In situ preparation of MAO/TiO2 composite coating on WE43 alloy for anti-corrosion protection

• Published in: Vacuum 2022-03, Vol.197, p.110835, Article 110835
• Main Authors: Zhang, Shiliang, Guo, Wei, Liu, Ning, Xia, Chaoqun, Wang, Hongshui, Liang, Chunyong
• Format: Article
• Language: English
• Subjects: Corrosion resistance; Magnesium alloy; MAO/TiO2 composite coating; Sol–gel processes
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2021.110835

Microarc oxidation (MAO) coatings have attracted a lot of researchers because of their excellent adhesion to the substrate alloys. However, the porous structure of the MAO coating allows aggressive ions to invade the MAO/substrate interface and deteriorates the anti-corrosion of the coating. Herein, to seal the micropores and improve corrosion protection, a dense and biocompatible TiO2 layer was successfully developed on the MAO coating of the biodegradable WE43 alloy. Characteristics of the composite coating were analyzed, and then the degradation behavior of the samples was investigated. Results demonstrated that the micro-defects in MAO coating were effectively sealed by TiO2. Compared with WE43 alloy, the corrosion current density of the sample coated with MAO/TiO2 was reduced by three orders of magnitude, indicating that the composite coating has an excellent anti-corrosion behavior. In addition, the anti-corrosion mechanism of MAO/TiO2 composite coating was also suggested. •TiO2 film was prepared on MAO-coated WE43 alloy by simple spin-coating and heat treatment processes.•TiO2 film effectively sealed the micropores in the MAO coating.•TiO2 film significantly improved the corrosion resistance of MAO-coated WE43 alloy.