Damaging micromechanisms in hot-dip galvanizing Zn based coatings

Hot dip galvanizing processing has not changed in over 200. years. Recently, the attention to environmental issues has led to new solutions to traditional protection technique, introducing innovative ways to optimize different coating properties. Hot-dip galvanizing is a conventional technological process suitable for protecting iron based alloys. It is usually characterized by the presence of Pb due to its ability to fluidize the bath. However, contents of Pb both in finished and in semi-finished product coatings can be harmful to human health. In many legislative areas, recent laws prohibit the additions of Pb. In order to improve the fluidizing of zinc baths, new metallic elements are used (e.g. Sn additions), but other metallic elements can also be used to optimize different properties of zinc based coatings. In this work, an ipersandelin steel was used in order to investigate the effect of Cu, Sn and Ti additions in the coatings baths. Growth and bending resistance in intermetallic phases have been studied to analyze the damaging micromechanisms. Results are also compared with the results of pure Zn and Zn-Pb bath coatings. © 2014 Elsevier Ltd.