Y2O3함량과 소결조건에 따른 상압소결 AlN 세라믹스의 열전도도 고찰

Abstract

Aluminum nitride (AlN) has excellent thermal conductivity, whereas it has some disadvantage such as low sinterability. In this study, the effects of sintering additive content and sintering condition on thermal conductivity of pressureless sintered AlN ceramics were examined on the variables of 1~3 wt% sintering additive (Y 2 O 3 ) content at 1900℃ in N 2 atmosphere with holding time of 2~10 h. All AlN specimens showed higher thermal conductivity as the Y 2 O 3 content and holding time increase. The formation of secondary phases (yttrium aluminates) by reaction of Y 2 O 3 and Al 2 O 3 from AlN surface promoted the thermal conductivity of AlN specimens, because the secondary phases could reduce the oxygen contents in AlN lattice. Also, thermal conductivity was increased by long sintering time because of the uniform distribution and the elimination of the secondary phases at the grain boundary by the evaporation effect during long holding time. A carbothermal reduction reaction was also affected on the thermal conductivity. The thermal conductivity of AlN specimens sintered at 1900℃ for 10 h showed 130~200W/mK according to the content of sintering additive.