scholarly journals Interlamellar Space Configuration under Variable Environmental Conditions in the Case of Ni-Exchanged Montmorillonite: Quantitative XRD Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Marwa Ammar ◽  
Walid Oueslati ◽  
Nejmeddine Chorfi ◽  
Hafsia Ben Rhaiem
Keyword(s):  
Layer Structure ◽  
Theoretical Models ◽  
Xrd Analysis ◽  
Retention Mechanism ◽  
X Ray Diffraction ◽  
Host Materials ◽  
Space Organization ◽  
Interlamellar Space ◽  
Xrd Patterns ◽  
Low Charge

Interlamellar space organization of low-charge montmorillonite was studied by modeling of X-ray diffraction (XRD) patterns recorded under controlled relative humidity (RH) conditions on Ni saturated specimens. The quantitative XRD investigation, based on an indirect method consisting of the comparison of experimental00lreflections with the other calculated from structural models, is used to characterize eventual nanostructural changes alongc*axis of Ni-exchanged montmorillonite. This method allowed us to determine, respectively, the relative layer types contribution, the layer thickness, nanoconfiguration of the interlamellar space, and position, amount, and organization of water molecules and exchangeable cations. Obtained theoretical models exhibit heterogeneous hydration state which is the dominating character detected all over studied cycles. Along RH cycle a modification in the main structure of the host materials is performed and the presence of a mixed layer structure (MLS) is noted. The hydration hysteresis at the low and the high RH range can be explained by fluctuations in the water retention mechanism and hydration heterogeneities created within the smectite crystallite.

scholarly journals Crystalline Swelling Process of Mg-Exchanged Montmorillonite: Effect of External Environmental Solicitation

2018 ◽  
Vol 2018 ◽  
pp. 1-18
Author(s):  
Marwa Ammar ◽  
Walid Oueslati
Keyword(s):  
Theoretical Models ◽  
Retention Mechanism ◽  
X Ray Diffraction ◽  
Interlayer Water ◽  
Hydration Properties ◽  
Crystalline Swelling ◽  
Low Charge ◽  
Interlayer Water Molecule

This work reports characterization of the possible effects that might distress the hydration properties of Mg-exchanged low-charge montmorillonite (SWy-2) when it undergoes external environmental solicitation. This perturbation was created by an alteration of relative humidity rates (i.e., RH%) over two hydration-dehydration cycles with different sequence orientations. Structural characterization is mainly based on the X-ray diffraction (XRD) profile-modeling approach achieved by comparing the “in situ” obtained experimental 00l reflections with other ones calculated from theoretical models. This method allows assessing the evolution of the interlayer water retention mechanism and the progress of diverse hydration state’s contributions versus external strain. Obtained results prove that the hydration behavior of the studied materials is strongly dependent on the RH sequence orientation which varied over cycles. The interlayer organization of Mg-exchanged montmorillonite (i.e., SWy-2-Mg) is characterized by a heterogeneous hydration behavior, which is systematically observed at different stages of both cycles. By comparing the interlayer water process evolution of Mg-exchanged montmorillonite with the observed SWy-2-Ni sample hydration behaviors, a same hysteresis thickness characterized by obvious fluctuations of interlayer water molecule abundances is observed. Nevertheless, in the case of Hg and Ba-saturated montmorillonite, the retention water process versus the applied cycles was steadier comparing with Mg ions.

Analysis of Selected Area Diffraction Patterns With Winjade

1998 ◽  
Vol 4 (S2) ◽  
pp. 342-343 ◽  
Author(s):  
S. D. Walck ◽  
P. Ruzakowski-Athey
Keyword(s):  
Single Phase ◽  
Xrd Analysis ◽  
Analysis Program ◽  
X Ray Diffraction ◽  
Program Module ◽  
Vast Number ◽  
One Dimensional ◽  
X Ray ◽  
Diffraction Patterns ◽  
Xrd Patterns

