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Studies of Lubricating Materials in VacuumLubricating materials for use in a vacuum environment have been the subject of a series of experimental investigations. Evaporation properties were evaluated for solid polymeric compositions. Friction and wear studies explored the behavior during sliding contact for series of polymeric compositions, binary alloys containing soft film-forming phases, complex alloys with film-forming materials, and a burnished MoS2 film. Friction and wear experiments were conducted at 10(exp-9)mm Hg with a 3/16-inch-radius-hemisphere rider specimen sliding on the flat surface of a rotating 2-1/2-inch-diameter disk specimen with materials that had low rates of evaporation. The influence of fillers in polytetrafluoroethylene (PTFE) on decomposition during vacuum friction studies was determined with a mass spectrometer. A real advantage in reducing decomposition and improving friction wear properties is gained by adding fillers (e.g., copper) that improve thermal conductivity through the composite materials. A polyimide and an epoxy-MoS2 composition material were found to have better friction and wear properties than PTFE compositions. A series of alloys (cast binary as well as more complex alloys) that contained microinclusions of potential film-forming material was studied. These materials replaced the normal surface oxides as they were worn away on sliding contact. Iron sulfide, nickel oxide, and tin are typical film-forming materials employed and were demonstrated to be effective in inhibiting surface welding and reducing friction. A burnished MoS2 film applied to type 440-C stainless steel in argon with a rotating soft wire brush had good endurance properties but somewhat higher friction than commercially available bonded films. An oil film applied to the burnished MoS2 markedly reduced its endurance life.
Document ID
19650025874
Acquisition Source
Headquarters
Document Type
Technical Memorandum (TM)
Authors
Buckley, D. H.
(NASA Lewis Research Center Cleveland, OH, United States)
Johnson, R. L.
(NASA Lewis Research Center Cleveland, OH, United States)
Swikert, M. A.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 2, 2013
Publication Date
January 1, 1964
Subject Category
Nonmetallic Materials
Report/Patent Number
NASA-TM-X-52009
Meeting Information
Meeting: Southwest Research Institute Aerospace Bearing Conference
Location: San Antonio, TX
Country: United States
Start Date: March 25, 1964
End Date: March 27, 1964
Sponsors: Southwest Research Inst.
Accession Number
65N35475
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
WEAR
LUBRICANT
EVAPORATION RATE
FRICTION
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