Microstructure and corrosion behavior of Mg–Nd coatings on AZ31 magnesium alloy produced by high-energy micro-arc alloying process

Mg–Nd coatings were prepared by high-energy micro-arc alloying (HEMAA) on AZ31 magnesium alloy. The coatings were treated with Ar shielding gas in ambient atmosphere. X-ray diffraction (XRD) results showed that the phases formed of Mg–Nd coatings were similar to that of Mg–Nd electrode. The corrosion behavior of the coated AZ31 in 3.5 wt% NaCl solutions was studied by simple immersion test and potentiodynamic polarization measurement. It was found that the corrosion resistance of coated alloy was higher than that of AZ31 substrate. The corrosion potential of Mg–Nd coatings was much positive to that of AZ31 substrate. Furthermore, the corrosion resistance is bad due to the presence of defects when treated with undesired processing parameters.