Surface segregation of sulfur during oscillatory pin-on-plate wear studies of precious metal electrical contact alloys: I. Friction and electrical contact resistance
An oscillatory pin-on-plate experimental configuration was used to investigate friction and electrical contact resistance phenomena of a gold base (ASTM B541) and a palladium base (ASTM B540) alloy couple. Effects which could be attributed to surface segregation were noted. Measurements were made in controlled environments of dry helium, dry carbon dioxide and dry air at atmospheric pressure. A load cell was used to measure the friction force continuously. No lubrication was employed. A U-shaped pin was used with electrical connections to measure electrical contact resistance for both forward and reverse direct currents. Friction coefficients were initially high but decreased to a steady value of approximately 0.2 as the number of oscillatory cycles increased for dry carbon dioxide and dry air. The friction results for dry helium were much more erratic. Friction coefficients are much less sensitive to the nature of the contact interface than is electrical contact resistance. The electrical contact resistance always had initial values of 1 to 10 milliohms, but it tended to increase by up to three orders of magnitude in a nonreproduceable manner for all three gases. Sharp fluctuations in electrical contact resistance were common. Electrical polarity was reversed, but due to the large variability in contact resistance no effect was identified. The results are interpreted in the following paper as arising from wear segregation of sulfur to the contact interface during the oscillatory cycles.
- Research Organization:
- Syracuse Univ., NY (USA); Sandia National Labs., Albuquerque, NM (USA); Sandia National Labs., Livermore, CA (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6919167
- Report Number(s):
- SAND-83-2151C; CONF-840935-1-Pt.1; ON: DE84006962
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360104* -- Metals & Alloys-- Physical Properties
42 ENGINEERING
420800 -- Engineering-- Electronic Circuits & Devices-- (-1989)
AIR
ALLOYS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
ELECTRIC CONDUCTIVITY
ELECTRIC CONTACTS
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
ELEMENTS
EQUIPMENT
FLUIDS
FRICTION
GASES
GOLD ALLOYS
HELIUM
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PALLADIUM ALLOYS
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
RARE GASES
SEGREGATION
SURFACES