Achieving high-strength, hierarchically porous SiC ceramics with micron-scale periodic architecture via vat photopolymerization

Porous silicon carbide (SiC) ceramics are extensively utilised in a wide array of industrial applications. However, achieving a high porosity in SiC ceramic while balancing high strength remains a significant challenge. Here, high strength, hierarchically porous SiC ceramics with micron-scale periodic architectures are fabricated through a combination of vat photopolymerization additive manufacturing and pressureless sintering. The SiC powder is subjected to oxidation to enhance the curing depth of the SiC photosensitive slurry. Two strategies, including the reduction of the spacing between particles and the increase of SiC powder sintering activity, are employed to improve the strength of micro porous SiC ceramics without significantly decreasing its porosity. Sintering activity doses are realised at the SiC particle interfaces, which facilitates grain migration and diffusion and, eventually, generates both a high flexural strength of 122.38 ± 3.87 MPa and a high porosity of 41.57 ± 0.41%. Hierarchically porous SiC ceramic structures with micron-scale periodic architectures and a wall thickness of 50μm, a high open porosity surpassing 83% and a compression strength of 5.62 ± 0.31 MPa were also yielded. This work achieves the desired balance between mechanical strength and porosity and offers a novel pathway for the production of high-performance porous ceramics.