The enhanced cohesive performance of magnetron sputtered Cr coatings on steel substrate via controlling columnar grain structures

The enhanced cohesive performance of magnetron sputtered Cr coatings on steel substrate via controlling columnar grain structures | 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 Article The enhanced cohesive performance of magnetron sputtered Cr coatings on steel substrate via controlling columnar grain structures Sitian Zhu, Wenxin Liu, Zhigang Xu, Xuehao Geng, Chuanbin Wang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7263123/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract This study investigates the effect of columnar grain structure on the cohesion of chromium (Cr) coatings, which is crucial for preventing cracking and enhancing durability. Cr coatings with varying columnar grain structures were prepared by adjusting magnetron sputtering deposition time. The relationship between grain structure, surface roughness, residual stress, and cohesion was examined. XRD results showed that all Cr coatings exhibited preferred orientations along the (211) plane. As deposition time increased, both grain size and coating thickness grew, leading to higher surface roughness and reduced residual stress, which in turn affected coating cohesion. The peak cohesion of 21.8 N was achieved when the grain size reached 690 nm and the coating thickness was 8.5 µm. Excessive residual stress and high surface roughness promoted crack formation, reducing cohesion. This study highlights the importance of controlling coating surface roughness and residual stress to enhance cohesion and provides valuable insights for developing advanced hard coatings. Columnar grain structures Residual stress Cohesion strength Magnetron sputtering Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 1 Introduction Stainless steel (SS304) is widely used in extreme environment applications such as mechanical engineering, marine, medical and aerospace[ 1 – 3 ]. To prolong the life and durability of stainless steel components, high performance protective coatings are often applied to the surface[ 4 ]. Among these coatings, chromium (Cr) coatings have been extensively researched and utilized to enhance the mechanical performance of engineered components due to their exceptional physical and chemical properties, including low friction coefficient, excellent corrosion resistance, high oxidation resistance, and improved thermal stability[ 5 – 9 ]. Moreover, Cr is abundant, has a high ionization rate, boasts excellent production efficiency, and is notably cost - effective[ 10 , 11 ]. Currently, magnetron sputtering (MS) is one of the most common methods for preparing Cr coatings, as it has attracted much attention from researchers due to its environmental friendliness, non-pollution, and the smooth surface of the prepared coatings[ 12 ]. Although the research on MS Cr coatings has a long history and their composition, structure, and properties have been extensively explored, significant challenges remain. Numerous studies have shown that MS Cr coatings often suffer from issues such as low adhesion or cracking, which prevent the full realization of their excellent properties and ultimately affect the long-term protection of the substrate[ 13 – 15 ]. In fact, the adhesion between a coating and a substrate can be divided into two components: the coating's own cohesive force and the interfacial bonding force between the coating and the substrate. However, most studies on improvement strategies have focused on interfacial bonding force[ 16 – 19 ], often ignoring the effect of the columnar grain structure of magnetron-sputtered coatings on coating cohesion, especially with regard to the size of coating surface particles and coating thickness. Clarifying the intrinsic relationship between columnar grain structure and coating cohesion is of significant theoretical and practical importance for optimizing coating design at the microstructural level and substantially enhancing coating cohesion. In this study, Cr coatings with varying columnar grain structures were deposited on SS304 substrates by adjusting the deposition time during the magnetron sputtering process. A systematic investigation was conducted to assess the impact of deposition time on the columnar grain structures, surface roughness, residual stress, and cohesive strength of Cr coatings. The relationship between coating columnar grain structures, residual stress, and coating cohesion was established, providing valuable data to support the enhancement of cohesion in thick Cr coatings. 2 Experimental procedures 2.1 Coating preparation DC magnetron sputtering (PD-400C, Pudi Vacuum Equipment Company, China) was utilized to deposit Cr coatings on SS304 plates (20 × 20 × 2 mm 3 in size). Prior to deposition, the substrate was ground and polished, ultrasonic cleaned with acetone and anhydrous ethanol, and then purged with dry nitrogen. A Cr disc with a purity of 99.99% and 50 mm in diameter was used as the target. The chamber was pumped to 9 × 10 − 4 Pa before deposition. During the deposition processes, the Ar pressure, substrate temperature, sputtering power, target-substrate distance, and bias voltage were controlled at 0.2 Pa, 400°C, 200 W, 70 mm, and − 100 V, respectively. By controlling the deposition time to 1 h, 2 h, 3 h, and 4 h, Cr coatings of different columnar grain structures were obtained, labeled Cr-1h, Cr-2h, Cr-3h, and Cr-4h, respectively. 2.2 Characterization The phase structure of the coatings was analyzed using X-ray diffraction (XRD, SmartLab SE, Japan) with Cu-Kα radiation (λ = 0.154 nm) operating at 40 kV and 50 mA. The scan rate was set at 5°·min − 1 with a scan step of 0.01° over a 2θ range of 20–90°. Residual stress within the coatings was measured by XRD utilizing the 2θ-sin 2 ψ method[ 20 ]. For this analysis, the (211) peak of the Cr coatings, which has a standard peak at 81.69° (JCPDS No. 85-1336), an elastic modulus of 250 GPa, and a Poisson’s ratio of 0.21, were selected to determine the variation of the residual stress[ 21 ]. The microstructure and chemical composition were investigated using a field emission scanning electron microscope (FE-SEM, Quanta FEG 250, USA). The top coating was sectioned using a focused ion beam (FIB, Thermo Scientific Helios 5 UX, USA), and the structure of the coating was further characterized using a high-resolution transmission electron microscope (HRTEM, FEI Talos F200X, USA). In addition, the surface morphology and roughness of the Cr coatings were additionally characterized by an atomic force microscope (AFM, Dimension Icon, USA). 2.3 Adhesion tests The adhesion strength of the coating samples was evaluated using both qualitative and quantitative methods. First, the Rockwell hardness C indentation test(HRD-150, Bangyi Precision meter company, China) was performed under a 150 kg load to evaluate the load-bearing capacity of the substrates and the adhesion strength of the coatings to various substrates according to the VDI standard 3198[ 22 ]. Additionally, the cohesion of the coatings to substrates was measured utilizing a scratch tester (MT-5000, Retc, USA) equipped with a Rockwell diamond indenter (200 µm radius, 120° contact angle). A continuously increasing normal force was applied up to a maximum of 100 N for Cr coatings on SS304 plates. The probe was driven at a consistent load rate of 50 N·min − 1 across a scratch length of 5 mm, allowing for quantification of cohesion strength. 3 Results and discussion 3.1 Crystalline structure, composition and microstructure of Cr coatings Figure 1 shows the cross-sectional SEM images of the Cr coatings with various deposition time. With increasing deposition time, the coating thickness increased nearly linearly, from approximately 3.1 µm at 1 h to approximately 10.9 µm at 4 h. While the layer part near the substrate consists of a very fine crystalline film structure, larger columnar grains with almost parallel column boundaries are developed further from this transition zone to the top of the layer. The reason for these structural features is the competitive growth phenomenon[ 23 , 24 ]. The columnar crystals can be explained using the concept of the structure zone model (SZM), proposed by Thornton in 1974[ 25 ]. In their study, it defined the homologation temperature (T h ) as the ratio of the film growth temperature to the melting temperature of the deposited material (both expressed in Kelvin), and the coating structure was divided into five regions based on T h . When 0.3 < T h < 0.5, the coating grows with higher atomic surface mobility, which is favourable for grain boundary migration and surface recrystallisation, and ultimately a homogeneous and dense columnar crystalline structure is formed by extension throughout the coating thickness. The top-view SEM images in Fig. 2 clearly illustrate the surface characteristics of the as-deposited Cr coatings. The surface morphology of the Cr coatings evolves from a relatively smooth appearance to a more faceted structure with increasing coating thickness. This transition can be attributed to atomic shadowing, ion bombardment etching and oblique flux of coating atoms that occur during prolonged magnetron sputtering. A consistent measurement method was adopted to quantify this, where the longest edge of each irregular grain was measured to determine the surface grain size of the coating. To ensure the accuracy and reliability of the collected data, five images were randomly selected for each sample, followed by statistical analysis and the calculation of average values to generate Fig. 2 (e). With increasing deposition time, the columnar grain size gradually increased from approximately 220 nm at 1 h to approximately 800 nm at 4 h. This phenomenon may be attributed to multiple interconnected mechanisms typical of magnetron sputtering deposition. Firstly, competitive texture formation plays a dominant role. At the early stage, Cr(110) grains with lower surface energy grow laterally and dominate the surface. As deposition continues, shadowing effects and vertical growth preference of Cr(211) grains, which have higher surface energy, suppress the lateral expansion of Cr(110), enabling Cr(211) to grow upward and gradually consume adjacent smaller grains. Secondly, in the presence of a negative substrate bias, the inherent ion bombardment during the sputtering process leads to an increase in substrate temperature, which enhances the mobility of adatoms. This elevated mobility promotes surface atom rearrangement and facilitates the coalescence of thermally unstable small grains into larger ones, thereby reducing grain boundary area and the overall system energy[ 26 ]. In conclusion, the columnar grain size of the Cr coating increased significantly with the extension of deposition time during the magnetron sputtering process. The surface morphology of the Cr coatings is quantified by AFM in contact mode at three randomly selected locations over a 20 × 20 µm 2 area, as shown in Fig. 3 . As the deposition time increased from 1 to 4 h, the corresponding average surface roughness measured were 4.38 ± 0.06 nm, 11.5 ± 0.23 nm, 18.4 ± 0.74 nm and 26.0 ± 0.57 nm, respectively. This result could be explained in three ways. First, the grain size distribution of the Cr coating at different deposition time, as shown in Fig. 2 e, indicated that at a deposition time of 1 h, the average grain size of the coating was approximately 220 nm, with grain sizes fluctuating between 100 and 500 nm. As the deposition time increased, the average grain size continued to grow, and the fluctuation range of grain sizes also expanded. This clearly demonstrated that the uniformity of the surface grain size deteriorated, which in turn led to an increase in surface roughness as observed in the measurements. Second, the extension of deposition time induced dynamic changes in grain growth. Specifically, larger grains gradually absorbed smaller neighboring grains, resulting in the formation of even larger grains. During this process, the interface between two grains left behind noticeable grooves, and the depth of these grooves was positively correlated with the grain size, meaning that larger grains led to deeper grooves. This inevitably contributed to the further increase in surface roughness of the coating. Finally, the shadowing effect during the magnetron sputtering process should not have been overlooked, as it significantly affected the surface roughness[ 27 – 29 ]. During magnetron sputtering, atoms ejected from the target moved toward the substrate surface in nearly straight trajectories under the combined action of electric and magnetic fields. If the substrate surface had irregular features such as steps, holes, or grooves, these structures obstructed the path of sputtered atoms, resulting in fewer sputtered atoms reaching the shadowed areas compared to the unshaded regions. Consequently, the coating in the shadowed areas became thinner, while the unshaded regions accumulated a thicker coating, creating height differences between the coating grains. As deposition time increased, this height difference continued to grow, ultimately leading to a rougher surface. The XRD patterns of Cr coatings with various deposition time are shown in Fig. 4 a. At 2θ values of 44.37°, 64.55°, and 81.69°, the diffraction peaks corresponding to Cr (110), (200), and (211) were observed, respectively, confirming that the predominant phase of the coating was body-centered