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Analysis of Short and Long Range Atomic Order in Nanocrystalline Diamonds with Application of Powder DiffractometryFundamental limitations, with respect to nanocrystalline materials, of the traditional elaboration of powder diffraction data like the Rietveld method are discussed. A tentative method of the analysis of powder diffraction patterns of nanocrystals is introduced which is based on the examination of the variation of lattice parameters calculated from individual Bragg lines (named the "apparent lattice parameter", alp). We examine the application of our methodology using theoretical diffraction patterns computed for models of nanocrystals with a perfect crystal lattice and for grains with a two-phase, core-shell structure. We use the method for the analysis of X-ray and neutron experimental diffraction data of nanocrystalline diamond powders of 4, 6 and 12 nm in diameter. The effects of an internal pressure and strain at the grain surface is discussed. This is based on the dependence of the alp values oil the diffraction vector Q and on the PDF analysis. It is shown, that the experimental results support well the concept of the two-phase structure of nanocrystalline diamond.
Document ID
20020066656
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Palosz, B.
(Polish Academy of Sciences Warsaw, Poland)
Grzanka, E.
(Polish Academy of Sciences Warsaw, Poland)
Stelmakh, S.
(Polish Academy of Sciences Warsaw, Poland)
Pielaszek, R.
(Polish Academy of Sciences Warsaw, Poland)
Bismayer, U.
(Hamburg Univ. Germany)
Neuefiend, J.
(Deutsches Elektronen-Synchrotron Hamburg, Germany)
Weber, H.-P.
(European Synchrotron Radiation Facility Grenoble, France)
Proffen, T.
(Los Alamos National Lab. NM United States)
VonDreele, R.
(Los Alamos National Lab. NM United States)
Palosz, W.
(Universities Space Research Association Huntsville, AL United States)
Curreri, Peter A.
Date Acquired
August 20, 2013
Publication Date
January 1, 2002
Subject Category
Solid-State Physics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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