Effects of silver and group II fluoride solid lubricant additions to plasma-sprayed chromium carbide coatings for foil gas bearings to 650 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 complaint 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 748. Some were coated with the plasma sprayed experimental coating, others with unmodified nickel aluminide/chromium carbide as a baseline for comparison. The additional 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. 7 references.
- Research Organization:
- Lewis Research Center, Cleveland, OH
- OSTI ID:
- 6977800
- Journal Information:
- Lubr. Eng.; (United States), Vol. 42
- Country of Publication:
- United States
- Language:
- English
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Effects of silver and Group II fluorides addition to plasma sprayed chromium carbide high temperature solid lubricant for foil gas bearings to 650/sup 0/C
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Related Subjects
GAS BEARINGS
SOLID LUBRICANTS
CHROMIUM CARBIDES
FLUORIDES
FRICTION
HIGH TEMPERATURE
NICKEL COMPOUNDS
PROTECTIVE COATINGS
SILVER
SURFACE PROPERTIES
TORQUE
WEAR
BEARINGS
CARBIDES
CARBON COMPOUNDS
CHROMIUM COMPOUNDS
COATINGS
ELEMENTS
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
LUBRICANTS
METALS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
320302* - Energy Conservation
Consumption
& Utilization- Industrial & Agricultural Processes- Materials