Multi-strategy optimization for vat photopolymerization of SiC ceramic: Slurry design, printing precision, and defect-free debinding

Vat photopolymerization (VPP) enables the fabrication of complex silicon carbide (SiC) ceramic geometries but is often constrained by high slurry viscosity, limited cure depth, and debinding cracking. To address these challenges, a ternary particle packing system (50, 20, and 4 μm) was optimized via D-optimal design and dual surface modification. This strategy yielded a stable slurry with high solid loading (55 vol%) and low viscosity (5.94 Pa s), and significantly enhanced cure depth (124 μm). Furthermore, the incorporation of non-reactive PPG 200 mitigated photocuring shrinkage, controlling linear shrinkage between 0.15 % and 0.78 %. Crucially, Mercury Intrusion Porosimetry (MIP) confirmed that the preferential decomposition of PPG 200 creates an in-situ interconnected pore network. This mechanism effectively relieves internal pressure, enabling defect-free debinding. The final ceramics, sintered via reactive melt infiltration (RMI), exhibited a dense microstructure (0.72 % open porosity) and an average flexural strength of 289 ± 13.4 MPa. This work validates an integrated route for manufacturing high-performance, complex SiC components.