Electrochemical Impedance Spectroscopy: Insights for fretting corrosion experiments

Using Electrochemical Impedance Spectroscopy (EIS), in the tribocorrosion field, especially in fretting corrosion, is new. The key point of this work is using EIS. The influence of ionic strength (Ic) and a model protein, albumin, on passive layer behavior was studied. At cathodic applied potential, E=−400 mV(SCE), fretting leads to an increase of corrosion current, without albumin. The current drop increases with the ionic strength. With albumin of 20 g L−1, I is constant whatever the ionic strength: albumin acts as a corrosion inhibitor. Thanks to EIS, the degradation of passive layer due to fretting-corrosion is assessed by the fall of Polarization Resistance (Rp) and exponent of constant phase element (n), and the rise of constant phase element (Q).