From Microstructural Changes to Electrochemical Behavior: Decoding the Corrosion Mechanism in Zr-Sn-Nb-Fe-Cr-Mo-O-V Alloys

The oxide formed on a Zr-0.4Sn-0.7Nb-0.3Fe-0.1Cr-0.15Mo-0.12O-0.05V, wt. % alloy, after exposure for 300 d in 360 °C/20 MPa (water with 0 ppb, 300 ppb, and 1000 ppb), was characterized by transmission electron microscope (TEM), precession electron diffraction (PED) and electrochemical impedance spectroscopy (EIS). Results showed that DO accelerated the corrosion of the alloy, and this effect was enhanced with the increase of the DO concentrations. A mechanism of the correlation between electrochemical behavior evolution and microstructural changes of oxide film was proposed, which provided theoretical guidance for the selection of fuel cladding materials for small nuclear reactors.