Corrosion behaviors in physiological solution of cerium conversion coatings on AZ31 magnesium alloy

In this paper, a non-toxic Ce-based conversion coating was obtained on the surface of bio-medical AZ31 magnesium alloys. The micro-morphology of the coating prepared with optimal technical parameters and immersed in physiological solution (Hankʹs solution) in different time was observed by scanning electron microscopy (SEM), composition of the cerium conversion coating and corrosion products in Hankʹs solution were characterized by X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS), respectively. In addition, the corrosion property in Hankʹs solution was studied by electrochemical experiment and immersion test. The results show that the dense Ce-based conversion coating is obtained on the surface of AZ31 magnesium alloys in optimal technical parameters and the conversion coating consists of a mass of trivalent and tetravalent cerium oxides. The cerium conversion coating can provide obvious protection of magnesium alloys and can effectively reduce the degradation speed in Hankʹs solution. Also the degradation products have little influence on human body.