Preparation and properties of hydrophobic micro-arc oxidation/layered double hydroxide composite coating on magnesium alloy

• Published in: Surface & coatings technology 2023-12, Vol.475, p.130113, Article 130113
• Main Authors: Ba, Zhixin, Wang, Yongmin, Sun, Tianyi, Jia, Yongqiang, Zhang, Lingling, Dong, Qiangsheng
• Format: Article
• Language: English
• Subjects: Corrosion resistance; Hydrophobic; LDH; MAO; Mg alloy
• ISSN: 0257-8972
• DOI: 10.1016/j.surfcoat.2023.130113

The rapid degradation rate of Mg alloys limited clinical applications. Layered double hydroxide (LDH) compounds are developed as surface coatings for biomedical magnesium (Mg) alloys. In this work, LDH intercalated with myristic acid ion was in-situ formed on micro-arc oxidized ZK60 alloy using a simple one-step hydrothermal process for controllable and stable degradation. Micro-pores in micro-arc oxidation coating (MAO) were sealed by LDH, and the surface became hydrophobic. With hydrothermal treatment time of 8 h, the MAO/LDH composite coating exhibited the maximum hydrophobicity with a contact angle of about 135.6° and the lowest corrosion current density of about 3.51 × 10−9 A·cm−2. During in-vitro immersion, MAO/LDH composite coating became hydrophilic from hydrophobic, but also provided a good protective ability for Mg alloy. This study provides new insights into the surface modifications of Mg alloys for hydrophobic-hydrophilic transition demand. •A hydrophobic LDH was formed on MAO coating via a one-step hydrothermal process.•Micro-pores in MAO were sealed by hydrophobic LDH.•MAO/LDH composite coating exhibited good hydrophobicity and anti-corrosive properties.•MAO/LDH composite coating displayed a hydrophobic-hydrophilic transition during immersion.