Sintering and composition of a powder mixture of fine Al2O3 and beta-sialon composite made from bauxite

The sintering and composition of samples made of powder mixtures consisting of fine a-AI2O3 powder and beta-Sialon composite powder which was made from bauxite by carbonthermal reduction and nitridation were studied. The proportion of fine a-AI2O3 to beta'-Sialon composite powder in the powder mixture and soaking time give influences on porosity and relative density of the samples sintered at 1600eC. AI2O3, 15R and MgO which was added in 2 wt.% to improve sintering of the sample disappeared in the samples made of single P'-Sialon composite powder. They solubilize into beta-Sialon. In the sample made of a powder mixture consiting of 60 wt.% beta'-Sialon composite to 40 wt.% a-AI2O3 with addition of 2 wt.% MgO, beta'-Sialon, ct-AI2O3 and MgAION coexist after sintering at 1600BC.