(北京科技大学 材料科学与工程学院，北京 100083)
摘 要: 以磨碎中间相沥青基石墨纤维和铜粉为原料，采用金属有机化学气相沉积工艺对原料纤维进行镀钼处理，通过真空热压烧结制备镀钼石墨纤维/Cu复合材料，对其微观组织及热性能进行检测和分析。结果表明：纤维在垂直于热压方向的平面上出现择优排布，使得复合材料在二维方向上拥有较高的热导率和较低的热膨胀系数；纤维表面的Mo镀层，烧结过程中部分与纤维反应生成连续的Mo2C层，能有效改善纤维与金属基体的界面结合，进而促进复合材料热性能的改善。当纤维体积分数为35%~55%时，复合材料二维方向的热导率在367~382 W/(m·K)之间，热膨胀系数为4.2×10-6~8.6×10-6 K-1，可以很好地满足大功率电子器件对封装材料的散热及匹配性要求。
关键字: 石墨纤维/Cu复合材料；钼镀层；微观组织；热导率；热膨胀
（School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:Mo-coated graphite fiber/Cu composites were fabricated by vacuum hot-press sintering with milled mesophase pitch-based graphite fibers and Cu powder. The molybdenum coatings on the fibers were obtained via metal organic chemical vapor deposition technique. Microstructure and thermal properties of the composites was examined. The results show that the fibers have a preferential orientation in the plane perpendicular to the pressure axis, which leads to the composites possess higher thermal conductivities and lower coefficients of thermal expansion (CTEs) at the 2-D direction. The Mo coating reacts with graphite fiber, and part of which forms a continuous Mo2C layer during densification process, which can improve the interfacial bonding between the fiber and metal matrices effectively, and then improve the thermal properties of the composites. The composites achieve 2-D thermal conductivities between 367-382 W/(m·K) and CTEs of 4.2×10-6-8.6×10-6 K-1 with the fiber content ranging 35%-55% (volume fraction). They can commendably meet the heat dispersion and matching requirements of power electronic devices to the packaging materials.
Key words: graphite fiber/Cu composites; molybdenum coating; microstructure; thermal conductivity; thermal expansion
