Effective PEO/Silane pretreatment of epoxy coating applied on AZ31B Mg alloy for corrosion protection

[Display omitted] •Hybrid silane with different volume ratios of TEOS/APTES as intermediate layer.•Chemical bond between PEO coating and silane layer.•Covalent bond between silane layer and epoxy coating.•Best protective properties for coating systems with T50/A50 layer.•Increasing adhesion strength of epoxy coating with silane as intermediate layer. In this study, a PEO/Silane/Epoxy three-layer coating was introduced as an effective protection system for the preservation of Mg alloy. Cerium nitrate was used as an inhibitor in the (plasma electrolytic oxidation) PEO coating structure and was coated with a silane layer containing various volume ratios of tetraethoxysilane (TEOS) and γ-amino propyltriethoxysilane (APTES). Electrochemical impedance spectroscopy (EIS) and adhesion tests were performed on three-layer coating samples. Protective properties of PEO coating as well as PEO/Epoxy coating was improved by applying the silane film as the interfacial layer, with the T50/A50 saline film showing the best protective performance.