Reduction Behavior of W and Cu Oxides Powder Mixture

2008 ◽  
Vol 135 ◽  
pp. 143-149
Author(s):  
Seong Lee ◽  
Joon Woong Noh ◽  
Eun Pyo Kim ◽  
Moon Hee Hong
Keyword(s):  
Gas Phase ◽  
Powder Mixture ◽  
Hydrogen Atmosphere ◽  
Hydrogen Gas ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Composite Powders ◽  
Reduction Behavior ◽  
Scanning Electron Microscopic ◽  
Increasing Temperature

The reduction behavior of WO3 and CuO powder mixture has been studied by using thermo-gravimetric(TG), X-ray diffraction, and scanning electron microscopic analyses. The powder mixture was manufactured by ball-milling. It was found that W coated W-Cu composite powders were formed when reducing the powder mixture under hydrogen atmosphere. The following reduction steps are suggested as a mechanism for the formation of W coated W-Cu composite powders: with increasing temperature, Cu is initially reduced from CuO and the reduction reactions of WO3 to WO2 via WO2.9 and WO2.72 are followed. The gas phase WO2(OH)2 is formed by the reaction of the WO2 and water vapor, and then WO2(OH)2 diffuses toward Cu surface and deposits on it as W by reducing reaction with environmental hydrogen gas. The formation mechanism of W coated W-Cu composite powders involving the gas phase transportation reaction has been confirmed by the model experiment conducted by using Cu plate and WO3 powder.

scholarly journals Preparation of Reswellable Amorphous Porous Celluloses through Hydrogelation from Ionic Liquid Solutions

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3249 ◽  
Author(s):  
Satoshi Idenoue ◽  
Yoshitaka Oga ◽  
Daichi Hashimoto ◽  
Kazuya Yamamoto ◽  
Jun-ichi Kadokawa
Keyword(s):  
Mechanical Properties ◽  
Ionic Liquid ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Liquid Solutions ◽  
Scanning Electron Microscopic ◽  
Porous Morphology ◽  
Scanning Electron

In this study, we have performed the preparation of reswellable amorphous porous celluloses through regeneration from hydrogels. The cellulose hydrogels were first prepared from solutions with an ionic liquid, 1-butyl-3-methylimidazolium chloride (BMIMCl), in different concentrations. Lyophilization of the hydrogels efficiently produced the regenerated celluloses. The powder X-ray diffraction and scanning electron microscopic measurements of the products suggest an amorphous structure and porous morphology, respectively. Furthermore, the pore sizes of the regenerated celluloses, or in turn, the network sizes of cellulose chains in the hydrogels, were dependent on the concentrations of the initially prepared solutions with BMIMCl, which also affected the tensile mechanical properties. It was suggested that the dissolution states of the cellulose chains in the solutions were different, in accordance with the concentrations, which representatively dominated the pore and network sizes of the above materials. When the porous celluloses were immersed in water, reswelling was observed to regenerate the hydrogels.

Tribocorrosion behavior of electroless Ni-P/Ni-B duplex coating on AA7075 aluminum alloy

2019 ◽  
Vol 71 (5) ◽  
pp. 630-635 ◽  
Author(s):  
Harun Mindivan
Keyword(s):  
Aluminum Alloy ◽  
Surface Characterization ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Content Type ◽  
Duplex Coating ◽  
Scanning Electron Microscopic ◽  
Electroless Ni ◽  
Insight Into

Purpose This paper aims to investigate the structural, corrosion and the study of tribocorrosion features of the AA7075 aluminum alloy with and without the application of electroless Ni-P/Ni-B duplex coating with a thickness of approximately 40 microns. Design/methodology/approach Surface characterization of the samples was made by structural surveys (light optic microscope, scanning electron microscopic examinations and X-ray diffraction analyses), hardness measurements, corrosion and tribocorrosion tests. Findings Results of the experiments showed that upper Ni-B coating deposited on the surface of first Ni-P layer by duplex treatment caused remarkable increment in the hardness, corrosion resistance and tribocorrosion performance as compared to the AA7075 aluminum alloy. Originality/value This study can be a practical reference and offers insight into the effects of duplex treating on the increase of hardness, corrosion and tribocorrosion performance.

scholarly journals Influence of the type of electrolyte on the morphological and crystallographic characteristics of lead powder particles

2013 ◽  
Vol 78 (9) ◽  
pp. 1387-1395 ◽  
Author(s):  
Nebojsa Nikolic ◽  
Vesna Maksimovic ◽  
Goran Brankovic ◽  
Predrag Zivkovic ◽  
Miomir Pavlovic
Keyword(s):  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Lead Powder ◽  
Scanning Electron Microscopic ◽  
Crystallographic Characteristics ◽  
Powder Particles ◽  
Primary Type ◽  
Secondary Type ◽  
Scanning Electron

