Abstract and subjects
Electrochemical impedance spectroscopy (EIS) is a powerful technique for the non-destructive, dynamic measurement of electrochemical corrosion behavior in condensed environments, and is a demonstrated, in situ method for monitoring oxide films formed on metal surfaces in liquid metals. To characterize this capability, the impedance properties of three kinds of oxide films (anodic titanium oxide films, deposited Fe2O3 films, and thermally oxidized Fe samples) in liquid metals were examined using the EIS technique. The results show that the impedance response is related to the oxide film thickness and quality. The impedance of thin oxide films (< 50 nm thick) in liquid lead-bismuth eutectic (LBE) is negligible, while the EIS of thicker oxide films (> 200 nm) shows that the oxide film without cracks is stable in LBE and protects the substrate from corrosion. EIS is a promising method for accessing the electrochemical behavior of oxide films on metals and alloys in liquid metals.