scholarly journals Texture Analysis of Quartzite by Whole Pattern Deconvolution

1999 ◽  
Vol 33 (1-4) ◽  
pp. 139-149 ◽  
Author(s):  
S. Matthies ◽  
L. Lutterotti ◽  
K. Ullemeyer ◽  
H.-R. Wenk
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Texture Analysis ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
New Approach ◽  
Texture Information ◽  
Sphere Covering ◽  
Low Symmetry

The recently developed RITA concept combines algorithms of the Rietveld structure analysis with those from modern texture analysis in order to get texture information from d-spacing diffraction spectra. It is demonstrated for a low symmetry material (quartz) and a minimum pole sphere covering by the measured spectra. The quality of the results underlines the efficiency of this new approach especially for time-of-flight neutron diffraction studies where access to the beam is limited. New interesting aspects for crystal structure refinement are discussed.

Application of quantitative texture analysis to Rietveld profile refinement of neutron diffraction patterns of a zircaloy sample

2001 ◽  
Vol 34 (3) ◽  
pp. 358-364 ◽  
Author(s):  
Y. C. Kim ◽  
B. S. Seong ◽  
J. H. Lee ◽  
E. J. Shin
Keyword(s):  
Neutron Diffraction ◽  
Texture Analysis ◽  
Rietveld Method ◽  
Structure Refinement ◽  
Polycrystalline Materials ◽  
Texture Information ◽  
Diffraction Patterns ◽  
The Individual ◽  
The Mathematical Model ◽  
Profile Refinement

The possibility of extending the Rietveld method to incorporate textured polycrystalline materials is demonstrated with a zircaloy sample. By assigning the pole densities obtained by separate texture analysis to the preferred orientation factors (POFs) in the mathematical model of the Rietveld method, good profile refinement results are achieved with the neutron diffraction patterns. The approach of predetermining the individual POF values from quantitative texture information can be used to improve refinement of other parameters related to the analysis of composite phases as well as to crystal structure refinement.

scholarly journals Texture and structural refinement using neutron diffraction data from molybdite (MoO3) and calcite (CaCO3) powders and a Ni-rich Ni50.7Ti49.30 alloy

2009 ◽  
Vol 24 (4) ◽  
pp. 315-326 ◽  
Author(s):  
Husin Sitepu
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Crystal Structures ◽  
Spherical Harmonic ◽  
Structure Refinement ◽  
Preferred Orientation ◽  
Composition Analysis ◽  
Crystal Structure Refinement ◽  
Structural Refinement ◽  
Spherical Harmonic Models

Preferred orientation or texture is a common feature of experimental powder patterns. The mathematics of two commonly used models for preferred orientation—the March-Dollase and the generalized spherical-harmonic models—is reviewed. Both models were applied individually to neutron powder data from uniaxially pressed molybdite (MoO3) and calcite (CaCO3) powders in Rietveld analyses, as well as the as-received powders. The structural refinement results are compared to single-crystal structures. The results indicate that reasonable refinement of crystal structures can be obtained using either the March model or generalized spherical-harmonic description. However, the generalized spherical-harmonic description provided better Rietveld fits than the March model for the molybdite and calcite. Therefore, the generalized spherical-harmonic description is recommended for correction of preferred orientation in neutron diffraction analysis for both crystal structure refinement and phase composition analysis. Subsequently, the generalized spherical-harmonic description is extended to crystal structure refinement of annealed and the aged polycrystalline Ni-rich Ni50.7Ti49.30 shape memory alloys.

Crystal Structure Refinement of the Oxygen-rich RCuO2+δ(R=Y and La) Delafossite by Neutron Diffraction

1998 ◽  
pp. 395-398 ◽  
Author(s):  
Kazuyuki Isawa ◽  
Yuji Yaegashi ◽  
Seiya Ogota ◽  
Mitsugu Nagano ◽  
Shiroshi Sudo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Structure Refinement ◽  
Crystal Structure Refinement

Iron in kornerupine; a57Fe Moessbauer spectroscopic study and comparison with single-crystal structure refinement

1999 ◽  
Vol 84 (4) ◽  
pp. 536-549 ◽  
Author(s):  
Edward S. Grew ◽  
Guenther J. Redhammer ◽  
Georg Amthauer ◽  
Mark A. Cooper ◽  
Frank C. Hawthorne ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Spectroscopic Study ◽  
Structure Refinement ◽  
Single Crystal Structure ◽  
Crystal Structure Refinement
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