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

Abstract

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 Li0.5Fe2.5O4 composition with a Curie temperature of at ca. 630 °С in both synthesis methods. High-energy electron-beam heating of the mechanically activated mixture significantly accelerates synthesis of Li0.6Fe2.2Ti0.2O4 substituted ferrite, for which the Curie temperature and specific saturation magnetization were recorded as 534 °С 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.

Synthesis and Oxygen Mobility of Bismuth Cerates and Titanates with Pyrochlore Structure

“…With traditional thermal sintering in a furnace, long-term processing, and high temperatures are required to obtain ceramics with desired properties, such as gas tightness, homogeneous phase composition, etc. To solve this problem, radiation-thermal sintering (e-beam processing) is proposed [ 37 , 38 , 39 , 40 , 41 ]. Using the main advantages of radiation-thermal reactions—lowering the treatment temperature and a high reaction rate—will reduce the processing time while also significantly reducing internal thermal stresses.…”

“…structures or their nanocomposites, such as LFN-GDC, LFC-GDC, La 0.3 Bi 0.7 MnO x –Bi 1.5 Y 0.3 Sm 0.2 O 3 , etc.) using unique equipment of the Budker Institute of Nuclear Physics [ 37 , 38 , 39 , 40 , 41 ]. Disordering of nanodomains by electron beams leads to their easy sintering at moderate temperatures without increasing their sizes.…”

“…Disordering of nanodomains by electron beams leads to their easy sintering at moderate temperatures without increasing their sizes. This results in a developed network of domain boundaries, which, for nanocomposites [ 37 , 38 , 39 , 40 , 41 ] or even some complex oxides (such as molybdates of lanthanoids [ 42 ], etc. ), provide fast oxygen diffusion channels described by the so-called 2D model of oxygen diffusion.…”