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European Synchrotron Radiation Facility Tests World's Hardest And Least Compressive Material

Date:
September 13, 2005
Source:
European Synchrotron Radiation Facility
Summary:
The tests at the European Synchrotron Radiation Facility have demonstrated the unique properties of a new material, the Aggregated Diamond Nanorods (ADNR). Synthesized recently by a team from the University of Bayreuth, this material has been identified as the hardest and least compressible material in the world. It could potentially replace diamonds in industry.
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Nanorods of many materials are proving very successful, and theirproperties often exceed that of nanotubes, making them excellentcandidates for industrial applications. Theoretical calculationspredicted that diamond nanorods too would have properties superior tothat of carbon nanotubes. But, so far, nobody had been able to actuallysynthesize diamond nanorods. This is no longer true. A team from theBayerisches Geoinstitut (Universität Bayreuth) has just reported thesynthesis of these aggregated diamond nanorods (ADNR) and theirremarkable properties, after having measured them at the European Synchrotron Radiation Facility.

The Bayreuth team tested the compressibility and density of thisnew material. Experiments conducted at the ESRF on the High-Pressurebeamline confirmed that the X-ray density of the ADNR material ishigher than that of diamond by 0.2 –0.4%; thus making it the densestform of carbon. Subsequent experiments, carried out by loading adiamond anvil cell with both single crystal diamond and ADNR material,in order to directly compare their behaviour under static load,identifies that ADNR is also 11% less compressible than diamond.

The combination of the hardness of the ADNR and its chemicalstability makes it a potentially excellent material for machiningferrous materials. "The fact that diamond nanorods are very dense andnon-compressible has not only strengthened theoretical predictions, butalso given a positive sign that they have very interesting uniqueproperties", explains Leonid Dubrovinsky, one of the authors of thepaper.

At the ESRF, researchers tested the "Vickers microhardness",using a diamond indenter. They showed directly that the probe tipfailed to make an indentation on the surface of the ADNR. Moreover ADNRcan scratch (111) faces of type-IIa natural diamonds, thus ADNR isharder than natural diamond and consequently more resistant againstabrasion. The random arrangement of the nanorods most probably givesrise to the increased hardness of ADNR and the reduction in C-C bondlength in outer layers of nanorods gives rise to the increased density.

Mechanical testing has also shown that under the sameconditions, due to the increased resistance against graphitisation,ADNR material is a much more effective grinding piece than synthetic ornatural diamond. This makes it a potentially valuable material inmachining ferrous metals and ceramics and, due to its nanocrystallinenature, for precision machining and polishing.

The invention of the team (Natalia Dubrovinskaia, LeonidDubrovinsky, and Falko Langenhorst) describing the method of synthesisof superhard, wear resistant, and thermally stable aggregated diamondnanorods and their applications has been patented.

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References:
(Ref.1) Natalia Dubrovinskaia, Leonid Dubrovinsky, Wilson Crichton, FalkoLangenhorst, Asta Richter. Aggregated diamond nanorods, the densest andleast compressible form of carbon. Applied Physics Letters, 22 August2005.
(Ref. 2) N.A. Dubrovinskaia, L.S. Dubrovinsky, F. Langenhorst.Verfahren zur Herstellung von nanokristallinem stäbchenförmigem Diamantund Anwendungen dafür. Deutsche Patentanmeldung: 10 2004 026 976.9, 2.Juni 2004.


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Cite This Page:

European Synchrotron Radiation Facility. "European Synchrotron Radiation Facility Tests World's Hardest And Least Compressive Material." ScienceDaily. ScienceDaily, 13 September 2005. <www.sciencedaily.com/releases/2005/09/050913125433.htm>.
European Synchrotron Radiation Facility. (2005, September 13). European Synchrotron Radiation Facility Tests World's Hardest And Least Compressive Material. ScienceDaily. Retrieved June 16, 2024 from www.sciencedaily.com/releases/2005/09/050913125433.htm
European Synchrotron Radiation Facility. "European Synchrotron Radiation Facility Tests World's Hardest And Least Compressive Material." ScienceDaily. www.sciencedaily.com/releases/2005/09/050913125433.htm (accessed June 16, 2024).

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