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

摘要

To fabricate porous Si_3N_4 ceramics with a complex shape easily, a simple and low-cost technique combining foaming and pres-sureless-sintering is explored. The foaming pressure has a decisive effect on the microstructure, pore size distribution, porosity and mechanical properties of the porous Si_3N_4 ceramics. As the foaming pressure increases, the porous Si_3N_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.