First‐Principles Study on the Influence of Atomic Coordination on the Adhesion Strength and Stability of FeCr2O4/α‐Fe Interface

ABSTRACT To investigate the effect of atomic coordination on the stability and adhesion strength of the FeCr 2 O 4 /α‐Fe interface, four different interface models (O top‐site, Cr top‐site, Fe 1 top‐site, and Fe 2 top‐site) are developed based on first‐principles density functional theory. The results indicate that the FeCr 2 O 4 /α‐Fe interface primarily consists of Fe me ‐O ox mixed ionic‐covalent bonds and Fe me ‐Fe ox metallic bonds, with the Fe me ‐O ox bonds dominating the interfacial adhesion strength. Compared with the Fe 2 top‐site interface, the Fe 1 and Cr top‐site interfaces exhibit low charge accumulation and longer Fe me ‐O ox bonds, which results in weaker Fe me ‐O ox bonding strength at the interface. The orbital hybridization between Fe and O atoms at the Fe 2 top‐site interface is stronger than that at the Cr top‐site interface, leading to greater structural stability for the Fe 2 top‐site interface. These results could have practical significance for understanding the failure of the oxide film on ferritic heat exchangers.