scholarly journals CRYSTALLIZATION AND CHARACTERIZATION OF CHROMIUM-CONTAINING SILICALITE-1

2010 ◽  
Vol 5 (3) ◽  
pp. 283-289 ◽  
Author(s):  
Hari Sutrisno ◽  
Endang Dwi Siswani ◽  
Susila Kristianingrum ◽  
Suharto Suharto
Keyword(s):  
Hydrothermal Method ◽  
Static Condition ◽  
Orthorhombic Structure ◽  
Space Group ◽  
Type Phase ◽  
Sio2 Phase ◽  
Pnma Space Group ◽  
Xrd Patterns

Chromium-containing silicalite-1, designed CrS-1, was synthesized by the hydrothermal method and characterized by XRD and FTIR techniques. The objectives of the research are to study the synthesis of CrS-1 and investigate the effect of crystallization temperatures and times toward its character. All samples of CrS-1 crystallized in orthorhombic structure and Pnma space group. The phase observed in the XRD patterns of CrS-1 synthesized from 150 to 190 oC for 11 days showed only MFI-type phase. The CrS-1 prepared under static condition for 1 day at 150 oC indicated -SiO2 phase, on the contrary, the samples conditioned for 2 to 8 days at 150 oC are only MFI phase.   Keywords: Crystallization, synthesis, chromium silicate CrS-1, incorporation.

scholarly journals Structural, optical, electric and dielectric characterization of a NaCu0.2Fe0.3Mn0.5O2 compound

RSC Advances ◽  
2022 ◽  
Vol 12 (3) ◽  
pp. 1563-1570
Author(s):  
Ichrak Ben Slima ◽  
Karim Karoui ◽  
Abdelfattah Mahmoud ◽  
Frédéric Boschini ◽  
Abdallah Ben Rhaiem
Keyword(s):  
Solid State ◽  
Solid State Method ◽  
Hexagonal System ◽  
Space Group ◽  
Dielectric Characterization ◽  
Type Phase ◽  
State Method

The compound NaCu0.2Fe0.3Mn0.5O2 was synthesized using a solid-state method and it crystallized in a hexagonal system with a R3̄m space group in an O3-type phase.

scholarly journals Modification of the Magnetic Properties of Co2Y Hexaferrites by Divalent and Trivalent Metal Substitutions

2015 ◽  
Vol 241 ◽  
pp. 93-125 ◽  
Author(s):  
Sami H. Mahmood ◽  
Muna D. Zaqsaw ◽  
Osama E. Mohsen ◽  
Ahmad Awadallah ◽  
Ibrahim Bsoul ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Exchange Interactions ◽  
High Coercivity ◽  
Xrd Pattern ◽  
A Value ◽  
Type Phase ◽  
Ball Milling Technique ◽  
Xrd Patterns

The present study is concerned with the fabrication and characterization of Me2Y substituted hexaferrites, Ba2Me2Fe12-xTxO22(Me = Co2+, Mg2+, and Cr2+, and T = Fe3+, and Ga3+). The samples were prepared by the conventional ball milling technique and sintering at 1200° C. The effect of the choices of Me and T ions on the structural and magnetic properties of the hexaferrites were investigated. XRD patterns, magnetic parameters, and Mössbauer spectra of the Co2Y were consistent with a single phase Y-type hexaferrite. However, the CoCr-Y sample was found to be dominated by the Y-type hexaferrite, and M-type and BaCrO4minority phases were observed in the XRD pattern of the sample. The small increase in saturation magnetization from about 34 emu/g up to 37.5 emu/g was therefore attributed to the development of the M-type phase. On the other hand, XRD pattern of the Cr2Y sample indicated the dominance of the M-type phase in this sample. The high coercivity (1445 Oe) of this sample is evidence of the transformation of the material from a typically soft magnetic material (Y-type) to a hard magnet (M-type). The Ga-substitution for Fe in Co2Y did not affect the saturation magnetization significantly, but the coercivity was reduced. However, the sample Ba2CoMgFe11GaO22exhibited a significant reduction of the saturation magnetization down to a value 26.6 emu/g, which could be due to the attenuation of the super-exchange interactions induced by the Mg2+substitution.

