auto","created_at":"2025-06-25 11:41:52","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":77521,"visible":true,"origin":"","legend":"\u003cp\u003eElectrochemical corrosion parameters determined from Tafel exploration of PDP curves in Fig. 5 plotted against the film thickness. a) Corrosion current density jcorr and (b) corrosion potential Ecorr (●), breakdown potential Ebd (○) and ΔE = ∣Ebd − Ecorr∣. *For ppF1 only an unstable passivation was observed\u003c/p\u003e","description":"","filename":"Fig.6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/06f156b753ca576cd9eaa211.jpg"},{"id":85399506,"identity":"8c72fec3-ec2a-4ac1-884c-68fd2a663ff7","added_by":"auto","created_at":"2025-06-25 11:41:53","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":314656,"visible":true,"origin":"","legend":"\u003cp\u003ePhotographs of the ground AlSi10Mg samples used for the neutral salt spray test (NSST); a) initial state before NSST, b) tested state after 6 weeks of NSST, and c) images from photo analysis of photos depicted in Fig. 7b using ImageJ\u003c/p\u003e","description":"","filename":"Fig.7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/a29969d8d51e6b04054a1953.jpg"},{"id":85399814,"identity":"173070e7-9c21-4db9-99ea-1b904c73cc88","added_by":"auto","created_at":"2025-06-25 11:49:52","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":53889,"visible":true,"origin":"","legend":"\u003cp\u003eQuantified corrosion damage of AlSi10Mg samples without any protection (BARE) and with ppHMDSO thin film (ppF1, ppF3, ppF5) after the 6-week neutral salt spray test. Photo analyses were performed using ImageJ on photographs presented in \u003cstrong\u003eFig. 7\u003c/strong\u003eb. 26\u003c/p\u003e","description":"","filename":"Fig.8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/4dd1deb2328b8ccd8c682a84.jpg"},{"id":85399524,"identity":"0bd56270-2989-4db4-875d-dc97bae5dca6","added_by":"auto","created_at":"2025-06-25 11:41:53","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":452933,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images taken from the samples after the 6-week neutral salt spray test. a) the surface of the bare AlSi10Mg is fully corroded, b) the sample protected with ppF1 shows localized corrosion, especially at the scratches. c) ppF3 and d) ppF5 enables enhanced corrosion protection. 27\u003c/p\u003e","description":"","filename":"Fig.9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/05a5c851b85377a4cb7f6dd4.jpg"},{"id":85399505,"identity":"493f7ab7-f23f-4445-bee8-f8e448523e8c","added_by":"auto","created_at":"2025-06-25 11:41:53","extension":"jpg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":188016,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the chemical composition of the bare AlSi10Mg samples and samples with Ce-doped ppHMDSO film, gained from EDXS before (\u003cstrong\u003eTable 2 Table 1\u003c/strong\u003e) and after the neutral salt spray test 28\u003c/p\u003e","description":"","filename":"Fig.10.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/8d6bd57746d8fcf350f0953f.jpg"},{"id":85399819,"identity":"87f09f7e-3ed4-483b-854b-d99dd108ac71","added_by":"auto","created_at":"2025-06-25 11:49:53","extension":"jpg","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":247021,"visible":true,"origin":"","legend":"\u003cp\u003e\u003ca href=\"#_Toc199606451\"\u003eSchematic model of the corrosion protection of ppHMDSO dependent on the film thickness influenced by the existing substrate roughness of ground L‑PBF-manufactured AlSi10Mg. a) A bare AlSi10Mg fully corrodes in 0.1 M NaCl solution. b) The thinnest Ce-doped ppHMDSO film, ppF1, with a thickness of only 400 nm (after a single deposition cycle), already provides corrosion protection; however, the film can cover only a relatively small portion of the surface due to its deposition characteristics and the substrate's high roughness. Therefore, corrosion products are formed, especially in the uncovered valleys. c) The Ce-doped ppHMDSO ppF3, with a film thickness of approximately 900\u0026nbsp;nm (3 deposition cycles), sufficiently protects the surface, as the film fully covers the substrate. d) A film thickness exceeding 900 nm (corresponding to more than 3 deposition cycles) only slightly improved corrosion protection. 32\u003c/a\u003e\u003c/p\u003e","description":"","filename":"Fig.11.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/e5ee3c265f2bf8a24799515d.jpg"},{"id":85401027,"identity":"df472eec-d785-4a5e-9d77-02c69fa27d2a","added_by":"auto","created_at":"2025-06-25 12:05:59","extension":"jpg","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":296249,"visible":true,"origin":"","legend":"\u003cp\u003ea) Deposition set up using aerosol-assisted atmospheric pressure plasma deposition (APPD). b) Schematic scan pattern of the plasma jet during one deposition cycle. c) Sample variation within this study\u003c/p\u003e","description":"","filename":"Fig.12.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/ffad4fbacb961dbe891fc2a8.jpg"},{"id":98244303,"identity":"d5a41775-02cf-45ff-b64b-de77c4cce157","added_by":"auto","created_at":"2025-12-15 16:14:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3652903,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/186ca2b0-bf66-45aa-84af-4fe083c2894f.pdf"},{"id":85399494,"identity":"568eb346-776d-464b-bc3a-abffc6e714d1","added_by":"auto","created_at":"2025-06-25 11:41:52","extension":"jpg","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":211362,"visible":true,"origin":"","legend":"","description":"","filename":"graphicalabstract.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/f25ffaa4d21d8a065f4e4f05.jpg"},{"id":85400767,"identity":"0b04e506-0b5c-4c96-abe2-004c018b0a19","added_by":"auto","created_at":"2025-06-25 11:57:52","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":1759304,"visible":true,"origin":"","legend":"","description":"","filename":"supplemental.docx","url":"https://assets-eu.researchsquare.com/files/rs-6792304/v1/96fae7ff1315d662db18cacb.docx"}],"financialInterests":"","formattedTitle":"The Effect of Plasma-Polymerized Cerium-Doped Hexamethyldisiloxane Film Thickness on Corrosion Protection of L-PBF AlSi10Mg","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eAlSi10Mg is commonly manufactured by additive manufacturing (AM), such as laser powder bed fusion (L-PBF). This aluminum alloy exhibits high processability, low cost, and a high strength-to-weight ratio, which is derived from its beneficial microstructural features developed during processing. [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] However, corrosion of the alloy is a critical factor and the deposition of additional protective films/coatings is needed to protect the alloy in more corrosive environments. [\u003cspan additionalcitationids=\"CR5 CR6\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eTraditionally, chromate conversion coatings (CCC) are used as protective coatings for wrought and cast aluminum alloys. However, applying CCC involves using both trivalent and hexavalent chromium, which are highly toxic and carcinogenic. [\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] Therefore, safer and more environmentally acceptable alternatives are necessary. Over the past few years, several coating and surface treatment approaches have been developed, including sol-gel coatings,[\u003cspan additionalcitationids=\"CR12\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] physical or chemical vapour deposition, [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] and coating processes using plasma, such as plasma electrolytic oxidation [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] and plasma deposition at low and atmospheric pressure. [\u003cspan additionalcitationids=\"CR18 CR19 CR20\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] In particular, atmospheric pressure plasma deposition (APPD) of organosilicon-based thin films has emerged as a promising approach in recent years. [\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] APPD takes advantage of plasma polymerization (pp), where introducing organic precursors as vapour into the plasma zone generates charged and neutral molecular fragments and radicals that recombine on the surface beneath the plasma, forming a protective plasma polymer on various substrates, including additively manufactured aluminum alloys. The use of a movable plasma jet in the process enables tunable film thicknesses, which can be controlled by varying the deposition duration or the number of deposition cycles. