Evaluation of corrosion Behavior of Commercially Pure Magnesium and Magnesium-Calcium Alloy as Biodegradable Magnesium Implant Materials in Physiological Solutions

Magnesium is a metal with high biocompatibility and a necessary material for human body metabolism that because its desirable mechanical properties compared with Biodegradable polymers, has been studied at recent years for production of biodegradable materials at human body. In this study, calcium containing magnesium alloy and commercial pure magnesium was casting in the same terms and their chemical composition and phases was reconnoitered by Quantometer device, XRD analysis and optical microscopy. Then corrosion behavior of these materials was investigated by tafel polarization technique in two simulated body fluid solutions (SBF and Hank solutions) and the surface morphology of materials was studied with scanning electron microscopy. This research showed that adding calcium to magnesium as an alloying element increase the formation of calcium-magnesium phosphate layer but due to formation of microscopic galvanic cells between magnesium atoms (cathode) and calcium atoms and Mg2Ca intermetallic phase (anode), the corrosion rate of alloy will be increased. Also observed that corrosion behavior of calcium containing magnesium alloys largely depended on dispersion mode of Mg2Ca intermetallic phase.