Intrinsic reduction kinetics of cobalt- and nickel-titanates by hydrogen

2000 ◽  
Vol 15 (2) ◽  
pp. 338-346 ◽  
Author(s):  
I. Arvanitidis ◽  
A. Kapilashrami ◽  
Du Sichen ◽  
S. Seetharaman
Keyword(s):  
Electron Microscopy ◽  
Activation Energy ◽  
Hydrogen Reduction ◽  
High Flow ◽  
Reduction Kinetics ◽  
Isothermal Reduction ◽  
Analysis Technique ◽  
Kinetics Of ◽  
Scanning Electron ◽  
Cobalt And Nickel

The isothermal reduction of synthetic CoTiO3 and NiTiO3 in hydrogen (1 atm) was investigated using thermogravimetric analysis technique in the temperature range, 928–1287 K (CoTiO3) and 884–1387 K (NiTiO3). Shallow beds of fine titanate powders were reduced by hydrogen at a high flow rate. Quenched samples were analyzed by scanning electron microscopy. The rates of the reaction of the titanates with H2 were very fast during the reduction of Co2+, Ni2+, or Fe2+ ions into metals. The reduction of the remaining titanium oxide was very slow. The activation energy for the reduction of CoTiO3 by hydrogen to Co and TiO2 was evaluated to be 151 ± 1 kJ/mol, and the activation energy for the reduction of NiTiO3 by hydrogen to Ni and TiO2 was evaluated to be 153 ± 1 kJ/mol. The study was complemented by hydrogen reduction of synthetic TiO2 (rutile). The results were also compared with the hydrogen reduction of FeTiO3.

Anisotropic Membranes as Substrates for Sem

1976 ◽  
Vol 34 ◽  
pp. 444-445
Author(s):  
Thomas P. Turnbull ◽  
W. F. Bowers
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Flow ◽  
Polymer Chemistry ◽  
Surface Porosity ◽  
Transmission Electron ◽  
Pore Texture ◽  
Spongy Layer ◽  
Scanning Electron

Until recently the prime purposes of filters have been to produce clear filtrates or to collect particles from solution and then remove the filter medium and examine the particles by transmission electron microscopy. These filters have not had the best characteristics for scanning electron microscopy due to the size of the pores or the surface topography. Advances in polymer chemistry and membrane technology resulted in membranes whose characteristics make them versatile substrates for many scanning electron microscope applications. These polysulphone type membranes are anisotropic, consisting of a very thin (0.1 to 1.5 μm) dense skin of extremely fine, controlled pore texture upon a much thicker (50 to 250μm), spongy layer of the same polymer. Apparent pore diameters can be controlled in the range of 10 to 40 A. The high flow ultrafilters which we are describing have a surface porosity in the range of 15 to 25 angstrom units (0.0015-0.0025μm).

scholarly journals Preparation and Assessment of Some Characteristics of Nanoparticles Based on Sodium Alginate, Chitosan, and Camellia chrysantha Polyphenols

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Phu Hoang Luong ◽  
Thuy Chinh Nguyen ◽  
The Dan Pham ◽  
Do Mai Trang Tran ◽  
Thi Ngoc Lien Ly ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Release Kinetics ◽  
Release Kinetic ◽  
Ionic Gelation ◽  
Visible Spectroscopy ◽  
Polyphenol Content ◽  
Release Process ◽  
Kinetics Of ◽  
Scanning Electron

This paper presents the characteristics, morphology, and properties of alginate/chitosan/polyphenol nanoparticles, in which polyphenols were extracted from Camellia chrysantha leaves collected in Tam Dao district, Vinh Phuc province (Vietnam). The alginate/chitosan/polyphenol nanoparticles were prepared by ionic gelation method at different polyphenol content. The characteristics and morphology of these nanoparticles were investigated using infrared spectroscopy (IR), ultraviolet-visible spectroscopy (UV-Vis), and scanning electron microscopy (SEM). Release kinetic of polyphenols from the alginate/chitosan/polyphenol nanoparticles was conducted in simulated human body fluids. The release kinetics of polyphenols from the above nanoparticles were also evaluated and discussed. The experimental results showed that the release process of polyphenols from the nanoparticles was dependent on three factors: time, pH of solution, and amount of polyphenols.

scholarly journals Структура и механизмы образования наноразмерных пленок примесного металла кобальта и никеля в монокристаллах LiF и MgF-=SUB=-2-=/SUB=-

