Structural and electronic properties of chromium carbides and Fe-substituted chromium carbides

Chromium carbides are coated over base metal (Fe) to increase wear and corrosion resistance. The electronic structure and bonding properties for chromium carbide bulk phases (Cr3C2, Cr7C3 and Cr23C6) and Fe-substituted chromium carbides is investigated using Density Functional Theory (DFT). The bonding in these carbides has been interpreted in the form of partial density of states, electron density distribution and Mulliken population method. Cr3C2 exhibits the strongest covalent character while Cr7C3 displays the highest metallicity. Cr3C2 showed the highest stability among the chromium carbide phases. In the Fe-substituted chromium carbides (Cr2FeC2), the site preference of Fe in Cr3C2 system has been reported. In Fe-substituted chromium carbides also show both of metallic and covalent character and Cr2Fe3C2 is found to be the most stable Fe-substituted chromium carbide system.