On the Formation of Nanograined LiCo2O3(OH) Spinel-Type Material Synthesized via Modified Low-Temperature Sol-Gel Approach

2015 ◽  
Vol 1119 ◽  
pp. 106-110
Author(s):  
Rinlee Butch M. Cervera ◽  
Shu Yamaguchi
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Spinel Structure ◽  
Sol Gel ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Spinel Type ◽  
Selected Area Electron Diffraction ◽  
High Temperature Xrd ◽  
Average Grain Size

A new lithium cobalt oxyhydroxide compound has been successfully synthesized. This new compound has been found to be related to the low temperature LiCoO2 (LT-LiCoO2) spinel structure formed at low processing temperatures. With the use of a modified sol-gel approach, this compound with the composition of LiCo2O3(OH) can be successfully synthesized at around 150 °C. Structural analyses using powder X-ray diffraction (XRD) and selected area electron diffraction (SAED) suggest a cubic-spinel structure, which is also supported by FT-IR and TG/DTA analyses. In addition, from the TEM morphological analysis, a very fine nanograined LiCo2O3(OH) powder with an average grain size of 5 nm has been obtained. From these results, the presence of OH or water at low processing temperatures promotes a favorable formation of this structure. At higher temperatures (>400 °C), the phase transforms to a layered high-temperature LiCoO2 (HT-LiCoO2) structure with the excess cobalt precipitated as Co3O4 as suggested by the in-situ high temperature XRD analysis.

scholarly journals Effect of Re and Tm-site on morphology structure and optical band gap of ReTmO3 (Re: La, Ce, Nd, Gd, Dy, Y and Tm: Fe, Cr) prepared by sol-gel method

2018 ◽  
Vol 64 (4) ◽  
pp. 381
Author(s):  
Muhammad Tufiq Jamil ◽  
Javed Ahmad ◽  
Syed Hamad Bukhari ◽  
Murtaza Saleem
Keyword(s):  
Band Gap ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
X Ray ◽  
Average Grain Size ◽  
Auto Combustion ◽  
Uv Visible

Rare earth nano sized pollycrystalline orthoferrites and orthocromites ReT mO3 (Re = La, Nd, Gd, Dy, Y and T m = Fe, Cr) have been synthesized by sol-gel auto combustion citrate method. The samples have been characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and UV-visible spectroscopy. The samples are single phase as confirmed by XRD analysis and correspond to the orthorhombic crystal symmetry with space group pbnm. Debye Scherer formula and Williamson Hall analysis have been used to calculate the average grain size which is consistent with that of determined from SEM analysis and varied between 25-75 nm. The elemental compositions of all samples have been checked by EDX analysis. Different crystallographic parameters are calculated with strong structural correlation among Re and Tm sites. The optical energy band gap has been calculated by using Tauc relation estimated to be in the range of 1.77 - 1.87 eV and 2.77 - 3.14 eV, for ReFeO3 and ReCrO3, respectively.

scholarly journals Synthesis of Ca-Psz nanoparticles using sol-gel technique with chitosan as a dispersant for raw materials restoration and dental rehabilitation equipment

2013 ◽  
Vol 25 (3) ◽  
Author(s):  
Fadilla Rizky Prameshwari ◽  
Elin Karlina ◽  
Zulia Hasratiningsih
Keyword(s):  
Low Temperature ◽  
Raw Materials ◽  
Sol Gel ◽  
Dental Materials ◽  
Xrd Analysis ◽  
Transformation Toughening ◽  
X Ray Diffraction ◽  
Dental Rehabilitation ◽  
Gel Technique ◽  
Two Stages

Introduction: Zirconia (ZrO2) is a metal-free substance that rapidly improving as dental materials that has a good properties which are high biocompatibility, esthetics, and strength. Addition of a stabilizer like CaO will increase the mechanical properties of zirconia due to the transformation toughening. Methods: The Calcia Partially Stabilized Zirconia (Ca-PSZ) nanoparticles can be synthesized by using sol gel technique. This method makes easier to control the purity, homogeneity and physical characteristics at low temperature. This method consists of two stages, hydrolysis and condensation. The precursor were used  Zirconium Chloride (ZrCl4) with 0,1 M concentration and Calcia as stabilizer with 7% concentration. The addition of Calcia will help the tetragonal crystals forming at low temperature. Calcination temperature was used 900o C. To prevent conglomeration or agglomeration, dispersants are needed. One of the dispersants available is chitosan. Results: X-Ray Diffraction (XRD) analysis identifies that there are tetragonal and monoclinic phase with a percentage of 85% and 15% perspectively for sample without using chitosan and 100% tetragonal for sample that using chitosan. Analysis of Scanning Electron Microscope (SEM) results that particles with chitosan are more homogenous and dispersed with smaller size produced compared to particles without chitosan. Conclusion: From the results of the analysis, Ca-PSZ with sol-gel technique can produce nanoparticle and addition of  chitosan  can dispersed nanoparticles that could be used as material restoration and rehabilitation component  in dentistry.