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan additionalcitationids=\"CR25 CR26\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eDue to its predominantly organic structure and high vapour pressure, HMDSO, a low-toxicity organosilicon compound, is a common precursor for plasma polymerization. In the process, HMDSO molecules are activated by the plasma energy, resulting in their dissociation into reactive species, such as (CH\u003csub\u003e3\u003c/sub\u003e)SiO, Si(CH\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e, (CH\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003eSiOSi(CH\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e, and CH\u003csub\u003e3\u003c/sub\u003e, which polymerize and deposit on the substrate, forming a ppHMDSO film (abbreviated as ppF). The ppHMDSO film properties can range from organic PDMS-like to inorganic SiO\u003csub\u003ex\u003c/sub\u003e-like character depending on the applied process parameters. Additionally, ppHMDSO is known for its high (barrier) corrosion protection. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan additionalcitationids=\"CR29 CR30\" citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eSeveral studies have already provided a detailed characterization of the resulting films and examined the corrosion protection offered by conventionally manufactured metals and their alloys. Bour et al. [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] analyzed ppHMDSO films on galvanized steel deposited by atmospheric pressure dielectric barrier discharge (DBD). They primarily focused on the impact of various deposition modes and post-treatments on the chemical structure and corrosion protection properties. They also found that plasma post-treatment, could be further enhanced due to a higher inorganic content of the layer close to the outer surface. Lommatzsch et al. [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] described the exceptional high corrosion protection of ppHMDSO thin films deposited with a modified plasma jet system from Plasmatreat GmbH (Steinhagen, Germany) on AA2024T3. They demonstrated that ppHMDSO films lack a fully cross-linked SiO\u003csub\u003e2\u003c/sub\u003e network; however they pass a 96-hour neutral salt spray test. Boscher et al. [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] describe the development, characterization and corrosion protection effect of plasma-deposited HMDSO thin films on 8xxx aluminum foils using an atmospheric plasma DBD. They demonstrated that with increasing O\u003csub\u003e2\u003c/sub\u003e in the plasma gas, a denser and more inorganic SiOx-like film with higher Si-O cross-linking can be achieved.\u003c/p\u003e \u003cp\u003eAnother innovative aspect employed in this study is the introduction of aerosols generated from salt solutions \u0026ndash; such as a water solution of cerium (Ce) salt, which enables doping with cerium oxide nanoparticles (CeO\u003csub\u003e2\u003c/sub\u003e NPs) into the ppHMDSO films. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan additionalcitationids=\"CR33\" citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e] As reported in [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan additionalcitationids=\"CR36 CR37 CR38\" citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e], cerium can act in the film as an active and/or passive corrosion inhibitor contributing to enhanced corrosion protection.\u003c/p\u003e \u003cp\u003eThe present investigation is part of a broader study aimed at optimizing the corrosion protection of Ce-doped ppHMDSO films. The first part investigated the influence of different cerium concentrations of the aerosol and the incorporation of Ce within the films. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] In this study, the focus was on a second parameter: the influence of the number of deposition cycles \u0026ndash; and thus varying film thicknesses \u0026minus; on the corrosion protection, using a selected cerium concentration. Based on[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] a trend was observed where increasing Ce concentration enhances the protective performance of the film. Therefore, the highest technically realizable concentration (20 wt.% Ce in the aerosol) was selected to prepare samples. The results of the bare sample, labelled as BARE, and the sample labelled ppF3 have already been published in the study [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e"},{"header":"2. Results and discussion","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Initial surface state and roughness of the ground substrate\u003c/h2\u003e \u003cp\u003eThe substrate surface topography (including grinding marks, scratches, and other irregularities such as pores and valleys) affects the quality of coverage and integrity of the coating. [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e] The additively manufactured surface state and roughness of the mechanically ground AlSi10Mg substrates were characterized to determine the surface characteristics before film deposition and investigations of the corrosion protection properties of the various ppHMDSO films. Light optical micrographs reveal that the substrates exhibit grinding marks and scratches (Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e1\u003c/span\u003ea). Detailed scanning electron microscope (SEM) imaging showed that randomly scratched surface, with scribes between 1\u0026minus;2 \u0026micro;m in width (Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e1\u003c/span\u003eb). As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e1\u003c/span\u003ec, optical surface profilometry confirmed, the retained notable roughness and surface irregularities after mechanical surface pretreatment. The average roughness values were determined as follows: \u003cem\u003eR\u003c/em\u003e\u003csub\u003ea\u003c/sub\u003e = 0.198\u0026thinsp;\u0026plusmn;\u0026thinsp;0.009 \u0026micro;m, \u003cem\u003eR\u003c/em\u003e\u003csub\u003ez\u003c/sub\u003e = 2.209\u0026thinsp;\u0026plusmn;\u0026thinsp;0.296 \u0026micro;m, and \u003cem\u003eR\u003c/em\u003e\u003csub\u003eq\u003c/sub\u003e = 0.259\u0026thinsp;\u0026plusmn;\u0026thinsp;0.005 \u0026micro;m. These values are in arrangements with the qualitative observations from the visual surface analysis. A maximum peak height of surface asperities (\u003cem\u003eR\u003c/em\u003e\u003csub\u003ep\u003c/sub\u003e) was also observed, with a value of 1.706\u0026thinsp;\u0026plusmn;\u0026thinsp;0.776 \u0026micro;m. Additional roughness values are provided in Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e, in the supplementary material.\u003c/p\u003e \u003cp\u003eThe results of the surface characterization reveal a complex topography, emphasizing the necessity of optimizing the protective film thickness to achieve uniform coverage and effective sealing of surface asperities.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Thin film characterization\u003c/h2\u003e \u003cp\u003eThe characterizing the Ce-doped ppHMDSO thin films, including measuring their thickness, was performed using tactile surface profilometry on Si wafer substrates. This method assessed how varying deposition cycles affect the film thickness. Profilometry measurements revealed film thicknesses of 407\u0026thinsp;\u0026plusmn;\u0026thinsp;10 nm for ppF1, 938\u0026thinsp;\u0026plusmn;\u0026thinsp;52 nm for ppF3, and 1682\u0026thinsp;\u0026plusmn;\u0026thinsp;45 nm for ppF5. A nearly linear relationship was observed between the film thickness and the number of deposition cycles performed during the APPD process (Fig.\u0026nbsp;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e2\u003c/span\u003e). This confirms that the thickness can be well controlled by the number of deposition cycles, up to at least 1700 nm. The average thickness growth rate was determined to be approximately 15 nm/s, corresponding to an areal deposition rate of 0.66 nm/(s cm\u0026sup2;). Compared to other studies utilizing lowpressure plasma deposition or cold plasma deposition at atmospheric pressure, the deposition rate achieved in this study exceeds most of the previously published rates. [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e] This is primarily due to the high efficiency of the thermal plasma. [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe SEM investigations also revealed that the ppHMDSO matrix for ppF1, ppF3 and ppF5 is pinhole-free, which is a crucial prerequisite for efficient (barrier) corrosion protection. EDXS analysis of all the films on Si wafers indicated the characteristic organicinorganic nature of ppHMDSO, as, in addition to Si and O, a significant Ccontent (\u0026sim;16 \u0026minus; 18 at.