Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Evaulation of liquid-exfoliatedgraphene as additive in Ag-basedsliding contacts
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
2018 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

This master thesis work is performed at ABB Corporate Research Center inVästerås. The aim of this study is to investigate Ag:graphene composites as slidingelectrical contacts, suitable for use in e.g. tap-changers. Three different graphenematerials, all produced by a low-cost exfoliation process, are evaluated in this study. The results are compred to an ongoing work on Ag:GO (graphene oxide) composites. This material has shown very good tribological properties, however it hasbeen difficult to handle during sintering processing. The goal of this study is to geteven better tribological, electrical and mechanical properties than Ag:GO, and also todevelop a new powder-metallurgical method to produce the Ag:graphene composites.The study also investigates the influence of graphene flake size and concentration aswell as microstructure of the Ag:graphene composites. This report focuses on aninvestigation of the graphene raw material quality from the suppliers, and friction,wear and resistance analysis of the composites. This is done by using Ramanspectroscopy, SEM with EDS, LOM, tribometer tests and resistivity analysis.

Raman and SEM analyses show that none of the supplied LEG materials are ofhigh-quality G (single or bilayer), but rather multi-layer graphene or even graphite.Small amounts of graphene added to Ag gave extremly low friction (μ<0.2 vs. pureAg μ~1.3, 5 N load and 5 cm/s speed). The composite manufacturing process hadcritical steps, which have to be optimized, to obtain low values of friction. Severedegassing of the composites was observed for some sampes, but the samples stillmaintained good friction values. SEM and EDS analyses of 2dfab’s wear track show abuild-up thin carbon-containing tribofilm on the Ag surface. Indicating that G ispresent, and works as a lubricant, creating good tribological properties. The resultsfrom this project may for sure be of importance for future ABB products in specificindustrial applications.

Place, publisher, year, edition, pages
2018. , p. 43
Series
UPTEC Q, ISSN 1401-5773 ; 18023
Keywords [en]
liquid-exfoliated graphene, liquid exfoliated graphene, graphene, sliding contacts, additive in Ag-based sliding contacts, Raman, SEM, EDS, tribometer, liquid exfoliation, liquid phase exfoliation
National Category
Metallurgy and Metallic Materials Other Materials Engineering
Identifiers
URN: urn:nbn:se:uu:diva-353942OAI: oai:DiVA.org:uu-353942DiVA, id: diva2:1219891
External cooperation
ABB Corporate Research Center Västerås
Subject / course
Material
Educational program
Master Programme in Materials Engineering
Supervisors
Examiners
Available from: 2018-06-21 Created: 2018-06-18 Last updated: 2018-06-21Bibliographically approved

Open Access in DiVA

fulltext(12187 kB)2 downloads
File information
File name FULLTEXT01.pdfFile size 12187 kBChecksum SHA-512
7b0a10d7e8fe041590389d2e1af396a55404d6f8f86951d7566672a28ce8bc7a958f910daeb84efd3cbe14c154c59f67672683dc7aee8b337e179fd5b3d8aeeb
Type fulltextMimetype application/pdf

By organisation
Applied Materials Sciences
Metallurgy and Metallic MaterialsOther Materials Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 2 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 9 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf