Effects of rare earth oxide additives on dielectric behaviors of aluminum nitride ceramics

The effects of Nd₂O₃ and Er₂O₃ addition on the sintering behaviors, dielectric properties and microstructure of AlN ceramics were investigated. The results show that the sintering temperature of AlN ceramics can be decreased; its relative density and dielectric behavior can be improved by adding rare earth oxide. The relative density of AlN ceramic with 3% (in mass) Er₂O₃ additive is 98.8%, its tan δ is only 1.3 × 10^-4, which is 5% of that of pure AlN ceramic. The microstructure analysis of AlN ce-ramic shows it has a nearly theoretical AlN lattice, and the secondary phases between AlN grains are less, indicating an improved dielectric property.