scholarly journals Rietveld Quantitative Phase Analysis of OPC Clinkers, Cements and Hydration Products

2012 ◽  
Vol 74 (1) ◽  
pp. 169-209 ◽  
Author(s):  
M. A. G. Aranda* ◽  
A. G. De la Torre ◽  
L. Leon-Reina
Keyword(s):  
Phase Analysis ◽  
Quantitative Phase Analysis ◽  
Hydration Products ◽  
Quantitative Phase ◽  
Rietveld Quantitative Phase Analysis

Accuracy in Rietveld quantitative phase analysis with strictly monochromatic Mo and Cu radiations

2019 ◽  
pp. 374-384
Author(s):  
L. León-Reina ◽  
A. Cuesta ◽  
M. García-Maté ◽  
G. Álvarez-Pinazo ◽  
I. Santacruz ◽  
...  
Keyword(s):  
Phase Analysis ◽  
Quantitative Phase Analysis ◽  
Quantitative Phase ◽  
Rietveld Quantitative Phase Analysis

Quantitative phase analysis by combining the Rietveld and the whole-pattern decomposition methods

2002 ◽  
Vol 35 (4) ◽  
pp. 481-490 ◽  
Author(s):  
Cinzia Giannini ◽  
Antonietta Guagliardi ◽  
Roberto Millini
Keyword(s):  
Phase Analysis ◽  
Structural Model ◽  
Structural Information ◽  
Complex Structure ◽  
Quantitative Phase Analysis ◽  
Quantitative Phase ◽  
Absolute Scale ◽  
Pattern Decomposition ◽  
The Absolute ◽  
Rietveld Quantitative Phase Analysis

The Rietveld quantitative phase analysis of polycrystalline mixtures is a model-dependent method. The absence of any structural information about even one phase in the mixture prevents the application of the method; on the other hand, the availability of a structural model that is not sufficiently representative of real data can actually reduce the accuracy of the weight-fraction estimates. In these cases, when the experimental pattern of one (or more) pure phase(s) with unknown or imperfectly known crystal structure is available, the whole-pattern decomposition techniques can be applied to extract a list of `observed' amplitudes to be used instead of those calculated from the model. Observed and calculated amplitudes can be successfully combined to carry out the Rietveld quantitative phase analysis of even complex structure mixtures, provided that the initial amplitudes are correctly placed on the absolute scale. In the absence of any structural model, the absolute scale supplied by the Wilson plot technique can be applied. A general scheme of the method is proposed here; it has been implemented into the programQUANTOand tested on real zeolites mixtures. The method is basically independent of the program used for the extraction of the integrated intensities.

scholarly journals Rietveld quantitative phase analysis with molybdenum radiation

2014 ◽  
Vol 30 (1) ◽  
pp. 25-35 ◽  
Author(s):  
Ana Cuesta ◽  
Gema Álvarez-Pinazo ◽  
Marta García-Maté ◽  
Isabel Santacruz ◽  
Miguel A. G. Aranda ◽  
...  
Keyword(s):  
Phase Analysis ◽  
Building Materials ◽  
Mineralogical Composition ◽  
High Energy ◽  
Quantitative Phase Analysis ◽  
Reflection And Transmission ◽  
Complex Samples ◽  
Calcium Sulfoaluminate ◽  
Quantitative Phase ◽  
Rietveld Quantitative Phase Analysis

Building materials are very complex samples of worldwide importance; hence quantitative knowledge of their mineralogical composition is necessary to predict performances. Rietveld quantitative phase analysis (RQPA) allows a direct measurement of the crystalline phase contents of cements. We highlight in this paper the use of laboratory X-ray powder diffraction (LXRPD) employing high-energy radiation, molybdenum (Mo), for attaining the RQPA of cements. Firstly, we evaluate the accuracy of RQPA employing a commercial calcium sulfoaluminate clinker with gypsum. In addition to MoKα1 and MoKα1,2 radiations, Cu and synchrotron patterns are also analyzed for the sake of comparison. Secondly, the assessment of the accuracy of RQPA results obtained using different radiations (synchrotron, Mo, and Cu) and geometries (reflection and transmission) is performed by analyzing two well-known commercial samples. As expected, for LXRPD data, accuracy in the RQPA results improves as the irradiated volume increases. Finally, three very complex aged hydrated cements have been analyzed using MoKα1-LXRPD and Synchrotron-XRPD. The main overall outcome of this work is the benefit for RQPA of using strictly monochromatic MoKα1 radiation. Best laboratory results arise from MoKα1 data as the effective tested volume is much increased but peak overlapping is not swelled.

