scholarly journals Preparation, structure, surface and impedance analysis of Na2Zn0.5Mn0.5P2O7 ceramics

2017 ◽  
Vol 57 (3) ◽  
Author(s):  
Vilma Venckutė ◽  
Antonija Dindune ◽  
Dagnija Valdniece ◽  
Aija Krumina ◽  
Martynas Lelis ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Photoelectron Spectroscopy ◽  
Impedance Analysis ◽  
Solid State Reaction Method ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Temperature Range ◽  
Two Phases

The Na2Zn0.5Mn0.5P2O7 powder was prepared by the solid state reaction method. The powder structure was studied by X-ray diffraction (XRD) in the temperature range from room temperature (RT) to 520 K. The results of XRD measurements show that the obtained Na2Zn0.5Mn0.5P2O7 is a mixture of two phases: Na2MnP2O7, which crystallizes in the triclinic space group P1, and Na2ZnP2O7, which crystallizes in the tetragonal space group P42/mmm. The chemical compositions of the powder and ceramic samples were investigated by an energy dispersive X-ray spectrometer (EDX) and X-ray fluorescence spectroscopy (XFS). The surface of ceramics was examined by X-ray photoelectron spectroscopy (XPS). The electrical conductivity and dielectric permittivity of the ceramics were investigated from RT to 700 K in the frequency range 10–109 Hz. The relaxational dispersion of electrical conductivity in the investigated frequency and temperature range was found.

HIGH Tc SUPERCONDUCTIVITY AND SUBSTRUCTURE OF Bi-Sr-Ca-Cu-O SYSTEM

1988 ◽  
Vol 02 (02) ◽  
pp. 563-569 ◽  
Author(s):  
XING ZHU ◽  
SUNQI FENG ◽  
GUO LU ◽  
CHONGDE WEI ◽  
HANG ZHANG ◽  
...  
Keyword(s):  
Solid State Reaction Method ◽  
Main Phase ◽  
Nominal Composition ◽  
Chemical Compositions ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Lattice Constants ◽  
Two Phases

Bi x Sr 1 Ca 1 Cu y O z(x, y=1, 2 or 3) high Tc superconductors were synthesized by solid state reaction method. There are two superconducting phases in Bi-Sr-Ca-Cu-O system: 110 K phase and 80 K phase. The relative portion of the two phases and the state of superconducting connection are closely related to chemical compositions and the conditions of processing. X-ray powder diffraction shows that there exists a main phase with orthorhombic symmetry in the samples of different compositions and conditions of processing. According to X-ray diffraction data, the lattice constants of the main phase in the sample of nominal composition Bi 1 Sr 1 Ca 1 Cu 2 O z have been determined as aο=5.44Å, bο=5.35Å and co=30.66Å. Electron diffraction shows complicated modulation structure along b− and c− axes. High resolution image along [001] zone axis indicates the modulation structure along b− axis.

A conformational polymorphic transition in the high-temperature ∊-form of chlorpropamide on cooling: a new ∊′-form

2009 ◽  
Vol 65 (6) ◽  
pp. 770-781 ◽  
Author(s):  
Tatiana N. Drebushchak ◽  
Yury A. Chesalov ◽  
Elena V. Boldyreva
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Structural Changes ◽  
Molecular Conformation ◽  
Polymorphic Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Temperature Range ◽  
Two Phases

Structural changes in the high-temperature ∊-polymorph of chlorpropamide, 4-chloro-N-(propylaminocarbonyl)benzenesulfonamide, C10H13ClN2O3S, on cooling down to 100 K and on reverse heating were followed by single-crystal X-ray diffraction. At temperatures below 200 K the phase transition into a new polymorph (termed the ∊′-form) has been observed for the first time. The polymorphic transition preserves the space group Pna21, is reversible and is accompanied by discontinuous changes in the cell volume and parameters, resulting from changes in molecular conformation. As shown by IR spectroscopy and X-ray powder diffraction, the phase transition in a powder sample is inhomogeneous throughout the bulk, and the two phases co-exist in a wide temperature range. The cell parameters and the molecular conformation in the new polymorph are close to those in the previously known α-polymorph, but the packing of the z-shaped molecular ribbons linked by hydrogen bonds inherits that of the ∊-form and is different from the packing in the α-polymorph. A structural study of the α-polymorph in the same temperature range has revealed no phase transitions.

