Nanoscale Structural Features of Ultra-fine Zirconia Powders Obtained Via Precipitation-hydrothermal Treatment Route

2005 ◽  
Vol 878 ◽  
Author(s):  
Vladislav A. Sadykov ◽  
Vladimir I. Zaikovskii ◽  
Dmitrii A. Zyuzin ◽  
Ella M. Moroz ◽  
Elena B. Burgina ◽  
...  
Keyword(s):  
Hydrothermal Treatment ◽  
Single Phase ◽  
Fine Particles ◽  
Structural Features ◽  
Extended Defects ◽  
X Ray Diffraction ◽  
Xrd Patterns ◽  
Symmetric Structures ◽  
Zirconia Powders ◽  
Hydrated Zirconia

AbstractGenesis of the structure of zirconia fine particles prepared by precipitation of amorphous hydrated zirconia by ammonia from the ZrO(NO3)2 solution followed by a mild hydrothermal treatment (HTT) of precipitate, washing and calcination under air up to 1000 °C has been studied by HRTEM, X-ray diffraction, Raman and FTIRS. HTT rearranges the structure of amorphous zirconia, which helps to obtain nearly single-phase monoclinic nanozirconia (particle size 5-15 nm) after a mild calcination at 500 °C. Dehydroxilation and sintering of these nanoparticles at higher (600-650 °C) temperatures generate polysynthetic (001) twins. Modeling revealed that reappearance of the (111) “cubic” reflex in XRD patterns of samples calcined at 600-650 °C can be due to these extended defects. In their vicinity, the seven-fold Zr-O coordination sphere is retained, while packing of ZrO7 polyhedra is varied towards more symmetric structures, thus causing disappearance of the Raman spectra.

Structural and Magnetic Hysteresis Properties of Co-Zr Substituted Hexagonal Barium Ferrites

2015 ◽  
Vol 7 (1) ◽  
pp. 1346-1351
Author(s):  
Ch.Gopal Reddy ◽  
Ch. Venkateshwarlu ◽  
P. Vijaya Bhasker Reddy
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Magnetic Hysteresis ◽  
Grain Morphology ◽  
Hexagonal Structure ◽  
Ion Composition ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
Barium Ferrites ◽  
Xrd Patterns

Co-Zr substituted M-type hexagonal barium ferrites, with chemical formula BaCoxZrxFe12-2xO19 (where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), have been synthesized by double sintering ceramic method. The crystallographic properties, grain morphology and magnetic properties of these ferrites have been investigated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM). The XRD patterns confirm the single phase with hexagonal structure of prepared ferrites. The magnetic properties have been investigated as a function of Co and Zr ion composition at an applied field in the range of 20 KOe. These studies indicate that the saturation magnetization (Ms) in the samples increases initially up to the Co-Zr composition of x=0.6 and decreases thereafter. On the other hand, the coercivity (Hc) and Remanent magnetization (Mr) are found to decrease continuously with increasing Co-Zr content. This property is most useful in permanent magnetic recording. The observed results are explained on the basis of site occupation of Co and Zr ions in the samples.

scholarly journals Influence of Li2CO3 addition on electrical and magnetic properties of Ni0.6Mg0.4Fe2O4

2020 ◽  
Vol 10 (03) ◽  
pp. 2050003
Author(s):  
M. R. Hassan ◽  
M. T. Islam ◽  
M. N. I. Khan
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Low Frequency ◽  
Solid State Reaction Method ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Frequency Regime ◽  
Xrd Patterns

In this research, influence of adding Li2CO3 (at 0%, 2%, 4%, 6%) on electrical and magnetic properties of [Formula: see text][Formula: see text]Fe2O4 (with 60% Ni and 40% Mg) ferrite has been studied. The samples are prepared by solid state reaction method and sintered at 1300∘C for 6[Formula: see text]h. X-ray diffraction (XRD) patterns show the samples belong to single-phase cubic structure without any impurity phase. The magnetic properties (saturation magnetization and coercivity) of the samples have been investigated by VSM and found that the higher concentration of Li2CO3 reduces the hysteresis loss. DC resistivity increases with Li2CO3 contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are semiconductor. The dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime, which are due to the presence of resonance between applied frequency and hopping frequency of charge carriers. Notably, the loss peaks are shifted to the lower frequency with Li2CO3 additions.

