Properties and structure of NiO-Al2O3 catalysts Communication 2. X-ray study of the effect of the proportions of components and the conditions of thermal treatment on phase composition and crystal structure

1958 ◽  
Vol 7 (8) ◽  
pp. 903-909
Author(s):  
A. M. Rubinshtein ◽  
V. M. Akimov ◽  
L. D. Kretalova
Keyword(s):  
Crystal Structure ◽  
Phase Composition ◽  
Thermal Treatment ◽  
X Ray

scholarly journals Люминофоры холодного голубого излучения на основе оксида алюминия, допированного диспрозием

2022 ◽  
Vol 64 (1) ◽  
pp. 95
Author(s):  
И.В. Бакланова ◽  
В.Н. Красильников ◽  
А.П. Тютюнник ◽  
Я.В. Бакланова
Keyword(s):  
Crystal Structure ◽  
Phase Composition ◽  
Diffraction Analysis ◽  
Powder Diffraction ◽  
Thermal Quenching ◽  
Emission Spectra ◽  
X Ray ◽  
White Emission ◽  
Uv Excitation ◽  
Quenching Of Luminescence

Al2О3:Dy3+ oxides with different colors luminescence were synthesized using precursor technology. The phase composition and crystal structure of the obtained materials were established by X-ray powder diffraction analysis. The excitation and emission spectra, decay curves, thermal quenching of luminescence were studied. Under UV excitation, the phosphors exhibit blue, purplish blue, white emission depending on the concentration of dysprosium and the temperature of annealing of the Al1-xDyx(OH)(HCOO)2 precursor in air.

Accuracy of XRPD QPA using the combined Rietveld–RIR method

2000 ◽  
Vol 33 (2) ◽  
pp. 267-278 ◽  
Author(s):  
Alessandro F. Gualtieri
Keyword(s):  
Crystal Structure ◽  
Phase Composition ◽  
Incoherent Scattering ◽  
Quantitative Phase Analysis ◽  
Polycrystalline Materials ◽  
Structure Model ◽  
Thermal Displacement ◽  
Model Assumption ◽  
Pyroclastic Rocks ◽  
X Ray

QPA (quantitative phase analysis) of polycrystalline materials using XRPD (X-ray powder diffraction) can be performed using the combined Rietveld and reference intensity ratio (RIR) methods, providing an estimate of both the crystalline and the amorphous phase in a mixture. Although the accuracy of estimates of the phase composition of simple ternary or quaternary mixtures is generally very good, uncertainties remain and bias the accuracy of phase determinations in complex systems such as pyroclastic rocks, which may contain two or more zeolite species, a number of other phases (generally up to four or five), and glass. The contribution of the incoherent scattering, biasing accuracy, in the glass determination has been discussed in an earlier work on the modal analysis of pyroclastic rocks [Gualtieri (1996).Powder Diffr.11, 97–106]. In this work, the assumption of the crystal structure, the influence of the spike addition, background and atomic (thermal) displacement parameters are discussed. It is shown that the structure-model assumption no longer holds for systems containing complex phases such as zeolites, as the accuracy is degraded and, as far as the influence of the added spike is concerned, there is an underestimation of the glass content with increasing amounts of added spike.

Phase and Crystal Structure Evolution of MoSi2-AlCr2 Quasibinary System Alloys

2012 ◽  
Vol 476-478 ◽  
pp. 734-738
Author(s):  
Qin Ma ◽  
Juan Hong Ren ◽  
Hui Chen
Keyword(s):  
Crystal Structure ◽  
Phase Composition ◽  
Mechanical Activation ◽  
Main Phase ◽  
Structure Evolution ◽  
X Ray ◽  
Quasibinary System

On the principle of alloying modification of the same crystal structure compound, MoSi2-AlCr2quasibinary system alloys were prepared by mechanical activation and hot pressed sintering.The phase composition and crystal structure evolution were investigated by X-ray diffractometer(XRD).The results showed that the main phase composition of alloys were MoSi2and Mo(Si,Al)2,the crystal structure was gradually transformed from tetragonal C11bMoSi2to hexagonal C40 Mo(Si,Al)2. (Mo,Cr)(Si,Al)2phase has not found in alloys.

