Synthesis of oxide-ceramic coatings on magnesium alloys and their corrosion properties

If a voltage of several hundred volts is applied to a metal-electrolyte system, electric discharges occur which result in a plasma developing in the discharge channels and in an oxide deposition on the metal surface. In the present study the number density and temperature of the plasma electrons and the optimum current conditions and electrolyte composition for obtaining oxide-ceramic coatings on magnesium having a thickness of 20 - 140 mum and a microhardness of 10 GPa were determined. The corrosion resistance of three magnesium alloys was investigated in 0.3% HCl (pH 3.1) and 0.3% NaCl solutions (pH 6.3) using polarisation experiments.