%) was detected \u0026minus; consistent with residual organic groups from the precursor. Calculated average values of the elements are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Additionally, EDXS analysis was performed on AlSi10Mg samples to assess the initial chemical composition prior to corrosion testing (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The determined concentrations reveal the thin thickness of the films since only a slight increase in Si can be observed for ppF3 and ppF5. However, the evident decrease in Al concentration confirms the presence of a film with increasing thickness covering the metal surface, which consequently reduces the Al signal.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eChemical composition given in atomic percentages of the films deposited on Si wafers, gained from EDXS\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSi / at.%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eO / at.%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eC / at.%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eppF1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e48.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e34.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e17.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eppF3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e59.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e22.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e18.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eppF5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e51.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e32.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e16.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eChemical composition in atomic percentages of the films deposited on AlSi10Mg substrates, gained from EDXS. Additionally, the chemical composition of the bare substrate was determined\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAl / at.%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eC / at.%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eO / at.%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSi / at.%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBARE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e58.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e28.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eppF1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e48.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e27.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e16.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eppF3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e39.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e20.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e29.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e11.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eppF5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e35.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e30.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e25.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e9.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFTIR was performed to gain a more detailed understanding of the chemical structure of the thin films. Spectra in the range between 4000 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e and 400 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e of the bare AlSi10Mg, the HMDSO precursor and the representative spectrum of the Cedoped ppHMDSO film (ppF3) is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig16\" class=\"InternalRef\"\u003e4\u003c/span\u003e. Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e lists the determined absorption bands. The enlarged section between 1500 and 500 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e is presented in the insert for detailed information of the mainly observed spectra bands. The BARE, ppF3 and the HMDSO precursor data were previously published in [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], and the spectra of ppF1 and ppF5 are given in the supplementary material Fig.\u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e. For all the investigated films, broad absorption bands between 3700 and 3000 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, which are assigned to the O\u0026minus;H stretching mode in silanol (Si\u0026minus;OH) functional groups, and the stretching vibration of Si\u0026minus;OH at 900 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, are observed. Furthermore, a minor band at \u0026sim;2100 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e corresponds to the Si\u0026minus;H stretching mode (υ Si\u0026minus;H). [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe organic nature of the films is confirmed by the absorption bands at 1410 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e (δ C\u0026minus;H), 1280 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e (υ C\u0026minus;H in Si\u0026minus;(CH\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003ex (x=1\u0026minus;3)\u003c/sub\u003e), and 840 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e (δ C\u0026minus;H in Si\u0026minus;(CH\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e). Additionally, a band at 800 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, which represents υ Si\u0026minus;C and ρ\u003csup\u003ea\u003c/sup\u003e CH\u003csub\u003e3\u003c/sub\u003e, with a shoulder at 780 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e representing (δ C\u0026minus;H in Si(CH\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e). [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eGrill et al.[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] revealed that the bands between 1250\u0026ndash;650 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e are a superposition of several individual bands. The characteristic and broad absorption band of ppHMDSO films, originating from υ Si\u0026minus;O vibrations in Si\u0026minus;O\u0026minus;Si bonds, is strongly pronounced between 1000 and 1200 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Dependent on the predominant structural organization of the formed polysiloxane, both the shape and position of the Si\u0026minus;O\u0026minus;Si absorption band vary. A low-density \u0026ldquo;cage structure\u0026rdquo; of the formed polysiloxane is indicated by a Si\u0026ndash;O\u0026ndash;Si band centered at 1135 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e. In contrast, a maximum at 1023 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e reflects a densely packed, highly cross-linked \u0026ldquo;network structure\u0026rdquo; of the polysiloxane. An absorption maximum centered around 1063 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, corresponds to a less cross-linked but still networked structure. [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]. From the obtained spectra of the ppHMDSO films, alterations in the absorption band are observed with varying film thickness, indicating structural changes within the material dependent on the deposition cycles. While the absorption band of ppF1 appears broad with a maximum position at 1076 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, the band of ppF5 is characterized by a shaper profile and a shift of the maximum position to 1045 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e. This shift suggests that a higher number of deposition cycles correlates with the formation of a more densely packed film structure due to the difference in thermal conductivity between the bare substrate and after the deposition of the first few layers of the film. However, portions of the less densely packed \u0026ldquo;cage structure\u0026rdquo; are present in all films.\u003c/p\u003e \u003cp\u003eAnother remarkable variation in the spectra can be observed regarding the absorption band of the stretching vibration of Si\u0026minus;OH at 900 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e. ppF1 exhibits the highest absorbance, which may be attributed to the lower energy input and reduced probability for condensation reactions of Si\u0026minus;OH to Si\u0026minus;O\u0026minus;Si. [\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e] For ppF3 and ppF5, the reduced absorbance levels suggest a higher degree of Si\u0026minus;O\u0026minus;Si cross-linking, which is consistent with the shifting of the Si\u0026minus;O\u0026minus;Si band to lower wavenumbers. Furthermore, the decreased intensity of the absorbance bands between 850 and 500 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, corresponding to organic functional groups, additionally indicates a more densely packed polysiloxane structure and an enhanced barrier property of the film.