scholarly journals Chemical synthesis of nanostructured magnetic hardened alloy of the Nd-Fe-B system

2021 ◽  
Vol 12 (2-2021) ◽  
pp. 11-13
Author(s):  
O. E. Abdurakhmonov ◽  
◽  
M. E. Alisultanov ◽  
E. V. Yurtov ◽  
◽  
...  
Keyword(s):  
Particle Size ◽  
Chemical Synthesis ◽  
Diffusion Process ◽  
Chemical Deposition ◽  
Hydrogen Atmosphere ◽  
Magnetic Alloys ◽  
Hardened Alloy ◽  
Average Size

Hard magnetic nanopowders of the Nd15Fe78B7 alloy were synthesized from mixtures of Nd, Fe and Fe-B oxides with CaH2 in a hydrogen atmosphere at 800 °C by a reduction-diffusion process. Nd, Fe, Fe-B oxides were synthesized by chemical deposition. The resulting particles had a granular shape with an average size: Nd2O3 — 50 nm, Fe2O3 — 95 nm, Fe3BO6 — 57 nm. The particle size of the Nd15Fe78B7 alloy was 45–140 nm. It is shown that the proposed method is suitable for obtaining nanopowders of hard magnetic alloys of the Nd-Fe-B system.

scholarly journals Obtaining Silicon Oxide Nanoparticles Doped with Fluorine and Gold Particles by the Pulsed Plasma-Chemical Method

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Galina Kholodnaya ◽  
Roman Sazonov ◽  
Denis Ponomarev ◽  
Igor Zhirkov
Keyword(s):  
Chemical Synthesis ◽  
Silicon Oxide ◽  
Fine Particles ◽  
Chemical Reactor ◽  
Beam Diameter ◽  
Pulsed Plasma ◽  
Plasma Chemical ◽  
Plasma Chemical Synthesis ◽  
Transmission Electron ◽  
Average Size

This paper presents a study on pulsed plasma-chemical synthesis of fluorine- and gold-doped silicon oxide nanopowder. The gold- and fluorine-containing precursors were gold chloride (AuCl3) and sulphur hexafluoride (SF6). Pulsed plasma-chemical synthesis is realized on the laboratory stand, including a plasma-chemical reactor and TEA-500 electron accelerator. The parameters of the electron beam are as follows: 400–450 keV electron energy, 60 ns half-amplitude pulse duration, up to 200 J pulse energy, and 5 cm beam diameter. We confirmed the composite structure of SixOy@Au by using transmission electron microscopy and energy-dispersive spectroscopy. We determined the chemical composition and morphology of synthesized SixOy@Au and SixOy@F nanocomposites. The material contained a SixOy@Au carrier with an average size of 50–150 nm and a shell of fine particles with an average size of 5–10 nm.

scholarly journals ZnWO4 Nanoparticle Scintillators for High Resolution X-ray Imaging

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1721
Author(s):  
Heon Yong Jeong ◽  
Hyung San Lim ◽  
Ju Hyuk Lee ◽  
Jun Heo ◽  
Hyun Nam Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
High Resolution ◽  
Tungsten Oxide ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
X Ray ◽  
X Ray Imaging ◽  
Average Size ◽  
And Tungsten

The effect of scintillator particle size on high-resolution X-ray imaging was studied using zinc tungstate (ZnWO4) particles. The ZnWO4 particles were fabricated through a solid-state reaction between zinc oxide and tungsten oxide at various temperatures, producing particles with average sizes of 176.4 nm, 626.7 nm, and 2.127 μm; the zinc oxide and tungsten oxide were created using anodization. The spatial resolutions of high-resolution X-ray images, obtained from utilizing the fabricated particles, were determined: particles with the average size of 176.4 nm produced the highest spatial resolution. The results demonstrate that high spatial resolution can be obtained from ZnWO4 nanoparticle scintillators that minimize optical diffusion by having a particle size that is smaller than the emission wavelength.

