Effect of zirconia addition on dielectric loss and microstructure of aluminum nitride ceramics

The effects of sintering additives on dielectric loss tangent of AlN ceramics have been investigated. Different amounts of Y 2O 3 and ZrO 2 were added as sintering additives to AlN powder and pressureless sintering was performed at 1900 °C for 2 h in a flowing nitrogen atmosphere. ZrN phase was detected in AlN ceramics when ZrO 2 addition was more than 0.1 mol.%. Densification behavior of both Y 2O 3 and ZrO 2 doped AlN ceramics was found to be a little complicated, however addition of ZrO 2 was effective in the densification of the AlN ceramics. tan δ is found to increase from less than 1 × 10 −3 to around 6 × 10 −3 when ZrO 2 content was more than 0.1 mol.%.