The analysis of Selected Area Diffraction (SAD) patterns that are collected from a single phase material having sufficient crystallites to provide continuous rings is relatively straightforward. However, when this condition is not met and there may be several phases present having rings of a spotty nature, the pattern is complex and can be quite difficult to analyze manually because of the vast number of discrete spots. WinJade from MDI is an X-ray diffraction (XRD) analysis program with an Electron Diffraction Program Module (EDPM) that can be used to aid in the analysis of SAD patterns. The EDPM produces Integrated Circular Density Plots (ICDP), which are one-dimensional intensity profiles plotted as a function of equivalent XRD 20 values or crystal d-spacings. These ICDP's can be overlayed with XRD patterns or with reference lines from the NIST and JCPDS crystalline databases for direct comparisons.

EFFECT OF GAMMA IRRADIATION ON YBa2Cu3O7-δ HIGH TEMPERATURE SUPERCONDUCTORS

2008 ◽  
Vol 22 (27) ◽  
pp. 2699-2707 ◽  
Author(s):  
SAADAT A. SIDDIQI ◽  
RABIA SIDDIQUI ◽  
SALAMAT ALI
Keyword(s):  
Gamma Irradiation ◽  
Structural Changes ◽  
High Temperature Superconductors ◽  
Secondary Phase ◽  
Xrd Analysis ◽  
Theoretical Explanation ◽  
X Ray Diffraction ◽  
Lattice Constants ◽  
Xrd Patterns ◽  
Experimental Findings

Samples of YBa 2 Cu 3 O 7-δ superconducting ceramic were prepared and characterized by resistivity measurements using the four probe method and structural analysis using X-ray diffraction (XRD). XRD-patterns show the presence of orthorhombic Y -123 phase with a small fraction of secondary phase, YBa 2 Cu 3 O 5. Samples were irradiated with gamma (γ) rays using Co 60 source with five successive doses of 2.5 Mrad. A monotonic increase in the Tc0 value was observed for radiation dosage up to 10 Mrad. When exposed to even higher γ-doses, the Tc0 value leveled off at a saturation value or decreased. XRD-analysis shows slightly changed values of the lattice constants and a mild shift of diffraction peaks towards a lower 2θ value. These observations indicate structural changes in YBa 2 Cu 3 O 7-δ induced upon gamma irradiation. The present work describes our experimental findings and attempts to offer a theoretical explanation for the effects observed.

Synthesis and Optical Properties of Eu3+ Doped NaYF4 and KYF4 Micro/Nanocrystals

2016 ◽  
Vol 16 (4) ◽  
pp. 3857-3860 ◽  
Author(s):  
Siling Guo ◽  
Chunyan Cao ◽  
Renping Cao
Keyword(s):  
Optical Properties ◽  
Emission Spectra ◽  
Local Environment ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Two Samples ◽  
Xrd Patterns ◽  
The Eu

Through a hydrothermal method, 1 mol% Eu3+ doped NaYF4 and KYF4 micro/nanocrystals have been synthesized. The materials were characterized by X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM) images, room temperature photoluminescence (PL) excitation and emission spectra, and luminescent dynamic decay curves. The XRD analysis suggested the crystalline structures of the obtained samples. The FE-SEM images indicated the morphology and size of the obtained samples. The PL spectra illustrate the optical properties of Eu3+ in the two samples. Since it is sensitive to the local environment of the ion, the Eu3+ presents different optical properties in the NaYF4 and KYF4 materials.

STRUCTURES AND MECHANICAL PROPERTIES OF MODULATED ZrB2/W AND ZrB2/WNx NANOMULTILAYERS

2010 ◽  
Vol 24 (01n02) ◽  
pp. 34-42 ◽  
Author(s):  
M. TAN ◽  
D. J. LI ◽  
G. Q. LIU ◽  
L. DONG ◽  
X. Y. DENG ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Significant Contribution ◽  
Layer Structure ◽  
Ion Beam ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Composition Modulation ◽  
Ion Beam Assisted Deposition ◽  
Xrd Patterns

