Abstract
In this study, cored wires and high velocity arc spraying technique (HVAS) were applied to produce Zn-Al and Zn-Al-Mg alloy coatings on low carbon steel substrates. The microstructures and mechanical properties were studied by SEM, EDS, XRD, and Vickers micro-indentor. The electrochemical corrosion behaviors of Zn-Al and Zn- Al-Mg coatings were investigated comparing with Zn and Al coatings in 5%NaCl. The results show that, Zn-Al and Zn-Al-Mg coatings have good quality of uniform microstructure and low porosity. The corrosion resistance of Al coating deteriorated rapidly after nearly 16h immersion, and then kept at a relative stable value. In the contrast, the corrosion potential of the coatings containing Zn decreased a little and then increased towards the noble potential. The potentiodynamic polarization tests show that the icorr value of Zn-Al coating changed greatly at different steps, and it trended to increase continuously which may imply that the coating is easy to be corroded. Comparatively, no obvious change had been found in the Zn-Al-Mg coating which may indicate that the corrosion resistance enhanced with the addition of Mg, and the role of Mg appears to be associated with the self sealing process. Abstract only; no full-text paper available.
