Effect of Ga content on corrosion behavior of Mg–Zn-Ga alloys in Hank's solution

Mg–Zn-Ga alloys have been studied as potential biodegradable materials with excellent mechanical properties. However, its corrosion behavior under physiological conditions remains a subject of investigation for future applications. In this study, the corrosion behavior of extruded Mg–2Zn-xGa (x ​= ​1, 3, 5 and 7 ​wt%) in Hank's solution was investigated. The corrosion products formed on the alloy surfaces were characterized by X-ray diffraction spectroscopy (XRD), scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FT-IR). The corrosion products layer was found to consist of two distinct layers based on composition. The inner layer contained Mg(OH)2 and carbonate, while the outer layer was composed of amorphous phosphate with Ca and Mg. The corrosion products layer exhibited a porous structure and was prone to detachment, particularly in regions undergoing non-uniform corrosion. Non-uniform corrosion behavior, attributed to micro-galvanic corrosion, was observed during the immersion of Mg–2Zn-xGa alloys. With an increase in Ga content, the increased amount of Mg5Ga2 phase intensify the non-uniform corrosion, resulting in an increased corrosion rate.