Eco-Friendly Fabrication of High-Performance Si3N4 Ceramic Substrates via Aqueous Tape Casting and Reaction-Bonding Sintering: Effects of α-Si3N4 Seeding

Eco-Friendly Fabrication of High-Performance Si3N4 Ceramic Substrates via Aqueous Tape Casting and Reaction-Bonding Sintering: Effects of α-Si3N4 Seeding | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Eco-Friendly Fabrication of High-Performance Si 3 N 4 Ceramic Substrates via Aqueous Tape Casting and Reaction-Bonding Sintering: Effects of α-Si 3 N 4 Seeding Yuan Liu, Yuanfei Liu, Jie Fu, Chengliang Ma This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6518304/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract This study presents a cost-effective and environmentally friendly approach for fabricating large-area, low-defect Si₃N₄ ceramic substrate materials using tape casting combined with reaction-bonding sintering at 1900°C. High-purity Si powder and a non-toxic Duramax™ B-1000 binder system were employed as raw materials. Orthogonal experiments (L9(3 4 ) array) optimized key parameters: 45 wt% solid content, 12.0 wt% binder, 0.4 wt% ammonium citrate dispersant, and a PEG-600 plasticizer to binder ratio (R) of 0.7. These conditions produced defect-free green tapes with smooth surfaces, minimal shrinkage, and balanced strength-flexibility properties. During re-sintering, the addition of 4 wt% Si 3 N 4 seeds maximized performance, yielding ceramics with 92.69% relative density, 15.6 GPa Vickers hardness, 6.6 MPa·m 1/2 fracture toughness, 636.1 MPa flexural strength, and 60.74 W·m − 1 ·K − 1 thermal conductivity. Microstructural analysis revealed elongated β-Si 3 N 4 grains, confirmed by XRD. This work demonstrates a scalable fabrication route for high-performance Si 3 N 4 substrates using economical and eco-conscious processing. silicon nitride ceramic substrates aqueous tape casting seed reaction-bonding sintering Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. Introduction With the expanding applications of electronic devices in energy storage, power transmission, and electric vehicles [ 1 , 2 ], the continuous increase in power density and integration level has led to significant heat generation in semiconductor chips [ 3 – 5 ]. Efficient thermal dissipation is critical, as excessive heat accumulation impairs device performance and may induce irreversible damage. Consequently, advanced ceramic substrates must simultaneously fulfill rigorous mechanical and thermal requirements to withstand demanding operational conditions. Silicon nitride (Si 3 N 4 ) ceramics demonstrate exceptional mechanical strength, outstanding chemical inertness, and superior thermal conductivity, making them ideal substrates for high-power electronic applications. However, several critical challenges limit the widespread adoption of Si 3 N 4 ceramic substrates: (1) the prohibitively high cost of high-purity Si 3 N 4 powders, (2) the significant gap between theoretical and experimentally achieved thermal conductivity values, (3) demanding application conditions, and (4) health hazards associated with organic processing agents. Recent advances in aqueous tape casting of low-cost, high-purity silicon powders have driven significant research interest in Si 3 N 4 ceramic fabrication, owing to their dual benefits of substantial cost reduction (40–60% lower than conventional Si 3 N 4 powder routes) and minimized environmental footprint by eliminating organic solvents. The synergistic combination of aqueous tape casting and subsequent reaction-bonded sintering enables economical manufacturing of dense Si 3 N 4 ceramics. Aqueous tape casting enables low-cost, environmentally friendly, and scalable manufacturing of ceramic substrates. In contrast, reaction-bonded sintering offers additional advantages[ 6 – 9 ], including: (1) cost reduction via cheaper Si powder (vs. pre-synthesized Si 3 N 4 ), (2) a 60% mass gain during nitridation, (3) machinability of reaction-bonded green bodies, and (4) dramatically reduced sintering shrinkage compared to conventional densification routes. While the direct nitridation of high-purity Si powder after tape casting is considered a viable processing route, the strongly exothermic Si-N reaction [ 10 ] risks localized Si melting, particularly in large-area, thin substrates (> 100 mm × 100 mm, ~ 0.32 mm thickness), often causing warping or cracking. To enable rapid nitridation while mitigating melting, optimized sintering temperatures, tailored Si particle sizes, or the addition of Si 3 N 4 diluent powders have been proposed [ 11 ]. Jin [ 12 ] demonstrated that incorporating 20–30% α/β-Si 3 N 4 diluent reduces the onset temperature of Si direct nitridation by ~ 200°C and suppresses molten-phase formation, yielding high-purity α- Si 3 N 4 (> 90%) with uniform microstructure. Oh [ 13 ] pioneered using the width of particle size distribution as a critical milling optimization parameter for waste silicon, achieving a 21% enhancement in SRBSN thermal conductivity while demonstrating that minimized sintering additives and optimized milling fluids synergistically improved material performance. Current research on Si 3 N 4 diluent-assisted direct nitridation of Si powder primarily focuses on optimizing powder synthesis processes [ 14 – 20 ]. However, the mechanistic influence of this critical parameter on the mechanical properties and thermal conductivity of Si 3 N 4 ceramic substrates fabricated via an integrated aqueous tape casting-reaction sintering approach remains systematically unexplored. This study employs a novel water-based binder system to systematically investigate the effects of solid loading and additive dosage on slurry rheology, identifying the optimal formulation. Building on this optimized system, we further elucidate the influence of Si 3 N 4 diluent content on the mechanical properties and thermal conductivity of reaction-sintered Si 3 N 4 ceramic substrates. 2. Experimental procedure The starting materials used in this study were Si powder (> 99.99%, D 50 = 1.61 µm, Hebei Metallurgical Powder Research Institute, China), MgO (> 98.5%, D 50 = 4.51 µm, Aladdin Biochemical Technology Co., Ltd., China), Y 2 O 3 (> 99.9%, D 50 = 6.40 µm, Sinopharm Chemical Reagent Beijing Co., Ltd., China), and α-Si 3 N 4 (> 99.9%, D 50 = 2.57 µm, North Star Precision Technology Co., China). The binder system consisted of Duramax™ B-1000 (Industrial use, Dow, USA), while ammonium citrate (grade 2, Aladdin Biochemical Technology Co., Ltd., China) and PEG-600 (grade 2, Aladdin Biochemical Technology Co., Ltd., China) served as the dispersant and plasticizer, respectively. In the tape casting process, the rheological behavior of the slurry directly determines the quality of green tape formation. Studies demonstrate that solid loading, dispersant addition, binder addition, and plasticizer/binder ratio (R-value) serve as critical parameters for regulating the slurry rheology. The experiment commenced by mixing ceramic powder with dispersant in deionized water, followed by 3.5 h ball milling to achieve a homogenously dispersed slurry system. Subsequent additions of binder and plasticizer were subjected to an additional 1.5 h ball milling to ensure compositional uniformity. After vacuum degassing (-0.01 MPa, 10 min), the slurry was cast under controlled conditions: doctor blade height of 0.3 mm and casting speed of 0.1 m/min. PET film was employed as the substrate material to facilitate tape release. A gradient drying protocol (30°C → 50°C → 70°C → 50°C) effectively prevented cracking and warping caused by rapid solvent evaporation. The dried green tapes were precision-cut and laminated at 120°C under 3.0 T pressure for 10 min to ensure optimal interlayer bonding. Finally, the binder burnout and nitridation sintering processes yielded high-performance ceramic products. During the heat treatment, the debinding step is carried out first by heating the sample from room temperature to 550°C at a ramp rate of 1°C/min, followed by a 2 h holding time to ensure complete decomposition and removal of organic additives, thereby preventing contamination in subsequent sintering. Subsequently, the nitridation reaction is performed under a nitrogen atmosphere, where the temperature is raised to 1350°C at 10°C/min and held for 3 h to achieve a high conversion rate of Si powder into the Si 3 N 4 phase. Finally, the temperature is further increased to 1900°C with a 2 h sintering step to ensure full densification of the ceramic substrate. The theoretical density of the material was calculated using the rule of mixtures, while the experimental density was determined by the Archimedes principle method. Flexural strength measurements were performed using three-point bending tests (ASTM D790) with rectangular specimens (3 mm × 4 mm × 36 mm). The tests were conducted at a span length of 30 mm and a crosshead speed of 0.5 mm/min using a WHY-300/10 universal testing machine (Shanghai Hualong Test Instruments Co., Ltd., China). Vickers hardness was measured in compliance with GB/T 16534 − 2009 standard using a 401MVD microhardness tester (Wolpert, USA) under an applied load of 49 N with a 15 s holding time. Fracture toughness was evaluated by analyzing the indentation-induced crack patterns following standard procedures. Phase composition analysis was conducted using a Philips X’pert Pro X-ray diffractometer (XRD) with Cu-Kα radiation (λ = 1.5406 Å) operated at 40 kV and 30 mA. The diffraction patterns were collected over a 2θ range of 10° to 80° with a step size of 0.013° and a scanning speed of 0.33°/s. Thermal diffusivity was measured following ASTM E1461-2013 standard using the laser flash method on an LFA 457 laser thermal analyzer (Netzsch, Germany). Disk-shaped specimens with a diameter of 12.7 mm and a thickness of 3 mm were prepared for the measurements. The thermal conductivity ( \(\:k\) ) was calculated from the measured thermal diffusivity ( \(\:\alpha\:\) ), bulk density ( \(\:\rho\:\) ) and specific heat capacity ( \(\:{C}_{p}\) ) using the relationship \(\:k=\rho\:{C}_{p}\alpha\:\) . Microstructural characterization was performed using a field-emission scanning electron microscope (FE-SEM, Zeiss Sigma 300, Germany) to examine both the fracture surfaces and microstructure of the specimens. 