Enhanced coating system corrosion protection of 2A14 Al alloy by modified cerium seal PEO pretreatment

A modified cerium seal PEO pretreatment was developed on 2A14 alloy and combined with an epoxy coating (EP) to form a duplex coating system. The PEO coating was effectively sealed by cerium hydroxides and oxides , and also acted as a controlled release vessel for the cerium salt corrosion inhibitor , and significantly improved the adhesive strength of the EP. The results of electrochemical tests and immersion experiments show that the coating system pretreated with the modified cerium seal PEO exhibits excellent long-term corrosion resistance and active protection. This is attributed to the physical barrier of insoluble cerium-based compounds and sensitive pH-responsive deposition.