AlN-Mo复合陶瓷的介电性能研究

Research on Dielectric Properties of AlN-Mo Composite Ceramics

以AlN和Mo为原料,采用放电等离子体烧结技术(SPS)制备了AlN-Mo复合衰减材料。运用XRD、金相显微镜、介电频谱等测试手段对复合衰减陶瓷的相组成、显微组织、复介电常数和电阻率进行表征,研究了提高渗流阈值的方法和影响复合陶瓷介电性能的因素。结果表明,添加体积分数1%的Ni可以使复合陶瓷的渗流阈值达到23%(体积分数);复合陶瓷的介电常数、损耗随Mo含量的增加而增大,同一组分复合陶瓷的介电性能可通过改变导电相的分布状态实现可控调节,并从复合陶瓷的显微组织、电阻率及介电理论上对上述结果予以解释。

AlN-Mo composite ceramics are prepared by spark plasma sintering （SPS）. The phase composition, microstructure, dielectric properties and resistivity of the composite ceramics are tested by XRD, optical microscope and dielectric frequency spectrum. The method of increasing the percolation threshold and the influence factors to dielectric properties of the composite ceramics are explored. The results show that the percolation threshold （volume fraction） can be improved to 23 % by adding 1 % Ni （by volume） into the composite ceramics. The dielectric constant and loss of the composite ceramics are increased with increasing Mo content. Dielectric properties of the composite ceramics can be controlled by adjusting the distribution of Mo particles for the same composition. The above results are explained from the aspects of the microstructure of composite materials, electrical resistivity and dielectric theory.