Study of the Influence of the Interactions between Wax Particles and Surfaces on the Properties of Thin Lubricating Films in a High-Pressure Contact

Abstract

Wax dispersions have been recently developed as lubricants because they combine good cooling and lubricating capabilities. To improve their effectiveness, the understanding of the lubrication mechanisms must be detailed. The rheological behavior of wax dispersions was studied and revealed the interactions between particles and their spatial organization within water. The effect of both the size and the concentration of particles was assessed. Moreover, the mechanisms of the thin-films formation in a brass contact have been investigated with an elastohydrodynamic tribometer. The simultaneous measurement of the friction coefficient and film thickness determines the growth kinetics of the boundary films and shows the role of the particles/surfaces interactions. Surface analyses were carried out to determine the nature of the interactions between the particles and the surfaces. The results indicate that particles with high affinity with metal surfaces form thin shear-resistant films.

KEY WORDS:

• Adverse Environments Tribology
• Boundary Lubrication
• Friction
• Lubricant Properties
• Lubricant Rheology
• Surface Films/Coatings
• Wear and Failure
• Metalworking Fluids

ACKNOWLEDGMENTS

The authors wish to thank Thierry Lemogne and Benoît Nauleau, Ecole Centrale de Lyon, for their cooperation in these investigations.

Presented at the STLE Annual Meeting in Calgary, Canada, May 7-11, 2006

Final manuscript approved April 30, 2007

Review led by Jerry Byers