scholarly journals Investigations of LiNb1−xTaxO3 Nanopowders Obtained with Mechanochemical Method

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 755
Author(s):  
Leonid Vasylechko ◽  
Volodymyr Sydorchuk ◽  
Andrey Lakhnik ◽  
Yuriy Suhak ◽  
Damian Wlodarczyk ◽  
...  
Keyword(s):  
Single Phase ◽  
Structural Parameters ◽  
High Energy ◽  
Optimal Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Dependences ◽  
Scattering Spectra ◽  
Energy Ball ◽  
Raman Scattering Spectra

Nanocrystalline compounds LiNb1−xTaxO3 of various compositions (x = 0, 0.25, 0.5, 0.75, 1) were synthesized by high-energy ball milling of the initial materials (Li2CO3, Nb2O5, Ta2O5) and subsequent high-temperature annealing of the resulting powders. Data on the phase composition of the nanopowders were obtained by X-ray diffraction methods, and the dependence of the structural parameters of LiNb1−xTaxO3 compounds on the value of x was established. As a result of the experiments, the optimal parameters of the milling and annealing runs were determined, which made it possible to obtain single-phase compounds. The Raman scattering spectra of LiNb1−xTaxO3 compounds (x = 0, 0.25, 0.5, 0.75, 1) have been investigated. Preliminary experiments have been carried out to study the temperature dependences of their electrical conductivity.

The Transformation of Co-Rich Alloys Produced by Mechanical Alloying

2006 ◽  
Vol 509 ◽  
pp. 135-140
Author(s):  
Francisco Cruz-Gandarilla ◽  
R. Gayosso-Armenta ◽  
J. Gerardo Cabañas-Moreno ◽  
Heberto Balmori-Ramírez
Keyword(s):  
Single Phase ◽  
Intermetallic Phase ◽  
High Energy ◽  
Inert Atmosphere ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Powder Mixtures ◽  
X Ray ◽  
Heat Treated ◽  
Energy Ball

Elemental powder mixtures of Co and Ti were subjected to high-energy ball milling in order to produce mechanically alloyed powders with nominal compositions Co64Ti36, Co67Ti33, Co70Ti30, Co73Ti27, Co76Ti24 and Co85Ti15. The mechanically alloyed powders were treated during 30 minutes in inert atmosphere at temperatures in the range 300 – 700 °C. Both the as-milled powders as well as those subjected to heat treatments have been characterized by x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray spectrometry and differential thermal analysis. As-milled products consist mostly of agglomerated powders with a size between 10 and 80 µm which give an amorphous-like diffraction pattern, except for the Co85Ti15 sample whose pattern presents the characteristic peaks of the Co3Ti intermetallic phase. The transformation of the asmilled powders occurs at temperatures in the range of about 530 – 670 °C with clearly observed exothermic events. The Co3Ti phase is found in all heat treated samples, together with fcc-Co (in Co76Ti24 and Co85Ti15) or the hexagonal Co2Ti intermetallic phase (in Co64Ti36, Co67Ti33 and Co70Ti30); the Co73Ti27 sample was essentially single-phase Co3Ti after heating to 700 °C. Our results suggest the occurrence of crystallization of an amorphous phase in two overlapping stages during heating of the mechanically alloyed powders.

scholarly journals Термодинамические свойства оксипентафторида ванадия (IV), (NH-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-VOF-=SUB=-5-=/SUB=-

2020 ◽  
Vol 62 (7) ◽  
pp. 1123
Author(s):  
Е.В. Богданов ◽  
Е.И. Погорельцев ◽  
А.В. Карташев ◽  
М.В. Горев ◽  
М.С. Молокеев ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Photoelectron Spectroscopy ◽  
Single Phase ◽  
Dielectric Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Limits Of Stability ◽  
Three Phase ◽  
Temperature Dependences ◽  
Spectroscopy Studies

Abstract The (NH_4)_3VOF_5 crystals have been synthesized and their homogeneity and single-phase structure has been established by the X-ray diffraction, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy studies. The investigations of the temperature dependences of specific heat, entropy, strain, and pressure susceptibility show the occurrence of three phase transitions caused by the structural transformations in the (NH_4)_3VOF_5 crystals. The T – p phase diagram shows the temperature limits of stability of the crystalline phases implemented in (NH_4)_3VOF_5. The optical and dielectric studies disclose the ferroelastic nature of the phase transitions. An analysis of the experimental data together with the data on the isostructural (NH_4)_3VO_2F_4 crystal makes it possible to distinguish the physical properties of oxyfluorides containing vanadium of different valences (IV and V).

