Preparation of Si3N4 Foam Ceramics with Nest-Like Cell Structure by Particle-Stabilized Foams

Silicon nitride, Si3N4 foam ceramics were prepared by particle-stabilized foams, and the stabilization of Si3N4 foams and the performance of Si3N4 foam ceramics were investigated. The Si3N4 particle-stabilized foams had high stabilization, the dried green bodies had little shrinkage, and the structure of dried green body surface had no macro-pores and cracks. The Si3N4 foam ceramics with nest-like cell structure were obtained, nest pores were jointed by elongated rod-shaped beta-Si3N4 grains with aspect ratio of 30 or so, pore distribution was uniform, the average pore size was about 16 mu m, and the flexural strength was in the range of 3.8 to 77.2 MPa when porosity varied from 82.1% to 60.6%.