Studies on Nano-Electroplating using Liquid Membrane of Electrolyte Solution in Supercritical CO_2

点击翻译按钮获取中文摘要

The authors have proposed an innovative electroplating technology "Zero-Emission Supercritical Nanoplating", which is a hybrid of supercritical fluid and electroplating technology. In this technology, electroplating reactions are carried out in emulsion of supercritical carbon dioxide (CO_2) and electroplating solution with surfactants. The plated film by this method did not have any pinholes, which come from hydrogen babbles produced by the electrolysis of water. Compared to electroplating from the solution only, higher quality nickel films have been prepared by this method, which have higher uniformity, smaller grain size (about 10 nm), and significantly higher Vickers hardness.We have elucidated the ZSNP reaction by measuring the current values in the emulsion with functions of pressure, surfactant concentration, and the solution/ CO_2 ratio, using minute terminals connected to a programmable power supply, while simultaneously observing the dispersion state of the emulsion through a … More high-pressure view cell, which was designed and produced in this project. The flow of current values in the emulsion system fluctuated, and the current value decreased together with the amplitude of the fluctuant current when the pressure was increased. The fluctuant current flow in the emulsion was concluded to play an important role in the fabrication of the nano grain nickel structure in the plated film.Moreover, we investigated an electroplating reaction in a series of emulsions between an electroplating solution and dense carbon dioxide (CO_2) using a novel fluorinated surfactant F(CF(CF_3)CF_2O)_3CF(CF_3)COO(CH_2CH_2O)_7CH_3. In ZSNP, the polymeric surfactant plays some important roles to stabilize the emulsion, to make the electric current fluctuant by the dispersion state and to control the quality of the plated film.The electroless plating reactions are also carried out in an emulsion of supercritical carbon dioxide (sc-CO_2) and an electroless plating solution with surfactant. The Ni-P film obtained by this proposed technique was a uniform and conformal film without the pinholes that form from the hydrogen bubbles produced by the electrolysis of water, and without the nodules that form from the nuclear growth on the electroless plating reaction. Less