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Effects of silver and group II fluoride solid lubricant additions to plasma-sprayed chromium carbide coatings for foil gas bearings to 650 CA 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.
Document ID
19870035062
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Wagner, R. C.
(Case Western Reserve Univ. Cleveland, OH, United States)
Sliney, Harold E.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
August 13, 2013
Publication Date
October 1, 1986
Publication Information
Publication: Lubrication Engineering
Volume: 42
ISSN: 0024-7154
Subject Category
Nonmetallic Materials
Accession Number
87A22336
Funding Number(s)
CONTRACT_GRANT: NCC3-30
Distribution Limits
Public
Copyright
Other

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