Ex-oxalate magnesium oxide, a strain-free nanopowder studied with diffraction line profile analysis

An analysis of the microstructure of nanocrystalline magnesium oxide produced by thermal decomposition of magnesium oxalate, in the temperature range 500 °C–1200 °C, is described. The study is based on diffraction line broadening analysis carried out with the integral breadth (Langford) and Fourier methods, combined with the pattern decomposition technique. Additionally, the whole pattern matching method is also applied. No marked line broadening anisotropy is observed in the patterns. It is shown that the nanopowders are characterized by minimal strain and that crystallites have an average spherical shape. Volume-weighted and area-weighted apparent sizes are in the ranges 98–480 Å and 72–282 Å, respectively, within the temperature range considered. The results obtained from line broadening analysis are compared to those observed with scanning electron microscopy and surface area measurements. A satisfactory agreement is found between sizes derived from the different techniques.

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X-ray diffraction line broadening due to dislocations in non-cubic crystalline materials. III. Experimental results for plastically deformed zirconium

Journal of Applied Crystallography ◽

10.1107/s0021889889001585 ◽

1989 ◽

Vol 22 (4) ◽

pp. 299-307 ◽

Cited By ~ 63

Author(s):

R. Kužel ◽

P. Klimanek

Keyword(s):

Profile Analysis ◽

Theoretical Calculations ◽

Diffraction Line ◽

Line Profile Analysis ◽

Line Broadening ◽

X Ray Diffraction ◽

X Ray ◽

Diffraction Line Profile ◽

Analytical Functions ◽

Profile Fitting

Procedures of X-ray diffraction line profile analysis for the evaluation of the dislocation content in plastically deformed hexagonal materials were tested by means of conventional powder diffractometry on polycrystalline zirconium deformed under tension at 77 K. In order to obtain a representative picture of the dislocation-induced X-ray line broadening a series of reflections was measured. The integral breadths and the Fourier coefficients were evaluated by both direct profile-shape analysis and profile fitting with analytical functions. The results show a significant anisotropy of the line broadening. The 0001 reflections are clearly less broadened than most of the others. According to the theoretical calculations presented previously such a phenomenon can be expected if the plastic deformation favours generation of dislocations with Burgers vectors a/3 〈2{\bar 1} {\bar 1}0〉.

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A study of nanocrystalline yttrium oxide from diffraction-line-profile analysis: comparison of methods and crystallite growth

Powder Diffraction ◽

10.1154/1.1523077 ◽

2002 ◽

Vol 17 (4) ◽

pp. 262-269 ◽

Cited By ~ 13

Author(s):

D. Louër ◽

T. Bataille ◽

T. Roisnel ◽

J. Rodriguez-Carvajal

Keyword(s):

Yttrium Oxide ◽

Profile Analysis ◽

Line Profile Analysis ◽

Crystallite Growth ◽

Line Broadening ◽

Diffraction Line Profile ◽

Pattern Decomposition ◽

Refinement Method ◽

Two Samples ◽

On Line

An analysis of the microstructure of nanocrystalline yttrium oxide produced by thermal decomposition of a double oxalate yttrium and ammonium, at temperatures in the range 600 °C to 900 °C, is described. The study is based on line broadening analysis carried out with the (Voigt/Langford) integral breadth and Fourier methods combined with the pattern decomposition technique. Due to the line overlap arising from the density of diffraction lines, the whole pattern refinement method (pattern matching and Rietveld approaches) is also applied. No marked line broadening anisotropy is observed in the patterns. It is shown that for the two samples prepared at the highest temperatures the results are similar whatever the method used and the material can be considered as strain free. For the two lowest temperatures only the whole pattern refinement method is applied. The results suggest that a small amount of lattice microdistortion is present in these two last samples. It is shown that the crystallite growth varies exponentially with temperature. The results obtained from line broadening analysis are compared to those observed with scanning electron microscopy, from which a good accordance is noted between the two techniques.

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