cubic (BCC) Cr (JCPDS No. 85-1336). The varying relative strengths of the (110) and Cr (211) peaks across the samples suggested that the coating's orientation was influenced by the deposition time. The preferred orientation of the Cr coatings was calculated in terms of texture coefficient (T c )[ 30 ]: $$\:{T}_{\left(hkl\right)}=\frac{{I}_{m}\left(hkl\right)/{I}_{0}\left(hkl\right)}{\frac{1}{n}{\sum\:}_{1}^{n}\left[{I}_{m}\left(hkl\right)/{I}_{0}\left(hkl\right)\right]}$$ 1 where I m (hkl) indicated the relative intensity measured for the (hkl) plane, I 0 (hkl) referred to the relative intensity from the JCPDS No. 85-1336, and n represented the total number of peaks under consideration. The calculated T c of Cr coatings with different deposition time are shown in Fig. 4 b. The calculations showed that with increasing deposition time, the Tc value for the (110) orientation initially increased and then decreased, while the Tc value for the (211) orientation followed the opposite trend. However, the fluctuations in both cases were relatively small, indicating that the deposition time had little effect on the crystallographic orientation of the Cr coating. It was noteworthy that the Tc values for the Cr coating on the (211) plane were generally higher than those on the (110) plane, suggesting that the Cr coating tended to grow preferentially in the (211) orientation. This could be explained in terms of both energy and kinetic factors influencing the texture development of the coating[ 31 ]. A peculiar phenomenon occurs during the transition from (110) to (211) in the late stage of the preferential orientation of columnar growth of Cr-4h coatings. During the late competitive growth stage of the coating process, the (211)-oriented grains have more backbonds than the (110)-oriented grains. Consequently, the (110) atoms exhibit high mobility and a fast transverse growth rate, while the (211) atoms exhibit low mobility and a fast longitudinal growth rate. This results in the high diffusivity (110) grains being covered by low diffusivity (211) grains, which intensifies the shadowing effect. At the same time, the high mobility (110) atoms will be trapped on the surface of the low mobility (211) grains and promote their growth[ 24 ]. Figure 5 presents the representative cross-sectional TEM images of the Cr-3h coating. As shown in Fig. 5 a, the Cr coating exhibited a dense columnar crystal structure with a uniform distribution of the Cr element. High-resolution transmission electron microscopy (HR-TEM) was employed to analyze three distinct areas labeled A, B, and C in Fig. 5 a. The results, illustrated in Figs. 5 b- 5 d, reveal the presence of different crystal orientations, and periodic interplanar spacings. Additionally, the selected area electron diffraction (SAED) pattern depicted in Fig. 5 b demonstrated prominent diffraction spots for Cr (110) and Cr (211) planes, which corroborate the findings from XRD. Moreover, the measured crystal lattice fringe spacings for the three areas were found to be 2.044, 2.036, and 2.032 Å, respectively, consistent with the theoretically calculated value for the (110) planes of cubic Cr. The lattice fringe spacings of 1.187, 1.191, and 1.178 Å were indexed as (211) planes, while the spacings of 1.446, 1.493, and 1.488 Å pertain to the (200) planes. The angles between the (110) and (211) planes, as well as the (110) and (200) planes, were measured to be 29.98° and 44.64°, respectively, closely matching the theoretical values for Cr. The reasons for the shift in preferential orientation from (110) to (211) during the later stages of columnar crystal growth are as follows: According to the analysis of the orientation evolution process, during the initial island growth stage, grains with lower surface energy grew faster in the lateral direction and occupied a larger area. In the subsequent layer-by-layer growth stage, due to the shielding effect of grains with higher surface energy, grains with lower surface energy were at a disadvantage in the later stages of growth, causing their growth rate to slow down. In contrast, grains with higher surface energy dominated in vertical growth and gradually expanded outward, continuously compressing the growth space for the lower surface energy grains. As the layer-by-layer growth progressed into the middle and late stages, the number of high-surface-energy grains increased, eventually leading to preferential growth towards the high-surface-energy planes. The surface energy of the Cr(110) orientation was the lowest, while the strain energy of the Cr(211) orientation was the lowest. In summary, thicker Cr coatings ultimately exhibited a (211) crystal plane orientation with a relatively faster growth rate. Therefore, TEM analysis confirmed that the orientation results of the Cr coating prepared by magnetron sputtering were consistent with the XRD measurements, and the coating exhibited a dense columnar grain structure. 3.2 Residual stress Residual stress in coatings has attracted significant attention due to its widespread presence and its impact on coating adhesion performance[ 32 , 33 ]. Therefore, the variation of residual stress of Cr coating with various columnar grain structures were further studied, the residual stress was determined by the 2θ-sin 2 ψ method in the following Eq. ( 2 ): $$\:\sigma\:=-\frac{E}{2\left(1+\nu\:\right)}\frac{\pi\:}{180}\text{cot}{(\theta\:}_{0})\frac{{\partial\:\left(2\theta\:\right)}_{\psi\:}}{{\partial\:Sin}^{2}\psi\:}=KM$$ 2 where K was the stress constant, which could be calculated from Eq. ( 3 ), E and ν were elastic modulus and Poisson’s ratio of the coating, θ 0 was the Bragg’s angle obtained from the (hkl) planes of the stress-free sample, θ was the Bragg’s angle, and ψ was the angle between the sample surface and the diffraction plane. M was equal to the slope of the 2θ - sin 2 ψ plot, expressed as Eq. ( 4 ). $$\:K=-\frac{E}{2\left(1+\nu\:\right)}\frac{\pi\:}{180}\text{cot}{(\theta\:}_{0})$$ 3 $$\:M=\frac{{\partial\:\left(2\theta\:\right)}_{\psi\:}}{{\partial\:Sin}^{2}\psi\:}$$ 4 The evolution of residual stress in the Cr coatings with various columnar grain structures is shown in Fig. 6 . All Cr coatings, regardless of columnar grain structures, exhibited compressive stresses, which aligned with findings from previous studies of MS Cr coatings[ 34 ]. The generation of interstitials due to ion bombardment collision cascades, along with the incorporation of excess atoms into the grains via grain boundary diffusion, contributed to the compressive stress observed in the MS coating[ 35 ]. With the progressive increase in coating thickness and grain size, the residual compressive stress within the Cr coating exhibits a gradual reduction. This stress relaxation is primarily attributed to the microstructural evolution occurring during the deposition process. Specifically, as deposition time increases, the heating time of the substrate surface coating increases accordingly and the sputtered particles continue to bombard the coating surface under negative bias pressure. These two factors lead to the surface particles acquiring more energy, which promotes the aggregation and growth of the columnar intergranular grains of the substrate surface coating. This reduces the number and total area of grain boundaries and weakens their ability to capture the atoms adhering to the surface. Additionally, compressive stress at the grain boundaries inhibits atomic diffusion by raising the chemical potential of atoms at the grain boundaries[ 24 ]. Beyond these microstructural effects, plastic deformation occurring in the substrate near the film-substrate interface during coating thickening also contributes to the reduction of residual stress[ 36 ]. These combined factors lead to the progressive relaxation of compressive stress within the coating. Previous studies have shown that appropriate residual compressive stress can enhance coating adhesion performance[ 37 – 39 ]. The coating adhesion performance will be discussed in detail in the following sections. 3.3 Adhesion performance The Rockwell indentation results for the Cr coatings with various columnar grain structures are shown in Fig. 7 . According to the evaluation of the indentation test conducted in accordance with VDI 3198 guidelines and research by Vidakis[ 22 ], the adhesion strength of the coating on SS304 plates was found to be satisfactory. The adhesion strength of Cr coatings with different deposition time was qualitatively assessed by comparing the SEM images of the indentations (Fig. 7 (a–d)) with the mechanism diagram outlined in the VDI 3198 guidelines. The adhesion grade of Cr-1h was determined to be HF2, while the adhesion grade of Cr-2h, Cr-3h, and Cr-4h improved to HF1. Further observation of the magnified SEM images (e-h) showed significant coating delamination and separation between the coating and substrate in the Cr-1h sample. In contrast, the Cr-2h, Cr-3h, and Cr-4h coatings exhibited no delamination and only minor peeling. Examination of the spalled regions revealed that spallation was due to reticular cracks formed by the intersection of radial and circular cracks, which resulted in approximately rectangular spalled areas[ 40 ]. Additionally, the data revealed that the indentation cracks for Cr-2h, Cr-3h, and Cr-4h were less than those observed in Cr-1h, indicating that thicker coatings offer improved load-bearing capacity and enhanced resistance to plastic deformation. The scratch test is the most established and widely used method for quantitatively evaluating the adhesion strength of coatings to substrates in both industrial and research settings. Following the scratch test, three critical normal loads can were identified: Lc 1 (first appearance of cracks), Lc 2 (first detachment chip), and Lc 3 (complete peeling). These were typically observed using SEM or optical microscopy (OM). Specifically, Lc 1 indicated the cohesion within the coating, while Lc 2 reflected the adhesion between the coating and the substrate[ 41 , 42 ]. A standard scratch test apparatus is employed to quantitatively assess the cohesion properties of the Cr coating with different columnar grain structures, as shown in Fig. 8 . When the average tensile stress within the coating surpassed a critical threshold, cracks began to form, which helped to dissipate the elastic energy stored in the coating. Typically, the cohesion strength of the coating was characterized by the critical load (L 1 ) observed during a scratch test, which represented the lower critical load linked to the initial cracking event. As the coating columnar grain size increased from 220 nm to 800 nm, the critical load of the coating initially rose and then declined. The cohesion strengths for Cr-1h, Cr-2h, Cr-3h, and Cr-4h were approximately 2.2 N, 12.6 N, 21.8 N, and 17.8 N, respectively, with Cr-3h coating exhibiting the highest critical load, reflecting superior resistance to mechanical load and stress-induced plastic deformation. This showed that the coating columnar grain structures had a significant effect on the critical normal load of the coating. To validate the reliability of the friction force curve, the scratch's morphology is further examined using SEM, as depicted in Fig. 9 . Microscopic observation proves to be the most reliable method for identifying cracks in the coating, as it effectively distinguishes between cohesive failure within the coating and adhesive failure at the coating-substrate interface[ 43 ]. The SEM results indicated that 5 mm residual scratch grooves were formed due to the plastic deformation of the coating in contact with the substrate under progressively increasing loads. The enlarged rectangles highlighted the onset of crack failure, marking the first cohesion failure[ 44 ]. Post-scratch testing revealed that various thicknesses of Cr coatings exhibited a pronounced occurrence of densely arranged tensile cracks. The first crack in the Cr-1h coating developed earlier, whereas the initial crack in the Cr-3h sample manifested later. These tensile cracks can were attributed to the tensile radial stresses present at the edge of the indenter contact during the scratch test[ 45 , 46 ]. Tensile cracking occurred as a response to minimize the stress induced by the bending of the hard Cr coatings on the relatively soft steel substrate, which experienced plastic deformation during the scratch test. Overall, it was evident that the friction force curve results from the scratch test aligned well with the observed scratch patterns. To further elucidate the relationship between coating structure and cohesion, this study defined the columnar grain structure of the coating as a three-dimensional concept, encompassing the grain size of the coating surface and the coating thickness. Based on the experimental data in Figs. 1 and 2 , the grain size and thickness of the coating increased with deposition time, while the cohesion of the coating exhibited a trend of first increasing and then decreasing, reaching its peak at Cr-3h. AFM and residual stress measurements revealed that the columnar grain structure of the coating significantly influenced its surface roughness and residual stress. Surface roughness increased with grain size and coating thickness, which was attributed to grain growth and the shadowing effect. Residual stress decreased as grain size and coating thickness increased, likely due to a reduction in grain boundaries, allowing stress at grain boundaries to relax more effectively. This relaxation