3. Results and discussion 3.1 Effects of solid loading and additives on tape-casting slurry and green body properties The rheological behavior of ceramic slurries critically determines the quality of tape-cast silicon green sheets, particularly their thickness uniformity, surface roughness, and microstructural homogeneity. This study demonstrates that slurry rheology, controlled by the synergistic interactions among dispersant, binder, and plasticizer additives, is the primary factor governing the final ceramic performance. As shown in Fig. 1 (a), the Si slurry demonstrates pronounced shear-thinning behavior throughout the entire measurement range, making it particularly suitable for tape-casting applications At low shear rates, the high viscosity effectively suppresses particle agglomeration and sedimentation, ensuring colloidal stability. Conversely, the viscosity sharply decreases (η 20 s − 1 ) under high-shear conditions, facilitating uniform slurry flow during the actual casting process. This pseudoplastic behavior enhances dispersion homogeneity and dimensional control in the formed tapes. Notably, the slurry viscosity exhibits an exponential increase with solid loading, indicating strong particle-particle interactions at elevated filler fractions. As shown in Fig. 1 (b), the slurry viscosity decreases progressively with increasing dispersant (ammonium citrate) concentration, demonstrating its effectiveness in enhancing fluidity. This rheological improvement stems from ammonium citrate’s ability to disrupt interparticle bonding forces, promoting homogeneous dispersion. Through pH-dependent ionization (e.g., NH 4 + and citrate 3− dissociation), the dispersant generates electrostatic repulsion between charged particle surfaces, effectively mitigating agglomeration and stabilizing the suspension system. As illustrated in Fig. 1 (c), the addition of Duramax™ B-1000 induces a non-monotonic variation in slurry viscosity, characterized by an initial decrease followed by a slight increase and subsequent reduction. Importantly, the overall change in viscosity remains relatively small. This commercially available aqueous emulsion offers distinct advantages for tape-casting applications: (1) exceptionally low foam generation during processing, (2) remarkable insensitivity to ambient humidity variations, representing a critical improvement over conventional water-based binders, and (3) facilitation of high solid loading formulations due to its intrinsically low viscosity. As shown in Fig. 1 (d), the slurry viscosity exhibits a non-monotonic dependence on the plasticizer-to-binder ratio (R), initially increasing before decreasing. Unlike conventional long-chain polymers that depend on high molecular weight and extended linear segments for strong physical networks, Duramax™ B-1000 exhibits resin-like polymer behavior. To achieve green bodies with high strength while maintaining flexibility, an optimal plasticizer addition is required. The plasticizer lubricates the binder chains, preventing excessive crosslinking and promoting chain coiling, thereby enhancing deformability. However, excessive plasticizer concentration can impair processability by increasing slurry viscosity due to disrupted polymer-solvent interactions. Figure 2 (a) demonstrates that the slurry viscosity increases with rising solid content at a shear rate of 20 s − 1 , showing a nonlinear rheological response. A dramatic viscosity enhancement occurs when the solid loading exceeds 50 wt%, indicating a critical transition in the suspension behavior. Previous studies [ 21 ] have established that an optimal viscosity range of 0.2-1 Pa·s is essential for aqueous tape casting: slurries with viscosity below 0.2 Pa·s tend to form cracks during drying due to excessive fluidity, while those exceeding 1 Pa·s lose self-leveling capability, resulting in uneven tape surfaces. Based on this rheological analysis, solid loadings of 40 wt%, 45 wt%, and 50 wt% were systematically selected as experimental variables for subsequent orthogonal testing to investigate formulation-performance relationships. Figure 2 (b) reveals a pronounced decrease in system viscosity as the dispersant concentration increases from 0.2 wt% to 1.4 wt%, with the most significant viscosity reduction occurring at 0.8 wt% dispersant addition. This observation demonstrates the crucial role of dispersant in optimizing the rheological properties of the slurry. While a maximum dispersant loading of 1.4 wt% achieves the lowest viscosity, the formulation of tape-casting slurries requires comprehensive consideration of various factors, particularly the influence of organic additives on green-body density and subsequent debinding behavior. Excessive dispersant content not only compromises the green density but may also induce defects during the debinding process. Based on these considerations, dispersant concentrations of 0.6 wt%, 0.8 wt%, and 1.0 wt% were carefully selected as experimental parameters for systematic investigation The rheological behavior exhibits distinct concentration-dependent characteristics at a shear rate of 20 s − 1 (Fig. 2 c). The slurry viscosity demonstrates remarkable stability within the 6.0–10.0 wt% Duramax™ B-1000 concentration range. A pronounced viscosity increase emerges when the binder content rises from 10.0 to 12.0 wt%, followed by a subsequent non-monotonic transition featuring an initial decrease and subsequent increase across the 12.0–18.0 wt% range. Duramax™ B-1000, as an environmentally benign emulsion binder, simultaneously enhances mechanical strength and structural flexibility in ceramic systems. In tape casting applications, insufficient binder content ( 14.0 wt%) induces debinding complications and reduces attainable solid loading. Consequently, the binder concentration should be minimized while meeting mechanical requirements. Based on these considerations, the experimental matrix incorporates 10.0 wt%, 12.0 wt%, and 14.0 wt% Duramax™ B-1000 concentrations, representing critical transition points in the rheological profile while balancing processing requirements and product performance. The rheological behavior at a shear rate of 20 s − 1 (Fig. 2 d) reveals a characteristic non-monotonic viscosity response to increasing R values. This trend suggests distinct structural transitions occurring within the slurry system as the PEG-600 content varies. At lower R values (R < 0.7), the amphiphilic nature of PEG-600 enables effective particle dispersion and boundary lubrication, thereby reducing interparticle friction and decreasing the overall viscosity. As the R value increases to intermediate levels (0.7 < R < 1.1), competitive physical interactions between PEG-600 and the polymeric binder become predominant, potentially involving hydrogen bonding with hydroxyl groups, dipole-dipole interactions with polar moieties, and temporary physical entanglement of polymer chains. These interactions may generate transient network structures that increase the system's resistance to shear flow. However, at higher R values (R > 1.1), the additional PEG-600 molecules act primarily as plasticizers, disrupting the established polymer network through excessive dilution and weakening the intermolecular associations, ultimately leading to viscosity reduction. Three representative R values (0.7, 0.9, and 1.1) were selected to systematically investigate these competing mechanisms. The 0.7 ratio represents the threshold where surface effects transition to bulk interactions, 0.9 corresponds to the potential maximum in network formation, while 1.1 indicates the onset of network destabilization. The factors and their levels (solid content, dispersant addition, binder addition, and R-value) chosen for the orthogonal experiments are summarized in Table 1 . Table 1 The various quantities (wt.%) used for the orthogonal experiments group solid content (A) dispersant addition (B) binder addition (C) R value (D) 1 40 0.4 10 0.7 2 45 0.6 12 0.9 3 50 0.8 14 1.1 The orthogonal test design and experimental results are presented in Table 2 . In the orthogonal experiment, the effects of four factors on the maximum tensile strength, elongation at break, thickness reduction, and density were comprehensively analyzed. The optimal experimental conditions were determined as follows: solid content 45 wt%, ammonium citrate addition 0.4 wt%, Duramax™ B-1000 binder addition 12.0 wt%, and R-value 0.7. This formulation effectively balances key performance indicators, including maximum tensile strength, elongation at break, thickness shrinkage, and density. Based on these findings, the subsequent preparation process of ceramic substrates was further optimized. Table 2 The orthogonal test protocol and experimental results Specimen Ultimate tensile strength (MPa) Fracture elongation (%) Thickness shrinkage (%) Density (g/cm 3 ) 1 0.2054 8.93 51.34 1.27 2 0.2380 37.22 55.04 1.29 3 0.0927 36.88 58.97 1.34 4 0.5474 25.61 50.50 1.40 5 0.3146 64.08 50.71 1.38 6 0.2814 13.00 46.01 1.31 7 0.2307 3.66 39.53 1.32 8 0.2821 4.22 34.76 1.28 9 0.3308 8.20 38.67 1.29 3.2 Influence of seed addition amount Based on optimized processing parameters, high-purity fine Si powder and α-Si 3 N 4 powder were used as starting materials with a Y 2 O 3 -MgO binary additive system. The sintering additives were proportioned according to the stoichiometric ratio (Si 3 N 4 : Y 2 O 3 : MgO = 93 mol%: 2 mol%: 5 mol%) calculated for complete silicon nitridation. Six comparative experimental groups were designed as presented in Table 3 . Table 3 Experimental formulations with varying additions of Si 3 N 4 seeds Specimen Nitrided Si (mol%) Y 2 O 3 (mol%) MgO (mol%) α-Si 3 N 4 (mol%) S0 93 2 5 0 S1 91 2 5 2 S2 89 2 5 4 S3 87 2 5 6 S4 85 2 5 8 S5 83 2 5 10 Figure 3 shows the XRD patterns of samples with different Si 3 N 4 seed contents after re-sintering at 1900 ℃ for 2 h. All samples exhibit diffraction peaks of β-Si 3 N 4 and YMgSi 2 O 5 N 2 , while S4 and S5 display weak Si 2 N 2 O peaks. After re-sintering, the β-Si 3 N 4 peak intensities increase, and all α-Si 3 N 4 peaks disappear, confirming complete α→β phase transformation. No SiO 2 peaks are detected due to (1) the formation of amorphous grain-boundary glass phases and (2) partial SiO 2 volatilization at high temperatures. The reaction follows: \(\:3Si+2{N}_{2}\to\:{Si}_{3}{N}_{4}\) (4.1) \(\:Si{O}_{2}+2{N}_{2}+3Si\to\:2{Si}_{2}{N}_{2}O\) (4.2) \(\:Si{O}_{2}+{Si}_{3}{N}_{4}\to\:2{Si}_{2}{N}_{2}O\) (4.3) \(\:2MgO+Si{O}_{2}\to\:{Mg}_{2}Si{O}_{4}\) (4.4) \(\:{Mg}_{2}Si{O}_{4}+Si{O}_{2}\to\:2MgSi{O}_{3}\) (4.5) \(\:3{Si}_{3}{N}_{4}+{Y}_{2}{O}_{3}+3MgSi{O}_{3}\to\:2YMg{Si}_{2}{O}_{5}{N}_{2}+3Si{O}_{2}\) (4.7) Figure 4 clearly demonstrates the effect of Si 3 N 4 seed content on the growth of β-Si 3 N 4 grains. Samples S0 through S5 all display elongated rod-like β-Si 3 N 4 grains. As the Si 3 N 4 seed content increases from 0 wt% to 6 wt%, a gradual increase in the aspect ratio of β-Si 3 N 4 grains is observed. Sample S0 (0 wt% seeds) contains only short, stubby β-Si 3 N 4 grains with relatively large pores. With increasing seed content in samples S1 and S2, both the proportion of high-aspect-ratio β-Si 3 N 4 grains and the pore reduction become more pronounced. However, when seed content increases beyond 6 wt% up to 10 wt%, the aspect ratio of β-Si 3 N 4 grains begins to decrease progressively. Correspondingly, samples S3, S4 and S5 show increasing proportions of shorter β-Si 3 N 4 grains along with gradually enlarged pore structures. With increasing Si 3 N 4 seed content, the grain packing density first increases and then decreases. The seeds serve as heterogeneous nucleation sites during nitridation, significantly lowering the activation energy for Si powder nitridation and promoting the conversion of Si to Si 3 N 4 . This facilitates particle rearrangement and liquid-phase mass transport, which benefits densification and grain growth during resintering. However, excessive seed content causes particle agglomeration and uneven distribution, leading to non-uniform nitridation and pore formation. These defects subsequently impede densification and hinder uniform grain growth during resintering. Figure 5 shows the density of resintered samples with varying Si 3 N 4 seed content. All samples exhibit relative densities exceeding 77%. When the seed content increases from 0 to 4 wt%, the density of Si 3 N 4 gradually rises, reaching a maximum relative density of 92.69% at 4 wt% seed addition. The seeds act as heterogeneous nucleation sites during the nitridation reaction, significantly reducing the activation energy for Si powder nitridation and promoting the conversion of Si into Si 3 N 4 . This facilitates particle rearrangement and liquid-phase mass transport during nitridation, benefiting subsequent densification and grain growth in the sintering stage. However, when the seed content further increases to 4–10 wt%, the density gradually decreases. Excessive Si 3 N 4 seed addition triggers elongated β-Si 3 N 4 grain growth, leading to coarse, interlocked microstructures. This inhibits liquid-phase flow and traps residual pores, reducing densification. The primary driving force for densification stems from capillary forces during particle rearrangement in the liquid phase. Therefore, variations in additive content influence liquid-phase formation, significantly affecting the final densification of Si 3 N 4 materials. Figure 6 shows the hardness of resintered samples with different Si 3 N 4 seed additions. The sample hardness first increases then decreases with increasing seed content, reaching a maximum value of 15.60 GPa at 4 wt% seed addition. When