反应烧结制备碳化硅增强石墨复合材料及其性能

Properties of silicon carbide-reinforced graphite composites prepared by a reactive sintering method

以鳞片石墨和硅粉为混合原料,采用真空热压烧结工艺制备碳化硅增强石墨基复合材料。考察原料中硅粉含量对复合材料性能和结构的影响。XRD与SEM分析表明,经1900℃热压烧结后,硅粉与石墨发生原位反应生成碳化硅强化相,形成的碳化硅均匀分散在石墨片层间。随着硅质量分数从28.06%提高到37.94%,复合材料的弯曲强度从112 MPa提高至206 M Pa。此外,当硅含量低于31.46%时,复合材料的摩擦系数恒定为0.1,与纯石墨的摩擦系数相当。

Silicon carbide reinforced graphite composites were prepared by hot-pressing mixtures of flake graphite and Si powder with various mass ratios under vacuum.The micro structure and phase compositions were characterized by SEM and XRD.Results indicated that SiC,resulting from the reaction between graphite and silicon,was uniformly dispersed in the graphite matrix.The bend strength of the composites increased from 112 to 206 MPa with increasing silicon content from 28.06 to 37.94 mass%.The oxidation resistance of the composites increased with their silicon content.The coefficient of friction of the composites remainedat a low constant value of about 0.1 when the Si content was below 31.46 mass%.