The process of electroplating with Cu on the surface of Mg–Li alloy

• Uniform and dense coating with nodular structures is electroplated on substrate.
• Four optimum process parameters of electroplating are affirmed by orthogonal test.
• Solution temperature is the most influential on electroplating among four factors.
• Corrosion and wear resistance have been improved notably, and adhesion is very firm.

Mg–Li alloy is a potential applied material because of its ultra-low density. Its poor corrosion and wear resistance hinder the expansive applications. In this research, an electroplating mean was carried to obtain a Cu-coating on the Mg–Li alloy. The main factors that influence the electroplating effect were examined through orthogonal experiments, and the determined optimum processing parameters by electrochemical tests are as follows: concentration of main salt is 50 g/L, current density is 2 A/dm2, solution temperature is 40 °C and electroplating time is 30 min, respectively. Afterwards, surface and cross-section morphology feature and elemental composition were characterized by SEM and EDS, and surface phase composition was characterized by XRD. Corrosion resistance and adhesion property of the coating were investigated by electrochemical tests and cross-cut tests. Results show that there exists the uniform, dense and pure Cu coating with nodular structures on the surface of Mg–Li alloy. Meanwhile, the corrosion resistance and adhesion properties are improved and the hardness value is increased after electroplating with Cu, which concludes that the coating can provide protection for Mg–Li alloys.