A Convenient Method for Preparing Well-Dispersed Er2Zr2O7 Nanocrystals

2010 ◽  
Vol 123-125 ◽  
pp. 611-614 ◽  
Author(s):  
Yu Ping Tong ◽  
Rui Zhu Zhang ◽  
Shun Bo Zhao ◽  
Chang Yong Li
Keyword(s):  
Particle Size ◽  
Combustion Synthesis ◽  
Crystal Size ◽  
Lattice Distortion ◽  
Combustion Method ◽  
Treatment Temperature ◽  
Synthesis Process ◽  
Thermal Treatment Temperature ◽  
Average Size ◽  
Xrd And Tem

Well-dispersed fluorite Er2Zr2O7 nanocrystals have been successfully prepared by a convenient salt-assistant combustion method. The effects of calcinations temperature and salt category on the characteristics of the products were investigated by XRD and TEM. The thermal treatment temperature has an important effect on crystal size and lattice distortion of the nanocrystals. The experiment showed that the introduction of salt in the combustion synthesis process resulted in the formation of well-dispersed Er2Zr2O7 nanocrystals. The average size was 30 nm and was in agreement with the XRD result, which indicated that the nanocrystals were uniform in particle size distribution. Moreover, the possible formation process in the salt-assisted combustion synthesis was also analyzed.

scholarly journals Modulation of Lithium Disilicate Translucency through Heat Treatment

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2094
Author(s):  
Seok-Ki Jung ◽  
Dae Woon Kim ◽  
Jeongyol Lee ◽  
Selvaponpriya Ramasamy ◽  
Hyun Sik Kim ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Light Scattering ◽  
Flexural Strength ◽  
Control Method ◽  
Light Transmission ◽  
Lithium Disilicate ◽  
Lower Heat ◽  
Average Size ◽  
Ball Test

The aim of this study was to present a control method for modulating the translucency of lithium disilicate ceramics through thermal refinement. Identical lithium disilicate blocks were thermally refined using four different heat treatment schedules, and the microstructure, translucency, and flexural strength of the ceramics were investigated in detail by SEM, spectroscopy, and a piston-on-three-ball test. The results showed that ceramics treated under higher heat had larger grains, with an average size between 240 and 1080 nm. In addition, a higher transmittance of all wavelengths was observed in ceramics treated under lower heat, and the transmittance in the 550 nm wavelength ranged from 27 to 34%. The results suggest that the translucency of ceramics can be modified through thermal refinement under two conditions: (1) the particle size of the ceramic is small enough to achieve minimal grain-boundary light scattering, and (2) the percentage of particles allowing visible light transmission is altered by the heat treatment.

Strengthening Particle Size Effect on Residual Stresses in Dispersion-Hardened Alloy

2018 ◽  
Vol 61 (5) ◽  
pp. 962-973 ◽  
Author(s):  
O. V. Matvienko ◽  
O. I. Daneyko ◽  
T. A. Kovalevskaya
Keyword(s):  
Particle Size ◽  
Residual Stresses ◽  
Size Effect ◽  
Particle Size Effect ◽  
Hardened Alloy

scholarly journals Effect of the polymeric coating over Fe3O4 particles used for magnetic separation

2010 ◽  
Vol 8 (5) ◽  
pp. 1041-1046 ◽  
Author(s):  
Raúl Reza ◽  
Carlos Martínez Pérez ◽  
Claudia Rodríguez González ◽  
Humberto Romero ◽  
Perla García Casillas
Keyword(s):  
Particle Size ◽  
Magnetite Nanoparticles ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Polymeric Coating ◽  
Average Particle ◽  
Synthesis Conditions ◽  
Aging Conditions ◽  
Magnetite Particles ◽  
Average Size

AbstractIn this work, the synthesis of magnetite nanoparticles by two variant chemical coprecipitation methods that involve reflux and aging conditions was investigated. The influence of the synthesis conditions on particle size, morphology, magnetic properties and protein adsorption were studied. The synthesized magnetite nanoparticles showed a spherical shape with an average particle size directly influenced by the synthesis technique. Particles of average size 27 nm and 200 nm were obtained. When the coprecipitation method was used without reflux and aging, the smallest particles were obtained. Magnetite nanoparticles obtained from both methods exhibited a superparamagnetic behavior and their saturation magnetization was particle size dependent. Values of 67 and 78 emu g−1 were obtained for the 27 nm and 200 nm magnetite particles, respectively. The nanoparticles were coated with silica, aminosilane, and silica-aminosilane shell. The influence of the coating on protein absorption was studied using Bovine Serum Albumin (BSA) protein.