\u003c/p\u003e \u003cp\u003eDue to the second dominant absorption band, which results from an overlap of bending and rocking vibrations of Si\u0026minus;O\u0026minus;Si bonds between 550 and 400 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e,[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e] the characteristic stretching vibration band of CeO\u003csub\u003e2\u003c/sub\u003e (υ Ce\u0026minus;O) at 450 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e] cannot be detected.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eFTIR absorption bands, observed in the spectra of the bare (BARE), and filmcovered AlSi10Mg samples with ppF3, as well as the liquid HMDSO precursor. (υ stretching, δ - bending, ρ - rocking)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAssignment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBands (cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eReferences\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eυ O\u0026minus;H in SiOH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3700 \u0026minus; 3000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eυ Si\u0026minus;H\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2160\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eδ C\u0026minus;H\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1410\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eυ C\u0026minus;H in Si\u0026minus;(CH\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003ex\u0026nbsp;(x=1\u0026minus;3)\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1280\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eυ Si\u0026minus;O in Si\u0026minus;O\u0026minus;Si\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1000\u0026ndash;1200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ldquo;cage structure\u0026rdquo; of Si\u0026minus;O\u0026minus;Si\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1135 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ldquo;network structure\u0026rdquo; of Si\u0026minus;O\u0026minus;Si\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1023 cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eυ Si\u0026minus;OH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e900\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eδ C\u0026minus;H in Si\u0026minus;(CH\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e840\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eυ Si\u0026minus;C and ρ\u003csup\u003ea\u003c/sup\u003e\u0026nbsp;CH\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e800\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eδ C\u0026minus;H in Si(CH\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e780\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eρ Si\u0026minus;O\u0026minus;Si and δ Si\u0026minus;O\u0026minus;Si\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e400\u0026ndash;550\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eυ Ce\u0026minus;O\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e450\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Corrosion testing using potentiodynamic polarization measurements\u003c/h2\u003e \u003cp\u003eElectrochemical corrosion measurements (potentiodynamic polarization tests, PDP) were performed on ground AlSi10Mg samples with and without film after an immersion time of 1 hour to investigate the protective behavior of the films. While the PDP curves of the samples are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig17\" class=\"InternalRef\"\u003e5\u003c/span\u003e, the corresponding electrochemical corrosion parameters determined from the Tafel analyses are depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig18\" class=\"InternalRef\"\u003e6\u003c/span\u003ea and Fig.\u0026nbsp;\u003cspan refid=\"Fig18\" class=\"InternalRef\"\u003e6\u003c/span\u003eb, and summarized in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. As evident from the curves, the AlSi10Mg without film (BARE) exhibits a relatively high corrosion current density (7.0 \u0026times; 10\u003csup\u003e\u0026minus;7\u003c/sup\u003e A cm\u003csup\u003e\u0026minus;2\u003c/sup\u003e), indicating the low corrosion resistance of the additively manufactured alloy. The protective ability of the thinnest film, ppF1 (400 nm), is minimal due to its low thickness. Nevertheless, the curve of ppF1 shows a low passivation compared to the bare AlSi10Mg; however, it appears unstable with minimal scattering in the curve. Compared to the bare substrate and ppF1, a significant decrease in corrosion current density for samples with deposited films ppF3 (900 nm) and ppF5 (1700 nm) to 2.4 \u0026times; 10\u003csup\u003e\u0026minus;9\u003c/sup\u003e and 6.3 \u0026times; 10\u003csup\u003e\u0026minus;9\u003c/sup\u003e A cm\u003csup\u003e\u0026minus;2\u003c/sup\u003e can be observed. Additionally, the passivation is pronounced and stable, representing the effective barrier protection of the thin ppHMDSO films. The increased Δ\u003cem\u003eE\u003c/em\u003e values observed for ppF3 (0.16 V) and ppF5 (0.23 V), compared to ppF1 (0.26 V, although unstable) and the bare substrate (0.01 V), indicate the chemical and electrochemical stability of these films, as well as the enhanced corrosion protection provided by the AlSi10Mg sample.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eElectrochemical corrosion parameters (\u003cem\u003ej\u003c/em\u003e\u003csub\u003ecorr\u003c/sub\u003e, \u003cem\u003eE\u003c/em\u003e\u003csub\u003ecorr\u003c/sub\u003e, \u003cem\u003eE\u003c/em\u003e\u003csub\u003ebd\u003c/sub\u003e, Δ\u003cem\u003eE\u003c/em\u003e) derived from the Tafel exploration of PDP curves shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig17\" class=\"InternalRef\"\u003e5\u003c/span\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026times;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003ej\u003c/em\u003e\u003csub\u003ecorr\u0026acute;\u003c/sub\u003e(A cm\u003csup\u003e\u0026minus;2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eE\u003c/em\u003e\u003csub\u003ecorr\u003c/sub\u003e (V)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eE\u003c/em\u003e\u003csub\u003ebd\u003c/sub\u003e (V)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eΔ\u003cem\u003eE\u003c/em\u003e (V)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ebare\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c2\"\u003e \u003cp\u003e7.0 \u0026times; 10\u003csup\u003e\u0026minus;7\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u0026minus;0.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026minus;0.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eppF1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c2\"\u003e \u003cp\u003e4.3 \u0026times; 10\u003csup\u003e\u0026minus;7\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u0026minus;0.60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026minus;0.34\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.26\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eppF3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c2\"\u003e \u003cp\u003e2.4 \u0026times; 10\u003csup\u003e\u0026minus;9\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u0026minus;0.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026minus;0.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eppF5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c2\"\u003e \u003cp\u003e3.6 \u0026times; 10\u003csup\u003e\u0026minus;9\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u0026minus;0.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026minus;0.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.23\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003csup\u003e*\u003c/sup\u003e Unstable passivation\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Coating durability testing using a neutral salt spray test\u003c/h2\u003e \u003cp\u003eThe barrier performance of the films under simulated real-world conditions relevant to potential industrial applications was evaluated using a neutral salt spray test (NSST) in accordance with ASTM B117 over a period of six weeks (\u0026sim;1008 hours); detailed testing conditions are provided in Chap.