Study On Electrodeposition Process Of Functional Ni-based Coatings

Because of its variety and excellent function,nickel-based functional coatings are widely used in the field of high technology.In the National Science and Technology Development Regulation,this technology is listed as the most important.In order to further improve the process stability of nickel based functional coatings,enhance the wear resistance、 high temperature oxidation resistance and corrosion resistance of the coatings,this study determined three best electrodeposition processes of N i-Ti C、N i-Zr O2、Zn-Ni,and tested the phase functions of the coatings.The watt-type plating solution is prepared and N i-Ti C composite coating is electrodeposited on the surface of the steel sheet.The study discuss the effect of the Ti C concentration、 cathode current density、plating solution PH value、 stirring speed and other technological parameters on the coating Ti C content and make the orthogonal optimization,The microscopic morphology of the coating was studied.The results show that the optimal process parameters of electrodeposition N i-Ti C composite coating are as follows:Ti C concentration 50g/L、current density 1.5A/dm²、PH 3.5、Stirring Speed 600r/min、 Bath Temperature 30℃、 platingtime 60 min.It get the N i-Ti C composite coating of good corrosion-resistant,wear resistance is better than Ni、Cr coating.Electrodeposition Ni-ZrO₂ composite coatingon copper substrates,using hardness tester 、 Electrochemical Workstation 、the electric furnace etc,the hardness 、corrosion resistance and high temperature oxidation resistance of the coating are determined.The optimum technological conditions were determined by ortho gonal test.The results showed that optimal process parameters of electrodeposition N i-ZrO₂ composite coating are: ZrO₂ concentration 15g/L、 current density 20 m A/cm²、 electroplating time 30min、 bath temperature 45℃.The hardness、 corrosion resistance、 and high temperature oxidation resistance of the Ni-Ti C coating are superior to the pure nickel coating.Electroplating Zinc-nickel alloy on copper and iron-based bodies.By controlling different current density、 temperature、PH value、 brightener to determine the corrosion polarization curve、Tafel curve、 cyclic voltammetry curve and AC impedance in 3.5% brine.The thickness and corrosion resistance of the coating were compared,the best conditions were determine.coating appearance is observated by electron microscope,the corrosion resistance of the coating was studied by the 5% brine test.The results show that the optimal process conditions are Zn C l2 130g/L、 KC l 200g/L、 N i C l `6H₂O 160g/L、 brightener 45ml/L、 complexing 45g/L、Slow granule 65g/L、cathode current density 3A/dm² 、 stir 50 turn /min、 temperature 350 C,p H 5.5.Under the above process conditions,thickness of the coating is 18.8μm,corrosion resistance is 5 times of galvanized layer.Corrosion resistance is superior after passivation.