Electroless plating of copper on AZ31 magnesium alloy substrates

Chemical surface preparation for copper film on magnesium alloy by both electroless plating and organic coatings was studied. Organic coating was made by immersing the samples into an organosilicon heat-resisting varnish. A subsequent metallization process verified the applicability of this method. In this method, the organic coating acted as an interlayer between the substrate and copper film. When the reaction started, copper deposited directly onto the interlayer surface. X-ray diffraction and SEM analysis were used to understand the composition and morphology of the interlayer and copper film. The copper film has a rather perfect crystalline structure. And the result of the cross-cut test indicates the adhesion between the substrate is good enough. The potentiodynamic polarization curves for corrosion studies of coated magnesium alloys were performed in a corrosive environment of 3.5 wt% NaCl at neutral pH 7. The result reveals that compared with the substrate, the corrosion resistance of the coated AZ31 magnesium alloys increases distinctly. Moreover, the copper film has perfectly antibacterial and decorative properties. The method proposed in this work is environmentally friendly: non-toxic chemicals are used. In addition, this provides a new concept for plating the metals, which are considered difficult to plate due to high reactivity.