the seed content is below 4 wt%, the hardness increases progressively with higher seed content as the enhanced densification and refined microstructure strengthen the material. However, exceeding 4 wt% seed addition leads to decreased hardness. This deterioration results from reduced densification caused by impurities introduced from excessive seeds and the formation of overgrown β-Si 3 N 4 columnar grains. These elongated grains become interlocked, inhibiting liquid phase flow during sintering and increasing residual porosity, ultimately lowering the material hardness. The hardness evolution correlates directly with the density changes observed in Fig. 5 , demonstrating the critical balance in seed addition for optimal Si 3 N 4 ceramic performance. Figure 7 shows the fracture toughness and flexural strength of resintered samples with varying Si 3 N 4 seed content. The fracture toughness first increases then decreases with increasing seed content, peaking at 6.6 MPa·m 1/2 for 4wt% seeds, which aligns with the concurrent maxima in density and hardness. At seed contents below 4wt%, increasing amounts introduce more β-Si 3 N 4 grains with high aspect ratios. These elongated grains create a self-toughening effect through crack deflection and bridging mechanisms that effectively hinder crack propagation. Examination of the fracture surfaces reveals these reinforcing grains progressively dominate the microstructure, improving toughness up to the optimal 4wt% level. Exceeding the 4wt% seed threshold triggers a series of microstructural degradations: β-Si 3 N 4 grains progressively lose their elongated morphology, accompanied by a declining population of high-aspect-ratio grains. Concurrently, enlarged pores and coarsened cracks emerge throughout the matrix, collectively undermining the material's crack resistance capability. These microstructural degradations combine to significantly reduce the material's resistance to crack propagation, leading to the observed decline in fracture toughness. The results demonstrate how the balance between grain morphology and defect formation dictates the mechanical performance of seeded Si 3 N 4 ceramics. Flexural strength exhibited a positive correlation with sample density, showing a significant improvement with increasing density. Specimen S2 achieved the maximum flexural strength of 636.1 MPa, approaching the requirements for engineering applications. The enhanced densification contributed to reduced porosity, increased effective load-bearing area, and suppressed stress concentration, thereby strengthening the material. However, when the Si 3 N 4 seed content increased from 4 wt% to 10 wt%, porosity rose, leading to decreased densification and abnormal grain coarsening, which ultimately degraded flexural strength. In summary, an optimal Si 3 N 4 seed content (4 wt%) enhances both fracture toughness and flexural strength, whereas exceeding this threshold results in increased porosity and non-uniform grain growth, compromising mechanical performance. As shown in Fig. 8 , the thermal conductivity of Si 3 N 4 ceramics exhibited a maximum (60.74 W·m − 1 ·K − 1 in S2) with increasing seed content, attributable to microstructural modifications. Optimal seed addition promoted aligned β-Si 3 N 4 grains with high aspect ratios while suppressing porosity through improved particle packing during sintering. These microstructural refinements enhanced phonon transport by reducing pore-related scattering centers. Simultaneously, sintering additives effectively lowered oxygen impurity concentrations, further minimizing lattice defect scattering. The critical Y 2 O 3 /SiO 2 ratio governed oxygen solubility in the liquid sintering phase. Excessive seeding (> 4 wt%) introduced supplementary SiO 2 , destabilizing this ratio and compromising oxygen scavenging capacity. This mechanism accounts for the observed thermal conductivity reduction at higher seed contents (4–10 wt%), where diminished Y 2 O 3 effectiveness permitted residual oxygen impurities to persist as phonon scattering sites[ 22 ]. The mechanical and thermal properties of the resintered samples exhibited an initial increase followed by a subsequent decrease with increasing Si 3 N 4 seed content. Optimal performance was achieved at 4 wt% seed addition, where the relative density, Vickers hardness, fracture toughness, flexural strength, and thermal conductivity reached 92.69%, 15.6 GPa, 6.6 MPa·m 1/2 , 636.1 MPa, and 60.74 W·m − 1 ·K − 1 , respectively. Microstructural analysis of the fracture surfaces revealed a predominant population of high-aspect-ratio β-Si 3 N 4 grains under these optimized conditions. 4. Conclusions This work employed a tape-casting combined with reaction-bonding sintering approach to fabricate Si 3 N 4 ceramic substrate materials at 1900°C, using cost-effective raw materials (high-purity Si powder) and an environmentally friendly Duramax™ B-1000 binder system. Through orthogonal experiments, the optimal processing parameters for producing large-area, low-defect silicon green tapes were systematically investigated. The mechanical and thermal properties of the re-sintered ceramics prepared from these optimized green tapes were subsequently characterized. The main conclusions can be summarized as follows: (1) This study employed non-toxic Duramax™ B-1000 as the binder for preparing silicon green tapes via tape casting. Multiple parameters significantly influenced both the slurry rheology and the performance of dried tapes, including: solid content (45 wt%), Duramax™ B-1000 addition (12.0 wt%), ammonium citrate dispersant addition (0.4 wt%), and the PEG-600 plasticizer to binder ratio (R = 0.7). Through a designed L9(3 4 ) orthogonal array of 9 experimental groups, the optimal processing window was identified. The resulting green tapes exhibited smooth defect-free surfaces, minimal shrinkage, and balanced mechanical strength with flexibility. (2) During re-sintering, increasing Si 3 N 4 seed content initially enhanced material performance before declining beyond an optimal point. Samples with 4 wt% seed additions achieved 92.69% relative density, 15.6 GPa Vickers hardness, 6.6 MPa·m 1/2 fracture toughness, 636.1 MPa flexural strength, and 60.74 W·m − 1 ·K − 1 thermal conductivity. Microstructural analysis showed predominantly elongated β-Si 3 N 4 grains with corresponding diffraction peaks in XRD patterns. Declarations Competing Interests The authors have no relevant financial or non-financial interests to disclose. Funding This work was supported by the National Natural Science Foundation of China (No. 51872265, No. 51902290), Collaborative Innovation Major Special Project of Zhengzhou (No. 20XTZX12025) and Program for Leading Talents of Science and Technology in the Central Plain of China 2022 (No. 234200510002). The authors would like to thank the above for their support. Author Contribution Yuan Liu: Experimental Design, Experimental Operation, Data Analysis and Organization, Literature Survey, Writing -original draftYuanfei Liu: Experimental operation, data arrangement and analysis, literature surveyJie Fu: Data organization and analysis, literature surveyChengliang Ma: Resources, Writing - review & editing, Supervision Acknowledgments This work was supported by the National Natural Science Foundation of China (No. 51872265, No. 51902290), Collaborative Innovation Major Special Project of Zhengzhou (No. 20XTZX12025) and Program for Leading Talents of Science and Technology in the Central Plain of China 2022 (No. 234200510002). The authors would like to thank the above for their support. References Jr.C.R. Eddy, D.K. Gaskill, Silicon carbide as a platform for power electronics, Science. 324 (5933) (2009) 1398-1400, https://www.science.org/doi/10.1126/science.1168704. Y. Zhou, H. Hyuga, D. Kusano, Y.I Yoshizawa, T. Ohji, K. Hirao, Development of high-thermal-conductivity silicon nitride ceramics, J. Asian Ceram. Soc. 3 (3) (2015) 221-229, https://doi.org/10.1016/j.jascer.2015.03.003. C. Buttay, D. Planson, B. Allard, D. Bergogne, P. Bevilacqua, C. Joubert, M. Lazar, C. Martin, H. Morel, D. Tournier, C. Raynaud, State of the art of high temperature power electronics, Mater. Sci. Eng. B 176 (4) (2011) 283-288, https://doi.org/10.1016/j.mseb.2010.10.003. F. Hu, Z.P. Xie, J. Zhang, Z.L. Hu, D. An, Promising high-thermal-conductivity substrate material for high-power electronic device: silicon nitride ceramics, Rare Met. 39 (2020) 463-478, https://doi.org/10.1007/s12598-020-01376-7. C.C. Ye, H.Q. Ru, C.P. Zhang, W. Wang, D.L. Chen, Fracture toughness of Si 3 N 4 ceramic composites: Effect of texture, J. Eur. Ceram. Soc. 41 (13) (2021) 6346-6355, https://doi.org/10.1016/j.jeurceramsoc.2021.06.008. X. Zhu, Y. Zhou, K. Hirao, Z. Lenčéš, Processing and thermal conductivity of sintered reaction‐bonded silicon nitride. I: effect of Si powder characteristics, J. Am. Ceram. 89 (11) (2006) 3331-3339, https://doi.org/10.1111/j.1551-2916.2006.01195.x. Y. Zhou, H. Hyuga, D. Kusano, Y.I. Yoshizawa, K. Hirao, A tough silicon nitride ceramic with high thermal conductivity, Adv. Mater. 39 (23) (2011) 4563-4567, https://doi.org/10.1002/adma.201102462. Y.S. Li, H.N. Kim, H.B. Wu, M.J. Kim, J.W. Ko, J.M.Y. Kim, Y.J. Park, Z.R. Huang, H.D. Kim, Improved thermal conductivity of sintered reaction-bonded silicon nitride using a BN/graphite powder bed, J. Eur. Ceram. Soc. 37 (15) (2017) 4483-4490, https://doi.org/10.1016/j.jeurceramsoc.2017.05.045. Y. Zhou, H. Hyuga, D. Kusano, M. Chika, H. Kiyoshi, Effects of yttria and magnesia on densification and thermal conductivity of sintered reaction‐bonded silicon nitrides, J. Am. Ceram. 102 (4) (2019) 1579-1588, https://doi.org/10.1111/jace.16015. T. Wakihara, M. Yabuki, J. Tatami, K. Komeya, T. Meguro, H. Kita, N. Kondo, K. Hirao, Effect of diluents on post-reaction sintering of silicon nitride ceramics, Key Eng. Mater. 352 (2007) 185-188, https://doi.org/10.4028/www.scientific.net/KEM.352.185. J.J. Yu, W.M. Guo, L.Y. Zeng, H.T. Lin, Effect of SiO 2 addition on Si 3 N 4 ceramics prepared by rapid nitridation and post-sintering route, Ceram. Int. 43 (16) (2017) 13901-13906, https://doi.org/10.1016/j.ceramint.2017.07.116. X. Jin, P.F. Xing, Y.X. Zhuang, J. Kong, S.N. Jiang, D.H. Wei, Effect of Si 3 N 4 diluent on direct nitridation of silicon powder, Ceram. Int. 45 (8) (2019) 10943-10950, https://doi.org/10.1016/j.ceramint.2019.02.175. H.M. Oh, H.K. Lee, Controlling the width of particle size distribution of Si powder and properties of sintered reaction-bonded silicon nitride (SRBSN) ceramics with high thermal conductivity, Ceram. Int. 46 (8) (2020) 12517-12524, https://doi.org/10.1016/j.ceramint.2020.02.014. H. Hyuga, N. Kondo, H. Kita, Fabrication of dense β‐SiAlON ceramics with ZrO 2 additions via a rapid reaction‐bonding and postsintering route, J. Am. Ceram. 94 (4) (2011) 1014-1018, https://doi.org/10.1111/j.1551-2916.2010.04192.x. H. Hyuga, Y. Zhou, D. Kusano, K. Hirao, H. Kita, Nitridation behaviors of silicon powder doped with various rare earth oxides, J. Ceram. Soc. Jpn. 119 (1387) (2011) 251-253, https://doi.org/10.2109/jcersj2.119.251. B.R. Golla, J.W. Ko, J.M. Kim, H.D. Kim, Effect of particle size and oxygen content of Si on processing, microstructure and thermal conductivity of sintered reaction bonded Si 3 N 4 , J. Alloys Compd. 595 (2014) 60-66, https://doi.org/10.1016/j.jallcom.2014.01.131. Y. Zhou, T. Ohji, H. Hyuga, Y.C. Yoshizawa, N. Murayama, K. Hirao Fracture resistance behavior of high‐thermal‐conductivity silicon nitride ceramics, Int. J. Appl. Ceram. Technol. 