EIS investigation of passive film formation on mild steel in oxalic acid solution
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The properties of oxide films on mild steel formed anodically in aqueous solution containing oxalic acid were investigated by means of electrochemical impedance spectroscopy (EIS). The morphology of the passive layers at different stages of film formation was investigated using scanning electron microscopy (SEM). Passivation of mild steel in oxalic acid solution is a multi-stage process that occurs before passive layer breakdown. The influence of potential on the electrochemical behavior of the passive layer was also investigated. Depending on the passive layer potential, the EIS spectra obtained exhibited a one- or two-time constant system. This suggests the formation of either a one layer or two layer oxide film on the mild steel surface, depending on the passivation potential.
KeywordsElectrochemical impedance spectroscopy Oxalic acid Passive layer
The authors thank the Vice Chancellor for Research and Center of Graduate Studies, Isfahan University of Technology for financial support. Editing of the manuscript by Mrs Chris Abachi and Mr Gaetano Giglione is greatly appreciated.
- 6.Ashrafi A, Golozar MA, Mallakpour S (2003) Iran Polym J 12:485Google Scholar