Acta Phys. -Chim. Sin. ›› 2002, Vol. 18 ›› Issue (10): 934-937.doi: 10.3866/PKU.WHXB20021014

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Fabrication of Composite Scanning Micro pH Electrode and Its Application in Localized Corrosion

Shao Min-Hua;Huang Ruo-Shuang;Hu Rong-Gang;Lin Chang-Jian   

  1. State Key Laboratory of Physical Chemistry for Solid Surfaces, Department of Chemistry, Department of Materials Science and Engineering, Xiamen University, Xiamen　361005
  • Received:2002-01-31 Revised:2002-03-27 Published:2002-10-15
  • Contact: Lin Chang-Jian E-mail:cjlin@xmu.edu.cn

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Abstract: A novel composite scanning micro pH electrode was fabricated. The IrOx-pH electrode produced in a carbonate melts exhibited high stability, a fast potential response and ideal Nernstian response. The slope of the electrode at 15 ℃ was 56.8 mV/pH, which was very close to the theoretical value. The 90％ potential response time for a pH change from 1.75 to 13.90 was less than 0.5 s. The composite scanning micro pH electrode is a promising apparatus for detecting the pH distribution on metal/solution interface. pH image on the surface of Al/Cu galvanic couple showed that both the anodic and cathodic areas could be sensed well. Localized corrosion took place on the interface of Al/Cu couple. The localized corrosion developed with time and pH value around the pitting decreased gradually.

Key words: Al alloy, Localized corrosion, Scanning micro pH electrode, IrOx-pH electrode