Investigation of oxidation processes in non-stoichiometric lithium-titanium ferrites using TG analysis

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Abstract

Using non-isothermal thermogravimetry (TG), the oxidation kinetics of oxygen-deficient lithium-titanium ferrospinel, Li0.649Fe 1.598Ti0.5Zn0.2Mn0.051O 4-δ, manufactured by ceramic engineering is investigated. The oxidation annealing of powder samples is performed in air. According to the X-ray phase analysis, the processes giving rise to variations in oxygen content occur within single-phase spinel structure. The experimental kinetic results are processed using the Netzsch Thermokinetics software. The oxidation rate constants and the effective coefficients of atmospheric oxygen diffusion into the ferrites are determined. The effective activation energy E of oxygen diffusion is found to be 1.95 eV. It is demonstrated that an increase in the oxygen non-stoichiometry parameter δ as a result of recovery annealing of ferrite powders in vacuum at T = 1,070 K for 2 h gives rise to a slight decrease in E down to 1.89 eV. The activation energy of oxygen grain-boundary diffusion is identified by the electroconduction method. The resulting value 1.93 eV is fairly consistent with that obtained by TG.

Original languageEnglish
Pages (from-to)883-887
Number of pages5
JournalJournal of Thermal Analysis and Calorimetry
Volume102
Issue number3
DOIs
Publication statusPublished - Dec 2010

Keywords

  • Kinetics
  • Oxidation of lithium-titanium ferrites
  • Oxygen diffusion
  • TG

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Condensed Matter Physics

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