Polarization measurements from a rotating disc electrode for characterization of magnesium corrosion

• The use of the rotating disc electrode (RDE) during polarization measurements is analyzed.
• The corrosion layer formed during polarization is reduced by the use of the RDE.
• Experimental results are in agreement with the enhanced catalytic surface theory.
• Polarization test reproducibility is improved when ω > 1500 rpm.
• The scan rate does not play an important role when RDE is applied.

Degradation of pure Mg is characterized by potentiodynamic polarization using a rotating disc electrode (RDE) where the Mg sample is placed. The rotation makes a fluid flow which removes dissolved Mg2+ from the Mg surface surrounding reducing the corrosion layer precipitation. This reduces the influence of corrosion products which accelerate the cathodic activity during anodic polarization. The results are in agreement with the enhanced catalytic surface theory. The use of the RDE gives highly reproducible results at higher rotation speeds than 1500 rpm and the scan rate does not have any influence on consecutive polarisations when higher than 5 mV/s.

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