Research On The Metal Corrosion Mechanism Of Power Transmission And Transformation Facilities In Highly Corrosive Environmen

Atmospheric corrosion is the most common type of corrosion,and the economic losses caused by atmospheric corrosion account for more than half of the corrosion each year.The most important factor affecting atmospheric corrosion,in addition to climatic factors is the pollutant ions,of which the most serious impact is Cl^-and SO₂,corresponding to the marine atmosphere and industrial atmospheric environment,respectively.In the coastal industrial atmosphere,Cl^-and SO₂on the synergistic corrosion of metals is more serious.In this paper,Q235 steel and galvanized steel were selected to study the corrosion pattern of Q235 steel and galvanized steel in the coastal industrial atmospheric environment by using alternating wet and dry corrosion methods under different concentrations of Cl^-and NaHSO₃.Calculate the average corrosion rate and kinetic trend of metals by corrosion weight gain,analyze the composition of corrosion products by X-ray diffraction spectroscopy or infrared absorption spectroscopy,observe the microscopic morphology of corrosion rust layer on the surface of samples by scanning electron microscopy,the nature of atmospheric corrosion is electrochemical corrosion,analyze the process of electrochemical corrosion and the mechanism of electrochemical corrosion by electrochemical testing.Explore the influence of different pollutant ion concentrations on the corrosion pattern of metals.The corrosion rate of metal was calculated and the corrosion grade of metal was determined by hanging plate experiments in some areas of Guizhou Province,as well as the correlation between indoor and outdoor corrosion.The results show that the larger the Cl^-concentration,the more serious the synergistic corrosion of Cl^-and NaHSO₃on the metal.In the early stage of corrosion,the corrosion rate of Q235 steel is larger,the corrosion products have moreγ-Fe OOH and lessα-Fe OOH,and the microscopic morphology of corrosion products is mainly flaky and loose;the corrosion rate of galvanized steel is smaller,and the corrosion products are mainly Zn O,Zn₅（OH）₈Cl₂,etc.In the late stage of corrosion,Q235 steel corrosion rust layer becomes dense,protecting the substrate,the corrosion rate decreases;zinc layer of galvanized steel is destroyed,the substrate carbon steel began to corrode,the corrosion rate increases.Outdoor hanging sheet experiments in the chemical plant near the substation corrosion degree is serious.