Adhesion strength and stability of TiB2/TiC interface in composite coatings by first principles calculation

Abstract

Properties of the TiC (111) surface, TiB2 (0001) surface, and TiC (111)/TiB2 (0001) interfaces were investigated by first-principles calculations. Additionally, the work of adhesion (Wad), interface energy (γint), and electronic structure of the TiC/TiB2 interfaces were studied. The calculated results show that the Wad of the hollow-stacked interfaces is larger than those of the center- and top-stacked interfaces. Among the interfaces of C/Ti-terminated hollow-stacked (C-HS-T), Ti/Ti-terminated hollow-stacked (Ti-HS-Ti), and Ti/B-terminated hollow-stacked (Ti-HS-B), the C-HS-T interface exhibits the largest Wad (11.43J/m2), the smallest interfacial separation d0 (1.208Å) and thus is the most stable. For the entire range of Ti chemical potential, the interfacial energy of the Ti-HS-Ti supercell was 1.04–4.59J/m2, while the interfacial energy was 0.54–0.58J/m2 and 0.45–0.49J/m2 for Ti-HS-B interface and the C-HS-T interface respectively. Furthermore, the C-HS-T interface consists of strong polar covalent bonding and weak metallic bonding, while the Ti-HS-B and the Ti-HS-Ti interface consists of primarily covalent and metallic bonding, respectively.