Wear

  1. Publication date: 15 December 2019

    Source: Wear, Volumes 440–441

    Author(s): Stanisław Kucharski, Grzegorz Starzyński

    Abstract

    Contact between a deformable, random rough surface and a rigid flat counterpart was investigated experimentally and theoretically. In the experimental setup, two modes of rough surface flattening were performed, namely normal compression and sliding (tangential load) in presence of normal compression. The load-approach relationship and friction coefficient were measured. After unloading the surface, the topography was measured using scanning profilometry. The deformation of roughness zone, i.e. evolution of the real contact area (RCA), and roughness parameters were analysed. A model based on statistical analysis and a finite element solution was applied to predict the load–approach relationship. The numerical and experimental results were compared. The effect of friction coefficient was discussed.

  2. Publication date: 15 December 2019

    Source: Wear, Volumes 440–441

    Author(s): M. Woydt

    Abstract

    Sub-stoichiometric oxides formed by tribo-oxidation were often analyzed in tribofilms, like γ-Ti3O5, Ti5O9 and Ti9O17 and Mo0,975Ti0,025O2 as well as double oxides, like β-NiMoO4 or NiTiO3. Thus, the contribution of sub-oxides with planar defects (TinO2n-1, Tin-2Cr2O2n-1) or as block-structures (Nb3n+1O8n-2) to the tribological profile of carbides by using monolithic oxides is of scientific interest and has model character.

    The tribological profiles of these model oxides under dry unidirectional sliding have shown, that sub-oxides have a contribution to the tribological behavior of carbides and cermets, when they are tribo-oxidatively formed, because their tribological profiles as monolithic materials are homologuous in part or totally, or compete with hardmetals or cermets, depending from the operating conditions regarded.