Abstract
This paper describes the manufacture and properties of fine scale (Ø 260 μm) and dense (>96 % theoretical density) fibres consisting of Magnéli (TinO2n-1) phases for sensing and energy storage applications. In order to understand their operational limits, the re-oxidation of the Magnéli phases in air was examined using thermo-gravimetric analysis at temperatures up to 900 °C under a variety of heating rates. The material was characterised before and after re-oxidation via X-ray diffraction and scanning electron microscopy. The re-oxidation of the Magnéli phases was observed to begin at 650 °C, and the kinetics of the process was studied using the iso-conversional method. The calculated activation energy was consistent with Jander's three-dimensional diffusion model, where oxidation is limited by diffusion of oxygen through a layer of the oxidised product. An activation energy of 0.71 eV was obtained from kinetic analysis of the thermogravimetry data, which is in agreement with previous work on electrical conduction of Magnéli phases using impedance spectroscopy.
| Language | English |
|---|---|
| Pages | 7597-7603 |
| Number of pages | 7 |
| Journal | Journal of Materials Science |
| Volume | 49 |
| Issue number | 21 |
| Early online date | 23 Jul 2014 |
| DOIs | |
| Status | Published - Nov 2014 |
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Re-oxidation mechanism and kinetics of fine scale Ti-Magnéli phases in fibre form using thermo-gravimetric analysis. / Adamaki, Vaia; Clemens, Frank; Taylor, John; Mays, Tim J.; Bowen, Christopher R.
In: Journal of Materials Science, Vol. 49, No. 21, 11.2014, p. 7597-7603.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Re-oxidation mechanism and kinetics of fine scale Ti-Magnéli phases in fibre form using thermo-gravimetric analysis
AU - Adamaki, Vaia
AU - Clemens, Frank
AU - Taylor, John
AU - Mays, Tim J.
AU - Bowen, Christopher R.
PY - 2014/11
Y1 - 2014/11
N2 - This paper describes the manufacture and properties of fine scale (Ø 260 μm) and dense (>96 % theoretical density) fibres consisting of Magnéli (TinO2n-1) phases for sensing and energy storage applications. In order to understand their operational limits, the re-oxidation of the Magnéli phases in air was examined using thermo-gravimetric analysis at temperatures up to 900 °C under a variety of heating rates. The material was characterised before and after re-oxidation via X-ray diffraction and scanning electron microscopy. The re-oxidation of the Magnéli phases was observed to begin at 650 °C, and the kinetics of the process was studied using the iso-conversional method. The calculated activation energy was consistent with Jander's three-dimensional diffusion model, where oxidation is limited by diffusion of oxygen through a layer of the oxidised product. An activation energy of 0.71 eV was obtained from kinetic analysis of the thermogravimetry data, which is in agreement with previous work on electrical conduction of Magnéli phases using impedance spectroscopy.
AB - This paper describes the manufacture and properties of fine scale (Ø 260 μm) and dense (>96 % theoretical density) fibres consisting of Magnéli (TinO2n-1) phases for sensing and energy storage applications. In order to understand their operational limits, the re-oxidation of the Magnéli phases in air was examined using thermo-gravimetric analysis at temperatures up to 900 °C under a variety of heating rates. The material was characterised before and after re-oxidation via X-ray diffraction and scanning electron microscopy. The re-oxidation of the Magnéli phases was observed to begin at 650 °C, and the kinetics of the process was studied using the iso-conversional method. The calculated activation energy was consistent with Jander's three-dimensional diffusion model, where oxidation is limited by diffusion of oxygen through a layer of the oxidised product. An activation energy of 0.71 eV was obtained from kinetic analysis of the thermogravimetry data, which is in agreement with previous work on electrical conduction of Magnéli phases using impedance spectroscopy.
UR - http://www.scopus.com/inward/record.url?scp=84906318821&partnerID=8YFLogxK
UR - http://dx.doi.org/10.1007/s10853-014-8468-9
U2 - 10.1007/s10853-014-8468-9
DO - 10.1007/s10853-014-8468-9
M3 - Article
VL - 49
SP - 7597
EP - 7603
JO - Journal of Materials Science
T2 - Journal of Materials Science
JF - Journal of Materials Science
SN - 0022-2461
IS - 21
ER -