Evaluation of cavitation erosion-corrosion degradation of mild steel by means of dynamic impedance spectroscopy in galvanostatic mode

摘要

Cavitation erosion and corrosion of mild steel was studied by means of a vibratory facility in 3% w/w NaCl solution. Dynamic Electrochemical Impedance Spectroscopy (DEIS) measurements were carried out in the galvanostatic mode to allow on-line monitoring of impedance parameters in cavitation failure. The results, based on an analysis of instantaneous impedance spectra, correspond to degradation under the influence of cavitation erosion-corrosion. It has been shown that a change of pseudo-capacitance corresponds to an increase in sample roughness, while the charge-transfer resistance determines changes in the corrosion rate under the combined mechanical and electrochemical factors.