scholarly journals Kinetics of Formation of SrWO4 in the Solid State Reaction Between WO3 and SrCO3

1974 ◽  
Vol 29 (3) ◽  
pp. 503-506 ◽  
Author(s):  
Giorgio Flor ◽  
Vincenzo Massarotti ◽  
Riccardo Riccardi
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Powder Mixtures ◽  
Temperature Range ◽  
Kinetics Of Formation ◽  
Kinetics Of

The solid state reaction WO3 + SrCO3 → SrWO4 + CO2 was studied with the reactants in form both of separate pellets and of powder mixtures.As for pellets, by an application of Wagner’s method it was possible to state that the governing process is the cation counterdiffusion involving W6+ and Sr2+.Thermogravimetric measurements in the temperature range 663° - 755 °C on equimolar powder mixtures and with SrCO3 in a specially prepared spherulitic form were interpreted using Dünwald- Wagner’s equation

Kinetics of Formation of RuSr2GdCu2O8 by Solid-State Reaction of Sr2CdRuO6 and CuO.

ChemInform ◽  
2003 ◽  
Vol 34 (41) ◽  
Author(s):  
Chen Shaou ◽  
H. F. Braun ◽  
T. P. Papageorgiou
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Kinetics Of Formation ◽  
Kinetics Of

Synthesis and Kinetics of Formation of Bismuth Ferrite (BFO) by Solid-State Reaction Under O 2 and N 2

2021 ◽  
Author(s):  
Kananda M. Degues ◽  
Fábio Elyseu ◽  
Adriano Michael Bernardin ◽  
Luciana M. Schabbach ◽  
Márcio C. Fredel
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Bismuth Ferrite ◽  
Kinetics Of Formation ◽  
Kinetics Of

scholarly journals Kinetics of MgWO4 Formation in the Solid State Reaction between MgO and WO3

1976 ◽  
Vol 31 (6) ◽  
pp. 619-621 ◽  
Author(s):  
Giorgio Flor ◽  
Riccardo Riccardi
Keyword(s):  
Solid State ◽  
Kinetic Study ◽  
Single Crystals ◽  
Solid State Reaction ◽  
Argon Atmosphere ◽  
Conductivity Measurements ◽  
Linear Rate ◽  
Rate Law ◽  
Temperature Range ◽  
Kinetics Of

The solid state reaction of MgWO4 formation from MgO (single crystals) and WO3 was investigated in the temperature range 800 - 985 °C under both air and argon atmosphere.The techniques employed for the kinetic study (contact and thermogravimetric methods) allowed to point out that the process follows the linear rate law in the early stages and the parabolic one in the subsequent stages.From inert marker experiments, kinetic determinations under the two different atmospheres and conductivity measurements, it was possible to state that the reaction is governed by a cation counterdiffusion mechanism

Kinetics of the Solid State Reaction between MoO3 and SrCO3

1972 ◽  
Vol 27 (6) ◽  
pp. 1020-1022 ◽  
Author(s):  
G. Flor ◽  
V. Massarotti ◽  
R. Riccardi
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Apparent Activation Energy ◽  
Solid State Reaction ◽  
Diffusion Mechanism ◽  
Optical Observations ◽  
Kcal Mole ◽  
Temperature Range ◽  
Kinetics Of

AbstractThe solid state reaction MoO3 + SrCO3 → SrMoO4+ CO2 has been studied on mixtures of powdered reagents. Thermogravimetric measurements in the temperature range 412° -498 °C have been made on different mixtures and under different atmospheres. Moreover, optical observations and conductometric measurements have been carried out. The results show that the reaction is governed by a diffusion mechanism with an apparent activation energy of (60 ± 1) kcal/mole and that the main diffusing species is the Mo6+ ion.

Thermoelectric Properties of High Density Sintered Ca3Co2O6

2008 ◽  
Vol 54 ◽  
pp. 211-215 ◽  
Author(s):  
Takeo Uesugi ◽  
Hitoshi Kohri ◽  
Ichiro Shiota ◽  
Masahiko Kato ◽  
Isao J. Ohsugi
Keyword(s):  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Hot Pressing ◽  
Temperature Limit ◽  
Thermoelectric Oxide ◽  
Temperature Range ◽  
Seebeck Coefficients ◽  
The One ◽  
Lower Resistivity

Ca3Co4O9 is a promising material for thermoelectric generation, as it is stable up to 1173 K in the air, and shows good thermoelectric properties. Recently, it was found that Ca3Co2O6 was stable up to 1300 K in the air. The Ca3Co2O6 is decomposed phase of Ca3Co4O9 and the temperature limit is higher than one of Ca3Co4O9. The electrical resistivity of Ca3Co2O6 was, however, higher than the one of Ca3Co4O9. Not only high power generation performances but also excellent strength is required for practical use of the thermoelectric oxide materials. Polycrystalline samples of Ca3Co2O6 were prepared by solid-state reaction (SSR) and hot pressing (HP). Relative density of Ca3Co2O6 (HP) was over 98%, which is larger than the one of Ca3Co2O6 (SSR). Ca3Co2O6 (HP) showed larger strength and lower resistivity than Ca3Co2O6 (SSR). The resistivity (ρ) of Ca3Co2O6 (HP) in perpendicular to the pressurized direction decreased from 64 Ωcm to 4.0×10-2 Ωcm at the temperature range between 373 and 1173 K. In addition, the resistivity of this sample was decreased by heat treatment in the air. The Seebeck coefficients (S) of Ca3Co2O6 (HP) was positive value and more than 160 μVK-1 at the temperature range between 373 and 1173 K. Ca3Co1.8M0.2O6 (M= Mn or V) were prepared by solid state reaction and hot pressing. The resistivity of Mn-substituted Ca3Co2O6 (HP-Mn) and V-substituted Ca3Co2O6 (HP-V) were lower than the one of non-substituted Ca3Co2O6 (HP) at the temperature below 523 K for the Mn-substituted sample or 723 K for V-substituted sample. The latter showed the lowest value 1.53 Ωcm of all specimens at 383 K. The power factor (S2ρ-1) of Ca3Co2O6 (HP) was 88.3 μWm-1K-2, which is the largest of all specimens at 1176 K, but S2ρ-1 of V-substituted Ca3Co2O6 (HP-V) is the largest of all specimens up to 773 K.

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