Two-Phase Structure of Fluorinated Powdered Silica Resulting from Deep Processing of Rice Wastes

2018 ◽  
Vol 7 (1) ◽  
pp. 38-44 ◽  
Author(s):  
А. Рашковский ◽  
A. Rashkovskiy ◽  
Е. Политова ◽  
E. Politova ◽  
А. Меркушкин ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Physicochemical Analysis ◽  
Nano Particles ◽  
Deep Processing ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Inductively Coupled ◽  
Two Phases

In this investigation the structure of «green» silica maid with rice husk has been studied by methods of physicochemical analysis. By method of X-ray diffraction it has been found that the samples of «green» silica powders are completely amorphous, and the observed amorphous halo consists of two components. By method of scanning electron microscopy it has been revealed that nano-particles of «green» SiO2 can form agglomerates and microstructures with dimensions from 0,1 to 500 microns, containing numerous pores, which presence has been confirmed by sorption measurements. By method of mass spectrometry with inductively coupled plasma has been found the presence of aluminum, titanium and nickel mechanical impurities in the «green» SiO2 powders. By method of X-ray photoelectron spectroscopy significant amount of fluorine atoms in «green» silica (up to 5% (at.)) has been revealed, which could be introduced in SiO2 in the process of its preparation. In such a case, it was found that fluorine interacts with «green» silica by means of two mechanisms, leading to appearance of two phases within fluorinated powders of «green» SiO2.

Investigation on the Preparation Processes of Cu-Bi Master Alloy

2011 ◽  
Vol 335-336 ◽  
pp. 841-844 ◽  
Author(s):  
Li Na Zhang ◽  
Bai Xiong Liu
Keyword(s):  
Electron Microscopy ◽  
Melting Temperature ◽  
Master Alloy ◽  
Holding Time ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Two Phases ◽  
Fluorescence Analyzer ◽  
Scanning Electron

The Microstructure of Cu-Bi master alloy with different melt processes, such as different melting temperature and holding time, was observed by PHILIPS-XL30 scanning electron microscopy (SEM); phase analysis was conducted by Miniflex X-ray diffraction(XRD); Magix(PW2424) X-ray fluorescence analyzer(XRF) was used to analyze chemical compositions of Cu-Bi master alloy. The results show that there are Cu and Bi two phases in the Cu-Bi master alloy; The yielding rate of bismuth decreases with the rising melting temperature. It decreases slowly between 1100 °C to 1150 °C,while it decreases rapidly between 1150 °C to 1200 °C.The bismuth particles in the Cu-Bi master alloy prepared at 1100 °C are much larger than those prepared at 1150 °C,while the size of bismuth particles change little from 1150 °C to 1200 °C. So the better melting temperature of preparing Cu-Bi master alloy is 1150 °C.The yielding rate of bismuth decreases with the holding time increasing. But when the holding time is too short, there are large bismuth particles in Cu-Bi alloy .So the better holding time is 120s.

Crystal structure and thermal expansion of hexakis(phenylthio)benzene and its CBr4 clathrate

1995 ◽  
Vol 73 (4) ◽  
pp. 513-521 ◽  
Author(s):  
Darek Michalski ◽  
Mary Anne White ◽  
Pradip K. Bakshi ◽  
T. Stanley Cameron ◽  
Ian Swainson
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Neutron Powder Diffraction ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

The crystal structures of hexakis(phenylthio)benzene (HPTB) and its CBr4 clathrate have been determined by single crystal X-ray diffraction data collected at T = 18 °C and refined to final Rw of 0.036 and 0.047, respectively. Pure HPTB is triclinic, space group [Formula: see text] (No. 2), with a = 9.589(2) Å, b = 10.256(1) Å, c = 10.645(2) Å, α = 68.42(1)°, β = 76.92(2)°, γ = 65.52(1)°, and Z = 1. The CBr4 clathrate of HPTB is rhombohedral, space group [Formula: see text] (No. 148), with a = 14.327(4) Å, b = 20.666(8) Å, and Z = 3. The host–guest mole ratio of HPTB–CBr4 is 1:2. Neutron powder diffraction was carried out on powders of both compounds in the temperature range 25 K < T < 295 K. Thermal expansion coefficients were determined for HPTB and HPTB–CBr4 over this temperature range. Keywords: thermal expansion, crystal structure, clathrate.

