The Quasi-Hydrodynamic Mechanism of Powder Lubrication: Part II: Lubricant Film Pressure Profile

Heshmat, H. “The Quasi-Hydrodynamic Mechanism of Powder Lubrication: Part II:  Lubricant Film Pressure Profile,” STLE Paper 91-TC-3D-3, STLE/ASME Tribology Conference, St. Louis, MO, October 14-16, 1991, (1992) Lubrication Engineering, Volume 48 (5), pp. 373-383.

The present work is the second in a series of three papers aimed at a systematic development of the concept of powder lubrication as a viable tribological process.  The quasi-hydrodynamic nature of powder lubrication is deduced from the observation that a number of basic features of powder flow in narrow interfaces exhibit the characteristic behavior of fluid film lubrication.  In addition to corroborating the basic mechanism of powder lubrication, the conceptual and experimental work performed here provides an evaluation of the parameters relevant to this particular tribological process.  the present part of the work presents experimental evidence of the formation of hydrodynamic pressure profiles in powder lubricants.  The tests were conducted for boundary, starvation, and flooded conditions of the lubricant film.  The added phenomenon in powder lubrication is the adherence of a thin powder layer to both surfaces, which contributes to the low-friction behavior of the tribological process.