Synthesis of ZrO2–Y6WO12 solid solution powders by a polymerized complex method

1998 ◽  
Vol 13 (4) ◽  
pp. 939-943 ◽  
Author(s):  
Junfeng Ma ◽  
Masahiro Yoshimura ◽  
Masato Kakihana ◽  
Masatomo Yashima
Keyword(s):  
Solid Solution ◽  
Crystallite Size ◽  
Surface Area ◽  
Solid Solutions ◽  
Lattice Parameter ◽  
Cubic Phase ◽  
Complex Method ◽  
Amorphous Precursor ◽  
Fine Powders ◽  
Polymerized Complex Method

A series of solid solutions (1 − x) ZrO2 · xY0.857 W0.143 O1.714 (1/7Y6WO12) of metastable cubic phase were synthesized at 800 °C through a polymerized complex method. Lattice parameter a0 of solid solutions varies linearly with Y0.857 W0.143 O1.714 content (x). Crystallization began to occur above 400 °C from amorphous precursor to yield at 800 °C fine powders of 6–10 nm and 19–40 m2/g for crystallite size and surface area, respectively.

scholarly journals Characterization of Mechanically Alloyed Nanocrystalline Fe(Al): Crystallite Size and Dislocation Density

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
M. Mhadhbi ◽  
M. Khitouni ◽  
L. Escoda ◽  
J. J. Suñol ◽  
M. Dammak
Keyword(s):  
Solid Solution ◽  
Dislocation Density ◽  
Crystallite Size ◽  
Average Crystallite Size ◽  
High Energy ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
High Energy Ball Mill

A nanostructured disordered Fe(Al) solid solution was obtained from elemental powders of Fe and Al using a high-energy ball mill. The transformations occurring in the material during milling were studied with the use of X-ray diffraction. In addition lattice microstrain, average crystallite size, dislocation density, and the lattice parameter were determined. Scanning electron microscopy (SEM) was employed to examine the morphology of the samples as a function of milling times. Thermal behaviour of the milled powders was examined by differential scanning calorimetry (DSC). The results, as well as dissimilarity between calorimetric curves of the powders after 2 and 20 h of milling, indicated the formation of a nanostructured Fe(Al) solid solution.

Synthesis of Metastable Tetragonal (t') Zirconia-Ceria Solid Solutions by the Polymerized Complex Method

1994 ◽  
Vol 77 (10) ◽  
pp. 2773-2776 ◽  
Author(s):  
Masatomo Yashima ◽  
Katsuya Ohtake ◽  
Masato Kakihana ◽  
Masahiro Yoshimura
Keyword(s):  
Solid Solutions ◽  
Complex Method ◽  
Ceria Solid Solutions ◽  
Polymerized Complex Method

Low temperature stabilization of zirconia by Mn through Co-precipitated hydroxide gel route

1994 ◽  
Vol 9 (4) ◽  
pp. 837-840 ◽  
Author(s):  
A. Keshavaraja ◽  
A. V. Ramaswamy
Keyword(s):  
Low Temperature ◽  
Surface Area ◽  
Linear Correlation ◽  
Lattice Parameter ◽  
Cubic Phase ◽  
Gel Formation ◽  
Temperature Stabilization ◽  
Subsequent Calcination ◽  
Mn Content

Stabilization of zirconia into cubic phase is achieved by partly substituting Zr4+ with Mn4+ ions (5–30 mole %) via hydroxide gel formation and subsequent calcination at 773 K and is supported by XRD and IR data. A linear correlation between the lattice parameter and the Mn content confirms the incorporation of Mn into ZrO2. The XPS and TPR results provide some evidence for the presence of Mn4+ ions in these samples which have a surface area of about 100 m2 g-1 and are stable in the cubic phase up to 973 K. On reduction above 973 K, the cubic phase is stabilized probably by Mn2+ ions.

scholarly journals Facile Synthesis of Spherical Flake-shaped CuO Nanostructure and Its Characterization towards Solar Cell Application

2021 ◽  
Vol 18 (18) ◽  
Author(s):  
Jemibha PAULDURAI ◽  
Ahila Mudisoodum PERUMAL ◽  
Dhanalakshmi JEYARAJA ◽  
Panimaya Valan Rakkini AMAL
Keyword(s):  
Solar Cell ◽  
Crystallite Size ◽  
Surface Area ◽  
Average Crystallite Size ◽  
Lattice Parameter ◽  
Peak Position ◽  
Cuo Nanoparticles ◽  
Precipitation Method ◽  
Solar Cell Application ◽  
Morphological Studies

