Electrochemical Behavior of Stainless Steel under High-Temperature and High-Pressure Methanol Solution Containing Oxygen and Chloride Ions

• Published in: Journal of materials science and engineering. B 2011-12, Vol.1 (7), p.861-870
• Main Authors: Shintani, D, Ishida, T, Matsuo, Y, Sugie, Y
• Format: Article
• Language: chi ; eng
• Subjects: 316L不锈钢; Aerated; Anodic polarization; Austenitic stainless steels; Corrosion; Electrochemical impedance spectroscopy; Heat resistant steels; Methyl alcohol; Moisture content; Pitting (corrosion); Stainless steels; 氧气; 水分含量; 甲醇溶液; 电化学行为; 离子对; 阳极极化曲线; 高压
• ISSN: 2161-6221

The effect of oxygen and water in a methanol solution containing 0.42 wt% LiCI on the corrosion behavior of Type 316L stainless steel was evaluated by anodic polarization and electrochemical impedance spectroscopy （EIS） at 423 K and 473 K. The Ecorr values in an aerated methanol solution decreased with immersion time and became almost the same as that observed in a deaerated methanol solution after 5 h. The dissolved oxygen molecules temporarily improved the corrosion resistance, judging from the increase in Ea （anodic dissolution potential）. This effect of oxygen molecules was not observed with the immersion time, consequently the anodic polarization curve became almost similar to that obtained in the absence of them. While the localized tarnish was observed in the aerated methanol solution with lower water contents, many pits formed when the water content increased. At 423 K, a corrosive effect of oxygen in the methanol solution was exhibited in the presence of water and pitting corrosion and autocatalytic reaction were observed. On the other hand, no corrosion occurred at 473 K, regardless of the oxygen and water concentrations.