Interfacial morphology and corrosion resistance of Fe–B cast steel containing chromium and nickel in liquid zinc

The interfacial morphology and corrosion resistance of low carbon Fe–B cast steels in zinc bath at 520 °C were investigated. The results show Fe–B cast steel containing high Cr and Ni exhibits the best corrosion resistance to liquid zinc. The corrosion layers are composed of Γ-Fe3Zn10, δ-FeZn10, ξ-FeZn13 and η-Zn. The corrosion behaviour of Fe–B cast steels includes the following processes: the preferential leach and dissolution of Cr and Ni, the formation of Fe–Zn compounds controlled by zinc atom diffusion, and the spalling of borides without the supporting role of α-(Fe, Cr) matrix corroded by liquid zinc.

► Fe–B steels containing Cr and Ni exhibit the best corrosion resistance in liquid zinc.
► Surface layers show gamma-Fe3Zn10, delta-FeZn10, zeta-FeZn13 and eta-Zn.
► Cr and Ni can enrich at the interface during the corrosion process.
► Corrosion processes include leaching, formation of compounds and spalling of borides.