\u0026nbsp;4.2. All three types of films were deposited onto ground L-PBF AlSi10Mg substrates (100 \u0026times; 70 \u0026times; 3 mm\u0026sup3;) and subsequently exposed to the test environment. An AlSi10Mg sample without protective film was included in the test series for comparison. Photographs were taken before and after the NSST for optical comparison (Fig.\u0026nbsp;\u003cspan refid=\"Fig19\" class=\"InternalRef\"\u003e7\u003c/span\u003ea and Fig.\u0026nbsp;\u003cspan refid=\"Fig19\" class=\"InternalRef\"\u003e7\u003c/span\u003eb, respectively). After 6 weeks (\u0026sim;1008 h) of exposure, the corrosion protection of the ppHMDSO films is evident, confirming the findings obtained from electrochemical corrosion tests. While the bare sample is fully corroded after 6 weeks, the metallic sheen of all samples with ppHMDSO films remains. Visual investigations and photo analyses, Fig.\u0026nbsp;\u003cspan refid=\"Fig19\" class=\"InternalRef\"\u003e7\u003c/span\u003ec reveal that the sample with the thinnest film (ppF1) displays numerous isolated areas of localized corrosion. The corroded area was determined to be approximately 20% (Fig.\u0026nbsp;\u003cspan refid=\"Fig20\" class=\"InternalRef\"\u003e8\u003c/span\u003e). This indicates inferior corrosion resistance compared to ppF3 and ppF5, where the AlSi10Mg substrates remain predominantly intact, showing only marginal corrosion, affecting \u0026lt; 1% of the surface. Additionally, SEM analysis and EDXS were performed to study the corrosion process in more detail. Figure\u0026nbsp;\u003cspan refid=\"Fig21\" class=\"InternalRef\"\u003e9\u003c/span\u003e representatively depict secondary electron micrographs of the tested samples. The associated surface element distributions measured by EDXS are shown in the stacked bar diagram in Fig.\u0026nbsp;\u003cspan refid=\"Fig22\" class=\"InternalRef\"\u003e10\u003c/span\u003e, with the right columns (after) representing the atomic concentrations after testing, while the left columns (before), based on Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, show the initial concentrations for each sample. In the micrograph in Fig.\u0026nbsp;\u003cspan refid=\"Fig21\" class=\"InternalRef\"\u003e9\u003c/span\u003ea the fully corroded surface, covered with corrosion products, of the bare AlSi10Mg is visible. In comparison, Fig.\u0026nbsp;\u003cspan refid=\"Fig21\" class=\"InternalRef\"\u003e9\u003c/span\u003eb shows the substrate covered with ppF1. The corrosion protection of the Ce-doped ppHMDSO is evident; however, especially at scratches localized corrosion and formation of corrosion products occurred. In comparison, Fig.\u0026nbsp;\u003cspan refid=\"Fig21\" class=\"InternalRef\"\u003e9\u003c/span\u003ec and Fig.\u0026nbsp;\u003cspan refid=\"Fig21\" class=\"InternalRef\"\u003e9\u003c/span\u003ed represent the sufficiently protected surface provided by ppF3 and ppF5, respectively. The elemental distributions further confirm the efficient corrosion protection provided by the films (Fig.\u0026nbsp;\u003cspan refid=\"Fig22\" class=\"InternalRef\"\u003e10\u003c/span\u003e). A significant decrease in Al concentration and a corresponding increase of O concentration \u0026minus; indicative for the formation of the typical corrosion products (Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e and Al(OH)\u003csub\u003e3\u003c/sub\u003e) \u0026minus; were observed in the bare AlSi10Mg sample. In contrast, these changes were minimal in the sample covered with ppF1. For ppF3 and ppF5, only slight variations in the elemental distributions were detected, which are likely attributable to measurement variability.\u003c/p\u003e \u003cp\u003eThis supports the proposed protection mechanism, indicating that a 400 nmthick film is insufficient to fully cover the asperities and surface defects of the LPBF-manufactured and ground substrate, whereas a 900 nm-thick film provides adequate coverage and effective surface protection. A further increase in deposition cycles results in only marginal improvements in protection performance.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Influence of film thickness on corrosion protection performance\u003c/h2\u003e \u003cp\u003eBased on the findings, a schematic model was developed to illustrate the influence of ppHMDSO film thickness concerning the existing substrate roughness, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig23\" class=\"InternalRef\"\u003e11\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eFilm characterization revealed that the APPD process of HMDSO, combined with a Ce-containing aerosol, results in the formation of a polysiloxane structure containing incorporated CeO\u003csub\u003e2\u003c/sub\u003e nanoparticles. It was determined that a single deposition cycle of the thermal plasma jet results in a film thickness of approximately 400 nm (ppHMDSO ppF1), which already provides corrosion protection of AlSi10Mg compared to the bare AlSi10Mg. However, potentiodynamic polarization measurements and a neutral salt spray test have revealed that the corrosion protection performance of the 400 nm thin film is limited. One reason for this is the existing substrate roughness, which is approximately 0.2 \u0026micro;m (\u003cem\u003eR\u003c/em\u003e\u003csub\u003ea\u003c/sub\u003e) and 1.7 \u0026micro;m (\u003cem\u003eR\u003c/em\u003e\u003csub\u003ep\u003c/sub\u003e), affecting the efficiency of the thin ppHMDSO film. VanEvery et al. [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e] discussed that top-down film deposition using plasma jets on substrates with existing surface roughness may result in non-uniform film growth, where surface asperities lead to shadowing effects and incomplete coverage in recessed regions. Grimoldi et al. [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e] also report an island-like growth mechanism of ppHMDSO, where fragments of the precursor tend to adsorb on energetically favorable sites of the rough substrate, such as step edges, asperities, or microstructural inhomogeneities, resulting in the formation of a spatially inconsistent film. Due to these deposition characteristics, combined with the relatively high roughness of the AlSi10Mg substrate, the film does not cover the entire surface and areas, especially at deeper asperities or defects, as the asperities shadow them. Therefore, corrosion occurs, especially in the uncovered valleys (Fig.\u0026nbsp;\u003cspan refid=\"Fig23\" class=\"InternalRef\"\u003e11\u003c/span\u003eb).\u003c/p\u003e \u003cp\u003eThe Ce-doped ppHMDSO film ppF1 contains less densely packed \u0026ldquo;cage\u0026rdquo;-like structured regions within the film, as revealed in FTIR spectroscopy, which enables electrolyte (corrosion medium, NaCl\u003csub\u003e(aq)\u003c/sub\u003e) to gradually penetrate the film, reducing the corrosion protection efficiency over time. Although it was found that CeO\u003csub\u003e2\u003c/sub\u003e NPs increase the density of the films [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], this effect is only slightly supportive due to the thin thickness.\u003c/p\u003e \u003cp\u003eAs illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig23\" class=\"InternalRef\"\u003e11\u003c/span\u003ec, after performing 3 deposition cycles, the resulting thickness of Ce-doped ppHMDSO film (ppF3) is sufficiently thick that the initially shadowed regions are overgrown, resulting in complete coverage of the AlSi10Mg substrate and sufficient corrosion protection over a long time. A further increase in film thickness beyond 900 nm, achieved by applying more than 3 deposition cycles (ppF5 with 5 deposition cycles, Fig.\u0026nbsp;\u003cspan refid=\"Fig23\" class=\"InternalRef\"\u003e11\u003c/span\u003ed), resulted in only a slight improvement in the corrosion protection performance. This suggests that additional material of Ce-doped ppHMDSO does not significantly contribute to the improvement of the barrier properties, possibly due to the already full coverage of the metallic surface after 3 deposition cycles. It is noted that, despite the overall good performance of both ppF3 and ppF5, localized corrosion may still occur in isolated regions. This can be attributed to the relatively permeable ppHMDSO, exhibiting portions of a less densely packed \u0026ldquo;cage structure\u0026rdquo; of the siloxane matrix; however, such areas are scarce due to the doping with CeO\u003csub\u003e2\u003c/sub\u003e NPs.