Graphite-Fiber Polyimide Composites for Spherical Bearings to 340 deg C (650 deg F)
Abstract
Journal bearings with self-alining spherical elements of graphite-fiber-reinforced - polyimide composites were tested from 24 deg to 340 deg C (75 deg to 650 deg F) at unit loads up 3.5 x 10(exp 7) N/sq m (5000 psi). The journal oscillated in the cylindrical bore of the composite element +/-15 deg at 1 hertz. Outer races and journals were metal hardened to Rockwell C-32 and finished to 10(exp-7)m (4 micro in.) rms. A 45 wt. % graphite-fiber composite gave low friction (0. 08 to 0. 13), low wear, and almost no plastic deformation under any of the test conditions. Composites with 15 and 25 wt.% graphite fiber failed by plastic deformation at 315 deg C (600 deg F) and 3. 5 x 10(exp 7) N/sq m (5000 psi). A composite with 60 wt.% graphite fiber failed by brittle fracture under the same conditions, but had very low friction coefficients (0. 0S to 0. 10) and may be a good bearing material at lighter loads.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1972
- Accession Number
- ADA375464
Entities
People
- Harold E. Sliney
- Robert L. Johnson
Organizations
- National Aeronautics and Space Administration