uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Carbon Release by Selective Alloying of Transition Metal Carbides
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. (oorgansik kemi)
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
Show others and affiliations
2011 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 23, no 35, 355401-+ p.Article in journal (Refereed) Published
Abstract [en]

We have performed first principles density functional theory calculations on TiC alloyed on the Ti sublattice with 3d transition metals ranging from Sc to Zn. The theory is accompanied by experimental investigations, both as regards materials synthesis as well as characterization. Our results show that by dissolving a metal with a weak ability to form carbides, the stability of the alloy is lowered and a driving force for the release of carbon from the carbide is created. During thin film growth of a metal carbide this effect will favour the formation of a nanocomposite with carbide grains in a carbon matrix. The choice of alloying element as well as its concentration will affect the relative amount of carbon in the carbide and in the carbon matrix. This can be used to design the structures of nanocomposites and their physical and chemical properties. One example of applications is as low-friction coatings. Of the materials studied, we suggest the late 3d transition metals as the most promising elements for this phenomenon, at least when alloying with TiC.

Place, publisher, year, edition, pages
2011. Vol. 23, no 35, 355401-+ p.
National Category
Inorganic Chemistry
Research subject
Inorganic Chemistry
URN: urn:nbn:se:uu:diva-123136DOI: 10.1088/0953-8984/23/35/355401OAI: oai:DiVA.org:uu-123136DiVA: diva2:312482
Available from: 2009-10-12 Created: 2009-10-12 Last updated: 2016-08-11Bibliographically approved
In thesis
1. Design of carbide-based nanocomposite coatings
Open this publication in new window or tab >>Design of carbide-based nanocomposite coatings
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In this thesis research on synthesis, microstructure and properties of carbide-based coatings is reported. These coatings are electrically conducting, and can be tailored for high hardness, low friction and wear, along with load-adaptive behaviour. Tailoring these properties is achieved by controlling the relative phase content of the material. Coatings have been synthesised by dc magnetron sputtering, and their structures have been characterised, mainly by X-ray photoelectron spectroscopy and X-ray diffraction.

It has been shown that nanocomposites comprising of a nanocrystalline transition metal carbide (nc-MeCx, Me = Ti, Nb or V) and an amorphous carbon (a-C) matrix can result in low contact resistance in electrical contacts. Such materials also exhibit low friction and high resistance to wear, making them especially suitable for application in sliding contacts. The lowest contact resistance is attained for small amounts of the amorphous carbon phase.

It has been shown that specific bonding structures are present in the interface between nc-TiCx and the a-C phases in the nanocomposite.  It was found in particular that Ti3d and C2p states are involved, and that considerable charge transfer occurs across the interface, thereby influencing the structure of the carbide.

Further design possibilities were demonstrated for TiCx-based nanocomposites by alloying them with weakly carbide-forming metals, i.e., Me = Ni, Cu or Pt.  Metastable supersaturated solid solution carbides, (T1-xMex)Cy, were identified to result from this alloying process. The destabilisation of the TiCx-phase leads to changes in the phase distribution in the deposited nanocomposites, thus providing further control over the amount of carbon phase formed. Additional design possibilities became available through the decomposition of the metastable (Ti1-xMex)Cy phase through an appropriate choice of annealing conditions, yielding either more carbon phase or a new metallic phase involving Me. This alloying concept was also studied theoretically for all 3d transition metals using DFT techniques.

It has also been demonstrated that Ar-ion etching (commonly used in the analysis of carbide based nanocomposites) can seriously influence the result of the analysis, especially for materials containing metastable phases. This implies that more sophisticated methods, or considerable care are needed in making these analyses, and that many of the earlier published results could well be in error.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2009. 83 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 682
chemistry, thin film, dc magnetron sputtering, carbide, nanocomposite, PVD, solid solution
National Category
Chemical Sciences Inorganic Chemistry
Research subject
Inorganic Chemistry
urn:nbn:se:uu:diva-109427 (URN)978-91-554-7636-6 (ISBN)
Public defence
2009-11-27, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Available from: 2009-11-06 Created: 2009-10-15 Last updated: 2014-01-21Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Råsander, MikaelLewin, ErikSanyal, BiplabKlintenberg, MattiasEriksson, OlleJansson, Ulf
By organisation
Inorganic ChemistryMaterials Theory
In the same journal
Journal of Physics: Condensed Matter
Inorganic Chemistry

Search outside of DiVA

GoogleGoogle Scholar
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

Altmetric score

Total: 495 hits
ReferencesLink to record
Permanent link

Direct link