Microstructure and thermal analysis of lithium ferrite pre-milled in a high-energy ball mill

Lysenko, Elena; Малышев, А. В.; Vlasov, V. A.; Nikolaev, E. V.; Суржиков, А. П.

doi:10.1007/s10973-018-7549-4

Cited by 27 publications

(11 citation statements)

References 35 publications

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“…The details of the crystal data and the selected crystallographic parameters are presented in Table 1. The lattice parameters of lithium ferrite obtained at a stoichiometric ratio of glycine to nitrogen in nitrates (a = 8.324(4) Å) are in good agreement with the reported values of α-Li 0.5 Fe 2.5 O 4 [28]. In other samples, it was determined that the lattice parameters of the prepared lithium ferrite powders are quite lower (a = 8.290(2) Å).…”

Section: Resultssupporting

confidence: 87%

Effect of the Red / Ox ratio on the structure and magnetic behavior of Li0.5Fe2.5O4 nanocrystals synthesized by solution combustion approach

et al. 2019

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In this research, nanocrystalline lithium ferrite (Li 0.5 Fe 2.5 O 4 ) was synthesized using the solution combustion approach with using glycine as fuel and a chelating agent at various Red / Ox ratios ("glycine to nitrate" ratio G / N = 0.4, 0.6, 0.8, 1.0). According to the data of energy-dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS), the prepared samples correspond in their composition to stoichiometric ferrite Li 0.5 Fe 2.5 O 4 within the error of the determination methods used. The results of powder X-ray diffractometry (PXRD) confirmed the formation of α-Li 0.5 Fe 2.5 O 4 at G / N ratio of 0.8 and 1.0 and the presence of β-Li 0.5 Fe 2.5 O 4 modification in case of deficiency (G / N = 0.4) and stoichiometry (G / N = 0.6) of the chelating agent. It is shown that a change in the Red / Ox composition of reacting solutions affects not only the phase composition of the synthesized lithium ferrite samples, but also the crystallite size, which lies in the range from 22 to 35 nm. Based on the scanning electron microscopy (SEM) data, it was found that Li 0.5 Fe 2.5 O 4 powders had a developed porous microstructure consisting of micron agglomerates. According to the vibration magnetometry data of nanocrystalline lithium ferrite powders, it follows that all synthesized compositions have a pronounced ferrimagnetic behavior, despite the presence of β-modification in some of them. It is shown that by varying the Red / Ox environment and, as a consequence, the phase composition and crystallite size, it is possible to obtain Li 0.5 Fe 2.5 O 4 nanocrystals with magnetic parameters in the following ranges: saturation magnetization (M s ) = 51.6 -61.9 emu / g, residual magnetization (M r ) =14.3 -17.8 emu / g, coercive force (H c ) =109 -135 Oe.

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Section: Resultssupporting

confidence: 87%

Effect of the Red / Ox ratio on the structure and magnetic behavior of Li0.5Fe2.5O4 nanocrystals synthesized by solution combustion approach

et al. 2019

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“…The TG curves measured using a magnetic field show an abrupt increase in mass near the Curie temperature (T c ), which can be determined from the DTG curves. The T c for samples S1 and S2 attains 629.2 and 629.7 °C, respectively, and these values are close to the temperature of the magnetic transition in ordered lithium ferrite with T c = 632 °C [26,68]. As reported in [72], a slight decrease in the Curie temperature of the samples can be associated with an increase in the degree of the order violation in the ferrite structure.…”

Section: Thermal Analysis Of Precursors and Synthesized Ferritessupporting

confidence: 73%

“…2b and 3b). The obtained enthalpy values of 8.9 J g −1 and 8.2 J g −1 for samples S1 and S2, respectively, are very close to the transition enthalpy for pure lithium ferrite with the DSC peak equal to 12 J g −1 [26].…”

Section: Thermal Analysis Of Precursors and Synthesized Ferritessupporting

confidence: 69%

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TG, DSC, XRD, and SEM studies of the substituted lithium ferrite formation from milled Sm2O3/Fe2O3/Li2CO3 precursors

