Preparation of Superhydrophobic Hydroxyapatite Coating on AZ31B Magnesium Alloy with Self-Cleaning Anti-Corrosion Properties and Excellent Stability

The poor corrosion resistance of magnesium alloy limits its applications. The preparation of superhydrophobic coating on its surface can effectively improve the corrosion resistance, and the self-cleaning performance of superhydrophobic coating can also enhance the anti-fouling performance of magnesium alloy. In this study, the flake superhydrophobic hydroxyapatite (HA) coating with micro-nano scale was prepared on the magnesium alloy surface by electrodeposition, chemical immersion and stearic acid low-energy modification. The measured water contact angle on the coating surface was 160.21° and the sliding angle was 2.5°. The stability tests indicated that the coating has excellent high-temperature resistance and mechanical stability, which opened up the possibility of high-temperature service. The electrochemical test showed that the superhydrophobic HA coating significantly enhanced the corrosion resistance of the magnesium alloy. The effectiveness of the corrosion inhibition was up to 99%, which provided a protective shield for the substrate. This work expects to further broaden the application field of magnesium alloys. Graphical Abstract