Tribology Letters

, Volume 17, Issue 3, pp 367–376

Lubrication of Silicon Nitride and Silicon Carbide by Water: Running in, Wear and Operation of Sliding Bearings

  • Laurent Jordi
  • Christo Iliev
  • Traugott E. Fischer

DOI: 10.1023/B:TRIL.0000044485.77019.fb

Cite this article as:
Jordi, L., Iliev, C. & Fischer, T.E. Tribology Letters (2004) 17: 367. doi:10.1023/B:TRIL.0000044485.77019.fb


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.

water lubrication ceramics running in wear measurement tribochemistry 

Copyright information

© Springer Science+Business Media,Inc. 2004

Authors and Affiliations

  • Laurent Jordi
  • Christo Iliev
  • Traugott E. Fischer

There are no affiliations available

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