Understanding Mg corrosion and biocorrosion

08.07.2019 von 16:00 bis 17:00

Andrej Atrens1, Sean Johnston2, Zhiming Shi1 , Matthew S. Dargusch2

1The University of Queensland, Materials Engineering Division, School of Mechanical & Mining Engineering, Brisbane, Qld 4072, Australia; 2The University of Queensland, Centre for Advanced Materials Processing and Manufacturing (AMPAM), Brisbane, Qld 4072, Australia


The first part of this talk reviews the main factors that control Mg corrosion immersed in aqueous solutions: (i) crystallographic orientation, (ii) impurity concentration (particularly Fe), and the influence of heat treatment, (iii) second phases, (iv) corrosion product films on the alpha-phase. Measurement effects are also mentioned.

The second part deals with Mg alloys for biodegradable medical implants. Over the last decade, Mg alloys have progressed from a laboratory concept to significant clinical successes. For this application, corrosion which is normally an unwanted feature of Mg alloys, becomes critical for success. It is vital to understand and control the corrosion rate. In vitro research has identified the following factors as the most important: (a) the inorganic ions like calcium, chlorides, bicarbonates, phosphates; and (b) the organic compounds including proteins, amino acids and vitamins. The best estimates for Mg corrosion rates (based on in vitro measurements) are larger than the corrosion rates measured in vivo. This suggests that the Mg corrosion mechanism in vivo is not adequately characterized, or the in vivo environment is not equivalent to immersion in a solution as used in the in vitro experiments. In fact, recent examination of specimens  implanted subcutaneously into Sprague-Dawley rats indicated that the in vivo environment was not at all equivalent to immersion in a solution, but rather the environment could be better described as damp.

Prepared as an invited presentation to Symposium F: Biomaterials

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