Effects of Additives of CaO and Rare-Earth Oxides on the Sintering Behavior of AIN Ceramics

摘要

The effect of additives of CaO plus three different rare-earth oxides (Y, Sm and Gd, separately)on the sintering behavior of AlN ceramics has been evaluated at 1700℃ by using a MoSiheater _2 and ambient atmosphere. The results of density measurements show that the atomic weight of the rare-earth element may substantially affect the apparent density of the sintered AlN specimen due to the kinetics of atomic diffusion during sintering. The optimum results of this study show that these additives are effective in obtaining an apparent density of 3.26 g/cm~3(aproaching a 10 % theoretical density of AlN). The Vicker's hardness of the sintered AlN can reach a high value of 1310 kg/mm~2a .3 nAd laon gaeprp saoreankti ndge ntismitey of b3e.3tw4 egecm 3~ and 5 h is necessary to practically eliminate the minor oxide phases.