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.

scholarly journals Microstructures, Magnetic Properties and Microwave Absorption Characteristics of Ti2+ -Mn4+Substituted Barium Hexaferrite

2016 ◽  
Vol 14 (1) ◽  
pp. 15 ◽  
Author(s):  
Maykel Manawan ◽  
Azwar Manaf ◽  
Bambang Soegijono ◽  
Asep Yudi Hercuadi
Keyword(s):  
Crystallite Size ◽  
Microwave Absorption ◽  
Single Phase ◽  
Barium Hexaferrite ◽  
Grain Morphology ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
X Ray ◽  
Xrd Patterns ◽  
Substituted Barium Hexaferrite

The effect of Ti2+-Mn4+substitution on microwave absorption has been studied for BaFe12-2xTixMnxO19 ferrite, where x varies from 0.2, 0.4, 0.6 and 0.8.Ti2+-Mn4+ ions were obtained from TiO and MnO2 precursors which were mechanically alloyed together with BaCO3 and Fe2O3 precursors. X-ray diffraction (XRD) patterns for sintered samples confirmed that the materials are consisted with single phase BHF structure. Unit cell volume and crystallite size was found increase with increasing x. Crystallite size for all samples below 70 nm, but the grain morphology shown that the grains is in range of 200 - 400 nm, which concluded that each grain are polycrystalline. The saturation magnetization is increases up to x = 0.4 and decrease for higher x values, while the coercivity remains decreases monotonically. These results were interpreted in terms of the site preferential occupation of Ti2+ and Mn4+ at low level substitution.These substitution revealed of enhanced reflection loss (RL) up to 25 dB forx=0.6.It suggested that the synthesized can be employed as effective microwave absorbers in various devices.

scholarly journals Phenomena Occurring upon the Sintering of a Mixture of Yttria–Zirconia Nanometric Powder and Sub-Micrometric Pure Zirconia Powder

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6937
Author(s):  
Kamil Wojteczko ◽  
Zbigniew Pędzich ◽  
Dariusz Zientara ◽  
Katarzyna Berent ◽  
Krzysztof Haberko
Keyword(s):  
Hydrothermal Treatment ◽  
Particle Morphology ◽  
X Ray Diffraction ◽  
Pure Zirconia ◽  
Back Scattering ◽  
Naoh Solution ◽  
Micrometer Size ◽  
Nanometric Powder ◽  
Zro2 System ◽  
Zirconia Powders

Mixtures of powders essentially differing in their particle morphology and size were applied to prepare polycrystals in a Y2O3-ZrO2 system. An yttria–zirconia solid solution nanometric powder with a Y2O3 concentration of 3.5% was prepared by subjecting co-precipitated gels to hydrothermal treatment at 240 °C. The crystallization occurred in distilled water. The pure zirconia powders composed of elongated and sub-micrometer size particles were also manufactured through the hydrothermal treatment of pure zirconia gel, although in this case, the process took place in the NaOH solution. Mixtures of the two kinds of powder were prepared so as to produce a mean composition corresponding to an yttria concentration of 3 mol%. Compacts of this powder mixture were sintered, and changes in phase composition vs. temperature were studied using X-ray diffraction. The dilatometry measurements revealed the behavior of the powder compact during sintering. The polished surfaces revealed the microstructure of the resulting polycrystal. Additionally, the electron back scattering diffraction technique (EBSD) allowed us to identify symmetry between the observed grains. Hardness, fracture toughness, and mechanical strength measurements were also performed.

scholarly journals SmBa1-xCaxCo2O5+d Layered Perovskite Cathodes for Intermediate Temperature-operating Solid Oxide Fuel Cells

2021 ◽  
Vol 8 ◽  
Author(s):  
Kyeong Eun Song ◽  
Sung Hun Woo ◽  
Seung Wook Baek ◽  
Hyunil Kang ◽  
Won Seok Choi ◽  
...  
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Single Phase ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Oxide Systems ◽  
Metal Insulator ◽  
A Value ◽  
Temperature Operating ◽  
Xrd Patterns

In SmBa1-xCaxCo2O5+d (x = 0.01, 0.03, 0.1, and 0.2, SBCCO) oxide systems calcined at 1100°C for 8 h, the XRD patterns of the SBCCO single phase were maintained in the cases of SmBa0.97Ca0.03Co2O5+d (SBCCO-0.97) and SmBa0.99Ca0.01Co2O5+d (SBCCO-0.99) compositions. In SmBa0.8Ca0.2Co2O5+d (SBCCO-0.8) and SmBa0.9Ca0.1Co2O5+d (SBCCO-0.9), CaCoSmO4 existed with the pattern SBCCO. SBCCO structures were identified as orthorhombic crystal structures because they showed splitting of the X-ray diffraction (XRD) peaks at 23.4°, 47.9°, and 59.1°.Typical metallic conduction behaviors were found in all measured compositions except SBCCO-0.8, which showed a metal-insulator transition (MIT) behavior. Compared to other SmBa1-xCaxCo2O5+d compositions, SBCCO-0.8 showed the highest electrical conductivity of 460 S/cm at 500°C. In particular, SBCCO-0.9 was found to have an excellent ASR characteristic of about 0.077 Ωcm2 at 700°C. The activation energy of SBCCO-0.9 was the lowest among SBCCO oxide systems with a value of 0.77 eV.

