ABSTRACT
The corrosion resistance of pure magnesium (Mg) is relevant to the tolerance limits of impurities. When the impurity concentration exceeds the tolerance limit, the corrosion rate is greatly accelerated. The most harmful impurities to pure Mg are Fe, Cu, and Ni with tolerance limits of 170 ppm, 1000 ppm, and 5 ppm, respectively. Besides combining the impurity elements, alloying elements influence the corrosion resistance of Mg alloy in several ways. The active nature of Mg means that galvanic effect is always an issue. As Mg is more active than most other engineering alloys, consequently, Mg is the anode and corrodes preferentially in any galvanic. Mg alloys always suffer from nonuniform corrosion due to the existence of internal galvanic coupling or electrochemical nonuniformity. The corrosion fatigue behavior of Mg alloys examined by the standard metallic biomaterial testing method in a physiological environment was studied.