High-Temperature XRD Analysis of Polymers

1990 ◽  
Vol 34 ◽  
pp. 459-463
Author(s):  
Robert W. Green
Keyword(s):  
High Temperature ◽  
Temperature Control ◽  
Polymeric Materials ◽  
Xrd Analysis ◽  
Sample Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature Xrd ◽  
Insight Into

High-temperature x-ray diffraction has many applications. Applied to polymeric materials it is a useful tool for investigating changes in crystallinity, providing insight into molding and extrusion problems, and for examining solvent-resistancy problems. An example of the increasing crystailine character of a polymer as a function of temperature can be seen in figure 1. Diffraction scans at 25°C, 100°C, 150°C, and 200°C clearly show the increasing crystalline character of the potymer with an increase in temperature. Control of sample temperature for a polymer is very important, when analyzing under air, because a momentary overshoot in temperature may lead to the sample igniting. High-temperature investigations of polymers are also subject to the problem of the sample warping and bowing.

PHOTOCATALYTIC PROPERTIES OF NANOCRYSTALLINE ZnFe2O4 SYNTHESIZED AT LOW TEMPERATURE BY SOLVO-COMBUSTION METHOD

2011 ◽  
Vol 10 (06) ◽  
pp. 1231-1235 ◽  
Author(s):  
S. B. KONDAWAR ◽  
S. R. THAKARE ◽  
N. S. BHAVE ◽  
D. K. BURGHATE
Keyword(s):  
Low Temperature ◽  
Visible Light ◽  
Spinel Structure ◽  
Single Phase ◽  
Combustion Method ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Visible ◽  
Reference Catalyst

Facile, low temperature solvo-combustion synthesis route is used to prepare nanocrystalline ZnFe2O4 having spinel structure. Synthesized ZnFe2O4 has been analyzed using X-ray diffraction (XRD), TEM and UV-Visible spectrometry. XRD analysis indicates the single-phase of the material ZnFe2O4 , whose crystallite size was found to be 10 nm evaluated using Scherrer's equation and confirmed from TEM image. The visible-light-activated photocatalytic activity of the nanocrystalline ZnFe2O4 has been compared to P-25 degussa TiO2 reference catalyst, using a visible light for the degradation of phenol.

The Application of X-Ray Diffraction at Elevated Temperatures to Study the Mechanism of Formation of Sodium Tripolyphosphate

1961 ◽  
Vol 5 ◽  
pp. 276-284
Author(s):  
E. L. Moore ◽  
J. S. Metcalf
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Amorphous Phase ◽  
Elevated Temperatures ◽  
Sodium Tripolyphosphate ◽  
X Ray Diffraction ◽  
Mechanism Of Formation ◽  
X Ray ◽  
Temperature Form ◽  
High Temperature Form

AbstractHigh-temperature X-ray diffraction techniques were employed to study the condensation reactions which occur when sodium orthophosphates are heated to 380°C. Crystalline Na4P2O7 and an amorphous phase were formed first from an equimolar mixture of Na2HPO4·NaH2PO4 and Na2HPO4 at temperatures above 150°C. Further heating resulted in the formation of Na5P3O10-I (high-temperature form) at the expense of the crystalline Na4P4O7 and amorphous phase. Crystalline Na5P3O10-II (low-temperature form) appears after Na5P3O10-I.Conditions which affect the yield of crystalline Na4P2O7 and amorphous phase as intermediates and their effect on the yield of Na5P3O10 are also presented.

scholarly journals X-ray diffraction analysis of kaolin M1 and M2 via the Williamson–Hall and Warren–Averbach methods

