Potential of 5-methyl 1-H benzotriazole to suppress the dissolution of α-aluminum bronze in sulfide-polluted salt water

• MBT is an excellent mixed corrosion inhibitor for bronze.
• There is a competitive adsorption between MBT and sulfide ions to adsorb on bronze surface.
• The adsorption of MBT is spontaneous and follows Langmuir model.
• CPE decreases significantly with the increasing MBT concentration.

This work investigates the inhibition effect of 5-methyl 1-H benzotriazole (MBT) on the dissolution behavior of α-aluminum bronze in clean and sulfide-polluted salt water using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM) and scanning electron microscopy (SEM) techniques. The inhibition efficiency increases with the increasing MBT concentration and decreases with the increasing temperature. The adsorption process of MBT is spontaneous and follows Langmuir adsorption isotherm model. MBT possesses excellent inhibiting effect for the corrosion of α-Al-bronze, which acts as a mixed type inhibitor. Thermodynamic and kinetic parameters for the adsorption process were determined. The presence of sulfide ions (2 ppm) decreases the inhibition efficiency of MBT against the corrosion of Al-bronze alloy in chloride solutions from 94.7% to 89% as also confirmed via SEM images. The results obtained from the different techniques were in good agreement, which prove the validity of these tools in the measurements of the tested inhibitor.