Effect of Gd element on corrosion rate of SLM forming medical magnesium alloy

Abstract:

Magnesium alloy is an ideal bone implant material with high specific strength and good biocompatibility.SDue to the limitation of rapid degradation rate of magnesium alloy in clinical application, SLM can be used to alloyed magnesium alloy and improve its corrosion resistance.SMg-1zn-xGd (x=0, 0.25, 0.5, 1, 2 wt%) alloy was formed by SLM, and the average corrosion rate of magnesium alloy soaked in simulated body fluid for 72 h was tested. The corrosion mechanism was analyzed by SEM, EDS and TEM.SThe experimental results show that Gd content has a significant effect on the corrosion rate of magnesium alloy, and the degradation rate of magnesium alloy decreases first and then increases with the addition of 0~2 wt% Gd, and the magnesium alloy has the best corrosion resistance with the addition of 0.5 wt% Gd.SThe surface passivation film produced by the corrosion reaction can slow down the corrosion process to a certain extent, and the Mg₅Gd phase precipitated along the grain boundary increases after the addition of excessive Gd, resulting in intensified corrosion of magnesium alloy.