(北京科技大學(xué) 材料科學(xué)與工程學(xué)院，北京 100083)
摘 要: 以磨碎中間相瀝青基石墨纖維和銅粉為原料，采用金屬有機(jī)化學(xué)氣相沉積工藝對原料纖維進(jìn)行鍍鉬處理，通過真空熱壓燒結(jié)制備鍍鉬石墨纖維/Cu復(fù)合材料，對其微觀組織及熱性能進(jìn)行檢測和分析。結(jié)果表明：纖維在垂直于熱壓方向的平面上出現(xiàn)擇優(yōu)排布，使得復(fù)合材料在二維方向上擁有較高的熱導(dǎo)率和較低的熱膨脹系數(shù)；纖維表面的Mo鍍層，燒結(jié)過程中部分與纖維反應(yīng)生成連續(xù)的Mo2C層，能有效改善纖維與金屬基體的界面結(jié)合，進(jìn)而促進(jìn)復(fù)合材料熱性能的改善。當(dāng)纖維體積分?jǐn)?shù)為35%~55%時，復(fù)合材料二維方向的熱導(dǎo)率在367~382 W/(m·K)之間，熱膨脹系數(shù)為4.2×10-6~8.6×10-6 K-1，可以很好地滿足大功率電子器件對封裝材料的散熱及匹配性要求。
關(guān)鍵字: 石墨纖維/Cu復(fù)合材料；鉬鍍層；微觀組織；熱導(dǎo)率；熱膨脹
（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
