Electrodeposition of copper coating on AZ31 magnesium alloy

Abstract

Magnesium and its alloys have limited wide applications due to their poor corrosion resistance. In this study, copper coating used as a plating nickel substrate was directly electrodeposited on AZ31 magnesium alloy from copper hydroxide and citrate bath with the addition of fluorine ion and additives using direct current. Copper coating was characterised using scanning electron microscopy (SEM) for observing surface and cross-section morphology of copper coating, by using scratched grid test for examining adhesion strength, by using immersion test for examining corrosion resistance. Observation by SEM showed that copper coating was the typical spherical nodular structure, thus providing uniform and dense appearance of copper coating. Adhesion strength test showed that copper coating was not peeled from AZ31 magnesium alloy when copper coating scratched to form grid was pulled using adhesive tape. Immersion test in 5% (m/v) NaCl solution revealed that copper coating is a protective layer on the AZ31 magnesium alloy.