Fabrication of diamond/copper composite thin plate based on a single-layer close packed diamond particles network for heat dissipation

High-efficiency heat dissipation is crucial for the reliability and durability of high-power electronics devices. Diamond/copper composites have drawn much attention as promising candidate materials for thermal management due to their high thermal conductivity and tunable coefficient of thermal expansion. In this work, a novel method was proposed to fabricate a thin plate of diamond/copper composite based on the construction of single-layer close packed diamond particles network. The composite with a sandwich structure was prepared by press-brazing method, which is cost-effective for both preparation and post-processing. The microstructures of the composite plate containing diamond, AgCuTi filler and Cu were examined. The influence of diamond particle size on thermal conductivity, coefficient of thermal expansion, and mechanical properties were also experimentally measured and theoretically simulated. The results show that a single-layer close packed diamond particles network is densely brazed between copper layers to form a composite thin plate. The interface TiC layer is in-situ formed between diamond and AgCuTi matrix. With increase in the diamond particle size to 1200 μm, thermal conductivity of 552.7 W⋅m−1⋅K−1, coefficient of thermal expansion of 10.1 × 10-6 K−1, and flexural strength of 204.3 MPa are achieved, which are in agreement with the theoretical simulated results. As a heat spreader substrate, the heat dissipation ability of diamond/Cu composite is increased by 5.7 °C in comparison with pure Cu plate. Finite element analysis and testing of actual scenarios further confirm the excellent thermal performance of the sandwich structured diamond/Cu composite thin plate, making it a prospective candidate for thermal management.