Effects of silver and group 2 fluorides addition to plasma sprayed chromium carbide high temperature solid lubricant for foil gas bearing to 650 deg C
A new self-lubricating coating composition of nickel aluminide-bonded chromium carbide formulated with silver and Group II fluorides was developed in a research program on high temperature solid lubricants. One of the proposed applications for this new coating composition is as a wide temperature spectrum solid lubricant for compliant foil gas bearings. Friction and wear properties were obtained using a foil gas bearing start/stop apparatus at temperatures from 25 to 650 C. The journals were Inconel 718. Some were coated with the plasma sprayed experimental coating, others with unmodified nickel aluminide/chromium carbide as a baseline for comparison. The addtitional components were provided to assist in achieving low friction over the temperature range of interest. Uncoated, preoxidized Inconel X-750 foil bearings were operated against these surfaces. The foils were subjected to repeated start/stop cycles under a 14-kPa (2-psi) bearing unit loading. Sliding contact occurred during lift-off and coastdown at surface velocities less than 6 m/s (3000 rpm). Testing continued until 9000 start/stop cycles were accumulated or until a rise in starting torque indicated the journal/bearing had failed. Comparison in coating performance as well as discussions of their properties and methods of application are given.
- Research Organization:
- National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
- OSTI ID:
- 5848682
- Report Number(s):
- N-85-14928; NASA-TM-86895; E-2317; CONF-8505124-1
- Resource Relation:
- Conference: Annual meeting of the American Society of Lubrication Engineers, Las Vegas, NV, USA, 6 May 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHROMIUM CARBIDES
WEAR RESISTANCE
FLUORIDES
FLUORINE ADDITIONS
FRICTION
GAS BEARINGS
HIGH TEMPERATURE
NICKEL COMPOUNDS
PROTECTIVE COATINGS
SILVER ADDITIONS
SOLID LUBRICANTS
SPRAYED COATINGS
SURFACE PROPERTIES
WEAR
ALLOYS
BEARINGS
CARBIDES
CARBON COMPOUNDS
CHROMIUM COMPOUNDS
COATINGS
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
LUBRICANTS
MECHANICAL PROPERTIES
SILVER ALLOYS
TRANSITION ELEMENT COMPOUNDS
360203* - Ceramics
Cermets
& Refractories- Mechanical Properties