Zn-Sn deposits with the Zn content varying from 85 to 22 wt. % were pulse electroplated onto steel substrate from an acid sulphate plating bath. The corrosion behavior of Zn-Sn deposits including sacrificial property were determined in 5% NaCl solution by open-circuit potential measurement, potentiodynamic test, and electrochemical impedance spectroscopy (EIS). The open-circuit potential of Zn-Sn deposits are similar to that of a pure Zn, regardless the Zn amount in the deposit. This indicates that the initial corrosion behavior of Zn-Sn coating system is determined by the sacrificial properties of Zn due to the phase separation of Zn and Sn in the deposit.
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