First-principles comparative study on diamond/carbide combinations: Interfacial adhesion and bonding nature

Joining diamond and metal is vital to expand their application scope in electronic and military industries. A metallic carbide layer will be inevitably introduced on diamond to ensure strength and wettability, its tight interfacial adhesion with diamond needs to be satisfied in priority. Here, the bonding characteristics of diamond(001)/carbide(001) interfaces were comparatively studied through first-principles calculations, wherein six experimentally possible carbides MxCy (TiC, Cr3C2, V8C7, Mo2C, ZrC, and WC) were employed. By evaluating the thermal stability, activity, and mechanical properties of bulk MxCy, as well as the corresponding interface energy and adhesion work, three outstanding interface structures (with Cr, W, and Ti) were yielded. Further analysis of electronic structures showed the interfacial bonding originated from M–C bonds and stronger CC covalent bonds. Besides, bonding strength was found to be significantly related to interfacial charge density and orbital hybridization. Overall, Cr might be the preferable carbide former with high interfacial stability and strength. This study provided atomic insights into the tailoring of diamond/carbide combination with superior interfacial compatibility to develop high-performance diamond devices.