Effects of hydrogen on the corrosion of pure magnesium

Electrochemical measurements and capacitance measurements were performed for better understanding of the effects of hydrogen on the corrosion of pure magnesium. Anodic polarization curves, activation energy (Ea), pitting initiation time and electrochemical noise (EN) were carried out, which showed that hydrogen had a strong influence on the corrosion of magnesium. There existed a highest corrosion resistance of magnesium, when a series of cathodic charging current density were applied to the specimens due to the optimum hydrogen concentration in the hydride coating (MgH2) on the surface. Mott–Schottky results confirmed that there was a hydride coating on the charged magnesium. Hydrogen ionized as H− and depleted donor/electron, which induced the inversion of semi-conductivity from N-type to P-type.