Influence of Phase Change in Interaranular Oxides to Thermal Conductivity of AIN Sintered by Millimeter-Wave Heating

Abstract

The relationship between thermal conductivity and intergranular oxide phase variation in AlN sintered by millimeter-wave heating was investigated. The thermal conductivity was increased with the decrease of a ratio of Al₂O₃ to Yb₂0₃+Al₂O₃ in the intergranular phase. When a high thermal conductivity of 210 W/(m⋅K) was obtained at 1973 K for 3 hrs under a mixed gas atmosphere of N₂ with 3 vol% H₂, Yb₂O₃ phase was observed as an intergranular phase, unlike conventional sintering.