Preparation of micro-diamond/copper composite foils by direct current electro-deposition method and its properties

The tungsten coated micro-diamond reinforced copper composite foils were prepared by direct current electro-deposition method. The effect of current density and size of micro-diamond on the microstructure and thermal conductivity were investigated. The experimental results showed that under the optimum current density of 133.3 mA/cm2 and diamond size with 100/120, the composite foils had the highest thermal conductivity (TC) of 509.7 W·m−1·K−1, increasing about 28.4 % comparing with the pure copper (397 W·m−1·K−1). Meanwhile, its micro-hardness with an average value of 309.5 HV was achieved. It also had the best corrosion resistance with a corrosion potential of −0.512 V. The diamond/copper matrix composites prepared under the optimum process parameters were subjected to thermal cycling (−196 °C ∼ 200 °C), and the TC value showed a decreasing trend with the increase in the number of cycles, and the TC of composites decreased drastically after cycling 20 times, to only 306.5 W·m−1·K−1, which was 60.5 % of that for the composites without thermal cycling. The mechanism of its microstructure-properties relationship was further discussed. It is expected that this work could provide an alternative method to preparing diamond/copper composites with high TC and thermal cycling stability. [Display omitted] •The tungsten coated micro-diamond reinforced copper composite foils were prepared by direct current electrodeposition method.•Multiple characterization methods were used to characterize the thermal and mechanical properties of the samples.•The tungsten coated micro-diamond reinforced copper composite foils showed good thermal stability.