| Zinc alloy as a new kind of protective coating has been widespread attention, with it’s have good formability and weldability, painting, has been widely used in aerospace, automobile, electronics and other industrial steel products in the protective layer. Traditional zinc nickel alloy production method is melting and electroplating.The melting method poor dispersion degree, low nickel content in the alloy, do not conform to the requirements of the current corrosion. Plating mainly has two acidic and alkaline aqueous solution, due to it is not friendly to the environment, so its application in the industry is affected. Zinc magnesium alloy production methods have hot plating, vacuum plating, molten salt, electroplating, vapor deposition, etc. Now the focus of zinc magnesium alloy coating is mainly in sulfuric acid aqueous solution, the content of magnesium in the coating was low. Therefore, to seek a kind of low cost, simple technology, green environmental protection of zinc alloy preparation method has the vital significance. Based on the above situation we use EG-ZnCl2 and Urea-ZnCl2-NiCl2 ionic liquids, has carried on the nickel zinc alloy and zinc magnesium alloy electroplating research. Two kinds of electrolytes, not only has the advantages of green environmental protection, and has low cost, simple system, the air is not sensitive to wait for a characteristic, can be exposed in the air, in line with the requirements of sustainable development of green manufacturing process.The conductivity of ZnCl2, NiCl2, Urea with different content conductivity have determined; the electrochemical properties of Zn Ni alloy were studied by chronoamperometry and cyclic voltammetry; Using the response surface methodology to optimize the deposition conditions; Analyses the coating by EDS and XRD. The results show that when the molar ratio of ZnCl2 NiCl2 and Urea is 2.9:1.5:16.7, the electrical conductivity of ionic liquids is the best. The relationship between conductivity and temperature conforms to the Arrhenius equation, and the activation energy of ionic liquid solution is 30.733 kJ/mol which is by fitting; Zn-Ni alloys follow the three-dimensional instantaneous nucleation and growth process; With the increase of scan rate in the cyclic voltammograms of Urea-ZnCl2-NiCl2 ionic liquid, the reduction peak current increases gradually; The optimization result of response surface methodology shows that the deposition temperature has little influence on mass fraction of zinc coating and the amount of EG and the interaction of the deposition potential is significant, the optimum condition is that the additive mass fraction is 28.4%, the deposition potential is 2.1 V, the deposition temperature is 358 K; The coating is composed of spherical particles and the average particle diameter is 2.5μm, no cracks, no gap, the coating is composed of ZnNi solid solution, the content of Zn is about 33%.After the addition of EG, the average diameter of coating particles is less than 1μm, the thickness of the coating is less than 20μm, the combination of coating and substrate is good, the distribution of Zn and Ni elements in the coating is uniform, Zn and Ni formed a uniform alloy.With deposition potential, deposition time, deposition temperature are 2.5V,2h, 353.15K, pure copper as cathode, graphite sheet as anode.5% NaOH as additive in EG-ZnCl2-MgCl2 system are successfully prepared the Zn-Mg alloy. Electrochemical properties of the system was studied by cyclic voltammetry. The coating were analyzed by EDS, XRD and XPS etc. The results show that depositing Zn-Mg alloy is a step by step process. The first occurrence is the reduction of Zn, after is Zn-Mg; The coating results show that the coating is porous flocculent; Mg and Zn formed a solid solution of amorphous, the existing form of magnesium were Mg and MgO, the form of zinc in metal. |
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