采用反应热压烧结工艺制备了BN—ZrB2-ZrO2复合材料。ZrB2由ZrO2、B4C、C反应生成,反应方程式为2ZrO2+B4C+3C=2ZrB2+4CO↑。通过改变原始ZrO2的含量,可以得到ZrB2与ZrO2比例不同的55%BN—ZrB2-ZrO2复合材料。在1600℃,90min,30MPa的烧结条件下,复合材料的致密度均达到93%以上。复合材料的抗弯强度、断裂韧性随ZrB2与ZrO2比例的降低先升高后降低。当复合材料中ZrB2与ZrO2比例的为2.5:1时,复合材料的维氏硬度、抗弯强度、弹性模量、断裂韧性分别为1.74GPa、291MPa、118GPa、4.2MPa.m^1/2。
(ZrB2-ZrO2)/BN composites were prepared by reactive hot-pressing at 1600 ℃ under 30 MPa for 90 rain using BN, ZrO2, B4C and C as original materials. ZrB2 were successfully obtained by following reaction 2ZrO2+B4C+3C=2ZrB2+CO↑. After adjusting the ratio of ZrB2 and ZrO2, the 55%BN-ZrB2-ZrO2 composite sintered at 1600 ℃, 30 MPa of pressure for 90 min is possessed of more than 93% relative density. With decreasing ZrB2/ZrO2 ratio, the mechanical properties of 55vol%BN-ZrB2-ZrO2 composites increase first and then decrease, reaching a maximum value at ZrB2: ZRO2=2.5:1. The vieker's hardness, elastic modulus, flexural strength and fracture toughness of BN-25%ZrB2-10%ZrO2 composite are 1.74 GPa, 291 MPa, 118 GPa, 4.2 MPa·m^1/2, respectively.