Effect of Sr on the microstructure and biodegradable behavior of Mg–Zn–Ca-Mn alloys for implant application

In this paper, the effect of Sr on the microstructure and bio-corrosion behavior of Mg65.2−xZn30Ca4Mn0.8Srx (x = 0, 0.3, 0.5 and 0.8) amorphous matrix composite were investigated by X-ray diffraction, differential scanning calorimetry, scanning electron microscope, electrochemical measurements, immersion test and in vitro cytotoxicity test, respectively. Compared to the Mg–Zn–Ca-Mn alloy, the Sr-bearing alloys with minor Sr incorporation improved the glass formation ability and bio-corrosion resistance significantly. The corrosion products of the Mg65.2−xZn30Ca4Mn0.8Srx (x = 0, 0.3, 0.5 and 0.8) alloys mainly contained Zn(OH)2, hydroxyapatite and phosphate after 124 h static immersion test, which were beneficial to the bone growth. The results suggested that the novel Mg64.7Zn30Ca4Mn0.8Sr0.5 alloy possessed a good corrosion resistance and biocompatibility, showing a promising candidate for the biodegradable implants.