\u003c/p\u003e \u003cp\u003eSince only CeO\u003csub\u003e2\u003c/sub\u003e NPs were detected in the studied films, and no apparent signs of active corrosion protection were observed in either the potentiodynamic polarization measurement or the neutral salt spray test, future work should focus on optimizing the doping strategy. This includes not only incorporating CeO\u003csub\u003e2\u003c/sub\u003e NPs to increase the film density but also introducing Ce\u003csup\u003e3+\u003c/sup\u003e and Ce\u003csup\u003e4+\u003c/sup\u003e ions to enable active corrosion inhibition mechanisms. [\u003cspan additionalcitationids=\"CR36\" citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"3. Conclusions","content":"\u003cp\u003eCe-doped plasma polymerized hexamethyldisiloxane (ppHMDSO) thin films were successfully deposited onto laser powder bed fusion (L-PBF) AlSi10Mg substrates using a thermal atmospheric pressure plasma deposition (APPD) process. The relationship between the number of deposition cycles, resulting film thickness, and corrosion protection performance was systematically investigated. The results confirmed:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eA nearly linear relationship was observed between number of deposition cycles and film thickness, with the latter reaching 1700 nm after five cycles.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe APPD process achieved a high areal deposition rate of 0.66 nm/(s\u0026middot;cm\u0026sup2;), exceeding the rates reported for many conventional low-pressure plasma deposition techniques.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eCorrosion resistance improved significantly with increasing film thickness. Both potentiodynamic polarization tests and a six-week neutral salt spray test demonstrated that films with thicknesses of \u0026ge;\u0026thinsp;900 nm (\u0026ge;\u0026thinsp;3 deposition cycles) provided effective barrier protection.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThinner films (400 nm, 1 cycle) were insufficient to achieve full surface coverage, resulting in localized corrosion attributed to substrate roughness and incomplete film growth.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFTIR analysis revealed increased polysiloxane cross-linking and densification of the film with increasing thickness, correlating with enhanced corrosion protection performance.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eSEM/EDXS analyses confirmed the presence of CeO₂ nanoparticles within the films; however no evidence of active corrosion inhibition from ionic cerium species was observed.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eIn conclusion, this study demonstrates the potential of plasma polymerization via APPD offers a scalable and environmentally acceptable approach for enhancing the corrosion resistance of L-PBF-manufactured AlSi10Mg components. Robust performance requires the optimization of film thickness, with a minimum of \u0026sim;900 nm recommended for effective protection. Future research should focus on incorporating reactive cerium species within the polysiloxane network to assess their potential in enabling active corrosion inhibition.\u003c/p\u003e"},{"header":"4. Experimental","content":"\u003cp\u003eL-PBFmanufactured AlSi10Mg samples produced by f3nice, Piantedo, Italy, with dimensions of 50 \u0026times; 50 \u0026times; 3 mm\u0026sup3; and 100 \u0026times; 70 \u0026times; 3 mm\u0026sup3; were used as substrates. Samples were mechanically ground in the presence of water using the Struers Tegramin 30 machine. For surface preparation, a MD Molto plate was used in the first step and SiC paper with a grit P1200 was used. Before film deposition, the surface roughness of the bare substrates was measured using an optical profilometer (MicroProf300, FRT GmbH, Germany) equipped with a chromatic white light sensor. According to DIN ISO 4287, a measuring length of 4.8 mm with a measuring point spacing of 1 \u0026micro;m was chosen.\u003c/p\u003e \u003cp\u003eThe film deposition was performed using HMDSO\u0026thinsp;\u0026ge;\u0026thinsp;98% as a precursor and cerium(III) nitrate hexahydrate (99% trace metals basis), both from Merck Chemicals and Life Science GesmbH, Vienna, Austria.\u003c/p\u003e \u003cp\u003eIn parallel, Si wafer substrates (p-type, boron-doped, Active Business Company GmbH, Germany) were used for film characterization. These were fixed using a heat-resistant polyimide (Kapton\u0026reg;) tape on the deposition platform, providing the masking for film thickness measurements.\u003c/p\u003e \u003cp\u003eAn aerosol-assisted APPD setup, as presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig24\" class=\"InternalRef\"\u003e12\u003c/span\u003ea and Fig. \u003cspan refid=\"MOESM2\" class=\"InternalRef\"\u003eS2\u003c/span\u003e, was used for this study. Additionally, a thermal plasma jet (Type: IC3, INO Technologie GmbH, Austria), a dosing system to evaporate HMDSO (Sura Instruments STS 10.2, Germany), and an aerosol generator (ATM211, Topas GmbH, Germany) were utilized. The IC3 was operated with argon as a plasma gas (flow rate: 10 L/min) at 120 A. HMDSO was introduced to the plasma via external feeds at a flow rate of 50 mL/min. A solution of cerium nitrate hexahydrate (Ce(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e \u0026times; 6H\u003csub\u003e2\u003c/sub\u003eO) and distilled water (20 wt.% of Ce) was prepared by stirring for 5 minutes and subsequently filled into the aerosol generator's vessel. A two-substance nozzle with a diameter of 1.1 mm was used to produce a Ce-containing aerosol. This was introduced into the plasma at an estimated flow rate of 0.0167 mL/min (\u0026asymp; 0.0033 g Ce/min) via the internal feeds of the IC3. Consequently, an HMDSOtoaerosol ratio of 2989:1 in the plasma was realized.\u003c/p\u003e \u003cp\u003eA meander scan of the plasma jet, as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig24\" class=\"InternalRef\"\u003e12\u003c/span\u003eb, was conducted at a scanning speed of 100 mm/s and a height of 50 mm above the substrate to ensure uniform film deposition. Following each complete scan, the meander was offset by \u0026plusmn;\u0026thinsp;5 mm, resulting in successive builds up of the film. One deposition cycle takes 21 seconds. Within this study, plasmapolymerized films with 1 (ppF1), 3 (ppF3), and 5 (ppF5) deposition cycles were deposited on AlSi10Mg and Si wafers, Fig.\u0026nbsp;\u003cspan refid=\"Fig24\" class=\"InternalRef\"\u003e12\u003c/span\u003ec. As a reference, AlSi10Mg without a film (BARE) were utilized. Film deposition was conducted at ambient temperature, whereby the substrate temperature was not specifically controlled.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e4.1. Film characterization\u003c/h2\u003e \u003cp\u003eFilm characterization included thickness measurements, surface roughness measurements, profilometry, scanning electron microscopy (SEM), energydispersive X-ray spectroscopy (EDXS), and Fourier transform infrared (FTIR) spectroscopy. A tactile profilometer (Veeco Dektak 150) was used to measure the film thickness on the simultaneously coated Si wafer pieces (30 \u0026times; 30 mm\u0026sup2;). On the Si wafers substrates, SEM and EDXS analyses were performed to examine the surface morphology of the films and detect incorporated CeO\u003csub\u003e2\u003c/sub\u003e nanoparticles, which formed as a result of cerium ion oxidation during the APPD process. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eA TESCAN VEGA3 scanning electron microscope, equipped with a heated tungsten filament and a 20 kV high-voltage supply, was utilized. EDXS were performed with an Oxford detector at 20 kV.\u003c/p\u003e \u003cp\u003eFTIR spectroscopy was performed on film-covered AlSi10Mg samples to investigate the chemical structure of the films. A Shimadzu IRSpirit spectrometer in damped total internal reflection mode was used for this. Spectroscopy was performed in the range between 400 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 4000 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. Shimadzu LabSolutions IR software v2.25 performed baseline correction, smoothing and normalization to the highest intensity band for each spectrum.