Thermodynamical consideration indicates that Li2O, Y2O3 and CaOare effective sintering aids for AIN sintering. Commerciallyavailable AIN powders were pressureless-sintered with concurrentadditions of YZO3-CaO, Li2O-Y2O3-CaO and LiYO2 (Y2O3 . Li2O)-CaO.Doping with Li2O and LiYO2 caused densification of AIN ceramics at aprocessing temperature of 1600 deg C. This is due to reduction ofliquidus temperature in the Y2O3-CaO-A12O3-AIN system and toimprovement of wettability between liquid and AIN. Among thespecimens tested, AIN specimens with LiYO2 and CaO addition obtainedat 1600 deg C for 6 h indicated a high thermal conductivity of 172Wm-1K-1 and a high strength of 45O MPa.
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