The effect of prolonged exposure to 750{degree}C air on the tribological performance of PM212
- Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Mechanical and Aerospace Engineering
- National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
- Aerospace Design and Fabrication, Inc., Brook Park, OH (United States)
The effect of prolonged exposure to 750C air on tribological performance and dimensional stability of PM212, a high temperature, self-lubricating composite, is studied. PM212, contains 70% metal-bonded Cr{sub 3}C{sub 2}, 15% BaF{sub 2}/CaF{sub 2} eutectic and 15% silver. Rub blocks were fabricated from PM212 by cold isostatic pressing followed by sintering. Prior to tribo-testing, the rub blocks were exposed to 750C air from 100 to 1000 hours. Then, the rub blocks were slid against nickel-based superalloy disks in a double-rub-block tribometer in air under 66N load at temperatures from 25 to 750C with a sliding velocity of 0.36 m/s. Unexposed rub blocks were tested for baseline comparison. Friction coefficients ranged from 0.24 to 0.37 for unexposed rub blocks and from 0.32 to 0.56 for the exposed ones. Wear for both the composite blocks and superalloy disks was typically in the moderate to low range of 10{sup {minus}5} to 10{sup {minus}6} mm{sup 3} /N-m. Friction and wear data were similar for the rub blocks exposed for 100, 500, and 1000 hours. Prolonged exposure to 750C air increased friction and wear of the PM212 rub blocks at room temperature, but triboperformance remained unaffected at higher temperatures, probably due to formation of lubricous metal oxides. Dimensional stability of the composite was studied by exposing specimens of varying thicknesses for 500 hours in air at 750C. Block thicknesses were found to increase with increased exposure time until steady state was reached after 100 hours of exposure, probably due to oxidation.
- Research Organization:
- National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AI01-91CE50306
- OSTI ID:
- 10147856
- Report Number(s):
- DOE/NASA-50306-4; NASA-TM-106472; CONF-940503-1; ON: DE94011222; BR: EE0103000/EE5202000
- Resource Relation:
- Conference: Annual meeting of the Society of Tribologists and Lubrication Engineers,Pittsburgh, PA (United States),2-5 May 1994; Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
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