Organic inhibitors of steel hydrogenation (analytical review of publications)

Issue 24(3) 2019
Pages 66-71

S.A. Teryusheva, Department of Chemistry, Baltic State Academy Fishing Fields «Kaliningrad State Technical», Kaliningrad, Russian Federation


Keywords: sulphate-reducing bacteria, organic compound, structure, inhibitor, corrosion, hydrogenation of steel

http://www.doi.org/10.31615/j.corros.prot.2019.93.3-8

 

Analysis of publications for the study of organic inhibitors of hydrogenation of steel in environments with sulphate-reducing bacteria is given. The following statements are showed in the paper. The establishment of a relationship was demonstrated between the structure of organic compounds with their effectiveness of inhibiting the hydrogenation of steel. Investigation was represented of the relationship of the structure of organic compounds and the composition of their molecules with the effectiveness of their action on the absorption by metal, primarily iron and its alloys, of hydrogen cathodically released on its surface during corrosion with hydrogen depolarization or under conditions of cathode polarization. The effect of organic compounds (phenols and quinones) was demonstrated on the process of metal hydrogenation. Suppression of the life activity of sulphate-reducing bacteria was shown for prevention of “sulphide cracking”, i.e., hydrogen embrittlement of steel when hydrogen sulfide promotes absorption of hydrogen by steel during its corrosion. An ideal case would be the combination of the properties of a hydrogen sulfide corrosion inhibitor, a bactericide and a hydrogenation inhibitor in one organic compound. According to the effectiveness of the action inhibiting the process of hydrogenation the phenols are arranged in the following row: phenol › pyrocatechin › hydroquinone › pyrogallol. It is known the derivatives of quinones as inhibitors hydrogenation of steel. At cathodic polarization, the protection against hydrogenation by a layer of admolecules of organic compounds reaches rarely 100%, the best inhibitors give 90 ... 98%. In particular small amounts of organic compounds give the greatest effect of anti-hydrogenation, approaching to 100% is difficult to achieve, the large concentrations of organic compounds in solution are required which sometimes leads to the formation of polymolecular layers of inhibitor on the cathode.