Si-DLC coatings optimized for low wear and low friction applications.
type: CreativeWork
description: Diamond-like carbon (DLC) has excellent properties for the use as tribological coating such as high hardness, high wear resistance and a low friction coefficient. Nanolayer systems of hydrogenated diamond-like carbon (a-C:H) and silicon doped hydrogenated diamond-like carbon (Si-DLC or a-C:H:Si) have been studied. The objectives of this work are to develop layer combinations which allow combining low abrasive wear, low friction properties, and improved temperature stability for the coatings.A literature survey on sputtering, plasma enhanced chemical vapor deposition (PECVD) and carbon based materials with a focus on a-C:H and Si-DLC coatings is given. This survey includes a brief overview of the 60 years history of DLC coating.In the second part of the thesis, the experimental set up for the layer preparation by a magnetron based deposition method and a basic description of the process are presented. Using sputtering from a solid SiC target as a source of the Si for the Si-DLC instead of the commonly used PECVD process with Si-containing precursors Si-DLC/a-C:H nanolayers were deposited at high deposition rates.For the coatings, the influence of the acetylene gas flow, the bias voltage, and the hydrogen and silicon concentration are discussed. Undoped a-C:H coatings with high indentation hardness above 40 GPa and very low abrasive wear rates of 0.6 x 10[-15] m[3]/(Nm) and low hydrogen content of about 11 at.% were deposited. Si-DLC/a-C:H nanolayer coatings with high hardness of 20 to 30 GPa and a high temperature stability up to 500 °C were prepared. For these nanolayer films low friction coefficients of 0.06 to 0.11 and high abrasive wear rates of >2.5 x 10[-15] m3/(Nm) were achieved at high silicon contents above 15 at.%. On the other hand nanolayer coatings with low silicon contents of less than 10 at.% showed low wear rates below 1.7 x 10[-15] m3/(Nm) combined with higher friction coefficients of 0.12 to 0.15. In order to combine the low abrasive wear rate and t…
abstract: Diamond-like carbon (DLC) has excellent properties for the use as tribological coating such as high hardness, high wear resistance and a low friction coefficient. Nanolayer systems of hydrogenated diamond-like carbon (a-C:H) and silicon doped hydrogenated diamond-like carbon (Si-DLC or a-C:H:Si) have been studied. The objectives of this work are to develop layer combinations which allow combining low abrasive wear, low friction properties, and improved temperature stability for the coatings.A literature survey on sputtering, plasma enhanced chemical vapor deposition (PECVD) and carbon based materials with a focus on a-C:H and Si-DLC coatings is given. This survey includes a brief overview of the 60 years history of DLC coating.In the second part of the thesis, the experimental set up for the layer preparation by a magnetron based deposition method and a basic description of the process are presented. Using sputtering from a solid SiC target as a source of the Si for the Si-DLC instead of the commonly used PECVD process with Si-containing precursors Si-DLC/a-C:H nanolayers were deposited at high deposition rates.For the coatings, the influence of the acetylene gas flow, the bias voltage, and the hydrogen and silicon concentration are discussed. Undoped a-C:H coatings with high indentation hardness above 40 GPa and very low abrasive wear rates of 0.6 x 10[-15] m[3]/(Nm) and low hydrogen content of about 11 at.% were deposited. Si-DLC/a-C:H nanolayer coatings with high hardness of 20 to 30 GPa and a high temperature stability up to 500 °C were prepared. For these nanolayer films low friction coefficients of 0.06 to 0.11 and high abrasive wear rates of >2.5 x 10[-15] m3/(Nm) were achieved at high silicon contents above 15 at.%. On the other hand nanolayer coatings with low silicon contents of less than 10 at.% showed low wear rates below 1.7 x 10[-15] m3/(Nm) combined with higher friction coefficients of 0.12 to 0.15. In order to combine the low abrasive wear rate and t…
author: Hofmann, Dieter.
language: en
date published: 2014
date modified: 2026-07-24T06:31:27Z
provider: Sheffield Hallam University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Sheffield Hallam University (United Kingdom).