Production of nano-composite by electrochemical process in new solvent

在本研究中，我们使用了一种新的电化学溶剂TMHA-Tf_2N，但其性质尚不清楚。因此，收集这种新型溶剂的基本性质，如含水量、运动粘度、电导率等的测量是一个非常重要的问题。结果表明，TMHA-Tf_2N的运动粘度随温度和含水量的增加而降低。另一方面，电导率随温度和含水量的增加而增加。电镀Cu-Sn合金的方法之一是在Cu基体上电还原Sn，使其相互扩散形成Cu-Sn合金。要实现这种方法，扩散系数必须很大。因此，TMHA-Tf_2N的优势在于它在高于100℃左右的温度下是稳定的，并且在更高的温度下，扩散系数也高。结果表明：(1)通过循环伏安分析发现，在高于0 V的电压范围内，在高于锡电极自然电压的电压下，锡离子（II）被还原为金属锡。(2)离子液体采用接触电沉积。所得铜锡合金呈金属白色银色。合金的组成为Cu_6Sn_5， Cu_3Sn, Cu_<10>Sn_3。在水溶液中，150C时的成膜速率是90c时的3倍。这意味着该离子液体具有用于高温电镀的良好性能。(3)在Cu衬底上进行恒电位电解时，形成何种金属间化合物取决于外加电压。在低于+40 mV的电压下，可以得到金属白色的银；高于+50mV时，只得到黑色的银膜。(4)我们还将电接触法应用于薄铜膜。

In this study, we used TMHA-Tf_2N which is a new solvent for electrochemistry, but whose properties has not known well. Thus it is quite important issue to collect basic properties of this new solvent, for example, water content and kinematic viscosity, electrical conductivity were measured. As the results, kinematic viscosity of TMHA-Tf_2N was found to decrease with temperature and water content. On the other hand, the electrical conductivity increased with temperature and water content. As one of method to electroplate Cu-Sn alloy, we carried out electroreduction of Sn on Cu substrate and allowed mutual diffusion to form Cu-Sn alloy. To achieve this method, the diffusion coefficient has to be large. Thus, TMHA-Tf_2N has advantage because it is stable higher temperature than about 100 C, and at the higher temperature, the diffusion coefficient is high. As the results, (1) It was found that tin ion(II) was reduced to metallic tin at a higher voltage than natural voltage of tin electrode by cyclic voltammogram in the higher voltage range than 0 V. (2) Contact galvanic deposition was employed in ionic liquid. Obtained Cu-Sn alloy showed metallic white silver color. The composition of the alloy was Cu_6Sn_5, Cu_3Sn, Cu_<10>Sn_3 It is noted that the rate of film formation was three times larger at 150C than that at 90 C in aqueous solution. This implies the promising properties of this ionic liquid for a higher temperature electroplating method. (3) In potentiostatic electrolysis on Cu substrate, what intermetallic compound formed depends on applied voltage. At voltage lower than +40 mV, metallic wihite slver was obtained but higher than +50mV only black film was obtained. (4) We also applied the galvanic contact method to thin cupper film.