scholarly journals Preparation and Characterization of Magnesia-based Powder Added With Transition Metal

2020 ◽  
Author(s):  
Bong-Gu Kim ◽  
Hyun-Hee Choi ◽  
Jung-Hun Son ◽  
SeungCheol Yang ◽  
Min-Seok Kwon ◽  
...  
Keyword(s):  
Particle Size ◽  
Reaction Time ◽  
Solid Phase ◽  
Processing Parameters ◽  
High Reactivity ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Binary Composition ◽  
Substitutional Element ◽  
Particle Characteristics

Abstract The solid-phase reaction method for preparing forsterite (Mg2SiO4) using MgO and SiO2 powders has the disadvantages of high reaction temperature, long reaction time, and inhomogeneous reaction depending on the particle size of MgO. Therefore, MgO-based powders with a high reactivity were synthesized using a coprecipitation method with substitutional elements (Mn or Ni), and the effects of processing parameters on synthesizing MgO-based binary composition powders were investigated through the particle characteristics. The crystal structure continuously changed with the contents of the substitutional element, showing the same trend as the atomistic simulation results. The MgO-based powders showed higher reactivity than the conventional MgO powder, which could be confirmed in the particle characteristics, such as particle size and crystallinity, obtained in a short reaction time, and at a relatively low temperature. The optimum composition ratio in the binary composition powder for forming the Mg2SiO4 depended on the type of substitutional element, and the reaction mechanism was identified based on the particle characteristics.

scholarly journals Scintillation materials based on solid solutions ZnSxSe1–x

2018 ◽  
pp. 43-49
Author(s):  
O. G. Trubaieva ◽  
M. A. Chaika ◽  
S. M. Galkin ◽  
A. I. Lalayants ◽  
T. A. Nepokupnaya
Keyword(s):  
Particle Size ◽  
Solid Solutions ◽  
Solid Phase ◽  
Short Wave ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
X Ray ◽  
Al Composite ◽  
Wave Region ◽  
Short Wave Region

Composite materials based on ZnSxSe1–x solid solutions are promising materials for gamma and X-ray detectors. However, influence of compositions and particle size on scintillation properties is unclear, which prevents their application. This paper reports on the complex study of microcrystalline ZnSxSe1–x powdered scintillations, prepared by solid phase synthesis from ZnS and ZnSe initial compounds. ZnSxSe1-x solid solutions were obtained in the range of x from 0.07 to 0.86 and in the following sizes: 200—250, 140—200, 140—80 µm, and less than 80 µm. X-ray diffractions of powder ZnSxSe1–x shows formation of a cubic lattice of sphalerite structure. ZnSxSe1–x powders demonstrate a presence of a luminescence band in the 590—615 nm regions, while an increase in sulfur concentration leads to a shift of the maximum intensity of X-ray induced luminescence to the short-wave region, which is associated with an increase of the band gap width. The best parameters of X-ray induced luminescence are obtained for the solid solution with 39 at.% of sulfur. The ZnS0,39Se0,61 solid solutions obtained under these conditions have an X-ray induced luminescence intensity that is 4 times higher than that of ZnSe(Al) single crystal and a relatively low level of afterglow. In ZnSxSe1–x solid solutions, increasing of particle size leads to shifts of the X-ray induced luminescence to the longwave region. The highest intensity of the X-ray induced luminescence corresponds to the ZnS0,39Se0,61 composition with the particle size of less than 80 µm. Also, ZnS0,39Se0,61 solid solutions, with particle size less than 80 microns, are more homogeneous in composition, which is why the process of solid phase reaction in them passes more efficiently. It is shown that the ZnSxSe1-x composite scintillators can be used as gamma and X-ray detectors. It has been established that the effectiveness of these materials depends on their composition. ZnS0,5Se0,5 and ZnS0,39Se0,61 composites demonstrate the best scintillation characteristics, with twice as high an efficiency as that of the «commercial» ZnSe(Al) composite.

scholarly journals Fe3O4@C Nanoparticles Synthesized by In Situ Solid-Phase Method for Removal of Methylene Blue

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 330
Author(s):  
Hengli Xiang ◽  
Genkuan Ren ◽  
Yanjun Zhong ◽  
Dehua Xu ◽  
Zhiye Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Solid Phase ◽  
Raw Materials ◽  
Phase Method ◽  
Maximum Adsorption Capacity ◽  
High Catalytic Activity ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
High Concentrations

