| Ni-PTFE composite coatings are obtained by dispersing high molecular polymermaterial Teflon(PTFE) micro particles into the Ni plating solution, which have betterself-lubrication and corrosion resistance than the single Ni coatings. In order to improve theproperties of Ni-PTFE coatings, and obtain low steady friction coefficient and certaincorrosion resistance, the composite electronic coatings preparation by the addition of PTFEmicro particles to Ni matrix and Sn-Ni matrix were detailed analyzed in this paper. The mainstudy focused on preparing excellent and integrated performance coatings by optimizingparameters in the process of plating in the paper.Firstly，the experiment scheme was designed. Ni-PTFE and Sn-Ni-PTFE two compositecoatings were prepared. Based on the electrodeposited composite coatings’ theoreticalanalysis, the coatings’ microstructure, component, interfacial bonding state, microhardness,corrosion resistance were studied by using SEM, EDS, microhardness instrument andelectrochemical workstation. Meanwhile, the influencing factors on the properties of coatingswere studied, which consisted of solution temperature, cathode current density and the addingquantity of PTFE particles. The tribological properties of coatings were tested by friction andwear experiments device.Through observing the pictures of Ni, Ni-PTFE, Sn-Ni and Sn-Ni-PTFE by SEM, it isfound that the crystalline grain size of the coatings were small, the surface of the coatingswere smooth, and the microstructure was dense and uniform. PTFE micro particles wereembedded firmly and dispersed uniformly in the composite coatings of Ni-PTFE andSn-Ni-PTFE. The concentration of PTFE in Ni-PTFE and Sn-Ni-PTFE coatings wererespectively about9%and12%. Moreover, the concentration of Sn in Sn-Ni-PTFE coatingswas approximately73%.The microhardness test on the coatings indicated that the hardness of Ni, Ni-PTFE,Sn-Ni, Sn-Ni-PTFE were respectively580HV,530HV,560HV,540HV. From the contrastmicrohardness of Ni-PTFE and Sn-Ni-PTFE coatings, it can be concluded that themicrohardness of coatings decreased with the increase of PTFE particles in the platingsolution due to the lower microhardness of PTFE. By testing Tafel polarization curve of all the coatings in the corrosion solution, it wasfound that the corrosion potential of Sn-Ni-PTFE was more close to zero than that of Ni,Ni-PTFE and Sn-Ni coatings, whose corrosion current was lower and resistance value wasmuch higer. The results showed that Sn-Ni-PTFE owned more outstanding corrosionresistance.Via the measurement of friction and wear behavior on the composite coatings, it couldbe concluded that the more the adding quantity of PTFE micro particles, the better the frictionand wear performance of the coatings. The grinding crack of coatings’ surface were smooth.The tribological properties of Sn-Ni-PTFE were better than that of Ni, Ni-PTFE and Sn-Nicoatings, and its friction coefficient was about0.15.In summary, the coating with homogeneous dense, good tribological properties andcorrosion resistance was obtained in the paper. The results showed the optimum processconditions in preparing composite coatings of Ni-PTFE and Sn-Ni-PTFE were as follow:temperature50℃and47℃distinctly, the cathode current density2.4A/dm2and0.6A/dm2respectively, and the top adding quantity of PTFE particles were both10ml/L. |
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