scholarly journals The effect of data quality and model parameters on the quantitative phase analysis of X-ray diffraction data by the Rietveld method

2021 ◽  
Vol 54 (3) ◽  
Author(s):  
Matthew R. Rowles

The quality of X-ray powder diffraction data and the number and type of refinable parameters have been examined with respect to their effect on quantitative phase analysis (QPA) by the Rietveld method using data collected from two samples from the QPA round robin [Madsen, Scarlett, Cranswick & Lwin (2001). J. Appl. Cryst. 34, 409–426]. From the analyses of these best-case-scenario specimens, a series of recommendations for minimum standards of data collection and analysis are proposed. It is hoped that these will aid new QPA-by-Rietveld users in their analyses.

2006 ◽  
Vol 9 (4) ◽  
pp. 369-374 ◽  
Author(s):  
Terezinha Ferreira de Oliveira ◽  
Roberto Ribeiro de Avillez ◽  
Eugenio Kahn Epprecht ◽  
Joaquim Carlos Barbosa Queiroz

2017 ◽  
Vol 898 ◽  
pp. 2054-2059
Author(s):  
Yan Ling Gan ◽  
Su Ping Cui ◽  
Ya Li Wang ◽  
Hong Xia Guo

For cement-matrix materials, the microstructure plays a vital important role in the research. Recently, quantitative phase analysis of cementitious materials can be performed using the Rietveld method by fitting the calculated X-ray diffraction (XRD) profile with the observed one. The aim of this paper is to further perform the quantitative analysis by the Rietveld method and discuss the influence of testing factors on the Rietveld quantitative phase analysis. The factors included the collection range of pattern, step size and the scan time of per step. In this study, the chemical composition of the samples was determined by X-ray fluorescence (XRF) spectrometry. And their phase composition was calculated by X-ray powder diffraction and Rietveld analysis. The results showed that the collection range of pattern depended on the tested materials , and the scanning range should include the main diffraction peak of the sample. Smaller step size and longer scan time of each step made the fitting factor smaller, also the calculated pattern coincided with the measured pattern, better enhance the precision of the analyses.


2004 ◽  
Vol 443-444 ◽  
pp. 45-50 ◽  
Author(s):  
B. Peplinski ◽  
R. Kleeberg ◽  
J. Bergmann ◽  
J. Wenzel

On the basis of data gathered in connection with a certification project, problems were investigated that impair the accuracy of quantitative phase analyses (QPA) using the Rietveld method. Some mechanisms were elucidated by which insufficient counting statistics of the diffraction data or inappropriate data handling and refinement strategy influence the QPA results.


2018 ◽  
Vol 212 ◽  
pp. 51-60 ◽  
Author(s):  
Guilherme A. Calligaris ◽  
Thais L.T. da Silva ◽  
Ana Paula B. Ribeiro ◽  
Adenilson O. dos Santos ◽  
Lisandro P. Cardoso

2014 ◽  
Vol 881-883 ◽  
pp. 1241-1244
Author(s):  
Wei Jin Zeng ◽  
Chao Zeng ◽  
Wei He

The quantitative phase analyses of a slag have been successfully carried out by using both of the full-profile Rietveld and RIR methods from X-ray powder diffraction data. The qualitative phase analysis indicates that the slag contains mayenite (CaO)12(Al2O3)7, olivine Ca2(SiO4), gehlenite Ca2Al (AlSiO7), lemite Ca2(SiO4) and hibonite CaO(Al2O3)6. The quantitative analysis from Rietveld refinement shows that the weight concentrations of mayenite, olivine, gehlenite, lemite and hibonite for the slag are 48.8(4) wt.%, 32.2(5) wt.%, 11.0(9) wt.%, 6.2(1.1) wt.% and 1.8 (1.2) wt.%, respectively. The quantitative phase analysis results obtained by Rietveld method are more precise then those by RIR method.


2004 ◽  
Vol 37 (1) ◽  
pp. 8-13 ◽  
Author(s):  
A. F. Gualtieri ◽  
G. Brignoli

The accuracy of the weight fractions calculated with the Rietveld method for various polycrystalline systems using data collected for very short times (5–45 min) with an RTMS (real-time multiple strip) detector was verified. The weight estimates were compared with those obtained using the same conventional Bragg–Brentano geometry, a gas proportional detector and a 13 h data acquisition. The analysed samples were monophasic and polyphasic mixtures with different degrees of complexity: the standard corundum NIST 676; a sample (labelled 1g) provided as a standard sample for the IUCr CPD Quantitative Phase Analysis Round Robin; a natural pyroclastic rock from Riano (Rome, Italy) containing zeolitic minerals and a glass phase; and a hydraulic lime. The results of the refinements show estimated weights consistent with both those obtained with a gas proportional detector and with the nominal values, indicating a very good accuracy. Only when variable slits are used, the accuracy of the estimated weights slightly decreases. The outcome of this work is a very important step forward towards fast and accurate QPA for production control and quality management, obtained by combining the use of a rapid detector and existing user-friendly software.


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