In vitro study of Biodegradation in Mg-alloys by Isothermal Calorimetry

Sammanfattning: Magnesium corrosion in an aqueous environment is a multi-layer, complex process. A literature survey shows significant gaps and the modelling work reported indicates a lack of clarity in understanding the corrosion process. Studies on the effects of impurities and interfacial compounds formed by selected alloying additions would help in filling some of these gaps. Further, the evolution of hydrogen gas with the dissolution of magnesium may pose a threat to living cells in Biomedical Applications. As a result, it is critical to monitor Mg corrosion rates and investigate the impact of alloying elements. For clarity, an overview of the basic mechanisms of magnesium corrosion in an aqueous solution and the thermodynamic background is presented. The project investigates the corrosion behaviour of three alloys (Mg-0.8Nd, Mg-0.2Zr & Mg-0.8Nd-0.2Zr) in a 0.9wt% NaCl solution using Isothermal calorimetry and the pressure measurement technique. Heat flow, and energy changes were monitored, providing the basis for understanding the corrosion process. Hydrogen gas evolution measurements were correlated with thermal power. Small changes in the corrosion process lead to noise-like variations in thermal power. The effect of alloying addition and heat treatment on corrosion rates have also been addressed in the present study.