Chemical synthesis of Nd2Fe14B hard phase magnetic nanoparticles with an enhanced coercivity value: effect of CaH2 amount on the magnetic properties

2016 ◽  
Vol 40 (12) ◽  
pp. 10181-10186 ◽  
Author(s):  
Ji Hun Jeong ◽  
Hao Xuan Ma ◽  
Doyun Kim ◽  
Chang Woo Kim ◽  
In Ho Kim ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Nanoparticles ◽  
Chemical Synthesis ◽  
Diffusion Process ◽  
Hard Phase ◽  
Synthesis Route ◽  
Value Effect ◽  
Chemical Synthesis Route ◽  
And Diffusion

Nd2Fe14B hard phase magnetic nanoparticles were successfully synthesized using a chemical synthesis route followed by a reduction and diffusion process without consuming a large amount of energy.

scholarly journals Formation of ZnO/Zn0.5Cd0.5Se Alloy Quantum Dots in the Presence of High Oleylamine Contents

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 999
Author(s):  
Yi-An Chen ◽  
Kuo-Hsien Chou ◽  
Yi-Yang Kuo ◽  
Cheng-Ye Wu ◽  
Po-Wen Hsiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Particle Size ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Average Size ◽  
Alloy Quantum Dots ◽  
First Time

To the best of our knowledge, this report presents, for the first time, the schematic of the possible chemical reaction for a one-pot synthesis of Zn0.5Cd0.5Se alloy quantum dots (QDs) in the presence of low/high oleylamine (OLA) contents. For high OLA contents, high-resolution transmission electron microscopy (HRTEM) results showed that the average size of Zn0.5Cd0.5Se increases significantly from 4 to 9 nm with an increasing OLA content from 4 to 10 mL. First, [Zn(OAc)2]–OLA complex can be formed by a reaction between Zn(OAc)2 and OLA. Then, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) data confirmed that ZnO is formed by thermal decomposition of the [Zn(OAc)2]–OLA complex. The results indicated that ZnO grew on the Zn0.5Cd0.5Se surface, thus increasing the particle size. For low OLA contents, HRTEM images were used to estimate the average sizes of the Zn0.5Cd0.5Se alloy QDs, which were approximately 8, 6, and 4 nm with OLA loadings of 0, 2, and 4 mL, respectively. We found that Zn(OAc)2 and OLA could form a [Zn(OAc)2]–OLA complex, which inhibited the growth of the Zn0.5Cd0.5Se alloy QDs, due to the decreasing reaction between Zn(oleic acid)2 and Se2−, which led to a decrease in particle size.

IR spectra of powder hematite: effects of particle size and shape

Clay Minerals ◽  
1981 ◽  
Vol 16 (4) ◽  
pp. 375-382 ◽  
Author(s):  
Jose L. Rendon ◽  
Carlos J. Serna
Keyword(s):  
Particle Size ◽  
Ir Spectra ◽  
Ir Absorption ◽  
Surface Mode ◽  
Absorption Bands ◽  
Size And Shape ◽  
Ir Absorption Spectra ◽  
Theoretical Predictions ◽  
Particle Size And Shape ◽  
Average Size

AbstractHematites obtained by heating goethite gave different IR absorption spectra depending on the temperature of formation. Hematites formed between 250–600°C consisted of lath-like crystals (average size 0.4 ×0.08 µm) and showed, in accordance with theoretical predictions, very similar IR spectra whose absorption bands could all be assigned to surface mode vibrations. However, significantly different IR spectra were given by hematites formed between 700–950°C, the differences being correlated with variations in the size and shape of the particles. Differences observed in the IR spectra of powder hematite do not therefore justify new names for the mineral, as have been proposed in the literature.

Formation threshold and structural evolution of molybdenum nanocrystals with sputtering pressure

1991 ◽  
Vol 6 (1) ◽  
pp. 8-10 ◽  
Author(s):  
G. M. Chow ◽  
C. L. Chien ◽  
A. S. Edelstein
Keyword(s):  
Particle Size ◽  
Thermal Gradient ◽  
Structural Evolution ◽  
Gas Pressure ◽  
Argon Gas ◽  
Size And Shape ◽  
Average Size ◽  
Sputtering Pressure

The evolution of the size and shape of molybdenum nanocrystals fabricated by sputtering in a thermal gradient has been studied as a function of the argon gas pressure, p. For 4 < p < 100 mTorr, continuous Mo films are deposited. At p = 150 mTorr, isolated and well-faceted Mo nanocrystals of two sizes (20 and 5 nm average size) are formed. For 200 ≤ p ≤ 400 mTorr, the particle size decreases with increasing pressure and is about 7 nm at 400 mTorr. On increasing p further, larger particles start to form and at p = 700 mTorr, particle agglomerates are observed. Possible mechanisms leading to these results are suggested.

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