Interfacial bonding of chromium-doped copper/diamond composites fabricated by powder metallurgy method

Abstract

Copper/diamond composites can be used as heat-sink materials for high-power electronic devices due to their potential high thermal conductivity. However, it is challenging to obtain well-bonded interface between the copper matrix and the diamond particles. In this paper, we fabricated copper/diamond composites with [Formula: see text] wt.% of chromium additive ([Formula: see text], 3 and 7.4, and the corresponding composite was referred to as 1Cr-Cu/Dia, 3Cr-Cu/Dia and 7Cr-Cu/Dia, respectively) by hot forging of powder preforms. Results showed that only Cr3C2 interfacial layer formed between the copper matrix and the diamond particles for the 1Cr-Cu/Dia and 3Cr-Cu/Dia composites with a thickness of about 100 and 500 nm, respectively. A Cr/Cr3C2 dual layer interface formed in the 7Cr-Cu/Dia composite and its thickness was [Formula: see text]m. The coverage of diamond surface by the interface layer increased with increasing the adding amount of chromium in the composites. The 3Cr-Cu/Dia composite achieved the highest relative density and bonding strength, comparing to 1Cr-Cu/Dia and 7Cr-Cu/Dia composites, attributed to the formation of an optimal interface structure.