Bonding and Adhesion at the SiC/Fe Interface

Ceramics such as SiC have the potential to act as protective coatings, primarily due to their high melting points and wear resistance. We use periodic density functional theory (DFT) within the generalized gradient approximation (GGA) to calculate the adhesion strength between SiC and Fe, for Si- and C-terminations of SiC(100) and two surfaces of Fe: (100) and (110). We predict a maximum ideal work of adhesion of 6.51 J/m(2) at the SiC(100)/Fe(110) interface for C-Fe interfacial bonding, which is stronger than the traditional chrome coating's adherence to Fe. We characterize the interfacial bonding via local densities of states and electron density difference analysis and find strong covalent bonding and some evidence of metallic bonding between Si (C) and Fe. Our results suggest that SiC might prove useful as a thin adhesion layer in a multilayer protective coating for steel.