Influence of thermal treatment and Au-loading on the growth of versatile crystal phase composition and photocatalytic activity of sodium titanate nanotubes

RSC Advances ◽  
2014 ◽  
Vol 4 (93) ◽  
pp. 51342-51348 ◽  
Author(s):  
Inderpreet Singh Grover ◽  
Satnam Singh ◽  
Bonamali Pal
Keyword(s):  
Crystal Structure ◽  
Photocatalytic Activity ◽  
Phase Composition ◽  
Thermal Treatment ◽  
Sodium Titanate ◽  
Titanate Nanotubes ◽  
Crystal Phase ◽  
Notable Change ◽  
Structure Morphology ◽  
Titanate Nanostructures

A coalescence influence of Au-loading followed by calcination at 800 °C led to a notable change in crystal-structure, morphology, phase composition and photocatalytic activity of titanate-nanostructures.

scholarly journals Phase composition of Bi2O3 specimens doped with Ti, Zr and Hf

2012 ◽  
Vol 77 (8) ◽  
pp. 1091-1096 ◽  
Author(s):  
Dejan Poleti ◽  
Ljiljana Karanovic ◽  
Miodrag Zdujic ◽  
Cedomir Jovalekic
Keyword(s):  
Crystal Structure ◽  
Phase Composition ◽  
Powder Diffraction ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Powder Mixtures ◽  
X Ray ◽  
Cell Parameters ◽  
Identical Crystal

Powder mixtures of ?-Bi2O3 containing 2, 5 and 10 mole % of TiO2, ZrO2 or HfO2 were homogenized, heated at 820?C for 24 h and quenched in air. X-ray powder diffraction technique was used to characterize the prepared samples. In all cases metastable Bi2O3 polymorphs, ?-Bi2O3 or ?-Bi2O3, are found as single or major phases. Addition of Ti4+ ions stabilizes ?-Bi2O3 polymorph, while either Zr4+ or Hf4+ ions stabilize ?-Bi2O3 polymorph. In the samples with 2 and 5 mole % of TiO2 the presence of even two ?-Bi2O3 phases (Bi12TiO20 compound and a very low Ti-doped ?-Bi2O3) was established. Similarly, in the sample with 2 mole % of HfO2 two ?-Bi2O3 phases were found. Phase composition of prepared samples, values of unit cell parameters and the appearance of two polymorphs with identical crystal structure but different unit cell parameters are discussed and compared with known data.

Studying the Physical Properties of Bi-2223 Nanostructure Prepared Thermal Treatment Method

2021 ◽  
Vol 1039 ◽  
pp. 269-273
Author(s):  
Zaid K. Alkaabi ◽  
Emad K. Al-Shakarchi
Keyword(s):  
Crystal Structure ◽  
Critical Temperature ◽  
Thermal Treatment ◽  
Electrical Resistance ◽  
Preparation Method ◽  
Treatment Method ◽  
Standard Document ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Difference

Recently, the researchers gave a great interest in the superconducting topic, as the preparation method is importance to reach a high critical temperature. In this study, the Bi2Sr2Ca2Cu3O10 (Bi-2223) compound prepared by thermal treatment method at different sintering temperatures such as (600, 700, 850) °C at (7) PH for (20 hrs). The phase formation was observed by X-ray diffraction, as well as information about the crystal structure, as the peaks were almost identical to the international standard document. the peaks are well indexed by tetragonal phase of Bi-2223. The results of the electrical resistance test showed that there is a difference in the critical temperature depending on the difference of the sintering temperatures The best result was at a temperature of 850 ° C. The sizes of the nanoparticles ranged from (22 - 123) nm, this is what the TEM measurements showed. It has been shown to be a successful method for preparing superconducting nanoparticles as (Bi-2223) compound

X-ray study of palladium catalysts. Influence of thermal treatment in hydrogen on the phase composition