11(5) (2014) 872-882, https://doi.org/10.1111/ijac.12109. W.M. Guo, L.X. Wu, H. Xie, Y. You, H.T. Lin, Effect of TiO 2 additives on nitridation of Si powders, Mater. Lett. 177 (2016) 61-63, https://doi.org/10.1016/j.matlet.2016.04.129. F.W. Chang, T.H. Liou, F.M. Tsai, The nitridation kinetics of silicon powder compacts, Thermochim. Acta 354 (1-2) (2000) 71-80, https://doi.org/10.1016/S0040-6031(00)00432-9. M. Müller, W. Bauer, R. Knitter, Processing of micro-components made of sintered reaction-bonded silicon nitride (SRBSN). Part 1: Factors influencing the reaction-bonding process, Ceram. Int. 35 (7) (2009) 2577-2585, https://doi.org/10.1016/j.ceramint.2009.02.013. J. Wang, L. Gao, Surface and electrokinetic properties of Y-TZP suspensions stabilized by polyelectrolytes, Ceram. Int. 26 (2) (2000) 187-191, https://doi.org/10.1016/S0272-8842(99)00038-3. X. Jin, P. Xing, Y. Zhuang, J. Kong, S.N. Jiang, D.H. Wei, Function mechanism of Y 2 O 3 additive in silicon powder nitridation, Int. J. Appl. Ceram. Technol. 16 (4) (2019) 1407-1415, https://doi.org/10.1111/ijac.13207. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 13 Jun, 2025 Reviews received at journal 27 May, 2025 Reviews received at journal 24 May, 2025 Reviewers agreed at journal 18 May, 2025 Reviewers agreed at journal 17 May, 2025 Reviewers agreed at journal 17 May, 2025 Reviewers invited by journal 15 May, 2025 Editor assigned by journal 13 May, 2025 Submission checks completed at journal 13 May, 2025 First submitted to journal 24 Apr, 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-6518304","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":458224533,"identity":"bdf32e22-cdce-4ede-9d96-5223fed0d75a","order_by":0,"name":"Yuan Liu","email":"","orcid":"","institution":"Zhengzhou University","correspondingAuthor":false,"prefix":"","firstName":"Yuan","middleName":"","lastName":"Liu","suffix":""},{"id":458224536,"identity":"67caaa3e-5d42-4ee7-8b90-c47e3dec0bf6","order_by":1,"name":"Yuanfei Liu","email":"","orcid":"","institution":"Zhengzhou University","correspondingAuthor":false,"prefix":"","firstName":"Yuanfei","middleName":"","lastName":"Liu","suffix":""},{"id":458224538,"identity":"8376fcfc-6dde-4b91-9e7d-e99890cb26ba","order_by":2,"name":"Jie Fu","email":"","orcid":"","institution":"Henan North Star Precision Technology Company Limited","correspondingAuthor":false,"prefix":"","firstName":"Jie","middleName":"","lastName":"Fu","suffix":""},{"id":458224542,"identity":"567303a1-04c5-48db-88fe-a936c401a7da","order_by":3,"name":"Chengliang Ma","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+ElEQVRIiWNgGAWjYHACNhAhAyY/QEQMiNLCAyIZZ5CkBUQw8xCjRbf98LMHH3fU8vCxnz382uZPXWIDe/M2CYaaOzi1mJ1JMzeceeY4DxtPXpp1Dg9bYgPPsTIJhmPPcGs5kMMmzdt2DOiXHDPjHAmexAaJHDMJxobDuLWcf8Mm/Rekhf+NmbGFgURig/wbAlpuAG1hbKvhYZPIMX7MkGAAtIWHkJZnZpK9bQeAWt6YMfYcSDBu40krtkg4hs9hyc8kfrbVycn35xh/+PGnTraf/fDGGx9qcGuBArACNgkwCSISCGlgYKgDEcwfCCscBaNgFIyCkQgA/hFNwyX3z+sAAAAASUVORK5CYII=","orcid":"","institution":"Zhengzhou University","correspondingAuthor":true,"prefix":"","firstName":"Chengliang","middleName":"","lastName":"Ma","suffix":""}],"badges":[],"createdAt":"2025-04-24 07:38:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6518304/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6518304/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83135220,"identity":"e7db0531-feab-4147-95e4-0f111e5109f9","added_by":"auto","created_at":"2025-05-20 11:13:25","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":185400,"visible":true,"origin":"","legend":"\u003cp\u003eSlurry viscosity as a function of shear rate: (a) Viscosity profiles at different solid contents; (b) Viscosity variation with dispersant addition; (c) Viscosity dependence on binder addition; (d) Viscosity behavior under different R-values\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6518304/v1/edbeaaf71ac9d51e73d0c83e.png"},{"id":83135219,"identity":"124174d9-2a09-454c-8ba2-fcc912d7dc48","added_by":"auto","created_at":"2025-05-20 11:13:25","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":92826,"visible":true,"origin":"","legend":"\u003cp\u003eViscosity dependence on composition at 20 s\u003csup\u003e-1\u003c/sup\u003e shear rate: (a) Effect of solid content; (b) Effect of dispersant addition; (b) Effect of binder addition; (d) Effect of R-value\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6518304/v1/da4ba385c44f382fb5da8304.png"},{"id":83135222,"identity":"31ae0d6b-82ee-470c-b684-beb7b6e39e78","added_by":"auto","created_at":"2025-05-20 11:13:25","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":38156,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of the samples with different Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed additions after re-sintering\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6518304/v1/ea18de4f3cff7f1e6c5cd8b0.png"},{"id":83136806,"identity":"b89dbfb5-814f-402b-9f9b-e5e8bceba353","added_by":"auto","created_at":"2025-05-20 11:29:25","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":482048,"visible":true,"origin":"","legend":"\u003cp\u003eCross-sectional microstructure of the samples after re-sintering with different Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed additions: (a) S0; (b) S1; (c) S2; (d) S3; (e) S4; (f) S5\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6518304/v1/c3d01197498d5d30c813de6f.png"},{"id":83135223,"identity":"5d690aed-ba9a-417d-bcda-83cffccb5210","added_by":"auto","created_at":"2025-05-20 11:13:25","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":29775,"visible":true,"origin":"","legend":"\u003cp\u003eDensity of the samples after re-sintering with different Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed additions\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6518304/v1/f93f1246f1df9e375ac68583.png"},{"id":83137160,"identity":"62d280ce-3b7f-4469-8567-495a1d531526","added_by":"auto","created_at":"2025-05-20 11:37:25","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":15001,"visible":true,"origin":"","legend":"\u003cp\u003eHardness of the samples after re-sintering with different Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed additions\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6518304/v1/eb8122b42979cf806c6bfe5d.png"},{"id":83135231,"identity":"0b673e9b-d93c-473a-9bef-be074599d07b","added_by":"auto","created_at":"2025-05-20 11:13:25","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":31163,"visible":true,"origin":"","legend":"\u003cp\u003eFracture toughness and flexural strength of samples after re-sintering with different Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed additions\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6518304/v1/4b5f4a8043a3bfc38985ee8e.png"},{"id":83137159,"identity":"0a40f65e-23d4-4169-b050-10b42a6edbf4","added_by":"auto","created_at":"2025-05-20 11:37:25","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":34903,"visible":true,"origin":"","legend":"\u003cp\u003eThermal conductivity of samples after re-sintering with different Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed additions\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-6518304/v1/695dd9eb780fe0553647835f.png"},{"id":83138261,"identity":"dfa3a76e-f0ca-4d5e-9ec6-4b2967fa333c","added_by":"auto","created_at":"2025-05-20 11:45:26","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1680801,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6518304/v1/656889fa-45d9-475c-8dc7-99072b0437e5.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eEco-Friendly Fabrication of High-Performance Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e Ceramic Substrates via Aqueous Tape Casting and Reaction-Bonding Sintering: Effects of α-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e Seeding\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eWith the expanding applications of electronic devices in energy storage, power transmission, and electric vehicles [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], the continuous increase in power density and integration level has led to significant heat generation in semiconductor chips [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Efficient thermal dissipation is critical, as excessive heat accumulation impairs device performance and may induce irreversible damage. Consequently, advanced ceramic substrates must simultaneously fulfill rigorous mechanical and thermal requirements to withstand demanding operational conditions.\u003c/p\u003e \u003cp\u003eSilicon nitride (Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e) ceramics demonstrate exceptional mechanical strength, outstanding chemical inertness, and superior thermal conductivity, making them ideal substrates for high-power electronic applications. However, several critical challenges limit the widespread adoption of Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e ceramic substrates: (1) the prohibitively high cost of high-purity Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e powders, (2) the significant gap between theoretical and experimentally achieved thermal conductivity values, (3) demanding application conditions, and (4) health hazards associated with organic processing agents. Recent advances in aqueous tape casting of low-cost, high-purity silicon powders have driven significant research interest in Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e ceramic fabrication, owing to their dual benefits of substantial cost reduction (40\u0026ndash;60% lower than conventional Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e powder routes) and minimized environmental footprint by eliminating organic solvents. The synergistic combination of aqueous tape casting and subsequent reaction-bonded sintering enables economical manufacturing of dense Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e ceramics. Aqueous tape casting enables low-cost, environmentally friendly, and scalable manufacturing of ceramic substrates. In contrast, reaction-bonded sintering offers additional advantages[\u003cspan additionalcitationids=\"CR7 CR8\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], including: (1) cost reduction via cheaper Si powder (vs. pre-synthesized Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e), (2) a 60% mass gain during nitridation, (3) machinability of reaction-bonded green bodies, and (4) dramatically reduced sintering shrinkage compared to conventional densification routes.\u003c/p\u003e \u003cp\u003eWhile the direct nitridation of high-purity Si powder after tape casting is considered a viable processing route, the strongly exothermic Si-N reaction [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] risks localized Si melting, particularly in large-area, thin substrates (\u0026gt;\u0026thinsp;100 mm \u0026times; 100 mm, ~\u0026thinsp;0.32 mm thickness), often causing warping or cracking. To enable rapid nitridation while mitigating melting, optimized sintering temperatures, tailored Si particle sizes, or the addition of Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e diluent powders have been proposed [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Jin [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] demonstrated that incorporating 20\u0026ndash;30% α/β-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e diluent reduces the onset temperature of Si direct nitridation by ~\u0026thinsp;200\u0026deg;C and suppresses molten-phase formation, yielding high-purity α- Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e (\u0026gt;\u0026thinsp;90%) with uniform microstructure. Oh [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] pioneered using the width of particle size distribution as a critical milling optimization parameter for waste silicon, achieving a 21% enhancement in SRBSN thermal conductivity while demonstrating that minimized sintering additives and optimized milling fluids synergistically improved material performance.