Electrochemical study of crevice environment in high-temperature water -- Corrosion potential and pH measurement
- Toshiba Corp., Yokohama (Japan)
High-temperature pH was measured with zirconia membrane electrode with crevice-forming sheath in high purity water. The crevice pH was substantially lower than that of bulk water. Corrosion potential was measured in crevice and on free surface in high-temperature, high-purity water with Type 304 stainless steel (SS), Alloy 600 and their Cr-depleted model alloys. The crevice corrosion potential was 300 to 400 mV lower than that of free surface. The coupling current was observed from free surface cathode to crevice anode. The surface films formed in crevice and on free surface were characterized with Auger electron spectroscopy and laser Raman spectroscopy. The crevice surface films of Type 304 SS and Alloy 600 were thinner than free surface, but those of Cr-depleted model alloys were thicker than free surface. The most prominent compound was NiFe{sub 2}O{sub 4} in the surface film formed both in crevice and on free surface. The crystallinity and the content of other compounds such as Fe{sub 3}O{sub 4} or NiO were different between crevice and free surface.
- OSTI ID:
- 70144
- Report Number(s):
- CONF-940222--
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
CHEMICAL COMPOSITION
CORROSION RESISTANT ALLOYS
CREVICE CORROSION
ELECTROCHEMISTRY
EXPERIMENTAL DATA
INCONEL 600
IRON OXIDES
NICKEL OXIDES
PASSIVATION
PH VALUE
PHASE DIAGRAMS
PROTECTIVE COATINGS
STAINLESS STEEL-304
SURFACE POTENTIAL
WATER COOLED REACTORS