SYNTHESIS AND CHARACTERIZATION OF REBaBiO4 (WHERE RE = Pr and Gd) SYSTEM

2010 ◽  
Vol 24 (04) ◽  
pp. 413-421 ◽  
Author(s):  
A. MANIGANDAN ◽  
V. ANBARASU ◽  
S. SATHIYAKUMAR ◽  
L. K. KALIYAPERUMAL ◽  
K. JAYABALAN
Keyword(s):  
Solid State ◽  
Room Temperature ◽  
Single Phase ◽  
Energy Gap ◽  
Synthesis And Characterization ◽  
Orthorhombic Structure ◽  
Solid State Reaction Technique ◽  
Xrd Patterns ◽  
Structural Characterizations

The new bismuthates in the system REBaBiO 4 (where RE = Pr and Gd ) have been prepared by solid state reaction technique. From the structural characterizations through powder XRD patterns shows the single phase of the title compounds, which crystallizes in orthorhombic structure. The lattice parameters observed for the system BaPrBiO 4 is a = 6.512(3) Å, b = 6.589(5) Å, c = 8.732(4) Å and BaGdBiO 4 is a = 6.374(4) Å, b = 6.515(4) Å, c = 8.624(4) Å. The magnetization property of both the samples exhibit paramagnetic nature at both low and room temperature conditions. The energy gap value of the compound PrBaBiO 4 was calculated as 3.6046 eV, which shows the insulating nature of the material, and GdBaBiO 4 compound has got the range of 1.6356–2.1767 eV, which shows the semi-conducting nature at room temperature condition.

scholarly journals Synthesis and characterization of a solid solution series of the type Bi2MxMn4-xO10 (M = Cr3+, Co3+ and 0.0 ≤ x ≤ 2.0.)

2021 ◽  
Vol 45 (1) ◽  
pp. 13-26
Author(s):  
Aparna Sarker ◽  
AKM Lutfor Rahman ◽  
Tapas Debnath ◽  
Altaf Hussain
Keyword(s):  
Solid Solution ◽  
Single Phase ◽  
Synthesis Temperature ◽  
Nominal Composition ◽  
Solid Solution Series ◽  
Organic Precursor ◽  
Solution Series ◽  
Type Phase ◽  
Xrd Patterns

Bi2Mn4O10 was synthesized from corresponding metal salts in glycerin by using an organic precursor-based glycerin nitrate method. The precursor was heated at various temperatures (300 – 800 °C) for about 18 hours to determine the lowest synthesis temperature for the formation of Bi2Mn4O10. The XRD patterns of the calcined samples revealed that the desired mullite type phase started to form at 600 °C, which became more crystalline with further increase of calcination temperature. Attempts were also taken to prepare chromium and cobalt incorporated solid solution series with nominal composition Bi2MxMn4-xO10 (M = Cr3+ and Co3+) by the same procedure. The XRD data of these series exhibited mullite type single phase up to x = 0.7 and 0.1 compositions for chromium and cobalt, respectively. For further insertion of M, an extra phase appeared along with the mullite type phase. J. Bangladesh Acad. Sci. 45(1); 13-26: June 2021

Preparation and Characterization of Zn1-xNixFe2O4 Nanoparticles with Spinel Structure Synthesized by Hydrothermal Method

2018 ◽  
Vol 14 (6) ◽  
pp. 474-480 ◽  
Author(s):  
Xueliang Zhu ◽  
Zhiqiang Wei ◽  
Wenhua Zhao ◽  
Xu-dong Zhang ◽  
Xiao-juan Wu ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Spinel Structure

Correlative experimental and theoretical characterization of transition metal doped hydroxyapatite nanoparticles fabricated by hydrothermal method

