Effect of MgO and Sintering Temperatures on Microstructures and Properties of Al_2O_3 Transparent Ceramic

Al2O3 transparent ceramics were sintered by using high purity Al2O3 powder in H2 atmosphere.The effect of additives and sintering temperatures on densification process,microstructures and properties were investigated.Controlled grain growth,increased density and improved sintering performance are related to appropriate doping MgO.The optimum MgO content is 0.05wt%.With increasing sintering temperature,grains fully develops and light transmittance increases.The optimum sintering temperature is 1850℃.The transparent alumina under the optimum conditions has the average grain size of 20μm at relative density of 99.62%,the total transmission of 93%,the Vic-kers hardness of 20.75GPa and the three-point bending strength of 320MPa.