Acta Phys. -Chim. Sin. ›› 1993, Vol. 9 ›› Issue (01): 99-102.doi: 10.3866/PKU.WHXB19930117

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Influence of Chloride Ions Upon Semiconductor Properties of Oxide Films on Copper and Brass

Pan Chuan-Zhi; Yang Mai-Zhi; Cai Sheng-Min; Zhou Guo-Ding   

  1. Department of Chemical Engineering, Zhejiang Institute of Technology; Chemistry Department, Peking University, Beijing 100871; Shanghai Institute of Electric Power
  • Received:1991-08-06 Revised:1991-12-24 Published:1993-02-15
  • Contact: Yang Mai-Zhi

Abstract: The photocurrent-potential relationship for copper and brass electrodes under periodic illumination was obtained during slow (6 mV·s~(-1)) cyclic potential scans with lock-in amplifier in 0.1 molo·L~(-1) Na_2B_4O_7 contianing variable concentration of NaCl. Only cathodic photocurrent was exhibited on photocurrent vs. potential curves in absence of or in the presence of low concentrations of chloride ion in the solution. The minimum concentration of NaCl at which an anodic photocurrent peak appeared is 7.5×10~(-4) g·g~(-1) for copper and 3.8×10~(-3) g·g~(-1) for brass. With the continuous increase of NaCl concentraton the peak area of anodic photocurrent increases and that of cathodic decreases. The appearance of anodic photocurrent peak and its magnitude on photocurrent vs. potential curve may be served as a criterion for the characterization of the corrosion extent of copper material by Cl~-.

Key words: Copper, Brass, Photocurrent, Corrosion, Influence of Cl-