红壤中变电站接地网金属材料的腐蚀行为分析

Macroscopic analysis and corrosion product analysis of galvanized flat steel which had been in service for 13 a in substation grounding grid were made by scanning electron microscopy (SEM), energy spectrum (EDS) and X-ray diffraction (XRD). The result shows that galvanized flat steel suffered serious corrosion and corrosion products are mainly composed of FeOOH, Fe3O4, Fe2O3 and etc. The cause of the corrosion product layer is the new production of corrosion products deposition on the metal/corrosion product layer interface or the cracking. At the same time, S and Cl have great influence on the inner corrosion products. Tafel test results show that the percentage of SO42- and Cl- is 12 and they have equivalent effect on the corrosion influence of galvanized Q235 carbon steel near the corrosion current peak. Result of the accelerated corrosion experiment shows that corrosion rate of galvanized Q235 carbon steel in red soil increase first and then decrease meanwhilethe corrosion mechanism of galvanized Q235 carbon steel in this acceleration that had a good speedup was unchanged.