| Unlike traditional materials, nanomaterials has many advanced properties which due to small particle size, narrow size distribution, low levels of agglomeration and high dispersibility. As a kind of special nanomaterials, nano-scale multilayer has more characteristics than normal nanometerials for its period modulate structure. Nowadays lots of nano-mutilayer sensor development and applications are in progress which based on its giant magnetic resistance. Meanwhile the research on its excellent corrosion resistance and mechanical properties become a hot topic in nano-technology.Various aspects performance, application focus, the current number of academic progress and preparation methods in nano-mutilayer were described in this paper. The preparation of Cu/Ni nano-multilayer in Single-bath method which progressed in potential pulse was specially discussed. The composition of electrolyte was confirmed as below:lmol/L NiSO4·6H2O, 0.01mol/L CuSO4·5H2O, HBO340g/L, 0.1g/L Sodium dodecglsulphate,0.05g/L Sodium dobecylbenzenesulfonate, lg/L Saccharin Sodium,0.5g/L NaCl. Other parameters were set as below:-0.6V for depositing Cu,-1.1V for depositing Ni,50℃for electrodepositing. The relationship between its structure and characterize (mechanical and corrosion resistance) were also specially discussed. The results were found as below:The micro-rigidity peaks were observed when the modulate wavelength of multilayer arrives at 10nm,50nm,70nm, 100nm. When the wavelengths were 100nm and 6nm, the maximal and minimal micro-rigidity were observed as 538HV and 105HV separately. The wavelength were changed from 10nm to 40nm, the micro-rigidity of multilayer and the wavelength were fitted as Hall-Petch relationship. At the same time, the wavelength decreased, the micro-rigidity was getting larger. The wavelength of multilayer which constituted by Cu(2nm) and Ni(4nm) was annealed at 200℃in 1h and 2h, at 250℃in 1h, the micro-rigidity were equal feckly.After annealed at 250℃at 2h, the micro-rigidity of the multilayer arrived at 339HV. After annealed at 300℃at 1h and 2h, the micro-rigidity were basicly same.The wavelength increased, the corrosive potential of multilayer become more negative. The best corrosion resistance of multilayer was found as its wavelength arrived at 40nm. The cross section of multilayer was observed clearly. The XRD analysis of multilayer was taken, and no alloy peak was found. It was inferred that Cu and Ni was separate without diffusing into alloy. Meanwhile the multilayer transformed to supper-lattice structure when its wavelength debased at 30nm.The method of electrodepositing nano-multilayer is viable, cheap, and promising for its excellent samdwich. But there are still problems before it was manufactured widely:How to change the substrate mechanically between different electrolyte when the dual-baths method was applied and how to cut down the preparation time when the single-bath method was used. The problems were probably solved as below:To the dual-baths method, the relative program and sensor could be invented for automatically controlling the electrodepositing progress. To the single-method, on one hand, the complexing agent of the nobel metal could be invented for accelerating the rate of electrodepositing the nobel metal. On the other hand, the composing of electrolyte could be changed for electrodepositing alloy film instead of pure metal film, and it could increase the content of the nobel metal, in one word, it could cut down the preparation time. |
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