Deterministic Friction Model of a Rough Surface Sliding Against a Flat Layered Surface

Abstract

In this paper, a layered surface is modeled like a solid that has effective mechanical properties (E eff (x), m eff (x) and H eff (x)) as a function of indentation depth (x) and the rough surface is modeled as a population of spherically shaped asperities with different radii and heights (not necessarily Gaussian distributed). The contact behavior and the resistant to motion experienced by each asperity is analyzed locally and summarized as the total friction force based on the adhesion and ploughing mechanisms. The present model extends the capability of Halling's model to predict friction of layered surfaces. With this model, one is able to predict the friction of soft layer on a hard substrate and hard layer on a soft substrate in contact with a rough counter surface.

Low Friction in CuO‐Doped Yttria‐Stabilized Tetragonal Zirconia Ceramics: A Complementary Macro‐ and Nanotribology Study

“…Commercially available 10‐mm‐diameter α‐Al 2 O 3 balls (GIMEX Technische Keramiek BV, Geldermalsen, the Netherlands) with a grain size of 0.1–0.3 μm, and 10‐mm‐diameter Si 3 N 4 balls (HPSN, GIMEX Technische Keramiek BV) were used as the counter surface. The data agreed to within the experimental error with previously reported data acquired on multiple specimens prepared using the same protocols 22–27 …”

“…This observation may indicate that during sliding an interfacial layer with low shear strength is generated and that the AFM measurements were performed on this layer. While these results do not provide a complete explanation for the process of layer formation, they represent the first report of bridged nano‐ and macrotribological analysis of a compositionally heterogeneous low‐friction, low‐wear ceramic material, and confirm some of the key assumptions for the model by Pasaribu and Schipper 24,25 …”

“…The first situation (i) is predicted by the model for layer thickness above 1 μm 25 . The second case (ii) was observed experimentally for the macroscopic coefficient of friction for sliding distances above 1000 m. Because the roughness of track for 300 and 450 m sliding distances (tracks E and F) was practically the same, we can exclude (ii) as a reason for the increase in with respect to .…”

“…The study reported below was focused on the quantitative characterization of the macro‐ and nanotribological behavior of the soft layer formed in the wear tracks between an α‐Al 2 O 3 ball and CuO‐doped 3Y‐TZP 22,26 . The narrowing of the gap of experimental length and time scales will allow a direct comparison of the data obtained in pin‐on‐disk and AFM tribology measurements and thereby help to unravel new insight required to confirm and improve recently developed models for solid lubrication under dry sliding conditions 25,34 …”

“…To explain these results, Pasaribu and Schipper 25 proposed a friction model for layered systems based on a deterministic contact model. In this model, the rough surface is represented by a distribution of spherically shaped asperities with different radii and heights (Scheme 1).…”