This review summarizes the corrosion inhibition of steel materials in acidic media. Numerous corrosion inhibitors for steels in acidic solutions are presented. The emphasis is on HCl solutions, lower-grade steels, and elevated temperatures. This review is also devoted to corrosion inhibitor formulation design - mixtures of corrosion inhibitors with (mainly) surfactants, solvents, and intensifiers to improve the effectiveness of individual compounds at elevated temperatures. The information presented in this review is useful for diverse industrial fields, primarily for the well acidizing procedure, and secondly for other applications where corrosion inhibitors for steel materials are needed.
A study of 2-mercaptobenzoxazole adsorbed on metal from 3 wt.% NaCl solution using electrochemical impedance spectroscopy, potentiodynamic curve, 3D profilometry, and X-ray photoelectron spectroscopy measurements was carried out. The main achievement was the determination of the diffusion coefficient of Cu ions travelling through the solid surface layers, which was estimated to be on the order of 10^(-15)-10^(-14) cm^(2) s^(-1). It was also demonstrated that the Cu(I) MBOH complex is formed on the Cu surface and that the thickness of this surface layer is 1.4 ± 0.4 nm, as determined by the Tougaard method.
Electrochemical and surface analytical techniques were employed to study 2-mercaptobenzothiazole on metal. It was demonstrated that the N atom and exocyclic S atom (not endocyclic S atom) of the 2-mercaptobenzothiazole are involved in molecule adsorption. Moreover, the 2-mercaptobenzothiazole surface layer thickness was estimated to be 1.5 ± 0.5 nm, as determined on the basis of the XPS background spectrum.