The effect of standoff distance on the electrochemical corrosion behavior of Zn-Al pseudo alloy coating by arc spray on low carbon steel in a seawater environment

An experimental study of Zn-Al pseudo alloy coatings prepared by twin dissimilar Zn and Al wires using the arc spray process at a different standoff distance, in order to protect low carbon steel substrates from marine corrosion has been undertaken in the present paper. The corrosion behavior of a Zn-Al pseudo alloy coating in a seawater solution collected from the Mediterranean Sea (Algerian coast), was evaluated by open circuit potential (OCP), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) tests. The obtained results reveal that all prepared Zn-Al pseudo alloy coatings can protect the substrate, but the coating obtained at 100 mm standoff distance with 55.73% Zn and 44.27% Al presents a better performance in corrosion protection when exposed to seawater solution compared to Zn-Al pseudo alloy coatings prepared at 120 and 140 mm standoff distances, respectively. A strong correlation is also observed between corrossion data, porosity fraction, and hardness.