Comparative Studies on Degradation Behavior of Pure Zinc in Various Simulated Body Fluids

The initial corrosion behavior of pure zinc during 168h of immersion in Hanks' solution, simulated body fluid (SBF), Dulbecco's modified Eagles' medium (DMEM), and DMEM with 10% fetal bovine serum (FBS) was investigated. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were performed on samples after immersion. The morphology and chemical composition of corrosion products were determined by environment scanning electron microscope, x-ray diffraction, x-ray photoelectron spectroscopy, and Fourier transform infrared spectrometer. The results demonstrated that pure Zn degraded at a rate of 0.01mmyr(-1) to 0.02mmyr(-1) in DMEM and DMEM+FBS and exhibited the highest corrosion rate in SBF. It was shown that the composition of solution was crucial for the evaluation of degradation behavior in vitro. Insoluble salts formation and organic components in DMEM retarded the degradation of Zn. The presence of proteins increased the polarization resistance while it also exacerbated localized corrosion.