\u003c/p\u003e \u003cp\u003eCurrent research on Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e diluent-assisted direct nitridation of Si powder primarily focuses on optimizing powder synthesis processes [\u003cspan additionalcitationids=\"CR15 CR16 CR17 CR18 CR19\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. However, the mechanistic influence of this critical parameter on the mechanical properties and thermal conductivity of Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e ceramic substrates fabricated via an integrated aqueous tape casting-reaction sintering approach remains systematically unexplored. This study employs a novel water-based binder system to systematically investigate the effects of solid loading and additive dosage on slurry rheology, identifying the optimal formulation. Building on this optimized system, we further elucidate the influence of Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e diluent content on the mechanical properties and thermal conductivity of reaction-sintered Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e ceramic substrates.\u003c/p\u003e"},{"header":"2. Experimental procedure","content":"\u003cp\u003eThe starting materials used in this study were Si powder (\u0026gt;\u0026thinsp;99.99%, D\u003csub\u003e50\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;1.61 \u0026micro;m, Hebei Metallurgical Powder Research Institute, China), MgO (\u0026gt;\u0026thinsp;98.5%, D\u003csub\u003e50\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;4.51 \u0026micro;m, Aladdin Biochemical Technology Co., Ltd., China), Y\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (\u0026gt;\u0026thinsp;99.9%, D\u003csub\u003e50\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;6.40 \u0026micro;m, Sinopharm Chemical Reagent Beijing Co., Ltd., China), and α-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e (\u0026gt;\u0026thinsp;99.9%, D\u003csub\u003e50\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;2.57 \u0026micro;m, North Star Precision Technology Co., China). The binder system consisted of Duramax\u0026trade; B-1000 (Industrial use, Dow, USA), while ammonium citrate (grade 2, Aladdin Biochemical Technology Co., Ltd., China) and PEG-600 (grade 2, Aladdin Biochemical Technology Co., Ltd., China) served as the dispersant and plasticizer, respectively.\u003c/p\u003e \u003cp\u003eIn the tape casting process, the rheological behavior of the slurry directly determines the quality of green tape formation. Studies demonstrate that solid loading, dispersant addition, binder addition, and plasticizer/binder ratio (R-value) serve as critical parameters for regulating the slurry rheology. The experiment commenced by mixing ceramic powder with dispersant in deionized water, followed by 3.5 h ball milling to achieve a homogenously dispersed slurry system. Subsequent additions of binder and plasticizer were subjected to an additional 1.5 h ball milling to ensure compositional uniformity. After vacuum degassing (-0.01 MPa, 10 min), the slurry was cast under controlled conditions: doctor blade height of 0.3 mm and casting speed of 0.1 m/min. PET film was employed as the substrate material to facilitate tape release. A gradient drying protocol (30\u0026deg;C \u0026rarr; 50\u0026deg;C \u0026rarr; 70\u0026deg;C \u0026rarr; 50\u0026deg;C) effectively prevented cracking and warping caused by rapid solvent evaporation. The dried green tapes were precision-cut and laminated at 120\u0026deg;C under 3.0 T pressure for 10 min to ensure optimal interlayer bonding. Finally, the binder burnout and nitridation sintering processes yielded high-performance ceramic products.\u003c/p\u003e \u003cp\u003eDuring the heat treatment, the debinding step is carried out first by heating the sample from room temperature to 550\u0026deg;C at a ramp rate of 1\u0026deg;C/min, followed by a 2 h holding time to ensure complete decomposition and removal of organic additives, thereby preventing contamination in subsequent sintering. Subsequently, the nitridation reaction is performed under a nitrogen atmosphere, where the temperature is raised to 1350\u0026deg;C at 10\u0026deg;C/min and held for 3 h to achieve a high conversion rate of Si powder into the Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e phase. Finally, the temperature is further increased to 1900\u0026deg;C with a 2 h sintering step to ensure full densification of the ceramic substrate.\u003c/p\u003e \u003cp\u003eThe theoretical density of the material was calculated using the rule of mixtures, while the experimental density was determined by the Archimedes principle method. Flexural strength measurements were performed using three-point bending tests (ASTM D790) with rectangular specimens (3 mm \u0026times; 4 mm \u0026times; 36 mm). The tests were conducted at a span length of 30 mm and a crosshead speed of 0.5 mm/min using a WHY-300/10 universal testing machine (Shanghai Hualong Test Instruments Co., Ltd., China). Vickers hardness was measured in compliance with GB/T 16534\u0026thinsp;\u0026minus;\u0026thinsp;2009 standard using a 401MVD microhardness tester (Wolpert, USA) under an applied load of 49 N with a 15 s holding time. Fracture toughness was evaluated by analyzing the indentation-induced crack patterns following standard procedures.\u003c/p\u003e \u003cp\u003ePhase composition analysis was conducted using a Philips X\u0026rsquo;pert Pro X-ray diffractometer (XRD) with Cu-Kα radiation (λ\u0026thinsp;=\u0026thinsp;1.5406 \u0026Aring;) operated at 40 kV and 30 mA. The diffraction patterns were collected over a 2θ range of 10\u0026deg; to 80\u0026deg; with a step size of 0.013\u0026deg; and a scanning speed of 0.33\u0026deg;/s. Thermal diffusivity was measured following ASTM E1461-2013 standard using the laser flash method on an LFA 457 laser thermal analyzer (Netzsch, Germany). Disk-shaped specimens with a diameter of 12.7 mm and a thickness of 3 mm were prepared for the measurements. The thermal conductivity (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:k\\)\u003c/span\u003e\u003c/span\u003e) was calculated from the measured thermal diffusivity (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\alpha\\:\\)\u003c/span\u003e\u003c/span\u003e), bulk density (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\rho\\:\\)\u003c/span\u003e\u003c/span\u003e) and specific heat capacity (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{C}_{p}\\)\u003c/span\u003e\u003c/span\u003e) using the relationship \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:k=\\rho\\:{C}_{p}\\alpha\\:\\)\u003c/span\u003e\u003c/span\u003e. Microstructural characterization was performed using a field-emission scanning electron microscope (FE-SEM, Zeiss Sigma 300, Germany) to examine both the fracture surfaces and microstructure of the specimens.\u003c/p\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e3.1 Effects of solid loading and additives on tape-casting slurry and green body properties\u003c/h2\u003e\n \u003cp\u003eThe rheological behavior of ceramic slurries critically determines the quality of tape-cast silicon green sheets, particularly their thickness uniformity, surface roughness, and microstructural homogeneity. This study demonstrates that slurry rheology, controlled by the synergistic interactions among dispersant, binder, and plasticizer additives, is the primary factor governing the final ceramic performance.\u003c/p\u003e\n \u003cp\u003eAs shown in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(a), the Si slurry demonstrates pronounced shear-thinning behavior throughout the entire measurement range, making it particularly suitable for tape-casting applications At low shear rates, the high viscosity effectively suppresses particle agglomeration and sedimentation, ensuring colloidal stability. Conversely, the viscosity sharply decreases (\u0026eta;\u0026thinsp;\u0026lt;\u0026thinsp;10 Pa\u0026middot;s at shear rates\u0026thinsp;\u0026gt;\u0026thinsp;20 s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) under high-shear conditions, facilitating uniform slurry flow during the actual casting process. This pseudoplastic behavior enhances dispersion homogeneity and dimensional control in the formed tapes. Notably, the slurry viscosity exhibits an exponential increase with solid loading, indicating strong particle-particle interactions at elevated filler fractions.\u003c/p\u003e\n \u003cp\u003eAs shown in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(b), the slurry viscosity decreases progressively with increasing dispersant (ammonium citrate) concentration, demonstrating its effectiveness in enhancing fluidity. This rheological improvement stems from ammonium citrate\u0026rsquo;s ability to disrupt interparticle bonding forces, promoting homogeneous dispersion. Through pH-dependent ionization (e.g., NH\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e+\u003c/sup\u003e and citrate\u003csup\u003e3\u0026minus;\u003c/sup\u003e dissociation), the dispersant generates electrostatic repulsion between charged particle surfaces, effectively mitigating agglomeration and stabilizing the suspension system.\u003c/p\u003e\n \u003cp\u003eAs illustrated in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(c), the addition of Duramax\u0026trade; B-1000 induces a non-monotonic variation in slurry viscosity, characterized by an initial decrease followed by a slight increase and subsequent reduction. Importantly, the overall change in viscosity remains relatively small. This commercially available aqueous emulsion offers distinct advantages for tape-casting applications: (1) exceptionally low foam generation during processing, (2) remarkable insensitivity to ambient humidity variations, representing a critical improvement over conventional water-based binders, and (3) facilitation of high solid loading formulations due to its intrinsically low viscosity.\u003c/p\u003e\n \u003cp\u003eAs shown in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(d), the slurry viscosity exhibits a non-monotonic dependence on the plasticizer-to-binder ratio (R), initially increasing before decreasing. Unlike conventional long-chain polymers that depend on high molecular weight and extended linear segments for strong physical networks, Duramax\u0026trade; B-1000 exhibits resin-like polymer behavior. To achieve green bodies with high strength while maintaining flexibility, an optimal plasticizer addition is required. The plasticizer lubricates the binder chains, preventing excessive crosslinking and promoting chain coiling, thereby enhancing deformability. However, excessive plasticizer concentration can impair processability by increasing slurry viscosity due to disrupted polymer-solvent interactions.\u003c/p\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e(a) demonstrates that the slurry viscosity increases with rising solid content at a shear rate of 20 s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, showing a nonlinear rheological response. A dramatic viscosity enhancement occurs when the solid loading exceeds 50 wt%, indicating a critical transition in the suspension behavior. Previous studies [\u003cspan class=\"CitationRef\"\u003e21\u003c/span\u003e] have established that an optimal viscosity range of 0.2-1 Pa\u0026middot;s is essential for aqueous tape casting: slurries with viscosity below 0.2 Pa\u0026middot;s tend to form cracks during drying due to excessive fluidity, while those exceeding 1 Pa\u0026middot;s lose self-leveling capability, resulting in uneven tape surfaces. Based on this rheological analysis, solid loadings of 40 wt%, 45 wt%, and 50 wt% were systematically selected as experimental variables for subsequent orthogonal testing to investigate formulation-performance relationships.