The Effect of Pressing Load on 8 mol% Yttria Stabilized Zirconia Grade 204NS-G

2020 ◽  
Vol 1010 ◽  
pp. 262-267
Author(s):  
Tinesha Selvaraj ◽  
Johar Banjuraizah ◽  
Shing Fhan Khor
Keyword(s):  
Crystal Structure ◽  
Heating Rate ◽  
Phase Analysis ◽  
Yttria Stabilized Zirconia ◽  
Quantitative Phase Analysis ◽  
Stabilized Zirconia ◽  
Compaction Characteristics ◽  
Quantitative Phase ◽  
Morphology Analysis ◽  
Rietveld Quantitative Phase Analysis

The aim of this study is to understand the compaction characteristics of as received granulated 8 mol% yttria-stabilized zirconia (8YSZ). The samples were compacted at different loads and sintered at 1550 °C with the heating rate of 5°C/min for 5 hours. The densification, morphology analysis and crystal structure of the sintered were compared. The densification of granulated 8YSZ achieved 67% as increasing pressing load (0.1 tonne to 0.4 tonne). Rietveld quantitative phase analysis demonstrates that the tetragonal-ZrO2 phase reduces in granulated 8YSZ. The amount of cubic-ZrO2 phase dramatically dropped for both granulated as the pressing load increased. From the morphology analysis, granulated sample found to be porous observed on the surface as compaction load applied. Compaction load has no significant effect on the densification of granule sintered 8YSZ in the current study. The maximum densification was only reached 67% by using granulated 8YSZ powder with 0.4 tonne pressing load.

Round robin on Rietveld quantitative phase analysis of Portland cements

2009 ◽  
Vol 42 (5) ◽  
pp. 906-916 ◽  
Author(s):  
L. León-Reina ◽  
A. G. De la Torre ◽  
J. M. Porras-Vázquez ◽  
M. Cruz ◽  
L. M. Ordonez ◽  
...  
Keyword(s):  
Phase Analysis ◽  
Round Robin ◽  
Quantitative Phase Analysis ◽  
Type I ◽  
Crystalline Phases ◽  
Quantitative Phase ◽  
Two Samples ◽  
Precision And Accuracy ◽  
Rietveld Quantitative Phase Analysis ◽  
Artificial Mixtures

Interlaboratory studies on the precision and accuracy of Rietveld quantitative phase analysis (R-QPA) of mixtures of crystalline phases have already been carried out. However, cement-related materials are samples of variable complexity, ranging from three phases in white Portland clinkers to more than eight phases in grey cements, that need to be specifically investigated. Here, the results are reported from a round robin on the R-QPA of cement-related materials from laboratories with experience in this type of analysis. The aim of the work was to evaluate the levels of precision and accuracy associated with Portland clinkers and cements. Two sets of samples have been investigated, artificial mixtures and commercial samples. Artificial mixtures were prepared by mixing (weighing) synthesized single-crystalline phases in the appropriate proportions: (i) white clinker (Ca3SiO5, Ca2SiO4and Ca3Al2O6) and (ii) grey cement (Ca3SiO5, Ca2SiO4, Ca3Al2O6, Ca4Al2Fe2O10, CaCO3and CaSO4·2H2O). These two samples were used to assess the accuracy and uncertainty of the procedure, as an expected mineralogical phase fraction, the `true mineralogical percentage', is available under the assumption of negligible non-diffracting contents. In order to assess the validity and limitations of the Rietveld-based approach for cement materials, three commercial samples were measured: (i) white Portland clinker, (ii) grey Portland clinker and (iii) a type-I grey Portland cement. The samples studied have been chosen in order to cover most of the different typologies of binders. Reproducibilities and general uncertainty values, with a level of confidence of 95%, are reported and discussed.

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