Dielectric properties of AlN/Mo composite ceramics prepared by spark plasma sintering method at different processing conditions

Abstract

In this study, the effects of powder mixed method, sintering temperature, and the additive amount of the conductive phase on the dielectric loss tangent and permittivity constant of AlN/Mo composite ceramics were investigated. All the ceramic samples were prepared by spark plasma sintering (SPS). AlN composite ceramics with additional 10 vol% Mo sintered at 1400 °C holding for 5 min exhibit the best dielectric loss tangent, which is greater than 0.23. AlN/Mo ceramics with additional 20 vol% Mo become conductive, with the resistivity of 0.05–0.06 Ω·m. High-energy ball milling is better than magnetic stirring powder mixing method. In addition, the additive Mo and lower sintering temperature lead to a better property with the increase in the electromagnetic wave frequency range of 1 × 103–1 × 106 Hz.