mechanism became increasingly prominent with larger grain sizes. In Cr-1h, Cr-2h, and Cr-3h coatings, cohesion gradually improved, which could be attributed to the reduction in compressive residual stress. Excessive compressive residual stress may induce shear stress, adversely affecting cohesion. Previous studies have demonstrated that appropriate residual stress enhances internal bonding within the coating and improves cohesion[ 47 , 48 ]. However, compared to Cr-3h, the cohesion of the Cr-4h coating decreased despite its lower residual compressive stress. This was due to the detrimental effect of excessive surface roughness on coating cohesion. Excessive roughness may have introduced voids, gaps, or discontinuities within the coating, weakening adhesion and compromising mechanical integrity[ 49 ]. As noted by Liu et al. high surface roughness under external loads could have led to stress concentration at surface peaks and valleys, which were more likely to initiate cracks, increasing the risk of cohesive failure[ 50 ]. Under external loading, the stress concentration at the peaks and valleys of the Cr-4h surface contributed to its reduced cohesion. Furthermore, the mechanism by which surface roughness and residual stress influence the cohesion of the coating is elaborated in detail using a schematic diagram, as shown in Fig. 10 . When the deposition time was short, the coating exhibited small surface grain size and thickness, along with reduced surface roughness and high residual stress. Excessive residual stress caused coating warpage, leading to shear stresses within the coating and at the interfaces. This resulted in the formation of microcracks, significantly reducing the cohesion of the coating. Conversely, when the deposition time was extended, the coating displayed large surface grain size and thickness, increased surface roughness, and reduced residual stress. However, excessive surface roughness introduced peaks and valleys, which, under external loads, caused stress concentration. This can lead to crack formation in the coating, ultimately diminishing its cohesion. In summary, the synergistic effects of residual stress and surface roughness significantly impacted coating cohesion. Optimizing the columnar grain structure within an appropriate range during deposition was crucial for achieving strong and reliable cohesion. This study determined that the coating achieved maximum cohesion of 21.8 N when the surface grain size was 690 nm, the coating thickness was 8.5 µm, the surface roughness was 18.4 nm, and the residual compressive stress was 1.12 GPa. 4 Conclusions In this study, Cr coatings with different columnar grain structures were prepared on SS304 substrates by adjusting the deposition time, effectively addressing the critical issue of insufficient coating cohesion. The results revealed that the deposition time significantly affected the columnar structure, surface roughness, residual stress, and cohesion strength of the Cr coatings. As the deposition time increased, the columnar grain size of the Cr coating grew, leading to an increase in surface roughness and a decrease in residual stress. The increase in surface roughness was primarily attributed to the enlargement of grain size and the shadowing effect, while the reduction in residual stress was due to grain growth and the decrease in grain boundaries, which allowed stress to be released at the boundaries. Notably, the best cohesion was achieved with a coating deposited for 3 h, with a thickness of approximately 8.5 µm and a grain size of 690 ± 208 nm. This was due to the synergistic optimization of residual stress and surface roughness. When the coating was subjected to external loads, excessive residual stress could induce crack formation, while higher surface roughness could cause stress concentration at the peaks. Both factors promoted crack formation and subsequently reduced the cohesion of the Cr coating. The optimal values for surface roughness and residual compressive stress were found to be 18.4 ± 0.73 nm and approximately 1.12 GPa, respectively. This study emphasizes the importance of adjusting the columnar grain structures of Cr coatings to improve cohesiveness, which has important basic research implications and engineering application value. Declarations Author Contribution Sitian Zhu: Conceptualization, Methodology, Visualisation, Writing - original draft.Wenxin Liu: Investigation, Data collection, Writing - original draft.Zhigang Xu: Conceptualization, Supervision, Project administration, Writing - review & editing.Xuehao Geng: Investigation, Data collection.Chuanbin Wang: Supervision, Funding acquisition, Resources, Writing - review & editing. References Li C, Bell T (2006) Corrosion properties of plasma nitrided AISI 410 martensitic stainless steel in 3.5% NaCl and 1% HCl aqueous solutions. Corros. Sci 48: 2036–2049. https://doi.org/10.1016/j.corsci.2005.08.011 Liu X, Guo Y, Wang Y et al (2024) Difference between thermal-induced martensite and deformation-induced martensite in 304 austenitic stainless steel. J. Mater. Sci 59: 21974–21986. https://doi.org/10.1007/s10853-024-10476-z Mo J, Li J, Wu P et al (2024) The effects of Ni/Cr on diffusion behavior of Cu in 304 stainless steel. Vacuum 222: 112955. https://doi.org/10.1016/j.vacuum.2024.112955 Yin L, Wang C, Li P et al (2025) Self-healing behavior in high-deposition-rate sputtered Al·Al 2 O 3 nanocomposite coatings for enhanced corrosion resistance. Vacuum 235: 114134. https://doi.org/10.1016/j.vacuum.2025.114134 Mello CB, Mansur RAF, Santos NM et al (2017) Experimental study of mechanical and tribological behavior of nitrogen ion-implanted chromium thin films. Surf. Coat. Technol 312: 123–127. https://doi.org/10.1016/j.surfcoat.2016.12.100 Hu M, Shen M, Liu Z et al (2018) Self-ion bombarded Cr films: Crystallographic orientation and oxidation behaviour. Corros. Sci 143: 212–220. https://doi.org/10.1016/j.corsci.2018.08.016 Wang B, Tian X, Gong C et al (2025) Internal cylindrical cathode arc deposited Cr coatings on the interior of slender tube: The influence of arc currents. Vacuum 232: 113883. https://doi.org/10.1016/j.vacuum.2024.113883 Wu B, Gao S, Xue W et al (2024) Designing TiB 2 /Cr multilayer coatings on Ti6Al4V substrate for optimized wear resistance. Surf. Sci. Technol 2: 29. https://doi.org/10.1007/s44251-025-00075-8 Liu Z, Mou C, Yin P et al (2023) Deposition of DLC film on the inner surface of N80 pipeline by hollow cathode PECVD. Surf. Sci. Technol 1: 12. https://doi.org/10.1007/s44251-023-00012-7 Wei X, Ma Y, Ma M et al (2025) Trivalent chromium sealing of the PEO coating on AZ91D magnesium alloy. Surf. Sci. Technol 3: 20. https://doi.org/10.1007/s44251-025-00081-w Liu W, Jiao D, Ding H et al (2023) Corrosion resistance of CrN film deposited by high-power impulse magnetron sputtering on SS304 in a simulated environment for proton exchange membrane fuel cells. Int. J. Hydrogen Energy 48: 25901–25917. https://doi.org/10.1016/j.ijhydene.2023.03.265 Wang D, Tian T, Lin S et al (2023) Tensile mechanism of wear-resistant Cr/CrN/Cr/CrAlN multilayer film. Vacuum 207: 111405. https://doi.org/10.1016/j.vacuum.2022.111405 Zhang Y, Chen Q, Wang Z et al (2007) Preparation of Cr hard coatings by ion beam assisted electron beam vapor deposition on Ni and Cu substrates. Surf. Coat. Technol 201: 5190–5193. https://doi.org/10.1016/j.surfcoat.2006.07.138 Lin J, Moore JJ, Sproul WD et al (2009) Modulated pulse power sputtered chromium coatings. Thin Solid Films 518: 1566–1570. https://doi.org/10.1016/j.tsf.2009.09.118 Liu W, Wang C, Liu L et al (2025) Influence of substrate surface roughness on the adhesion of magnetron sputtered Cr coating. International Journal of Modern Physics B 39: 2540038. https://doi.org/10.1142/S0217979225400387 Bai X, Cai Q, Xie W et al (2023) Effect of ion control strategies on the deposition rate and properties of copper films in bipolar pulse high power impulse magnetron sputtering. J. Mater. Sci 58: 1243–1259. https://doi.org/10.1007/s10853-022-08036-4 Ding X, Cui M, Jiao J et al (2025) Surface feature of the substrate via key factor on adhesion of Cr/Cr 2 N multilayer and alloy substrate. Vacuum 233: 113991. https://doi.org/10.1016/j.vacuum.2024.113991 Geng Z, Peng J, Xu Z et al (2024) Fabrication of amorphous AlMo 0.5 NbTa 0.5 TiZr RHEA coatings and the impact of deposition temperature on microstructure and properties. Surf. Coat. Technol 487:131036. https://doi.org/10.1016/j.surfcoat.2024.131036 Li H, Liu B, Liu D et al (2024) Enhanced adhesion and corrosion resistance through the modulation of a metallic Ti underlayer thickness. Mater. Today Commun. 41: 110474. https://doi.org/10.1016/j.mtcomm.2024.110474 Quillin K, Yeom H, Pu X et al (2023) Effects of elevated temperature exposure on the residual stress state and microstructure of PVD Cr coatings on SiC investigated via in situ X-ray diffraction and transmission electron microscopy. Materials Science and Engineering: A 879: 145273. https://doi.org/10.1016/j.msea.2023.145273 Quillin K, Yeom H, Dabney T et al (2022) Microstructural and nanomechanical studies of PVD Cr coatings on SiC for LWR fuel cladding applications. Surf. Coat. Technol 441: 128577. https://doi.org/10.1016/j.surfcoat.2022.128577 Vidakis N, Antoniadis A, Bilalis N (2003) The VDI 3198 indentation test evaluation of a reliable qualitative control for layered compounds. J. Mater. Process. Technol 143–144: 481–485. https://doi.org/10.1016/S0924-0136(03)00300-5 Hofer AM, Schlacher J, Keckes J et al (2014) Sputtered molybdenum films: Structure and property evolution with film thickness. Vacuum 99: 149–152. https://doi.org/10.1016/j.vacuum.2013.05.018 Daniel R, Martinschitz K, Keckes J et al (2010) The origin of stresses in magnetron-sputtered thin films with zone T structures. Acta Mater 58: 2621–2633. https://doi.org/10.1016/j.actamat.2009.12.048 Thornton JA (1974) Influence of apparatus geometry and deposition conditions on the structure and topography of thick sputtered coatings. Journal of Vacuum Science and Technology 11: 666–670. https://doi.org/10.1116/1.1312732 Le M, Sohn YU, Lim JW et al (2010) Effect of sputtering power on the nucleation and growth of Cu films deposited by magnetron sputtering. Mater. Trans 51: 116–120. https://doi.org/10.2320/matertrans.M2009183 Ferreira F, Serra R, Cavaleiro A et al (2016) Additional control of bombardment by deep oscillation magnetron sputtering: Effect on the microstructure and topography of Cr thin films. Thin Solid Films 619: 250–260. https://doi.org/10.1016/j.tsf.2016.10.054 Liang H, Xu J, Zhou D et al (2016) Thickness dependent microstructural and electrical properties of TiN thin films prepared by DC reactive magnetron sputtering. Ceram. Int 42: 2642–2647. https://doi.org/10.1016/j.ceramint.2015.10.070 Karabacak T (2011) Thin-film growth dynamics with shadowing and re-emission effects. J. Nanophotonics 5: 052501–0525018. https://doi.org/10.1117/1.3543822 Jones MI, McColl IR, Grant DM (2000) Effect of substrate preparation and deposition conditions on the preferred orientation of TiN coatings deposited by RF reactive sputtering. Surf. Coat. Technol 132: 143–151. https://doi.org/10.1016/S0257-8972(00)00867- Abadias G (2008) Stress and preferred orientation in nitride-based PVD coatings. Surf. Coat. Technol 202: 2223–2235. https://doi.org/10.1016/j.surfcoat.2007.08.029 Qiu L, Zhu X, Xu K et al (2017) Internal stress on adhesion of hard coatings synthesized by multi-arc ion plating. Surf. Coat. Technol 332: 267–274. https://doi.org/10.1016/j.surfcoat.2017.07.076 Ali R, Sebastiani M, Bemporad E (2015) Influence of Ti-TiN multilayer PVD-coatings design on residual stresses and adhesion. Mater. Des 75: 47–56. https://doi.org/10.1016/j.matdes.2015.03.007 Sidelev DV, Bestetti M, Bleykher GA et al (2018) Deposition of Cr films by hot target magnetron sputtering on biased substrates. Surf. Coat. Technol 350: 560–568. https://doi.org/10.1016/j.surfcoat.2018.07.047 Magnfält D, Abadias G, Sarakinos K et al (2013) Atom insertion into grain boundaries and stress generation in physically vapor deposited films. Appl. Phys. Lett 103. https://doi.org/10.1063/1.4817669 Seidl W, Bartosik M, Kolozsvári S et al (2018) Influence of coating thickness and substrate on stresses and mechanical properties of (Ti, Al, Ta) N/(Al, Cr) N multilayers. Surf. Coat. Technol 347: 92–98. https://doi.org/10.1016/j.surfcoat.2018.04.060 Tönshoff HK, Seegers H (2000) Influence of residual stress gradients on the adhesion strength of sputtered hard coatings. Thin Solid Films 377–378: 340–345. https://doi.org/10.1016/S0040-6090(00)01308-0 Zhao S, Yang Y, Li J et al (2008) Effect of deposition processes on residual stress profiles along the thickness in (Ti,Al)N films. Surf. Coat. Technol 202: 5185–5189. https://doi.org/10.1016/j.surfcoat.2008.06.048 Bobzin K, Kalscheuer C, Tayyab M (2023) Effect of CrAIN coating properties on impact fatigue of tool steel. Surf. Coat. Technol 471: 129869. https://doi.org/10.1016/j.surfcoat.2023.129869 Fu H, He Y, Yang J et al (2022) Enhancing adhesion strength of PVD AlCrN coating by novel volcano-shaped micro-textures: Experimental study and mechanism insight. Surf. Coat. Technol 445: 128712. https://doi.org/10.1016/j.surfcoat.2022.128712 Chen W, Zheng J, Lin Y et al (2015) Comparison of AlCrN and AlCrTiSiN coatings deposited on the surface of plasma nitrocarburized high carbon steels. Appl. Surf. Sci 332: 525–532. https://doi.org/10.1016/j.apsusc.2015.01.212 Zhang X, Tian X, Zhao Z et al (2019) Evaluation