Fe3O4@C nanoparticles were prepared by an in situ, solid-phase reaction, without any precursor, using FeSO4, FeS2, and PVP K30 as raw materials. The nanoparticles were utilized to decolorize high concentrations methylene blue (MB). The results indicated that the maximum adsorption capacity of the Fe3O4@C nanoparticles was 18.52 mg/g, and that the adsorption process was exothermic. Additionally, by employing H2O2 as the initiator of a Fenton-like reaction, the removal efficiency of 100 mg/L MB reached ~99% with Fe3O4@C nanoparticles, while that of MB was only ~34% using pure Fe3O4 nanoparticles. The mechanism of H2O2 activated on the Fe3O4@C nanoparticles and the possible degradation pathways of MB are discussed. The Fe3O4@C nanoparticles retained high catalytic activity after five usage cycles. This work describes a facile method for producing Fe3O4@C nanoparticles with excellent catalytic reactivity, and therefore, represents a promising approach for the industrial production of Fe3O4@C nanoparticles for the treatment of high concentrations of dyes in wastewater.

Microstructure and Mechanical Properties of ZrB2/h-BN Multiphase Ceramics by Low-Temperature Reactive Sintering

2016 ◽  
Vol 697 ◽  
pp. 510-514 ◽  
Author(s):  
Feng Rui Zhai ◽  
Ke Shan ◽  
Ruo Meng Xu ◽  
Min Lu ◽  
Zhong Zhou Yi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Relative Density ◽  
Fracture Strength ◽  
Solid Phase ◽  
Raw Materials ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Microstructure And Mechanical Properties ◽  
Multiphase Ceramics ◽  
Strength And Toughness

In the present paper, the ZrB2/h-BN multiphase ceramics were fabricated by SPS (spark plasma sintering) technology at lower sintering temperature using h-BN, ZrO2, AlN and Si as raw materials and B2O3 as a sintering aid. The phase constitution and microstructure of specimens were analyzed by XRD and SEM. Moreover, the effects of different sintering pressures on the densification, microstructure and mechanical properties of ZrB2/h-BN multiphase ceramics were also systematically investigated. The results show that the ZrB2 was obtained through solid phase reaction at different sintering pressures, and increasing sintering pressure could accelerate the formation of ZrB2 phase. As the sintering pressure increasing, the fracture strength and toughness of the sintered samples had a similar increasing tendency as the relative density. The better comprehensive properties were obtained at given sintering pressure of 50MPa, and the relative density, fracture strength and toughness reached about 93.4%, 321MPa and 3.3MPa·m1/2, respectively. The SEM analysis shows that the h-BN grains were fine and uniform, and the effect of sintering pressure on grain size was inconspicuous. The distribution of grain is random cross array, and the fracture texture was more obvious with the increase of sintering pressure. The fracture mode of sintered samples remained intergranular fracture mechanism as sintering pressure changed, and the grain refinement, grain pullout and crack deflection helped to increase the mechanical properties.

Study of solid-phase reaction between CsNO3 AND V2O5 in the molar ratio 6:5

1980 ◽  
Vol 18 (3) ◽  
pp. 469-476 ◽  
Author(s):  
Ľ. Žúrková ◽  
K. Gáplovská ◽  
V. Suchá
Keyword(s):  
Solid Phase ◽  
Molar Ratio ◽  
Solid Phase Reaction ◽  
Phase Reaction

X-Ray and Magnetic Measurements of TmFeTi2O7

2014 ◽  
Vol 215 ◽  
pp. 470-473 ◽  
Author(s):  
Tamara V. Drokina ◽  
German A. Petrakovskii ◽  
Dmitrii A. Velikanov ◽  
Maksim S. Molokeev
Keyword(s):  
Spin Glass ◽  
Solid Phase ◽  
Magnetic Measurements ◽  
Diffraction Method ◽  
Freezing Temperature ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
History Of

In this paper we are reported about a peculiarity of the crystal structure and the magnetic state of TmFeTi2O7. The compound TmFeTi2O7 has been synthesizedusing the solid-phase reaction method. Using X-ray diffraction method the disorder in the distribution of the iron ions over five nonequivalent crystal sites was observed, also the populations of the iron atoms positions were determined. We show that below Tf = 6 K the magnetization of TmFeTi2O7 depends on the magnetic history of the sample. There are indications for spin glass state. This results allow us to assume the state of spin glass is realized below freezing temperature Tf = 6 K in TmFeTi2O7.

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