A solid-state approach for the low temperature synthesis of Cr3Si hollow particles

2021 ◽  
Vol 112 (11) ◽  
pp. 918-921
Author(s):  
Liangbiao Wang ◽  
Zhe Chen ◽  
Yongjie Xie ◽  
Yuting Xiong ◽  
Qinglin Cheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Silicon Powder ◽  
Diffraction Field ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Low Temperature Synthesis ◽  
Hollow Particles ◽  
Transmission Electron ◽  
Metallic Lithium

Abstract In this paper, pure cubic chromium silicide (Cr3Si) hollow particles have been successfully synthesized through the solid-state reaction of chromium sesquioxide, silicon powder and metallic lithium in an autoclave at 600 °C for 10 h. The as-prepared samples were characterized by means of X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy, which showed that the as-prepared samples were cubic phase Cr3Si hollow particles. Furthermore, the oxidation resistance of the obtained Cr3Si sample was also investigated.

scholarly journals Synthesis and Characterization of Nano-Tungsten Oxide Precipitated onto Natural Inorganic Clay for Humidity-Sensing Applications

Ceramics ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 120-127 ◽  
Author(s):  
Ahmed Afify ◽  
Ahmed Elsayed ◽  
Mohamed Hassan ◽  
Mohamed Ataalla ◽  
Amr Mohamed ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Tungsten Oxide ◽  
Diffraction Field ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Applications ◽  
Transmission Electron ◽  
Tungsten Oxide Nanoparticles ◽  
Inorganic Clay

A wet chemical method was used to obtain tungsten oxide nanoparticles from tungsten tetrachloride and natural microfibrous inorganic clay (sepiolite) as a starting material. Precipitation of tungsten oxide species onto sepiolite under basic conditions and subsequent thermal treatment was investigated, prompted by the abundance of sepiolite in nature and the useful environmental applications that could be attained. Laser granulometry, X-ray diffraction, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), and high-resolution transmission electron microscopy (HR-TEM) techniques were used to study the particle-size distribution, the morphology, and the composition of the prepared sample. Our findings show the presence of tungsten oxide nanoparticles, which are less than 50 nm, on the needles of the modified sepiolite.

Synthesis and upconversion luminescence properties of CaF2:Yb3+,Er3+ nanoparticles obtained from SBA-15 template

2010 ◽  
Vol 25 (10) ◽  
pp. 2035-2041 ◽  
Author(s):  
Zhiguo Xia ◽  
Peng Du
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Emission Spectra ◽  
Average Diameter ◽  
Cubic Phase ◽  
Pumping Power ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Transmission Electron

CaF2:Yb3+,Er3+ upconversion (UC) luminescence nanoparticles have been synthesized using mesoporous silica (SBA-15) as a hard template. The samples were characterized by x-ray diffraction, Fourier transform infrared spectra, field-emission scanning electron microscopy, transmission electron microscopy, and UC emission spectra, respectively. Highly crystalline cubic phase CaF2:Yb3+,Er3+ nanoparticles are uniformly distributed with an average diameter of about 40–50 nm, and the formation process is also demonstrated. The UC fluorescence has been realized in the as-prepared CaF2:Yb3+,Er3+ nanoparticles on 980-nm excitation. The UC emission transitions for 4F9/2–4I15/2 (red), 2H11/2–4I15/2 (green), 4S3/2–4I15/2 (green), and 2H9/2–4I15/2 (violet) in the Yb3+/Er3+ codoped CaF2 nanoparticles depending on pumping power and temperature have been discussed. The UC mechanism, especially the origin on the temperature-dependent UC emission intensities ratio between 2H11/2 and 4S3/2 levels, have been proposed.

Preparation of PVC/Kaolin Nanocomposites through Solid State Shear Compounding Based on Pan-Milling

2011 ◽  
Vol 694 ◽  
pp. 350-354 ◽  
Author(s):  
Kan She Li ◽  
Ying Hong Chen ◽  
Hong Mei Niu ◽  
Jian Jun Chen
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Solid State ◽  
Impact Strength ◽  
Ambient Temperature ◽  
Mechanical Tests ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Filled Composite

