Evaluation of Dezincification Corrosion of Brass By Complex Capacitance

Wednesday, October 14, 2015
West Hall 1 (Phoenix Convention Center)
K. Tabei, Y. Hoshi, I. Shitanda (Tokyo University of Science), and M. Itagaki (Tokyo University of Science)
An electrochemical impedance spectroscopy (EIS) was used in order to discuss the detailed dissolution mechanisms because the EIS enables us to discriminate the time constants of elementary steps in the dissolution process. The capacitive loop related to the electrode/solution interface is often observed in the impedance spectrum in the high frequency range when the metal is immersed in the electrolyte solution. Since the electric-double layer capacitance Cdl is related to the surface area and structure of electrode/electrolyte interface, it is generally estimated by the curve fitting of the result of the impedance spectrum. Our group [1] previously reported the calculations of the electrochemical impedance and complex capacitance corresponding to typical equivalent circuits because the precise value of Cdl could be estimated by the capacitance plot. The complex capacitance analysis was applied to the evaluation of the performance of energy conversion devices [2-5].

In the present study, the complex capacitance analysis was applied to evaluation of dezincification corrosion of brass. It is important to estimate the precise value of Cdl because a porous Cu-enriched layer is formed on the brass surface due to the selective dissolution of Zn from brass surface [7]. The evaluation method of the dezincification of brass by capacitance plot was proposed.


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