Lead electrodeposition processes from the basic (nitrate) and complex (acetate) electrolytes were mutually compared by the scanning electron microscopic and the X-ray diffraction analysis of the produced powder particles. The shape of dendritic particles strongly depended on the type of electrolyte. The dendrites composed of stalk and weakly developed primary branches (the primary type) were predominantly formed from the basic electrolyte. The ramified dendrites composed of stalk and of both primary and secondary branches (the secondary type) were mainly formed from the complex electrolyte. In the both type of powder particles Pb crystallites were predominantly oriented in the (111) plane. Formation of powder particles of the different shape with the strong (111) preferred orientation was discussed and explained by the consideration of the general characteristics of the growth of a crystal in the electrocrystallization processes.

Optimization of Calcium Carbonate Precipitation for Bacillus pasteurii

2012 ◽  
Vol 178-181 ◽  
pp. 676-679 ◽  
Author(s):  
Tao Duan ◽  
Wen Kun Zhu
Keyword(s):  
Calcium Carbonate ◽  
Crystal Formation ◽  
Carbonate Precipitation ◽  
X Ray Diffraction ◽  
Calcium Carbonate Precipitation ◽  
Electron Microscopic ◽  
Bacillus Pasteurii ◽  
Scanning Electron Microscopic ◽  
External Conditions ◽  
Effects Of Temperature

The effects of temperature, pH, precipitation time, reactant concentration, the crystal formation additive on the yield of calcium carbonate precipitation induced by bacillus pasteurii were investigated through orthogonal test. The morphology and structure of the calcium carbonate were characterized by scanning electron microscopic (SEM), Fourier transform infrared spectroscopy (IR) and powder X-ray diffraction (XRD). The results showed that the optimum conditions of calcium carbonate precipitation induced by bacillus pasteurii were temperature of 40oC, pH of 8, precipitation time of 3 d, Ca2+ of 1.5 mol/L, and Mg2+ of 0.05 mol/L. The crystal of calcium carbonate was calcites or mixture of calcites and vaterite. Its morphology and packing density were changed by different external conditions.

Nanocomposites Based on High-Tc Superconducting Ceramic 2212 BSCCO and their Properties

2014 ◽  
Vol 938 ◽  
pp. 210-214
Author(s):  
T.K. Jayasree ◽  
P. Predeep
Keyword(s):  
Sol Gel ◽  
Microscopic Investigation ◽  
Electron Microscopic Investigation ◽  
X Ray Diffraction ◽  
Polymer Phase ◽  
Electron Microscopic ◽  
Scanning Electron Microscopic ◽  
Scanning Electron Micrography ◽  
Superconducting Ceramic ◽  
Scanning Electron

High temperature superconducting (SC) 2212 BiSrCaCuO nanoparticles were prepared by Sol-Gel method. Precursor was characterized by X-ray diffraction (XRD) and scanning Electron micrography. The superconductor nanocomposites were fabricated by nanoparticles of the SC powder with NR/LLDPE blends. The superconductive properties of the sintered samples and the nanocomposites were studied. Transition to a superconducting state around 88K appeared in the parent sample and in the composites. The scanning electron microscopic investigation of the nanostructures of SC polymer ceramic nanocomposites shown nanoscale dispersion of BSCCO in the polymer phase uniformly.

Characterization on Aggregating Structure of Aloe Extract Crosslinked Cotton Fabric

2011 ◽  
Vol 311-313 ◽  
pp. 1132-1135 ◽  
Author(s):  
Yun Hui Xu ◽  
Li Chen
Keyword(s):  
Citric Acid ◽  
Cotton Fabric ◽  
Cotton Textile ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Scanning Electron Microscopic ◽  
Ft Ir ◽  
Textile Products

For exploiting the multifunctional ecological cotton textile products and developing the green modified technology for cotton fabrics, a novel cotton fabric with aloe extract crosslinking was prepared using citric acid as a crosslink agent under the pad-dry-cure procedure. Scanning electron microscopic photographs showed that the modification with aloe extract occurred on the surface of cotton fabric. FT-IR spectra of the modified fabric illuminated that aloe extract crosslinked with cotton fabric through the bridge linkage of citric acid after a series of reaction. The wide angle X-ray diffraction analysis indicated that the crystallinity of aloe extract modified cotton fabric slightly decreased. Furthermore, the changes in the aggregating structure and crystallinity were also reflected in the mechanical property studies of these modified fabrics. After treatment by aloe extract, the breaking strength and elongation of cotton fabric decreased. However, the moisture regain of the modified cotton fabric increased. The results obtained are useful in explaining structure-property correlations with respect to the aggregating structure and crystallinity, and suggest valuable information in planning applications for the aloe extract modified cotton textile products.

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