scholarly journals Nanocrystalline materials studied by powder diffraction line profile analysis

2007 ◽  
Vol 222 (3-4) ◽  
Author(s):  
Tamas Ungár ◽  
Jeno Gubicza
Keyword(s):  
Electron Microscopy ◽  
Powder Diffraction ◽  
Nanocrystalline Materials ◽  
Profile Analysis ◽  
Line Profile Analysis ◽  
Ray Method ◽  
Crystalline Materials ◽  
X Ray ◽  
Diffraction Line Profile ◽  
The One

X-ray powder diffraction is a powerful tool for characterising the microstructure of crystalline materials in terms of size and strain. It is widely applied for nanocrystalline materials, especially since other methods, in particular electron microscopy is, on the one hand tedious and time consuming, on the other hand, due to the often metastable states of nanomaterials it might change their microstructures. It is attempted to overview the applications of microstruture characterization by powder diffraction on nanocrystalline metals, alloys, ceramics and carbon base materials. Whenever opportunity is given, the data provided by the X-ray method are compared and discussed together with results of electron microscopy. Since the topic is vast we do not try to cover the entire field.

Anisotropic microstrain broadening in cementite, Fe3C, caused by thermal microstress: comparison between prediction and results from diffraction-line profile analysis

2012 ◽  
Vol 45 (5) ◽  
pp. 944-949 ◽  
Author(s):  
A. Leineweber
Keyword(s):  
Powder Diffraction ◽  
Elastic Anisotropy ◽  
Profile Analysis ◽  
Thermal Shrinkage ◽  
Line Profile Analysis ◽  
Powder Diffraction Data ◽  
Preparation Temperature ◽  
X Ray ◽  
Diffraction Line Profile ◽  
Ambient Analysis

X-ray powder diffraction data of an Fe3C powder consisting of polycrystalline particles shows pronouncedly anisotropic microstrain broadening of the Bragg reflections. The extent and anisotropy of the broadening can quantitatively be attributed to thermal microstresses induced by anisotropic thermal shrinkage from the preparation temperature of 873 K to the ambient analysis temperature, in conjunction with the elastic anisotropy of Fe3C.

Laboratory X-ray powder diffraction: a comparison of different geometries with special attention to the usage of the CuKα doublet

1999 ◽  
Vol 32 (4) ◽  
pp. 799-807 ◽  
Author(s):  
Martin Oetzel ◽  
Gernot Heger
Keyword(s):  
Powder Diffraction ◽  
Profile Analysis ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Strong Dependence ◽  
Line Profile Analysis ◽  
X Ray ◽  
Diffraction Angle ◽  
Maximum Parameters ◽  
The Right

In a laboratory X-ray powder diffraction study, the evaluation of the patterns of three Bragg–Brentano powder diffractometers with different monochromator geometries has been undertaken. For the measurements on each diffractometer, the standard reference material SRM 640 (silicon) and the corundum samples SRM 674a and SRM 1976 have been used. In each case, the peak profiles were fitted with a split Pearson VII function and the FWHM (full width at half-maximum) parameters and exponentmwere determined for the left (lower 2θ) and the right (higher 2θ) sides of the Bragg peaks. It was found that there is a strong dependence of both the FWHM and the exponentmon the diffraction angle for the two configurations that included monochromators, whereas nearly constant values ofmwere found for the geometrically simplest diffractometer working without a monochromator. Finally, the two components of the CuKα doublet show systematically different peak profiles. There is a clear difference not only concerning the FWHM, which becomes more obvious at higher 2θ values, but also in the course ofmwith respect to the diffraction angle for the left and the right tails of the powder reflections. This is the main reason for the difficulties inKα2stripping and also in single-line-profile analysis when using theKα doublet. Therefore, it is not surprising that this phenomenon, which can be explained by Heisenberg's uncertainty principle, does affect the reliability (represented by standardRvalues) of structure refinement by the Rietveld method.

Distributions of Domain Size, Lattice Distortion and Dislocation Density in Tubes of Zr-Based Alloys Studied by a Method Combining X-Ray Line Profile Analysis with Texture Measurements

2004 ◽  
Vol 443-444 ◽  
pp. 255-258 ◽  
Author(s):  
Yuriy Perlovich ◽  
Margarita Isaenkova
Keyword(s):  
Dislocation Density ◽  
Lattice Distortion ◽  
Profile Analysis ◽  
Domain Size ◽  
Line Profile Analysis ◽  
Ray Method ◽  
Texture Measurement ◽  
X Ray ◽  
Pole Figures ◽  
Line Analysis

The distributions of substructure parameters for tubes of Zr-based alloys were constructed by use of the X-ray method of Generalized Pole Figures, combining X-ray line analysis and texture measurement. Obtained distributions cover α-Zr crystallites of all orientations and give the fullest description of substructure features of the studied tubes. The interconnection of different substructure parameters are analyzed.

Defect Structures in Neutron Irradiated 6H-SiC Studied by X-Ray Diffraction Line Profile Analysis

2000 ◽  
Vol 640 ◽  
Author(s):  
C. Seitz ◽  
A. Magerl ◽  
R. Hock ◽  
H. Heissenstein ◽  
R. Helbig
Keyword(s):  
Line Profile ◽  
Correlation Length ◽  
Defect Structure ◽  
Profile Analysis ◽  
Line Profile Analysis ◽  
Defect Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Temperatures ◽  
Diffraction Line Profile

ABSTRACTWe have investigated by x-ray diffraction defect structures in 6H-SiC after neutron irradiation with different fluences and followed by different annealing procedures. An interpretation along a model of Klimanek [1, 4–6] shows, that higher fluences lead to a stronger than linear reduction of the correlation length, whereas higher annealing temperatures correlate with a better recovery of the correlation length. In addition defects of 1st kind created by irradiation are reduced by annealing. We find that annealing changes the character of the defects and it accentuates a defect structure already present in the original samples.

X-Ray Diffraction Study of Shock-Modified Tetragonal Phases of SnO2 and MnO2

1992 ◽  
Vol 36 ◽  
pp. 595-601
Author(s):  
P. Newcomer ◽  
B. Morosin ◽  
R. A. Graham
Keyword(s):  
Shock Loading ◽  
Crystal Size ◽  
Lattice Strain ◽  
Profile Analysis ◽  
Line Profile Analysis ◽  
X Ray Diffraction ◽  
Pressure Shock ◽  
X Ray ◽  
Diffraction Line Profile ◽  
Coherent Crystal

AbstractX-ray diffraction line-profile analysis on tetragonal forms of SnO2 (cassiterite), MnO2 (pyrolusite), and previously studied TiO2 (rutile), which were subjected to high pressure shock loading, show that residual lattice strain and coherent “crystal” size are a function of shock parameters. An interesting observation on a sample of MnO2 concerns the recovery of cubic Mn2O3 (bixbyite) in the material subjected to 22 GPa, indicating a shock-induced chemical synthesis.

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