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e4.2. Corrosion Testing\u003c/h2\u003e \u003cp\u003eThe corrosion resistance of AlSi10Mg samples with and without films was evaluated using potentiodynamic polarization (PDP) measurements and natural salt spray tests. PDP measurements were performed in 0.1 M NaCl solution at ambient temperature. For this purpose, a standard corrosion cell with a three-electrode setup (K0235 Flat Cell Kit, Ametek; Fig. S3 in the supplementary material) was employed. An AlSi10Mg0.3 substrate with an exposed surface area of 1.0 cm\u0026sup2;, a carbon rod, and a saturated Ag/AgCl electrode (E\u0026thinsp;=\u0026thinsp;0.197 V vs. the standard hydrogen electrode) served as the working, counter, and reference electrode. An Autolab PGSTAT 204M potentiostat/galvanostat (Metrohm Autolab, Utrecht, Netherlands) controlled by Nova 2.1 software. Samples were stabilized for 1 hour under open-circuit conditions before measurement. PDP scans were performed at 1 mV/s from \u0026minus;\u0026thinsp;250 mV vs. \u003cem\u003eE\u003c/em\u003e\u003csub\u003eoc\u003c/sub\u003e up to 1 V vs. Ag/AgCl, and each test was repeated three times. Electrochemical corrosion parameters (\u003cem\u003eE\u003c/em\u003e\u003csub\u003ecorr\u003c/sub\u003e, \u003cem\u003ej\u003c/em\u003e\u003csub\u003ecorr\u003c/sub\u003e) were determined via Tafel extrapolation, and the breakdown potential (\u003cem\u003eE\u003c/em\u003e\u003csub\u003ebd\u003c/sub\u003e) was identified to calculate the difference in the potential Δ\u003cem\u003eE\u003c/em\u003e = |\u003cem\u003eE\u003c/em\u003e\u003csub\u003ebd\u003c/sub\u003e \u0026minus; \u003cem\u003eE\u003c/em\u003e\u003csub\u003ecorr\u003c/sub\u003e|.\u003c/p\u003e \u003cp\u003eThe NSST was conducted in an HKT 750 BASIC-LINE salt-spray chamber (K\u0026Ouml;HLER, 0.750 m\u0026sup3; capacity) in accordance with the ASTM B117-23 standard. The test was conducted at a chamber temperature of 35\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u0026deg;C, and the NaCl solution (50\u0026thinsp;\u0026plusmn;\u0026thinsp;1 g/L), pH-regulated using 0.1 M NaOH or HCl solutions, was sprayed at approximately 1 mL/hour. After six weeks (\u0026sim; 1008 hours), the samples were cleaned of salt deposits and loose corrosion products using a tab and distilled water. Photos of the samples were taken before and after the test for qualitative analyses. The percentage of the corroded area was determined by quantitative photo analysis using ImageJ software. Photos taken after the salt spray test were selected and converted to 8-bit images for the analyses. The corroded areas were selected from protected ones by defining an individual grey value threshold. The software calculated the percentage of the selected (corroded) areas. Images were saved after setting the threshold as black-and-white images. An average value was calculated after performing the quantitative photo analyses three times per sample.\u003c/p\u003e \u003cp\u003eFor detailed investigations of the salt-spray-tested samples, scanning electron microscopy (SEM) analyses were conducted using the TESCAN VEGA3 microscope. Moreover, EDXS chemical analysis was performed over an area of 4.5 \u0026times; 3.0 mm\u003csup\u003e2\u003c/sup\u003e at the same locations as the previously acquired SE micrographs. The distributions of Al, O, C, and Si were normalized to 100 at.% and depicted as stacked column charts for concentration comparison before and after the NSST.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements:\u0026nbsp;\u003c/strong\u003eThanks go to Harald Parizek for conducting coating deposition and characterization experiments and to Roswitha Elter and Thomas Prethaler, who performed SEM/EDXS analysis. The authors also acknowledge the Slovenian Research and Innovation Agency (ARIS) for funding the bilateral project between Slovenia and Austria titled Atmospheric pressure plasma deposited coatings synthesis and characterization (grant No. BI-AT/24-24-017) and OeAD \u0026ndash; Agency for Education and Internalisation, project WTZ \u0026ndash; SI18/2023.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions:\u003c/strong\u003e Conceptualization, M.S., N.K., P.R., J.M.L.; methodology, M.S., N.K., P.R., M.C. M.V.; validation, formal analysis, M.S., N.K.; data curation, M.S., N.K., P.R.; writing-original draft preparation, M.S., P.R., N.K.; writing-review and editing; N.K, P.R., R.K., W.W.; supervision, P.R., J.M.L.; funding acquisition, J.M.L., G.P., P.R.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e This work has been financed by Horizon Europe MIMOSA Project, G.A. Number: 101091826 under the Call HORIZON-CL4-2022-RESILIENCE-01, from the Slovenian Research and Innovation Agency: research core funding No. P1-0134 and OeAD \u0026ndash; Agency for Education and Internationalization, project WTZ \u0026ndash; SI18/2023.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement:\u003c/strong\u003e Data are available on request.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of Interest:\u003c/strong\u003e The authors declare no conflict of interest. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eGatto A, Cappelletti C, Defanti S, Fabbri F (2023) Metals 13:913\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCabrini M, Calignano F, Fino P, Lorenzi S, Lorusso M, Manfredi D, Testa C, Pastore T (2018) Materials (Basel) 11\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCabrini M, Lorenzi S, Pastore T, Pellegrini S, Manfredi D, Fino P, Biamino S, Badini C (2016) J Mater Process Technol 231:326\u0026ndash;335\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZheng Y, Zhao Z, Xiong R, Ren G, Yao M, Liu W, Zang L (2024) Progress Nat Science: Mater Int 34:89\u0026ndash;101\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLackner JM, Kaindl R, Schwan A, Meier B, Augl S, Gumus S, Hinterer A, Stummer M (2021) Jahrbuch - Oberfl\u0026auml;chentechnik 1\u0026ndash;24\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFathi P, Rafieazad M, Duan X, Mohammadi M, Nasiri AM (2019) Corros Sci 157:126\u0026ndash;145\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePrashanth KG, Debalina B, Wang Z, Gostin PF, Gebert A, Calin M, K\u0026uuml;hn U, Kamaraj M, Scudino S, Eckert J (2014) J Mater Res 29:2044\u0026ndash;2054\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang X, van den Bos C, Sloof WG, Hovestad A, Terryn H, de Wit J (2005) Surf Coat Technol 199:92\u0026ndash;104\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSaha R, Nandi R, Saha B (2011) J Coord Chem 64:1782\u0026ndash;1806\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTandon SK, Saxena DK, Gaur JS, Chandra SV (1978) Environ Res 15:90\u0026ndash;99\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRodič P, Lekka M, Andreatta F, Fedrizzi L, Milošev I (2020) Prog Org Coat 147:105701\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHamulić D, Rodič P, Poberžnik M, Jereb M, Kovač J, Milošev I (2020) Coatings 10:172\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRodič P, Katić J, Korte D, Desimone P, Franko M, Cer\u0026eacute; S, Metikoš-Huković M, Milošev I (2018) Metals 8:248\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSampath Kumar T, Vinoth Jebaraj A (2020) Materials Today: Proceedings 22:1479\u0026ndash;1488\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang K, Wu J, Chu P, Ge Y, Zhao R, Li X (2015) Int J Electrochem Sci 10:6257\u0026ndash;6272\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eValentini F, Pezzato L, Dabal\u0026agrave; M, Brunelli K (2023) J Mater Res Technol 27:3595\u0026ndash;3609\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMorent R, de Geyter N, van Vlierberghe S, Dubruel P, Leys C, Schacht E (2009) Surf Coat Technol 203:1366\u0026ndash;1372\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoscher ND, Choquet P, Duday D, Verdier S (2010) Surf Coat Technol 205:2438\u0026ndash;2448\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLommatzsch U, Ihde J (2009) Plasma Processes Polym 6:642\u0026ndash;648\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eT\u0026ouml;r\u0026ouml;k T, Urb\u0026aacute;n P, Lass\u0026uacute; G (2015) Int J Corros Scale Inhib 4:116\u0026ndash;124\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSpuller M, Kovač N, Rodič P, Major L, Chwatal S, Cabrioli M, Vanazzi M, de Pasquale G, Lackner JM, Kaindl R, Waldhauser W (2025) Surf Coat Technol 506:132094\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBour J, Bardon J, Aubriet H, Del Frari D, Verheyde B, Dams R, Vangeneugden D, Ruch D (2008) Plasma Processes Polym 5:788\u0026ndash;796\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrill A, Neumayer DA (2003) J Appl Phys 94:6697\u0026ndash;6707\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMerche D, Vandencasteele N, Reniers F (2012) Thin Solid Films 