2021 ◽  
pp. 174751982098472
Author(s):  
Lalmi Khier ◽  
Lakel Abdelghani ◽  
Belahssen Okba ◽  
Djamel Maouche ◽  
Lakel Said
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Low Temperature ◽  
Diffraction Analysis ◽  
Mechanical Resistance ◽  
X Ray Diffraction ◽  
Integral Breadth ◽  
X Ray ◽  
Mullite Phase

Kaolin M1 and M2 studied by X-ray diffraction focus on the mullite phase, which is the main phase present in both products. The Williamson–Hall and Warren–Averbach methods for determining the crystallite size and microstrains of integral breadth β are calculated by the FullProf program. The integral breadth ( β) is a mixture resulting from the microstrains and size effect, so this should be taken into account during the calculation. The Williamson–Hall chart determines whether the sample is affected by grain size or microstrain. It appears very clearly that the principal phase of the various sintered kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted at low temperature (1200 °C) during 1 h and also the case of the mixtures of the type chamotte cooks with 1350 °C during very long times (several weeks). This result is very significant as it gives an element of explanation to a very significant quality of mullite: its mechanical resistance during uses at high temperature remains.

Structural, Magnetic and Dielectric Analysis of Higher Magnetic Mn Doped Zn-Cr Oxide Nanoparticles

2021 ◽  
Vol 9 (VI) ◽  
pp. 95-102
Author(s):  
S. D. Balsure
Keyword(s):  
Type Strain ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Xrd Analysis ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Microstructural Parameters ◽  
Auto Combustion ◽  
Mn Doped ◽  
Combustion Technique

Higher magnetic Mn doped Zn-Cr oxide nanoparticles with general compositional formula MxZn0.95-xCr0.05O have been synthesized by using sol-gel auto combustion technique. Room temperature X-ray diffraction (XRD) technique has been employed to study the structural and microstructural parameters of the as-prepared samples. XRD analysis confirms the phase purity and hexagonal wurtzite structure of all the samples. Replacement of Zn2+ ions by Mn2+ ions shifts peak positions slightly towards the lower angles which in turn expands the lattice lengths ‘a’ from 3.2487 to 3.2528 Å and ‘c’ from 5.2043 to 5.2118 Å. Crystallite size obtained from Scherrer equation was confirmed by Williamson – Hall (W-H) and size – strain plot methods (SSP). Both W-H and SSP methods reveals the tensile type strain for undoped sample and comprehensive type strain for Mn2+ doped samples. Magnetic properties were investigated by using vibrating sample magnetometer. Diluted ferromagnetic behaviour is observed for all the samples and saturation magnetization (MS) increases from 0.0514 to 0.1163 emu/gm. Two-probe technique was employed to understand the dielectric behaviour of the samples as a function of frequency. At lower frequency region, both dielectric constant () and dielectric loss tangent (tan ) shows higher values and decreases with the increasing applied frequency.

scholarly journals The Influence of Annealing Temperature on the Structure and Magnetic Properties of Nanocrystalline BiFeO3 Prepared by Sol–Gel Method

2021 ◽  
Author(s):  
T. Pikula ◽  
T. Szumiata ◽  
K. Siedliska ◽  
V. I. Mitsiuk ◽  
R. Panek ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Weak Ferromagnetism ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Average Grain Size ◽  
Spin Cycloid

AbstractIn this work, BiFeO3 powders were synthesized by a sol–gel method. The influence of annealing temperature on the structure and magnetic properties of the samples has been discussed. X-ray diffraction studies showed that the purest phase was formed in the temperature range of 400 °C to 550 °C and the samples annealed at a temperature below 550 °C were of nanocrystalline character. Mössbauer spectroscopy and magnetization measurements were used as complementary methods to investigate the magnetic state of the samples. In particular, the appearance of weak ferromagnetic properties, significant growth of magnetization, and spin-glass-like behavior were observed along with the drop of average grain size. Mössbauer spectra were fitted by the model assuming cycloidal modulation of spins arrangement and properties of the spin cycloid were determined and analyzed. Most importantly, it was proved that the spin cycloid does not disappear even in the case of the samples with a particle size well below the cycloid modulation period λ = 62 nm. Furthermore, the cycloid becomes more anharmonic as the grain size decreases. The possible origination of weak ferromagnetism of the nanocrystalline samples has also been discussed.

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