Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 59: Poster Session III (Nanotribology; Polymeric biomolecular films; Organic electronics and photovoltaics, Covalent networks on surfaces; Phase transitions; Particles and clusters; Transparent conductive oxides)
O 59.4: Poster
Mittwoch, 16. März 2011, 17:30–21:00, P3
Wear experiments on the nanoscale — •Johannes Sondhauß1,2 and André Schirmeisen1,2 — 1Institute of Physics, University of Münster, Münster, Germany — 2Center for Nanotechnology (CeNTech), University of Münster, Münster, Germany
The basic mechanisms of wear at the nanoscale are of large interest, e.g., for the lifetime limitations of moving mechanical components in MEMS. So far it was not possible to derive macroscopic wear behavior from fundamental processes on small scales. The atomic force microscope (AFM) has been recently proved useful to model a single sliding asperity in order to study wear processes on the atomic scale [1]. It was found that nanoscale wear is dominated by an atom-by-atom loss process which can be modeled by a thermally activated bond breaking process. In this work we performed several wear experiments using different Si-tips sliding for distances from a few hundreds of µm to about 2m on a silicon oxide surface. We varied the applied normal load and performed measurements under ambient conditions and in UHV. The change of the tip radius due to wear was determined from the adhesion force at different sliding distances. As a further channel we simultaneously measured the friction force acting between tip and sample. Our results seem to agree with the model, that frictional stresses lower the barrier for breaking an atomic bond and thus are jointly responsible for the observed characteristic wear rates at the nanoscale.
[1] Gotsmann and Lantz, Phys. Rev. Lett. 101, 125501 (2008)