Phase Relations between α′- and β′-Sialons in Si3N4(-SiO2)-AlN-Y2O3 System

This paper discusses phase relations between α′- and β′-Sialons in the Si3N4(-SiO2)-AlN-Y2O3 system. The total amount of AlN and Y2O3 was varied from 5 to 11wt%, and the molar ratio of AlN/Y2O3 was 0 to 11. Specimens were prepared by hot-pressing. In specimens with a small amount of AlN, compounds including SiO2, that was contained in the Si3N4 powder, were detected. The solubility of α′-Sialon increased remarkably with increasing amount of additives and increasing molar ratio of AlN/Y2O3. On the other hand, those of β′-Sialon increased slightly.