Electrochemical behavior of magnesium alloys in simulated body fluids


Potentiodynamic electrochemical technique was utilized to study the corrosion behavior of magnesium alloys in simulated body fluids (SBFs). The influence of materials, solutions and their temperature on corrosion rate was mainly discussed. The results demonstrate that the free corrosion potential (Ecorr) of AZ31 and AZ91 alloys rises rapidly at initial stage, and then stabilizes at some value. Ecorr of WE43 alloy increases continuously. While Ecorr of AZ91 alloy with macro-arc oxidation (MAO) coating decreases drastically in 3 min, and then fluctuates between −1 607 mV and −1 503 mV. The WE43 alloy has better corrosion resistance in Hank’s solution, compared with AZ31 and AZ91 alloys. Corrosion rates of the alloys are sensitive to the chemical composition and temperature of SBFs. A thin MgF2 film slightly improves corrosion resistance. An MAO coating on AZ91 alloy significantly reduces corrosion rate and enhances Ecorr. Pitting corrosion occurs on both AZ31 and WE43 alloys in Hank’s solution.
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