Influence of hydrogel coatings on corrosion and fatigue of iron in simulated body fluid

Surface corrosion and fatigue studies of pure iron were performed in a modified simulated body fluid (m-SBF) electrolyte with and without applied agar films as a typical hydrogel film. The electrochemical corrosion rates were analysed using electrochemical impedance spectroscopy. The morphology and surface chemical composition of the samples after exposure were analysed using X-ray photoelectron spectroscopy and Raman microscopy. The swelling process of the agar film was measured by in situ fourier-transform infrared spectroscopy in attenuated total reflection. The combination of the electrochemical and interface analytical approaches allowed for the estimation of the influence of an applied agar film on the corrosion processes. Moreover, the studies clearly reveal a correlation between the surface corrosion process and the fatigue life of the iron samples in m-SBF.