Microstructure-permeability relation of porous β-Si₃N₄ ceramics

Porous β-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 β-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 (F_o) and measured the local breadth of a pore also supported the effect of microstructure on permeability.