Microstructural Development of Sintered β-Si_3N_4 Powder

Dense silicon nitride ceramics were obtained from β-Si_3N_4 powder, the material wascomposed of small rodlike grains and equiaxed grains, the small rodlike grains dispersed uniformlyin the matrix. Sintering process consisted of three stages: rearrangement, grain shape regulate,grain growth. The microstructure was sensitive to the time at the beginning of sintering, andshowed stable when holding time was longer than 2h. High temperature increased the aspect ratioof rodlike grains. More additives increased the diameter of both equiaxed and rodlike grains.