Effect of laser treatment on the corrosion behavior of AZ31 Mg alloy pre-sprayed by WC-Co-Cr powder

In this Article, AZ31 magnesium alloy pre-sprayed with WC-10%Co-4%Cr powder after surface melting by pulsed Nd-YAG laser was investigated to improve corrosion resistance. Chemical composition, phase and microstructure of produced composite layer by this process were studied by scanning electron microscope equipped with energy dispersive spectroscopy and X-ray diffractometry. After laser treatment different intermetallic compounds such as Cr2O3, W2C were detected in produced composite layer. This layer mainly consist of tungsten carbide particles, chromium and cobalt in Mg matrix. In this article, beside of evaluation of corrosion properties, evaluating of hardness of produced layer of laser treatment showed that hardness of AZ31 magnesium alloy has increased from about 50±5 Vickers for base alloy to about 200±10 Vickers for layer produced by laser treatment. Corrosion behavior evaluation of laser treated layer and comparison with base alloy was done by polarization test in 3.5wt.% NaCl solution and by measurement of some parameters of polarization curves was determined that corrosion resistance of laser treated sample with WC-Co-Cr powder has increased three times in comparison with base alloy.