Advanced Immersion Testing of Model Mg-Alloys for Biomedical Applications

The acceleration of developing magnesium alloys for biomedicine requires the advancement of experimental methods evaluating their performance. We have been developing an advanced immersion testing method for the assessment of biomedical Mg alloy degradation in aqueous environments. It is based on the combination of isothermal calorimetry with pressure measurement in the reaction cell. Such a combination allows in situ quantitative analysis of chemical reactions based on both the enthalpy (heat) of the process itself and hydrogen gas generated as one of the reaction products. Here, we analyze the evolution of the degradation rate of a ternary Mg-5.0Zn-0.3Ca intended for biomedical applications and two model binary Mg-5.0Zn and Mg-0.3Ca alloys (in as-cast and solutionized states) in 0.9% NaCl water solution and a simulated body fluid (SBF). The results obtained using the novel method are critically compared to more traditional immersion testing with hydrogen collection.