Electrochemical and microelectrode studies of stainless steel ennoblement

Book · Fri Dec 01 04:00:00 EST 1995

OSTI ID:128677

Dickinson, W; Lewandowski, Z ^[1]

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1. Montana State Univ., Bozeman, MT (United States). Center for Biofilm Engineering

Ennobled open-circuit potential (E{sub corr}) for stainless steel exposed to fresh river water is investigated using microelectrodes to measure dissolved oxygen, hydrogen peroxide, and local E{sub corr} within the biofilm. Results indicate the biofilm is uniformly aerobic and does not contain elevated levels of cathodic depolarizers. Development of ennobled potential is observed to correlate with E{sub corr} near beginning of exposure and occurs on surfaces exhibiting as little as 20% biofilm coverage. Galvanostatic measurements of coupon capacitance reveal a strong correlation between capacitance and E{sub corr} as the latter increases during microbial colonization. Cathodic reduction measurements indicate that an increase in surface Fe{sub 2}O{sub 3} content occurs for stainless steel samples that develop ennobled potential. Results suggest an ennoblement mechanism involving modifications of the metal-oxide surface. A new interpretation of cathodic polarization behavior for ennobled stainless steel is given based on proposed changes in cathodic reaction rates that occur on the microbially modified oxide surface during polarization.

• OSTI ID: 128677
• Report Number(s): CONF-950304--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BIOLOGICAL FOULING
CAPACITANCE
DEPOLARIZATION
ELECTRIC POTENTIAL
EXPERIMENTAL DATA
FILMS
HYDROGEN PEROXIDE
MICROSCOPY
OXIDES
OXYGEN
STAINLESS STEEL-316L
TIME DEPENDENCE