\u003c/p\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e(b) reveals a pronounced decrease in system viscosity as the dispersant concentration increases from 0.2 wt% to 1.4 wt%, with the most significant viscosity reduction occurring at 0.8 wt% dispersant addition. This observation demonstrates the crucial role of dispersant in optimizing the rheological properties of the slurry. While a maximum dispersant loading of 1.4 wt% achieves the lowest viscosity, the formulation of tape-casting slurries requires comprehensive consideration of various factors, particularly the influence of organic additives on green-body density and subsequent debinding behavior. Excessive dispersant content not only compromises the green density but may also induce defects during the debinding process. Based on these considerations, dispersant concentrations of 0.6 wt%, 0.8 wt%, and 1.0 wt% were carefully selected as experimental parameters for systematic investigation\u003c/p\u003e\n \u003cp\u003eThe rheological behavior exhibits distinct concentration-dependent characteristics at a shear rate of 20 s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ec). The slurry viscosity demonstrates remarkable stability within the 6.0\u0026ndash;10.0 wt% Duramax\u0026trade; B-1000 concentration range. A pronounced viscosity increase emerges when the binder content rises from 10.0 to 12.0 wt%, followed by a subsequent non-monotonic transition featuring an initial decrease and subsequent increase across the 12.0\u0026ndash;18.0 wt% range.\u003c/p\u003e\n \u003cp\u003eDuramax\u0026trade; B-1000, as an environmentally benign emulsion binder, simultaneously enhances mechanical strength and structural flexibility in ceramic systems. In tape casting applications, insufficient binder content (\u0026lt;\u0026thinsp;10.0 wt%) leads to inadequate green strength and defect formation, while excessive addition (\u0026gt;\u0026thinsp;14.0 wt%) induces debinding complications and reduces attainable solid loading. Consequently, the binder concentration should be minimized while meeting mechanical requirements.\u003c/p\u003e\n \u003cp\u003eBased on these considerations, the experimental matrix incorporates 10.0 wt%, 12.0 wt%, and 14.0 wt% Duramax\u0026trade; B-1000 concentrations, representing critical transition points in the rheological profile while balancing processing requirements and product performance.\u003c/p\u003e\n \u003cp\u003eThe rheological behavior at a shear rate of 20 s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ed) reveals a characteristic non-monotonic viscosity response to increasing R values. This trend suggests distinct structural transitions occurring within the slurry system as the PEG-600 content varies. At lower R values (R\u0026thinsp;\u0026lt;\u0026thinsp;0.7), the amphiphilic nature of PEG-600 enables effective particle dispersion and boundary lubrication, thereby reducing interparticle friction and decreasing the overall viscosity. As the R value increases to intermediate levels (0.7\u0026thinsp;\u0026lt;\u0026thinsp;R\u0026thinsp;\u0026lt;\u0026thinsp;1.1), competitive physical interactions between PEG-600 and the polymeric binder become predominant, potentially involving hydrogen bonding with hydroxyl groups, dipole-dipole interactions with polar moieties, and temporary physical entanglement of polymer chains. These interactions may generate transient network structures that increase the system\u0026apos;s resistance to shear flow. However, at higher R values (R\u0026thinsp;\u0026gt;\u0026thinsp;1.1), the additional PEG-600 molecules act primarily as plasticizers, disrupting the established polymer network through excessive dilution and weakening the intermolecular associations, ultimately leading to viscosity reduction.\u003c/p\u003e\n \u003cp\u003eThree representative R values (0.7, 0.9, and 1.1) were selected to systematically investigate these competing mechanisms. The 0.7 ratio represents the threshold where surface effects transition to bulk interactions, 0.9 corresponds to the potential maximum in network formation, while 1.1 indicates the onset of network destabilization.\u003c/p\u003e\n \u003cp\u003eThe factors and their levels (solid content, dispersant addition, binder addition, and R-value) chosen for the orthogonal experiments are summarized in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\n \u003cp\u003e\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eThe various quantities (wt.%) used for the orthogonal experiments\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003egroup\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003esolid content (A)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003edispersant addition (B)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ebinder addition (C)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eR value (D)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eThe orthogonal test design and experimental results are presented in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. In the orthogonal experiment, the effects of four factors on the maximum tensile strength, elongation at break, thickness reduction, and density were comprehensively analyzed. The optimal experimental conditions were determined as follows: solid content 45 wt%, ammonium citrate addition 0.4 wt%, Duramax\u0026trade; B-1000 binder addition 12.0 wt%, and R-value 0.7. This formulation effectively balances key performance indicators, including maximum tensile strength, elongation at break, thickness shrinkage, and density. Based on these findings, the subsequent preparation process of ceramic substrates was further optimized.\u003c/p\u003e\n \u003cp\u003e\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eThe orthogonal test protocol and experimental results\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSpecimen\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eUltimate tensile strength (MPa)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFracture elongation (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eThickness shrinkage (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eDensity (g/cm\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.2054\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e51.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.27\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.2380\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e37.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e55.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.29\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.0927\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e58.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.34\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.5474\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.40\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.3146\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e64.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.38\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.2814\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e46.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.31\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.2307\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e39.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.32\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.2821\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e34.76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.28\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.3308\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e38.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.29\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e3.2 Influence of seed addition amount\u003c/h2\u003e\n \u003cp\u003eBased on optimized processing parameters, high-purity fine Si powder and \u0026alpha;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e powder were used as starting materials with a Y\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e-MgO binary additive system. The sintering additives were proportioned according to the stoichiometric ratio (Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e: Y\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e: MgO\u0026thinsp;=\u0026thinsp;93 mol%: 2 mol%: 5 mol%) calculated for complete silicon nitridation. Six comparative experimental groups were designed as presented in Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e\n \u003cp\u003eTable 3 \u0026nbsp;Experimental formulations with varying additions of Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seeds\u003c/p\u003e\n \u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9.375%;\"\u003e\n \u003cp\u003eSpecimen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 25%;\"\u003e\n \u003cp\u003eNitrided Si\u003c/p\u003e\n \u003cp\u003e(mol%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003eY\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (mol%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003eMgO (mol%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e\u0026alpha;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e (mol%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9.375%;\"\u003e\n \u003cp\u003eS0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 25%;\"\u003e\n \u003cp\u003e93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21.875%;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9.375%;\"\u003e\n \u003cp\u003eS1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 25%;\"\u003e\n \u003cp\u003e91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21.875%;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9.375%;\"\u003e\n \u003cp\u003eS2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 25%;\"\u003e\n \u003cp\u003e89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21.875%;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9.375%;\"\u003e\n \u003cp\u003eS3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 25%;\"\u003e\n \u003cp\u003e87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21.875%;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9.375%;\"\u003e\n \u003cp\u003eS4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 25%;\"\u003e\n \u003cp\u003e85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21.875%;\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 9.375%;\"\u003e\n \u003cp\u003eS5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 25%;\"\u003e\n \u003cp\u003e83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21.875%;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 21.875%;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\u003c/table\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cdiv\u003e\n \u003cp\u003eFigure 3 shows the XRD patterns of samples with different Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed contents after re-sintering at 1900 ℃ for 2 h. All samples exhibit diffraction peaks of \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e and YMgSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003eN\u003csub\u003e2\u003c/sub\u003e, while S4 and S5 display weak Si\u003csub\u003e2\u003c/sub\u003eN\u003csub\u003e2\u003c/sub\u003eO peaks. After re-sintering, the \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e peak intensities increase, and all \u0026alpha;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e peaks disappear, confirming complete \u0026alpha;\u0026rarr;\u0026beta; phase transformation. No SiO\u003csub\u003e2\u003c/sub\u003e peaks are detected due to (1) the formation of amorphous grain-boundary glass phases and (2) partial SiO\u003csub\u003e2\u003c/sub\u003e volatilization at high temperatures. The reaction follows:\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv align=\"left\" class=\"colspec\"\u003e\u003cbr\u003e\u003c/div\u003e\u0026nbsp;\u003ctable id=\"Taba\" border=\"1\"\u003e\n \u003ccolgroup cols=\"2\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:3Si+2{N}_{2}\\to\\:{Si}_{3}{N}_{4}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e(4.1)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:Si{O}_{2}+2{N}_{2}+3Si\\to\\:2{Si}_{2}{N}_{2}O\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(4.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:Si{O}_{2}+{Si}_{3}{N}_{4}\\to\\:2{Si}_{2}{N}_{2}O\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(4.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:2MgO+Si{O}_{2}\\to\\:{Mg}_{2}Si{O}_{4}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(4.