Comparative study on corrosion behaviour of pure Mg and WE43 alloy in static, stirring and flowing Hank's solution

WE43 magnesium alloy has been considered as a promising candidate material for biodegradable coronary stents. In order to evaluate the effects of blood flow on the corrosion process of biodegradable Mg and its alloys, the corrosion behaviours of as cast pure Mg and as extruded WE43 alloy in Hank's solution under three different conditions, i.e. static, stirring and flowing, were investigated in the present work. We found that the as cast pure Mg exhibited much higher corrosion rate than the as extruded WE43 alloy regardless of the liquid flowing condition of the solution. Both pure Mg and WE43 alloy samples exhibited the lowest corrosion rate under the stirring condition while the flowing condition promoted local corrosion with the corrosion rates three to six times faster. The results of this study suggest that static immersion may be not proper to predict in vivo corrosion rates of magnesium alloy stents.