离子软硬度对锌合金电沉积的影响

Effect of Soft-Hardness Degree of Ions on the Electrodeposition of Zinc Alloys

一般说来,金属离子的电沉积基本上决定于金属与相应离子的电极电位,但是在混合离子溶液中有时会遇到电极电位较负的金属优先析出的“异常现象”.作者利用循环伏安法测定了混合溶液的析出电位.并根据离子的软酸碱原理计算了Ahrland标度.对比这个标度,发现金属离子的电沉积不仅与它们的电极电位有关,还与它们的软硬度有关.提出了软度较大的金属离子在双电层中更加贴近阴极的假设.

In general, the electrodeposition of metal ions depends mainly upon their electrode potentials. However, in a solution of mixed metallic ions, sometimes there occurs preferentially deposition of metals with more negative electrode potential. This is known as an 'anomalous phenomenon'. The deposition potentials of the mixed solutions were determined using cyclic voltammetery and the Ahrland hard -soft scales were calculated. It was found that deposition of a metal not only depends upon its electrode potential, but also is related to the hard -soft scale of the metal ion. A hypothesis is advanced that soft ions (larger in hard-soft scale) stay more close to the cathode surface in the double layer.