Investigation of the protective efficiency of technological mixture of pyridine bases, its solution in heavy coal solvent and 1-(3,6-diazo-8-amino)-2-(alkyl of tall oil acids)-1,3-diazo- 2-cyclopentene (EM-9) against carbon steel corrosion in chloride media with pH equal to 2 and 4 has been conducted by impedance spectroscopy method. The electrochemical impedance spectroscopy measurements (Solartron) were carried out in the frequency range 60 kHz - 10 mHz at the corrosion potential. Protective effect of the inhibitors (Z,%) was calculated on data of the resistance of charge transfer in anodic reaction. The investigated inhibitors are more effective in the solutions containing H2S or H2S and CO2 together at pH=2. Their protective efficiency is equal to 80 - 85% at the inhibitor concentration equal to 100 mg/l. The obtained values satisfactorily correlate with values of Z calculated on data of the gravimetrical corrosion tests. Protecti ve efficiency of the inhibitors increases with pH decrease.

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Zinc-containing oil-based compositions containing 75 wt. % zinc powder protect carbon steel in the natural conditions of urban atmosphere for a year with the protective efficiency equal to 96 %. More expedient binding is waste motor oil. The insertion of 4 wt. % graphite dust allows to decrease a content of Zn powder in the composition to 60 wt. % without essential alteration of the protective efficiency. The corrosion potential of the steel electrode covered with the oil composition containing 75 wt. % Zn powder or 60 wt. % Zn powder and 4 wt. % graphite dust in the 3 % NaCl solution is near Zn electrode potential. The polarization curves are close to ones of metal zinc. The properties of the above oil compositions were studied by the electrochemical impedance spectroscopy method too. The values of the equivalent scheme parameters satisfactorily correlate with data of the gravimetrical corrosion tests and the results of the polarization measurements and allow to explain the peculiarities of the zinc-containing oil compositions and an influence of their modification with the graphite powder.