Corrosion behaviors of low carbon steel, SUS310 and Fe–Mn–Al alloy with hot-dipped aluminum coatings in NaCl-induced hot corrosion

The hot corrosion behaviors of hot dip aluminized low carbon steel, SUS310 and Fe–Mn–Al–Cr–Si–C alloy with 9 mg cm−2 of NaCl deposition were studied at 900 °C for 1–144 h in dry air. A preoxidation of as-dipped specimens at 900 °C for 2 h was also conducted. The formation of an aluminized layer and self-healing potential are responsible for the better hot corrosion resistance of as-dipped low carbon steel and SUS310. Owing to the high solubility of aluminum in the Fe–Mn–Al–Cr–Si–C alloy, the coated aluminum diluted rapidly and complex phase transformations were induced by the interdiffusion of the aluminum and alloy matrix. A nitrogen-attacked zone in the aluminized layer was also observed. The corrosion resistance of hot-dip aluminum coated Fe–Mn–Al–Cr–Si–C alloy was thus degraded. Preoxidation treatment increased the thickness of the aluminized layer, yet reduced the corrosion resistance of three alloy systems due to the formation of microcracks during the cooling and the further heating to elevated temperature.