Attenuated total reflectance spectroscopy of simultaneous processes: Corrosion inhibition of cuprous oxide by benzotriazole

Attenuated total reflectance (ATR) spectroscopy was used to perform in situ studies of the corrosion inhibition of cuprous oxide (Cu2O) by benzotriazole (BTA) in aqueous solution at concentrations from 1 to 20 μM. Because two separate processes occur simultaneously, that of Cu2O corrosion and corrosion inhibition by BTA adsorption, the spectral information was subjected to deconvolution by a conjugate gradient minimization algorithm. Under these conditions, a solution phase concentration of 7-10 μM BTA nearly completely inhibited the corrosion of Cu2O in deionized water. Using a Langmuir adsorption model, this represented only 25% of the maximally covered surface area.