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Volatility and Wear Characteristics of a Variety of Liquid Lubricants for Space ApplicationsThe vapor pressures and near characteristics are critical properties for liquid lubricants to assure long-term reliability and performance in space applications. Vapor pressures, obtained using a Knudsen cell technique, and near properties, obtained using a vacuum four-ball apparatus, were measured for a series of unformulated liquid lubricants. These include: two multiple alkylated cyclopentanes (MACs) (X-1000 and X-2000), two linear perfluoropolyalkylethers (PFPAEs) (Z-25 and 815Z), and four silahydrocarbons (a tri-, a tetra-, and two pentas). Vapor pressures were measured at three elevated temperatures (423, 448, and 498 K) and extrapolated to room temperature 298 K. The lowest 298 K vapor pressure of 5.7 x 10(exp -14) Pa, was obtained with the PFPAE fluid (815Z) and the highest value with the low molecular weight MAC (X-1000) at 3.6 x 10(exp -7) Pa. In addition, vacuum near rates were determined for some of the lubricants. The lowest wear rates (approximately 3 x 10(exp -11) cubic mm/mm) were observed for three of the silahydrocarbons while the highest wear rate (approximately 2 x 10(exp-9) cubic mm/mm) were observed with the two PFPAE fluids (Z-25 and 815Z). The MAC (X-2000) yielded a wear rate of about 10(exp -10) cubic mm/mm. The results indicated that the silahydrocarbon class of liquid lubricants offers the better potential for space applications.
Document ID
20020034132
Acquisition Source
Glenn Research Center
Document Type
Reprint (Version printed in journal)
Authors
Nguyen, Quynhgiao N.
(NASA Glenn Research Center Cleveland, OH United States)
Jones, William R., Jr.
(NASA Glenn Research Center Cleveland, OH United States)
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Publication Information
Publication: Tribology Transactions
Publisher: Society of Tribologists and Lubrication Engineers
Volume: 44
Issue: 4
Subject Category
Nonmetallic Materials
Meeting Information
Meeting: 55th Annual Meeting
Location: Nashville, TN
Country: United States
Start Date: May 7, 2000
End Date: May 11, 2000
Sponsors: Society of Tribologists and Lubrication Engineers
Distribution Limits
Public
Copyright
Other

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