Transfer Film Formation

On the Trail of Mysterious Third Bodies

In polymer-metal sliding contacts, transfer films significantly effect friction and wear. Despite intensive research, little is known about transfer film formation in non-standard climates. Therefore, a device for performing transfer film luminance analysis (TLA) in such climates was designed, fabricated and assembled. Preliminary experiments on tribologically modified polyamide sliding dry against 100Cr6 at 40°C indicate that transfer film formation is significantly enhanced by higher humidity. At the same time, however, the observed coefficient of friction also increases with humidity. This initially contradicts the usual explanation that more water is absorbed on the metal surface at higher humidity which should reduce the coefficient of friction. Only the realization that high humidity also favors transfer film formation provides an explanation for the observation made, since the increased adhesion between transfer film and polymeric test specimen compared to metal/plastic friction is a known effect of the formation of polymer-based transfer films.

Increased humidity favors the formation of polymerbased transfer films which in turn explains the observed  increase in the coefficient of friction with increasing humidity due to adhesion.

Field of competence

Project status

  • Current

Contacts

Dipl.-Chem.

Andreas Gebhard

Manager Tribology

Telephone: +49 631 2017 342

andreas.gebhard@ivw.uni-kl.de

Room: 58/433

Funding

The project “Impact of Transfer Film Formation Mechanisms on Friction and Wear of Polymeric Compounds“ was funded by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – 389811744.