of the adhesion and failure mechanism of the hard CrN coatings on different substrates. Surf. Coat. Technol 364: 135–143. https://doi.org/10.1016/j.surfcoat.2019.01.059 Sveen S, Andersson JM, M’Saoubi R et al (2013) Scratch adhesion characteristics of PVD TiAlN deposited on high speed steel, cemented carbide and PCBN substrates. Wear 308: 133–141. https://doi.org/10.1016/j.wear.2013.08.025 Akhter R, Zhou Z, Xie Z et al (2021) TiN versus TiSiN coatings in indentation, scratch and wear setting. Appl. Surf. Sci 563: 150356. https://doi.org/10.1016/j.apsusc.2021.150356 Meneses-Amador A, Jiménez-Tinoco LF, Reséndiz-Calderon CD et al (2015) Numerical evaluation of scratch tests on boride layers. Surf. Coat. Technol 284: 182–191. https://doi.org/10.1016/j.surfcoat.2015.06.088 Vega-Morón RC, Rodríguez Castro GA, Melo-Máximo DV et al (2018) Adhesion and mechanical properties of Ti films deposited by DC magnetron sputtering. Surf. Coat. Technol 349: 1137–1147. https://doi.org/10.1016/j.surfcoat.2018.05.078 Bushroa AR, Rahbari R, Masjuki HH et al (2012) Approximation of crystallite size and microstrain via XRD line broadening analysis in TiSiN thin films. Vacuum 86 : 1107–1112. https://doi.org/10.1016/j.vacuum.2011.10.011 Liu Y, Huang J, Claypool JB et al (2015) Structure and corrosion behavior of sputter deposited cerium oxide based coatings with various thickness on Al 2024-T3 alloy substrates. Appl. Surf. Sci 355: 805–813. https://doi.org/10.1016/j.apsusc.2015.07.173 Sharma P, Ponte F, Lima M et al (2023) Plasma etching of polycarbonate surfaces for improved adhesion of Cr coatings. Appl. Surf. Sci 637: 157903. https://doi.org/10.1016/j.apsusc.2023.157903 Liu H, Gong Y, Ma D et al (2024) The adhesion strength and stability of TiN films deposited on magnesium substrate with different substrate roughness. Ceram. Int 50: 21658–21666. https://doi.org/10.1016/j.ceramint.2024.03.278 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 28 Aug, 2025 Reviews received at journal 27 Aug, 2025 Reviews received at journal 26 Aug, 2025 Reviewers agreed at journal 07 Aug, 2025 Reviewers agreed at journal 06 Aug, 2025 Reviewers invited by journal 05 Aug, 2025 Editor assigned by journal 04 Aug, 2025 Submission checks completed at journal 04 Aug, 2025 First submitted to journal 31 Jul, 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-7263123","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":497290667,"identity":"1e08c197-90ec-4d41-9d8c-f61e73b910aa","order_by":0,"name":"Sitian Zhu","email":"","orcid":"","institution":"Wuhan University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Sitian","middleName":"","lastName":"Zhu","suffix":""},{"id":497290668,"identity":"9f9986e1-c3e1-4f4f-b3f5-42624d128b32","order_by":1,"name":"Wenxin Liu","email":"","orcid":"","institution":"Wuhan University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Wenxin","middleName":"","lastName":"Liu","suffix":""},{"id":497290669,"identity":"5c9dd4c0-ef26-4349-a358-e59080264a06","order_by":2,"name":"Zhigang Xu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7klEQVRIiWNgGAWjYDACCcYGCIO9gQ3COEC0Fp4DQC0JRGmBMxKI1CI/u7n5xc8dtYkbbr4xe8z7g0GO70YC4+cCPFoY5xxss+w9c9zY4HaOuTFPAoOx5I0EZukZeLQwSyS2GfC2HZMzuJ27TRqoJXHDjQQ2Zh48WtiAWgz/th3jMbh5FqylnqAWHonE5se8bTVyBjd4wVoSDAhpkQDawizbdsBY8kz+N8k5aRKGM888bJbGp0V+Rvrjj2/b6hL7jh9Lk3hjYyPPdzz54Gd8WsDeYWA4DLcViGGRixswf2BgqCOkaBSMglEwCkYyAACLrkxf1/FBxAAAAABJRU5ErkJggg==","orcid":"","institution":"Wuhan University of Technology","correspondingAuthor":true,"prefix":"","firstName":"Zhigang","middleName":"","lastName":"Xu","suffix":""},{"id":497290670,"identity":"26f9a829-94bc-47b3-96eb-4afc704f185a","order_by":3,"name":"Xuehao Geng","email":"","orcid":"","institution":"Inner Mongolia North Heavy Industries Group Limited Company Nanjing Institute","correspondingAuthor":false,"prefix":"","firstName":"Xuehao","middleName":"","lastName":"Geng","suffix":""},{"id":497290671,"identity":"6a17d9c8-a11e-4f6c-83d2-b3326bf75c4a","order_by":4,"name":"Chuanbin Wang","email":"","orcid":"","institution":"Wuhan University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Chuanbin","middleName":"","lastName":"Wang","suffix":""}],"badges":[],"createdAt":"2025-07-31 14:08:35","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7263123/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7263123/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":88626454,"identity":"6b3a4d5c-41f7-4a33-b4d0-3731a804c825","added_by":"auto","created_at":"2025-08-08 12:57:40","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":82977,"visible":true,"origin":"","legend":"\u003cp\u003e(a-d) Cross-sectional SEM images of Cr coatings deposited from 1 to 4 h.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7263123/v1/549c979cd2664d07fbc93022.jpg"},{"id":88625021,"identity":"a87a51bc-61b7-4329-948c-2b9ef1046766","added_by":"auto","created_at":"2025-08-08 12:41:40","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":109013,"visible":true,"origin":"","legend":"\u003cp\u003e(a-d) SEM surface morphologies of Cr coatings deposited from 1 to 4 h, and (e) statistical column size distribution.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7263123/v1/f4b4334633c8b8badbd50f1a.jpg"},{"id":88625023,"identity":"d59b35f6-abdd-48f6-ba4b-eaff7510eea7","added_by":"auto","created_at":"2025-08-08 12:41:40","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":81432,"visible":true,"origin":"","legend":"\u003cp\u003eTypically top-viewed and 3-dimensional AFM morphology images of the as-deposited Cr coatings of (a) Cr-1h, (b) Cr-2h, (c) Cr-3h, and (d) Cr-4h.\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7263123/v1/c09c03dd1a85c3d91d816cf5.jpg"},{"id":88625022,"identity":"3dae002f-cdc7-4b2a-b2e1-3023f23d7413","added_by":"auto","created_at":"2025-08-08 12:41:40","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":67488,"visible":true,"origin":"","legend":"\u003cp\u003e(a) XRD patterns and (b) texture coefficient of Cr coatings with various deposition time.\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7263123/v1/2a3e1ccca05fe114990c59bd.jpg"},{"id":88625039,"identity":"f9368043-618e-4554-96e7-c17ab8f74159","added_by":"auto","created_at":"2025-08-08 12:41:41","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":227213,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Overview of bright-field TEM micrograph and EDS spectrum of the Cr-3h coating, (b-d) enlarged view of the SAED and HRTEM images of the region A, B, and C in (a), respectively.\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7263123/v1/654e6e568c55eed2d7f9e82a.jpg"},{"id":88625028,"identity":"13fe2989-62c3-4ac7-89a2-cfcbeb21a593","added_by":"auto","created_at":"2025-08-08 12:41:40","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":91623,"visible":true,"origin":"","legend":"\u003cp\u003e(a-d) the diffraction peaks of different ψ angles on the (211) crystal plane, (e-h) the 2θ ~ sin\u003csup\u003e2\u003c/sup\u003e ψ linear fitting results, and (i) evolution of residual stresses of the Cr coatings with different columnar grain structures.\u003c/p\u003e","description":"","filename":"Untitled.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7263123/v1/ecd2365d6d95c1455fc837cc.jpg"},{"id":88626886,"identity":"619780c7-28c6-40a3-b06d-0d0dd7974ac9","added_by":"auto","created_at":"2025-08-08 13:05:40","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":131304,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of the indentation of the as-deposited Cr coatings with different columnar grain structures of (a) Cr-1h, (b) Cr-2h, (c) Cr-3h, and (d) Cr-4h, (e-h) enlarged view images of the boxed regions in (a-d).\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7263123/v1/35f0c2ba7f6cac71ad9190ea.jpg"},{"id":88625029,"identity":"e38988a5-5266-4a9e-9389-80d502d17792","added_by":"auto","created_at":"2025-08-08 12:41:40","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":133757,"visible":true,"origin":"","legend":"\u003cp\u003e(a-d) Fraction force curves and three-dimensional (3D) surface morphologies of Cr coatings with different columnar grain structures.\u003c/p\u003e","description":"","filename":"8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7263123/v1/71e6b07d3ddf269e06788b4b.jpg"},{"id":88625041,"identity":"0a531c23-6cc3-4803-b8e4-6abb29fee835","added_by":"auto","created_at":"2025-08-08 12:41:41","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":99646,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of the scratch of the as-deposited Cr coatings with different columnar grain structures of (a) Cr-1h, (b) Cr-2h, (c) Cr-3h, and (d) Cr-4h, (e-h) enlarged view images of the boxed regions in (a-d).\u003c/p\u003e","description":"","filename":"9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7263123/v1/62019dcb2ec9edc2b32b8486.jpg"},{"id":88625048,"identity":"a796ae03-c577-4c45-993d-8b67136c610e","added_by":"auto","created_at":"2025-08-08 12:41:41","extension":"jpg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":75199,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic of surface roughness and residual stress effects on coating cohesion: (a) short deposition time, (b) long deposition time.\u003c/p\u003e","description":"","filename":"10.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7263123/v1/e91de7ce4e8d315a15175e6c.jpg"},{"id":88627710,"identity":"bd64b8e5-a9bc-46e4-aeff-00b7bfe27fce","added_by":"auto","created_at":"2025-08-08 13:13:42","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1647518,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7263123/v1/7920675d-34e2-418c-bf31-1de5a7a62e36.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The enhanced cohesive performance of magnetron sputtered Cr coatings on steel substrate via controlling columnar grain structures","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eStainless steel (SS304) is widely used in extreme environment applications such as mechanical engineering, marine, medical and aerospace[\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. To prolong the life and durability of stainless steel components, high performance protective coatings are often applied to the surface[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Among these coatings, chromium (Cr) coatings have been extensively researched and utilized to enhance the mechanical performance of engineered components due to their exceptional physical and chemical properties, including low friction coefficient, excellent corrosion resistance, high oxidation resistance, and improved thermal stability[\u003cspan additionalcitationids=\"CR6 CR7 CR8\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Moreover, Cr is abundant, has a high ionization rate, boasts excellent production efficiency, and is notably cost - effective[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Currently, magnetron sputtering (MS) is one of the most common methods for preparing Cr coatings, as it has attracted much attention from researchers due to its environmental friendliness, non-pollution, and the smooth surface of the prepared coatings[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Although the research on MS Cr coatings has a long history and their composition, structure, and properties have been extensively explored, significant challenges remain.\u003c/p\u003e\u003cp\u003eNumerous studies have shown that MS Cr coatings often suffer from issues such as low adhesion or cracking, which prevent the full realization of their excellent properties and ultimately affect the long-term protection of the substrate[\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In fact, the adhesion between a coating and a substrate can be divided into two components: the coating's own cohesive force and the interfacial bonding force between the coating and the substrate. However, most studies on improvement strategies have focused on interfacial bonding force[\u003cspan additionalcitationids=\"CR17 CR18\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], often ignoring the effect of the columnar grain structure of magnetron-sputtered coatings on coating cohesion, especially with regard to the size of coating surface particles and coating thickness. Clarifying the intrinsic relationship between columnar grain structure and coating cohesion is of significant theoretical and practical importance for optimizing coating design at the microstructural level and substantially enhancing coating cohesion.\u003c/p\u003e\u003cp\u003eIn this study, Cr coatings with varying columnar grain structures were deposited on SS304 substrates by adjusting the deposition time during the magnetron sputtering process. A systematic investigation was conducted to assess the impact of deposition time on the columnar grain structures, surface roughness, residual stress, and cohesive strength of Cr coatings. The relationship between coating columnar grain structures, residual stress, and coating cohesion was established, providing valuable data to support the enhancement of cohesion in thick Cr coatings.