Fundamental Research for Fabrication and Application of high hardness Materials with Nano Size Grain Boundary at high temperature

本研究对Si-B-C体系复合材料的制备及应用研究进行了研究，以确定是否可以改善含碳SiB6陶瓷的高温性能。在同时存在碳的情况下，对样品进行热压烧结，以研究对烧结复合材料性能的影响。结果表明，在1973 K、25 MPa的真空条件下，SiB6与C烧结体的相对密度达到了良好的致密化状态。含0、5、10、15和20质量% C烧结体的SiB6的孔隙率分别为1.0%、1.5%、2.8%和20%。XRD分析结果表明，烧结后的复合材料除了存在与SiB6相关的衍射峰外，还存在与B4C和SiC相关的衍射峰，但C和B4C和SiC的衍射峰均消失。含10质量% C的SiB6复合材料在室温和1073 K时的维氏硬度分别为28和22 GPa。复合材料的硬度不随测量温度的升高而降低。添加10质量% C的SiB6复合材料的高温维氏硬度高于Al2O3、ZrO2和Si3N4烧结体。

In this study, the fabrication and application research of Si-B-C system composite were investigated, to confirm whether the high temperature properties of SiB6 containing carbon ceramics can be improved. The samples were sintered by hot pressing in the simultaneous presence of carbon, in order to investigate the effects on properties of the sintered composites. It was found that the relative density of SiB6 with C sintered bodies became good densification at 1973 K for 1 hour in vacuum under a pressure of 25 MPa. The porosity of SiB6 containing 0, 5, 10, 15, and 20 mass% C sintered bodies was 1.0 %, 1.5 %, 2.8 %, and 20 %, respectively. Based on the XRD analysis results, the sintered composites exhibited diffraction peaks considered to be relevant to B4C and SiC, in addition to those relevant to SiB6, However, the diffraction peaks for C disappeared, and those for B4C and SiC. The Vickers hardness of the SiB6 with 10 mass % C composite was 28 and 22 GPa at room temperature and 1073 K, respectively. The hardness of the composite did not decrease with increasing measurement temperature. The Vickers hardness at high temperature of SiB6 addition of 10 mass% C composite was higher than Al2O3, ZrO2, and Si3N4 sintered bodies.