Electrochemical characteristic analysis of corrosion of coated steel bars in magnesium oxychloride concrete

Abstract

In view of the service life of structural buildings of reinforced magnesium oxychloride concrete in western saline soil and the corrosion of chlorine ion content of magnesium oxychloride cement on steel bars, coatings are used to alleviate the degree of corrosion in different environments. The open-circuit potential, polarization resistance and corrosion current density of coated and bare steel bars in different environments were analyzed using a Z350 electrochemical workstation. The products were also analyzed by scanning electron microscopy and X-ray diffraction microtests. The tests showed that an zincite (XMT) coating can protect steel bars from corrosion under different environments. The corrosion current densities of coated steel in sulfate, chloride and water were 5·26, 2·33 and 2·86% of that of bare steel. The average value of the polarization resistance of the coated steel bars was about five times that of the bare steel bars. There were loose porous layers and massive corrosion on the bare steel surface, while the surface of the coated steel had only pitting corrosion. Therefore, the anticorrosion effect of the XMT coating on steel bars in magnesium oxychloride concrete was obtained, so that concrete with magnesium oxychloride-coated reinforcement has better application prospects in saline soil.