Track: Material Engineering
Abstract
Hot Dip Galvanizing is one of the oldest and more used methods to protect steels substrates from corrosion due to the good corrosion resistance of the Zn coatings. This work studies the effect of the addition of small amounts of Ni to hot-dip galvanizing bath on the corrosion behaviour of hot-dipped Zn rich coating using open circuit potential (OCP), electrochemical noise (ENM) and electrochemical impedance spectroscopy (EIS). The results show that the Zn-Ni coating alloys exhibit nobler potentials and low current density indicating the increase of the corrosion resistance of the sample due to the protective effect provided by the oxides formed on Zn-Ni coating alloys. However, the corrosion products allow the mass transfer of aggressive species showing a semi-infinite behaviour. The protective effect shows a relationship with the Ni amount employed. The hot-dip method for deposition of Zn-Ni coatings employing 0.5% Ni exhibit the best performance.