Effects of Mg₁₇Sr₂ Phase on the Bio‐Corrosion Behavior of Mg–Zr–Sr Alloys

The effect of the second phase Mg₁₇Sr₂ on the biocorrosion behavior of Mg5ZrxSr (x = 0, 2, 5 wt%) alloys before and after solution treatment was investigated. Electrochemical impedance spectroscopy, cathodic polarization and hydrogen evolution were used to evaluate the biocorrosion of Mg5ZrxSr. We found that Mg₁₇Sr₂ precipitated on boundary zones and enhanced the galvanic effect, leading to a severer corrosion of the Mg matrix adjacent to Mg₁₇Sr₂. The corrosion subsequently spread gradually from the regions adjacent to the Mg₁₇Sr₂ to the central Mg matrix. However, a high volume fraction of Mg₁₇Sr₂ could also form a continuous network, isolate the Mg matrix and act as a barrier of corrosion.