Solid state shear compounding technology (S3C) based on pan-milling is an effective method to prepare polymer/layered mineral composites with nano intercalating structure. The PVC/Kaolin compounding powders were successfully prepared by pan-milling at ambient temperature, and then the PVC/Kaolin nanocomposites were processed by moulding The structure and properties of PVC/Kaolin compounding powder and nanocomposites were investigated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and mechanical tests. The results showed that the mechanical properties of PVC/Kaolin nanocomposites prepared through S3C based on pan-milling 30 cycles at ambient temperature including elongation, tensile strength and notched impact strength were remarkably improved compared with conventional filled composites. The elongation of PVC / Kaolin nanocomposites with 4 %wt. Kaolin was 274.6%, which is 187.3 % higher than that for a conventional filled composite. The tensile strength was 54.0 MPa, which is 6.3 MPa higher than that for a conventional filled composite. The tensile strength of the nanocomposites with 8 %wt. Kaolin was 57.5 MPa, which is 9.1 MPa higher than that for a conventional filled composite. At the same time, the notched impact strength was 4.9 kJ/m2, which is 1.0 kJ/m2 higher than a conventional filled composite. Strengthening and toughening for PVC were synchronously realized. XRD, SEM and TEM verified that S3C based on pan-milling realized synchronously pulverizing, dispersion and compounding of PVC with kaolin Through 25-30 cycles pan-milling, PVC and Kaolin powders imbedded each other and made into uniform PVC/Kaolin compounding powders and nanocomposites. The strip flake of Kaolin particles with thickness less than 50 nanometer and the aspect ratio of 10 times dispersed homogeneously in the PVC matrix.

Preparation, Characterization and Spectroscopy of Eu3+ in Gd2O3 Nanorods

2008 ◽  
Vol 8 (3) ◽  
pp. 1398-1403 ◽  
Author(s):  
Liqin Liu ◽  
En Ma ◽  
Renfu Li ◽  
Xueyuan Chen
Keyword(s):  
Electron Microscopy ◽  
Fluorescence Spectra ◽  
Filling Factor ◽  
Energy Levels ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Eu3+:Gd2O3 nanorods were prepared by a hydrothermal method. X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and Fourier transform-infrared spectroscopy were used to characterize the resulting samples. Emission and excitation spectra were studied using xenon excited spectroscopic experiments at 10 K. Energy transfer from Gd3+ to Eu3+, from the band gap of the host to Eu3+, and from Eu3+ (S6) to Eu3+ (C2) was observed. The energy levels of Eu3+ at the C2 site of cubic Gd2O3 were experimentally determined according to the fluorescence spectra at 10 K, and fit well with the theoretical values. The standard deviation for the optimal fit was 12.9 cm−1. The fluorescent lifetime of 5D0 (2.3 ms at 295 K) was unusually longer than that of the bulk counterparts (0.94 ms), indicating a small filling factor (0.55) for the nanorod volume. However the lifetime of 5D1 was much shorter than that of the bulk counterparts, 65 μs at 10 K, 37 μs at 295 K.

Luminescent properties of Y2O3:Eu3+ nanophosphor prepared from urea added precursor using flame spray pyrolysis

2009 ◽  
Vol 24 (8) ◽  
pp. 2584-2588 ◽  
Author(s):  
Jae Seok Lee ◽  
Se Jin Kim ◽  
Tae Kon Kim ◽  
Rajiv K. Singh ◽  
Madhav B. Ranade
Keyword(s):  
Electron Microscopy ◽  
Spray Pyrolysis ◽  
Red Light ◽  
Luminescent Properties ◽  
Flame Spray Pyrolysis ◽  
Cubic Phase ◽  
Flame Spray ◽  
X Ray Diffraction ◽  
Synthesis Conditions ◽  
Transmission Electron

Y2O3:Eu3+ nanophosphor was synthesized by flame spray pyrolysis (FSP) from urea added nitrate based liquid precursor. In this study, urea serves as fuel and subsequently provides additional heat in the flame zone during the synthesis of phosphor particles. The end product shows cubic phase Y2O3:Eu3+ nanophosphor successfully prepared by FSP without heat treatment. The influence of synthesis conditions such as different mol of urea and nitrate source materials in aqueous solution, and doping concentration on luminescent properties, were investigated. The characteristics of nanophosphor such as crystallinity and morphology under various experiments of conditions were carried out by x-ray diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM). The particle size of product was found to be in the range of 20–30 nm from transmission electron microscopy (TEM). In photoluminescence (PL) properties, Y2O3:Eu3+ nanophosphor emitted red light with a peak wavelength of 609 nm when excited with 398 nm wavelength photons.

