| AVS 63rd International Symposium & Exhibition | |
| Tribology Focus Topic | Wednesday Sessions |
| Session TR+AS+NS+SS-WeA |
| Session: | Nanoscale Wear: Applications to Nanometrology and Manufacturing |
| Presenter: | Dirk Dietzel, Institute of Applied Physics, Justus-Liebig-University Giessen, Germany |
| Authors: | M. Feldmann, Institute of Applied Physics, Justus-Liebig-University Giessen, Germany D. Dietzel, Institute of Applied Physics, Justus-Liebig-University Giessen, Germany A. Schirmeisen, Institute of Applied Physics, Justus-Liebig-University Giessen, Germany |
| Correspondent: | Click to Email |
On the macroscale, the distinct difference between static and sliding friction can well be explained by the phenomenon of contact ageing, which is typically related to an increase of contact area with time within a multi asperity interface model. On the nanoscale, however, the role of contact ageing is less clear, especially when considering nanoscale asperities of constant size.
Recently, the role of contact ageing for nanoscale friction dynamics was analyzed for antimony nanoparticles sliding on HOPG. The antimony nanoparticles have been prepared by thermal evaporation on HOPG and comprise an ideal model system with atomically flat interfaces of constant size where friction can be described by the concept of structural superlubricity [1]. Friction of the particles was assessed by nanomanipulation techniques and it was found, that sliding friction can be described as a complex process of thermally activated contact ageing and bond breaking [2]. Further measurements have now revealed, that the particle movement follows an irregular stick slip pattern, where the slip events can be considered as recurring contact renewal, while the stick times can be interpreted as the age of the contact. By correlating the stick times with the lateral force values measured for contact breaking, we found that our system can well be described by logarithmic ageing [3], as it might be expected by assuming atom by atom relaxation processes at the interface.
To check whether ageing during sliding motion is fundamentally different from ageing under stationary conditions, we have performed additional “slide hold slide” measurements [4] and found that in both cases ageing can be described by exactly the same logarithmic function. This indicates, that the strength of the contact is determined by the ageing time but independent of the kinetic conditions. This means that static and sliding friction can be described by a universal ageing law where the age of the contact is the crucial parameter.
[1] D. Dietzel, M. Feldmann, H. Fuchs, U.D. Schwarz, A. Schirmeisen, Phys. Rev. Lett. 111, 235502 (2013)
[2] M. Feldmann, D. Dietzel, H. Fuchs, A. Schirmeisen, Phys. Rev. Lett. 112, 155503 (2014)
[3] M. Feldmann, D. Dietzel, A. Tekiel, J. Topple, P. Gruetter, A. Schirmeisen, Phys. Rev. Lett. 117, 025502 (2016)
[4] Q. Li, T.E. Tullis, D. Goldsby, R. W. Carpick, Nature 480, 233-236 (2011)