The aim of this work is to synthesis CuO nanoparticles and investigates their eminent properties to identify their diverse application capability in the field of solar cells.  In this work, CuO nanoparticles were synthesized by precipitation method using Copper (II) nitrate and Copper (II) chloride. Surface effects due to defects, structural properties related through lattice parameter, and crystallite sizes of nanoparticles have been identified from XRD. The crystal plane and reflection peak position was calculated using Bragg’s law. It showed that CuO nanoparticles have a monoclinic structure, and that the average crystallite size of CuO nanoparticles was 28.82 nm. n-type semiconductor behavior had a direct band of Eg = 1.465(2) eV, analyzed from optical studies by DRS. The band gap of the sample was determined from the reflectance spectra using Kubelka-Munk (K-M) function. Elements present were found through absorption peak of FTIR. The blue shifts observed in FTIR spectra in CuO nanoparticles were compared with that of bulk CuO, and absorption band agreed with XRD results.  Morphological studies revealed the formation of spherical flake-shaped formation of CuO. It had a higher surface area and was well-suited to solar cell applications. HIGHLIGHTS The CuO nanoparticles were synthesized by precipitation method The average crystallite size of CuO nanoparticles obtained in the range of 28.82 nm Spherical flake-shaped nanostruture with higher surface area formed in this method Optical property of CuO (Eg = 1.465 eV) and good electron mobility make it a suitable solar cell absorber material GRAPHICAL ABSTRACT

scholarly journals The Impact of Cation Distribution on The Structural and Magnetic Properties of Nonstoichiometric Co0.5Ni0.5+xFe2-xO4 Nanoferrites

2021 ◽  
Author(s):  
Adel Maher Wahba ◽  
Bahaa Eldeen M. Moharam ◽  
Aya Fayez Mahmoud
Keyword(s):  
Magnetic Properties ◽  
Crystallite Size ◽  
Cation Distribution ◽  
Hysteresis Loops ◽  
Lattice Parameter ◽  
Cubic Phase ◽  
Ir Frequencies ◽  
Structural And Magnetic Properties ◽  
Xrd Patterns ◽  
The Impact

Abstract In this work, the impact of nonstoichiometric substitution of Fe3+ cations by Ni2+ ones on the structural and magnetic properties of Co0.5Ni0.5+xFe2-xO4 (0.0 ≤ x ≤ 0.4) nanoferrites synthesized by citric autocombustion method. The cubic phase purity for sintered samples were verified by XRD patterns and FTIR spectra. The crystallite size and microstrain were deduced using Williamson-Hall method. The estimated crystallite size ranges from 55 to 89 nm in agreement with TEM microimages. Hysteresis loops traced using VSM prevailed a regular reduction of saturation magnetization with Ni substitution. Relied on the experimental data of XRD, FTIR, and VSM, cation distribution has been suggested, according to which the nonstoichiometric substitution was compensated by the appearance of higher valance states of Fe, Ni, and Co cations. The suggested cation distribution successfully explained the recorded data of lattice parameter, crystallite size, IR frequencies, magnetization and coercivity.

X-ray study of CuGa x In1−x Se2 solid solutions

1989 ◽  
Vol 22 (6) ◽  
pp. 578-583 ◽  
Author(s):  
D. K. Suri ◽  
K. C. Nagpal ◽  
G. K. Chadha
Keyword(s):  
Solid Solution ◽  
Binary System ◽  
Crystallite Size ◽  
Solid Solutions ◽  
Lattice Parameters ◽  
Chalcopyrite Structure ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
A Value

The semiconducting compound CuGa x In1 − x Se2 crystallizes in the chalcopyrite structure (space group I{\bar 4}2d, Z = 4). The X-ray powder data for x = 1, 0.75, 0.6, 0.5, 0.4, 0.25 and 0.0 have been collected and it is found that the lattice parameters a and c and their ratio c/a vary linearly with x. Thus the composition of any chalcopyrite in the pseudo-binary system CuGaSe2 and CuInSe2 can be obtained from the accurate lattice parameters. The crystallite size determined from the (112) plane is minimum for x = 0.50 (~ 1000 Å) and away from x = 0.50 it increases. A value of u = 0.240 (5) has been established for fixing the Se-atom positions in the CuGa0.5In0.5Se2 solid solution. The JCPDS Diffraction File No. for CuInSe2 is 40-1487 and for CuGa0.5In0.5Se2 is 40-1488.

scholarly journals The Structural and Magnetic Properties of Gadolinium Doped CoFe2O4Nanoferrites

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Qing Lin ◽  
Jinpei Lin ◽  
Yun He ◽  
Ruijun Wang ◽  
Jianghui Dong
Keyword(s):  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Crystallite Size ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Lattice Parameter ◽  
Cubic Phase ◽  
Structural And Magnetic Properties

