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Jorn Larsen-Basse

National Science Foundation

The Integrated Tribological Surface – Cross-Disciplinary Research Challenges

The great tribologist David Tabor stated that “God created materials, the Devil made their surfaces”. This somewhat dim view of the difficulties in understanding the functions and properties of the tribological surface is not far from the truth – for lack of proper knowledge the surface remains the least “designed” or “engineered” part of any tribological system. This may be about to change, however, as discussed here from a very personal point of view.

Recent work has demonstrated that by specifically engineering the surface topography, friction reductions of 10-30% may be possible, particularly in boundary lubricated contacts. These include piston rings, gears, and many other very commonly used systems which consume a large part of the energy used in mass applications such as transportation. Therefore, the potential energy savings on a world-wide basis may be enormous. The current challenge is to understand the mechanisms behind this newly-discovered effect so that surface topography can be optimized. Following that, the integrated design and engineering of the surface as a system becomes the next challenge. This will have to include contributions from many different disciplines, from design and mechanics of controllable molecules, molecular films and molecular islands, to fluid behavior in confined nano- and micro-scale channels, microstructure-molecule interactions, coatings, surface modification, sensing and smart surface materials, and others. Integrated experimental and modeling efforts will be necessary. While the challenges are great the potential intellectual and societal rewards are greater.