Evidence of biogenic corrosion of titanium after exposure to a continuous culture of thiobacillus ferrooxidans grown in thiosulfate medium
Experiments were undertaken to evaluate extreme conditions under which candidate materials intended for use in a proposed nuclear waste repository might be susceptible to corrosion by endogenous microorganisms. Thiobucillus ferrooxidans, a sulfur-oxidizing bacterium, was grown in continuous culture using thiosulfate as an energy source; thiosulfate is oxidized to sulfate as a metabolic endproduct by this organism. Culture conditions were optimized to produce a high-density, metabolically active culture throughout a period of long term incubation in the presence of Alloy 22 (a high nickel-based alloy) and Titanium grade 7 (Tigr7) material coupons. After seven months incubation under these conditions, material coupons were withdrawn and analyzed by high resolution microscopy and energy dispersive x-ray analyses. Alloy 22 coupons showed no detectable signs of corrosion. Tigr7, however, demonstrated distinct roughening of the coupon surface, and [presumably solubilized and precipitated] titanium was detected on Alloy 22 coupons incubated in the same T. ferrooxiduns culture vessel. Control coupons of these materials incubated in sterile thiosulfate medium did not demonstrate any signs of corrosion, thus showing that observed corrosive effects were due to the T. ferrooxidans metabolic activities. T. ferrooxidans intermediates of thiosulfate oxidation or sulfate may have caused the corrosive effects observed on Tigr7.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15006116
- Report Number(s):
- UCRL-JC-141910; TRN: US0400423
- Resource Relation:
- Conference: Corrosion 2001, A National Association of Corrosion Engineers Odyssey, Houston, TX (US), 03/11/2001--03/16/2001; Other Information: PBD: 7 Dec 2000
- Country of Publication:
- United States
- Language:
- English
Similar Records
Role of a ferric ion-reducing system in sulfur oxidation of Thiobacillus ferrooxidans
The effect of acidophilic heterotrophic bacteria on the leaching of cobalt by Thiobacillus ferrooxidans
Related Subjects
54 ENVIRONMENTAL SCIENCES
ALLOYS
CONTINUOUS CULTURE
CORROSION
CORROSIVE EFFECTS
ENERGY SOURCES
ENGINEERS
INCUBATION
MICROORGANISMS
MICROSCOPY
OXIDATION
RADIOACTIVE WASTES
RESOLUTION
SULFATES
THIOSULFATES
TITANIUM