Cathodic Reaction Mechanism of 3Cr Low Alloy Steel Corroded in CO₂-Saturated High Salinity Solutions

摘要

To clarify the cathodic reaction mechanism of 3Cr steel in CO2 environments, two types ofelectrochemical measurements were performed in this study: galvanostatic measurements andpotentiodynamic sweeps. Different cathodic reactions were observed for pH < 3.9 and for pH > 4.7,which differed greatly from that of plain carbon steel. At pH > 4.7, the order of reaction q was zero,- and the direct reduction of HCO3 was the dominating cathodic reaction. At pH < 3.9, q was 0.66, and+ the direct reduction of H was the dominating reaction. At intermediate pH values, a transition wasapparent between reactions.