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The Effect of Stress and TiC Coated Balls on Lubricant Lifetimes Using a Vacuum Ball-on-Plate Rolling Contact TribometerA vacuum ball-on-plate rolling contact tribometer was used to determine the relative lifetimes of a perfluoropolyether (Krytox 143 AC) on 440C stainless steel. The effect of mean Hertzian stresses (0.75, 1.0, 1.5 and 2.0 GPa) and the use of TiC coated balls on lubricant lifetime was studied. Other conditions included: approximately 100 rpm, approximately 50 micrograms of lubricant, an initial vacuum level of less than 1.0 x 1O(exp -8) Torr, and room temperature (approximately 23 C). increasing the mean Hertzian stress from 0.75 to 2.0 GPa results in an exponential decrease in lubricant lifetime for both material combinations. However. substituting a TiC ball for the 440C ball quadrupled lifetime at low stress levels (0.75 and 1.0 GPa) and doubled life at higher stresses (1.5 and 2.0 GPa). The reduced reactivity of the TiC surface with the PFPE lubricant is considered to be the reason for this enhancement. Decreasing lifetime with increasing stress levels correlated well with energy dissipation calculations.
Document ID
19990032034
Acquisition Source
Glenn Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Jones, William R., Jr.
(NASA Glenn Research Center Cleveland, OH United States)
Jansen, Mark J.
(AYT Corp. Brook Park, OH United States)
Helmick, Larry H.
(Cedarville Coll. OH United States)
Nguyen, QuynhGiao
(AYT Corp. Brook Park, OH United States)
Wheeler, Donald R.
(NASA Glenn Research Center Cleveland, OH United States)
Voving, Hans J.
(Centre Suisse d'Electronique et de Microtechnique S..A. Neuchatel, Switzerland)
Date Acquired
September 6, 2013
Publication Date
March 1, 1999
Subject Category
Nonmetallic Materials
Report/Patent Number
NASA/TM-1999-209055
E-11591
NAS 1.15:209055
Meeting Information
Meeting: Aerospace Mechanisms
Location: Pasadena, CA
Country: United States
Start Date: May 19, 1999
End Date: May 21, 1999
Sponsors: Lockheed Martin Corp., NASA Glenn Research Center
Funding Number(s)
PROJECT: RTOP 615-63-00
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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