Annonce de séminaire - École Centrale de Lyon

Annonce de séminaire
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UMR 5513
et la Fédération de Recherche “Matériaux“ - FR 2145
Friction and wear of fullerene-like
WS2 nanoparticles
Prof. Lev RAPOPORT
Holon Institute of Technology – Israel
Tribology Laboratory
[email protected]
www.hait.ac.il/labs/tribology/
Abstract
In the past few years, WS2 and MoS2 nanoparticles (IF) have been synthesized in the
Weizmann Institute. It has been established that IF-WS2 nanoparticles mixed in oil appear to enhance
the tribological properties in definite loading range in comparison to typical metal dichalcogenides. The
slippery nature of IF nanoparticles leads to their fast displacement from the contact area, and
consequently the efficacy of their lubrication is maintained so long as they can be replenished to the
contact area. By confining the IF nanoparticles inside a porous and densified solid matrix, slow
release of the nanoparticles onto the metal surface alleviates both friction losses and wear, while
assuring the mechanical integrity of the composite.
The main goal of this work was to analyze the effects of IF solid lubricant in oil, grease and
their impregnation with oil into the porous matrixes on friction and wear of different contact pairs. It
was found that impregnation of IF nanoparticles provides the regime of quasi-hydrodynamic
lubrication over the widest range of loads in comparison to commercially available solid lubricant. The
effect of load and sliding velocity on a stability of the IF nanoparticles is discussed. The results of
friction and wear experiments with powdered bronze, iron and iron-nickel parts impregnated with
commercially available layered 2H-WS2 particles and IF-WS2 (fullerene-like) nanoparticles are
presented. The main advantages of the impregnated IF nanoparticles appeared to be their long-term
storage in the porous media, and their subsequent gradual furnishing to the contact surface. The
effect of IF on the lubrication regime is explained on the basis of a third-body model. In order to
explain the damage of IF nanoparticles, solid lubricant nanopowder was compressed and analyzed by
different methods. TEM, SEM, XPS, Raman and AFM techniques are used in order to evaluate the
effect of IF on friction and wear of contact pairs.
date
lieu
vendredi
18 avril 2003
36, rue Guy de Collongue, ÉCULLY
10h30 – 11h30
salle B11
bâtiment H10, rdc
Contact :
Jean-Michel MARTIN
École Centrale de Lyon
[email protected] tél. 04 72 18 62 83