Study of the corrosion behavior and the corrosion films formed on the surfaces of Mg–xSn alloys in 3.5wt.% NaCl solution

The corrosion behavior and the corrosion films formed on the surfaces of Mg–xSn (x = 0.5, 1.0, 1.5, and 2.0 wt.%) alloys in 3.5 wt.% NaCl solution were investigated by immersion tests, electrochemical measurements, corrosion morphology observations, and X-ray diffraction analysis. Immersion tests and electrochemical measurements illustrated that the best corrosion resistance was reported for the Mg–1.5Sn alloy. Both Mg(OH)2/SnO2 corrosion product film and Mg(OH)2/MgSnO3 clusters formed on Mg–1.5Sn alloy surface. Mg(OH)2/MgSnO3 clusters were compact and suppressed the cathodic effect of the impurity inclusions greatly. The Mg–xSn (x = 0.5, 1.0, and 2.0 wt.%) alloys only formed loose Mg(OH)2/SnO2 corrosion product film during the corrosion process.