论文部分内容阅读
以RSiC为基体,通过酚醛树脂浸渍裂解(PF-PIP)和MoSi2-Si-Cr合金活化熔渗(AMMI)复合工艺制备具有三维互穿网络结构的MoSi2(Cr5Si3)-RSiC复合材料。借助于X射线衍射、扫描电子显微镜、力学性能和电阻率测试等研究了熔渗温度对复合材料组成、显微结构、力学性能和导电性能的影响。采用改进型混合规则探讨了复合材料互穿网络结构和界面结合性对其导电方式的影响。结果表明:不同温度所制备的复合材料主要组成均为SiC、MoSi2和Cr5Si3;随着熔渗温度的升高,复合材料气孔率和体积电阻率下降,密度、抗弯强度和弹性模量提高。当熔渗温度为1 900℃时,复合材料的气孔率、密度、抗弯强度、弹性模量和体积电阻率分别为1.4%、3.5g/cm3、99.2MPa、313.60GPa和124.2mΩ·cm。当熔渗温度较低时(1 700℃),复合材料的导电方式与颗粒增强复合材料的导电方式接近,随温度升高,复合材料的导电方式与传统复合材料的导电方式差别增大。
Based on RSiC, a MoSi2 (Cr5Si3) -RSiC composite with three-dimensional interpenetrating network structure was prepared by PF-PIP and AMMI composite process. The effects of infiltration temperature on the composition, microstructure, mechanical properties and electrical conductivity of the composites were investigated by means of X-ray diffraction, scanning electron microscopy, mechanical properties and electrical resistivity tests. The influence of interfacial interpenetrating structure and interfacial bonding on the conductivity of the composites was discussed using the improved mixing rule. The results show that the composites prepared at different temperatures are composed of SiC, MoSi2 and Cr5Si3. With the increase of infiltration temperature, the porosity and volume resistivity of the composites decrease and the density, flexural strength and elastic modulus increase. The porosity, density, flexural strength, modulus of elasticity and volume resistivity of the composites were 1.4%, 3.5g / cm3, 99.2MPa, 313.60GPa and 124.2mΩ · cm when the infiltration temperature was 1 900 ℃. When the infiltration temperature is low (1 700 ℃), the conductivity of the composites is similar to that of the particle reinforced composites. With the increase of temperature, the conductive modes of the composites are different from that of the traditional composites.