Effect of ZnO on structural and dielectric properties of AlN ceramics

Sintering AlN ceramics at lower temperatures and suppressing the formation of Al2O3 are challenges. This study is focused on addressing the above problems. Zinc oxide (ZnO)-added AlN ceramics have been prepared, and the effect of ZnO on structural, dielectric, and electrical properties is investigated systematically. AlN (pure and additive) ceramics are sintered using the powder bed method at 1700 & DEG;C in the presence of nitrogen flow. In addition, the small initial particle sizes and ZnO also help decrease the sintering temperature to 1700 celcius and densify AlN at lower temperatures due to the formation of the eutectic phase around 1400 & DEG;C. The XRD pattern of ZnO-added AlN ceramics revealed that the sintered ceramics are pure AlN phase, wurtzite structure with P63mc space group of space group number 186. The Raman spectrum of all sintered AlN-ZnO composites exhibited six vibrational modes of wurtzite AlN. The XPS results confirm Al 2p, Zn 2p, N 1s, and O1s presented in the AlN-15ZnO composite ceramic. This result proves oxygen in the AlN-15ZnO composite ceramics on the surface, not in grains. The powder bed prevents the formation of Al2O3 and enhances densification. The best additive AlN-15ZnO composite obtained dielectric permittivity of 5.5 to 7.4 in the variation of temperature from 30 to 500 & DEG;C. The impedance spectroscopy revealed that the AlN-ZnO composite ceramics contain non-Debye-type relaxations. The best microwave dielectric properties (& epsilon;r = 7.195 and tan & delta; = 4.90 x 10-3) is obtained for the best composite AlN-15ZnO ceramic for transmission of signals with high speed in electronic applications.