Preparation of mullite-whisker-modified SiC porous ceramic with high filtration precision

The mullite-whisker-modified SiC porous ceramics were prepared by the oxide bonding method, using two additives (MoO 3 as a mineralizer and AlF 3 as a crystallization catalyst) to promote the growth of mullite whiskers. The microstructure and comprehensive properties of the sintered bodies were adjusted by controlling the sintering temperature and the additive content. The mullite whiskers obtained by controlling the sintering temperature and additives exhibit excellent microstructural characteristics (diameter: 0.1–0.5 μm, length: 3–6 μm, length-to-diameter ratio: 15–25). These formed mullite whiskers effectively intercepted particulate matter, and their interlocking structure provided higher strength to the sintered body. The resultant mullite-whisker-modified SiC porous ceramics demonstrated remarkable mechanical strength (43.8 ± 0.1 MPa) while maintaining high porosity (41.27 %) and excellent gas permeability (1.96 × 10 −14  m 2 ). After undergoing five thermal shock cycles at 850 °C, the material retained 92.69 % of its original strength and exhibited superior filtration efficiency of 99.6 % for PM2.5 particles.