Formation and densification of α'-sialon ceramics

The reaction sequences! densification process and grain growth ln Y-a'-sialon ceramics have been followed. Experimental results indicate that the formation of a'-sialon, requiring a liquid phase, is a reaction controlled process, while the densification behaviour varies greatly with the amount and composition of the liquid phase as well as the appearance of some intermediate compounds. However, the completion of the formation of a' -sialon and the final densification under atmospheric nitrogen pressure is very difficult due to a minor amount and the high viscosity of the liquid phase left. Thus the typical a'-sialon ceramic microstructure contains a small fraction of a glassy grain boundary phase.