The effect of Variamine Blue B on brass corrosion in NaCl solution

AbstractThe effect of Variamine Blue B (4-Amino-4′-Methoxydiphenylamine-Diazonium Chloride, VBB) on the corrosion of Cu–35Zn alloy (brass) in 3.5% NaCl medium was studied at different concentrations and temperatures. For this purpose, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques were used as electrochemical techniques. Scanning electron microscopy (SEM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was used as optical techniques to investigate the brass surface. According to experimental results, inhibitor effectiveness increased with increasing temperature and VBB reduced the corrosion rate by acting as a mixed type inhibitor. The activation energy (Ea) of the dissolution process and the standard free energy values ΔGoads of the adsorption process showed that chemical interactions also had a minor contribution to the adsorption of VBB on brass surface while physical interactions had a major one. Electrochemical and optical results revealed that VBB molecules held persistently on brass surface even after 120h. The existence of VBB on brass surface was verified experimentally by ex-situ ATR-FTIR spectroelectrochemical measurement