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.