Methodology of Thermal Research in Materials Engineering

Biedunkiewicz, A.

doi:10.5772/51415

Cited by 2 publications

(5 citation statements)

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“…It should be added that in order to perform calculations numerically one needs to know temperature ranges T a=0 ; T a=1 for each heating rate and for each stage. Equation (10) will be used to determine kinetic models [4]. A good approximation (10), easier for use in kinetic calculations, is the CoatsRedfern Eq.…”

Section: Methods Of Calculationsmentioning

confidence: 99%

“…In theory of kinetics of non-catalytic heterogeneous reactions, it is assumed that the reaction rate depends on temperature and conversion degree [1][2][3][4][5] …”

Section: Introductionmentioning

confidence: 99%

“…This notation indicates that under non-isothermal conditions, at a constant sample heating rate, for each stage of the process, the form of the function k(T), and thus the parameters A and E of the form of the function f(a) should be maintained [4,14]. The influence of the sample heating rate (b) on the course of transformations should be compensated by temperature range T a=0 ; T a=1 [4].…”

Section: Introductionmentioning

confidence: 99%

“…The influence of the sample heating rate (b) on the course of transformations should be compensated by temperature range T a=0 ; T a=1 [4].…”

Section: Introductionmentioning

confidence: 99%

“…In our work we do not include the results obtained by isoconversional method. The results of such calculations are given in work [4].…”

Section: Introductionmentioning

confidence: 99%

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Analysis of (NH4)6Mo7O24·4H2O thermal decomposition in argon

Biedunkiewicz

Krawczyk

Gabriel-Półrolniczak

et al. 2013

J Therm Anal Calorim

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Nanometric carbides of transition metals and silicon are obtained by using precursors. Control of the course of these processes require data concerning transformations of single precursor, transformations of precursor in the presence of reducing agent and synthesis of the carbide. In this work, the way of investigating such processes is described on the example of thermal decomposition of (NH 4 ) 6 Mo 7 O 24 Á4H 2 O (precursor) in argon. The measurements were carried out by TG-DSC method. The solid products were identified by XRD method, and the gaseous products were determined by mass spectrometry method. There was demonstrated that the investigated process proceeded in five stages. Kinetic models (forms of f(a) and g(a) function) most consistent with experimental data and coefficients of Arrhenius equation A and E were determined for the stages. The Kissinger method and the Coats-Redfern equation were applied. In case of the Coats-Redfern equation, the calculations were performed by analogue method. In this way good consistency between the calculated and determined conversion degrees a(T) at practically constant values of A and E were obtained for distinguished stages and different sample heating rates.Keywords Decomposition of (NH 4 ) 6 Mo 7 O 24 Á4H 2 O in argon Á Thermal analysis Á Process kinetics Á Kissinger method Á Coats-Redfern equation Abbreviations APre-exponential Arrhenius factor/1 minConversion function dependent on mechanism of reaction f 0 (a m ) Derivative of f(a) function for maximal reaction rate u(T, a, P) Temperature, conversion degree and pressure function g(a)Integral form of kinetic model h(P)Pressure function k(T)Reaction rate constant/1 min

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Section: Methods Of Calculationsmentioning

confidence: 99%

“…In theory of kinetics of non-catalytic heterogeneous reactions, it is assumed that the reaction rate depends on temperature and conversion degree [1][2][3][4][5] …”

Section: Introductionmentioning

confidence: 99%