SiC陶瓷表层改性的研究

Investigation on the properties of modified SiC surface

由于SiC陶瓷脆性大、冲击韧性低、加工性能差等特点在很大程度上限制了其应用范围,采用Al基合金熔渗SiC陶瓷的方法对SiC陶瓷表层进行改性处理.通过金相显微镜、SEM、EDS、XRD等检测方法对改性后的SiC陶瓷进行微观组织分析,通过万能试验机进行三点弯曲强度测定.结果表明改性后的SiC陶瓷表面生成一层含有Ti3SiC2三元相的反应层,反应层厚度随熔渗温度、时间呈先增加后减小的规律性变化,最厚可达500微米;反应层显微硬度约为500 HV,明显低于SiC陶瓷的硬度;改性后SiC陶瓷三点弯曲强度比SiC陶瓷提高了1.4倍.

The application of SiC ceramic is limited due to its large brittleness, low impact toughness and bad process ability. In the paper, the surface of SiC ceramic was modified by infiltrated in Al-based alloy liquid at various temperature and various time. The microstrueture was investigated by metallographic microscope, scanning electron microscope （SEM）, energy dispersive spectrometer （EDS）, and X-ray diffraction （XRD）. The mechanical properties was analyzed by universal testing machine. The results show that the reaction layer mainly consists of the ternary phase Ti3SiC2. The thickness of reaction layer is increased continuously until to a ＂peak value＂, and then let up with the change of temperature and time. The biggest thickness is 500 μm. The microhardness of reaction layer was about 500 HV, less than pure SiC obviously. Compared with pure SiC, the three-point bending strength of the modified SiC ceramics increased 1.4 times.