Kinetic analysis of thermal decomposition reactions. VII. Effect of radiation and doping on the thermal decomposition of BaCO3–TiO2 and SrCO3–TiO2 crystalline mixtures

1992 ◽  
Vol 70 (3) ◽  
pp. 888-893 ◽  
Author(s):  
Suliman N. Basahel ◽  
El-Hussieny M. Diefallah
Keyword(s):  
Thermal Decomposition ◽  
Titanium Dioxide ◽  
Solid State ◽  
Kinetic Analysis ◽  
Solid State Reaction ◽  
Strontium Carbonate ◽  
Irradiation Effects ◽  
Γ Irradiation ◽  
Decomposition Reactions ◽  
Reaction Models

DTA–TG techniques were applied to study the thermal decomposition and reactivity in intimately mixed powders of barium or strontium carbonate and titanium dioxide. The results showed that the temperature for the thermal decomposition of BaCO3–TiO2 mixtures precedes the decomposition of pure BaCO3 by about 250 °C, whereas the decomposition of SrCO3–TiO2 mixtures precedes the decomposition of pure SrCO3 by about 60 °C. Kinetic analysis of the isothermal data in view of various solid-state reaction models showed that the reaction is best described by the phase boundary models. The effects of 60Co γ irradiation and of doping the metal oxide with Li+ or Cu2+ ions on the thermal decomposition reactions were investigated. Keywords: titanates, thermal decomposition, doping, irradiation effects.

Kinetic Analysis of One-Step Solid-State Reaction for Li4Ti5O12/C

2011 ◽  
Vol 115 (46) ◽  
pp. 13413-13419 ◽  
Author(s):  
Xuebu Hu ◽  
Ziji Lin ◽  
Kerun Yang ◽  
Zhenghua Deng
Keyword(s):  
Solid State ◽  
Kinetic Analysis ◽  
Solid State Reaction ◽  
One Step

scholarly journals Synthesis of Cubic Phase-Co Microspheres by Mechanical Solid-State Reaction-Thermal Decomposition and Research on Its Growth Kinetics

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Ying Deng ◽  
Yanhua Zhang ◽  
Lingling Peng ◽  
Xiaolong Jing ◽  
Hui Chen
Keyword(s):  
Thermal Decomposition ◽  
Solid State ◽  
Grain Growth ◽  
Solid State Reaction ◽  
Room Temperature ◽  
Energy Content ◽  
Industrial Applications ◽  
Cubic Phase ◽  
Oxalate Precursor ◽  
Cobalt Oxalate

Cubic phase cobalt (Co), which can be used as a key component for composite materials given its excellent ductility and internal structure, is not easy to obtain at room temperature. In this study, oxalic acid and cobalt nitrate are used as raw materials to synthesize the cobalt oxalate precursor, which has a stable structure with a five-membered chelate ring. Cobalt oxalate microspheres, having a high internal energy content, were prepared by using mechanical solid-state reaction in the presence of a surfactant, which can produce spherical micelles. The thermal decomposition of the precursor was carried out by maintaining it in a nitrogen atmosphere at 450°C for 3 h. At the end of the procedure, 100 nm cubic phase-Co microspheres, stable at room temperature, were obtained. Isothermal and nonisothermal kinetic mechanisms of cobalt grain growth were investigated. The cubic-Co grain growth activation energy, Q, was calculated in this study to be 71.47 kJ/mol. The required reaction temperature was low, making the production process simple and suitable for industrial applications.

X-ray powder diffraction studies of a new compound: Th13Te24O74

2002 ◽  
Vol 17 (1) ◽  
pp. 32-36 ◽  
Author(s):  
S. N. Tripathi ◽  
S. N. Achary ◽  
P. N. Namboodiri
Keyword(s):  
Thermal Decomposition ◽  
Solid State ◽  
Powder Diffraction ◽  
Solid State Reaction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns ◽  
Direct Solid ◽  
Measured Density

The compound Th13Te24O74 was prepared by three independent methods, namely, thermal decomposition of ThTe2O6 in oxygen and argon and direct solid-state reaction of ThO2 and TeO2. The X-ray powder diffraction patterns of the three products, by and large, are similar, except for some differences in intensities and extra diffraction lines. The thermal decomposition of ThTe2O6 was carried out in the streams of oxygen and argon by thermogravimetry at a heating rate of 5 K/min in the temperature range of 725–840 °C. The solid-state reaction of ThO2 and TeO2 (13:24) was carried out in a sealed ampoule at 700 °C. The measured density of this compound is 8.23 g/cm3. An orthorhombic lattice with unit cell parameters, a=11.310±0.005 Å, b=14.064±0.006 Å, c=9.056±0.004 Å, and volume of 1440.419±1.088 (Å)3 was determined for this compound.

Synthesis of Nanostructured Iron Oxide(III) Powders by Rapid Expansion of Supercritical Fluid Solutions

1998 ◽  
Vol 520 ◽  
Author(s):  
A.A. Burukhin ◽  
B.R. Churagulov ◽  
N.N. Oleynikov ◽  
Yu.V. Kolen'Ko
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Iron Oxide ◽  
Solid State ◽  
Supercritical Fluid ◽  
Solid State Reaction ◽  
Zinc Ferrite ◽  
Rapid Expansion ◽  
Molar Ratio ◽  
Supercritical Aqueous Solution

ABSTRACTNanostructured a-Fe2O3 powders were generated by rapid expansion of supercritical fluid solutions (RESS, T=773 K, P=100 MPa) and by rapid thermal decomposition of precursors in solution ( RTDS, T=623 K, P=100 MPa) on lab RESS-setup from 0,040 M and 0,10 M aqueous solutions of Fe(NO3)3. The size of subcrystallites is about 22-29 nm. Comparison of reactivity of α-Fe2O3 powders in a model solid state reaction between a-Fe2O3 powders (generated by RESS from 0,040 M solution) and Li2CO3 (mole ratio 1:1) with literature data on a-Fe2O3 powders produced by other methods shows that its reactivity is markedly higher. A basic essence possibility of zinc ferrite ZnFe2O4 formation immediately at the stage of the rapid expansion (T=773K; P=100 MPa) of a supercritical aqueous solution of zinc and iron nitrates (molar ratio Zn:Fe=1:2; C=0. 1 M) was shown.

Sign in / Sign up

Export Citation Format

Share Document