ZrB 2, W , WN x coatings and ZrB 2/ W , ZrB 2/ WN x multilayered coatings have been synthesized by ion beam assisted deposition at room temperature. X-ray diffraction (XRD), XP-2 surface profiler, scanning electron microscopy (SEM) and nano indenter were employed to investigate the influence of modulation periods and N + beam bombardment on microstructure and mechanical properties of the coatings. The low-angle XRD patterns and cross-sectional SEM indicate a well-defined composition modulation and layer structure of the multilayers. The multilayers with modulation periods ranging from 9 to 16 nm without N + bombardment possessed higher hardness and elastic modulus than the rule-of-mixtures value of monolithic ZrB 2 and W coatings. The highest hardness was 24 GPa. N + bombardment to growing multilayers gave a significant contribution to mechanical property enhancement. When modulation period is 9.6 nm, ZrB 2/ WN x multilayer with 200 eV N + bombardment reveals the highest hardness (30.2 GPa) and elastic modulus. This hardest multilayer also showed the improved residual stress and fracture resistance.

scholarly journals Synthesis of novel red phosphate pigments from manganese carbonate to imitate natrophilite

Cerâmica ◽  
2018 ◽  
Vol 64 (372) ◽  
pp. 623-626
Author(s):  
H. Onoda ◽  
S. Fujikado
Keyword(s):  
Color Space ◽  
Xrd Analysis ◽  
Manganese Carbonate ◽  
X Ray Diffraction ◽  
Manganese Phosphate ◽  
A Value ◽  
Higher Temperature ◽  
Phosphate Pigments ◽  
Xrd Patterns ◽  
Visible Reflectance

Abstract A novel red pigment, sodium manganese phosphate (NaMnPO4), imitating natrophilite, was synthesized from manganese carbonate by heating under various conditions. The powders obtained were investigated by X-ray diffraction (XRD) analysis, infrared spectroscopy, ultraviolet-visible reflectance spectroscopy, and L*a*b* color space. Samples synthesized at 500-800 °C presented XRD patterns associated with NaMnPO4. By heating at a higher temperature, the samples exhibited lighter color. The sample synthesized at 700 °C indicated the highest a* value. Furthermore, the effects of varying relative amounts of constituents were also studied. The temperature and period of heating, volume of water, and phosphate content affected the color phase of the pigments.

Influence of Citric Acid on the Formation of Hydroxyapatite Powders by Using Ca(NO3)2-P2O5 Ethanol Solution System

2010 ◽  
Vol 152-153 ◽  
pp. 1248-1252
Author(s):  
Qing Chang ◽  
Hong Qiang Ru ◽  
Liang Yu ◽  
Ji Guang Li
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Transformation Process ◽  
Ethanol Solution ◽  
X Ray Diffraction ◽  
Solution System ◽  
Ca Addition ◽  
Xrd Patterns

In this study, nano-hydroxyapatite (HA) powders were synthesized via a simple sol-gel method using Ca(NO3)2•4H2O and P2O5 as starting materials. Two different precursors, with and without citric acid (CA), were prepared. The transformation process of HA from precursors, purity and particle size of the obtained HA powders were evaluated. HA derived from the precursor with CA showed a different transformation process from that without CA. It was observed that the content of CaO as an unavoidable major impurity was reduced due to the addition of CA. In the calcined powders from the CA-free precursor, X-ray diffraction (XRD) patterns revealed an intense CaO peak. For the calcined powders from the CA-addition precursor, XRD analysis showed a very weak CaO peak. It was also found that the synthesized HA powders from precursor with CA were finer than those without CA. The mechanism of the influence of CA on the formation, purity and particle size distribution of HA powders was discussed.

scholarly journals Synthesis of lead-based 1212 and 3212 superconductors by an aqueous sol-gel method

2009 ◽  
Vol 7 (3) ◽  
pp. 362-368 ◽  
Author(s):  
Giedre Nenartaviciene ◽  
Ramunas Skaudzius ◽  
Rimantas Raudonis ◽  
Aivaras Kareiva
Keyword(s):  
Sol Gel ◽  
Xrd Analysis ◽  
Structural Features ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Ceramic Samples ◽  
Xrd Patterns ◽  
Sol Gel Synthesis

