Abstract
Sintering of the Sialon ceramics accompanied with decomposition of surface layer (i.s. SiO2) and Sialon itself. These decompositions are impossible to completely be restrain the decomposition, and give influence to the chemical composition, microstructure and crystal phase of the Sialon. The decompositions are influenced by sintering condition, especially temperature and pressure of nitrogen. In this paper, the influence of the decompositions to mechanical property (strength and toughness) of Sialon was studied. The oxygen content of raw material and sintering condition (nitrogen pressure) were changed to examine influence of decomposition. The results obtained were as follows, when oxygen content of raw material was small amount and the nitrogen pressure in temperature rising was low, the mechanical property of Sialon was high. This indicates that the decompositions of surface oxide layer of Sialon particle improves mechanical property of Sialon. The possibility of controlling decomposition of Sialon by sintering condition was found.
