Fabrication of high-strength Si/SiC composites with low shrinkage rates via vat photopolymerization technology and liquid silicon infiltration

Vat photopolymerization (VPP) technology has shown great application potential in the manufacture of high-precision complex silicon carbide (SiC) based ceramic components. However, in comparison with the conventional fabrication technologies, the SiC ceramics produced by VPP technology have insufficient strengths or relatively larger shrinkage rates to meet the requirements of practical applications. Herein, we develop a novel bimodal SiC material recipe for VPP technology and prepare Si/SiC composites by the consequent liquid silicon infiltration (LSI) method. The addition of fine SiC particles improves the material’s mechanical properties significantly. The final products possess low shrinkage rates (3.52 ± 0.26% in the x-direction, 3.73 ± 0.39% in the y-direction, and 4.69 ± 0.35% in the z-direction) as well as high flexural strength (363.23 ± 14.21 MPa) and low open porosity of 0.097%. The material compositions and fabrication strategies proposed in this work demonstrate an efficient way for the additive manufacturing of high-precision complex Si/SiC ceramic parts (e.g. lightweight space mirrors and structural ceramic parts).