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Parameters of lubricating films and rubbing surfaces in contacts operated in superlubricity regime
Poláček, Tomáš ; Hartl, Martin (referee) ; Šperka, Petr (advisor)
The work investigates the reduction of friction between non-conformal macro contacts with partial slip. The measurement of the coefficient of friction, with the magnitude of the superlubricity, is extended by the influence of relative slip, direct observation of the contact area and the measurement of the thickness of the lubricating film. It also includes a comparison of changes in topography by friction. The experiments were mainly performed on a ball-on-disk tribometer with measuring the film thickness by colorimetic interferometry. The surface roughness changes were investigated using an optical profilometer. The effect of mean velocity, slide-to-roll radio and topography were observed for selected combinations, one of which did not allow the measurement of film thickness and one did not achieve the expected reduction in friction. For the other combinations, it was possible to observe a reduction of the coefficient of friction to 0,003 or less. The influences affecting the friction between selected materials have been investigated considerably. Thus, a foundation is laid for the research of superlubricity between contacts with partial rolling. The thesis could contribute to the reduction of friction losses, earlier(quicker/faster?) and more common use of some lubricants and materials in mechanical engineering.
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Parameters of lubricating films and rubbing surfaces in contacts operated in superlubricity regime
Poláček, Tomáš ; Hartl, Martin (referee) ; Šperka, Petr (advisor)
The work investigates the reduction of friction between non-conformal macro contacts with partial slip. The measurement of the coefficient of friction, with the magnitude of the superlubricity, is extended by the influence of relative slip, direct observation of the contact area and the measurement of the thickness of the lubricating film. It also includes a comparison of changes in topography by friction. The experiments were mainly performed on a ball-on-disk tribometer with measuring the film thickness by colorimetic interferometry. The surface roughness changes were investigated using an optical profilometer. The effect of mean velocity, slide-to-roll radio and topography were observed for selected combinations, one of which did not allow the measurement of film thickness and one did not achieve the expected reduction in friction. For the other combinations, it was possible to observe a reduction of the coefficient of friction to 0,003 or less. The influences affecting the friction between selected materials have been investigated considerably. Thus, a foundation is laid for the research of superlubricity between contacts with partial rolling. The thesis could contribute to the reduction of friction losses, earlier(quicker/faster?) and more common use of some lubricants and materials in mechanical engineering.
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