PROTECTION OF STEEL FROM CORROSION IN ACIDIC MEDIA AT ELEVATED TEMPERATURES BY "SOLING" SERIES INHIBITORS

The work presents the results of the study of a number of inhibitory compositions of the "Soling" series based on acetylenic alcohols and their mixtures with nitrogen-containing compounds of various types in a hydrochloric and sulfuric acid solutions at temperatures 20-60 degrees C. Electrochemical studies were performed on mild steel St3. Polarization curves were obtained in a three-electrode cell, using the SOLARTRON 1280 C electrochemical measuring complex. The protective compositions were studied: Soling IK-1 on the basis of unsaturated alcohol in a mixture with sulfur-containing amide in an aqueous medium; Soling IK-2 on the basis of unsaturated alcohol with additions of quaternary ammonium salt and complexone; Soling IK-3 on the basis of unsaturated alcohol in the system of organic solvents, as well as Soling IK-4(A) on the basis of a high-molecular nitrogen-containing surfactant (molecular weight from 300 to 400) with additions of unsaturated alcohol in a system of organic solvents and Soling IK-4(B) based on a high-molecular nitrogen-containing surfactant with a molecular weight of up to 300. It has been obtained that Soling IK-2, IK-4(A) and IK-4(B) compositions have a high protective effect throughout the temperature range, which indicates the stability of the adsorption layers of the inhibitor with increasing temperature. Compositions IK-1 and IK-3 have less protective effect, but in general, the temperature increase does not have a strong negative effect on the magnitude of the protective effect. The stability of the compositions under study is explained by the presence in their composition of unsaturated alcohols showing high protective characteristics at elevated temperatures. Based on the results obtained, the effective activation energies of the corrosion process have been calculated.