Influence of CaO-Y2O3 as Sintering Aid on the Microstructure and Properties of AlN Ceramics

The property and microstructure of hot-pressure and normal-pressure sintered AlN ceramics doped with CaO-Y2O3 were studied in this paper. The results obtained show that the second phase in the hot-pressure sintered AlN is Y3Al5O12 and that in the normal-pressure sintered AlN is Y3Al5O12 and Ca3Y2O6. The volume fraction of the second phase and the oxygen content dissolved in the AlN lattice of hot-pressure sintered AlN ceramics are lower than that of normal-pressure sintered AlN. The hot-pressure sintered AlN ceramic has good microstructure and high thermal conductivity of 200W/m·K.