Combining impedance and galvanostatic measurements for the study of oxide films formed on zirconium-based E-635 alloy under high-temperature oxidation conditions

Impedance measurements for oxide films on zirconium-based E-635 alloy that is used as cladding for fuel rods in nuclear reactors are conducted. The impedance data are shown to provide surface-averaged properties of the oxide films. A galvanostatic method applied for evaluating the alloy’s tendency to localized corrosion enabled us to determine the minimum thickness of the oxide layer, which depended on surface treatment used. The elemental composition of and residual stress at the surface are determined via microfluorescence spectroscopy and X-ray diffraction analysis.