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{Mg}_{2}Si{O}_{4}+Si{O}_{2}\\to\\:2MgSi{O}_{3}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(4.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:3{Si}_{3}{N}_{4}+{Y}_{2}{O}_{3}+3MgSi{O}_{3}\\to\\:2YMg{Si}_{2}{O}_{5}{N}_{2}+3Si{O}_{2}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(4.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e clearly demonstrates the effect of Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed content on the growth of \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains. Samples S0 through S5 all display elongated rod-like \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains. As the Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed content increases from 0 wt% to 6 wt%, a gradual increase in the aspect ratio of \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains is observed. Sample S0 (0 wt% seeds) contains only short, stubby \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains with relatively large pores. With increasing seed content in samples S1 and S2, both the proportion of high-aspect-ratio \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains and the pore reduction become more pronounced. However, when seed content increases beyond 6 wt% up to 10 wt%, the aspect ratio of \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains begins to decrease progressively. Correspondingly, samples S3, S4 and S5 show increasing proportions of shorter \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains along with gradually enlarged pore structures.\u003c/p\u003e\n \u003cp\u003eWith increasing Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed content, the grain packing density first increases and then decreases. The seeds serve as heterogeneous nucleation sites during nitridation, significantly lowering the activation energy for Si powder nitridation and promoting the conversion of Si to Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e. This facilitates particle rearrangement and liquid-phase mass transport, which benefits densification and grain growth during resintering. However, excessive seed content causes particle agglomeration and uneven distribution, leading to non-uniform nitridation and pore formation. These defects subsequently impede densification and hinder uniform grain growth during resintering.\u003c/p\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e shows the density of resintered samples with varying Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed content. All samples exhibit relative densities exceeding 77%. When the seed content increases from 0 to 4 wt%, the density of Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e gradually rises, reaching a maximum relative density of 92.69% at 4 wt% seed addition. The seeds act as heterogeneous nucleation sites during the nitridation reaction, significantly reducing the activation energy for Si powder nitridation and promoting the conversion of Si into Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e. This facilitates particle rearrangement and liquid-phase mass transport during nitridation, benefiting subsequent densification and grain growth in the sintering stage.\u003c/p\u003e\n \u003cp\u003eHowever, when the seed content further increases to 4\u0026ndash;10 wt%, the density gradually decreases. Excessive Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed addition triggers elongated \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grain growth, leading to coarse, interlocked microstructures. This inhibits liquid-phase flow and traps residual pores, reducing densification. The primary driving force for densification stems from capillary forces during particle rearrangement in the liquid phase. Therefore, variations in additive content influence liquid-phase formation, significantly affecting the final densification of Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e materials.\u003c/p\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e shows the hardness of resintered samples with different Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed additions. The sample hardness first increases then decreases with increasing seed content, reaching a maximum value of 15.60 GPa at 4 wt% seed addition. When the seed content is below 4 wt%, the hardness increases progressively with higher seed content as the enhanced densification and refined microstructure strengthen the material. However, exceeding 4 wt% seed addition leads to decreased hardness. This deterioration results from reduced densification caused by impurities introduced from excessive seeds and the formation of overgrown \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e columnar grains. These elongated grains become interlocked, inhibiting liquid phase flow during sintering and increasing residual porosity, ultimately lowering the material hardness. The hardness evolution correlates directly with the density changes observed in Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e, demonstrating the critical balance in seed addition for optimal Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e ceramic performance.\u003c/p\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e shows the fracture toughness and flexural strength of resintered samples with varying Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed content. The fracture toughness first increases then decreases with increasing seed content, peaking at 6.6 MPa\u0026middot;m\u003csup\u003e1/2\u003c/sup\u003e for 4wt% seeds, which aligns with the concurrent maxima in density and hardness. At seed contents below 4wt%, increasing amounts introduce more \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains with high aspect ratios. These elongated grains create a self-toughening effect through crack deflection and bridging mechanisms that effectively hinder crack propagation. Examination of the fracture surfaces reveals these reinforcing grains progressively dominate the microstructure, improving toughness up to the optimal 4wt% level. Exceeding the 4wt% seed threshold triggers a series of microstructural degradations: \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains progressively lose their elongated morphology, accompanied by a declining population of high-aspect-ratio grains. Concurrently, enlarged pores and coarsened cracks emerge throughout the matrix, collectively undermining the material\u0026apos;s crack resistance capability. These microstructural degradations combine to significantly reduce the material\u0026apos;s resistance to crack propagation, leading to the observed decline in fracture toughness. The results demonstrate how the balance between grain morphology and defect formation dictates the mechanical performance of seeded Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e ceramics.\u003c/p\u003e\n \u003cp\u003eFlexural strength exhibited a positive correlation with sample density, showing a significant improvement with increasing density. Specimen S2 achieved the maximum flexural strength of 636.1 MPa, approaching the requirements for engineering applications. The enhanced densification contributed to reduced porosity, increased effective load-bearing area, and suppressed stress concentration, thereby strengthening the material. However, when the Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed content increased from 4 wt% to 10 wt%, porosity rose, leading to decreased densification and abnormal grain coarsening, which ultimately degraded flexural strength. In summary, an optimal Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed content (4 wt%) enhances both fracture toughness and flexural strength, whereas exceeding this threshold results in increased porosity and non-uniform grain growth, compromising mechanical performance.\u003c/p\u003e\n \u003cp\u003eAs shown in Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e, the thermal conductivity of Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e ceramics exhibited a maximum (60.74 W\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u0026middot;K\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in S2) with increasing seed content, attributable to microstructural modifications. Optimal seed addition promoted aligned \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains with high aspect ratios while suppressing porosity through improved particle packing during sintering. These microstructural refinements enhanced phonon transport by reducing pore-related scattering centers. Simultaneously, sintering additives effectively lowered oxygen impurity concentrations, further minimizing lattice defect scattering. The critical Y\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e/SiO\u003csub\u003e2\u003c/sub\u003e ratio governed oxygen solubility in the liquid sintering phase. Excessive seeding (\u0026gt;\u0026thinsp;4 wt%) introduced supplementary SiO\u003csub\u003e2\u003c/sub\u003e, destabilizing this ratio and compromising oxygen scavenging capacity. This mechanism accounts for the observed thermal conductivity reduction at higher seed contents (4\u0026ndash;10 wt%), where diminished Y\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e effectiveness permitted residual oxygen impurities to persist as phonon scattering sites[\u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e\n \u003cp\u003eThe mechanical and thermal properties of the resintered samples exhibited an initial increase followed by a subsequent decrease with increasing Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed content. Optimal performance was achieved at 4 wt% seed addition, where the relative density, Vickers hardness, fracture toughness, flexural strength, and thermal conductivity reached 92.69%, 15.6 GPa, 6.6 MPa\u0026middot;m\u003csup\u003e1/2\u003c/sup\u003e, 636.1 MPa, and 60.74 W\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u0026middot;K\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively. Microstructural analysis of the fracture surfaces revealed a predominant population of high-aspect-ratio \u0026beta;-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains under these optimized conditions.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eThis work employed a tape-casting combined with reaction-bonding sintering approach to fabricate Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e ceramic substrate materials at 1900\u0026deg;C, using cost-effective raw materials (high-purity Si powder) and an environmentally friendly Duramax\u0026trade; B-1000 binder system. Through orthogonal experiments, the optimal processing parameters for producing large-area, low-defect silicon green tapes were systematically investigated. The mechanical and thermal properties of the re-sintered ceramics prepared from these optimized green tapes were subsequently characterized. The main conclusions can be summarized as follows:\u003c/p\u003e \u003cp\u003e(1) This study employed non-toxic Duramax\u0026trade; B-1000 as the binder for preparing silicon green tapes via tape casting. Multiple parameters significantly influenced both the slurry rheology and the performance of dried tapes, including: solid content (45 wt%), Duramax\u0026trade; B-1000 addition (12.0 wt%), ammonium citrate dispersant addition (0.4 wt%), and the PEG-600 plasticizer to binder ratio (R\u0026thinsp;=\u0026thinsp;0.7). Through a designed L9(3\u003csup\u003e4\u003c/sup\u003e) orthogonal array of 9 experimental groups, the optimal processing window was identified. The resulting green tapes exhibited smooth defect-free surfaces, minimal shrinkage, and balanced mechanical strength with flexibility.