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Study On Arc Spraying Cored Wire Of Chlorine Corrosion Resistant

Posted on:2012-08-03Degree:MasterType:Thesis
Country:ChinaCandidate:R WangFull Text:PDF
GTID:2131330338991471Subject:Materials Science and Engineering
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In recent years, incineration has been adopted an effective and hygienic method for disposal of ever- increasing voluminous industrial and municipal solid waste in many countries including China. Some high calorific value section of it while utilizing waste as much as possible, generates heat, electricity and so on. In most cases, the corrosion problems in incineration environment are rather severe due to the complex reactions between the combustion gases containing chlorine or sulfur and salt deposits of chlorides and sulfates, in these environments metallic materials usually undergo an aggressive corrosion and degrade completely before the end of the designed life. In the article a new kind of high temperature chlorine corrosion resistance coating was prepared with wire spray technique to resolve the problem of waste incineration in high temperature circulating fluidized bed chlorine corrosion.The experiment shows that the coating has excellent high temperature chlorine corrosion and high temperature oxidation resistance, which can be used in high temperature circulating fluidized bed boiler water wall corrosion, with a very broad application prospects. Microstructure and conventional performance of coatings was analyzed by using SEM, XRD and other means of testing. And corrosion-resistant coating mechanism was studied. The main results are as follows:1. Investigated the best overall performance E3 cored wire by using stainless steel-strip to wrap metal powder of Ni, Cr, Al, Mo and rare earth elements. The E3 coating's oxidation resistance is 0.74 times for the PS45,and corrosion resistance is 0.67 times for the PS45,which has excellent corrosion resistance. The coating structure uniform and dense and the hardness close to the PS45, about 481HV0.1, and the coating porosity lower, and the bonding strength more than 35 MPa, which has a comprehensive excellent performance.2. Cored wire in the Cr content increases as the oxidation resistance of the coating can be gradually increased the antioxidant properties of Cr element better than Ni element. Ni's more excellent corrosion resistance compared Cr in the chlorine corrosive environment, Ni and Cr ratio of the appropriate elements of good overall performance.3. Cored wire element in the increase of Mo did not promote the role of oxidation resistance, instead which reduces the oxidation resistance of the coating. Amount of Mo content play a promoting role on the resistance to chloride corrosion, with Mo content increases, the coating resistance to chloride corrosion is also increasing in the salt spray corrosion environment.4. Rare earth element can improve the corrosion resistance of the coating, amount of rare earth addition on the corrosion resistance coating has increased significantly, but the rare earth elements to be compatible with other alloying elements can play a better corrosion resistance effect.5. Analysis high-temperature oxidation mechanism showed that the oxidation resistance of the coating was mainly due to the generated relatively continuous oxide film Cr2O3 and spinel structure oxide compound such as NiCr2O4, which inhibited the process of internal metal oxide, reduced the oxidation rate of the coating, and improved the oxidation resistance of the coating.6. The corrosion resistance of coatings was improved in chloride content with the increase of Cr. For the following reasons: First, a continuous compact and uniform Cr2O3 oxide film played an important role. Second, the void was filled by spinel complex oxide, which reduced the reactants through the oxide film to the micro-channel which have led to localized corrosion damage.7. When the ingredients uniform, low dense coating was placed in the chloride solution. For the chloride ion erosion, weak area of the passive film coating or defective parts first appeared dissolved.
Keywords/Search Tags:chloride corrosion, arc spraying, cored wire, coating, waste incineration
PDF Full Text Request
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