Synergistic Effects of Benzotriazole and Copper Ions on the Electrochemical Impedance Spectroscopy and Corrosion Behavior of Iron in Sulfuric Acid

Abstract

Benzotriazole (BTAH) and copper ions exhibit synergistic effects on the electrochemical impedance spectroscopy and corrosion behavior of iron in sulfuric acid. The presence of submicro- and micromolar amounts of Cu2+ ions along with millimolar amounts of BTAH caused order of magnitude increases in the polarization resistance of the iron/acid interface, above those caused by either BTAH or Cu2+ ions (which is equivalent to order of magnitude decreases in the corrosion rate). This was accompanied by a significant decrease in the capacity of the electrical double layer of the interface, which also showed synergistic effects. The results are interpreted in terms of the deposition, on the iron surface, of a protective film composed of a polymeric complex formed from copper ions and adsorbed BTAH that is believed to be of the form [Cu(I)BTA] n . This film inhibits the cathodic partial (hydrogen evolution) reaction, which is the rate-determining step (rds) and hence the overall corrosion reaction. An increase in the concentration of either Cu2+ or BTAH enhances this synergistic effect. However, there is a critical concentration of copper ions (5 × 10-6 M) beyond which further increase decreases the magnitude of the synergistic effect. This is attributed to deposition of metallic copper on the iron surface at higher concentrations of Cu2+ ions, which promotes the rds and hence the overall corrosion reaction. The results are supported by measurements of polarization curves and mass loss under various conditions.

Investigation of dissolution inhibitors for electrochemical mechanical planarization of copper using beta-alanine as a complexing agent

“…The thickness of this chemisorbed film, denoted here as (BTAH) ad , generally is restricted to a monolayer and at low solution concentrations (*1 mM) of BTAH [7]. Anodic formation of the Cu-BTA complex occurs at relatively higher BTAH concentrations (often at [5 mM) [21][22][23]:…”

“…Cu-BTA complex can grow beyond a monolayer, and depending on the magnitude and duration of the applied voltage, can polymerize to build strong surface passivating films [21][22][23]. In addition, the anodic current contribution of Cu-BTA formation can affect the analysis of corrosion parameters in BTAH containing systems.…”

A quartz crystal microbalance study of the kinetics of interaction of benzotriazole with copper

“…It has also been reported to inhibit the corrosion of iron [26][27][28], cobalt [29], zinc [30], and nickel [28] and to enhance the resistance of tin bronze to oxidation in air [31]. The remarkable inhibiting efficiency of BTAH is attributed to adsorption [32][33][34] and complex formation [34][35][36][37][38], i.e.,…”

Enhancement Corrosion Resistance of (γ-Glycidyloxypropyl)-Silsesquioxane-Titanium Dioxide Films and Its Validation by Gas Molecule Diffusion Coefficients Using Molecular Dynamics (MD) Simulation

“…A f-GSTT network based on organic/inorganic hybrids undergoing extensive cross-linking would lead to the formation of a dense coating with enhanced anticorrosion properties relative to AA, f-GS or f-GSTT. The protection efficiency (P) of the sol-gel coatings on AA could be similarly calculated by the equation [22]:…”