Self-healing corrosion protective coatings for magnesium alloys by modifying anodising layers with corrosion inhibitors
D. Tabatabai, S. Janke, F. Feil, P. Thissen, G. Grundmeier, W. Fürbeth
Proceedings EUROCORR 2011
Magnesium alloy AZ31 was anodized in 3 M KOH solution at different voltages below
4 V. It was shown that with increasing voltage the growth rate of the resulting anodizing layer increases as well as the amount and width of cracks in the layer. Potentiodynamic polarization tests revealed an improved corrosion protection. Anodizing layers generated in alkaline dispersions of silica nanoparticles contained silicon in a homogeneous distribution, as shown by WDX based cross section images of the anodized samples. The amount of incorporated silicon rises when the electrical conductivity of the anodizing electrolyte is lowered by dilution.