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      https://www.ias.ac.in/article/fulltext/boms/013/04/0293-0300

    • Keywords

       

      MgAl2O4; spinel; electrical conductivity; conductivity mechanism; ionic transport

    • 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.

    • Author Affiliations

       

      Tom Mathews1 K T Jacob1 J P Hajra1

      1. Department of Metallurgy, Indian Institute of Science, Bangalore - 560 012, India
    • Dates

       
  • Bulletin of Materials Science | News

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