Influence of temperature on electrochemical behavior and oxide film property of Alloy 800 in hydrogenated high temperature water

Abstract

The effects of temperature on the electrochemical behavior and oxide film property of Alloy 800 in hydrogenated high temperature water are studied using potentiodynamic polarization curves, electrochemical impedance spectra (EIS), scanning electron microscopy (SEM), and X‐ray photoelectron spectroscopy (XPS). The corrosion resistance of Alloy 800 passes through a local minimum at 250 °C. The kinetic controlling step of the growth of oxide films at 200–300 °C changes from the diffusion of ions in aqueous phase to the growth of Cr‐rich barrier layer. A modified model is proposed to explain the effect of temperature on the property of the oxide films on Alloy 800 in hydrogenated high temperature water.