Role of Al in Zn bath on the formation of the inhibition layer during hot-dip galvanizing for a 1.2Si–1.5Mn transformation-induced plasticity steel

• Published in: Applied surface science 2013-11, Vol.285, p.458-468
• Main Authors: Wang, Kuang-Kuo, Hsu, Chiung-Wen, Chang, Liuwen, Gan, Dershin, Yang, Kuo-Cheng
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Interfaces; Physics; Selective oxidation; Steel; TEM; XPS; Zinc
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2013.08.077

•Si–Mn TRIP steel are hot-dip galvanized in Zn bath containing 0.14–0.18wt.% Al.•Al2O3 and Si–Mn–Al–O are observed as evidences of the aluminothermic reaction.•Increasing Al content in Zn bath improves the galvanizability.•The steel that was covered by a thick oxide layer exhibited good galvanizability. This study investigated the interaction between the Al in the Zn bath and the surface oxides formed by selective oxidation on a 1.2Si–1.5Mn TRIP steel during hot-dip galvanizing. XPS and TEM were employed for characterization. The results indicated that the amorphous xMnO·SiO2 oxide could react with Al to form a Si–Mn–Al-containing oxide. The crystalline MnSiO3 and Mn2SiO4 oxides could be largely reduced by Al to form holes in the oxide film. Consequently, the steel covered by a layer of mixed xMnO·SiO2 and MnSiO3 could form a continuous Fe2Al5 inhibition layer and showed the highest galvanizability among the three samples examined.