Effect of Sintering on Structural Modification and Phase Transition of Al-Substituted LLZO Electrolytes for Solid State Battery Applications

2021 ◽  
Vol 18 (3) ◽  
Author(s):  
K. Ganesh Kumar ◽  
P. Balaji Bhargav ◽  
C. Balaji ◽  
Ahmed Nafis ◽  
K. Aravinth ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Solid Electrolyte ◽  
Photoelectron Spectroscopy ◽  
Lithium Ion ◽  
Impedance Analysis ◽  
Chemical Compositions ◽  
X Ray ◽  
Reitveld Refinement ◽  
Solid State Battery

Abstract Owing to high lithium ion conductivity and good stability with lithium metal, Li7La3Zr2O12 (LLZO—a solid electrolyte) has emerged as a viable candidate for solid-state battery applications. In the current study, Al-substituted LLZO (Al-LLZO) powder is synthesized using a typical solid-state reaction. The pellets are made with the synthesized powder and are subjected to annealing for different durations and its effect on the structural properties of the Al-LLZO is investigated in detail. Reitveld refinement of the powder X-ray diffraction pattern reveals that the sintered Al-LLZO belong to the cubic system with the Ia-3d space group at room temperature. Morphology and microstructural properties of sintered powder are analyzed using field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM)/selected area electron diffraction (SAED), respectively. The FESEM image of LLZO pellets shows well-structured cubic grains spread evenly over on the surface after sintering. The chemical compositions of the sample are identified using energy dispersive X-ray analysis (EDAX). The surface chemistry of the prepared samples is examined by X-ray photoelectron spectroscopy (XPS), which states that the observed photoelectron signals from O 1s at about 531 eV and Li1s at 54.52 eV correspond to the Li-O bond in Al-LLZO. Raman spectra have been analyzed and the observed Raman peaks appearing at 299 cm−1, 393 cm−1, 492 cm−1, and 514 cm−1 were assigned to Eg, F2g, A1g, and F2g, respectively. Phase transformation from C-LLZO to the pyrochore LZO phase is noticed when the sample is sintered for 12 h at 1100 °C. The impedance analysis is carried out to measure the conductivity of the Al-LLZO pellet and is found to be 0.3 × 10−5 S cm−1, which is suitable for solid electrolyte applications in lithium ion batteries.

STUDY ON ABNORMAL PHENOMENON ABOUT ENHANCED ELECTRICAL CONDUCTIVITY OF Bi1-xBaxFeO3 CERAMICS

2014 ◽  
Vol 28 (05) ◽  
pp. 1450009 ◽  
Author(s):  
H. J. WANG ◽  
S. Y. WANG ◽  
W. F. LIU ◽  
X. J. XI ◽  
FENG GUO ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Solid Phase ◽  
Electrical Conductance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multiferroic Properties ◽  
Abnormal Phenomenon ◽  
Sintering Method

In order to investigate the effects of Ba doping BiFeO 3 on multiferroic properties, Bi 1-x Ba x FeO 3(0≤x≤1)( Ba x BFO ) ceramics were fabricated via rapid solid phase sintering method, and material's structures and electrical properties were investigated. The phase transitions from rhombohedral to pseudo-cubic (x = 10%) and then to tetragonal (x = 40%) were confirmed by X-ray diffraction investigation. Although the electrical conductivity of Ba x BFO (x = 10%, 20% and 30%) ceramics was low, which is a similar trend to previous reports, an abnormal enhancement of electrical conductance was observed in Ba x BFO (x = 1%, 3% and 5%) ceramics. Such as, the electrical conductivity of Ba 0.03 BFO is calculated to be ~106 Ω⋅ cm that is five orders of magnitude higher than that of the BiFeO 3. This has been discussed and ascribed to more percent of oxygen vacancies and Fe 2+ ions in Ba x BFO ceramics, as confirmed by X-ray photoelectron spectroscopy investigation.

Synthesis and Luminescence Properties of Doped Magnesium Boro-Tellurite Ceramics

2015 ◽  
Vol 73 (1) ◽  
Author(s):  
Nur Zu Ira Bohari ◽  
R. Hussin ◽  
Zuhairi Ibrahim ◽  
Hendrik O. Lintang
Keyword(s):  
Rare Earth ◽  
Solid State ◽  
Solid State Reaction Method ◽  
Luminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Emission Transition ◽  
Bending Mode ◽  
Two Phases ◽  
Rare Earth Doped

