Effects of Sr and Sn on microstructure and corrosion resistance of Mg–Zr–Ca magnesium alloy for biomedical applications

Highlights: ► Element alloying is one of the effective ways to modify the performance of alloys. ► Sr and Sn were simultaneously used to improve the corrosion resistance of Mg–Zr–Ca. ► Mg2Sn was mainly found within the grain interior. ► Corrosion resistance was improved obviously. -- Abstract: Magnesium based alloy is a biodegradable metal that has significant potential advantages as an implant material. Element alloying is one of the effective methods to modify the performance of the magnesium alloy. In the paper, Sr and Sn as alloy elements were simultaneously added into the Mg–Zr–Ca alloy to improve the corrosion resistance. The differences of Mg–Zr–Ca alloy and Mg–Zr–Ca–Sr–Sn alloy were compared. The X-ray diffractometer (XRD) and the scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) were used to analysis the phases and the microstructure of the alloys. The results indicated that the addition of Sn could form Mg2Sn mainly within the grain interior; Sr phase was mainly detected along the grain boundary. Immersion tests and electrochemical measurements showed that the corrosion resistance was improved obviously with simultaneous addition of Sr and Sn in Mg–Zr–Ca alloy. It suggested that bio-magnesium based alloy can use Sr and Sn as effective alloy elements to modify its performance.