Effects of boron concentration on the corrosion resistance of Fe-B alloys immersed in 460 °C molten zinc bath

In order to investigate the effects of boron concentration on the corrosion resistance of Fe-B alloys in molten zinc, Fe-B alloys, with the boron concentrations of 1.5 wt.%, 3.5 wt.% and 6.0 wt.% respectively, were dipped into a pure molten zinc bath at 460 °C and kept in different time intervals. The results show that, in comparison with 1Cr18Ni9Ti stainless steel, Fe-B alloy with 3.5 wt.%B exhibits excellent corrosion resistance, due to the dense continuous network or parallel Fe2B phase which hinders the Fe/Zn interface reaction in Fe-B alloys. The energy dispersive spectrum (EDS) results indicate that the coarse and compact δ phase with the length about 40 μm generates near the matrix of Fe-B alloy and massive ζ phase occurs close to the liquid zinc. The corrosion process includes Fe/Zn reaction and the isolation and fracture of Fe2B. The failure of boride is mainly caused by the microcrack.