Technological Aspects of Lithium-Titanium Ferrite Synthesis by Electron-Beam Heating

Solid-phase synthesis of lithium-titanium ferrite by electron-beam heating of a Fe₂O₃-Li₂CO₃-TiO₂ initial reagents mixture with different history (powder, compact, mechanically activated mixture) was studied using X-ray diffraction, thermomagnetometric and specific saturation magnetization analyses. Ferrite was synthesized using an ILU-6 pulsed electron accelerator; it generated electrons with electron energy of 2.4 MeV to heat samples to temperatures of 600 and 750 °C. The isothermal holding time upon reaching the synthesis temperature was 0-120 min. The efficiency of ferrite synthesis by electron-beam heating was evaluated via comparison of the characteristics of the obtained samples with those synthesized by conventional ceramic technology under similar temperature-time conditions. It was found that the rate of ferrite formation depends on the heating method, temperature, synthesis time, density, and activity of the initial mixture. It was shown that sample compaction provides the preferential formation of unsubstituted lithium ferrite of Li_0.5Fe_2.5O₄ composition with a Curie temperature of at ca. 630 °C in both synthesis methods. High-energy electron-beam heating of the mechanically activated mixture significantly accelerates synthesis of Li_0.6Fe_2.2Ti_0.2O₄ substituted ferrite, for which the Curie temperature and specific saturation magnetization were recorded as 534 °C and 50 emu/g, respectively. Therefore, LiTi ferrites can be obtained at a lower temperature (750 °C) and with a shorter synthesis time (120 min) compared to traditional ceramic technology.