Factors determining the critical current density for zinc deposition in sulfate solutions
Factors determining the critical current density for zinc deposition in sulfate solutions
复制标题
硫酸盐溶液中锌沉积临界电流密度的决定因素
作者：
Hiroaki Nakano;T. Ohgai;H. Fukushima;T. Akiyama;R. Kammel
研究了锌从硫酸盐溶液中开始沉积的临界电流密度，并以氢的固有沉积或电位为基础。析氢的极化曲线表明，使阴极极化达到锌的平衡电位的氢过电位由两种过电位组成。一种是最小的氢过电位，它主要取决于正极材料；另一种是在溶液中有锌离子存在时出现的超过电位。对阴极附近pH的测量表明，超过电位是由于氢氧化锌吸附在沉积位置上的抑制作用造成的。通过考虑过电势与电流密度的关系，发现临界电流密度的电化学意义是产生使阴极极化到ZA平衡电位所需的过电势的最小析氢速率。根据临界电流密度的含义，讨论了阴极材料、溶液的缓冲容量、溶液中不同的金属离子等因素对临界电流密度大小的影响。
The critical current density at which Zn began to deposit from sulfate solutions was studied an the basis of the inherent deposition orerpotential of hydrogen. The polarization curres for hydrogen evolution indicated that the hydrogen overpotential, which polarized the cathode to reach the equilibrium potential of Zn, was composed of two types of overpotential. One was the minimum hydrogen overpotential, which mainly depended an the cathode material, and the other was the extra-overpotential appearing in the presence of Zn Ions in the solution. The measurement of pH in the vicinity of the cathode revealed that the extra-overpotential was caused by the inhibitory Zn hydroxide adsorbed an the deposition sites for hydrogen. By considering the current density-dependence of the extra-overpotential, the electrochemical meaning of the critical current density was found to be the minimum hydrogen evolution rate which generated the necessary magnitude of the extra-overporential to polarize the cathode to reach the equilibrium potential of Za. The effect of factors such as cathode materials, the buffer capacity of the solution and the different metal ions in the solution, etc., an the magnitude of the critical current density was then discussed according to the meaning of the critical current density.