Modulation of pore structure in SiC porous ceramics: Impact of SiC powder particle size and distribution span

According to particle packing theory, SiC porous ceramics with tailored porosity and pore dimensions can be fabricated by modifying the particle size and distribution range of SiC powder via the pressureless sintering method. The density of the green body formed under uniaxial pressure markedly diminishes with a reduction in particle packing density, while the apparent porosity of the SiC porous ceramics produced through high- temperature sintering significantly increases, resulting in a substantial enhancement of pure water flux. The increased span of SiC particle size distribution allows fine particles to efficiently occupy the interstices between larger particles, enhancing the densification of both the green and sintered bodies. Concurrently, the fine particles refine the pore size by filling larger voids; however, this results in a reduction of pure water flux. A reduction in particle size can lead to a drop in pore size of SiC porous ceramics when the particle size distribution range is comparable.