Mechanical properties, electronic structures, and debye temperature of Ni x B y compounds obtained by the first principles calculations

Abstract

Mechanical properties, electronic properties, and Debye temperatures of Ni x B y (Ni 3 B, Ni 2 B, Ni 4 B 3 and NiB) compounds were obtained by the first principles calculations based on the density functional theory (DFT). The results showed that the formation enthalpy of the Ni x B y compounds were stable with negative formation enthalpy. NiB had the largest B, G, and E, and the smallest υ; it also had the highest hardness (10.8 GPa) and Debye temperature (681.8 K). Ni 4 B 3 had the strongest anisotropy. It was found that the valence bonds of the Ni x B y compounds studied were composed of both metal bond and covalent bond, and the mechanical properties and Debye temperature of the Ni x B y compounds increased with the increase of the B atomic ratio.