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Study On High Temperature Corrosion Resistance And Mechanisms Of Fe/Cr Coatings For Protection Of Boilers In Coal-burning Power Plants

Posted on:2007-07-03Degree:MasterType:Thesis
Country:ChinaCandidate:S ZhangFull Text:PDF
GTID:2121360185992415Subject:Materials science
Abstract/Summary:PDF Full Text Request
The corrosion in high temperature of boilers' four tubes had become a difficult techno-problem, because it severely impacts the running of boilers and maybe takes huge economic loss. So, in order to improve the superficial quality and the dependability and security, it's very necessary to develop one effect coating-protect method. Thermal spraying is remarkable one because of its advantages, especially arc spraying, including simple equipment, low cost, convenient operation, besides, for the fense and repair of good-sized equipments' heated sides, the method is more effective.In this paper, four kinds of cored wires, Fe-Cr course for thermal spray were made, and with arc wire spray technique, high-temperature corrosion resistance coatings were got. According to studying the high temperature oxidation and hot corrosion, with surface engineering technology, a new coating was obtained which adapt to high temperature corrosion resistance. In this study, microstructure of coating produced by arc spray have been analyzed by using modern testing techniques, such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffractometry (XRD) and energy dispersive spectrometry (EDS), light microscope technique, et al. The bond strength, microhardness, thermal shock resistance, wear-resistant feature, high-temperature corrosion resistance of coatings produced by arc spray have been studied through a series of experiments. Main results are summarized as follows: The coatings have high density, high bond strength, excellent thermal shock resistance. It is difficult to carry out on the surface of base metal. Wear resistance feature of the coating is far better than 20g steel. The Cr2O3 and spinel structure oxide formed firstly can effectively restrain the corrosion, so the Fe/Cr coatings have excellent high temperature corrosion resistance. Arc spraying using Fe/Cr cored wires being a new type, high quality, high efficiency, and low cost technique to produce high temperature environment and corrosion resistant coating, has excellent potential for industrial application in the protection of four tubes of boilers in heat-engine plant.
Keywords/Search Tags:four tubes of boiler, high temperature corrosion, arc sparying, cored wire, coating
PDF Full Text Request
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