Carbothermal reduction of low-grade pyrolusite by microwave heating

RSC Advances ◽  
2014 ◽  
Vol 4 (102) ◽  
pp. 58164-58170 ◽  
Author(s):  
Qianxu Ye ◽  
Hongbo Zhu ◽  
Libo Zhang ◽  
Peng Liu ◽  
Guo Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Crystal Structures ◽  
Microwave Heating ◽  
Energy Dispersive Spectroscopy ◽  
Carbothermal Reduction ◽  
Low Grade ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Pyrolusite was carbothermally reduced using coal by microwave heating, and the crystal structures and microstructures of the samples were characterized after microwave heating using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS).

Biomorphic SiC Prepared from Carbonized Millet by Sol-Gel and Carbothermal Reduction Processing

2010 ◽  
Vol 152-153 ◽  
pp. 1683-1686
Author(s):  
Qing Wang ◽  
Ya Hui Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silicon Carbide ◽  
Phase Composition ◽  
Carbothermal Reduction ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Template ◽  
Scanning Electron

Biomorphic silicon carbide (bioSiC) was prepared by high temperature pyrolysis and sol-gel and carbothermal reduction processing at 1600 oC. The morphology and microstructure of carbon-silica composites and purified bioSiC samples were characterized by scanning electron microscopy. The phase composition of the resulting sample was analyzed by X-ray diffraction. The results suggest that the bioSiC mainly consists of cubic ß-SiC, and principally replicates the shape and microstructure of the carbon template.

Preparation of Pd /α–Al2O3 and Pd-Ag/α–Al2O3 Membranes by Electroless Plating and Permeation Measurements

2012 ◽  
Vol 1372 ◽  
Author(s):  
L. Ortiz-Martínez ◽  
M. Torres-Rodríguez ◽  
M. Gutiérrez-Arzaluz
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electroless Plating ◽  
Energy Dispersive Spectroscopy ◽  
Ceramic Composite ◽  
Composite Membranes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Α Al2o3 ◽  
Scanning Electron

ABSTRACTIn this work, the synthesis of dense Pd/α–Al2O3 and Pd-Ag/α–Al2O3 ceramic composite membranes was done through the sequential electroless plating technique of Pd and Ag. The precursors are solutions of PdCl2 and AgNO3 and N2H4 salts, as reducing agent. The membranes were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). The permeation tests of H2 and N2 was carried out at 20 psi of pressure and at 25°C, resulted πH2=5.2x10-9 mol H2/m2·s·Pa and πN2=8.2x10-10 mol N2/m2·s·Pa.

scholarly journals Microstructure of Dental Amalgams Containing High and Low Copper Contents

1977 ◽  
Vol 56 (12) ◽  
pp. 1481-1487 ◽  
Author(s):  
Manohar L. Malhotra ◽  
Kamal Asgar
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
20Th Century ◽  
Energy Dispersive Spectroscopy ◽  
Optical Metallography ◽  
Dental Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dental Amalgams ◽  
Scanning Electron

Microstructure of commercial dental alloys and their amalgams were studied primarily by x-ray diffraction, optical metallography, scanning electron microscopy, and x-ray energy dispersive spectroscopy. X-ray diffraction revealed more phases than normally reported in these materials. Presence of new phases was discussed and their formation mechanism understood. Some phases having interacting 2θ° values with others were properly identified. Both new and conventional dental alloys and their amalgams, namely Tytin, Sybraloy, Dispersalloy, Kerr Spheraloy, Caulk Spherical, Shofu Spherical, and Caulk 20th Century Microcut were used to complete the investigation.

Carbothermal Synthesis of Cr3C2-WC-Ni Nanocomposite Powders

2013 ◽  
Vol 661 ◽  
pp. 3-6 ◽  
Author(s):  
Yong Zhong Jin ◽  
Fa Ming Ye ◽  
Xian Guang Zeng ◽  
Rui Song Yang
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Carbothermal Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbothermal Synthesis ◽  
Unit Cells ◽  
Nanocomposite Powders ◽  
Scanning Electron

Cr3C2-WC-Ni nanocomposite powders with ~50-100 nm were synthesized from precursors by vacuum-aided carbothermal reduction at only 750 °C for 2 h. The phase composition and microstructure of the synthesized products were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The present study shows that Cr3C2-WC-Ni nanocomposite powders contain two kinds of solid-solution phases, namely Ni and (Cr, W)3C2solid solution, respectively. WC and W2C phases do not appear inreaction products due to the dissolution of tungsten atoms into Ni and Cr3C2unit cells. Especially, there is a change of the crystalline structure for (Cr, W)3C2phase from 750 °C to 800 °C.

