Sputtered silver films to improve chromium carbide based solid lubricant coatings for use to 900 C
Thin silver films, 250 to 3500 A thick, were sputtered onto PS200, a plasma sprayed, chromium carbide based solid lubricant coating, to reduce run-in wear and improve tribological properties. The coating contains bonded chromium carbide as the wear resistant base stock with silver and barium fluoride/calcium fluoride eutectic added as low and high temperature lubricants respectively. Potential applications for the PS200 coating are cylinder wall/piston ring lubrication for Stirling engines and foil bearing journal lubrication. In this preliminary program, the silver film overlay thickness was optimized based on tests using a pin-on-disk tribometer. The friction and wear studies were performed in a helium atmosphere at temperatures from 25 to 760 C with a sliding velocity of 2.7 m/s under a 4.9 N load. Films between 1000 and 1500 A provide the best lubrication of the counterface material. The films enrich the sliding surface with lubricant and reduce the initial abrasiveness of the as ground, plasma-sprayed coating surface, thus reducing wear.
- Research Organization:
- National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
- OSTI ID:
- 5369844
- Report Number(s):
- N-88-15885; NASA-TM-100783; E-3955; NAS-1.15:100783; CONF-880581-
- Resource Relation:
- Conference: Annual meeting of the Society of Tribologists and Lubrication Engineers, Cleveland, OH, USA, 8 May 1988
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHROMIUM CARBIDES
TRIBOLOGY
SILVER
BARIUM FLUORIDES
CALCIUM FLUORIDES
COATINGS
FRICTION
SOLID LUBRICANTS
SPUTTERING
STIRLING ENGINES
THIN FILMS
WEAR RESISTANCE
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM HALIDES
CARBIDES
CARBON COMPOUNDS
CHROMIUM COMPOUNDS
ELEMENTS
ENGINES
FILMS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HEAT ENGINES
LUBRICANTS
MECHANICAL PROPERTIES
METALS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
360203* - Ceramics
Cermets
& Refractories- Mechanical Properties