A study on corrosion resistance of Al magnetron sputtering coated AZ31 magnesium alloy

In this study, Al magnetron sputtering was used to enhance the corrosion resistance of AZ31 Mg alloy. Samples were cut and prepared with no treatment, ground up to #600 and ground up to #5000 abrasive paper. Then samples were coated at temperatures of 400 °C, 350 °C and 25 °C. Then, samples were heat treated in an argon atmosphere at temperatures of 500 °C and 400 °C. OCP, impedance and Tafel tests were applied on the samples. The sputtered sample with no surface treatment showed an impedance of 28.51 Ω.cm2 and corrosion current density of 1250 μA.cm-2 in comparison to the non-coated sample with an impedance of 40.66 Ω.cm2 and current density of 78.5 μA.cm-2. The sample ground up to #5000 abrasive paper showed an impedance of 1000 Ω.cm2 and current density of 16.9 μA.cm-2. Impedance of this sample was approximately 20 times higher than others.