Investigating the Hardness Properties of Superhard Materials (B-C-N)

Abstract

We present the computational report with the first-principles calculations based on the DFT concepts, which were performed to solve the Kohn-Sham equations by the self consistent field method. The crystal structures of BC2N in the Pmm2 and C2/m phases were initially observed. The energy-calculation result indicated that the Pmm2 phase is a more stable phase due to the minimum free energy. Besides, the elastic constants were calculated so that the bulk modulus and hardness will be analyzed between the two phases. The elastic constants of both phases of BC2N exhibited the brittle-material condition. We also proposed the positive value of Vickers hardness that the BC2N in the Pmm2 phase gave the hardest condition at 74.8 GPa, while it was just found at 32.2 GPa in the C2/m phase.