The term of microbial corrosion is used to describe the corrosion caused by the presence and activity of microorganisms. Microalgae, fungi and bacteria can accelerate the corrosion process or change the mechanism of the corrosion process. One of the most important known organisms is the SRB bacterium, for which various mechanisms have been proposed as to how they affect metals. One of the proposed mechanisms for the effect of this type of bacteria on metal is the theory of biocatalytic reduction of sulfate, which was presented in 2009, and one of the proven applications of this theory is biocathode. In this research, the effect of hydrogenase positive species of SRB bacteria on X70 steel substrate has been investigated in order to provide a solution to reduce this natural problem in industry. For this purpose, by designing a two-chamber biocathode cell for 28 days, the corrosion behavior of X70 steel was investigated by impedance test. The test results showed the formation of biofilm on the metal surface and a significant increase in the amount of load transfer resistance in the process. Using an electron microscope, a layer of corrosion products formed on the metal surface was observed, which confirmed the increase in load transfer resistance in the impedance test. The results of spectrophotometric test showed a decrease in sulfate ion concentration in the biocathode chamber. At the end of the work, the corrosion products formed on the metal surface were examined using XRD tests and the corrosion rate of the metal was eva‎luated.

علي اشرفي، فخرالدين اشرفي زاده

مسعود عطاپور، عبدالمجيد اسلامي