Accession Number : ADA305067

Title :   Lubricating and Wear Mechanisms for a Hemisphere Sliding on Polyimide-Bonded Graphite Fluoride Film.

Descriptive Note : Technical paper,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CEN TER

Personal Author(s) : Fusaro, Robert L.

PDF Url : ADA305067

Report Date : AUG 1979

Pagination or Media Count : 29

Abstract : Friction, wear life, rider wear, and film wear for a 440C high-temperature-stainless-steel, hemispherically tipped rider sliding against polyimide-bonded graphite fluoride films were evaluated in a moist-air atmosphere at 25 deg C. Optical microscope and surface profilometry observations were made at various sliding intervals to determine how film thickness affected the lubricating and failure mechanisms of the films. Two lubrication regimes operated for the same load. In the first, the film supported the load and the lubricating mechanism consisted of the shear (plastic flow) of a thin layer of the lubricant between the metallic rider and the film surface. In the second, the film did not support the load (it was worn away) and the lubricating mechanism consisted of the shear of very thin lubricant films between flat areas generated on the rider and on sandblasted metallic asperities in the film wear track. Lubricant was supplied from the valleys between the asperities or from the sides of the wear track. With thicker films wear life increased since a greater lubricant supply was available from the sides of the wear track. jg p29

Descriptors :   *GRAPHITE, *WEAR, *FLUORIDES, *HEMISPHERES, *SLIDING, *LUBRICATING FILMS, *POLYIMIDE PLASTICS, METALS, OPTICAL EQUIPMENT, THICKNESS, AIR, LAYERS, HIGH TEMPERATURE, THIN FILMS, FAILURE, STAINLESS STEEL, PROFILOMETERS, SURFACES, MOISTURE, MICROSCOPES, FRICTION, LUBRICANTS, PLASTIC FLOW, INTERVALS.

Subject Categories : Lubricants and Hydraulic Fluids
      Inorganic Chemistry
      Polymer Chemistry
      Coatings, Colorants and Finishes
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE