Corrosion protection utilizing Ag layer on Cu coated AZ31 Mg alloy

•Corrosion protection by additional Ag with Cu electrodeposited on AZ31 is reported.•Single electrodeposited Cu on AZ31 has many crevices.•Additional Ag layer between two Cu layers can decrease the number of imperfections.•Triple-layer coating of Cu/Ag/Cu shows most efficient corrosion protection of AZ31. This study investigated the corrosion protection by electrodeposited copper layer on AZ31 Mg alloy with and without additional silver layer. The single copper layer electrodeposited on AZ31 from copper pyrophosphate bath exhibited nodular structure and crevices between the nodules which resulted in the rapid initiation of pitting corrosion. Employing an additional electrodeposited silver layer onto the copper deposited AZ31 alloy decreased the number of imperfections and changed structure of electrodeposited copper from nodular to fine particle type resulting in improved corrosion resistance. This study further revealed that triple-layer coating of Cu/Ag/Cu exhibited the most efficient corrosion protection of AZ31 Mg alloy.