Electrical transport in magnesium aluminate

Mathews, Tom and Jacob, KT and Hajra, JP (1990) Electrical transport in magnesium aluminate. In: Bulletin of Materials Science, 13 (4). pp. 293-300.

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Abstract

The conductivity of MgAl2O4 has been measured at 1273, 1473 and 1673 K as a function of the partial pressure of oxygen ranging from 105 to 10−14 Pa. The MgAl2O4 pellet, sandwiched between two platinum electrodes, was equilibrated with a flowing stream of either Ar + O2, CO + CO2 or Ar + H2 + H2O mixture of known composition. The gas mixture established a known oxygen partial pressure. All measurements were made at a frequency of 1 kHz. These measurements indicate pressure independent ionic conductivity in the range 1 to 10−14 Pa at 1273 K, 10−1 to 10−12 Pa at 1473 K and 10−1 to 10−4 Pa at 1673 K. The activation energy for ionic conduction is 1·48 eV, close to that for self-diffusion of Mg2+ ion in MgAl2O4 calculated from the theoretical relation of Glyde. Using the model, the energy for cation vacancy formation and activation energy for migration are estimated.

Item Type:	Journal Article
Publication:	Bulletin of Materials Science
Publisher:	Indian Academy of Sciences
Additional Information:	Copyright of this article belongs to Indian Academy of Sciences.
Keywords:	spinel;electrical conductivity;conductivity mechanism;ionic transport.
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	10 Feb 2011 10:42
Last Modified:	10 Feb 2011 10:42
URI:	http://eprints.iisc.ac.in/id/eprint/35130

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