常温下从离子液体电解液中电沉积金属钴

研究了离子液体镀液中Co、Zn的共沉积行为。ZnCl2-EMIC -CoCl2电解液的循环伏安曲线上出现了三个电流峰，对应的电极电位分别为250mV、50mV、-200mV（vs. Zn2+/Zn）。结合EDS成分分析，可断定这三个电流峰分别对应着Co的电沉积、Co电极上Zn的欠电位沉积和Co-Zn合金的电沉积。恒电位沉积表明，当控制阴极电位在100 mV（vs. Zn2+/Zn）左右时，可得到高纯度的钴镀层；若进行恒电流沉积，则当电流密度为85mA/cm2左右时能够得到高纯度的钴镀层。对Co、Zn的共沉积机理研究表明，Co的电沉积过程和Zn 在Co上的欠电位沉积过程均受扩散过程控制。

Electrodeposition of Cobalt in an Ionic Liquid Electrolyte at Ambient Temperature

The codeposition behavior of Co and Zn in an ionic liquid was investigated. In the cyclic voltammogram of a ZnCl₂‐EMIC‐CoCl₂ ionic liquid, three reduction peaks appeared at 250 mV (peak c₁), 50 mV (peak c₂) and ?200 mV (peak c₃) (vs. Zn²⁺/Zn). According to the component analysis by means of EDS (energy disperse spectroscopy), peaks c₁, c₂ and c₃ correspond to the electrodeposition of Co, the underpotential deposition of Zn on the electrodeposited Co coating and the codeposition of Co‐Zn alloy, respectively. The potentiostatic deposition showed that the electrodeposited coating of high‐pure Co was obtained when the cathodic potential was controlled at 100 mV (vs. Zn/Zn²⁺). The electrodeposition was carried out at a galvanostatic mode, and when the current density was controlled at about 85 µA/cm², the electrodeposited coating of high‐pure Co was also obtained. Studies on the mechanism of codeposition of Co and Zn showed that the electrodeposition process of Co and the underpotential deposition process of Zn on the electrodeposited Co coating were all diffusion controlled.