Electron-Microscopic Study of Morphology and Phase Composition of Lithium-Titanium Ferrites

Abstract

In the present paper, the phase composition and morphology of lithium-titanium ferrospinel, synthesized by ceramic technology and subjected to thermal (T) and radiation-thermal (RT) annealing at a temperature of 1373 K, are studied. RT annealing of samples was performed by heating radiation of high-power electron beam pulses with energy 1.8 MeV. Bulk-density powders and powders compacted under a pressure of 1200 kg/cm² were used as samples. The results obtained indicate the polyphase composition of initial powders. Annealing decreases the relative content of the secondary LiFeO₂-based phase and increases the relative content of the master LiFe₅O₈-based phase. The efficiency of this process depends on the powder compactness and the heating regime. RT annealing significantly increases the rate of dissolution of the LiFeO₂-based phase. An impact diffraction analysis has shown that the secondary phases have polycrystalline structures, whereas the LiFe₅O₈-based phase is formed by monocrystalline particles. Annealing of the compacted powder by an electron beam completely eliminates polycrystalline aggregates with ultradisperse grained structure.