Effect of foaming pressure on the properties of porous Si3N4 ceramic fabricated by a technique combining foaming and pressureless sintering

Abstract

To fabricate porous Si 3 N 4 ceramics with a complex shape easily, a simple and low-cost technique combining foaming and pressureless-sintering is explored. The foaming pressure has a decisive effect on the microstructure, pore size distribution , porosity and mechanical properties of the porous Si 3 N 4 ceramics. As the foaming pressure increases, the porous Si 3 N 4 ceramics become uniform in microstructure, change gradually in pore size distribution from bimodal to unimodal, slowly reduce in porosity and pore size, and improve significantly in mechanical properties.