2021 ◽  
Vol 63 (9) ◽  
pp. 1340
Author(s):  
Н.А. Иванов ◽  
С.А. Небогин ◽  
С.С. Колесников ◽  
Л.И. Брюквина
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Etch Pits ◽  
Force Microscopy ◽  
Thermal Etching ◽  
Air Atmosphere ◽  
Atomic Force ◽  
Residual Air ◽  
Scanning Electron ◽  
Cobalt And Nickel

It is investigated the thermal etching of LiF and MgF2 crystals with cobalt and nickel impurities by means of scanning electron microscopy and atomic force microscopy with using decorating. It is shown that impurity inclusions leave the crystal from dislocations. The differences between of thermal etching in vacuum and air atmosphere take place. The crystallographic oriented terraced etch pits are formed after exit of impurities from dislocations. The square thermal etch pits are formed after thermal etching at 750°C in air. The surface impurity nanoscale film is formed at thermal etching. The oxidation of surface impurities observed at thermal etching in air atmosphere or in residual air atmosphere.

Isothermal Reduction Kinetics of Titanium Dioxide-Based Materials

1997 ◽  
Vol 101 (7) ◽  
pp. 1113-1124 ◽  
Author(s):  
James E. Rekoske ◽  
Mark A. Barteau
Keyword(s):  
Titanium Dioxide ◽  
Reduction Kinetics ◽  
Isothermal Reduction ◽  
Kinetics Of

scholarly journals Curing kinetics of phenolphthalein based polyphosphazene towards thermal stability and flame retardancy of polybenzoxazine

RSC Advances ◽  
2019 ◽  
Vol 9 (54) ◽  
pp. 31583-31593 ◽  
Author(s):  
Ling Zhao ◽  
Chunxia Zhao ◽  
Min Wu ◽  
Yuntao Li ◽  
Hui Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Flame Retardancy ◽  
Curing Kinetics ◽  
Ultrasound Assisted ◽  
Kinetics Of ◽  
Polymerization Method ◽  
Scanning Electron

Phenolphthalein type polyphosphazene (PZPT) microspheres were synthesized by an ultrasound assisted precipitation polymerization method, and their structures were confirmed by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy.

Isothermal Reduction Kinetics of Chromium-Bearing Vanadium–Titanium Sinter Reduced with CO Gas at 1173 K

JOM ◽  
2019 ◽  
Vol 71 (8) ◽  
pp. 2812-2820 ◽  
Author(s):  
Songtao Yang ◽  
Mi Zhou ◽  
Xiangxin Xue ◽  
Tao Jiang ◽  
Changyu Sun
Keyword(s):  
Reduction Kinetics ◽  
Isothermal Reduction ◽  
Vanadium Titanium ◽  
Kinetics Of ◽  
Co Gas

Thermal Decomposition Kinetics of Ammonium Aluminum Carbonate Hydroxide

2008 ◽  
Vol 368-372 ◽  
pp. 1577-1579
Author(s):  
Hai Jun Zhang ◽  
En Xia Xiu ◽  
Xiu Juan Wang ◽  
Quan Li Jia ◽  
Hong Wei Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Preexponential Factor ◽  
Decomposition Kinetics ◽  
Algebraic Expression ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbonate Hydroxide ◽  
Kinetics Of ◽  
Scanning Electron

The thermal decomposition of ammonium aluminum carbonate hydroxide was studied under non-isothermal conditions in air. The decomposition kinetics were evaluated from data of TG-DTA by means of the Kissinger equation and the Coats-Redfern equation. The values of the activation energy E, the preexponential factor A and the algebraic expression of integral G(α) functions of the thermal decomposition were calculated. The ammonium aluminum carbonate hydroxide (AACH) was characterized by X-ray diffraction, differential thermal analysis and thermogravimetric and field emission scanning electron microscopy.

Structural and electrical investigation of (Ag3AsS3)x(As2S3)1−x superionic glasses

Open Physics ◽  
2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Ihor Studenyak ◽  
Yuriy Neimet ◽  
Csaba Cserháti ◽  
Sándor Kökényesi ◽  
Edvardas Kazakevičius ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Activation Energy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Transmission Coefficient ◽  
Structural Studies ◽  
Compositional Range ◽  
Electrical Investigation ◽  
Scanning Electron

AbstractStructural studies of (Ag3AsS3)x (As2S3)1−x chalcogenide superionic glasses in the compositional range x = 0.3–0.9 were performed by scanning electron microscopy. Temperature and compositional dependences of transmission coefficient, electrical conductivity, and activation energy were investigated

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