\u003c/p\u003e \u003cp\u003e(2) During re-sintering, increasing Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seed content initially enhanced material performance before declining beyond an optimal point. Samples with 4 wt% seed additions achieved 92.69% relative density, 15.6 GPa Vickers hardness, 6.6 MPa\u0026middot;m\u003csup\u003e1/2\u003c/sup\u003e fracture toughness, 636.1 MPa flexural strength, and 60.74 W\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u0026middot;K\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e thermal conductivity. Microstructural analysis showed predominantly elongated β-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains with corresponding diffraction peaks in XRD patterns.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eCompeting Interests\u003c/h2\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n\u003ch2\u003eFunding\u003c/h2\u003e\n\u003cp\u003eThis work was supported by the National Natural Science Foundation of China (No. 51872265, No. 51902290), Collaborative Innovation Major Special Project of Zhengzhou (No. 20XTZX12025) and Program for Leading Talents of Science and Technology in the Central Plain of China 2022 (No. 234200510002). The authors would like to thank the above for their support.\u003c/p\u003e\n\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eYuan Liu: Experimental Design, Experimental Operation, Data Analysis and Organization, Literature Survey, Writing -original draftYuanfei Liu: Experimental operation, data arrangement and analysis, literature surveyJie Fu: Data organization and analysis, literature surveyChengliang Ma: Resources, Writing - review \u0026amp; editing, Supervision\u003c/p\u003e\n\u003ch2\u003eAcknowledgments\u003c/h2\u003e\n\u003cp\u003eThis work was supported by the National Natural Science Foundation of China (No. 51872265, No. 51902290), Collaborative Innovation Major Special Project of Zhengzhou (No. 20XTZX12025) and Program for Leading Talents of Science and Technology in the Central Plain of China 2022 (No. 234200510002). The authors would like to thank the above for their support.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eJr.C.R. Eddy, D.K. Gaskill, Silicon carbide as a platform for power electronics, Science. 324 (5933) (2009) 1398-1400, https://www.science.org/doi/10.1126/science.1168704.\u003c/li\u003e\n\u003cli\u003eY. Zhou, H. Hyuga, D. Kusano, Y.I Yoshizawa, T. Ohji, K. Hirao, Development of high-thermal-conductivity silicon nitride ceramics, J. Asian Ceram. Soc. 3 (3) (2015) 221-229, https://doi.org/10.1016/j.jascer.2015.03.003.\u003c/li\u003e\n\u003cli\u003eC. Buttay, D. Planson, B. Allard, D. Bergogne, P. Bevilacqua, C. Joubert, M. Lazar, C. Martin, H. Morel, D. Tournier, C. Raynaud, State of the art of high temperature power electronics, Mater. Sci. Eng. B 176 (4) (2011) 283-288, https://doi.org/10.1016/j.mseb.2010.10.003.\u003c/li\u003e\n\u003cli\u003eF. Hu, Z.P. Xie, J. Zhang, Z.L. Hu, D. An, Promising high-thermal-conductivity substrate material for high-power electronic device: silicon nitride ceramics, Rare Met. 39 (2020) 463-478, https://doi.org/10.1007/s12598-020-01376-7.\u003c/li\u003e\n\u003cli\u003eC.C. Ye, H.Q. Ru, C.P. Zhang, W. Wang, D.L. Chen, Fracture toughness of Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e ceramic composites: Effect of texture, J. Eur. Ceram. Soc. 41 (13) (2021) 6346-6355, https://doi.org/10.1016/j.jeurceramsoc.2021.06.008.\u003c/li\u003e\n\u003cli\u003eX. Zhu, Y. Zhou, K. Hirao, Z. Lenč\u0026eacute;\u0026scaron;, Processing and thermal conductivity of sintered reaction‐bonded silicon nitride. I: effect of Si powder characteristics, J. Am. Ceram. 89 (11) (2006) 3331-3339, https://doi.org/10.1111/j.1551-2916.2006.01195.x.\u003c/li\u003e\n\u003cli\u003eY. Zhou, H. Hyuga, D. Kusano, Y.I. Yoshizawa, K. Hirao, A tough silicon nitride ceramic with high thermal conductivity, Adv. Mater. 39 (23) (2011) 4563-4567, https://doi.org/10.1002/adma.201102462.\u003c/li\u003e\n\u003cli\u003eY.S. Li, H.N. Kim, H.B. Wu, M.J. Kim, J.W. Ko, J.M.Y. Kim, Y.J. Park, Z.R. Huang, H.D. Kim, Improved thermal conductivity of sintered reaction-bonded silicon nitride using a BN/graphite powder bed, J. Eur. Ceram. Soc. 37 (15) (2017) 4483-4490, https://doi.org/10.1016/j.jeurceramsoc.2017.05.045.\u003c/li\u003e\n\u003cli\u003eY. Zhou, H. Hyuga, D. Kusano, M. Chika, H. Kiyoshi, Effects of yttria and magnesia on densification and thermal conductivity of sintered reaction‐bonded silicon nitrides, J. Am. Ceram. 102 (4) (2019) 1579-1588, https://doi.org/10.1111/jace.16015.\u003c/li\u003e\n\u003cli\u003eT. Wakihara, M. Yabuki, J. Tatami, K. Komeya, T. Meguro, H. Kita, N. Kondo, K. Hirao, Effect of diluents on post-reaction sintering of silicon nitride ceramics, Key Eng. Mater. 352 (2007) 185-188, https://doi.org/10.4028/www.scientific.net/KEM.352.185.\u003c/li\u003e\n\u003cli\u003eJ.J. Yu, W.M. Guo, L.Y. Zeng, H.T. Lin, Effect of SiO\u003csub\u003e2\u003c/sub\u003e addition on Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e ceramics prepared by rapid nitridation and post-sintering route, Ceram. Int. 43 (16) (2017) 13901-13906, https://doi.org/10.1016/j.ceramint.2017.07.116.\u003c/li\u003e\n\u003cli\u003eX. Jin, P.F. Xing, Y.X. Zhuang, J. Kong, S.N. Jiang, D.H. Wei, Effect of Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e diluent on direct nitridation of silicon powder, Ceram. Int. 45 (8) (2019) 10943-10950, https://doi.org/10.1016/j.ceramint.2019.02.175.\u003c/li\u003e\n\u003cli\u003eH.M. Oh, H.K. Lee, Controlling the width of particle size distribution of Si powder and properties of sintered reaction-bonded silicon nitride (SRBSN) ceramics with high thermal conductivity, Ceram. Int. 46 (8) (2020) 12517-12524, https://doi.org/10.1016/j.ceramint.2020.02.014.\u003c/li\u003e\n\u003cli\u003eH. Hyuga, N. Kondo, H. Kita, Fabrication of dense \u0026beta;‐SiAlON ceramics with ZrO\u003csub\u003e2\u003c/sub\u003e additions via a rapid reaction‐bonding and postsintering route, J. Am. Ceram. 94 (4) (2011) 1014-1018, https://doi.org/10.1111/j.1551-2916.2010.04192.x.\u003c/li\u003e\n\u003cli\u003eH. Hyuga, Y. Zhou, D. Kusano, K. Hirao, H. Kita, Nitridation behaviors of silicon powder doped with various rare earth oxides, J. Ceram. Soc. Jpn. 119 (1387) (2011) 251-253, https://doi.org/10.2109/jcersj2.119.251.\u003c/li\u003e\n\u003cli\u003eB.R. Golla, J.W. Ko, J.M. Kim, H.D. Kim, Effect of particle size and oxygen content of Si on processing, microstructure and thermal conductivity of sintered reaction bonded Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e, J. Alloys Compd. 595 (2014) 60-66, https://doi.org/10.1016/j.jallcom.2014.01.131.\u003c/li\u003e\n\u003cli\u003eY. Zhou, T. Ohji, H. Hyuga, Y.C. Yoshizawa, N. Murayama, K. Hirao Fracture resistance behavior of high‐thermal‐conductivity silicon nitride ceramics, Int. J. Appl. Ceram. Technol. 11(5) (2014) 872-882, https://doi.org/10.1111/ijac.12109.\u003c/li\u003e\n\u003cli\u003eW.M. Guo, L.X. Wu, H. Xie, Y. You, H.T. Lin, Effect of TiO\u003csub\u003e2\u003c/sub\u003e additives on nitridation of Si powders, Mater. Lett. 177 (2016) 61-63, https://doi.org/10.1016/j.matlet.2016.04.129.\u003c/li\u003e\n\u003cli\u003eF.W. Chang, T.H. Liou, F.M. Tsai, The nitridation kinetics of silicon powder compacts, Thermochim. Acta 354 (1-2) (2000) 71-80, https://doi.org/10.1016/S0040-6031(00)00432-9.\u003c/li\u003e\n\u003cli\u003eM. M\u0026uuml;ller, W. Bauer, R. Knitter, Processing of micro-components made of sintered reaction-bonded silicon nitride (SRBSN). Part 1: Factors influencing the reaction-bonding process, Ceram. Int. 35 (7) (2009) 2577-2585, https://doi.org/10.1016/j.ceramint.2009.02.013.\u003c/li\u003e\n\u003cli\u003eJ. Wang, L. Gao, Surface and electrokinetic properties of Y-TZP suspensions stabilized by polyelectrolytes, Ceram. Int. 26 (2) (2000) 187-191, https://doi.org/10.1016/S0272-8842(99)00038-3.\u003c/li\u003e\n\u003cli\u003eX. Jin, P. Xing, Y. Zhuang, J. Kong, S.N. Jiang, D.H. Wei, Function mechanism of Y\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e additive in silicon powder nitridation, Int. J. Appl. Ceram. Technol. 16 (4) (2019) 1407-1415, https://doi.org/10.1111/ijac.13207.\u003c/li\u003e\n\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":"silicon","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scon","sideBox":"Learn more about [Silicon](https://www.springer.com/journal/12633)","snPcode":"12633","submissionUrl":"https://submission.nature.com/new-submission/12633/3","title":"Silicon","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"silicon nitride ceramic substrates, aqueous tape casting, seed, reaction-bonding sintering","lastPublishedDoi":"10.21203/rs.3.rs-6518304/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6518304/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study presents a cost-effective and environmentally friendly approach for fabricating large-area, low-defect Si₃N₄ ceramic substrate materials using tape casting combined with reaction-bonding sintering at 1900\u0026deg;C. High-purity Si powder and a non-toxic Duramax\u0026trade; B-1000 binder system were employed as raw materials. Orthogonal experiments (L9(3\u003csup\u003e4\u003c/sup\u003e) array) optimized key parameters: 45 wt% solid content, 12.0 wt% binder, 0.4 wt% ammonium citrate dispersant, and a PEG-600 plasticizer to binder ratio (R) of 0.7. These conditions produced defect-free green tapes with smooth surfaces, minimal shrinkage, and balanced strength-flexibility properties. During re-sintering, the addition of 4 wt% Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e seeds maximized performance, yielding ceramics with 92.69% relative density, 15.6 GPa Vickers hardness, 6.6 MPa\u0026middot;m\u003csup\u003e1/2\u003c/sup\u003e fracture toughness, 636.1 MPa flexural strength, and 60.74 W\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e\u0026middot;K\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e thermal conductivity. Microstructural analysis revealed elongated β-Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e grains, confirmed by XRD. This work demonstrates a scalable fabrication route for high-performance Si\u003csub\u003e3\u003c/sub\u003eN\u003csub\u003e4\u003c/sub\u003e substrates using economical and eco-conscious processing.\u003c/p\u003e","manuscriptTitle":"Eco-Friendly Fabrication of High-Performance Si3N4 Ceramic Substrates via Aqueous Tape Casting and Reaction-Bonding Sintering: Effects of α-Si3N4 Seeding","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-20 11:13:20","doi":"10.21203/rs.3.rs-6518304/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-06-13T05:39:55+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-27T04:57:59+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-24T04:56:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"152093549118380379635747151008436682298","date":"2025-05-18T12:23:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"166097786033563534529769288952425588232","date":"2025-05-18T03:36:27+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"127455577483031663802792023365417056334","date":"2025-05-18T03:26:44+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-05-16T03:24:35+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-13T08:10:47+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-13T08:05:39+00:00","index":"","fulltext":""},{"type":"submitted","content":"Silicon","date":"2025-04-24T07:27:49+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"silicon","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scon","sideBox":"Learn more about [Silicon](https://www.springer.com/journal/12633)","snPcode":"12633","submissionUrl":"https://submission.nature.com/new-submission/12633/3","title":"Silicon","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"d22033ea-9e53-4ef5-ae19-e0ee4236d5e4","owner":[],"postedDate":"May 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-07-26T12:23:31+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-20 11:13:20","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6518304","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6518304","identity":"rs-6518304","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}