Formation Behavior and Microstructure of Ca-α-Sialon

Ca-α-Sialons for the compositions MxSi3-xAlxOxN16--x with x ranging from 0.3 to 2.0 wereprepared by hot-pressing technique. The reaction sequence, formation behavior, variation of latticeparameters with the compositions and microstructure of Ca--Sialon were reported in this paper.The result showed that the crystalline phase of Ca- -Sialon in the sintered material consists of --Sialon and AIN-polytypoid 21R when x is equal to or greater than 1.0 and the 21R contentincreases as the x-value increases. TEM observation confirmed the phase assemblages of Ca- Sialon samples and further revealed the existence of elongated 'grain in the materials.