Acta Phys. -Chim. Sin. ›› 2007, Vol. 23 ›› Issue (10): 1525-1530.doi: 10.1016/S1872-1508(07)60077-1

• ARTICLE • Previous Articles     Next Articles

Polarization Characteristic of Iron Anode in the Concentrated NaOH Solution

HE Wei-Chun; SHAO Hai-Bo; CHEN Quan-Qi; WANG Jian-Ming; ZHANG Jian-Qing   

  1. Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China; College of Material Science and Engineering, Henan University of Technology, Zhengzhou 450007, P. R. China; State Key Laboratory for Corrosion and Protection, Chinese Academy of Sciences, Shenyang 110015, P. R. China
  • Received:2007-06-01 Revised:2007-07-09 Published:2007-10-01
  • Contact: SHAO Hai-Bo;

Abstract: Polarization curve, electrolysis curve, and electrochemical impedance spectroscopy (EIS) were adopted to study the polarization of iron electrode in the concentrated NaOH solution. The results showed that passivation of the iron anode occured more easily at higher temperature, lower alkaline concentration, and greater current density. However, the passivation phenomenon of the iron electrode might become too weak to see under some conditions. The conditions were as follows: temperature 25-35 ℃, current density ≤ 4.7 mA·cm-2, alkaline concentration ≥ 14.5mol·L-1. EIS was used to investigate the impedance change of the electrode surface during the above polarization process. Next, the step characteristic of the iron anode polarization during its super-passivation range in theconcentrated NaOH solution was described.

Key words: Iron anode, Passivation, Ferrate(Ⅵ), Electrolysis curve, EIS, Current efficiency