Study on Al_2O_3 Ceramics Prepared by Non-isothermal Sintering

Pure Al2O3ceramics(AL) and MgO-Y2O3 binary additives doped Al2O3ceramics(ALMY)were prepared by non-isothermal sintering,using high purity α-Al2O3 powder as the starting materials.The relative density,microstructure and Vickers hardness of the AL and ALMY samples at different sintering temperature were studied. The results show that the sintering temperature range of dense pure Al2O3 ceramics is narrow during non-isothermal sintering. The relative density and Vickers hardness of sample AL sintered at 1500 ℃ is 98. 1% and 18. 1 GPa,respectively. Due to the obvious grain coarsening and the formation of intragranular pores,the relative density and Vickers hardness of sample AL sintered at 1600 ℃ sharply decrease to 94. 6% and 12. 5 GPa,respectively. The introduction of MgOY2O3 binary additives broadens the densification temperature range and refined the grains for Al2O3 ceramics. Vickers hardness of sample ALMY sintered at 1500 ℃ and 1600 ℃ with relative density of over 98% are 19. 2 GPa and 17. 6 GPa,respectively.