Microbiological Corrosion in Low Carbon Steels

Abstract

THE MICROBIOLOGICALLY INDUCED CORROSION AFFECTS SEVERAL INDUSTRIES, SUCH AS OIL INDUSTRY WHERE IT IS ESTIMATED THAT 20% TO 0% PIPES FAILURES ARE RELATED WITH MICROORGANISM . THE CHEMICAL REACTIONS GENERATE IONS TRANSFER, THIS VALIDATE THE USE OF ELECTROCHEMICAL TECHNIQUES FOR ITS ANALYSIS. COUPONS SUBMERGED IN A NUTRITIONAL MEDIUM WITH PRESENCE AND ABSENCE OF THREE DIFFERENT MICROORGANISMS DURING TWO PERIODS, 48 HOURS AND 28 DAYS WERE STUDIED. POLARIZATION RESISTANCE (RP) AND ELECTROCHEMICAL IMPEDANCE SPECTROS COPY (EIS) TECHNIQUES WERE APPLIED TO DETERMINE THE CORROSIVITY OF THE SYSTEMS. THE RESULTS SHOW A GREATER CORROSIVE EFFECT OF ABIOTIC SYSTEM, THIS INDICATES A MICROORGANISMS PROTECTION EFFECT TO THE METAL, OPPOSITE TO THE FIRST HYPOTHESIS. THIS RESULT WAS RATIFIED OBSERVING SURFACES COUPONS BY USING SCANNING ELECTRON MICROSCOPY (SEM) TECHNIQUE. A POSSIBLE MECHANISM BASED ON EVANS - TAFEL GRAPH IS PROPOSED TO EXPLAIN INHIBITOR MICROORGANISM EFFECT.