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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.

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The protective efficacy of volatile inhibitors (VCI) IFKhAN-8 (an amino alcohol), IFHAN-112 (a mixture inhibitor based on benzotriazole), IFKhAN-114 (a non-equimolar mixture of a polyamine and a weak organic acid) and IFKhAN-118 (a dimethylbenzylamine salt) was studied in atmospheric corrosion of M2 copper (99.7 wt.%) and L62 two-phase brass (22.5 wt.% Zn and 67.7 wt% Cu) in the presence of corrosion stimulators (CS): CO 2 (0.2-0.6 vol.%), NH 3 (20-60 mg/m 3 ) and H 2 S (10-30 mg/m 3 ), either separately or in combination.In an uninhibited atmosphere with 0.6 vol.% CO 2 + 60 mg/m 3 NH 3 (three times higher than the normally permissible CS concentrations) with a relative humidity of 100%, corrosion of copper and brass has a pronounced local character. In addition, there is a darkening of a significant fraction of the surface of metals (CuO film). The protective efficiency (Z%) of in relation to the total corrosion is 75% (brass) and 85% (Cu); 82% (brass) and 79% (Cu) and 89% (brass) and 85% (Cu), respectively. In the atmosphere with CO 2 (0.6 vol.%) + H 2 S (30 mg/m 3 ) or H 2 S (30 mg/m 3 ) + NH 3 (60 mg/m 3 ) in the presence of IFKhAN-114, Z is 75% (brass, copper). With the other inhibitors being studied in the atmosphere, Z is reduced to 13% or even stimulation of corrosion is observed (CO 2 + H 2 S).In the presence of all the three corrosion stimulators, IFHAN-114 with a protective effect of 96% (brass) and 95% (copper) is again the most effective. This VCI hinders the anodic reaction of ionization of the metals both at the initial stage of exposure in the medium and after 96 hours of exposure. IFHAN-114 inhibits the anodic process in the presence of (NH 4 ) 2 S or (NH 4 ) 2 CO 3 salts as reaction products of H 2 S or H 2 CO 3 with NH 3 in the solution, which occurs in the surface phase film of moisture. At the same time, this Int. J. Corros. Scale Inhib., 2018, 7, no. 3, 331-339 332 volatile corrosion inhibitor completely prevents local damage to brass and copper under all conditions studied.

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