【作者】 张忠；

【导师】 刘洪喜；

【作者基本信息】 昆明理工大学 ， 材料成型与控制， 2012， 硕士

【摘要】 本文采用同步侧向送粉激光熔覆技术,用C02激光器在45钢表面制备了Ni60WC25、Ni60WC35和N i60WC35A11.2三种成分的WC颗粒增强相复合涂层。着重分析WC颗粒增强相复合涂层的物相组成、微观形貌、显微硬度和耐磨损等力学性能,旨在利用激光熔覆表而改性技术解决45钢表面显微硬度低和耐磨性较差等材料固有性能的不足提供理论参考并积累一定的工艺经验。运用X射线衍射仪(XRD)测试了不同成分配比下所得WC/N i60复合涂层的物相分别进行了定性分析；借助扫描电镜(SEM)并结合EDS能谱分析研究了不同成分配比下WC/N i60复合涂层微观形貌的影响规律；采用显微硬度计测试了三种成分WC/Ni60复合涂层截面的显微硬度；采用MMU-5G型屏显式材料端面高温摩擦磨损试验机测试了三种成分WC/N i60复合涂层端面的抗磨损性能。XRD物相定性分析,证实了N i60WC25和N i60WC35复合涂层主要物相由γ-(Ni,Fe)、Cr7C3、Fe23(C,B)6、Ni2W4C、FeNi3、WC、B4Cr3组成；Ni60WC35A11.2复合涂层主要物相由γ-(N i,Fe)、Fe23(C,B)6、AlB12、FeNi3、Cr7C3、Al5Fe2、Ni2W4C、B4Cr3、WC组成。Ni60WC25粉末中大部分WC颗粒分解破碎,未熔解的WC颗粒沉积到涂层中底部,Ni60WC35和N i60WC35Al1.2粉末中WC颗粒发生少量分解,表面分解的WC颗粒周围形成富含W和C元素的区域,形成Ni2W4C等M7C3型和M23C6型碳化物,呈多变形状或针状。Ni60WC25、Ni60WC35和Ni60WC35Al1.2三种复合涂层的显微硬度依次为HVo.2611、HV0.2670和HVo.2670；显微硬度波动幅度依次减小证明后两组复合层的硬度更加稳定。Ni60WC25、Ni60WC35和Ni60WC35Al1.2三种复合涂层的平均摩擦系数分别为fa=0.547、fa=0.519和fa=0.415；摩擦系数波动幅度依次减小,磨损量依次为3.1mg、1.8mg和1.4mg。Ni60WC35Al1.2复合涂层其磨损表面存在大量针状物相,针状物相围绕在WC颗粒周围提供了很强的包裹力,细小均匀分布的A1B12、Al5Fe2和Fe23(C,B)6物相针状物相使得Ni60WC35Al1.2复合涂层的摩擦磨损过程中震动微弱更加平稳,具有更好的耐磨性。更多还原

【Abstract】 In this paper, using synchronous lateral powder feeding laser cladding, prepared Ni60WC25, Ni60WC35and Ni60WC35A11.2three kinds of WC particles reinforced composite coating in the45steel surfaces. Focus on analysis of the WC particle reinforced phase composite coating phase composition, morphology, and mechanical properties of microhardness and wear resistance, aiming to solve the45steel surface the inherent performance defects of hardness and wear resistance and provide theoretical basis and certain technology foundation by laser claddingThe phase qualitative of composite coating under different composition ratio of WC/Ni60by X-ray diffraction (XRD); The microstructure feature of composite coating under different composition ratio of WC/Ni60was characterized by scanning electrical microscope and energy (EDS). The microhardness of samples section was tested by microhardness instrument. The wear resistance of samples end was tested by MMU-5G wear instrument.The qualitative analysis to confirm the phase species. Ni60WC25and Ni60WC35main phase γ-(Ni,Fe)、Cr7C3、Fe23(C,B)6、Ni2W4C、FeNi3、 WC、B4Cr3; Ni60WC35Al1.2main phase γ-(Ni,Fe)、Fe23(C,B)6、AlB12、 FeNi3、Cr7C3、Al5Fe2、Ni2W4C、B4Cr3、WC.Ni60WC25most of the WC particles dissolved broken, undissolved of WC particles deposited on the bottom of the coating.the Ni60WC35and Ni60WC35Al1.2surface of WC particles occurred to a small dissolved, dissolution of WC particles surface formed around a region rich in W and C elements, the formation is Ni2W4C、M7C3and M23C6carbide and morphology was changing shape or needle shape. Three kinds of Ni60WC25, Ni60WC35and Ni60WC35Al1.2composite coating microhardness were HV0.2611, HV0.2670and HV0.2670; microhardness fluctuations decreases in turn, to prove that the latter two groups of hardness is more stableNi60WC25、Ni60WC35and Ni60WC35Al1.2three kinds of composite coating the average friction coefficient were fa=0.547、fa=0.519and fa=0.415; in turn reduce the fluctuations of the friction coefficient, amount of wear were3.1mg、1.8mg and1.4mg. Worn surface of Ni60WC35Al1.2composite coating exist a large number of needles, needle phase surround the WC particles that provided a strong parcel force, fine and uniform AlB12、Al5Fe2and Fe23(C,B)6phase uniform distributed makes coating process of friction and wear was more stable and had better wear resistance.更多还原