Abstract
The purpose of this work was to establish the conditions for the operation and break-in of water-lubricated ceramic bearings. The experiments consisted of sliding 1/4″ silicon nitride or—carbide balls against pre-polished disks of the same material in water until tribochemical wear generates smooth conformal surfaces that allow hydrodynamic lubrication (μ<0.002) by very thin water films. This “running in” was performed at various sliding speeds (0.01-4m/s) and loads (0.5-20N). The minimum sliding speed for low friction were 0.04m/s for silicon nitride and 0.5m/s for silicon carbide, much lower than for conventional bearings. The load carrying pressures were 60-80MPa, which is higher than the usually pressures of thrust bearings. The hydrodynamic fluid film thickness was estimated with a standard integration of Reynolds' equations modified for circular geometry, it was to be 5-15nm for silicon nitride, 25nm for silicon carbide. Operation over long distances (80km) allowed us to measure the wear rate during hydrodynamic lubrication; this was found to be <2×10−11mm3/nm, a rate acceptable for industrial application. A novel method completed during this work allows the determination of the wear rate during run-in. It varies with sliding velocity for silicon nitride, from 1 to 6×10−5mm3/nm; it is constant at 4×10−6mm3/nm for silicon carbide.
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References
H. Tomizawa and T.E. Fischer, ASLE Trans. 30 (1987) 41.
S.R. Hah and T.E. Fischer, J. Eletcrochem. Soc. 145 (1998) 1708-1714.
S.R. Hah and T.E. Fischer, J. Electrochem. Soc. 146 (1999) 1505-1509.
V. Muratov and T.E. Fischer, Annu. Rev. Mater. Sci. 30 (2000) 27-51.
J. Xu, K. Kato and T. Hirayama, Wear 205 (1997) 55-63.
H.-C. Wong, N. Umehara and K. Kato, Wear 218 (1998) 237-243.
J. Xu and K. Kato, Wear 245 (2000) 61-75.
M. Chen, K. Kato and K. Adachi, Wear 250 (2001) 246-255.
M. Chen, K. Kato and K. Adachi, Tribol. Int. 35 (2002) 129-135.
X. Wang, K. Kato, K. Adachi and K. Aizawa, Tribol. Int. 36 (2003)189-197.
S.M. Hsu, Presentation at DARPA Conference on Steam Engines, Los Angeles, November 20, 2002.
V.A. Muratov, T. Luangvaranunt and T.E. Fischer, Tribol. Int. 31 (1998) 601-611.
V.A. Muratov and T.E. Fischer, ''Tribochemical Reactions of Silicon Nitride in Aqueous solutions '', Finishing Adv. Ceram Glasses p. 245-257.
Z. Zhu, V. Muratov and T.E. Fischer, Wear Mat. Intl. Conf., Wear 225-229 (1999) 848-856.
A. Cameron, Basic Lubrication Theory (J. Wiley, New York, 1976).
X.-Z. Zhao, J.-J. Liu and T.E. Fischer, Wear (1997).
T.E. Fischer and H. Tomizawa, Wear 105 (1985) 29.
H. Tomizawa and T.E. Fischer, ASLE Trans. 29 (1986) 481.
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Jordi, L., Iliev, C. & Fischer, T.E. Lubrication of Silicon Nitride and Silicon Carbide by Water: Running in, Wear and Operation of Sliding Bearings. Tribology Letters 17, 367–376 (2004). https://doi.org/10.1023/B:TRIL.0000044485.77019.fb
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DOI: https://doi.org/10.1023/B:TRIL.0000044485.77019.fb