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Inhibition of carbon steel corrosion by "INCORGAS" compositions in a NACE medium containing hydrogen sulfide and carbon dioxide was studied by electrochemical impedance spectroscopy and linear polarization resistance methods. Contribution of the inhibitor to the total protective effect of the "corrosion product film/inhibitor" system was calculated. Polarization measurements testify that the anodic process is hindered in the presence of the inhibitors. The same conclusion was made from the data of electrochemical impedance spectroscopy.

The universality of inhibitors is understood as their ability to inhibit several types of corrosion attack: hydrogen sulfide and carbon dioxide corrosion, hydrogen diffusion into metal, development of sulfate-reducing and other types of bacteria, negative impact on the mechanical properties of metals. Indicators of universalism of new inhibitor have been studied. Producer of the inhibiting compositions is Limited Liability Company «INCORGAZ» (S-Petersburg, Russia). The efficacy of the inhibitor in the concentration of 25 - 200 mg/L has been studied with respect to carbon steel in a highly mineralized chloride medium (pH= 6) and NACE medium (5 g/L NaCl, 0.25 g/L CH3COOH, pH =3.5) containing H2S (50-400 mg/L) and CO2 (1at) separately and together. The bactericidal properties of the inhibitor were studied with respect to sulfate-reducing bacteria in the Postgate medium. The investigations were carried out by the methods of linear polarization resistance, electrochemical impedance spectroscopy, gravimetry, potentiodynamic polarization. The protective effectiveness of the inhibitor reaches 80% in the presence of CO2 and 90% in hydrogen sulphide environments. The inhibitor repeatedly reduces the number of sulfate-reducing bacteria and the production of biogenic hydrogen sulfide and inhibits the diffusion of hydrogen into steel.

The protective efficiency of a formulation based on low erucic colza oil against carbon steel corrosion in salt solution (0.5 M NaCl), in a thermal moisture chamber and under natural conditions has been studied. The following formulations have been used: (1) colza oil (CO) without inhibiting additives; (2) CO with addition (1-10 wt.%) of synthetic fat acids bottoms (SFAB); and (3) CO with the IFHAN-29A anticorrosion additive (20 wt.%). Corrosion tests and electrochemical measurements have been conducted. Protective CO coatings are not efficient in the presence of chloride ions but provide a high protective efficiency under natural conditions.

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The protective efficiency of a number of nitrogen containing inhibitors against steel hydrosulfide corrosion and their effect on the kinetics of partial electrode reactions have been studied by gravimetrical corrosion tests, polarization resistance and impedance spectroscopy methods. The bactericidal efficiency of the inhibitors with respect to sulfate reducing bacteria (SRB) has been estimated as a function of their nature and concentration.

A method of modeling aggressive atmospheres used for different tests in corrosive environments close as possible to actual full-scale conditions is proposed. The method provides simulation of air atmospheres containing gaseous corrosion stimulants (CS) as microcomponents of air. The content of SCs in such atmospheres (both separately and together) can be set and maintained at an unchanged level within a wide range for as long as desired. The method is based on Henry’s equation characterizing concentration of the gas dissolved in a liquid phase as a function of the gas partial pressure in the equilibrium gas medium with allowance for the solubility of the corrosion stimulants in water in conditions under consideration. The procedure is easy to use and does not require long special training. Samples of corrosion stimulants NH3, CO2, and H2S are considered. Experimental results characterizing the corrosion rate of St3 carbon steel and copper with one or several CS simultaneously present in air atmosphere, as well as data on the efficiency of volatile inhibitors of «IFHAN» series under similar conditions are presented.

The protective efficiency of oil coatings modified by a gun lubricant against copper corrosion in an atmosphere containing sulfur dioxide (up to 5 vol.%) has been studied. The influence of the oil nature, additive concentration, relative humidity (70-100%) and equilibrium SO 2 concentration in the air was investigated. The protective effect of the formulations is up to 90% under particularly corrosive conditions.