Permeating behaviour of porous SiC ceramics fabricated with different SiC particle sizes

Abstract

Permeating behaviour is one of the most important factors of porous ceramics used for gas/liquid filters or membrane/catalysis supporters. Insufficient research has reported on the effect of raw particle size on permeating behaviour and the relationship between particle size and pore size of fabricated porous ceramics. In this work, porous SiC ceramics were fabricated with raw SiC particles of different grit designations and the effect of particle size on the permeating behaviour and equivalent pore size of the resulting porous ceramics were investigated. Due to oxidation of the SiC particles during the firing process, resulting materials with finer raw particles exhibited higher mass gain and lower bulk and true density. When the grit designation changed from 2000# to 120#, the strength of the resulting materials declined, and the Darcy permeability k1 increased from 6.65 × 10−15 to 4.85 × 10−13 m2. The ratio of the hydraulic equivalent diameter of pores to raw particle size in the resulting materials decreased from 0.25 to 0.11, indicating that the hydraulic equivalent pore size did not increase proportionally with the particle size increase. Further measures should be employed to enlarge pore size in porous ceramics to enhance its permeability.