Impact of Sulfate-Reducing Bacteria on Welded Copper-Nickel Seawater Piping Systems

摘要

Field and laboratory experiments were designed to evaluate corrosion in welds and heat-affected zones in copper/nickel seawater piping systems exposed to estuarine water and seawater. The localized corrosion was shown to be due to the following sequence of events: 1) metal segregation during heating processes; 2) settlement of sulfide-producing bacteria in welds; 3) sulfide derivatization; 4) disruption of the surface films by turbulence and 5) formation of adjacent cathodic and anodic areas. Metallic segregation in welded areas was detected by an X-ray spectrometer before the welds were exposed to estuarine water. Within the crevices, occlusions, and surface irregularities of butt and socket welds unique environments of microbial colonization existed. Reprints. (jes)