On the phonon dissipation contribution to nanoscale friction by direct contact

S R Sales De Mello,C M Menezes,F Alvarez,M E H Maia Da Costa,C D Boeira,C A Figueroa,F L Freire Jr

doi:10.1038/s41598-017-03046-8

S R Sales De Mello, C M Menezes + Show 5 more

Open Access

https://doi.org/10.1038/s41598-017-03046-8

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Abstract

The friction phenomenon is a ubiquitous manifestation of nature. Models considering phononic, electronic, magnetic, and electrostatic interactions are invoked to explain the fundamental forces involved in the friction phenomenon. In order to establish the incidence of the phonon prompting at the nanoscale friction by direct contact, we study a diamond spherical dome sliding on carbon thin films containing different amount of deuterium and hydrogen. The friction coefficient decreases by substituting hydrogen by deuterium atoms. This result is consistent with an energy dissipation vibration local mechanism from a disordered distribution of bond terminators.

Highlights

The understanding of the physical causes and how controlling friction properties is a cutting edge challenge in order to save energy, diminishing wear, increasing the lifetime and sustainability of mechanical devices, and improving performance[1, 2]
An attempt to improve the understanding of the three-term kinetic friction model by using fundamental physical properties of the matter could help to unify several mechanisms prompting the friction at the nanoscale size that seem disconnected at the present
Several works have explored the physical nature of energy exchange, coupling interaction, and dissipation mechanisms affecting the phenomenological friction coefficient and shear stress between sliding surfaces[8]

Summary

Introduction

The understanding of the physical causes and how controlling friction properties is a cutting edge challenge in order to save energy, diminishing wear, increasing the lifetime and sustainability of mechanical devices, and improving performance[1, 2]. The non-conservative forces acting in the physical interaction between two surfaces in relative motion is not explained by a unique and fundamental physical mechanism This is in part due to the complexity of the dissipative forces involved in the phenomenon, strongly depending on the length scales of the sliding parts[5,6,7]. By the lack of better tools, molecular dynamics calculations are applied to inspect the macroscopic phenomenological three-term kinetic friction model (or part of it) to phenomena occurring at the nanoscale size[5, 6] This model assumes the combination of three effects, namely, the adhesion force in the presence of a lubricant at zero normal load (Derjaguin offset), the coefficient of friction (da Vinci-Amontons-Coulomb law) and the effective shear stress (Bowden-Tabor law)[6]. Spectra obtained from the a-C:D/H thin film deposited with 75% of CD4 in the gas mixture. (d) G-band position from Raman spectroscopy of the a-C:D/H thin films as a function of the deuterium content

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