CORROSION AND INHIBITION MECHANISM OF IRON SURFACE BASED ON OXYGEN REDUCTION REACTION (ORR) BY NATURAL PLANT EXTRACT AS A GREEN CORROSION INHIBITOR

• Main Author: Akrom, Muhamad
• Format: Dissertations
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/74657
• Institution: Institut Teknologi Bandung

The mechanism of corrosion on the iron surface and the mechanism of its corrosion inhibition by inhibitor molecules have been successfully investigated by evaluating the performance of the oxygen reduction reaction (ORR) process using a combination of density functional theory (DFT) calculations and microkinetic simulations. We found that ORR activity could only be initiated when the iron surface was covered by O atoms until the monolayer coverage was almost complete. We found that the first stage of the corrosion process on the iron surface was initiated by the passivation of the clean surface by dissociated O2 molecules without starting the ORR (high overpotential, low turnover potential (TOF)) process. The exact level of ORR was only observed when the iron surface was covered by O atoms until the monolayer coverage was almost complete, indicating that the corrosion process also started at such surface conditions (low overpotential, high TOF). We found that adsorbed inhibitors on the iron surface limit the adsorption sites for the ORR intermediate and attenuate these interactions with the iron surface. This condition greatly inhibits the ORR process on the iron surface and causes very low ORR levels (high overpotential, low TOF). This mechanism explains why the inhibitor molecules can be successfully used as green corrosion inhibitors on ferrous surfaces.