The corrosion of Fe3Al alloy in liquid zinc

A systematic study of the isothermal corrosion testing and microscopic examination of Fe3Al alloy in liquid zinc containing small amounts of aluminum (less than 0.2 wt.%) at 450 °C was carried out in this work. The results showed the corrosion of Fe3Al alloy in molten zinc was controlled by the dissolution mechanism. The alloy exhibited a regular corrosion layer, constituted of small metallic particles (diameter: 2–5 μm) separated by channels filled with liquid zinc, which represented a porosity of about 29%. The XRD result of the corrosion layer formed at the interface confirmed the presence of Zn and FeZn6.67. The corrosion rate of Fe3Al alloy in molten zinc was calculated to be approximately 1.5 × 10−7 g cm−2 s−1. Three steps could occur in the whole process: the superficial dissolution of metallic Cr in the corrosion layer, the new phase formation of FeZn6.67 and the diffusion of the dissolved species in the channels of the corrosion layer.