Solvothermal Synthesis of CeO2 Nanoparticles

2011 ◽  
Vol 236-238 ◽  
pp. 2000-2003
Author(s):  
Yong Cai Zhang ◽  
En Ren Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Absorption Spectrum ◽  
Photoelectron Spectroscopy ◽  
Solvothermal Synthesis ◽  
Oxygen Vacancies ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Ultrafine CeO2 nanoparticles were synthesized directly via solvothermal treatment of Ce(NO3)3·6H2O powder in toluene at 180 °C for 48 h, and characterized by X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and UV-vis absorption spectrum. The results from XRD, Raman and XPS revealed the formation of pure cubic phase CeO2 with some oxygen vacancies. The TEM image disclosed that the as-synthesized CeO2 comprised nanoparticles of about 5–8 nm. The UV-vis absorption spectrum showed that the as-synthesized CeO2 nanoparticles had a wide UV absorption band centered at around 326 nm (3.8 eV).

SOLID STATE AMORPHIZATION IN MECHANICALLY ALLOYED Al–Ti–Si NANOCOMPOSITES

2005 ◽  
Vol 04 (05n06) ◽  
pp. 1025-1028
Author(s):  
I. MANNA ◽  
P. NANDI ◽  
B. BANDYOPADHYAY ◽  
P. M. G. NAMBISSAN ◽  
K. GHOSHRAY ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Amorphous Solid ◽  
Positron Annihilation Spectroscopy ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
X Ray ◽  
Transmission Electron ◽  
State Amorphization

The microstructural evolution at different stages of milling of a ternary powder blend of Al 50 Ti 40 Si 10 composition was monitored by X-ray diffraction, high-resolution transmission electron microscopy, positron annihilation spectroscopy and 27 Al nuclear magnetic resonance. Ball-milling leads to alloying, nanocrystallization and partial solid state amorphization, either followed or accompanied by strain-induced nucleation of nanocrystalline intermetallic phases from an amorphous solid solution.

Effects of Co content in TiO2–Co composite prepared by alloying–recomposition–oxidation–sintering process on its mechanical properties and microstructure

2019 ◽  
Vol 53 (24) ◽  
pp. 3483-3495
Author(s):  
Seungkyun Yim ◽  
Ilsong Park ◽  
Jeshin Park
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Diffraction Field ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
Transmission Electron ◽  
Content Range ◽  
Structural Characterizations

TiO2–Co composite powders with various Co contents were prepared by the alloying-recomposition-oxidation-sintering process. For comparison, conventionally mixed TiO2–Co composites with the same compositions were sintered at 1000, 1100, 1200, 1300, and 1400℃. Structural characterizations were performed using X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive spectroscopy, and transmission electron microscopy. All of the sintered samples were more densified. A melted matrix was observed at a temperature higher than 1300℃. The flexural strength and the fracture toughness of the TCA sample were higher than those of the conventionally mixed TiO2–Co sample at the same sintering temperature, while the Vickers hardness exhibited the opposite relationship. The flexural strength and the fracture toughness of the TCA sample increased until a Co content of 14 vol%, followed by decrease at 18 vol%, while those of the conventionally mixed TiO2–Co sample increased in the entire Co content range. The highest flexural strength and fracture toughness were observed for T14CA sintered at 1400℃ (161.3 MPa and 6.39 MPa m−1/2, respectively). Consequently, the desirable Co content in the TiO2–Co composite prepared by the alloying–recomposition–oxidation–sintering process was 14 vol%.

scholarly journals Mechanism of Nanostructured Fluorapatite Formation from CaO, CaF2 and P2O5 Precursors by Mechanochemical Synthesis

2018 ◽  
Vol 43 (3-4) ◽  
pp. 201-210
Author(s):  
Raheleh Nikonam Mofrad ◽  
Sayed Khatiboleslam Sadrnezhaad ◽  
Jalil Vahdati Khaki
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanochemical Synthesis ◽  
Diffraction Field ◽  
Ambient Atmosphere ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

We determined the mechanism of mechanochemical synthesis of fluorapatite from CaO, CaF2 and P2O5 by characterisation of the intermediate compounds. We used atomic absorption spectroscopy, X-ray diffraction, field emission scanning electron microscopy, FTIR spectroscopy and transmission electron microscopy to find the transitional compounds. Investigation of the binary and ternary powder mixtures revealed the appearance of H3PO4, Ca(OH)2, Ca2P2O7 and CaCO3 as the intermediate compounds. At early stages of the milling, conversions of P2O5 to H3PO4 and CaO to Ca(OH)2 occurred in the wet atmosphere. Later, a combination of Ca(OH)2 and H3PO4 formed C a2P2O7 while the unreacted CaO was converted to CaCO3 by CO2 of the ambient atmosphere. Spherical crystalline Ca10 (PO4)6F2 particles formed after 48 hours of milling due to the reaction between Ca2P2O7, CaCO3 and CaF2.

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