Effect of Mn Addition on Corrosion and Biocompatibility Characteristics of a New Biodegradable Mg–1Ca–2Zn–1RE Alloy

In this study, the effect of Mn addition on the corrosion properties and biocompatibility of a new biodegradable Mg–1Ca–2Zn–1RE–xMn alloy (x = 0, 0.3, 0.6, 0.9 wt%) was investigated using Hank’s solution. The main purpose was to achieve a biocompatible alloy with optimum corrosion properties which can be used to fabricate biodegradable implants. Thus a special composition of alloying elements was used. X-ray diffraction analysis revealed that Mn addition does not induce any Mn intermetallic phase. Besides, Mn shifted the solute elements from the grain boundaries toward the matrix. The corrosion resistance of the alloys was efficiently improved by adding Mn, according to the electrochemical measurements. The highest corrosion resistance in comparison with other alloys was observed for the alloy with 0.9 wt% Mn. Moreover, the Fourier-transform infrared spectroscopy test and scanning electron microscope images of the immersed specimens in Hank’s solution, indicate that Mg–1Ca–2Zn–1RE–xMn is a biocompatible alloy as phosphate and carbonate groups are formed on the specimens which are the fingerprint of hydroxyapatite formation. Graphic Abstract