Microstructure-permeability relation of porous beta-Si3N4 ceramics

Porous beta-Si3N4 ceramics with two distinct structures were produced by using two different Si3N4 sources to investigate the relationship between microstructure and permeability. Results showed that regardless of pore amount, size of pore channels, shape-distribution of beta-Si3N4 grains are more effective on permeability of porous Si3N4 ceramics. Higher permeability and lower contribution of inertial forces was obtained by microstructure consists of coarse and equiaxed grains even at lower porosity amount. Calculated Forchheimer number (Fo) and measured the local breadth of a pore also supported the effect of microstructure on permeability.