Effect of Sm₂O₃ content on microstructure and thermal conductivity of Spark Plasma Sintered AlN ceramics

Dense aluminum nitride ceramics were prepared by Spark Plasma Sintering at a lower sintering temperature of 1700 °C with Sm₂O₃ as sintering additives. The effect of Sm₂O₃ content on the density, phase composition, microstructure and thermal conductivity of AlN ceramics was investigated. The results showed that Spark Plasma Sintering could fabricate dense AlN ceramics with superior thermal properties in a very short time. Sm₂O₃ not only facilitated the densification via the liquid-phase sintering mechanism but also improved thermal conductivity by decreasing oxygen impurity. Thermal conductivity decreased with increasing amount of Sm₂O₃ and the highest thermal conductivity was obtained for the AlN ceramics with 2 wt.% Sm₂O₃ content. During Spark Plasma Sintering process, only 2-3 wt.% sintering additives was enough to fabricate dense AlN ceramics, and the microstructures played a key role in controlling the thermal conductivity of AlN ceramics.