Microstructure and interface characteristics of Fe–B alloy in liquid 0.25 wt.% Al–Zn at various bath temperatures

Highlights: ► Bath temperature affects interfacial structures and corrosion rate of Fe–B alloy. ► Fe2Al5Znx can transform into FeAl3Znx when bath temperature exceeds 520 °C. ► Corrosion process is controlled by Al and Zn inter-diffusion. ► Spalling of Fe2B generates owing to hot cracks with increasing bath temperature. - Abstract: The microstructure and interface characteristics of Fe–B alloy in liquid 0.25 wt.% Al–Zn at various bath temperatures have been investigated. The results dominate that bath temperature can strongly affect corrosion rate and interfacial structures of Fe–B alloy in liquid 0.25 wt.% Al–Zn. The phase transformation from Fe2Al5Znx intermetallic compound to FeAl3Znx intermetallic compound can occur at the corrosion interface when bath temperature exceeds 520 °C by means of compositional self-adjustment, which is attributed to thermodynamics and kinetics of the system. Corrosion process and its interface are mainly controlled by Al and Zn inter-diffusion with the increase of bath temperature. The spalling of Fe2B generates with the increasing bath temperature owing to the presence of cracks during hot corrosion.