Study of the corrosion protection behavior of neutral water-based rust remover on carbon steel

The purpose of this work was to study the corrosion protection behavior of neutral water based rust remover on carbon steel. The reaction between rust remover and steel was explored by X-ray diffraction (XRD), FT-IR, energy dispersive spectrometer(EDS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy(XPS). Tests revealed that the surface of low-carbon steel treated with neutral rust remover was relatively smoother and the rust was capable of reacting with rust remover by forming a Fe-O-P and Fe-O-C chelate film. Besides, the rust-removing samples with a larger impedance value showed a better corrosion resistance than the rusty samples. Corrosion resistances of the film were investigated in sodium chloride solution of different concentrations by using Tafel polarization technique and electrochemical impedance spectroscopy. The results demonstrated that the film of carbon steel was highly susceptible to solution with chloride, which was characterized by the decreasing corrosion potential (Ecoor) of the samples and the increasing corrosion current density with the addition of chlorides. Meanwhile, the film formed during a 1-hour immersion time had a better corrosion resistance (a larger impedance value) than other samples, but other samples with different immersion times in the rust remover had no significant difference owing to the strong penetrating power of chloride ions.