Corrosion behaviour of X60 steel in the presence of sulphate-reducing bacteria (SRB) and iron-reducing bacteria (IRB) in seawater

Abstract

ABSTRACT In this study, the corrosion behavior of X60 was investigated in the presence of a mixed culture of sulfate-reducing bacteria (SRB) and iron-reducing bacteria (IRB) via weight loss, electrochemical impedance spectroscopy (EIS), and Tafel polarization techniques. Moreover, field emission scanning electron microscope (FESEM) images and X-ray diffraction spectrometry (XRD) were used to study the morphological changes of the surface of X60 and the composition of corrosion products after exposing X60 to the abiotic and biotic systems. EIS result confirmed the occurrence of microbial corrosion in the presence of SRB and IRB. In the exposed coupon to the mixture of bacteria, the result illustrated that the existence of IRB promoted the SRB growth, so corrosion rate increased compared to the exposed coupon to SRB and IRB, respectively. The mixture of SRB and IRB showed a synergistic effect and enhanced the pitting corrosion on the surface of X60.