Comparative research on the interfacial properties of Ni/diamond and Ni/graphene interface with Cr, B, and Si additions by first-principles calculation

Abstract

Diamond and graphene (Gr) with excellent hardness and strength are the ideal reinforcement for WC-based ceramics due to the wear resistance and toughness enhancement effect. For the promising diamond-graphene/WC-Ni composite, one of the major challenges is the intrinsic difference of interfacial bonding mechanism between diamond/Ni and graphene/Ni interfaces that makes it difficult to obtain desired mechanical bonding properties simultaneously. To address this issue, the adhesion and electronic properties of the Ni (111)/diamond (111) and Ni (111)/graphene (001) interfaces, together with the impact of Cr, B, and Si doping on the mechanical and fracture properties of the interfaces are analyzed comparatively through first-principles calculations in this work. Adhesion energy calculations demonstrate that the bonding strength of Ni/diamond interface is 4.5 times greater than that of Ni/Gr interface, and the addition of Cr and B atoms can increase the adhesion energy of Ni/diamond interface by 19.6 % and 36.7 %, and Ni/Gr interface by 284 % and 222 % respectively. Moreover, the calculations of electron density, charge density difference, and density of states suggest that Cr and B atoms facilitate the establishment of stronger chemical bonds at the interface. First-principles computational tensile tests show the tensile strength of Ni/diamond and Ni/Gr increases separately by 1.5 % and 62.2 % after Cr doping, and the tensile strength of Ni/diamond models is 2.5 times greater than that of Ni/Gr models.