Research On Corrosion Behavior Of Stainless Steel In Marine Atmospheric

Stainless steel materials have excellent corrosion resistance in general atmospheric environments,but they are prone to corrosion in marine and atmospheric environments.Nowadays,a large number of stainless steel materials are used in the engineering construction process.Through corrosion investigations,it is found that stainless steel is constructed in coastal marine atmospheric environments.The corrosion phenomenon is serious,and there is no obvious corrosion of stainless steel in the atmospheric environment of inland cities.Therefore,in order to better select stainless steel materials,it is urgent to carry out research on the corrosion behavior of stainless steel materials in the marine atmosphere.In this dissertation,6 kinds of stainless steel materials are selected,including different surface(2B and BA)conditions,and atmospheric corrosion tests are carried out at Wenchang,Qingdao,and Wuhan test stations.Through macroscopic and microscopic morphology analysis,electrochemical testing,XPS,XRD detection and analysis of surface passivation film composition combined with molecular dynamics simulation test,the corrosion behavior of stainless steel materials in the marine atmosphere is studied;multi-concentration corrosive ion electrolysis is studied Electrochemical corrosion behavior of liquid on stainless steel.The main research results are as follows:(1)The corrosion behavior of stainless steel materials in different atmospheric exposure stations is significantly different.The corrosion behavior of samp les at the Wenchang station is the most serious,followed by the Qingdao station,and the Wuhan station has the lightest corrosion.And in the same exposure station,there are also differences in the degree of corrosion of stainless steel materials.In Wen chang station,316(2B)stainless steel has the least corrosion degree,and 430(2B)stainless steel has the heaviest corrosion degree;in Qingdao station,439(2B)stainless steel has the least corrosion degree and 430(2B)stainless steel has the heaviest co rrosion degree.There are basically no corrosion products on the surface of the samples in Wuhan station,and none of the materials have obvious corrosion.In the same exposure station,comparing 304(2B)and 304(BA)surface stainless steels,the corrosion degree of 304(BA)is significantly less than that of 304(2B),indicating that the corrosion resistance of stainless steel materials has been improved after BA surface treatment.(2)The electrochemical experiment results of the rusted samples are basically consistent with the morphology analysis results.Among them,the corrosion rate of rusty316(2B)stainless steel in Wenchang station is the smallest;in Qingdao station,the corrosion rate of rusty 439(2B)stainless steel is the smallest;in Wuhan station,t he corrosion rate of 316(2B)stainless steel is the smallest.Comprehensive analysis of the performance of the samples after exposure is recommended.The stainless steel material used in Wenchang area should be 316(2B)stainless steel,and the bright surfa ce treatment should be carried out to obtain BA surface to improve corrosion resistance;Qingdao area can use 439(2B)stainless steel material Substitute 316(2B)stainless steel to reduce costs;6 kinds of stainless steel materials in Wuhan performed well.(3)The electrochemical experiment results of corrosive ion solutions with different concentrations show that the changes of Cl^-and HSO3^-concentration seriously affect the corrosion rate of stainless steel materials,and the impact of Cl^-is higher;comparing single corrosion solution and mixed corrosion solution,it is found that Cl^-,HSO3^-has a synergistic effect that will accelerate the corrosion of stainless steel.(4)Based on the XPS and XRD test results of passive films,the main component of the passive film is Fe2O3,Cr2O3,Mn O2,MoO₃,MoO₂,Fe O,etc.;the results of molecular dynamics simulation experiments show that the surface of stainless steel is passivated.The Cr2O3 in the film inhibits the diffusion of Cl^-,MoO₃ and MoO₂ inhibit the diffusion of HSO3^-.