scholarly journals Quantitative firing transformations of a triaxial ceramic by X-ray diffraction methods

Cerâmica ◽  
2014 ◽  
Vol 60 (356) ◽  
pp. 524-531 ◽  
Author(s):  
M. S. Conconi ◽  
M. R. Gauna ◽  
M. F. Serra ◽  
G. Suarez ◽  
E. F. Aglietti ◽  
...  
Keyword(s):  
Glassy Phase ◽  
Internal Standard ◽  
Rietveld Analysis ◽  
Internal Standard Method ◽  
X Ray Diffraction ◽  
Spinel Type ◽  
X Ray ◽  
Porosity Evolution ◽  
Diffraction Patterns ◽  
Low Crystalline

The firing transformations of traditional (clay based) ceramics are of technological and archeological interest, and are usually reported qualitatively or semiquantitatively. These kinds of systems present an important complexity, especially for X-ray diffraction techniques, due to the presence of fully crystalline, low crystalline and amorphous phases. In this article we present the results of a qualitative and quantitative X-ray diffraction Rietveld analysis of the fully crystalline (kaolinite, quartz, cristobalite, feldspars and/or mullite), the low crystalline (metakaolinite and/or spinel type pre-mullite) and glassy phases evolution of a triaxial (clay-quartz-feldspar) ceramic fired in a wide temperature range between 900 and 1300 ºC. The employed methodology to determine low crystalline and glassy phase abundances is based in a combination of the internal standard method and the use of a nanocrystalline model where the long-range order is lost, respectively. A preliminary sintering characterization was carried out by contraction, density and porosity evolution with the firing temperature. Simultaneous thermo-gravimetric and differential thermal analysis was carried out to elucidate the actual temperature at which the chemical changes occur. Finally, the quantitative analysis based on the Rietveld refinement of the X-ray diffraction patterns was performed. The kaolinite decomposition into metakaolinite was determined quantitatively; the intermediate (980 ºC) spinel type alumino-silicate formation was also quantified; the incongruent fusion of the potash feldspar was observed and quantified together with the final mullitization and the amorphous (glassy) phase formation.The methodology used to analyze the X-ray diffraction patterns proved to be suitable to evaluate quantitatively the thermal transformations that occur in a complex system like the triaxial ceramics. The evaluated phases can be easily correlated with the processing variables and materials properties. These correlations can be employed for materials characterization, design and processing control.

Crystallization of simonkolleite (Zn5Cl2(OH)8 ∙ H2O) in powder samples prepared for mineral composition analysis by quantitative X-ray diffraction (QXRD)

Nafta-Gaz ◽  
2021 ◽  
Vol 77 (5) ◽  
pp. 293-298
Author(s):  
Urszula Zagórska ◽  
◽  
Sylwia Kowalska ◽  
Keyword(s):  
Quantitative Analysis ◽  
Internal Standard ◽  
Mineralogical Composition ◽  
Hydrocarbon Exploration ◽  
Composition Analysis ◽  
Internal Standard Method ◽  
X Ray Diffraction ◽  
Method Error ◽  
X Ray ◽  
Significant Difference

The analysis of mineralogical composition by quantitative X-ray diffraction (QXRD) is one of the standard research methods used in hydrocarbon exploration. In order to improve it and to obtain better results, the methodology of quantitative analysis used at Well Logging Department is being periodically (more or less) modified. After the introduction of the improvements, comparative analyses were performed on archival samples. Reflections from an unidentified phase which did not occur in the tested Rotliegend sandstone samples were noticed on X-ray diffractograms of archival samples. Reflections of a mineral called simonkolleite were identified in the X-ray diffraction database. Chemically it is a hydrated zinc chloride of the formula: Zn5Cl2(OH)8 × H2O. Analysis of the composition of samples in which simonkolleite crystallised, indicated that the mineral is being formed in the result of the slow reaction of zinc oxide with halite (NaCl) and water vapour. An attempt was made to determine the influence of the presence of this mineral on the results of the quantitative analysis of mineralogical composition. The above methodology was applied on a group of ten samples. The results of the quantitative analysis conducted for archival samples stored with added zincite standard containing simonkolleite and for new, freshly grinded (without artifact) samples were compared. The comparison of the obtained results showed a slight influence of this mineral on the quantitative composition of the remaining components. The difference between the results usually did not exceed the method error. At the same time a significant difference in the calculated content of the internal standard was noted – on average 1% less in archival than in new samples. This shows that the reaction occurring in the archival samples will affect the evaluation of the quality of the obtained quantitative analysis, at the same time excluding the possibility of determining the rock’s amorphous substance content with the internal standard method.

