Effect of benzotriazole on surface processes during copper electrodissolution in sulfuric acid

• Published in: Journal of the Electrochemical Society Vol. 138; no. 1; pp. 25 - 33
• Main Authors: CLERC, C, ALKIRE, R
• Format: Journal Article
• Language: English
• Published: Pennington, NJ Electrochemical Society 1991
• Subjects: 360105 - Metals & Alloys- Corrosion & Erosion; 400400 - Electrochemistry; Applied sciences; AZOLES; CHEMICAL REACTIONS; CHEMISTRY; COPPER; CORROSION; Corrosion mechanisms; CORROSION PRODUCTS; DISSOLUTION; ELECTROCHEMICAL CORROSION; ELECTROCHEMISTRY; ELECTRODES; ELEMENTS; Exact sciences and technology; HETEROCYCLIC COMPOUNDS; HYDROGEN COMPOUNDS; INORGANIC ACIDS; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MATERIALS SCIENCE; METALS; Metals. Metallurgy; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; SULFURIC ACID; TRANSITION ELEMENTS; Theoretical model; Electrochemical corrosion; Surface layer; Anodic dissolution; Equivalent circuit; Surface film; Copper; Experimental study; Impedance; Benzotriazole; Corrosion inhibitor; Sulfuric acid
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1.2085552

Impedance spectra were obtained during anodic dissolution of Cu in 0.5M H sub 2 SO sub 4 and 40mM benzotriazole (BTA) at 25 deg C. The spectra were evaluated according to the hypothesis that the electrode is covered with a barrier film having a stoichiometric composition through which the current is transported by ionic conduction. This barrier film is itself covered with an outer porous film of corrosion products. The experimental impedance spectra were fit to the model with a nonlinear least squares program. A detailed analysis of the physical parameters obtained with this procedure suggested that the metallic ions transfer through the barrier film, which is likely to be hydrated copper sulfate or contains a non-negligible amount of BTA, under high-field conduction. Experiments carried out at the mass-transfer limiting current in the absence of BTA suggested that the electrode was also covered with a similar dual salt film, the inner layer of which, however, has a different chemical composition than in the presence of BTA. Graphs. 30 ref.--AA