Abstract
Porous Si3N4 ceramics were fabricated by normal sintering of low-purity Si3N4 powder and 5mass%Y2O3 as sintering additive. Porous Si3N4 ceramics with >40% porosity were obtained at sintering temperatures in the range 1700-1800°C. The microstructural development, pore morphology, and mechanical properties of these porous ceramics were investigated. The strength of the porous Si3N4 ceramics was high for samples sintered at 1800°C. The high flexural strength was contributed by fine elongated β-Si3N4 grains and some large elongated grain. This paper outlines the use of low purity powder for the economical fabrication of porous Si3N4 ceramics.
