Investigations into the phase composition of zirconia-based sinters with an axial texture

2017 ◽  
Vol 50 (3) ◽  
pp. 769-775
Author(s):  
J. Podwórny ◽  
M. Staszewski ◽  
Józef Wojsa
Keyword(s):  
Phase Composition ◽  
Phase Analysis ◽  
Crystallographic Orientation ◽  
Volume Fraction ◽  
Mechanical Stresses ◽  
Quantitative Phase Analysis ◽  
Solid Samples ◽  
Statistical Point ◽  
X Ray ◽  
Quantitative Phase

Owing to the phase transition of the tetragonal form of ZrO2into the monoclinic one, caused by mechanical stresses, preparation of powder samples for quantitative phase analysis by the X-ray diffraction method should be avoided. The process of grinding of zirconia sinters leads to considerable changes in their phase composition. For this reason, a quantitative phase analysis should be conducted on solid samples not subjected to mechanical stresses, irrespective of problems appearing during experiments and analysis. One such problem is preferred crystallographic orientation (texture). This paper describes the influence of a preferred crystallographic orientation on the quantitative phase analysis conducted on solid samples and presents the results of an analysis in which corrections for uniaxial and multiaxial textures were applied. It was found that the examined samples had a very weak but nonzero multiaxial texture. The share of the randomly oriented fraction in the examined sinters was determined to beca94 vol.% and the share of the textured fractionca6 vol.%. From the statistical point of view, in the case of small amounts of the textured fraction, a correction on one distinguished crystallographic plane can overcome this problem. In the case of the slightly textured sinters of metering nozzles subjected to investigation here, the correction related to all the unique directions was statistically insignificant because the textured part corresponds to only a small volume fraction. However, corrections related to all texture axes considerably improve the fit of the calculated X-ray pattern with the experimental one and help to better characterize the examined materials.

A new method for quantitative phase analysis using X-ray powder diffraction: direct derivation of weight fractions from observed integrated intensities and chemical compositions of individual phases

2016 ◽  
Vol 49 (5) ◽  
pp. 1508-1516 ◽  
Author(s):  
Hideo Toraya
Keyword(s):  
Phase Analysis ◽  
Powder Diffraction ◽  
Volume Fraction ◽  
Quantitative Phase Analysis ◽  
Chemical Compositions ◽  
Chemical Formula ◽  
X Ray ◽  
Quantitative Phase ◽  
Integrated Intensity ◽  
The Individual

A new method for the quantitative phase analysis of multi-component polycrystalline materials using the X-ray powder diffraction technique is proposed. A formula for calculating weight fractions of individual crystalline phases has been derived from the intensity formula for powder diffraction in Bragg–Brentano geometry. The integrated intensity of a diffraction line is proportional to the volume fraction of a relevant crystalline phase in an irradiated sample, and the volume fraction, when it is multiplied with the chemical formula weight, can be related to the weight fraction. The structure-factor-related quantity in the intensity formula, when it is summed in an adequate 2θ range, can be replaced with the sum of squared numbers of electrons belonging to composing atoms in the chemical formula. Unit-cell volumes and the number of chemical formula units are all cancelled out in the formula. Therefore, the formula requires only single-measurement integrated intensity datasets for the individual phases and their chemical compositions. No standard reference material, reference intensity ratio or crystal structure parameter is required. A new procedure for partitioning the intensities of unresolved overlapped diffraction lines has also been proposed. It is an iterative procedure which starts from derived weight fractions, converts the weight fractions to volume fractions by utilizing additional information on material densities, and then partitions the intensities in proportion to the volume fractions. Use of the Pawley pattern decomposition method provides more accurate intensity datasets than the individual profile fitting technique, and it expands the applicability of the present method to more complex powder diffraction patterns. Test results using weighed mixture samples showed that the accuracy, evaluated by the root-mean-square error, is comparable to that obtained by Rietveld quantitative phase analysis.

Quantitative Phase Analysis by X-Ray Diffraction.

