锌-铁合金电沉积机理研究

Study on the Electrodeposition Mechanism of Zn-Fe Alloy

采用循环伏安法研究了在含柠檬酸的硫酸盐溶液中玻碳电极上锌-铁合金电沉积机理。比较单金属和锌铁共沉积时的伏安行为,发现在本实验条件下,锌、铁和锌-铁合金电沉积都按三维成核/生长机理进行,且不发生UPD过程,但成核过电位却相差较大,电沉积合金时成核过程要比电沉积单金属时容易得多。沉积物中铁含量同溶液中Fe^(2+)离子与沉积金属离子总量之比的关系表明,锌-铁共沉积表现异常现象。实验表明,锌离子阻化铁的沉积;而铁离子则对锌电沉积起一定的促进作用。

The elecctrodeposition mechanism of Zn-Fe alloy onto vitreous carbon from sul-fate solutions containing citric acid were investigated by means of cyclic voltammetry. It was found that, under experimental conditions no UPD process was observed, and the deposition of Zn, Fe or Zn-Fe followed the mechanism of three-dimentional nucleation and growth, but the nucleation overpo-tentials were quite different, the nucleation rate of codeposition was faster than that of individual metals. The dependence of the Fe content in the alloy deposits on the mole percentage of Fe2+ ions with respect to the total deposited metal ions showed that, the codeposition of Zn and Fe behaved anomalously. It was found experimentally that Zn2+ ions inhibit the deposition of Fe, while Fe2+ ions promote the deposition of Zn.