Mössbauer, X-ray diffraction and magnetization studies of Fe–Mn–Al–Nb alloys prepared by high energy ball milling

2006 ◽  
Vol 168 (1-3) ◽  
pp. 1057-1063 ◽  
Author(s):  
Ligia E. Zamora ◽  
G. A. Perez Alcazar ◽  
J. M. Greneche ◽  
S. Suriñach
Keyword(s):  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Ball

Mechanism of Achieving Nanocrystalline AIRu By Ball Milling

1988 ◽  
Vol 132 ◽  
Author(s):  
E. Hellstern ◽  
H. J. Fecht ◽  
C. Garland ◽  
W. L. Johnson ◽  
W. M. Keck
Keyword(s):  
Ball Milling ◽  
Crystal Size ◽  
Shear Bands ◽  
Nanocrystalline Structure ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Energy Ball ◽  
Small Grains

ABSTRACTWe investigated through X- ray diffraction and transmission electron microscopy the crystal refinement of the intermetallic compound AIRu by high- energy ball milling. The deformation process causes a decrease of crystal size to 5–7 rum and an increase of atomic level strain. This deformation is localized in shear bands with a thickness of 0.5 to 1 micron. Within these bands the crystal lattice breaks into small grains with a typical size of 8–14 rum. Further deformation leads to a final nanocrystalline structure with randomly oriented crystallite grains separated by high- angle grain boundaries.

Variation of Tungsten Oxide Reduction Mode Using Different High Energy Milling Conditions

2012 ◽  
Vol 727-728 ◽  
pp. 206-209
Author(s):  
Osvaldo Mitsuyuki Cintho ◽  
H.I. Tsai ◽  
M. Bär ◽  
M. de Castro ◽  
E.F. Monlevade ◽  
...  
Keyword(s):  
Tungsten Oxide ◽  
Milling Time ◽  
Xrd Analysis ◽  
High Energy ◽  
Oxide Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Ball ◽  
Fast Increase ◽  
Stoichiometric Proportion

High energy ball milling has been used like alternative route for processing of materials. In the present paper, the reduction of tungsten oxide by aluminum in order to obtain metallic tungsten was studied using a SPEX type high energy mill. A powdered mixture of WO3and metallic aluminum, weighed according to the stoichiometric proportion with an excess 10% Al, was processed with hardened steel utensils using a 1:6 powder-to-ball ratio. The processing was carried out with milling jar temperature measurement in order to detect the reaction type. The temperature evaluation indicated the self-propagating reaction occurrence by fast increase of the jar temperature after a short milling time. The tungsten oxide reduction was verified by X-Ray Diffraction (XRD) analysis and the milling products were characterized by Scanning Electron Microscopy (SEM). The results were slightly different from the literature due to the mill type and milling parameters used in the work.

scholarly journals Composition versus Wear Behaviour of Air Plasma Sprayed NiCr–TiB2–ZrB2 Composite Coating

Coatings ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 273
Author(s):  
Ning Zhang ◽  
Nannan Zhang ◽  
Sheng Guan ◽  
Shumei Li ◽  
Guangwei Zhang ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Composite Coating ◽  
High Hardness ◽  
High Energy ◽  
Wear Behaviour ◽  
Air Plasma ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Ball ◽  
Plasma Sprayed

The NiCr–TiB2–ZrB2 composite coating was deposited on the surface of blades made of steel (SUS304) using high-energy ball milling technology and air plasma spraying technology, which aimed to relieve the wear of the blades during operation. The influence of titanium diboride (TiB2) and zirconium diboride (ZrB2) on the microstructure and wear resistance of the coatings was investigated by X-ray diffraction, scanning electron microscopy, Vickers microhardness tester, and a wear tester. The results showed that the TiB2 and ZrB2 particles were unevenly distributed in the coatings and significantly increased the hardness and anti-wear, which contributed to their ultra-high hardness and extremely strong ability to resist deformation. The performance of the coatings was improved with the increase of the number of ceramic phases, while the hardness and wear resistance of the coating could reach their highest value when the TiB2 and ZrB2 respectively took up 15 wt.% of the total mass of the powder.

