In vitro and in vivo studies on two-step alkali-fluoride treated Mg-Zn-Y-Nd alloy for vascular stent application: Enhancement in corrosion resistance and biocompatibility

Bioabsorbable magnesium alloys are becoming prominent materials for cardiovascular stents, as their desirable mechanical properties and favorable biosafety. However, the rapid corrosion of magnesium alloys under physiological conditions hinders their wider application as medical implant materials. Fluoride chemical conversion treatment is an effective and simple technique to improve the corrosion resistance for magnesium alloys. Despite previous literatures report on fluoride chemical conversion treatment with hydrofluoric acid (HF) in different conditions, some defects are still present on the surface of the coating. In this study, we report on a two-step alkali-fluoride treatment of magnesium alloy by effectively removing the second phase in the substrate surface and form a dense and flawless magnesium fluoride (MgF2) coating to endow the magnesium alloy greater corrosion resistance. The results showed that the serious pitting corrosion caused by galvanic corrosion could be effectively prevented after re...