The influence of sulfide inclusions on the initiation of pits in Fe-29Ni-17Co
Kovar sheet and rod samples were tested in the as-received (R/sub B/80 and R/sub B/95, respectively) condition. Pitting tests were conducted on three sheet orientations: face, long-transverse (side), and short-transverse (end) and on two rod orientations: cross section (end) and length. Samples were prepared for testing by grinding and chemically cleaning all faces, spot-welding a Kovar wire to the back, and mounting in Maraglas resin. The exposed face was ground with 600-grit SiC paper and rinsed in deionized water immediately before testing. The grinding scratches were aligned in the rolling direction of the sheet and the drawing direction of the rod length. All tests were conducted in a room temperature 0.5 M NaCI electrolyte adjusted to pH 10 by the addition of NaOH. Polarization of Kovar in nonalkaline 0.5 M NaCI did not yield a sharp pitting potential because of the lack of a stable passive potential region. The electrolyte was purged with N/sub 2/ during testing and for a minimum of 4 h before testing. Potentiodynamic tests were conducted from the open circuit potential, following 15-min immersion, at a potential scan rate of 6 mV/min. Critical pitting potentials are reported as the average of six measurements.
- Research Organization:
- Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5898197
- Journal Information:
- Corrosion (Houston); (United States), Vol. 42:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
KOVAR
PITTING CORROSION
AMBIENT TEMPERATURE
ELECTROLYTES
INCLUSIONS
MATERIALS TESTING
PH VALUE
RODS
SHEETS
SODIUM CHLORIDES
SODIUM HYDROXIDES
SULFIDES
ALKALI METAL COMPOUNDS
ALLOYS
CHALCOGENIDES
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
COBALT ALLOYS
CORROSION
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
HYDROXIDES
IRON ALLOYS
IRON BASE ALLOYS
MANGANESE ADDITIONS
MANGANESE ALLOYS
NICKEL ALLOYS
OXYGEN COMPOUNDS
SODIUM COMPOUNDS
SULFUR COMPOUNDS
TESTING
360105* - Metals & Alloys- Corrosion & Erosion