1966 ◽  
Vol 38 (12) ◽  
pp. 1741-1745 ◽  
Author(s):  
R. F. Karlak ◽  
D. S. Burnett
Keyword(s):  
Phase Analysis ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quantitative Phase

Quantitative Phase Analysis in Titanium by X-Ray Diffraction

1957 ◽  
Vol 1 ◽  
pp. 39-58
Author(s):  
Ralph H. Hiltz ◽  
Stanley L. Lopata
Keyword(s):  
Phase Analysis ◽  
Quantitative Phase Analysis ◽  
Metallographic Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quantitative Phase ◽  
Method Of Measurement ◽  
Graphic Methods

AbstractIn view of present difficulties encountered in met alio graphic methods of phase analysis of titanium and its alloys, the possibility of utilizing integrated X-ray intensities for phase analysis was investigated. Power Formula variables were calculated for titanium, and relative areas of three alpha and one beta peak were determined. Recorded X-ray intensities were obtained from a large number of titanium specimens. The recorded intensities were analyzed and the results compared with those from metallographic analysis. The errors in the method arising from the nature of titanium, texture and peak overlapping, were studied and where possible, compensated for by adjusting the method of measurement and calculation.

Phase composition and morphological analysis of human gallstones using IR spectroscopy, scanning electron microscopy and X-ray Rietveld analysis

2016 ◽  
Vol 231 (2) ◽  
Author(s):  
Samiran Pramanik ◽  
Soumen Ghosh ◽  
Arkaprovo Roy ◽  
Ramanuj Mukherjee ◽  
Alok Kumar Mukherjee
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Composition ◽  
Ir Spectroscopy ◽  
Rietveld Analysis ◽  
Quantitative Phase Analysis ◽  
Human Gallbladder ◽  
X Ray ◽  
Quantitative Phase ◽  
Scanning Electron

AbstractQuantitative phase composition and morphological characterization of 12 human gallbladder stones (GS1–GS12) retrieved from patients of eastern India have been carried out using IR-spectroscopy, powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). The FTIR spectra indicated that the primary composition of gallstones studied was cholesterol. X-ray powder diffraction study revealed cholesterol monohydrate (CHM) as the major crystalline phase in GS1–GS12. The Rietveld analysis showed that nine of the gallstones were composed exclusively of CHM, while the remaining three stones contained in addition to CHM, small amounts (4.2–10.6 wt%) of calcium carbonate as aragonite and vaterite. The crystallite size of CHM in GS1–GS12 varied between 82(6) and 249(3) nm. The SEM images of gallstones showed different crystal habits of CHM such as plates, thin rods, rectangular and hexagonal blocks, which resulted into different levels of agglomeration at the mesoscopic scale. Presence of numerous parasitic eggs with a typical muskmelon surface in three gallstones (GS2, GS7 and GS9) suggests possible association between the liver fluke infection and biliary stone formation in these patients. To the best of our knowledge, the study constitutes the first report of X-ray quantitative phase analysis of gallstones using the Rietveld methodology.

Accuracy in quantitative phase analysis of mixtures with large amorphous contents. The case of stoneware ceramics and bricks

2014 ◽  
Vol 47 (3) ◽  
pp. 835-846 ◽  
Author(s):  
Alessandro F. Gualtieri ◽  
Vincenzo Riva ◽  
Andrea Bresciani ◽  
Stefano Maretti ◽  
Marco Tamburini ◽  
...  
Keyword(s):  
Phase Analysis ◽  
Internal Standard ◽  
Quantitative Phase Analysis ◽  
Experimental Conditions ◽  
X Ray ◽  
Quantitative Phase ◽  
Factor Method ◽  
Counting Statistics ◽  
First Time ◽  
X Ray Absorption

For the first time, this work inspects the accuracy of quantitative phase analysis of both crystalline and amorphous components of stoneware tiles and bricks. A number of variables were considered: the nature of the internal standard, experimental conditions and counting statistics. The so-calledG-factor method has also been applied. The results of the X-ray powder diffraction analysis have been compared with the results obtained with optical microscopy and image analysis. Only the mixtures spiked with corundum and silicon yielded accurate weight estimates of the amorphous fraction, whereas the use of highly X-ray absorbing internal standards (such as fluorite, rutile and zincite) resulted in gross underestimations. In fact, microabsorption effects are found to drastically reduce the accuracy of the results when standards with linear X-ray absorption coefficients higher than 100 cm−1are employed. It was found that very low counting statistics reduced the calculated amorphous fractions in both bricks and stoneware tiles owing to partial masking of the major peak of the internal standard, namely corundum. The application of theG-factor method to the systems investigated was also evaluated. The results are poorer than those obtained using the internal standard.

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