Optically transparent Li–Al–CO3 layered double hydroxide thin films on an AZ31 Mg alloy formed by electrochemical deposition and their corrosion resistance in a dilute chloride environment

An optically transparent Li–Al–CO3 layered double hydroxide (LDH) film was formed on an AZ31 substrate by applying DC voltage between the cathode (AZ31) and the anode (stainless steel) in a Li+/Al3+ aqueous solution. The film thickness increased with electrolysis time. The LDH-coated sample exhibited low corrosion rate in NaCl solution, which was consistent with the results from long-term corrosion testing in a high-humidity environment. The LDH film exhibited good corrosion performance, which mainly resulted from its high hydrophobicity and its increased surface pH value during corrosion testing.

► A hydrotalcite film has been formed electrochemically on AZ31.
► The hydrotalcite film is optically transparent.
► The film shows long-term corrosion resistance in high-humidity environment.
► The hydrotalcite film is hydrophobic with a water contact angle of 130°.