\u003c/p\u003e"},{"header":"2 Experimental procedures","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Coating preparation\u003c/h2\u003e\u003cp\u003eDC magnetron sputtering (PD-400C, Pudi Vacuum Equipment Company, China) was utilized to deposit Cr coatings on SS304 plates (20 \u0026times; 20 \u0026times; 2 mm\u003csup\u003e3\u003c/sup\u003e in size). Prior to deposition, the substrate was ground and polished, ultrasonic cleaned with acetone and anhydrous ethanol, and then purged with dry nitrogen. A Cr disc with a purity of 99.99% and 50 mm in diameter was used as the target. The chamber was pumped to 9 \u0026times; 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e Pa before deposition. During the deposition processes, the Ar pressure, substrate temperature, sputtering power, target-substrate distance, and bias voltage were controlled at 0.2 Pa, 400\u0026deg;C, 200 W, 70 mm, and \u0026minus;\u0026thinsp;100 V, respectively. By controlling the deposition time to 1 h, 2 h, 3 h, and 4 h, Cr coatings of different columnar grain structures were obtained, labeled Cr-1h, Cr-2h, Cr-3h, and Cr-4h, respectively.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Characterization\u003c/h2\u003e\u003cp\u003eThe phase structure of the coatings was analyzed using X-ray diffraction (XRD, SmartLab SE, Japan) with Cu-Kα radiation (λ\u0026thinsp;=\u0026thinsp;0.154 nm) operating at 40 kV and 50 mA. The scan rate was set at 5\u0026deg;\u0026middot;min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with a scan step of 0.01\u0026deg; over a 2θ range of 20\u0026ndash;90\u0026deg;. Residual stress within the coatings was measured by XRD utilizing the 2θ-sin\u003csup\u003e2\u003c/sup\u003e ψ method[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. For this analysis, the (211) peak of the Cr coatings, which has a standard peak at 81.69\u0026deg; (JCPDS No. 85-1336), an elastic modulus of 250 GPa, and a Poisson\u0026rsquo;s ratio of 0.21, were selected to determine the variation of the residual stress[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The microstructure and chemical composition were investigated using a field emission scanning electron microscope (FE-SEM, Quanta FEG 250, USA). The top coating was sectioned using a focused ion beam (FIB, Thermo Scientific Helios 5 UX, USA), and the structure of the coating was further characterized using a high-resolution transmission electron microscope (HRTEM, FEI Talos F200X, USA). In addition, the surface morphology and roughness of the Cr coatings were additionally characterized by an atomic force microscope (AFM, Dimension Icon, USA).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Adhesion tests\u003c/h2\u003e\u003cp\u003eThe adhesion strength of the coating samples was evaluated using both qualitative and quantitative methods. First, the Rockwell hardness C indentation test(HRD-150, Bangyi Precision meter company, China) was performed under a 150 kg load to evaluate the load-bearing capacity of the substrates and the adhesion strength of the coatings to various substrates according to the VDI standard 3198[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Additionally, the cohesion of the coatings to substrates was measured utilizing a scratch tester (MT-5000, Retc, USA) equipped with a Rockwell diamond indenter (200 \u0026micro;m radius, 120\u0026deg; contact angle). A continuously increasing normal force was applied up to a maximum of 100 N for Cr coatings on SS304 plates. The probe was driven at a consistent load rate of 50 N\u0026middot;min\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e across a scratch length of 5 mm, allowing for quantification of cohesion strength.\u003c/p\u003e\u003c/div\u003e"},{"header":"3 Results and discussion","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Crystalline structure, composition and microstructure of Cr coatings\u003c/h2\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the cross-sectional SEM images of the Cr coatings with various deposition time. With increasing deposition time, the coating thickness increased nearly linearly, from approximately 3.1 \u0026micro;m at 1 h to approximately 10.9 \u0026micro;m at 4 h. While the layer part near the substrate consists of a very fine crystalline film structure, larger columnar grains with almost parallel column boundaries are developed further from this transition zone to the top of the layer. The reason for these structural features is the competitive growth phenomenon[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The columnar crystals can be explained using the concept of the structure zone model (SZM), proposed by Thornton in 1974[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. In their study, it defined the homologation temperature (T\u003csub\u003eh\u003c/sub\u003e) as the ratio of the film growth temperature to the melting temperature of the deposited material (both expressed in Kelvin), and the coating structure was divided into five regions based on T\u003csub\u003eh\u003c/sub\u003e. When 0.3\u0026thinsp;\u0026lt;\u0026thinsp;T\u003csub\u003eh\u003c/sub\u003e\u0026lt; 0.5, the coating grows with higher atomic surface mobility, which is favourable for grain boundary migration and surface recrystallisation, and ultimately a homogeneous and dense columnar crystalline structure is formed by extension throughout the coating thickness.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe top-view SEM images in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e clearly illustrate the surface characteristics of the as-deposited Cr coatings. The surface morphology of the Cr coatings evolves from a relatively smooth appearance to a more faceted structure with increasing coating thickness. This transition can be attributed to atomic shadowing, ion bombardment etching and oblique flux of coating atoms that occur during prolonged magnetron sputtering. A consistent measurement method was adopted to quantify this, where the longest edge of each irregular grain was measured to determine the surface grain size of the coating. To ensure the accuracy and reliability of the collected data, five images were randomly selected for each sample, followed by statistical analysis and the calculation of average values to generate Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(e). With increasing deposition time, the columnar grain size gradually increased from approximately 220 nm at 1 h to approximately 800 nm at 4 h. This phenomenon may be attributed to multiple interconnected mechanisms typical of magnetron sputtering deposition. Firstly, competitive texture formation plays a dominant role. At the early stage, Cr(110) grains with lower surface energy grow laterally and dominate the surface. As deposition continues, shadowing effects and vertical growth preference of Cr(211) grains, which have higher surface energy, suppress the lateral expansion of Cr(110), enabling Cr(211) to grow upward and gradually consume adjacent smaller grains. Secondly, in the presence of a negative substrate bias, the inherent ion bombardment during the sputtering process leads to an increase in substrate temperature, which enhances the mobility of adatoms. This elevated mobility promotes surface atom rearrangement and facilitates the coalescence of thermally unstable small grains into larger ones, thereby reducing grain boundary area and the overall system energy[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. In conclusion, the columnar grain size of the Cr coating increased significantly with the extension of deposition time during the magnetron sputtering process.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe surface morphology of the Cr coatings is quantified by AFM in contact mode at three randomly selected locations over a 20 \u0026times; 20 \u0026micro;m\u003csup\u003e2\u003c/sup\u003e area, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. As the deposition time increased from 1 to 4 h, the corresponding average surface roughness measured were 4.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06 nm, 11.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.23 nm, 18.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.74 nm and 26.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57 nm, respectively. This result could be explained in three ways. First, the grain size distribution of the Cr coating at different deposition time, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ee, indicated that at a deposition time of 1 h, the average grain size of the coating was approximately 220 nm, with grain sizes fluctuating between 100 and 500 nm. As the deposition time increased, the average grain size continued to grow, and the fluctuation range of grain sizes also expanded. This clearly demonstrated that the uniformity of the surface grain size deteriorated, which in turn led to an increase in surface roughness as observed in the measurements. Second, the extension of deposition time induced dynamic changes in grain growth. Specifically, larger grains gradually absorbed smaller neighboring grains, resulting in the formation of even larger grains. During this process, the interface between two grains left behind noticeable grooves, and the depth of these grooves was positively correlated with the grain size, meaning that larger grains led to deeper grooves. This inevitably contributed to the further increase in surface roughness of the coating. Finally, the shadowing effect during the magnetron sputtering process should not have been overlooked, as it significantly affected the surface roughness[\u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. During magnetron sputtering, atoms ejected from the target moved toward the substrate surface in nearly straight trajectories under the combined action of electric and magnetic fields. If the substrate surface had irregular features such as steps, holes, or grooves, these structures obstructed the path of sputtered atoms, resulting in fewer sputtered atoms reaching the shadowed areas compared to the unshaded regions. Consequently, the coating in the shadowed areas became thinner, while the unshaded regions accumulated a thicker coating, creating height differences between the coating grains. As deposition time increased, this height difference continued to grow, ultimately leading to a rougher surface.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe XRD patterns of Cr coatings with various deposition time are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea. At 2θ values of 44.37\u0026deg;, 64.55\u0026deg;, and 81.69\u0026deg;, the diffraction peaks corresponding to Cr (110), (200), and (211) were observed, respectively, confirming that the predominant phase of the coating was body-centered cubic (BCC) Cr (JCPDS No. 85-1336). The varying relative strengths of the (110) and Cr (211) peaks across the samples suggested that the coating's orientation was influenced by the deposition time.\u003c/p\u003e\u003cp\u003eThe preferred orientation of the Cr coatings was calculated in terms of texture coefficient (T\u003csub\u003ec\u003c/sub\u003e)[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]:\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:{T}_{\\left(hkl\\right)}=\\frac{{I}_{m}\\left(hkl\\right)/{I}_{0}\\left(hkl\\right)}{\\frac{1}{n}{\\sum\\:}_{1}^{n}\\left[{I}_{m}\\left(hkl\\right)/{I}_{0}\\left(hkl\\right)\\right]}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ewhere I\u003csub\u003em\u003c/sub\u003e(hkl) indicated the relative intensity measured for the (hkl) plane, I\u003csub\u003e0\u003c/sub\u003e(hkl) referred to the relative intensity from the JCPDS No. 85-1336, and n represented the total number of peaks under consideration.\u003c/p\u003e\u003cp\u003eThe calculated T\u003csub\u003ec\u003c/sub\u003e of Cr coatings with different deposition time are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb. The calculations showed that with increasing deposition time, the Tc value for the (110) orientation initially increased and then decreased, while the Tc value for the (211) orientation followed the opposite trend. However, the fluctuations in both cases were relatively small, indicating that the deposition time had little effect on the crystallographic orientation of the Cr coating. It was noteworthy that the Tc values for the Cr coating on the (211) plane were generally higher than those on the (110) plane, suggesting that the Cr coating tended to grow preferentially in the (211) orientation. This could be explained in terms of both energy and kinetic factors influencing the texture development of the coating[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. A peculiar phenomenon occurs during the transition from (110) to (211) in the late stage of the preferential orientation of columnar growth of Cr-4h coatings. During the late competitive growth stage of the coating process, the (211)-oriented grains have more backbonds than the (110)-oriented grains. Consequently, the (110) atoms exhibit high mobility and a fast transverse growth rate, while the (211) atoms exhibit low mobility and a fast longitudinal growth rate. This results in the high diffusivity (110) grains being covered by low diffusivity (211) grains, which intensifies the shadowing effect. At the same time, the high mobility (110) atoms will be trapped on the surface of the low mobility (211) grains and promote their growth[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e presents the representative cross-sectional TEM images of the Cr-3h coating. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea, the Cr coating exhibited a dense columnar crystal structure with a uniform distribution of the Cr element. High-resolution transmission electron microscopy (HR-TEM) was employed to analyze three distinct areas labeled A, B, and C in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea. The results, illustrated in Figs.