Glass-forming ability and corrosion performance of Mn-doped Mg–Zn–Ca amorphous alloys for biomedical applications

In the present work, ribbon and 2-mm rod samples of Mg–Zn–Ca–Mn alloys were prepared by melt-spinning and copper mold injection methods, respectively. Effects of Mn doping on glass-forming ability and corrosion performance in simulated body fluid of Mg₆₅Zn₃₀Ca₅ alloy were studied through X-ray diffraction, scanning electron microscopy, differential scanning calorimeter, and electrochemical and immersion tests. Results show that with the Mn addition increasing, all the ribbon samples are completely in amorphous state. However, the microstructure of 2-mm rod samples transfers from fully amorphous for the Mn-free alloy to almost polycrystalline state with precipitated Mg, Mn, and MgZn phases. Glass-forming ability of Mg₆₅Zn₃₀Ca₅ alloy is decreased by Mn addition. Results of electrochemical and immersion tests demonstrate that the Mn-doped samples exhibit more negative corrosion potential and larger corrosion current density, suggesting that the corrosion resistance decreases with doping amount of Mn element increasing.