Effect of Corrosion Inhibition on the Mitigation of Preferential Weld Corrosion in Seawater Transport Systems

摘要

The scanning electrochemical microscope (SECM) is being used to investigate the effect of corrosion inhibition in the mitigation of preferential weld corrosion (PWC). Using the in-situ electrochemical methodology combined with the high spatial resolution at a microscopic level capability of the SECM to assess corrosion current distribution across the exposed surface of PWC susceptible welds in an environment simulating a seawater transport. The data from the SECM evaluation of PWC affected surface, strongly suggests that the anodic current distribution between the heat-affected zones (HAZ), weld and base metal is affected by the concentration of corrosion inhibition present. The results obtained indicate that under dosage of corrosion inhibition, at least in a seawater system, can cause localized corrosion attack in PWC susceptible HAZ.