热压烧结AlN-BN复合陶瓷的制备及介电性能

Hot-pressed AlN-BN Ceramic Composites and Its Dielectric Properties

用热压工艺制备一系列BN含量(质量分数)为0～30%的AlN-BN复合陶瓷材料,研究了三氧化二钇和碳酸钙添加剂对致密性及介电性能的影响.结果表明:三氧化二钇和碳酸钙均有促进瓷体致密化的作用,但碳酸钙含量增加会造成组分不均匀,介质损耗增加.BN的质量分数为20%、三氧化二钇质量分数为5%的条件下,获得相对介电常数为8.5、介质损耗为0.000 683(1 MHz下)的AlN-BN复合陶瓷材料.测定了复合陶瓷介电常数及介质损耗随频率 (0.01～1 MHz)变化的特性,探讨了复合陶瓷介电常数与介质损耗与制备工艺的关系.

A series of samples of hexagonal boron nitride-aluminum nitride (0~100, 5~95, 10~90, 15~85, 22~82, 70~30wt%) ceramic composites were prepared by hot-pressing in nitrogen gas at 1850℃ for 2 h, with reagent grade Y2O3 and CaCO3 as sintering aid. The dielectric characteristic and density of samples were investigated. The results show that dielectric loss is caused by the carbon in the samples. The larger its amount is, the more the dielectric loss is. The carbon in the samples is mainly from the hot-pressed mould. After improving the process, er reaches 8.5 and tand reaches 6.83×10-4.