1985 ◽  
Vol 28 (2) ◽  
pp. 373-377 ◽  
Author(s):  
D. V. Sokolskii ◽  
L. M. Kurashvili ◽  
K. Sergazieva ◽  
K. K. Kuzembaev
Keyword(s):  
Phase Composition ◽  
Thermal Treatment ◽  
Palladium Catalysts ◽  
X Ray

scholarly journals Synthesis and study of a novel 9P-type mixed layered tetradymite-like GeBi4Te4 compound in the Ge-Te-Bi system

2021 ◽  
Vol 22 (3) ◽  
pp. 401-406
Author(s):  
F.R. Aliyev
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Phase Composition ◽  
Lattice Parameter ◽  
The Novel ◽  
Layered Chalcogenides ◽  
X Ray ◽  
Parameter Values ◽  
Scanning Electron

Taking as a base structural properties of the tetradymite-like layered chalcogenide compounds, a novel ternary GeBi4Te4 phase was predicted and synthesized. The polycrystal of this compound was synthesized and its single-crystal was grown by the vertical Brigman-Stokbarger method. The phase composition of obtained samples was analyzed by differential thermal analysis (DTA), X-ray powder diffraction (XRD), and scanning electron microscope (SEM). It was determined that the novel phase melts peritectially at 538 °C and has the following lattice parameter values in a hexagonal configuration: a=4,4071(6)Å, c=17,384(2)Å (sp. gr P3m1). This crystal structure is considered a derivative of tetradymite-like layered chalcogenides and consists of alternating Bi bilayers and GeBi2Te4 septuple packets.

Features of crystal structure and phase composition of the anisotropic hexagonal ferrites bafe12o19 and bafe9,5al2,5o19, obtained by radiation-thermal sintering

2016 ◽  
Author(s):  
Пашков ◽  
A. Pashkov ◽  
Костишин ◽  
V. Kostishin ◽  
Исаев ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Beam ◽  
Phase Composition ◽  
Sintering Temperature ◽  
Barium Hexaferrite ◽  
Hexagonal Ferrites ◽  
X Ray ◽  
Fast Electron Beam ◽  
Thermal Sintering ◽  
Substituted Barium Hexaferrite

The method of radiation-thermal sintering (RTS) in the fast electron beam by accelerator ILU-6 obtained samples of barium hexaferrite BaFe12O19 and substituted barium hexaferrite BaFe9,5Al2,5O19 (with additions of Ni, Ti, Mn). The research synthesized samples was carried out by X-ray structural analysis and X-ray phase analysis. It is found that both compounds besides the main phase samples (BaFe12O19 and BaFe9,5Al2,5O19, respectively), is also present phase BaFe2O4. With increasing sintering temperature from 1100°C to 1300°C phase barium monoferrite intensity decreases or disappears completely, and at a temperature of 1400°C this phase is fixed again (its intensity continues to increase). The possibility of practical use of the results.

Preparing Fluorhydroxyapatite by Aqueous Precipitation Method

2011 ◽  
Vol 412 ◽  
pp. 167-170 ◽  
Author(s):  
Qing Xia Zhu ◽  
Wei Hui Jiang ◽  
Hong Da Wang ◽  
Chuan Shao
Keyword(s):  
Crystal Structure ◽  
Phase Composition ◽  
Ph Value ◽  
Synthesis Temperature ◽  
Ion Concentration ◽  
Precipitation Method ◽  
Fluoride Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Lattice Parameters

The nanosized fluorhydroxyapatite (FHA) had been synthesized by aqueous precipitation method. The effects of synthesis temperature,fluoride ion concentration and pH value on the fluoride substitution were investigated.The phase composition and the change of crystal structure were characterized by X-ray diffraction and fourier transform infrared spectroscopy. The results show that crystal lattice parameters and bond energy make changes by incorporation of F in the structure.The size of FHA crystals increase as the precipitation temperature. The phase composition of FHA is mainly controlled by the pH value.

Sign in / Sign up

Export Citation Format

Share Document