激光熔覆NiCr涂层的结构及摩擦学性能

Microstructure and Tribological Properties of Laser Cladding NiCr Coating

利用激光熔覆技术在纯钛表面制备了NiCr涂层。用X射线衍射仪(XRD)和扫描电镜(SEM)分析了涂层的组成和组织结构。在UMT-2MT摩擦磨损试验机上对NiCr涂层在不同载荷和不同滑动速度下的摩擦磨损性能进行了测试。结果表明:NiCr涂层的主要组成物相为NiTi、Ni3Ti、Ni4Ti3、Cr2Ni3和Cr2Ti,涂层与基材冶金结合,涂层晶体结构主要为树枝状晶,涂层的平均显微硬度约为780HV0.2,涂层的摩擦因数随载荷和滑动速度的增加而减小;磨损率随载荷的增加而增加,随滑动速度的增加而减小。涂层的磨损率在10-6 mm3/Nm数量级,具有优异的耐磨性能。

NiCr coating was produced on pure Ti substrate by laser cladding technology.The composition and microstructure of the fabricated coating were analyzed by X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The tribological properties of the NiCr coating were examined by UMT-2MT tester at different normal load and sliding speed.The results show that the NiCr coating mailnly contains NiTi,Ni3Ti,Ni4Ti3,Cr2Ni3 and Cr2Ti phases.The prepared NiCr coating is metallurgically bonded to the titanium substrate,and the NiCr coating contains dentritic microstructure.In addition,the average microhardness of the NiCr coating is 780 HV0.2.The friction efficient of the NiCr coating decreases with increasing normal load and sliding speed.The wear rate of the NiCr coating increases with increasing normal load while deceases as the sliding speed increases.Under all wear condition,the wear rate of the NiCr coating is in the 10-6 mm3/Nm order of magnitude with excellent wear resistance.