Activation energy determination for linear heating experiments: deviations due to the low temperature end of the temperature integral
Activation energy determination for linear heating experiments: deviations due to the low temperature end of the temperature integral
Model-free isoconversion methods which use approximations of the temperature integral are generally reliable methods for the calculation of activation energies of thermally activated reactions studied during linear heating. These methods generally neglect the temperature integral at the start of the linear heating, I(To). An analytical equation is derived which describes the deviations introduced by this approximation. It is shown that for most reactions encountered this assumption does not have a significant influence on the accuracy of the method. However, in cases where To is within about 50 to 70K of the reaction stage to be investigated and activation energies are relatively low, significant deviations are introduced. It is shown that some of the published thermal analysis work on activation energy analysis of reaction occurring at relatively low temperatures is affected by these deviations. Examples are specific cases of dehydration reactions, cure reactions and cluster formation in Al alloys.
thermally activated reaction, activation energy, thermal analysis, linear heating, curing, DSC, crystallisation, diffusion, polymer, metal, alloy, Al-Cu-Mg, temperature integral, Arrhenius integral, hydrated, Co(II) methanesulfonate
483-489
Starink, M.J.
fe61a323-4e0c-49c7-91f0-4450e1ec1e51
2007
Starink, M.J.
fe61a323-4e0c-49c7-91f0-4450e1ec1e51
Starink, M.J.
(2007)
Activation energy determination for linear heating experiments: deviations due to the low temperature end of the temperature integral.
Journal of Materials Science, 42, .
(doi:10.1007/s10853-006-1067-7).
Abstract
Model-free isoconversion methods which use approximations of the temperature integral are generally reliable methods for the calculation of activation energies of thermally activated reactions studied during linear heating. These methods generally neglect the temperature integral at the start of the linear heating, I(To). An analytical equation is derived which describes the deviations introduced by this approximation. It is shown that for most reactions encountered this assumption does not have a significant influence on the accuracy of the method. However, in cases where To is within about 50 to 70K of the reaction stage to be investigated and activation energies are relatively low, significant deviations are introduced. It is shown that some of the published thermal analysis work on activation energy analysis of reaction occurring at relatively low temperatures is affected by these deviations. Examples are specific cases of dehydration reactions, cure reactions and cluster formation in Al alloys.
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Activation_energy_determination_for_.._by_Starink_J_Mater_Sci_2007_web_iii.pdf
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Published date: 2007
Keywords:
thermally activated reaction, activation energy, thermal analysis, linear heating, curing, DSC, crystallisation, diffusion, polymer, metal, alloy, Al-Cu-Mg, temperature integral, Arrhenius integral, hydrated, Co(II) methanesulfonate
Identifiers
Local EPrints ID: 19255
URI: http://eprints.soton.ac.uk/id/eprint/19255
ISSN: 0022-2461
PURE UUID: c4b00f16-f9bd-484f-88d3-b748e5b5abe9
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Date deposited: 30 Jan 2006
Last modified: 15 Mar 2024 06:13
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