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.