Influence of chloride ions on corrosion behaviour of zinc-alloy in the simulated body fluid solution

The bio-corrosion behaviours of the Zn alloy in the simulated body fluid (SBF) at different chloride ion concentrations were investigated. The Potentiodynamic Polarisation Curve (PDP) and Electrochemical Impedance Spectroscopy (EIS) results indicate that the corrosion rate of Zn alloy decreases with higher chloride ion concentrations. The decrease in corrosion rate is due to the formation of a protective layer of ZnCl2 nanofibres and agglomerates. The surface morphology and analytical studies of the Zn alloy were carried out by scanning electron microscopy (SEM), EDX, atomic force microscopy (AFM), and X-ray diffractometry. The SEM, EDX, and X-ray diffraction studies indicate the formation of nanofibres and agglomerates of ZnCl2. The AFM measurements show the increase in surface roughness due to the in situ formation of nanofibres and agglomerates on the alloy surface. Therefore, these results are useful to tailor the design of Zn alloy-based biomedical materials being implanted for the living body.