预镀镍对化学镀Ni-P-PTFE复合涂层结构和性能的影响

Influence of Pre-nickel Plating on Micro-structure and Properties of Electroless Ni-P-PTFE Composite Coating

本文研究了预镀镍过程中不同电流密度和不同沉积时间下形成的预镀镍层对Ni-PPTFE(Poly tetra fluoro ethylene)复合涂层的微观结构和力学性能的影响。首先对304不锈钢基体进行合理的前处理,然后在基体上闪镀一层镍,最后在基体上进行化学镀Ni-P-PTFE复合涂层。通过控制预镀镍过程中的电流密度和沉积时间,利用电子扫描显微镜(SEM)、X射线衍射仪(XRD)、纳米压痕仪、WS-2005涂层自动划痕仪、HSR-2M摩擦磨损试验机对复合涂层的微观结构和力学性能进行了表征。结果表明:不同电流密度和不同沉积时间下形成的预镀镍层对Ni-P-PTFE复合涂层的微观组织、涂层硬度、结合力和摩擦系数都具有较大的影响。当电流密度为3.3A/dm^2,沉积时间为6min时,NiP-PTFE复合涂层的综合性能最佳,复合涂层的表面光滑均匀,其硬度和结合强度分别达到3.874GPa和27.45N,表面摩擦系数为0.145。

The effects of pre-nickel plating by different current density and deposition time on microstructure and mechanical properties of Ni-P-PTFE composite coating were studied in this paper. Firstly, the 304 stainless steel substrate was properly treated, then a nickel layer was deposited on the substrate （pre- nickel plating）. Finally, Ni-P-PTFE composite coating was deposited on the substrate by electroless coating. The current density and deposition time were well controlled in the process of pre-nickel plating before the eleetroless coating. The microstructure and mechanical property of the final coated composite were characterized useing scanning electron microscopy （SEM）, X-ray diffraction （XRD）, Nano Indenter, ws-2005 coating automatic scratch instrument and HSR-2M friction wear testing machine. Experimental results show that the pre-nickel plating layer by different current densities and different deposition time have great influences on microstructure, coating hardness, adhesion and friction coefficient of the Ni-P-PTFE composite coating. When the current density is 3.3A/dm^2 and deposition time is 6 minutes, comprehensive performance of the Ni- P-PTFE coating is the best and the surface of the composite coating is smooth and uniform. The hardness and bonding strength reached 3. 874GPa and 27.45N, respectively, and the surface friction coefficient was 0. 145.