A Study of Amorphous Erbium-Based Alloys Formed by Near-Isothermal Cold-Rolling of Elemental Composites

1985 ◽  
Vol 58 ◽  
Author(s):  
Michael Atzmon ◽  
Karl M. Unruh ◽  
Constantin Politis ◽  
William L. Johnson ◽  
W. M. Keck
Keyword(s):  
Cold Rolling ◽  
Single Phase ◽  
Enthalpy Of Mixing ◽  
High Energy ◽  
Distribution Functions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Energy Ball ◽  
Constituent Elements ◽  
Good Agreement

ABSTRACTWe report the formation of single-phase amorphous Cu-Er and Ni-Er alloys in bulk form by cold-rolling of composites prepared from elemental foils. As for previously reported cases of metallic glass formation by solid-state reaction, the driving force for the reaction is the negative enthalpy of mixing of the constituent elements. It occurs during deformation close to room temperature. Amorphous Cu7 2 Er2 8 was also produced by high-energy ball-milling of the elemental powders as well as by sputtering and liquid quenching. The alloys obtained were characterized by means of differential scanning calorimetry and x-ray diffraction. The crystallization behavior observed and the radial distribution functions obtained showed good agreement between the alloys prepared by different methods.

scholarly journals Structural and magnetic properties of mechanochemically synthesized nanosized yttrium titanate

2012 ◽  
Vol 66 (3) ◽  
pp. 309-315 ◽  
Author(s):  
Tanja Barudzija ◽  
Alexey Gusev ◽  
Dragana Jugovic ◽  
Milena Marinovic-Cincovic ◽  
Miroslav Dramicanin ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Single Phase ◽  
High Energy ◽  
Argon Atmosphere ◽  
Molar Ratio ◽  
Superconducting Quantum Interference Device ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Mean ◽  
First Time

Nanosized perovskite YTiO3 with the mean crystallite size of 18 nm was synthesized for the first time by mechanochemical treatment. The mechanochemical solid state reaction between commercial Y2O3 powder and mechanochemically synthesized TiO powder in molar ratio 0.5:1 was completed for 3 h in a high-energy planetary ball mill in argon atmosphere. The heating in vacuum at 1150 ?C for 12 h transforms nanosized YTiO3 to a well-crystallized single-phase perovskite YTiO3. Both samples were characterized by X-ray diffraction (XRD) and thermogravimetric (TGA/DTA) analyses, as well as superconducting quantum interference device magnetometer (SQUID) measurements.

Microstructural Transformations of an Amorphous Fe90 Zr10 Alloy Induced by High-Energy Ball-Milling

2006 ◽  
Vol 510-511 ◽  
pp. 698-701
Author(s):  
Pyuck Pa Choi ◽  
Young Soon Kwon ◽  
Ji Soon Kim ◽  
Dae Hwan Kwon
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
High Energy ◽  
High Energy Ball Milling ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Melt Spun ◽  
Energy Ball ◽  
Induced Crystallization

Mechanically induced crystallization of an amorphous Fe90Zr10 alloy was studied by means of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Under high-energy ball-milling in an AGO-2 mill, melt-spun Fe90Zr10 ribbons undergo crystallization into BCC α- Fe(Zr). Zr atoms are found to be solved in the Fe(Zr) grains up to a maximum supersaturation of about 3.5 at.% Zr, where it can be presumed that the remaining Zr atoms are segregated in the grainboundaries. The decomposition degree of the amorphous phase increases with increasing milling time and intensity. It is proposed that the observed crystallization is deformation-induced and rather not attribute to local temperature rises during ball-collisions.

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