Marcus Björling at a Wedeven associates machine ball on disc tribotester that measures the friction between a ball and a disc. The machine can examine various types of oils, coatings and materials in different operating conditions.

LTU's tribology research in Nature

Published: 17 January 2014

In the latest issue of Nature, perhaps the world's most prestigious scientific journal, an article from Luleå University of Technology is presented under "Research Highlights". It is tribology researcher Marcus Björling with colleagues who discovered a new friction-reducing effect of surface coatings.

– It's really great to be recognized in Nature, and something that gives huge PR for both our research at Machine Elements and for LTU at large. We almost got a full publication, but unfortunately we had already revealed a bit too much in a previous article in another journal. The first article we wrote about this received the Best Paper Award from the tribology organization STLE, says Marcus Björling.

A ball and a disc coated with DLC.
A ball and a disc coated with DLC.

The attention in Nature is proof that Marcus Björling and his colleagues is on something big. The research focus on a coating consisting of an extremely thin diamond-like carbon (DLC) which lowers friction in elasto hydrodynamically lubricated contacts. Previously, this friction reduction was explained by a theory that the lubricant was sliding against the coated surfaces including lower wetting than steel. The new and additional theory presented in this article show that the coating, which is thermally insulating, produces higher temperatures in the oil film between the contact surfaces, which reduces friction without compromising the protective oil film. The discovery provides the ability to construct new types of coatings with greater friction reducing properties which probably can be done cheaper than today's coatings.

– This is something completely new and everyone in the tribology society are not yet confident in our theory. In the article that was mentioned in Nature, we show evidence through simulations that our theory is correct, and we will continue to do research on this, says Marcus Björling.

The article is a collaboration between LTU researchers Marcus Björling, Roland Larsson and Pär Marklund, and the prominent tribology researchers Wassim Habchi (Lebanon) and Scott Bair (USA).