X-ray powder diffraction analysis of the heteropoly-molybdate (MoO2)0.5PMo14O42

2003 ◽  
Vol 18 (3) ◽  
pp. 236-239 ◽  
Author(s):  
L. Marosi ◽  
J. Cifré ◽  
C. Otero Areán
Keyword(s):  
Catalytic Activity ◽  
Diffraction Analysis ◽  
Computer Modeling ◽  
Powder Diffraction ◽  
Rietveld Analysis ◽  
Nitrogen Atmosphere ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns

The new heteropoly blue compound (MoO2)0.5PMo14O42, which is relevant in the context of catalytic activity of heteropoly-molybdates, was prepared by controlled thermolysis of (NH4)3PMo12O40 at 730 K in a nitrogen atmosphere. Powder X-ray diffraction analysis showed that this compound has a cubic unit cell, space group Pn3m (No. 224), with ao=11.795(2) Å, Z=2 and DXR=4.2466 g cm−3. Computer modeling and Rietveld analysis of powder diffraction patterns led to a proposed structure of the corresponding Keggin-cage unit PMo14O42.

scholarly journals Firing transformations of an argentinean calcareous commercial clay

Cerâmica ◽  
2013 ◽  
Vol 59 (350) ◽  
pp. 254-261 ◽  
Author(s):  
M. F. Serra ◽  
M.S. Conconi ◽  
G. Suarez ◽  
E. F. Agietti ◽  
N. M. Rendtorff
Keyword(s):  
Internal Standard ◽  
Ceramic Materials ◽  
Thermal Treatments ◽  
Quartz Content ◽  
Spinel Type ◽  
Porosity Evolution ◽  
Phase Quantification ◽  
Alumino Silicate ◽  
Diffraction Patterns ◽  
Sintering Characteristics

Mineralogical transformations caused by firing are usually studied by XRD methods only semi-quantitatively. In this work the original mineral disappearance and the neo-mineralization were evaluated quantitatively. Furthermore an indirect non crystalline phase quantification was performed under 1100 ºC was also carried out using the quartz content as internal standard. This study specifically discusses the behavior of an Argentinean white calcareous earthenware commercial when subjected to traditional ceramic firing, besides the technological importance of this particular material, it acts as a model for other clay based ceramic materials. Materials were subjected to thermal treatments between 700 ºC and 1100 ºC. A preliminary sintering characterization was carried out by contraction and porosity evolution. Simultaneous thermogravimetric and differential thermal analysis (TG-DTA) was carried out to elucidate the actual temperature at which the chemical changes occur. Finally, a quantitative analysis based on the Rietveld refinement of the X-ray diffraction patterns was performed to characterize the crystalline phases present in both the clay and in the materials obtained after different thermal treatments. The actual chemical reactions are proposed. The phases identified after firing at traditional working temperature (1040 ºC) are quartz, plagioclase, and the Spinel type alumino-silicate, accompanied by the non-diffracting un-reacted metakaolin and some amount of amorphous glassy phase. At intermediate temperatures (900 ºC) the presence of gehlenite was also detected. The carbonates (calcite and dolomite) presence and decomposition were also evaluated and demonstrated to determine the sintering characteristics of this material.

Microstructure Formation of Al-Fe-Mn-Si Aluminides by Pressure-Assisted Reactive Sintering of Elemental Powder Mixtures

2009 ◽  
Vol 68 ◽  
pp. 21-33 ◽  
Author(s):  
Alfredo Flores ◽  
J.A. Toscano ◽  
S. Rodríguez ◽  
A. Salinas R. ◽  
Enrique Nava-Vázquez
Keyword(s):  
Microstructural Characterization ◽  
Rietveld Analysis ◽  
Reactive Sintering ◽  
X Ray Diffraction ◽  
Microstructure Formation ◽  
Powder Mixtures ◽  
X Ray ◽  
Intermediate Phases ◽  
Diffraction Patterns ◽  
Metallurgical Reactions

