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 (Cr _3 C _2 , Cr _7 C _3 and Cr _23 C _6 ) 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. Cr _3 C _2 exhibits the strongest covalent character while Cr _7 C _3 displays the highest metallicity. Cr _3 C _2 showed the highest stability among the chromium carbide phases. In the Fe-substituted chromium carbides (Cr _2 FeC _2 ), the site preference of Fe in Cr _3 C _2 system has been reported. In Fe-substituted chromium carbides also show both of metallic and covalent character and Cr _2 Fe3C _2 is found to be the most stable Fe-substituted chromium carbide system.