520:4219\u0026ndash;4236\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThyen R, Weber A, Klages C-P (1997) Surf Coat Technol 97:426\u0026ndash;434\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMassines F, Sarra-Bournet C, Fanelli F, Naud\u0026eacute; N, Gherardi N (2012) Plasma Processes Polym 9:1041\u0026ndash;1073\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJones BJ, Anguilano L, Ojeda JJ (2011) Diam Relat Mater 20:1030\u0026ndash;1035\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePetit-Etienne C, Tatoulian M, Mabille I, Sutter E, Arefi-Khonsari F (2007) Plasma Processes Polym 4:S562\u0026ndash;S567\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFanelli F, d'Agostino R, Fracassi F (2011) Plasma Processes Polym 8:932\u0026ndash;941\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSantos NM, Gon\u0026ccedil;alves TM, de Amorim J, Freire CM, Bortoleto JR, Durrant SF, Ribeiro RP, Cruz NC, Rangel EC (2017) Surf Coat Technol 311:127\u0026ndash;137\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSonnenfeld A, Tun TM, Zaj\u0026iacute;čkov\u0026aacute; L, Kozlov KV, Wagner H-E, Behnke JF, Hippler R (2001) Plasmas Polym 6:237\u0026ndash;266\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCastillo Martinez IA (2007) Study of CeO₂ synthesis from liquid precursors in a RF-inductively coupled plasma reactor. Thesis, McGill University\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCastillo Martinez IA (2003) Solution plasma synthesis of CeO₂-based powders for solid oxide fuel cell electrolytes from liquid precursors. Thesis, McGill University\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOh S, Shim J, Seo D, Shim MJ, Han SC, Lee C, Nam Y (2022) Prog Org Coat 170:106998\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRodič P, Milošev I (2020) Studia UBB Chem 65:227\u0026ndash;244\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRodič P, Milošev I (2019) Corros Sci 149:108\u0026ndash;122\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRodič P, Lekka M, Andreatta F, Milošev I, Fedrizzi L (2021) Electrochim Acta 370:137664\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRegula C, Lukasczyk T, Ihde J, Fladung T, Wilken R (2012) Prog Org Coat 74:734\u0026ndash;738\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGonz\u0026aacute;lez E, Stuhr R, Vega JM, Garc\u0026iacute;a-Lecina E, Grande H-J, Leiza JR, Paulis M (2021) Polymers (Basel) 13\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVanEvery K, Krane MJM, Trice RW, Wang H, Porter W, Besser M, Sordelet D, Ilavsky J, Almer J (2011) J Therm Spray Tech 20:817\u0026ndash;828\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrimoldi E, Zanini S, Siliprandi RA, Riccardi C (2009) Eur Phys J D 54:165\u0026ndash;172\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhu X, Arefi-Khonsari F, Petit‐Etienne C, Tatoulian M (2005) Plasma Processes Polym 2:407\u0026ndash;413\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGosar Ž, Đonlagić D, Pevec S, Gergič B, Mozetič M, Primc G, Vesel A, Zaplotnik R (2021) Coatings 11:1218\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFauchais P, Vardelle A, Denoirjean A (1997) Surf Coat Technol 97:66\u0026ndash;78\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMostaghimi J, Boulos MI (2015) Plasma Chem Plasma Process 35:421\u0026ndash;436\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGharehbaghi A (2012) Precipitation Study in a High Temperature Austenitic Stainless Steel. using Low Voltage Energy Dispersive X-ray Spectroscopy\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWulf G, Mayer B, Lommatzsch U (2022) Plasma 5:44\u0026ndash;59\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQu H, Bhattacharyya S, Ducheyne P (2017) In: Kirkpatrick CJ, Hutmacher DE, Grainger DW, Healy K, Ducheyne P (eds) Comprehensive biomaterials II. Elsevier, Amsterdam, Netherlands\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePhil Launer B (2013) Arkles In: Silicon Compounds: Silanes \u0026amp; Silicones\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZamiri R, Ahangar HA, Kaushal A, Zakaria A, Zamiri G, Tobaldi D, Ferreira JMF (2015) PLoS ONE 10:e0122989\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSoukup L, Hubička Z, Churpita A, Čada M, Pokorn\u0026yacute; P, Zemek J, Jurek K, Jastrabı́k L (2003) Surf Coat Technol 169\u0026ndash;170:571\u0026ndash;574\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"monatshefte-fur-chemie-chemical-monthly","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"mccm","sideBox":"Learn more about [Monatshefte für Chemie - Chemical Monthly](https://www.springer.com/journal/706)","snPcode":"706","submissionUrl":"https://www.editorialmanager.com/mccm/","title":"Monatshefte für Chemie - Chemical Monthly","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Organometallic compounds, Silicon compounds, Atmospheric pressure plasma deposition (APPD), Corrosion protective films, Cerium salts, Cerium oxide nanoparticles","lastPublishedDoi":"10.21203/rs.3.rs-6792304/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6792304/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eLaser powder bed fusion (L-PBF)-manufactured AlSi10Mg components exhibit localized microstructural inhomogeneities and high surface roughness, rendering them susceptible to corrosion. This study investigates the characteristics of cerium-doped plasma-polymerized hexamethyldisiloxane (ppHMDSO) thin films deposited via atmospheric pressure plasma deposition (APPD), with emphasis on the influence of film thickness, governed by the number of deposition cycles (1, 3, and 5) on corrosion protection performance. All films incorporated cerium predominantly as CeO₂ nanoparticles within the polysiloxane matrix, as confirmed by SEM/EDXS and FTIR analyses. Film thicknesses ranged from \u0026sim;400 nm to \u0026sim;1700 nm, increasing nearly linearly with deposition cycles. Electrochemical measurements and a six-week neutral salt spray test demonstrated that a critical film thickness of ~\u0026thinsp;900 nm (3 deposition cycles) is necessary to ensure effective corrosion protection. Thinner film (\u0026sim;400 nm) exhibited incomplete substrate coverage and insufficient protection, attributed to the underlying surface roughness and porosity of the polymer network. Increasing the thickness to ~\u0026thinsp;1700 nm yielded only marginal improvements, indicating the limited protective benefit beyond the optimal thickness. This study highlights the importance of optimizing the deposition parameters to achieve a balance between film performance and material efficiency, and demonstrates a scalable approach for improving the corrosion resistance of L-PBF AlSi10Mg components.\u003c/p\u003e","manuscriptTitle":"The Effect of Plasma-Polymerized Cerium-Doped Hexamethyldisiloxane Film Thickness on Corrosion Protection of L-PBF AlSi10Mg","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-25 11:41:47","doi":"10.21203/rs.3.rs-6792304/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2025-07-11T09:53:30+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-23T15:49:21+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-02T07:54:45+00:00","index":"","fulltext":""},{"type":"submitted","content":"Monatshefte für Chemie - Chemical Monthly","date":"2025-05-31T13:27:19+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"monatshefte-fur-chemie-chemical-monthly","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"mccm","sideBox":"Learn more about [Monatshefte für Chemie - Chemical Monthly](https://www.springer.com/journal/706)","snPcode":"706","submissionUrl":"https://www.editorialmanager.com/mccm/","title":"Monatshefte für Chemie - Chemical Monthly","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"4e67ab71-4ca5-4f17-8491-7d771e88565d","owner":[],"postedDate":"June 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-15T16:07:25+00:00","versionOfRecord":{"articleIdentity":"rs-6792304","link":"https://doi.org/10.1007/s00706-025-03408-3","journal":{"identity":"monatshefte-fur-chemie-chemical-monthly","isVorOnly":false,"title":"Monatshefte für Chemie - Chemical Monthly"},"publishedOn":"2025-12-12 15:58:17","publishedOnDateReadable":"December 12th, 2025"},"versionCreatedAt":"2025-06-25 11:41:47","video":"","vorDoi":"10.1007/s00706-025-03408-3","vorDoiUrl":"https://doi.org/10.1007/s00706-025-03408-3","workflowStages":[]},"version":"v1","identity":"rs-6792304","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6792304","identity":"rs-6792304","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}