This paper presents the results of an investigation aimed at understanding microstructure formation of Al-Fe-Mn-Si intermetallics during pressure-assisted reactive sintering of elemental powders. The proportion of elements was selected such that the composition of the product was 55 wt % Al, 17 wt % Si, 14 wt % Mn, and 14 wt % Fe. Experiments were conducted at temperatures between 600 and 800°C, using compaction stresses of up to 20 MPa. Rietveld analysis of x-ray diffraction patterns of fully processed samples showed that the powders were transformed into a mixture of Al9FeMnSi and Al9FeMn2Si phases. However, as temperature and pressure were increased, the Al9FeMnSi phase was transformed into the Al9FeMn2Si phase. Differential Thermal Analysis, as well as microstructural characterization by scanning electron microscopy and x-ray diffraction, showed that these intermetallics do not form directly from the powder mixtures. Rather, they are the result of metallurgical reactions between a molten Al-Si solution and various intermediate phases formed during reactive sintering.

Review of X-ray powder diffraction data of rhombohedral bismuth tri-iodide

1996 ◽  
Vol 11 (2) ◽  
pp. 91-96 ◽  
Author(s):  
L. Keller ◽  
D. Nason
Keyword(s):  
Rietveld Refinement ◽  
Room Temperature ◽  
Internal Standard ◽  
Standard Technique ◽  
Rietveld Analysis ◽  
Lattice Parameter ◽  
Parameter Determination ◽  
Data Set ◽  
X Ray ◽  
Diffraction Patterns

Single crystals of rhombohedral bismuth tri-iodide grown by physical vapor transport are possible candidates for room-temperature detectors. Previously reported, low angle reflections in X-ray diffraction patterns of various BiI3 starting powders are attributed to the BiI3 structure from Rietveld analysis. Accordingly, the lattice parameters of stoichiometric BiI3 are determined as a0=7.5192±0.0003 Å and c0=20.721±0.004 Å at room temperature. It also appears that lattice parameter determination using Rietveld refinement can lead to significant errors if experimental aberrations are present and their nature and magnitude are unknown. A modified internal standard technique is applied to the data set prior to Rietveld refinement for more reliable lattice parameter determination.

The Use of Reference Intensity Ratios in X-Ray Quantitative Analysis

1992 ◽  
Vol 7 (4) ◽  
pp. 186-193 ◽  
Author(s):  
Robert L. Snyder
Keyword(s):  
Quantitative Analysis ◽  
Standard Method ◽  
Amorphous Material ◽  
Internal Standard ◽  
Rietveld Analysis ◽  
Internal Standard Method ◽  
X Ray ◽  
Quantitative Results ◽  
Matching Procedure ◽  
Standardless Analysis

AbstractEach of the RIR based methods for carrying out quantitative X-ray powder diffraction analysis are described and a consistent set of notation is developed. The so called “standardless” analysis procedures are shown to be a special case of the internal-standard method of analysis where the normalizing assumption is used. All analytical methods, other than the Rietveld whole pattern matching procedure, require the use of explicitly measured standards, typically in the form of RIR values. However, if only semi-quantitative results can be tolerated, the standards may be obtained by using published RIR and relative intensity values. The exciting new techniques of whole pattern fitting and Rietveld constrained quantitative analysis are also described in RIR notation and shown also to be forms of the internal-standard method with the normalization assumption. The quantitative results obtained from Rietveld quantitative analysis are derived from computed standards in the form of computed, normalized, RIRN values. The normalization assumption in Rietveld analysis allows the exclusive use of computed standards and comes as close to a “standardless” analysis as one can achieve: relying on the absence of amorphous material and on the validity of the structural models. Relationships are given for obtaining quantitative analysis from these RIRN values obtainable from the least-squares scale factors.

