Effect of bacterial biofilms on carbon steel pit propagation in phosphate containing medium

Conference · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5883319

Franklin, M J ^[1]; White, D C ^[2]; Isaacs, H S ^[3]

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1. Tennessee Univ., Knoxville, TN (USA). Dept. of Microbiology Tennessee Univ., Knoxville, TN (USA). Inst. for Applied Microbiology
2. Tennessee Univ., Knoxville, TN (USA). Dept. of Microbiology Tennessee Univ., Knoxville, TN (USA). Inst. for Applied Microbiology Oak Ridge National Lab., TN (USA)
3. Brookhaven National Lab., Upton, NY (USA)

Chemical corrosion inhibitors are commonly added to aqueous systems to minimize the oxidation of steel. The efficacy of certain inhibitors may be reduced by bacteria. In the present study, the effect of microbial biofilms on carbon steel corrosion inhibition by phosphate was analyzed, using the scanning vibrating electrode technique (SVET) and monitoring of open circuit potential. Previous results have shown that in sterile medium containing 0.2 mM phosphate, as well as 1.0 mM chloride and 0.2 mM sulfate, carbon steel samples showed small anodic sites which subsequently became inactive. Whereas, in the presence of bacteria pits failed to become inactive and continued to propagate. In the present study, comparisons between viable bacteria and formaldehyde fixed bacteria on the pit propagation was analyzed. The results indicated that biofilms containing viable bacteria and fixed bacteria could cause pits to propagate. The time required for pit propagation was dependent on the concentration of bacteria as well as the viability of the bacteria. The results indicate that bacterial biofilms can cause pits, initiated by chemical corrosion, to continue to propagate either by reducing the efficacy of phosphate as a corrosion inhibitor or by maintaining the aggressive environment within pits. 14 refs., 4 figs., 1 tab.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: DOD; DOE; EPRI; TNU; Department of Defense, Washington, DC (USA); USDOE, Washington, DC (USA); Electric Power Research Inst., Palo Alto, CA (USA); Tennessee Univ., Knoxville, TN (USA)
• DOE Contract Number: AC05-84OR21400; AC02-76CH00016
• OSTI ID: 5883319
• Report Number(s): CONF-9010138-2; ON: DE91010806; CNN: N00014-87-K0012; RP-3015-1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360604* -- Materials-- Corrosion
Erosion
& Degradation
ALLOYS
CARBON STEELS
CHEMICAL REACTIONS
CORROSION
CORROSIVE EFFECTS
INHIBITION
IRON ALLOYS
IRON BASE ALLOYS
MICROORGANISMS
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PITTING CORROSION
STEELS
VIABILITY