Interface engineering in hexagonal boron nitride/metal systems: from in situ growth to metal matrix composites
Hexagonal boron nitride (h-BN) possesses a unique combination of high thermal conductivity, superior hardness, outstanding chemical stability, and a wide bandgap (~5.5–6 eV), rendering it indispensable for high-temperature lubrication, thermal management, electronic devices, and superhard tools. The performance of h-BN/metal systems is fundamentally governed by interfacial characteristics, including atomic structure, chemical bonding, electronic band alignment, and defect states. This review systematically analyzes interface engineering in h-BN/metal systems via two primary routes: in situ growth and ex situ compositing. During in situ growth of h-BN thin films on metal substrates (e.g., Cu, Ni), the metal substrate and growth conditions exert multifaceted influences on film quality through interfacial coupling, directly impacting contact resistance, operational stability, and noise characteristics in devices such as field-effect transistors and photodetectors. For ex situ preparation of h-BN/metal composites, interface construction is synergistically determined by h-BN dimension, matrix properties, and fabrication process. Empirical studies on Mg/BN and Cu/BN composites demonstrate that interface engineering, including surface modification and transition layers (e.g., TiN), significantly enhances mechanical and tribological properties. This review elucidates fundamental principles and unique mechanisms of h-BN/metal interface control, providing strategic insights for designing advanced h-BN-based functional devices and composites.