Thermal kinetic analysis of a complex process from a solid-state reaction by deconvolution procedure from a new calculation method and related thermodynamic functions of Mn0.90Co0.05Mg0.05HPO4·3H2O

AbstractNon-isothermal reaction mechanism and kinetic analysis for the synthesis of monoclinic lithium zirconate (m-Li2ZrO3) were investigated by processing of TG-DTA, along with XRD, DLS, and HRTEM. For this purpose, the solid-state reaction of Li2CO3 with ZrO2 was carried out by TG-DTA at different heating rates (10, 20, and 30 °C/min) from room temperature to 1100 °C. The thermal data was used to calculate the kinetic parameters by two types of isoconversional methods: Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS). The reaction mechanism was determined by the model-fitting method, applying the Coats-Redfern (CR) approximation to the different solid-state reaction models. The results confirmed the formation of pure m-Li2ZrO3, consists of semispherical particles of about 490 nm, using a very short reaction time. The average activation energy obtained by FWO and KAS methods were 274.73 and 272.50 kJ/mol, respectively. It was found that the formation of m-Li2ZrO3 from Li2CO3 with ZrO2 is governed by the three-dimensional diffusion mechanism. Based on these results, a microscopic reaction model of the formation of m-Li2ZrO3 was proposed.

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

Canadian Journal of Chemistry ◽

10.1139/v92-118 ◽

1992 ◽

Vol 70 (3) ◽

pp. 888-893 ◽

Cited By ~ 3

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.

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Reaction Mechanism and Kinetic Analysis of the Decomposition of Phosphogypsum via a Solid-State Reaction

Industrial & Engineering Chemistry Research ◽

10.1021/ie901950y ◽

2010 ◽

Vol 49 (8) ◽

pp. 3597-3602 ◽

Cited By ~ 48

Author(s):

Liping Ma ◽

Ping Ning ◽

Shaocong Zheng ◽

Xuekui Niu ◽

Wei Zhang ◽

...

Keyword(s):

Reaction Mechanism ◽

Solid State ◽

Kinetic Analysis ◽

Solid State Reaction

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The wustite-spinel interface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126226 ◽

1987 ◽

Vol 45 ◽

pp. 268-269

Author(s):

S.R. Summerfelt ◽

C.B. Carter

Keyword(s):

Solid State ◽

Solid State Reaction ◽

Strain Energy ◽

Matrix Material ◽

Lattice Misfit ◽

Solid State Reactions ◽

Oxygen Sublattice ◽

Large Particles ◽

Small Lattice ◽

Coherent Interfaces

The wustite-spinel interface can be viewed as a model interface because the wustite and spinel can share a common f.c.c. oxygen sublattice such that only the cations distribution changes on crossing the interface. In this study, the interface has been formed by a solid state reaction involving either external or internal oxidation. In systems with very small lattice misfit, very large particles (>lμm) with coherent interfaces have been observed. Previously, the wustite-spinel interface had been observed to facet on {111} planes for MgFe2C4 and along {100} planes for MgAl2C4 and MgCr2O4, the spinel then grows preferentially in the <001> direction. Reasons for these experimental observations have been discussed by Henriksen and Kingery by considering the strain energy. The point-defect chemistry of such solid state reactions has been examined by Schmalzried. Although MgO has been the principal matrix material examined, others such as NiO have also been studied.

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Observation of solid-state reaction between a thin yttria film and a (0001) α-alumina substrate

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170955 ◽

1994 ◽

Vol 52 ◽

pp. 644-645

Author(s):

J. R. Heffelfinger ◽

C. B. Carter

Keyword(s):

Electron Microscopy ◽

Solid State ◽

Solid State Reaction ◽

Yttrium Aluminum Garnet ◽

Secondary Phase ◽

Ceramic Composites ◽

Alumina Substrate ◽

Transmission Electron ◽

Alumina Fibers ◽

Optical Applications

Transmission-electron microscopy (TEM), scanning-electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) were used to investigate the solid-state reaction between a thin yttria film and a (0001) α-alumina substrate. Systems containing Y2O3 (yttria) and Al2O3 (alumina) are seen in many technologically relevant applications. For example, yttria is being explored as a coating material for alumina fibers for metal-ceramic composites. The coating serves as a diffusion barrier and protects the alumina fiber from reacting with the metal matrix. With sufficient time and temperature, yttria in contact with alumina will react to form one or a combination of phases shown by the phase diagram in Figure l. Of the reaction phases, yttrium aluminum garnet (YAG) is used as a material for lasers and other optical applications. In a different application, YAG is formed as a secondary phase in the sintering of AIN. Yttria is added to AIN as a sintering aid and acts as an oxygen getter by reacting with the alumina in AIN to form YAG.

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