Effect of different nucleation temperatures on the microstructural development of alpha-SiAlON ceramics

Abstract

alpha-SiAlON ceramics with elongated grains were previously observed in different studies. Sintering conditions are known to have a significant role on the microstructural development. By the nucleation treatment application during sintering, alpha-SiAlON with needle-like microstructure can be achieved also in a nitrogen rich composition and utilizing commercial alpha-Si3N4, whereas typical equiaxed grains are formed if the nucleation was not applied prior to growth in the same system. In this study, Ca-Ce containing multication systems for two different compositions are chosen to combine the facility of Cc for elongated grain formation with the convenient separation of maximum rates for nucleation and grain growth of Ca. The effects of different nucleation temperatures are examined to understand the microstructural development behaviour of a-SiAlON grains in this system.