Study of rare-earth oxide sintering additive systems for Spark Plasma Sintering AlN ceramics

Dense aluminum nitride (AlN) ceramics were prepared by Spark Plasma Sintering with rare-earth oxide and CaF2 as multiple components sintering additives. The effect of sintering additives 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. The multiple components sintering additives not only promoted densification through liquid-phase sintering but also improved thermal conductivity by decreasing oxygen impurities. Thermal conductivity of samples sintered with 2 wt.% Sm2O3–1 wt.% CaF2 was higher than those of other samples. During the Spark Plasma Sintering process, the microstructures played a key role in controlling the thermal conductivity of AlN ceramics.