Preparation of high thermal conductivity copper–diamond composites using molybdenum carbide-coated diamond particles

Molybdenum carbide (Mo2C) coatings on diamond particles were proposed to improve the interfacial bonding between diamond particles and copper. The Mo2C-coated diamond particles were prepared by molten salts method and the copper–diamond composites were obtained by vacuum pressure infiltration of Mo2C-coated diamond particles with pure copper. The structures of the coatings and composites were investigated using X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The results indicated that the Mo2C coatings effectively improved the wettability between diamond particles and copper matrix, and Mo2C intermediate layers were proved to decrease the interfacial thermal resistance of composites. The thermal conductivity of the composite reached 608 Wm−1 K−1 with 65 vol.% Mo2C-coated diamond, which was much higher than that with uncoated diamond. The greatly enhanced thermal conductivity is ascribed to the 1-μm-thick Mo2C coatings. Mo2C coatings on diamond particles are proved to be an effective way to enhance the thermal conductivities of copper–diamond composites.