Corrosion behavior of as-cast and hot rolled pure magnesium in simulated physiological media

Magnesium is a biodegradable metal that has significant potential advantages as an implant material. However, the fast degradation rate in the biological environment has limits the application. In this article, corrosion behaviors of as-cast and hot rolled pure magnesium in 0.9% NaCl, Ringer’s, and Tas-SBF solutions were studied. Potentiodynamic polarization and hydrogen evolution test were employed to assess the corrosion behaviors. The magnesium specimens were characterized using field emission scanning electron microscopy equipped with energy-dispersive X-ray analysis and X-ray diffraction. The as-cast specimens in 0.9% NaCl and Ringer’s solutions had lower corrosion potentials and corrosion rates than the hot rolled specimens. However, the as-cast specimen in the Tas-SBF solution had a higher corrosion potential and a lower corrosion rate than the hot rolled specimen. Only the specimens in the Tas-SBF solution showed passivation behavior due to the presence of HCO₃ ⁻ ions. The hot rolled specimen could form apatite more easily on its surface than the as-cast specimen in Tas-SBF.