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Chemical modification in wear tracks of chemical vapor deposited diamond surfaces studied with X-ray absorption spectroscopy
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Soft X-Ray Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
2008 (English)In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 32, no 1, 31-34 p.Article in journal (Refereed) Published
Abstract [en]

We present high-quality X-ray absorption near edge structure spectra of chemical vapor-deposited diamond at the C K-edge recorded with high spatial resolution. We compare unworn surfaces with surfaces worn in Ar-atmosphere, in air, and in water, respectively. Strikingly, the degree of chemical modification in the wear tracks is strongest for wear in an inert Ar-atmosphere which we attribute to the massive creation of unsaturated bonds in the surface vicinity due to high friction forces. We discuss the nature of chemical modification, in particular, whether and to what degree graphitization, amorphization, and ex situ reactions take place.

Place, publisher, year, edition, pages
2008. Vol. 32, no 1, 31-34 p.
Keyword [en]
diamond, carbon, graphite, unlubricated friction, NEXAFS, abrasive wear
National Category
Engineering and Technology
URN: urn:nbn:se:uu:diva-91767DOI: 10.1007/s11249-008-9357-7ISI: 000259699300004OAI: oai:DiVA.org:uu-91767DiVA: diva2:164603
Available from: 2004-04-28 Created: 2004-04-28 Last updated: 2016-04-12Bibliographically approved
In thesis
1. Microengineered CVD Diamond Surfaces: Tribology and Applications
Open this publication in new window or tab >>Microengineered CVD Diamond Surfaces: Tribology and Applications
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Recent developments in thin film synthesis of diamond have facilitated a host of new technical applications. These are motivated by the many attractive properties of diamond, for example high hardness, chemical inertness, transparency and heat conductivity. Unfortunately, these properties also make it difficult to fashion complex geometries. Other problems are the severely limited choice of suitable substrate materials and large surface roughness. To reduce these complications, a technology denoted replication and bodybuilding has been developed. The basic principle is to grow the diamond film onto a mold and then build a mechanical support on top of the diamond film. Then the mold is removed. Thereby, a diamond surface with the desired 3D geometry and the same surface roughness as the mold is created.

Three potential applications for devices built using the replication and bodybuilding concept have been explored. Grinding tools for hard materials have proved superior to conventional technology in rate of removal as well as in resulting surface finish. Diamond surfaces have also been crafted into ultra-durable dies for injection molding of hard particle reinforced polymers. Initial testing of an abrasive diamond device, intended to make CMP processes more economical and easier to control has successfully been carried out.

Diamond and diamond-like carbon is well-known for being “low-friction materials”, but are here demonstrated to actually be “high-friction materials” with the ability to disguise themselves in certain environments, most notably with the aid of water molecules. The mechanisms involved in these variations have been investigated. Using NEXAFS it is shown that high friction sliding is accompanied by changes in the material structure. These changes are induced by surface roughness as well as by strong adhesive forces.

Highly hydrogenated carbon coatings, on the other hand, affording super-low friction coefficients (<0.01) under certain circumstances, will suffer an increase in friction in the presence of water.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2004. 51 p.
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-232X ; 977
Materials science, Diamond, DLC, Tribology, Friction, Environment, Microengineering, Materialvetenskap
National Category
Materials Engineering
urn:nbn:se:uu:diva-4261 (URN)91-554-5967-6 (ISBN)
Public defence
2004-05-19, Siegbahnsalen, Ångströmlaboratoriet, Regementsvägen 1, Uppsala, 10:00
Available from: 2004-04-28 Created: 2004-04-28Bibliographically approved

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