2021 ◽  
Vol 173 ◽  
pp. 110911
Author(s):  
Anastasia V. Sadetskaya ◽  
Natalia P. Bobrysheva ◽  
Mikhail G. Osmolowsky ◽  
Olga M. Osmolovskaya ◽  
Mikhail A. Voznesenskiy
Keyword(s):  
Transition Metal ◽  
Hydrothermal Method ◽  
Hydroxyapatite Nanoparticles ◽  
Theoretical Characterization ◽  
Metal Doped

scholarly journals Multianvil High-Pressure/High-Temperature Synthesis and Characterization of multiferroic HP-Co3TeO6

2021 ◽  
Author(s):  
Gunter Heymann ◽  
Elisabeth Selb ◽  
Toni Buttlar ◽  
Oliver Janka ◽  
Martina Tribus ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Type Structure ◽  
Synthesis And Characterization ◽  
Temperature Synthesis ◽  
Space Group ◽  
Crystal System ◽  
High Temperature Synthesis ◽  
High Pressure High Temperature

By high-pressure/high-temperature multianvil synthesis a new high-pressure (HP) phase of Co3TeO6 was obtained. The compound crystallizes in the acentric trigonal crystal system of the Ni3TeO6-type structure with space group R3...

TEM Characterization of Pseudotetragonal Mullite

2001 ◽  
Vol 7 (S2) ◽  
pp. 426-427
Author(s):  
Bradley R. Johnson ◽  
Waltraud M. Kriven
Keyword(s):  
Phase Diagram ◽  
Spatial Relationship ◽  
Equilibrium Structure ◽  
Lattice Parameters ◽  
Orthorhombic Structure ◽  
Containerless Processing ◽  
Rich Phase ◽  
Tem Characterization ◽  
Solution Field

Mullite (3Al2O3•2SiO2) exists in a solid solution field (∼57-63 mol% Al2O3) as the only stable compound in the Al2O3•SiO2 phase diagram at ambient pressures. Equilibrium 3:2 mullite has an orthorhombic structure with b>a (o-mullite). However, when initially crystallized from molecularly mixed, 3:2 precursors at temperatures < 1200°C, the first phase that forms has lattice parameters with a ≈b. This structure is often termed pseudotetragonal mullite (pt-mullite), since even when the ‘a’ and ‘b’ lattice parameters are identical, they are symmetrically independent. Pseudotetragonal mullite has been shown to contain approx. 70 mol% Al2O3. with increasing time and temperature, the structure gradually assimilates the residual SiO2, and the lattice parameters change, such that by 1400°C, the material has attained its equilibrium structure and composition.TEM was used to determine the spatial relationship between the crystalline phase and the residual, amorphous, SiO2-rich phase in pt-mullite. The starting materials were quenched, 3:2 mullite beads and fibers (made by containerless processing).

Distorted chiolite crystal structures of α-Na5M3F14 (M=Cr,Fe,Ga) studied by X-ray powder diffraction

2003 ◽  
Vol 18 (2) ◽  
pp. 128-134 ◽  
Author(s):  
A. Le Bail ◽  
A.-M. Mercier
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Rietveld Refinements ◽  
Space Group ◽  
X Ray ◽  
Precise Characterization

The crystal structures of the chiolite-related room temperature phases α-Na5M3F14 (MIII=Cr,Fe,Ga) are determined. For all of them, the space group is P21/n, Z=2; a=10.5096(3) Å, b=7.2253(2) Å, c=7.2713(2) Å, β=90.6753(7)° (M=Cr); a=10.4342(7) Å, b=7.3418(6) Å, c=7.4023(6) Å, β=90.799(5)° (M=Fe), and a=10.4052(1) Å, b=7.2251(1) Å, c=7.2689(1), β=90.6640(4)° (M=Ga). Rietveld refinements produce final RF factors 0.036, 0.033, and 0.035, and RWP factors, 0.125, 0.116, and 0.096, for MIII=Cr, Fe, and Ga, respectively. The MF6 polyhedra in the defective isolated perovskite-like layers deviate very few from perfect octahedra. Subtle octahedra tiltings lead to the symmetry decrease from the P4/mnc space group adopted by the Na5Al3F14 chiolite aristotype to the P21/n space group adopted by the title series. Facile twinning precluded till now the precise characterization of these compounds.

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