Performance of Zr/3C-SiC interfaces modified by additions of Nb, Cr, Ni, Sn and Fe: First-principles studies

Coexisted covalent, metallic and ionic bonds increase difficulty in tailoring the properties of Metal/SiC interfaces by addition of alloying elements. Herein, we revealed the origin of Zr/SiC performance impacted by doping elements (X = Nb, Cr, Fe, Ni and Sn) using density functional theory. We found and clarified weighting of diverse chemical bonds acting on interfaces with different SiC terminations. Interface jointed by strong covalent bonding disadvantages vacancy formation, whereas favors the solution of doping elements, some of which even enhance the interface in turn. Synergy from covalent bonding, ion interaction and structural deformation is important in interfacial adhesion for the other interfaces jointed by weakly covalent bonding. Tensile performance cannot be deducted from the interfacial adhesion as cleavage is ignited from the weakest Zr-X metallic bonds on the side of Zr. An effort of this work aims to establish fundamental rules to help survey and improve Metal/SiC interfaces by screening alloying elements.