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb-\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ed, reveal the presence of different crystal orientations, and periodic interplanar spacings. Additionally, the selected area electron diffraction (SAED) pattern depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb demonstrated prominent diffraction spots for Cr (110) and Cr (211) planes, which corroborate the findings from XRD. Moreover, the measured crystal lattice fringe spacings for the three areas were found to be 2.044, 2.036, and 2.032 \u0026Aring;, respectively, consistent with the theoretically calculated value for the (110) planes of cubic Cr. The lattice fringe spacings of 1.187, 1.191, and 1.178 \u0026Aring; were indexed as (211) planes, while the spacings of 1.446, 1.493, and 1.488 \u0026Aring; pertain to the (200) planes. The angles between the (110) and (211) planes, as well as the (110) and (200) planes, were measured to be 29.98\u0026deg; and 44.64\u0026deg;, respectively, closely matching the theoretical values for Cr. The reasons for the shift in preferential orientation from (110) to (211) during the later stages of columnar crystal growth are as follows: According to the analysis of the orientation evolution process, during the initial island growth stage, grains with lower surface energy grew faster in the lateral direction and occupied a larger area. In the subsequent layer-by-layer growth stage, due to the shielding effect of grains with higher surface energy, grains with lower surface energy were at a disadvantage in the later stages of growth, causing their growth rate to slow down. In contrast, grains with higher surface energy dominated in vertical growth and gradually expanded outward, continuously compressing the growth space for the lower surface energy grains. As the layer-by-layer growth progressed into the middle and late stages, the number of high-surface-energy grains increased, eventually leading to preferential growth towards the high-surface-energy planes. The surface energy of the Cr(110) orientation was the lowest, while the strain energy of the Cr(211) orientation was the lowest. In summary, thicker Cr coatings ultimately exhibited a (211) crystal plane orientation with a relatively faster growth rate. Therefore, TEM analysis confirmed that the orientation results of the Cr coating prepared by magnetron sputtering were consistent with the XRD measurements, and the coating exhibited a dense columnar grain structure.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Residual stress\u003c/h2\u003e\u003cp\u003eResidual stress in coatings has attracted significant attention due to its widespread presence and its impact on coating adhesion performance[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. Therefore, the variation of residual stress of Cr coating with various columnar grain structures were further studied, the residual stress was determined by the 2θ-sin\u003csup\u003e2\u003c/sup\u003eψ method in the following Eq.\u0026nbsp;(\u003cspan refid=\"Equ2\" class=\"InternalRef\"\u003e2\u003c/span\u003e):\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:\\sigma\\:=-\\frac{E}{2\\left(1+\\nu\\:\\right)}\\frac{\\pi\\:}{180}\\text{cot}{(\\theta\\:}_{0})\\frac{{\\partial\\:\\left(2\\theta\\:\\right)}_{\\psi\\:}}{{\\partial\\:Sin}^{2}\\psi\\:}=KM$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ewhere K was the stress constant, which could be calculated from Eq.\u0026nbsp;(\u003cspan refid=\"Equ3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), E and ν were elastic modulus and Poisson\u0026rsquo;s ratio of the coating, θ\u003csub\u003e0\u003c/sub\u003e was the Bragg\u0026rsquo;s angle obtained from the (hkl) planes of the stress-free sample, θ was the Bragg\u0026rsquo;s angle, and ψ was the angle between the sample surface and the diffraction plane. M was equal to the slope of the 2θ - sin\u003csup\u003e2\u003c/sup\u003eψ plot, expressed as Eq.\u0026nbsp;(\u003cspan refid=\"Equ4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003cdiv id=\"Equ3\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ3\" name=\"EquationSource\"\u003e\n$$\\:K=-\\frac{E}{2\\left(1+\\nu\\:\\right)}\\frac{\\pi\\:}{180}\\text{cot}{(\\theta\\:}_{0})$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e3\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equ4\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ4\" name=\"EquationSource\"\u003e\n$$\\:M=\\frac{{\\partial\\:\\left(2\\theta\\:\\right)}_{\\psi\\:}}{{\\partial\\:Sin}^{2}\\psi\\:}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e4\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe evolution of residual stress in the Cr coatings with various columnar grain structures is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. All Cr coatings, regardless of columnar grain structures, exhibited compressive stresses, which aligned with findings from previous studies of MS Cr coatings[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. The generation of interstitials due to ion bombardment collision cascades, along with the incorporation of excess atoms into the grains via grain boundary diffusion, contributed to the compressive stress observed in the MS coating[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. With the progressive increase in coating thickness and grain size, the residual compressive stress within the Cr coating exhibits a gradual reduction. This stress relaxation is primarily attributed to the microstructural evolution occurring during the deposition process. Specifically, as deposition time increases, the heating time of the substrate surface coating increases accordingly and the sputtered particles continue to bombard the coating surface under negative bias pressure. These two factors lead to the surface particles acquiring more energy, which promotes the aggregation and growth of the columnar intergranular grains of the substrate surface coating. This reduces the number and total area of grain boundaries and weakens their ability to capture the atoms adhering to the surface. Additionally, compressive stress at the grain boundaries inhibits atomic diffusion by raising the chemical potential of atoms at the grain boundaries[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Beyond these microstructural effects, plastic deformation occurring in the substrate near the film-substrate interface during coating thickening also contributes to the reduction of residual stress[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. These combined factors lead to the progressive relaxation of compressive stress within the coating. Previous studies have shown that appropriate residual compressive stress can enhance coating adhesion performance[\u003cspan additionalcitationids=\"CR38\" citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. The coating adhesion performance will be discussed in detail in the following sections.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Adhesion performance\u003c/h2\u003e\u003cp\u003eThe Rockwell indentation results for the Cr coatings with various columnar grain structures are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e. According to the evaluation of the indentation test conducted in accordance with VDI 3198 guidelines and research by Vidakis[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], the adhesion strength of the coating on SS304 plates was found to be satisfactory. The adhesion strength of Cr coatings with different deposition time was qualitatively assessed by comparing the SEM images of the indentations (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(a\u0026ndash;d)) with the mechanism diagram outlined in the VDI 3198 guidelines. The adhesion grade of Cr-1h was determined to be HF2, while the adhesion grade of Cr-2h, Cr-3h, and Cr-4h improved to HF1. Further observation of the magnified SEM images (e-h) showed significant coating delamination and separation between the coating and substrate in the Cr-1h sample. In contrast, the Cr-2h, Cr-3h, and Cr-4h coatings exhibited no delamination and only minor peeling. Examination of the spalled regions revealed that spallation was due to reticular cracks formed by the intersection of radial and circular cracks, which resulted in approximately rectangular spalled areas[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Additionally, the data revealed that the indentation cracks for Cr-2h, Cr-3h, and Cr-4h were less than those observed in Cr-1h, indicating that thicker coatings offer improved load-bearing capacity and enhanced resistance to plastic deformation.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe scratch test is the most established and widely used method for quantitatively evaluating the adhesion strength of coatings to substrates in both industrial and research settings. Following the scratch test, three critical normal loads can were identified: Lc\u003csub\u003e1\u003c/sub\u003e (first appearance of cracks), Lc\u003csub\u003e2\u003c/sub\u003e (first detachment chip), and Lc\u003csub\u003e3\u003c/sub\u003e (complete peeling). These were typically observed using SEM or optical microscopy (OM). Specifically, Lc\u003csub\u003e1\u003c/sub\u003e indicated the cohesion within the coating, while Lc\u003csub\u003e2\u003c/sub\u003e reflected the adhesion between the coating and the substrate[\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]. A standard scratch test apparatus is employed to quantitatively assess the cohesion properties of the Cr coating with different columnar grain structures, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e. When the average tensile stress within the coating surpassed a critical threshold, cracks began to form, which helped to dissipate the elastic energy stored in the coating. Typically, the cohesion strength of the coating was characterized by the critical load (L\u003csub\u003e1\u003c/sub\u003e) observed during a scratch test, which represented the lower critical load linked to the initial cracking event. As the coating columnar grain size increased from 220 nm to 800 nm, the critical load of the coating initially rose and then declined. The cohesion strengths for Cr-1h, Cr-2h, Cr-3h, and Cr-4h were approximately 2.2 N, 12.6 N, 21.8 N, and 17.8 N, respectively, with Cr-3h coating exhibiting the highest critical load, reflecting superior resistance to mechanical load and stress-induced plastic deformation. This showed that the coating columnar grain structures had a significant effect on the critical normal load of the coating.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eTo validate the reliability of the friction force curve, the scratch's morphology is further examined using SEM, as depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e. Microscopic observation proves to be the most reliable method for identifying cracks in the coating, as it effectively distinguishes between cohesive failure within the coating and adhesive failure at the coating-substrate interface[\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]. The SEM results indicated that 5 mm residual scratch grooves were formed due to the plastic deformation of the coating in contact with the substrate under progressively increasing loads. The enlarged rectangles highlighted the onset of crack failure, marking the first cohesion failure[\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]. Post-scratch testing revealed that various thicknesses of Cr coatings exhibited a pronounced occurrence of densely arranged tensile cracks. The first crack in the Cr-1h coating developed earlier, whereas the initial crack in the Cr-3h sample manifested later. These tensile cracks can were attributed to the tensile radial stresses present at the edge of the indenter contact during the scratch test[\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e]. Tensile cracking occurred as a response to minimize the stress induced by the bending of the hard Cr coatings on the relatively soft steel substrate, which experienced plastic deformation during the scratch test. Overall, it was evident that the friction force curve results from the scratch test aligned well with the observed scratch patterns.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eTo further elucidate the relationship between coating structure and cohesion, this study defined the columnar grain structure of the coating as a three-dimensional concept, encompassing the grain size of the coating surface and the coating thickness. Based on the experimental data in Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the grain size and thickness of the coating increased with deposition time, while the cohesion of the coating exhibited a trend of first increasing and then decreasing, reaching its peak at Cr-3h. AFM and residual stress measurements revealed that the columnar grain structure of the coating significantly influenced its surface roughness and residual stress. Surface roughness increased with grain size and coating thickness, which was attributed to grain growth and the shadowing effect. Residual stress decreased as grain size and coating thickness increased, likely due to a reduction in grain boundaries, allowing stress at grain boundaries to relax more effectively. This relaxation mechanism became increasingly prominent with larger grain sizes.