Study of the Influence of Corrosion Inhibitors on the Corrosion Mechanism Promoted by the Bacteria Growth of Desulfovibrio Vulgaris Using Electrochemical Noise

The use of corrosion inhibitors on systems related to the transport of hydrocarbon products is a common practice in the petrochemical industry. The efficiency of this chemical reagents is affected in many ways by a lot of variables, one of them is the presence of microorganisms. The presence of these microorganisms can modify the metallic surface, the corrosion media, or cause the formation of corrosion products and layers of chemical substances on the surface. In the present work, the electrochemical parameters Localization Index (LI) and Noise Resistance (Rn) obtained from the Electrochemical Noise (EN) technique were used to analyze the effect of the growth of the Sulphide-Reducer Bacteria (SRB) Desulfovibro vulgaris on the efficiency of two different corrosion inhibitors on AISI 1018 low carbon steel: imidazoline and sodium nitrite (NaNO₂). The results show that on each phase of the bacteria growth with the presence of the corrosion inhibitors, the values for the Localization Index and Noise Resistance present significative variations. These variations define the corrosion processes (localized corrosion, mixed corrosion and generalized corrosion) depending on the particular phase of the bacteria growth.