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. (C) 2014 Elsevier B.V. All rights reserved.