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ChemistryInorganic Chemistry

Mechanisms of Microbially Influenced Corrosion of Stainless Steel and Copper in Marine Systems

Authors: David C. White; Robert J. Palmer; Peter Angell; Cecily A. Flemming; TENNESSEE UNIV KNOXVILLE
Abstract:
Concentric Electrodes (CE) were used to initiate and monitor pitting corrosion of 304 stainless steel by sulfate-reducing bacteria. A current (approx. 10 micro-A/sq cm at the anode) was applied between a small circular anode and a larger surrounding cathode, and microorganisms were introduced into the deaerated seawater medium over the next 48 hours. The applied current was then removed and maintenance of current was recorded. Bacterial metabolism was manipulated with metabolic inhibitors. Experiments were also conducted under aerobic conditions at lower initial current fluxes. The Scanning Vibrating Electrode Microscope (SVEM) was used to congruently map current density and the location microbial cells. The bacterium Oceanospirillum produces a copper- binding exopolymer which has been implicated in copper corrosion. Exopolymer was isolated and partially analyzed. The organism was grown in the presence or absence of Cu(++), and differences in polymer production were examined.

Limitations: APPROVED FOR PUBLIC RELEASE
Description: Final rept. 1 Jan 94-31 May 97
Pages: 5
Report Date: 22 DEC 1998
Contract Number: N00014-94-1-0441
Report Number: A416853
Keywords relating to this report:
*BACTERIA
*BIOLOGICAL CONTAMINATION
*COPPER
*CORROSION INHIBITION
*MICROORGANISMS
*STAINLESS STEEL
AEROBIC PROCESSES
ANODES
CELLS
CIRCULAR
CORROSION
CURRENT DENSITY
ELECTRIC CURRENT
ELECTRODES
METABOLISM
MICROSCOPES
POLYMERS
PRODUCTION
REDUCTION_CHEMISTRY_
SCANNING
SULFATES
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