Abstract: The poor wettability between diamond and copper greatly affects the thermal conductivity of composite materials. To improve diamond-copper wettability and strengthen interfacial bonding, tungsten (W) was deposited onto diamond surface by a molten salt method to achieve the surface metallization of diamond, and the influences of molten salt plating temperature and holding time on the diamond coating were investigated. Subsequently, W-coated diamond particles were consolidated into Cu matrix composites by spark plasma sintering (SPS), and the correlations between molten salt coating parameters and the thermal conductivity of diamond/Cu composites were systematically explored. The results indicated that high plating temperature and appropriate holding time were beneficial for the formation of high-quality tungsten carbide coatings on diamond surfaces. At a coating temperature of 1000℃ and a holding time of 90 min, diamond reacted with tungsten powder to form a uniform, intact and nearly defect-free tungsten carbide (WC) coating. The formed coating enhanced the interface bonding between diamond particles and copper matrix, thereby effectively improving the thermal conductivity of diamond/Cu composites. The prepared diamond/Cu composite achieved a maximum thermal diffusion of 208.77 mm2/s and a peak thermal conductivity of 579.52 W/(m?K). Plating temperature and holding time of diamond had a significant impact on the thermal conductivity of composite materials. Optimizing these two parameters enabled the construction of a thin, continuous, stress-matched and low thermal resistance interfacial layer, maximizing the thermal conductivity of diamond/Cu composites. This work provides a theoretical basis for optimizing the thermal conductivity of diamond/Cu composites and the selection of the interface carbide layer.

Key words: diamond, salt bath plating, W-coating, composites, thermal conductivity

摘要： 金刚石和铜之间较差的润湿性极大地影响了复合材料的导热性能，为改善金刚石与铜之间的润湿性并提高导热性能，本研究通过盐浴镀法在金刚石表面镀钨(W)实现金刚石的表面金属化，并采用放电等离子烧结法制备金刚石/铜复合材料，研究盐浴镀镀覆温度、保温时间对金刚石镀层及金刚石/铜复合材料导热性能的影响。结果表明，金刚石表面形成的碳化钨(WC)镀层可增强金刚石颗粒与铜基体之间的界面结合，有效提高金刚石/铜复合材料的导热性能。当镀覆温度为1000℃、保温时间为90 min时，金刚石/铜复合材料的热扩散系数可达208.77 mm2/s，热导率可达579.52 W/(m?K)，具有最好的导热性能。金刚石的镀覆温度和保温时间对复合材料的热导率均有显著影响，只有实现温度-时间耦合优化，才可构筑薄而连续、应力匹配的低阻界面，实现金刚石/铜复合材料热导率最大化。

关键词: 金刚石, 盐浴镀, W镀层, 复合材料, 热导率