Glass has been widely utilized in the field of lighting, telecommunication and spectroscopy. Boro-tellurite is one of the suitable glasses used for solid state lighting and laser application. The investigation on the luminescence properties of rare earth doped ceramic is rarely used due to the opacity. In this paper boro-tellurite prepared in ceramic can show the better luminescence with the less advantage. The aim of this paper is to present the effect and advantages in luminescence results of boro-tellurite ceramics doped with the constant amount of rare earth. Doped magnesium boro-tellurite with Eu3+ and Dy3+ ceramic have been prepared using solid state reaction method with the compositions of xTeO2-(70-x)B2O3-30MgO with 10≤x≤40, and have been doped with Eu2O3 (1mol%) and Dy2O3 (1mol%) . The characterizations of the samples have been investigated by means of X-Ray diffraction, Raman, Infrared and Photoluminescence spectroscopy. From the X-ray diffraction results, two phases are assigned to MgTe2O5 and Mg2B2O5. Raman spectroscopy showed strong bands observed in the vicinity of 140, 175, 220, 266, 332, 403, 436, 646, 694, 723, 757 and 806 cm-1. FTIR spectra showed bands located in the range between 400-800 cm-1 are assigned to the bending mode of Te-O-Te, TeO3 and TeO4. In the range of 800-1400 cm-1,the bands are associated with B-O, B-O-B, BO3 and BO4 bonds. The emission transition 5D0-7F2 corresponded to the red emission (612 nm) was found to be the most intense in all the Eu3+-doped magnesium boro-tellurite ceramics.  

scholarly journals Study of dielectric behavior and electrical properties of hematite α-Fe2O3 doped with Zn

2012 ◽  
Vol 44 (3) ◽  
pp. 307-321 ◽  
Author(s):  
M.V. Nikolic ◽  
M.P. Slankamenac ◽  
N. Nikolic ◽  
D.L. Sekulic ◽  
O.S. Aleksic ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Spinel Phase ◽  
Dielectric Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
Zn Content ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Two Phases

The effects of Zn-doping on the dielectric behavior and electrical properties of bulk ?-Fe2O3 have been studied. X-ray diffraction analysis revealed the presence of two phases in all samples: hematite and spinel ZnFe2O4, with the amount of spinel phase increasing with increasing Zn content. Scanning electron microscopy analysis combined with energy dispersive X-ray spectroscopy showed that the Zn-bearing phase occurred in the form of individual spinel ZnFe2O4 grains in a hematite matrix. DC conductivity was measured in the temperature range 25-225oC (298-498 K). Impedance spectroscopy measurements in the same temperature range were carried out in the frequency range 100Hz to 10 MHz. Increase in the Zn content resulted in increased electrical conductivity and higher values of the dielectric constant. The resistance and capacitance of grains and grain boundaries were analyzed by modeling the experimental results using an equivalent circuit.

scholarly journals Zirconium tetrachloride revisited

2018 ◽  
Vol 74 (3) ◽  
pp. 307-311
Author(s):  
Rosendo Borjas Nevarez ◽  
Samundeeswari Mariappan Balasekaran ◽  
Eunja Kim ◽  
Philippe Weck ◽  
Frederic Poineau
Keyword(s):  
Phase Transformation ◽  
Single Crystal ◽  
Structural Parameters ◽  
X Ray Diffraction ◽  
Zirconium Tetrachloride ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Temperature Range ◽  
Crystallographic Study

Zirconium tetrachloride, ZrCl4, is a strategic material with wide-ranging applications. Until now, only one crystallographic study on ZrCl4has been reported [Krebs (1970).Z. Anorg. Allg. Chem.378, 263–272] and that was more than 40 years ago. The compound used for the previous determination was prepared from ZrO2and Cl2–CCl4, and single-crystal X-ray diffraction (SCXRD) studies on ZrCl4obtained from Zr metal have not yet been reported. In this context, we prepared ZrCl4from the reaction of Zr metal and Cl2gas in a sealed tube and investigated its structure at 100, 150, 200, 250, and 300 K. At 300 K, the SCXRD analysis indicates that ZrCl4crystallizes in the orthorhombic space groupPca21[a= 6.262 (9),b= 7.402 (11),c= 12.039 (17) Å, andV= 558.0 (14) Å3] and consists of infinite zigzag chains of edge-sharing ZrCl6octahedra. This chain motif is similar to that observed previously in ZrCl4, but the structural parameters and space group differ. In the temperature range 100–300 K, no phase transformation was identified, while elongation of intra-chain Zr...Zr [3.950 (1) Å at 100 K and 3.968 (5) Å at 300 K] and inter-chain Cl...Cl [3.630 (3) Å at 100 K and 3.687 (9) Å at 300 K] distances occurred.

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