ZnO@ZIF-8 core-shell structure nanorods superhydrophobic coating on magnesium alloy with corrosion resistance and self-cleaning

Abstract

A longstanding quest in material science has been the development of superhydrophobic coating based on a single material, without the requirement of fluorination or silane treatment. In this work, the micro-arc oxidation (MAO) coating as transition layer can effectively enhance the bonding force of the superhydrophobic coating. The semiconductor@metal organic frameworks (MOFs) core-shell structure was synthesized by a simple self-templating method, and obtained ZnO@2-methylimidazole zinc salt (ZIF-8) nanorods array on magnesium (Mg) alloy. ZnO nanorods not only act as the template but also provide Zn2+ for ZIF-8. In addition, we proved that the ligand concentration, synthesis time and temperature are the keys to the preparation of ZnO@ZIF-8 nanorods. As we expect, the ZnO@ZIF-8 nanorods array can trap air in the gaps to form an air layer, and the coating exhibits superhydrophobic properties (154.81°). Excitingly, ZnO@ZIF-8 nanorods array shown a superhydrophobic property, without the requirement of fluorination or silane treatment. The results shown that the coating has good chemical stability and self-cleaning performance. Meanwhile, the corrosion resistance has been significantly improved, Rct was increased from 1.044×103 to 1.414×106 Ω/cm2 and Icorr was reduced from 4.275×10−5 to 5.611×10−9 A/cm2. Therefore, the semiconductor@MOFs core-shell structure has broad application prospects in anti-corrosion.

Keywords

• Mg alloy
• ZnO@ZIF-8
• Coatings
• Corrosion resistance
• Superhydrophobic