Electrochemical and Spectroscopic Study of Benzotriazole Films Formed on Copper, Copper-zinc Alloys and Zinc in Chloride Solution

I. Milošev and T. Kosec

Abstract
The formation of protective layers on copper, zinc and copper-zinc (Cu-10Zn and Cu-40Zn) alloys at open circuit potential in aerated, near neutral 0.5 M NaCl solution containing benzotriazole (BTA) was studied using potentiodynamic measurements, electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The addition of benzotriazole affects the dissolution of the materials investigated. Benzotriazole, generally known as an inhibitor of copper corrosion, is also shown to be an efficient inhibitor for copper-zinc alloys and zinc metal. The effectiveness of inhibition depending on the type of materials was compared. X-ray photoelectron spectroscopic results showed that the surface layer formed on alloys in BTA-inhibited solution comprised both oxide and polymer components. The formation of Cu2O/Cu(I)-BTA on copper, mixed oxides/Zn(II)-BTA and Cu(I)-BTA on copper-zinc alloys and ZnO/Zn(II)-BTA polymer surface film on zinc provides an effective barrier against corrosion on materials investigated in chloride solution.

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Keywords
copper, brass, zinc, benzotriazole, EIS, XPS, inhibition