Investigation on WC/TiC interface relationship in wear-resistant coating by first-principles

Abstract

Abstract The adhesion strength between WC and TiC, materials commonly employed in wear resistant coatings, is determined by their interfacial properties. In this work, the adhesion energy, interfacial energy, electronic structure and bonding of WC/TiC interface were calculated by using first-principles method. The results show that the work of adhesion ( W ad ) of the HCP (interfacial Ti(C) atom located on top of C(W) atom in second layer of WC) stacking interface is larger than those of the Hole (interfacial Ti(C) atom located on top of vacancy of WC), OT (interfacial Ti(C) atom located on top of C(W) atom in surface of WC) stacking interfaces for all the terminations. For the three HCP stacking interfaces, the W-HCP-C interface exhibits the largest W ad , which is 10.16 J/m 2 . The C-HCP-Ti interface is followed, which is 7.75 J/m 2 . While the W-HCP-Ti interface exhibits the smallest W ad , which is 2.64 J/m 2 . The interfacial separation d 0 exhibits an opposite trend. Over the entire range of C chemical potential (Δμ C ), the interfacial energy of W-HCP-C interface is in the range of 1.03–1.43 J/m 2 , and the interfacial energy of C-HCP-Ti interface is 1.06–1.46 J/m 2 . While that of W-HCP-Ti interface is 3.78–4.18 J/m 2 . It is obvious that the W-HCP-C interface and C-HCP-Ti interface exhibit smaller interfacial energy, which are more stable than the W-HCP-Ti interface. The W-HCP-C interfacial bonding is a mixture of strong covalent bond and partially ionic bond. The bonding of C-HCP-Ti interface is covalent. While the W-HCP-Ti interfacial bonding is mainly metallic.