Synthesis of nanocrystalline CrN by arc discharge

Abstract Nanocrystalline chromium nitride (CrN) with the cubic rock-salt structure was synthesized by the arc discharge method in nitrogen gas (N 2 ). The product was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that the nitrogen gas pressure is a crucial factor for the synthesis of cubic CrN. At relatively low N 2 pressure, cubic CrN was formed. With the increase of N 2 pressure, hexagonal Cr 2 N and metal Cr were gradually formed. It indicated that the formation of CrN apparently favors a low nitrogen pressure environment, and the diffusion of nitrogen atoms into the Cr was lowered with the increase of N 2 pressure. We explain this experimental observation in terms of the evaporation rate of anode Cr and the ionization of nitrogen.