Lysenko

Vlasov²,

Nikolaeva³

et al. 2022

J Therm Anal Calorim

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Formation of substituted lithium ferrite Li 0.5 Sm x Fe 2.5-x O 4 (where x = 0.06 and 0.2) from Sm 2 O 3 /Fe 2 O 3 /Li 2 CO 2 precursors was studied by X-ray diffraction analysis, thermogravimetry, differential scanning calorimetry, and scanning electron microscopy. The mixture of powders was subjected to preliminary mechanical activation in a planetary mill. We analyzed samples based on the precursors and synthesized at 900 °C for 4 h in a laboratory furnace. It was found that ball milling of the precursors mixture in a planetary mill increases the powder reactivity. In spite of this, no substituted lithium ferrites were formed. It was shown that a two-phase composite that consists of pure lithium ferrite Li 0.5 Fe 2.5 O 4 and SmFeO 3 is formed during synthesis. An increase in the Sm 2 O 3 content in the initial mixture provides an increase in the amount of the formed SmFeO 3 phase. The synthesis of Li 0.5 Fe 2.5 O 4 ferrite was confirmed by XRD analysis data, the Curie temperature (627-630 °C) measured using TG analysis in a magnetic field, and by the presence of an endothermic peak on the DSC curve corresponding to the order-disorder transition in the Li 0.5 Fe 2.5 O 4 phase.

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“…High synthesis temperatures lead to the volatility of lithium and oxygen at temperatures above 1000 °C resulting in the magnetic properties deterioration, and dielectric losses increasing in ferrite ceramics [4]. Several wet chemical methods, including self-combustion [5,6], hydrothermal ball milling [7][8][9], the method of citrate precursor [10], and sol-gel synthesis [11,12], have been developed. These methods are utilized to obtain lithium ferrite at lower temperatures, as well as to minimize side phase inclusions and defects featured to ceramic technology.…”

Section: Introductionmentioning

confidence: 99%

Impact of ZrO2 additive on the microstructure, magnetic properties, and temperature dependence of the initial permeability of LiTiZn ferrite ceramics

Малышев

Petrova

Суржиков

2021

J Mater Sci: Mater Electron

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The effect of the diamagnetic ZrO2 addition on the microstructure and magnetic properties of LiTiZn ferrite ceramics, including the shape and parameters of the temperature dependence of the initial permeability, has been investigated. The defect structure of ferrite ceramic samples is assessed according to our earlier proposed method based on mathematical treatment of the experimental temperature dependencies of the initial permeability. The method is recommended for defects monitoring of soft ferrite ceramics and ferrite products. It was found that the defect structure of ferrite ceramics increased by 350% with an increase in the concentration of the ZrO2 additive in the range of (0-0.5) wt.%. In this case, for the same samples, the increase in the true physical broadening of reflections is only 20%, and the coercive force by 50%. Simultaneously, the maximum of the experimental temperature dependence of the initial permeability dropped by 45%.The microstructure of all samples is characterized with a similar average grain size according to the SEM data. However, samples with the 0.5wt.% of ZrO2 are characterized by the formation of conglomerates. A linear relationship was obtained between the defect structure and the width of the reflections, which indicates that this parameter is related to the elastic stress of ferrite ceramics.

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Microstructure and thermal analysis of lithium ferrite pre-milled in a high-energy ball mill

Cited by 27 publications

References 35 publications

Effect of the Red / Ox ratio on the structure and magnetic behavior of Li0.5Fe2.5O4 nanocrystals synthesized by solution combustion approach

Effect of the Red / Ox ratio on the structure and magnetic behavior of Li0.5Fe2.5O4 nanocrystals synthesized by solution combustion approach

TG, DSC, XRD, and SEM studies of the substituted lithium ferrite formation from milled Sm2O3/Fe2O3/Li2CO3 precursors

Impact of ZrO2 additive on the microstructure, magnetic properties, and temperature dependence of the initial permeability of LiTiZn ferrite ceramics

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