An Investigation on Pitting Corrosion of 304, 316 and 316L Stainless Steels in 3.5%NaCl Solution and Effect of polyethyleneimine on Pitting Corrosion of These Steels

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Kazazi, Mahdi | 2009

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 40085 (07)
University: Sharif University of Technology
Department: Materials Science and Engineering
Advisor(s): Afshar, Abdollah
Abstract:
In this study, pitting corrosion of 304, 316 and 316L stainless steels in 3.5% NaCl solution at different temperatures (25, 40, and 70°C), were studied by electrochemical methods such as Cyclic Potentiodynamic Polarization, Electrochemical Impedance Spectroscopy and Immersion tests. Also, the effects of different concentrations of polyethyleneimine with two molecular weights (2000 and 60000 g/mol) on pitting corrosion of these steels were investigated. Finally, the adsorption behavior of inhibitors on surface of alloys was investigated by Atomic Force Microscopy (AFM) and Attenuated Total Reflectance Fourier transform spectroscopy (ATR-FTIR). It was found that both inhibitors prevent uniform and pitting corrosion of these steels, However polyethyleneimine with 60000 g/mol molecular weight had higher efficiency than that with 2000 g/mol molecular weight. Also, these inhibitors desorb at temperatures higher than 70°C and can not show good inhibition efficiency.
Keywords:
Pitting Corrosion ; Stainless Steel ; Inhibitor ; Sodium Chloride

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