The corrosion behavior of plasma sprayed Fe2Al5 coating in molten Zn

Aluminum coating was plasma sprayed on Fe-0.14–0.22 wt.% C steel substrate, and heat diffusion treatment at 923 °C for 4 h was preformed to the aluminum coating to form Fe2Al5 inter-metallic compound coating. The corrosion mechanism of the Fe2Al5 coating in molten zinc was investigated. SEM and EDS analysis results show that the corrosion process of the Fe2Al5 layer in molten zinc is as follows: Fe2Al5 → Fe2Al5Znx (η) → η + L(liquid phase) → L + η + δ(FeZn7) → L + δ → L. The η phase and the eutectic structure (η + δ) prevent the diffusion of zinc atoms efficiently. Therefore the Fe2Al5 coating delays the reaction between the substrate and molten zinc, promoting the corrosion resistance of the substrate.