scholarly journals Refining bimodal microstructure of materials with MSTRUCT

2014 ◽  
Vol 29 (S2) ◽  
pp. S35-S41 ◽  
Author(s):  
Z. Matěj ◽  
A. Kadlecová ◽  
M. Janeček ◽  
L. Matějová ◽  
M. Dopita ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Copper Sample ◽  
Bimodal Microstructure ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Angular Pressing ◽  
Crystallite Sizes ◽  
Diffraction Peaks

The possibilities of modelling the diffraction profiles from bimodal microstructure in computer program MSTRUCT are demonstrated on two examples. A special “Double Component” profile effect can be utilized for such problems. At first it was applied to an analysis of a mixture of two nanocrystalline anatase powders with different crystallite sizes and the relative ratio of both components was determined from X-ray diffraction data. In the second case study, diffraction peaks from a pure polycrystalline copper sample treated by equal channel angular pressing were fitted using a two-phase model of large recrystallized defect-free grains and ultrafine crystallites with high dislocation density. The method is shown to be suitable for determination of the relative fraction of the microstructural components as well as other parameters (e.g. dislocation density).

scholarly journals Determination of Dislocation Density and Correlation Length of Si, Ti, Au and Zno on Ge by Peak Profile

2021 ◽  
Author(s):  
Ahmet Kürşat Bilgili ◽  
Rabia ÇAĞATAY ◽  
Hasan Celal DERVİŞOĞLU ◽  
Mustafa Kemal ÖZTÜRK
Keyword(s):  
Dislocation Density ◽  
Correlation Length ◽  
Iteration Step ◽  
X Ray Diffraction ◽  
Dense Region ◽  
X Ray ◽  
Good Accordance ◽  
Gauss Function ◽  
Diffraction Peaks

Abstract In this study, X-ray diffraction peaks of Si, Ti, Au and ZnO grown on Ge substrate with thickness of 500 nm by using sputtering method are analyzed to determine correlation length and dislocation density. It is seen that in most dense region of peaks, peak behaviour is in accordance with Gauss function. Right and left tails of peaks are in good accordance with q3 law. For randomized dislocations, obeying q3 law is typical and they can be monitored with w-scans by using open detectors. Whole profile is fitted with a limited dislocation dispersion. Edge dislocation density and correlation length are determined in the degree of 1010cm-2 and 103 nm, respectively. In order to gain these values, semi-experimental equations in Kragner method are used. For making a good fit, fit iteration step is taken as 9x106.

scholarly journals Investigations on historical monuments’ deterioration through chemical and isotopic analyses: an Italian case study

2021 ◽  
Author(s):  
Maria Ricciardi ◽  
Concetta Pironti ◽  
Oriana Motta ◽  
Rosa Fiorillo ◽  
Federica Camin ◽  
...  
Keyword(s):  
Potassium Nitrate ◽  
Sewage Water ◽  
X Ray Diffraction ◽  
Italian Case ◽  
Historical Monuments ◽  
Isotopic Analyses ◽  
Historic Centre ◽  
The Church

AbstractIn this paper, we analysed the efflorescences present in the frescos of a monumental complex named S. Pietro a Corte situated in the historic centre of Salerno (Campania, Italy). The groundwater of the historic centre is fed by two important streams (the Rafastia and the Fusandola) that can be the sources of water penetration. The aims of this work are to (i) identify the stream that reaches the ancient frigidarium of S. Pietro a Corte and (ii) characterize the efflorescences on damaged frescos in terms of chemical nature and sources. In order to accomplish the first aim, the water of the Rafastia river (7 samples) and the water of the Fusandola river (7 samples) were analysed and compared with the water of a well of the Church (7 samples). The ionic chromatography measurements on the water samples allowed us to identify the Rafastia as the river that feeds the ancient frigidarium of S. Pietro a Corte. To investigate the nature and the origin of the efflorescences (our second aim), anionic chromatography analyses, X-ray diffraction measurements, and the isotopic determination of nitrogen were performed on the efflorescences (9 samples) and the salts recovered from the well (6 samples). Results of these analyses show that efflorescences are mainly made of potassium nitrate with a δ15N value of + 9.3 ± 0.2‰. Consequently, a plausible explanation for their formation could be the permeation of sewage water on the walls of the monumental complex.

Chemical sensing failed by aggregation-caused quenching? A case study enables liquid/solid two-phase determination of N2H4

2021 ◽  
Vol 415 ◽  
pp. 128975
Author(s):  
Xiangqian Li ◽  
Mengqing Li ◽  
Yuze Chen ◽  
Gongxi Qiao ◽  
Qian Liu ◽  
...  
Keyword(s):  
Chemical Sensing ◽  
Phase Determination ◽  
Two Phase

X-ray diffraction analysis of stacking and twin faults in f.c.c. metals: a revision and allowance for texture and non-uniform fault probabilities

2000 ◽  
Vol 33 (2) ◽  
pp. 296-306 ◽  
Author(s):  
L. Velterop ◽  
R. Delhez ◽  
Th. H. de Keijser ◽  
E. J. Mittemeijer ◽  
D. Reefman
Keyword(s):  
Diffraction Analysis ◽  
Line Profile ◽  
Intensity Distribution ◽  
Original Description ◽  
Powder Pattern ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Line Profile ◽  
Crystallite Sizes ◽  
Diffraction Peaks

A revision is presented of the original description by Warren [X-ray Diffraction, (1969), pp. 275–298. Massachusetts: Addison-Wesley] of the intensity distribution of powder-pattern reflections from f.c.c. metal samples containing stacking and twin faults. The assumptions (in many cases unrealistic) that fault probabilities need to be very small and equal for all fault planes and that the crystallites in the sample have to be randomly oriented have been removed. To elucidate the theory, a number of examples are given, showing how stacking and twin faults change the shape and position of diffraction peaks. It is seen that significant errors may arise from Warren's assumptions, especially in the peak maximum shift. Furthermore, it is explained how to describe powder-pattern reflections from textured specimens and specimens with non-uniform fault probabilities. Finally, it is discussed how stacking- and twin-fault probabilities (and crystallite sizes) can be determined from diffraction line-profile measurements.

Determination of Tricalcium Silicates Crystal Forms in Belite-Barium Calcium Sulphoaluminate Cement

2014 ◽  
Vol 541-542 ◽  
pp. 204-208
Author(s):  
Yan Ting Zhao ◽  
Xi Chen ◽  
Ling Chao Lu ◽  
Yong Bo Huang ◽  
Jie Zhang
Keyword(s):  
Cement Clinker ◽  
X Ray Diffraction ◽  
Crystal Forms ◽  
Sulphoaluminate Cement ◽  
Cement System ◽  
Calcium Sulphoaluminate ◽  
Diffraction Peaks ◽  
Method Of Extraction ◽  
Calcium Sulphoaluminate Cement

Chemical method of extraction was adopted in the study, and aqueous solution of potassium hydroxide and sucrose (KOSH) was used to obtain the clinker rich in silicate phases (alite and belite) in order to get the crystal forms of tricalcium silicates (C3S) in the belite-barium calcium sulphoaluminate cement clinker. The crystal forms of C3S were finally determined by XRD (X-ray diffraction) spectrums through its characteristic windows of the diffraction spectrums. Results shows that, C3S exists in the innovative cement system mainly in the form of M1; C2.75B1.25A3can completely dissolve in KOSH solution while its dissolution is inhibited in the cement system; after KOSH treatment, diffraction peaks of C4AF disappear totally and peaks of C3A has weakened to great extent; for the cement clinker, the clinker ground for 90min has the best extraction rate.

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