Study On The Carbon Steel Corrosion At Tropic Seashore Atmosphere

The corrosion problem spreads all over the each realm of national economy developments, a flood of components, facilities and establishments invalidation because of corrosion bring about enormous economy Loss for the nation Atmospheric corrosion of metals is the most widespread and serious among all of corrosion The 50% economy loss resulting in various corrosion is accounted for invited metals atmospheric corrosion It has very important theory meaning and extensive application value for reasonable choice of materials and homologous protection measures, control of corrosion rate in the atmosphere, extension of the service life of the equipments and material, reduction of economy loss resulting from corrosion, and so on.The author adopts that the steels of Q235 is exposed at Wanning site located in Hainan province of China. The corrosion products were analyzed with ESEM, XRD and XPS. Temperature, humidity and concentration of Cl^- in test district were continuously examined, analyzed and researched.The researches indicate that the effects of hot and humid marine environment on steel at atmospheric corrosion were complicated process. The sample's corrosion depth on the ocean platform was much lower with 25 meters and 95 meters at the early decay, but after one year atmosphere exposure the corrosion rate of the samples located at 25 meters and 95meters slowed down, and the ocean platform sample had been accelerate ascension The ocean platform sample decays the depth data to match the function regulation (D=Atⁿ), the fitting result as y=0.3365x^1.8719 (R²=0.9947), the n value be up to 1.87.The ESEM result showed that different corrosion morphology of the outside level rust layers, and a great lot of several hundred nanometers grain form corrosion product, such as slice form, the needle form and the pillar form etc. Study the dynamics behavior through the rust layer micro-morphology, the needle form and the pillar form's decaying an outcome to heading up or getting down a growth will increase the whole internal help dint of rust layer, making the between levels be apart from aggrandizement, the rust layer the crack and blind side enlarge, making corrosive medium to invade more easily, causing the rust layer inner part and the body decay acceleration. But slice form corrosion product decay an outcome of growth then toward different direction, at the rust layer the inner part is output of should the dint is small, of the slice and slice folds to add and covers up mutually, corrosive medium irruptive the internal body is opposite more difficult, have to the body certain protection function.