Microstructure of Cu-diamond composites with near-perfect interfaces prepared via electroplating and its thermal properties

Highlights: • Nearly void-free microstructure of Cu-diamond composite • Near-perfect interfacial feature between diamond and copper matrix • Highest thermal conductivity of Cu-diamond composites by electroplating -- Abstract: Despite the increasing demands of copper matrix composites for use as thermal management, their manufacturing remains a great challenge since rigorous conditions are prerequisite, including high temperature and high pressure. Here, nearly void-free copper matrix diamond composite (Cu-diamond) with near-perfect interfaces is fabricated via electroplating. The surface and internal microstructure of Cu-diamond composites are investigated. The interfacial microstructure between copper matrix and diamond is discussed. Heat flux inside Cu-diamond composites is simulated using COMSOL software. Results indicate that the nearly void-free microstructure and near-perfect interfaces lead to the high thermal conductivity (TC) of 614.87 W m⁻¹ K⁻¹ and the low coefficient of thermal expansion (CTE) of 9.45 × 10⁻⁶ K⁻¹, both of which are comparable to that prepared by the conventional high temperature method. Remarkably, the electroplating technique is fully compatible with micromachining process, suggesting its potential application in microelectronic devices.