\u003c/p\u003e\u003cp\u003eIn Cr-1h, Cr-2h, and Cr-3h coatings, cohesion gradually improved, which could be attributed to the reduction in compressive residual stress. Excessive compressive residual stress may induce shear stress, adversely affecting cohesion. Previous studies have demonstrated that appropriate residual stress enhances internal bonding within the coating and improves cohesion[\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e, \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]. However, compared to Cr-3h, the cohesion of the Cr-4h coating decreased despite its lower residual compressive stress. This was due to the detrimental effect of excessive surface roughness on coating cohesion. Excessive roughness may have introduced voids, gaps, or discontinuities within the coating, weakening adhesion and compromising mechanical integrity[\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e]. As noted by Liu et al. high surface roughness under external loads could have led to stress concentration at surface peaks and valleys, which were more likely to initiate cracks, increasing the risk of cohesive failure[\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e]. Under external loading, the stress concentration at the peaks and valleys of the Cr-4h surface contributed to its reduced cohesion.\u003c/p\u003e\u003cp\u003eFurthermore, the mechanism by which surface roughness and residual stress influence the cohesion of the coating is elaborated in detail using a schematic diagram, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e. When the deposition time was short, the coating exhibited small surface grain size and thickness, along with reduced surface roughness and high residual stress. Excessive residual stress caused coating warpage, leading to shear stresses within the coating and at the interfaces. This resulted in the formation of microcracks, significantly reducing the cohesion of the coating. Conversely, when the deposition time was extended, the coating displayed large surface grain size and thickness, increased surface roughness, and reduced residual stress. However, excessive surface roughness introduced peaks and valleys, which, under external loads, caused stress concentration. This can lead to crack formation in the coating, ultimately diminishing its cohesion.\u003c/p\u003e\u003cp\u003eIn summary, the synergistic effects of residual stress and surface roughness significantly impacted coating cohesion. Optimizing the columnar grain structure within an appropriate range during deposition was crucial for achieving strong and reliable cohesion. This study determined that the coating achieved maximum cohesion of 21.8 N when the surface grain size was 690 nm, the coating thickness was 8.5 \u0026micro;m, the surface roughness was 18.4 nm, and the residual compressive stress was 1.12 GPa.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"4 Conclusions","content":"\u003cp\u003eIn this study, Cr coatings with different columnar grain structures were prepared on SS304 substrates by adjusting the deposition time, effectively addressing the critical issue of insufficient coating cohesion. The results revealed that the deposition time significantly affected the columnar structure, surface roughness, residual stress, and cohesion strength of the Cr coatings. As the deposition time increased, the columnar grain size of the Cr coating grew, leading to an increase in surface roughness and a decrease in residual stress. The increase in surface roughness was primarily attributed to the enlargement of grain size and the shadowing effect, while the reduction in residual stress was due to grain growth and the decrease in grain boundaries, which allowed stress to be released at the boundaries. Notably, the best cohesion was achieved with a coating deposited for 3 h, with a thickness of approximately 8.5 \u0026micro;m and a grain size of 690\u0026thinsp;\u0026plusmn;\u0026thinsp;208 nm. This was due to the synergistic optimization of residual stress and surface roughness. When the coating was subjected to external loads, excessive residual stress could induce crack formation, while higher surface roughness could cause stress concentration at the peaks. Both factors promoted crack formation and subsequently reduced the cohesion of the Cr coating. The optimal values for surface roughness and residual compressive stress were found to be 18.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.73 nm and approximately 1.12 GPa, respectively. This study emphasizes the importance of adjusting the columnar grain structures of Cr coatings to improve cohesiveness, which has important basic research implications and engineering application value.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eSitian Zhu: Conceptualization, Methodology, Visualisation, Writing - original draft.Wenxin Liu: Investigation, Data collection, Writing - original draft.Zhigang Xu: Conceptualization, Supervision, Project administration, Writing - review \u0026amp; editing.Xuehao Geng: Investigation, Data collection.Chuanbin Wang: Supervision, Funding acquisition, Resources, Writing - review \u0026amp; editing.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLi C, Bell T (2006) Corrosion properties of plasma nitrided AISI 410 martensitic stainless steel in 3.5% NaCl and 1% HCl aqueous solutions. Corros. Sci 48: 2036\u0026ndash;2049. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.corsci.2005.08.011\u003c/span\u003e\u003cspan address=\"10.1016/j.corsci.2005.08.011\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiu X, Guo Y, Wang Y et al (2024) Difference between thermal-induced martensite and deformation-induced martensite in 304 austenitic stainless steel. J. Mater. Sci 59: 21974\u0026ndash;21986. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10853-024-10476-z\u003c/span\u003e\u003cspan address=\"10.1007/s10853-024-10476-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMo J, Li J, Wu P et al (2024) The effects of Ni/Cr on diffusion behavior of Cu in 304 stainless steel. Vacuum 222: 112955. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vacuum.2024.112955\u003c/span\u003e\u003cspan address=\"10.1016/j.vacuum.2024.112955\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYin L, Wang C, Li P et al (2025) Self-healing behavior in high-deposition-rate sputtered Al\u0026middot;Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e nanocomposite coatings for enhanced corrosion resistance. Vacuum 235: 114134. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vacuum.2025.114134\u003c/span\u003e\u003cspan address=\"10.1016/j.vacuum.2025.114134\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMello CB, Mansur RAF, Santos NM et al (2017) Experimental study of mechanical and tribological behavior of nitrogen ion-implanted chromium thin films. Surf. Coat. Technol 312: 123\u0026ndash;127. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2016.12.100\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2016.12.100\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHu M, Shen M, Liu Z et al (2018) Self-ion bombarded Cr films: Crystallographic orientation and oxidation behaviour. Corros. Sci 143: 212\u0026ndash;220. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.corsci.2018.08.016\u003c/span\u003e\u003cspan address=\"10.1016/j.corsci.2018.08.016\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWang B, Tian X, Gong C et al (2025) Internal cylindrical cathode arc deposited Cr coatings on the interior of slender tube: The influence of arc currents. Vacuum 232: 113883. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vacuum.2024.113883\u003c/span\u003e\u003cspan address=\"10.1016/j.vacuum.2024.113883\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWu B, Gao S, Xue W et al (2024) Designing TiB\u003csub\u003e2\u003c/sub\u003e/Cr multilayer coatings on Ti6Al4V substrate for optimized wear resistance. Surf. Sci. Technol 2: 29. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s44251-025-00075-8\u003c/span\u003e\u003cspan address=\"10.1007/s44251-025-00075-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiu Z, Mou C, Yin P et al (2023) Deposition of DLC film on the inner surface of N80 pipeline by hollow cathode PECVD. Surf. Sci. Technol 1: 12. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s44251-023-00012-7\u003c/span\u003e\u003cspan address=\"10.1007/s44251-023-00012-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWei X, Ma Y, Ma M et al (2025) Trivalent chromium sealing of the PEO coating on AZ91D magnesium alloy. Surf. Sci. Technol 3: 20. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s44251-025-00081-w\u003c/span\u003e\u003cspan address=\"10.1007/s44251-025-00081-w\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiu W, Jiao D, Ding H et al (2023) Corrosion resistance of CrN film deposited by high-power impulse magnetron sputtering on SS304 in a simulated environment for proton exchange membrane fuel cells. Int. J. Hydrogen Energy 48: 25901\u0026ndash;25917. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.ijhydene.2023.03.265\u003c/span\u003e\u003cspan address=\"10.1016/j.ijhydene.2023.03.265\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWang D, Tian T, Lin S et al (2023) Tensile mechanism of wear-resistant Cr/CrN/Cr/CrAlN multilayer film. Vacuum 207: 111405. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vacuum.2022.111405\u003c/span\u003e\u003cspan address=\"10.1016/j.vacuum.2022.111405\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang Y, Chen Q, Wang Z et al (2007) Preparation of Cr hard coatings by ion beam assisted electron beam vapor deposition on Ni and Cu substrates. Surf. Coat. Technol 201: 5190\u0026ndash;5193. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2006.07.138\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2006.07.138\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLin J, Moore JJ, Sproul WD et al (2009) Modulated pulse power sputtered chromium coatings. Thin Solid Films 518: 1566\u0026ndash;1570. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.tsf.2009.09.118\u003c/span\u003e\u003cspan address=\"10.1016/j.tsf.2009.09.118\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiu W, Wang C, Liu L et al (2025) Influence of substrate surface roughness on the adhesion of magnetron sputtered Cr coating. International Journal of Modern Physics B 39: 2540038. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1142/S0217979225400387\u003c/span\u003e\u003cspan address=\"10.1142/S0217979225400387\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBai X, Cai Q, Xie W et al (2023) Effect of ion control strategies on the deposition rate and properties of copper films in bipolar pulse high power impulse magnetron sputtering. J. Mater. Sci 58: 1243\u0026ndash;1259. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10853-022-08036-4\u003c/span\u003e\u003cspan address=\"10.1007/s10853-022-08036-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDing X, Cui M, Jiao J et al (2025) Surface feature of the substrate via key factor on adhesion of Cr/Cr\u003csub\u003e2\u003c/sub\u003eN multilayer and alloy substrate. Vacuum 233: 113991. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vacuum.2024.113991\u003c/span\u003e\u003cspan address=\"10.1016/j.vacuum.2024.113991\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGeng Z, Peng J, Xu Z et al (2024) Fabrication of amorphous AlMo\u003csub\u003e0.5\u003c/sub\u003eNbTa\u003csub\u003e0.5\u003c/sub\u003eTiZr RHEA coatings and the impact of deposition temperature on microstructure and properties. Surf. Coat. Technol 487:131036. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2024.131036\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2024.131036\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLi H, Liu B, Liu D et al (2024) Enhanced adhesion and corrosion resistance through the modulation of a metallic Ti underlayer thickness. Mater. Today Commun. 41: 110474. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.mtcomm.2024.110474\u003c/span\u003e\u003cspan address=\"10.1016/j.mtcomm.2024.110474\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQuillin K, Yeom H, Pu X et al (2023) Effects of elevated temperature exposure on the residual stress state and microstructure of PVD Cr coatings on SiC investigated via in situ X-ray diffraction and transmission electron microscopy. Materials Science and Engineering: A 879: 145273. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.msea.2023.145273\u003c/span\u003e\u003cspan address=\"10.1016/j.msea.2023.145273\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQuillin K, Yeom H, Dabney T et al (2022) Microstructural and nanomechanical studies of PVD Cr coatings on SiC for LWR fuel cladding applications. Surf. Coat. Technol 441: 128577. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2022.128577\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2022.128577\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eVidakis N, Antoniadis A, Bilalis N (2003) The VDI 3198 indentation test evaluation of a reliable qualitative control for layered compounds. J. Mater. Process. Technol 143\u0026ndash;144: 481\u0026ndash;485. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0924-0136(03)00300-5\u003c/span\u003e\u003cspan address=\"10.1016/S0924-0136(03)00300-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHofer AM, Schlacher J, Keckes J et al (2014) Sputtered molybdenum films: Structure and property evolution with film thickness. Vacuum 99: 149\u0026ndash;152. