Inhibition Effect And Mechanism Of Volatile Corrosion Inhibitor On Metal Corrosion Under Thin Electrolyte Layer

The purpose of this study was to investigate the inhibition effect and mechanism of benzotriazole (BTA) and dicyclohexylamine nitrite (DICHAN) on the metal corrosion under adsorbed thin electrolyte layer (ATEL). We designed an experimental device to study the inhibition efficiency and investigate the influence of temperature, relative humidity (RH) and chloride ion concentration on BTA adsorption, and the influence of temperature, exposure time and compounded with other corrosion inhibitors on DICHAN adsorption.The inhibition efficiency was investigated using potentiodynamic and electrochemical impedance spectrum measurements (EIS). The surface was characterized by scanning electron microscopy (SEM), in situ atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance-Fourier transformed infrared (ATR-FTIR).For copper, the results show that BTA mainly suppresses the anodic corrosion reaction and has strong inhibition effect on copper corrosion, the results indicate that the good inhibition of BTA on the early stage of copper corrosion is attributed to its quick interaction with Cu(0) via N atom to form a thin protective film at non-corroded areas and interaction with Cu(I) via N atom to form thick polymeric [Cu+BTA-]n complex on Cu2O substrate at defect sites. The cathodic polarization current densities increase with the increase of RH, Cl ion concentrations. The effect of temperature on BTA adsorption is complicated, the optimum temperature conditions is50℃For carbon steel, results show that DICHAN is mixed type inhibitor and it interacts with the steel surface by chemisorption, elevate temperature and compound with dithiooxamide or BTA both can slightly increase the inhibition efficiency.