High Frequency Dielectric Properties and Thermal Conductivity of AlN-BN Composites by Spark Plasma Sintering

Abstract

AlN-BN composite is considered to be a promising material for microwave transparent applications. In this paper, a series of AlN-BN composites with various content of BN (0 wt%, 5 wt%, 15 wt% and 30 wt%) were prepared by spark plasma sintering with multiple components sintering additives at a low temperature (1650 °C), and the effect of sintering conditions and composition on the thermal conductivity and high frequency dielectric properties within frequency range from 10 MHz to 1.5 GHz was investigated. The results show that the spark plasma sintering process and the multiple components of the sintering additives promote the densification of the samples. The thermal conductivity and dielectric constant of samples decrease with increasing BN content, while the variation of the dielectric loss depends on the content of residual carbon and other impurities which may result in the relaxation loss of electronic polarization and conductive loss.

Preparation and Electromagnetic Properties of Al₂O₃/Ni Composites

“…3(a), the dielectric constant of the composites remains approximately constant up to hundreds of MHz and then decreases sharply. The polarization mechanism within the frequency range from 1 MHz to hundreds of MHz is usually considered to be predominately the relaxation of electronic polarization [8]. We can observe from Fig.…”

Hardness and Electromagnetic Properties of YSZ/NiZn Ferrite Composites

“…Among the magnetic materials, NiZn ferrite is a soft magnetic material with good magnetic properties [1]. Recently, some researches have demonstrated that adding a certain amount of the magnetic particle to the structural ceramic matrix results in better mechanical and magnetic properties [2][3][4][5][6].…”