【作者】 范毅；

【导师】 丁彰雄；

【作者基本信息】 武汉理工大学 ， 载运工具运用工程， 2006， 硕士

【摘要】 轴流式引风机是锅炉的主要辅助设备之一,担负着连续输送气体的任务。轴流式引风机的失效形式主要表现为烟气中的固体颗粒对轴流式引风机叶片的冲蚀磨损,轴流式引风机叶片的失效会导致出力效率降低甚至停机。在能源越来越受到重视的现在,轴流式引风机叶片的抗冲蚀研究显得愈加重要。 本文在综合国内外关于轴流式引风机叶片冲蚀领域的研究文献的基础上,以冲蚀机理为依据,采用火焰喷熔工艺制备了NiWC35、Ni60、SNi46和SNi67喷熔层,采用电弧喷涂工艺制备了LX88A金属陶瓷复合涂层,采用HVOF工艺制备出微米WC/12Co和纳米WC/12Co金属陶瓷复合涂层。通过试验对涂层结合强度、涂层硬度及涂层抗冲蚀性能等性能进行了研究,并通过金相观察、扫描电镜（SEM）、电子探针能谱分析（EPMA）和X射线衍射相分析（XRD）对涂层的显微组织及元素分布进行分析,探讨了涂层抗冲蚀的机理,在此基础上,将几种涂层的抗冲蚀性能进行了比较。 分析表明:三种喷涂（熔）工艺制备的涂层,如火焰粉末喷熔层、电弧喷涂层和HVOF涂层都有很好的抗冲蚀性能,其中以HVOF工艺制备的涂层抗冲蚀性能最佳,其次分别为火焰喷熔层和电弧喷涂层。由于加入了35%金属陶瓷WC,提高了NiWC35喷熔层的硬度,使得NiWC35喷熔层的抗冲蚀性能强于其他三种喷熔层。电弧喷涂LX88A金属陶瓷涂层由于在电弧喷涂过程中发生化学反应生成含有金属陶瓷硬质相Fe₃B,因此具有优良的抗冲蚀性能。采用HVOF工艺制备的微米和纳米WC/12Co金属陶瓷涂层都具有优秀的抗冲蚀性能,其中纳米WC/12Co涂层抗冲蚀性能最佳,这是因为纳米WC/12Co粉末颗粒微小,在涂层制备过程中,粉末受热更均匀,变形更充分,结合强度更高,塑性更好,因此冲蚀性能更优异。 综合以上结果,确定4种金属陶瓷涂层具有优秀的抗冲蚀性能,NiWC35喷熔层和电弧喷涂LX88A涂层由于制备简单,可进行现场施工,将会被广泛的应用。纳米WC/12Co涂层性能最为优良,它具备更高的结合强度、更好的塑性和更好的抗冲蚀性能。目前HVOF工艺在国外已得到了普遍的应用,在国内可望在轴流式引风机叶片的防磨处理上有更多的应用。更多还原

【Abstract】 Axial flow fan is a main device of the boiler, which has the task of continuous gas transportation. Erosion of the blade by the solid particle of the smoke and gas is the major problem of axial flow fan, which may make axial flow fan reduce power and even stop working. Today with the worldwide attention to energy, study on erosion of axial flow fan becomes more and more important.On the basis of literature search on erosion of axial flow fan’s blade, depending on the failure mechanisms, several kinds of coatings were prepared. NiWC35, Ni60, SNi46 and SNi67 spraying and fuzing coatings were prepared by spraying and fuzing. Cermet composite coating of LX88A was prepared by arc spraying. Cermet composite coatings of conventional WC/12Co and nanostructured WC/12Co were prepared by HVOF. The bonding strength, hardness and erosion of coatings were studied by some tests. The mechanisms of erosion were explored by analyzing the microstructure and distribution of element of coatings with the techniques of metallographic analysis, Scanning Electron Microscope （SEM）, Electron Probe Micro-Analysis （EPMA） and X-Ray Diffraction （XRD）, and the anti-erosion performance of several kinds of coatings above were compared.The study shows that the coatings prepared by three kinds of spraying processes all do well in anti-erosion performance. The coating prepared by HVOF is the best one of them. The coatings prepared by spraying and fuzing are better than the coating prepared by arc spraying. The anti-erosion performance of NiWC35 spraying and fuzing coating is better than other spraying and fuzing coatings because of 35% cermet WC in it. The anti-erosion performance of LX88A cermet composite coating is good because of the cermet Fe₃B which is produced in the process of arc spraying. Nanostructured WC/12Co coating shows better properties in density, hardness, bonding strength, toughness and anti-erosion than the conventional.Considering the results above, four kinds of the cermet coatings possess excellent anti-erosion performance. NiWC35 spraying and fuzing coating and LX88A coating would be applied abroad, because the process is simple and thedepositing can be carried out on the spot. Nanostructured WC/12Co coating is expected abroad applied inland in the prevent of axial flow fan’s blade for its best strength, toughness and anti-erosion performances, while the technology of HVOF has been abroad applied overseas.更多还原