Gadolinium substituted cobalt ferrite CoGdxFe2−xO4(x= 0, 0.04, 0.08) powders have been prepared by a sol-gel autocombustion method. XRD results indicate the production of a single cubic phase of ferrites. The lattice parameter increases and the average crystallite size decreases with the substitution of Gd3+ions. SEM shows that the ferrite powers are nanoparticles. Room temperature Mössbauer spectra of CoGdxFe22−xO4are two normal Zeeman-split sextets, which display ferrimagnetic behavior. The saturation magnetization decreases and the coercivity increases by the Gd3+ions.

Preparation of TiC/Ti3SiC2 Composite by Sintering Mechanical Alloyed Ti–Si–C Powder Mixtures

2020 ◽  
Vol 20 (7) ◽  
pp. 4580-4586
Author(s):  
Manuel Fellipe R. Pais Alves ◽  
Claudinei dos Santos ◽  
Bruno Xavier de Freitas ◽  
Alfeu Saraiva Ramos ◽  
Erika Coaglia Trindade Ramos ◽  
...  
Keyword(s):  
Particle Size ◽  
Mechanical Alloying ◽  
Crystallite Size ◽  
Average Particle Size ◽  
Lattice Parameter ◽  
Unit Cell ◽  
High Fracture Toughness ◽  
Cubic Phase ◽  
Average Particle ◽  
Crystalline Phases

The present work aims to evaluate the crystalline phases and microstructure of a TiC–Ti3SiC2 ceramic composite, obtained by mechanical alloying of Ti, C and Si powders and subsequent sintering. A mechanical alloying technique in a planetary ball mill for 1, 10, 50, 100 and 200 h using Ti, Si and C powders with molar ratios of 3:1:2 as feedstock in argon (Ar) gas was employed to prepare nano-sized Ti–Si–C powders. TiC crystallite size and lattice strain were evaluated by X-ray diffraction analysis (XRD) and the morphological characteristics and particle size distribution were examined using scanning electron microscope (SEM). After milling, a reduction of the average particle size and crystallinity is observed. Furthermore, after 10 h of milling time, TiC starts to crystallize. The powder mixture obtained after 200 h of milling was compacted and sintered at 1200 °C under controlled atmosphere, for 15 min, 2 h or 4 h with a heating rate of 5 °C/min. Almost full densification of samples sintered for 2 h and 4 h has been achieved, with relative densities close to 98.8±0.2% and TiC and Ti3SiC2 as crystalline phases with an average crystallite size of TiC near 0.7 μm. Rietveld refinement indicates that the majority TiC-cubic phase (>85 vol%) presents a unit cell volume of 8.03 nm3 after sintering at 1200 °C. Despite the maintenance of the volume of the hexagonal unit cell of Ti3SiC2, (15.05 nm3), the increase of the isothermal sintering time resulted in an increase of the lattice parameter “a”, from 0.315 nm to 0.320 nm, and a reduction of the lattice parameter “c” from 1.750 nm to 1.705 nm. The control of the changes in the residual stresses within the TiC matrix and the Ti3SiC2 precipitates, which is associated with the deformation in the lattice parameters, must be controlled to achieve high fracture toughness in the composite.

Low Density Titanium Alloys by Non-Equilibrium Processing.

1995 ◽  
Vol 400 ◽  
Author(s):  
D.M.J. Wilkes ◽  
P.S. Goodwin ◽  
C.M. Ward-Close ◽  
K. Bagnall ◽  
J. Steeds
Keyword(s):  
Solid Solution ◽  
High Resolution ◽  
Solid Solutions ◽  
Lattice Parameter ◽  
Argon Atmosphere ◽  
Low Density ◽  
Equilibrium Solubility ◽  
High Resolution Tem ◽  
High Vapour Pressure ◽  
Clean Atmosphere

AbstractHigh levels of Mg solid solution in Ti have been achieved by mechanical alloying in a clean atmosphere. The equilibrium solubility of magnesium in titanium is very low and processing of these alloys by conventional routes is not possible due to the high vapour pressure of Mg and alloys of Ti and Mg have only been previously achieved by vapour quenching.Contamination during milling was avoided by processing under a high purity argon atmosphere in sealed vials. Lattice parameter measurements and SEM observations suggested that complete solid solutions were achieved in alloys up to 24wt% Mg after 48h milling. For one alloy this was confirmed by high resolution TEM which showed extremely fine Ti grains in which Mg was homogeneously distributed with no clustering or precipitation.

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