Elaborating highly thermal-conductive diamond/Cu composites by sintering intermittently electroplated core-shell powders

Abstract

Actuated by the needs of high power electronic devices heat dissipation, diamond/Cu composites with excellent thermal dissipation properties have been considered as the next generation of thermal management material. Herein, an easy-to-operate intermittently electroplated method is developed for coating micro-sized particles and successfully applied to prepare Cu-coated diamond powders for the first time. The Cu coating is covered evenly and densely on the diamond particles surface, and its volume fraction in diamond/Cu composite powders could be precisely controlled by adjusting the plating time. The dense diamond/Cu composites bulks with varied Cu volume fractions were obtained by hot-press sintering process. The as-sintered microstructures of diamond/Cu bulks present that diamond particles are bonded strongly by Cu shell layer, which is conducive to promoting densification capacity. The maximal diamond/Cu composite bulk possesses high thermal conductivity of 638 W/(m·K) and low coefficient of thermal expansion (CTE) of 4.11 × 10−6/K at 55 vol% diamond. The bending strength of 45 vol% diamond/Cu composite reaches 276 MPa. The combination of these excellent thermal and mechanical properties, coupled with the simple, efficient powder-preparation process, demonstrate the large potential of intermittently electroplated method applying in the development of thermal management material.