One-step preparation of color-tuned surface coatings on magnesium alloy with corrosion resistance

Nowadays, few works have been undertaken to explore the anti-corrosion coatings with tunable surface colors. In order to further expand the industrial application of magnesium alloy, a facile one-step hydrothermal method was applied to AZ91D magnesium alloy to obtain anti-corrosion coatings with diversified colors. The formation mechanism was discussed, and the corrosion resistance of the coating was assessed by electrochemical tests, immersion tests, and salt spray tests. The results show that different coating colors such as yellow, cyan, blue and red can be obtained by varying the type and concentration of reagents. The adhesion of the coating to the magnesium alloy substrate was great, and the corrosion current density of the sample with the best anti-corrosion effect was reduced by three orders of magnitude. This method has practical significance in promoting the development of surface coloring and industrial applications of magnesium alloys. •Prepared by a simple one-step hydrothermal method, the reagents used are environmentally friendly.•The prepared coating has bright and a wide range of color and the color change is easy to control.•The coating has an excellent adhesion with the substrate.