Intermetallic Hydrides Based on (Zr-Ti)(Fe-Cr)2 Type of Compounds

2006 ◽  
Vol 514-516 ◽  
pp. 666-671 ◽  
Author(s):  
Sofoklis S. Makridis ◽  
C. Christodoulou ◽  
Mary Konstantakou ◽  
Th.A. Steriotis ◽  
M. Daniil ◽  
...  
Keyword(s):  
Hydrogen Pressure ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Paramagnetic Behaviour ◽  
Diffraction Patterns ◽  
Microstructural Studies ◽  
Dominant Phase

In this work, the (Zr-Ti)(Fe-Cr)2 based compounds have been synthesized while charging-discharging hydrogen ability has been examined. Relatively low hydrogen pressure has been used for the hydrogenation of the samples. After following the discharging procedure, a high desorbed amount of hydrogen ~180 (ml of H2)/(gr of the alloy) has been measured on the first 15 min by using a volumetric device. The crystal structure has been analyzed by means of x-ray diffraction (XRD) while a Rietveld analysis has been performed on the x-ray diffraction patterns and the characteristic MgZn2 type of structure has found to be the dominant phase in both compounds. The scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX) have been used for microstructural studies and quantitative analysis, respectively. Magnetic measurements have been performed on the samples and a paramagnetic behaviour has found to be at room temperature.

Quantitative X-Ray Diffraction Analysis of Anhydrous and Hydrated Portland Cement - Part 2: Computer-Based Methods

2015 ◽  
Vol 1087 ◽  
pp. 498-503 ◽  
Author(s):  
Duong D. Nguyen ◽  
Liam Devlin ◽  
Pramod Koshy ◽  
Charles C. Sorrell
Keyword(s):  
Portland Cement ◽  
Rietveld Method ◽  
Internal Standard ◽  
Xrd Analysis ◽  
Internal Standard Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
External Standard ◽  
Computer Based ◽  
General Aspects

The present work reviews current practices in quantitative XRD analysis of anhydrous and hydrated Portland cement. While Part 1 of this two-part work reviews the conventional internal standard method and the reference intensity ratio (RIR) method, Part 2 reviews the more commonly used computer-based methods, which include the Rietveld method (with or without internal standard) and the G-factor method (with external standard). Further, some critical general aspects of the experimental procedures that affect the accuracy of the analysis are discussed.

FULLPAT: a full-pattern quantitative analysis program for X-ray powder diffraction using measured and calculated patterns

2002 ◽  
Vol 35 (6) ◽  
pp. 744-749 ◽  
Author(s):  
Steve J. Chipera ◽  
David L. Bish
Keyword(s):  
Quantitative Analysis ◽  
Matrix Effects ◽  
Internal Standard ◽  
Solid Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Phases ◽  
Quantitative Analysis Method ◽  
Diffraction Patterns ◽  
User Intervention

FULLPATis a quantitative X-ray diffraction methodology that merges the advantages of existing full-pattern fitting methods with the traditional reference intensity ratio (RIR) method. Like the Rietveld quantitative analysis method, it uses complete diffraction patterns, including the background. However,FULLPATcan explicitly analyze all phases in a sample, including partially ordered or amorphous phases such as glasses, clay minerals, or polymers. Addition of an internal standard to both library standards and unknown samples eliminates instrumental and matrix effects and allows unconstrained analyses to be conducted by direct fitting of library standard patterns to each phase in the sample. Standard patterns may include data for any solid material including glasses, and calculated patterns may also be used. A combination of standard patterns is fitted to observed patterns using least-squares minimization, thereby reducing user intervention and bias.FULLPAThas been coded into MicrosoftEXCELusing standard spreadsheet functions.

The Application of X-Ray Diffraction for Glass Batch Homogeneity Determination

1981 ◽  
Vol 25 ◽  
pp. 379-382
Author(s):  
H. S. Kim ◽  
C. I. Cohen
Keyword(s):  
Sample Preparation ◽  
Glass Batch ◽  
Reference Sample ◽  
Internal Standard ◽  
Data Sets ◽  
Internal Standard Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Integrated Intensity ◽  
Quantitative Analyses

AbstractAn X-ray diffraction (XRD) technique is employed to determine the presence or absence of crystalline phases in glass batch and to determine its homogeneity qualitatively and quantitatively.Sample preparation problems are discussed, and promising techniques for sample preparation are presented. Qualitative batch homogeneity determination is accomplished by comparing the integrated intensity of a particular reflection of the reference sample to that of the unknown sample. Quantitative batch determination is accomplished by using the internal standard method. Three replicated data sets indicate that the standard deviation of kaolinite and colemanite are higher than those of quartz and calcite. However, the overall data from the quantitative analyses lie within an acceptable range of precision and accuracy.

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