Inhibition of graphitization on diamond surfaces via flash joule heating and construction of chemical bonds for tungsten metallization

Abstract

Surface metallization is a critical process for diamonds in thermal management applications. However, bottlenecks such as graphitization, inhomogeneous interfacial phases, and high interfacial thermal resistance persist during metallization. This study presents a novel strategy for tungsten coating on diamond particle surfaces within an extremely short time using flash joule heating. In situ chemical bonding of a composite consisting of W, W2C, and WC was achieved on the diamond surface, yielding a uniform and conformal coating that suppressed diamond surface graphitization, retained 93.2% of the intrinsic thermal conductivity of diamond, and resulted in an equivalent thermal conductivity of 1864.69 W m−1 K−1. The chemically bonded metallization shell introduced an equivalent interfacial thermal resistance as low as 9.11 × 10−10 m2 K W−1. Photothermal conversion cycling tests demonstrated that the chemically bonded metallization on the diamond surface possesses excellent thermal fatigue resistance. Through photothermal conversion studies and the construction of a two-node thermal relaxation model, the analysis indicates that the W, W2C, and WC interfacial phases introduce a moderate interfacial thermal resistance, which effectively suppresses instantaneous and intense heat dissipation to the environment, thereby enabling controllable and stable heat release.