Study on the Mechanism of Magnesium Sulfate to Cement and C-S-H Gel

2011 ◽  
Vol 243-249 ◽  
pp. 4687-4690 ◽  
Author(s):  
Xiu Juan Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Magnesium Sulfate ◽  
Energy Dispersive Spectroscopy ◽  
Concrete Strength ◽  
Energy Dispersive ◽  
Test Block ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

The microstructure of cement test block and the C-S-H gel attacked by magnesium sulfate is observed by means of scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD).It is found that the presence of Mg2+ makes C-S-H gel decalcify, dissolve and decompose, which thereby increasing the erosion of SO42- on the concrete. The decomposition of C-S-H and the generation of M-S-H result in the loss of concrete strength and the ultimate destruction of concrete.

scholarly journals Approach to the knowledge of preservation of pleistocenic bone: The case of a Gomphothere cranium from the site of Tepeticpac, Tlaxcala, Mexico

2019 ◽  
Vol 36 (2) ◽  
pp. 170-182
Author(s):  
Luisa Straulino ◽  
Luisa Mainou ◽  
Teresa Pi ◽  
Sergey Sedov ◽  
Aurelio López-Corral ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive Spectroscopy ◽  
Crystallinity Index ◽  
X Ray Diffraction ◽  
Volcanic Origin ◽  
X Ray ◽  
Cell Parameters ◽  
Scanning Electron ◽  
Microbial Attack

An almost complete cranium of a gomphoterium found in Tepeticpac, Tlaxcala, was analyzed with X-ray diffraction (XRD), Petrography and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS) to stablish the transformations of the bone during its burial. The analyses assessed that the bone mineral (bioapatite) had suffered modifications in mineral composition, “crystallinity index”, cell parameters and CO2 content. However, the paleohistological structure of the bone was not significantly affected, although evidence of microbial attack was found in the bone surfaces. The filling minerals of bone macro and micro porosity were also analyzed; its main filling minerals are calcite (micrite and sparite), clays, and minerals of volcanic origin.

Nanostructured Morphology of Spinel LiMn2O4 Oxide under Microwave Heating

2014 ◽  
Vol 936 ◽  
pp. 452-458
Author(s):  
Di Huo
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Morphology ◽  
Microwave Heating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Morphology And Structure ◽  
Scanning Electron

The surface morphology and structure of the cubic stoichiometric spinel LiMn2O4powder prepared by microwave heating were examined using X-ray diffraction, scanning electron microscopy and transmittance electron microcopy. It is shown that the surface morphology of LiMn2O4particle changed with increasing preparing temperature, while the crystal structure kept unchanged. Novel nanostructured morphologies including nanorods and nanowhiskers were formed under appropriate synthesis conditions. The growth mechanism of the nanostructured morphology of spinel LiMn2O4was discussed in accordance with period bonding chains (PBCs) theory.

scholarly journals Preparation of biomorphic SiC ceramics

2008 ◽  
Vol 40 (2) ◽  
pp. 141-145 ◽  
Author(s):  
A. Egelja ◽  
J. Gulicovski ◽  
A. Devecerski ◽  
M. Ninic ◽  
A. Radosavljevic-Mihajlovic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Carbothermal Reduction ◽  
Oxide Ceramic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Preform ◽  
Sic Ceramics ◽  
Porous Sic ◽  
Scanning Electron

This paper deals with a new method for producing non-oxide ceramic using wood as a template. SiC with a woodlike microstructure has been prepared by carbothermal reduction reactions of Tilia wood/TEOS composite at 1873K. The porous carbon preform was infiltrated with TEOS (Si(OC2H5)4), as a source of silica, without pressure at 298K. The morphology of resulting porous SiC ceramics, as well as the conversion mechanism of wood to SiC ceramics, have been investigated by scanning electron microscopy (SEM/EDS) and X-ray diffraction analysis (XRD). Obtained SiC ceramics consists of ?-SiC with traces of ?-SiC.

ELECTROLESS DEPOSITION OF Ni-P ALLOYS ON CENOSPHERES BY USING SILVER AS THE CATALYST

2006 ◽  
Vol 20 (12) ◽  
pp. 715-723
Author(s):  
JIAN XU ◽  
WEIHAO XIONG ◽  
AIXIANG ZENG
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive Spectroscopy ◽  
Electroless Deposition ◽  
Coating Process ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Electroless Ni ◽  
Scanning Electron

Electroless deposition of Ni-P alloys on cenospheres is demonstrated in the present investigation. AgNO 3 is used as an activator to replace the conventional PdCl 2 activator and [Formula: see text] in the coating bath is used as the reducing agent to replace Sn 2+ in order to lower the overall cost of the coating process. The coated cenospheres are characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and powder X-ray diffraction (XRD). It shows that Ni-P alloys uniformly deposit on the surface of the cenospheres under experimental conditions. The possible mechanism of electroless Ni-P alloys coating of cenospheres by using silver as the catalyst is suggested.

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