The synergistic inhibition of the cold rolled steel Corrosion in 0.5 M sulfuric acid by the mixture of OP and bromide ion

The synergistic inhibitive effect of the mixture of OP and NaBr on the corrosion of cold rolled steel in 0.5 M sulfuric acid has been investigated using weight loss and polarization method. The results reveal that corrosion of cold rolled steel has been efficiently inhibited by OP in the presence of NaBr in sulfuric acid, and inhibition efficiency increases with increasing concentration of OP at a constant temperature. A synergistic effect has been observed for OP with NaBr at all investigated temperatures (except 30 °C). The polarization curves show that the mixture of OP and NaBr is a cathodic inhibitor. The experimental results suggest that the presence of bromide ion in the solution stabilizes the adsorption of OP molecules on the metal surface and improves the inhibition efficiency of OP. Langmuir adsorption isotherm equation is obeyed at all the temperatures studied. The results obtained from weight loss and polarization method are in good agreement. The present study is important for the practical use of surfactant as corrosion inhibitor for steel in acidic media.