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vacuum.2013.05.018\u003c/span\u003e\u003cspan address=\"10.1016/j.vacuum.2013.05.018\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDaniel R, Martinschitz K, Keckes J et al (2010) The origin of stresses in magnetron-sputtered thin films with zone T structures. Acta Mater 58: 2621\u0026ndash;2633. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.actamat.2009.12.048\u003c/span\u003e\u003cspan address=\"10.1016/j.actamat.2009.12.048\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eThornton JA (1974) Influence of apparatus geometry and deposition conditions on the structure and topography of thick sputtered coatings. Journal of Vacuum Science and Technology 11: 666\u0026ndash;670. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1116/1.1312732\u003c/span\u003e\u003cspan address=\"10.1116/1.1312732\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLe M, Sohn YU, Lim JW et al (2010) Effect of sputtering power on the nucleation and growth of Cu films deposited by magnetron sputtering. Mater. Trans 51: 116\u0026ndash;120. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2320/matertrans.M2009183\u003c/span\u003e\u003cspan address=\"10.2320/matertrans.M2009183\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFerreira F, Serra R, Cavaleiro A et al (2016) Additional control of bombardment by deep oscillation magnetron sputtering: Effect on the microstructure and topography of Cr thin films. Thin Solid Films 619: 250\u0026ndash;260. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.tsf.2016.10.054\u003c/span\u003e\u003cspan address=\"10.1016/j.tsf.2016.10.054\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiang H, Xu J, Zhou D et al (2016) Thickness dependent microstructural and electrical properties of TiN thin films prepared by DC reactive magnetron sputtering. Ceram. Int 42: 2642\u0026ndash;2647. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.ceramint.2015.10.070\u003c/span\u003e\u003cspan address=\"10.1016/j.ceramint.2015.10.070\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKarabacak T (2011) Thin-film growth dynamics with shadowing and re-emission effects. J. Nanophotonics 5: 052501\u0026ndash;0525018. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1117/1.3543822\u003c/span\u003e\u003cspan address=\"10.1117/1.3543822\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJones MI, McColl IR, Grant DM (2000) Effect of substrate preparation and deposition conditions on the preferred orientation of TiN coatings deposited by RF reactive sputtering. Surf. Coat. Technol 132: 143\u0026ndash;151. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0257-8972(00)00867-\u003c/span\u003e\u003cspan address=\"10.1016/S0257-8972(00)00867-\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAbadias G (2008) Stress and preferred orientation in nitride-based PVD coatings. Surf. Coat. Technol 202: 2223\u0026ndash;2235. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2007.08.029\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2007.08.029\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQiu L, Zhu X, Xu K et al (2017) Internal stress on adhesion of hard coatings synthesized by multi-arc ion plating. Surf. Coat. Technol 332: 267\u0026ndash;274. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2017.07.076\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2017.07.076\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAli R, Sebastiani M, Bemporad E (2015) Influence of Ti-TiN multilayer PVD-coatings design on residual stresses and adhesion. Mater. Des 75: 47\u0026ndash;56. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.matdes.2015.03.007\u003c/span\u003e\u003cspan address=\"10.1016/j.matdes.2015.03.007\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSidelev DV, Bestetti M, Bleykher GA et al (2018) Deposition of Cr films by hot target magnetron sputtering on biased substrates. Surf. Coat. Technol 350: 560\u0026ndash;568. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2018.07.047\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2018.07.047\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMagnf\u0026auml;lt D, Abadias G, Sarakinos K et al (2013) Atom insertion into grain boundaries and stress generation in physically vapor deposited films. Appl. Phys. Lett 103. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1063/1.4817669\u003c/span\u003e\u003cspan address=\"10.1063/1.4817669\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSeidl W, Bartosik M, Kolozsv\u0026aacute;ri S et al (2018) Influence of coating thickness and substrate on stresses and mechanical properties of (Ti, Al, Ta) N/(Al, Cr) N multilayers. Surf. Coat. Technol 347: 92\u0026ndash;98. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2018.04.060\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2018.04.060\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eT\u0026ouml;nshoff HK, Seegers H (2000) Influence of residual stress gradients on the adhesion strength of sputtered hard coatings. Thin Solid Films 377\u0026ndash;378: 340\u0026ndash;345. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0040-6090(00)01308-0\u003c/span\u003e\u003cspan address=\"10.1016/S0040-6090(00)01308-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhao S, Yang Y, Li J et al (2008) Effect of deposition processes on residual stress profiles along the thickness in (Ti,Al)N films. Surf. Coat. Technol 202: 5185\u0026ndash;5189. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2008.06.048\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2008.06.048\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBobzin K, Kalscheuer C, Tayyab M (2023) Effect of CrAIN coating properties on impact fatigue of tool steel. Surf. Coat. Technol 471: 129869. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2023.129869\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2023.129869\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFu H, He Y, Yang J et al (2022) Enhancing adhesion strength of PVD AlCrN coating by novel volcano-shaped micro-textures: Experimental study and mechanism insight. Surf. Coat. Technol 445: 128712. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2022.128712\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2022.128712\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChen W, Zheng J, Lin Y et al (2015) Comparison of AlCrN and AlCrTiSiN coatings deposited on the surface of plasma nitrocarburized high carbon steels. Appl. Surf. Sci 332: 525\u0026ndash;532. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.apsusc.2015.01.212\u003c/span\u003e\u003cspan address=\"10.1016/j.apsusc.2015.01.212\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang X, Tian X, Zhao Z et al (2019) Evaluation of the adhesion and failure mechanism of the hard CrN coatings on different substrates. Surf. Coat. Technol 364: 135\u0026ndash;143. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2019.01.059\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2019.01.059\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSveen S, Andersson JM, M\u0026rsquo;Saoubi R et al (2013) Scratch adhesion characteristics of PVD TiAlN deposited on high speed steel, cemented carbide and PCBN substrates. Wear 308: 133\u0026ndash;141. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.wear.2013.08.025\u003c/span\u003e\u003cspan address=\"10.1016/j.wear.2013.08.025\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAkhter R, Zhou Z, Xie Z et al (2021) TiN versus TiSiN coatings in indentation, scratch and wear setting. Appl. Surf. Sci 563: 150356. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.apsusc.2021.150356\u003c/span\u003e\u003cspan address=\"10.1016/j.apsusc.2021.150356\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMeneses-Amador A, Jim\u0026eacute;nez-Tinoco LF, Res\u0026eacute;ndiz-Calderon CD et al (2015) Numerical evaluation of scratch tests on boride layers. Surf. Coat. Technol 284: 182\u0026ndash;191. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2015.06.088\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2015.06.088\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eVega-Mor\u0026oacute;n RC, Rodr\u0026iacute;guez Castro GA, Melo-M\u0026aacute;ximo DV et al (2018) Adhesion and mechanical properties of Ti films deposited by DC magnetron sputtering. Surf. Coat. Technol 349: 1137\u0026ndash;1147. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.surfcoat.2018.05.078\u003c/span\u003e\u003cspan address=\"10.1016/j.surfcoat.2018.05.078\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBushroa AR, Rahbari R, Masjuki HH et al (2012) Approximation of crystallite size and microstrain via XRD line broadening analysis in TiSiN thin films. Vacuum 86 : 1107\u0026ndash;1112. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.vacuum.2011.10.011\u003c/span\u003e\u003cspan address=\"10.1016/j.vacuum.2011.10.011\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiu Y, Huang J, Claypool JB et al (2015) Structure and corrosion behavior of sputter deposited cerium oxide based coatings with various thickness on Al 2024-T3 alloy substrates. Appl. Surf. Sci 355: 805\u0026ndash;813. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.apsusc.2015.07.173\u003c/span\u003e\u003cspan address=\"10.1016/j.apsusc.2015.07.173\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSharma P, Ponte F, Lima M et al (2023) Plasma etching of polycarbonate surfaces for improved adhesion of Cr coatings. Appl. Surf. Sci 637: 157903. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.apsusc.2023.157903\u003c/span\u003e\u003cspan address=\"10.1016/j.apsusc.2023.157903\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiu H, Gong Y, Ma D et al (2024) The adhesion strength and stability of TiN films deposited on magnesium substrate with different substrate roughness. Ceram. Int 50: 21658\u0026ndash;21666. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.ceramint.2024.03.278\u003c/span\u003e\u003cspan address=\"10.1016/j.ceramint.2024.03.278\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\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":"surface-science-and-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Surface Science and Technology](https://link.springer.com/journal/44251)","snPcode":"44251","submissionUrl":"https://submission.springernature.com/new-submission/44251/3","title":"Surface Science and Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Columnar grain structures, Residual stress, Cohesion strength, Magnetron sputtering","lastPublishedDoi":"10.21203/rs.3.rs-7263123/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7263123/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study investigates the effect of columnar grain structure on the cohesion of chromium (Cr) coatings, which is crucial for preventing cracking and enhancing durability. Cr coatings with varying columnar grain structures were prepared by adjusting magnetron sputtering deposition time. The relationship between grain structure, surface roughness, residual stress, and cohesion was examined. XRD results showed that all Cr coatings exhibited preferred orientations along the (211) plane. As deposition time increased, both grain size and coating thickness grew, leading to higher surface roughness and reduced residual stress, which in turn affected coating cohesion. The peak cohesion of 21.8 N was achieved when the grain size reached 690 nm and the coating thickness was 8.5 \u0026micro;m. Excessive residual stress and high surface roughness promoted crack formation, reducing cohesion. This study highlights the importance of controlling coating surface roughness and residual stress to enhance cohesion and provides valuable insights for developing advanced hard coatings.\u003c/p\u003e","manuscriptTitle":"The enhanced cohesive performance of magnetron sputtered Cr coatings on steel substrate via controlling columnar grain structures","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-08 12:41:36","doi":"10.21203/rs.3.rs-7263123/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-08-29T03:12:16+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-27T13:40:37+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-26T14:03:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"317359214086940313295118280580917238203","date":"2025-08-07T16:38:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"290126130154613212411816087158556044082","date":"2025-08-06T06:36:14+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-05T14:29:14+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-04T11:01:51+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-04T11:01:12+00:00","index":"","fulltext":""},{"type":"submitted","content":"Surface Science and Technology","date":"2025-07-31T13:57:47+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"surface-science-and-technology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Surface Science and Technology](https://link.springer.com/journal/44251)","snPcode":"44251","submissionUrl":"https://submission.springernature.com/new-submission/44251/3","title":"Surface Science and Technology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"85917bb3-e508-4342-8e24-6c5a198150ea","owner":[],"postedDate":"August 8th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-12-03T05:53:34+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-08 12:41:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7263123","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7263123","identity":"rs-7263123","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}