Intergranular Microstructure of Yb_2O_3-added AlN Sintered by Millimeter-Wave Heating

摘要

Aluminum nitride was sintered by 28GHz millimeter-wave heating method, and the relation between thermal conductivity and microstructure in the sintered AlN was investigated. Aluminum nitride with high thermal conductivity over 200W/(m·K) was obtained by millimeter-wave-sintering at low temperature of 1700℃ for 2hrs under nitrogen/hydrogen mixed gas atmosphere. From the observation by HR-TEM, intergranular layer in AlN sintered by millimeter-wave heating was thinner than that sintered by conventional heating. The high thermal conductivity over 200W/(m·K) of the millimeter-wave sintered AlN is attributed to the formation of the thin intergranular layer in spite of a short sintering time and low sintering temperature, as compared with conventional sintering methods.