Synthesis and Characterization of Iron Oxide Nanostructured Particles in Na–Y Zeolite Matrix

2004 ◽  
Vol 19 (3) ◽  
pp. 930-936 ◽  
Author(s):  
Maxine Yee ◽  
Iskandar I. Yaacob
Keyword(s):  
Iron Oxide ◽  
Fine Particles ◽  
Gas Adsorption ◽  
Morphological Changes ◽  
X Ray Diffraction ◽  
Oxide Systems ◽  
Nanostructured Particles ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Adsorption Desorption

Formation of iron oxide nanoparticles within the internal cages of Na–Y zeolites was investigated. Sodium ions within the zeolites were replaced with iron(II) ions. Elemental composition studies showed a significant amount of iron in the exchanged sample. NaOH and dropwise additions of H2O2 at 60 °C triggered formation of zeolite–iron oxide systems. X-ray diffraction (XRD) patterns showed diminishing zeolite peaks along with evolution of peaks corresponding to γ-Fe2O3 and α-Fe2O3 with increasing NaOH concentration. Morphological changes from hexagonal-shaped zeolite to clusters of fine particles were observed under scanning electron microscope. Particles with about 15-nm diameter were detected by transmission electron microscopy. γ-Fe2O3 crystallites of 13.4 nm were determined from the broadening of XRD peaks. The magnetization curves of samples (precipitated using NaOH with concentrations of 2.0 M and above) showed absence of hysteresis and passed through the origin, indicating the particles are superparamagnetic. Gas adsorption–desorption measurement of the system precipitated with 2.0 M NaOH revealed a 26% increase in its specific surface area, indicating the presence of nanometer-sized particles within the zeolites.

The Microwave Electromagnetic Properties of Sr2+ Doped DyFeO3

2011 ◽  
Vol 197-198 ◽  
pp. 405-408
Author(s):  
Shao Teng Yan ◽  
Xiao Gu Huang ◽  
Feng Dai ◽  
Peng De Han ◽  
Li Xi Wang ◽  
...  
Keyword(s):  
Single Phase ◽  
Intermediate Phase ◽  
Electromagnetic Properties ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Xrd Patterns ◽  
Perovskite Type ◽  
Peak Value

Perovskite type ferrite doped with Sr2+, Dy1-xMxFeO3(x = 0.0, 0.05, 0.15, 0.25) were prepared by the conventional solid-state reaction. The structure and electromagnetic properties of the calcined samples were studied using powder X-ray diffraction (XRD, Rigaku D/Max-2500) and network analyzer (Agilent 8722ET). All the XRD patterns showed the single phase of the perovskite type ferrite without other intermediate phase when x≤0.25. The electromagnetic properties of the samples have been studied at the frequency range from 2 GHz to 18 GHz. The ε′ and ε′′ values were improved significantly. Both the values of ε′ and ε′′ increase with the increasing content of the doped cations Sr2+, and the peak value of ε′′ was about 2.2 at 12.1 GHz position when x = 0.25.

Structural and Photocatalytic Properties of Fe-Dope TiO2 Nanostructure Using the Hydrothermal Treatment Method

2013 ◽  
Vol 634-638 ◽  
pp. 2261-2263
Author(s):  
Khun Ngern Supunnee ◽  
Vatcharinkorn Mekla ◽  
Eakkarach Raksasri
Keyword(s):  
Optical Properties ◽  
Hydrothermal Treatment ◽  
Treatment Method ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Cuo Nanostructure ◽  
Uv Visible ◽  
Xrd Patterns ◽  
Top View

In this work optical properties of CuO nanostructure were studied. CuO nanostructure were synthesized by the hydrothermal treatment method. The structural and chemical natures of the obtained materials were studied using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and study optical properties by UV-visible spectral. The XRD patterns of the CuO nanostructures indicated that CuO phases (JCPDS 05- 0661). The top-view SEM images, it can be seen clearly that high-density, horizontally scattered nanorod were grown on the product prepared at concentration of NaOH (aq) 7.5 M at 180 C for 12 h. The spectral of UV-vis data recorded showed the strong cut off at 341 nm.

scholarly journals Investigations on Structural, Mechanical, and Dielectric Properties of PVDF/Ceramic Composites

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Anshuman Srivastava ◽  
Karun Kumar Jana ◽  
Pralay Maiti ◽  
Devendra Kumar ◽  
Om Parkash
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Single Phase ◽  
Extrusion Process ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
Composite State ◽  
X Ray ◽  
Embedded Capacitor ◽  
Xrd Patterns

Polymer ceramic composites are widely used for embedded capacitor application. In the present work PVDF has been used as a matrix and CCTO and LaCCTO have been used as reinforcement. Extrusion process has been used for the synthesis of composites. X-ray diffraction (XRD) patterns confirm the formation of single phase CCTO, and LaCCTO in its pure as well as composite state. It is found that La doping in CCTO considerably increases the dielectric constant and reduces the dielectric loss. A similar trend is observed in the composites with the increasing content of CCTO and LaCCTO.

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