An in situ FT-IR evaluation of candidate organic corrosion inhibitors for carbon steel in contact with alkaline aqueous solutions

The influence of some organic additives on the anodic behaviour of a carbon steel electrode in contact with alkaline aqueous solutions was studied by in situ Fourier transform infrared (FT-IR) spectroscopy. FT-IR spectroscopy allows to obtain information at the molecular level regarding the metal-electrolyte interface. The following molecules have been considered: (i) benzyldimethylphenyl-ammonium chloride (BDMPAC), (ii) glutamic acid, (iii) triethylenetetramine (TETA), (iv) sodium tartrate and (v) sodium benzoate. Potential-dependent spectra have been recorded for the different investigated systems. Quantitative information about the formation kinetics of corrosion products was derived by numerical analysis of the peak area as a function of the applied potential for the different systems investigated.