Corrosion Rates by Immersion and Calorimetry on the Example of Extruded Mg10Gd(1Nd)1La

This study is a follow-up investigation of the influence of the alloying elements Nd and La on the corrosion by immersion of an extruded and heat-treated Mg10Gd. The previous study made clear that the age-hardened condition has the lowest corrosion rate but high pitting corrosion susceptibility. The extruded Mg10Gd(1Nd)1La shows the lowest pitting factors based on severe corrosion. In this study, the corrosion morphology and corrosion rates are discussed based on calorimetric data and 3D-analysis by µCT and compared to the results from the immersion tests. Thermal power and enthalpy readings from the isothermal calorimetry offer information on the reaction kinetics. The corrosion rate values are discussed based on the evaluation method—in general agreement alloying with Nd reduces the corrosion rate. The pitting factor is found to be very dependent on the reference average penetration: weight or volume loss, or evaluation by 3D volume or by 2D cross-sections.