AbstractThe aqueous sol-gel synthesis technique for the preparation of (Pb,Sr)Sr2(Y,Ca)Cu2O7±x (Pb-1212) and (Pb2,Cu)Sr2(Y,Ca)Cu2O8±x (Pb-3212) superconductors using two different complexing agents, namely 1,2-ethanediol and tartaric acid was studied. The phase transformations, composition and micro-structural features in the polycrystalline samples were studied by powder X-ray diffraction analysis (XRD), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD analysis of the ceramic samples obtained by calcination of Pb-Sr-Y-Ca-Cu-O acetate-glycolate precursor gels in air, for 10 hours at 800°C and at 825°C, showed the presence of homogeneous Pb-1212 and Pb-3212 crystallites as major phases. The XRD patterns of the ceramics obtained from Pb-Sr-Y-Ca-Cu-O acetate-tartrate precursor gels, however, showed multiphasic character. The critical temperature of superconductivity (TC (onset)) observed by resistivity measurements were found to be 91 K and 75 K for Pb-1212 and Pb-3212 samples, respectively.

Enhancing Electroconductivity of Yytria-Stabilised Zirconia Ceramic Using Graphene Platlets

2016 ◽  
Vol 690 ◽  
pp. 1-5 ◽  
Author(s):  
Kalaimani Markandan ◽  
Jit Kai Chin ◽  
Michelle T.T. Tan
Keyword(s):  
Ceramic Composite ◽  
Xrd Analysis ◽  
Zirconia Ceramic ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
Sintered Composite ◽  
A Value ◽  
Diffraction Peaks ◽  
Xrd Patterns

A simple method to produce graphene-Yytria stabilised zirconia (YSZ) ceramic composite with significant improvement in electrical properties is reported here. The material was consolidated by annealing in presence of Argon gas that allowed densification of the ceramics. A detailed x-ray diffraction (XRD) analysis was used to study the phases and crystallinity of graphene-YSZ ceramic composite. XRD patterns of the sintered composite showed that graphene diffraction peaks were detected at 2θ≈27°. Furthermore, experimental results indicate that electrical conductivity of YSZ composites drastically increased with the addition of graphene platelets, and it reached a value of 2.8 S/cm at 2 wt.%.

scholarly journals X-Ray Diffraction Techniques for Mineral Characterization: A Review for Engineers of the Fundamentals, Applications, and Research Directions

2021 ◽  
Author(s):  
Asif Ali ◽  
Yi Wai Chiang ◽  
Rafael M. Santos
Keyword(s):  
Analytical Techniques ◽  
Xrd Analysis ◽  
Future Research ◽  
Phase Identification ◽  
Learning Tools ◽  
X Ray Diffraction ◽  
Research Directions ◽  
X Ray ◽  
Mineral Characterization ◽  
Xrd Patterns

For many decades, X-ray diffraction (XRD) has been used for material characterization. With the recent development in material science understanding and technology, various new materials are being developed, which requires upgrading the existing analytical techniques such that intricate problems can be solved. Although, XRD is a well-established non-destructive technique, it still requires further improvements in its characterization capabilities, especially when dealing with complex mineral structures. The present review conducts comprehensive discussions on atomic crystal structure, XRD principle, its applications, uncertainty during XRD analysis, and required safety precautions, all in one place. It further discusses the future research directions, especially the use of artificial intelligence and machine learning tools for improving the effectiveness and accuracy of XRD technique for mineral characterization. It has been focused that how XRD patterns can be utilized for a thorough understanding of the crystalline structure, size, and orientation, dislocation density, phase identification, quantification, and transformation, information about lattice parameters, residual stress, and strain, and thermal expansion coefficient of materials. All these important discussions on XRD for mineral characterization are compiled in this short yet comprehensive review that would benefit specialists and engineers in the chemical, mining, iron, metallurgy, and steel industries.

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