| Using electrochemical deposition technique to obtain a layer of metal functional membrane on the material surface is one of the important technology that can that not be replaced in industrial production.At present, the preparation of the electrodeposition of metals is mainly carried out in aqueous solution system. and people have done many complete and systematic researches about the electrodeposition of metals in the aqueous solution. However, electrodeposition technology that react in traditional water system still exist many disadvantages, such as:(1) electrochemical window of the water is narrow, which can limits the electrodeposition of some metals;(2) it is inevitable to produce hydrogen in the process of electrolytic,so that can makes pinhole defects on coating surface,and because it needs to increase the thickness of the film to reduce the defect rate,which cause a lot of precious metal resources waste;(3) the discharge and productione of a large number of electroplating waste water cause serious environmental pollution problems.Therefore, establishing a new type of green environmental protection electrodeposition technology is important and significant.In 2002, the Japanese Sone team realized plating reaction of metal film in the emulsion system that built by supercritical CO2 and plating solution for the first time.This kind of metal film has high hardness, no pinhole, corrosion resistance,and so on. Compared with the traditional method, it can greatly save the consumption of precious metals and reduce the production of waste water, which provides a new way of thinking for the green of metal electrodeposition technology. The key of the technology is to add a moderate amount of surfactant to reaction system so that it can dissolve a certain concentration of electrolytic brine, which meets the electrical conductivity that the reaction need. However,the fluorine surfactants used in the literature have high prices. On the same time,it’s very difficult to get at home, which limits industrialization application of the technology in the domestic.One purpose of this paper is to find a surfactant which is cheap and can be buy at home, and realizing the preparation of nickel electrodeposition in supercritical CO2 expansion plating solution liquid, which would offer certain reference data for industrial application ofsupercritical electrodeposition technology.Iron-nickel alloy coating has excellent electromagnetic and mechanical properties, and the colour and lustre is bright.On the other hand,the Crystallization of Iron-nickel alloy coating is fine and has good uniformity and corrosion resistance.Iron-nickel alloy coating is widely used that is an important functional membrane materials.Another research purpose of thesis is to explore the possibility that the iron-nickel alloy membrane can be prepare in supercritical CO2 expansion plating solution liquid to broaden the application of supercritical electrodeposition technology in the field of alloy electroplating.The content of this paper mainly included as the following three parts:1.Chose four kinds of fluorinated surfactants, three kinds of organic silicon surfactants and three hydrocarbon surfactants, and addes them in the supercritical CO2- plating solution.By comparing the electrical conductivity of the system and the surface morphology of coating films, determined the best surfactant e2.By using surfactants, probed the effects of the concentration of surfactant e,the system pressure, stirring rate, current density and deposition time on the experiment of high pressure electroplating nickel.Through the contrastive analysis of the surface morphology of coating films and found the best reaction conditions:the pressure is 10 MPa, the surfactant concentration was 0.5%, the current density was 2A/dm2, the stirring speed was 300 r/min,the reaction time is 30 min.In addition,through using SEM, XRD, thickness gauge and hardness tester, contrasted and analysed the nature of the nickel plating under the condition of high pressure and atmospheric pressure.Compared with the nickel film got under atmospheric pressure,although the efficiency of electroplating under high-pressure is slightly lower than electroplating under atmospheric pressure, but the grain size of nickel films obtained under the condition of high pressure were smaller and had more smooth surface.3.On the base of achieving the electrodeposition of nickle under high pressure,discussed the possibility of electrodeposition of nickel-iron under high pressure by using surfactant e.Compared with the nickle-iron coatings got under atmospheric pressure, the grain size of the coatings obtained under high pressure were smaller,the hardness of coatings were bigger and the content of nickel-iron coatings were higher.But because the current efficiency under high pressure is lower than that in atmospheric pressure, which made the thickness of nickle-iron coating under high pressure is less than that under the condition of atmospheric pressure. In addition,compared the nickle coatings and nickle-iron alloy coating got under high pressure,results showed that the hardness and corrosion resistance of nickel-iron alloy coatings were better than that of the nickel coating, and metal particles of nickle-iron coatings were smaller. |
