Electrochemical behavior of aluminum bronze in sulfate-chloride media

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• 作者：Waheed A. Badawy ; Rabab M. El-Sherif and Hassan Shehata
• 关键词：Aluminium bronze ; Corrosion ; Chloride ; Cyclic voltammetry ; Impedance ; Sulfate
• 刊名：Journal of Applied Electrochemistry
• 出版年：2007
• 出版时间：October, 2007
• 年：2007
• 卷：37
• 期：10
• 页码：1099-1106
• 全文大小：543 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Electrochemistry
  Physical Chemistry
  Industrial Chemistry and Chemical Engineering
  
• 出版者：Springer Netherlands
• ISSN：1572-8838

文摘

The electrochemical behavior, especially the corrosion and passivation, of a Cu–Al bronze was investigated. Conventional electrochemical techniques including open-circuit potential, anodic polarization, cyclic voltammetry and electrochemical impedance spectroscopy were used. It was found that the addition of chloride ion up to 0.15 M in 0.5 M Na₂SO₄ solution decreases the corrosion rate due to the formation of CuCl, whereas at higher concentration of the chloride ion, the corrosion rate increases due to the formation of the soluble CuCl₂−. The activation energy was found to be 10 kJ mol−1. This value indicates that the corrosion process is under diffusion control. The impedance measurements showed that the passive film can be represented by a duplex layer, a relatively thick porous outer film on top of a thin compact layer. An equivalent circuit was used to explain and analyze the impedance data. The model includes another R-C combination and Warburg impedance in addition to the simple Randles cell to account for the spontaneously formed passive film and the diffusion phenomena.