Corrosion Behavior of AZ80 Magnesium Alloy in Simulated Static and Dynamic Fluid Environments with Different pH Values

Samples prepared with the AZ80 magnesium alloy were immersed in simulated body fluids (SBF) with different flow rates (0 and 3 mL/s) and different pH values (4, 7.4 and 9). During the immersion process, the electrochemical impedance spectrum (EIS) and the dynamic potential polarization curves were measured using an electrochemical work station. Scanning electron microscope (SEM) and energy spectrometer (EDS) were used to observe the corrosion morphology of the sample surface and the chemical composition of the corrosion products. The results showed that the corrosion resistance of samples increases with increasing pH values, and decreases with increasing flow rates. In the SBF with different pH values, the effect of the flow rate on the corrosion resistance of the magnesium alloy is different. The corrosion resistance of magnesium alloy was the least affected by the flow rate in pH4 environment, and the most affected in pH9 environment. The corrosion mechanism of magnesium alloy under the interaction of flow rate and pH value was discussed.