Electrochemical Properties of Boiler Water-wall Tube 20G in Cl^- and SO2-₄ Media

In order to investigate the corrosion behavior of water-wall tube material 20G in equilibrium phosphate treatment (EPT) solutions containing Cl- and SO42- ions, a series of electrochemical experiments were carried out to analyze the room-temperature electrochemical properties of 20G in simulated EPT solutions. The electrochemical parameters of corrosion potential (Ecorr), corrosion current density (Jcorr) and AC impedance (Rp) were used to compare the corrosion resistances of the material. The results show that, at room temperature, Cl- and SO42- ions are aggressive anions attacking 20G electrode material and promoting its dissolution. Increasing the concentrations of the two ions can accelerate the corrosion of the material. There is competitive adsorption between the two ions on the material surface when they both exist in the solution.