Fundamental Studies on the Corrosion Behavior of Weldments in Marine MicrobialEnvironments

摘要

Weldments representative of a range of marine structural materials, in bothcreviced and non-creviced conditions, were exposed to a natural marine environment at a University of Delaware site on the Delaware Bay, Lewes, Delaware. Companion laboratory control tests were conducted at the University of Tennessee in 0.2 micrometer filtered Delaware Bay water and in synthetic seawater. The weldments studied were: 304L, 316L and AL-6XN stainless steels; HY-80 and HSLA-80 low-alloy steels; Alloy 400 Ni-Cu alloy; 90-10 Cu-Ni alloy; 5086 aluminum alloy; and unalloyed titanium. Open-circuit potentials (OCPs) and corrosion rates were evaluated for all tests. In the non-creviced condition, ennoblement of the OCP, relative to the laboratory control tests, occurred for all weldments. Clearly, a microbial effect at the Delaware Bay site was responsible for this ennoblement. For the creviced condition, in most cases, the OCPs in the natural microbial environment were less than those in the laboratory