Formation of Magnetic Properties of Ferrites During Radiation-Thermal Sintering

Stary, O.

doi:10.31489/2020no2/6-10

Cited by 10 publications

(7 citation statements)

References 17 publications

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“…A fundamental phenomenon of a multiple increase in the speed of multicomponent powder synthesis [11][12][13][14] and sintering of compacts [15][16][17][18][19] induced by radiation-thermal mode was discovered. Sintering of lithiumtitanium ferrites under specific conditions of a combined effect of high temperatures and intense electron fluxesis the most well studied process [20][21][22]. The patterns of ferrite compaction were revealed, and a multiple increase in the compaction rate of lithium-titanium ferrites under these sintering conditions was shown [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Temperature Dependences of the Initial Permeability of Lithium-Titanium Ferrites Produced by Solid-State Sintering in Thermal and Radiation-Thermal Modes

Surzhikov¹

2022

Eurasian phys. tech. j.

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The paper investigates the features of phase and structural transformations in lithium-titanium ferrites with regard to the time and temperature of solid-state sintering in thermal and radiation-thermal modes. These properties are studied with using the temperature dependence of the initial permeability. It is shown that electron beam exposure during solid-state sintering sharply accelerates the dissolution of impurity inclusions in ferrites. Also phase homogeneity of lithium-titanium ferrites products increase. The obtained results can be used for increasing of thephase homogeneity in ferrite production.

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Section: Introductionmentioning

confidence: 99%

Temperature Dependences of the Initial Permeability of Lithium-Titanium Ferrites Produced by Solid-State Sintering in Thermal and Radiation-Thermal Modes

Surzhikov¹

2022

Eurasian phys. tech. j.

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“…In the presence of fast electron exchange, regardless of the type of representation of the crystal chemical formula of the studied oxide, it contains trivalent iron ions in the tetrahedral (A) position

, trivalent iron ions in the octahedral (B) position

, as well as ions with intermediate valence in the octahedral position

), participating in the Verwey mechanism of electron exchange [ 39 , 40 ].…”

Section: Resultsmentioning

confidence: 99%

Study of Phase Transformations and Hyperfine Interactions in Fe3O4 and Fe3O4@Au Nanoparticles

et al. 2022

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The paper presents the results of a study of iron oxide nanoparticles obtained by chemical coprecipitation, coated (Fe3O4@Au) and not coated (Fe3O4) with gold, which were subjected to thermal annealing. To characterize the nanoparticles under study, scanning and transmission electron microscopy, X-ray diffraction, and Mössbauer spectroscopy on 57Fe nuclei were used, the combination of which made it possible to establish a sequence of phase transformations, changes in morphological and structural characteristics, as well as parameters of hyperfine interactions. During the studies, it was found that thermal annealing of nanoparticles leads to phase transformation processes in the following sequence: nonstoichiometric magnetite (Fe3-γO4) → maghemite (γ-Fe2O3) → hematite (α-Fe2O3), followed by structural ordering and coarsening of nanoparticles. It is shown that nanoparticles of nonstoichiometric magnetite with and without gold coating are in the superparamagnetic state with a slow relaxation rate. The magnetic anisotropy energy of nonstoichiometric magnetite is determined as a function of the annealing temperature. An estimate was made of the average size of the region of magnetic ordering of Fe atoms in nonstoichiometric magnetite, which is in good agreement with the data on the average sizes of nanoparticles determined by scanning electron microscopy.

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“…The stability of nanoparticles is determined by the amount of weight loss, as well as the crystallinity degree (degree of structural ordering), which should not exceed 10% of the initial values. At the same time, several previous studies have shown that the processes of corrosion and degradation of nanoparticles have a pronounced dependence on the phase composition of nanoparticles, as well as the structural ordering degree [11,19].…”

Section: Corrosion Resistance Testsmentioning

confidence: 93%

Study of the Applicability of Magnetic Iron-Containing Nanoparticles in Hyperthermia and Determination of Their Resistance to Degradation Processes

et al. 2022

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The article presents the results of evaluating the applicability of various types of iron-containing nanoparticles in magnetic hyperthermia, as well as determining the degradation resistance of nanoparticles. The objects of study were iron-containing nanoparticles obtained by chemical precipitation and subsequent modification with gold, gadolinium, and neodymium. The main methods for studying the properties of the synthesized nanoparticles were transmission electron microscopy, X-ray phase analysis, and Mössbauer spectroscopy. Evaluation of the efficiency of the use of the synthesized nanoparticles in magnetic hyperthermia showed that Fe3O4@GdFeO3 nanoparticles, for which the specific absorption rate was more than 120 W/g, have the highest efficiency. An assessment of the resistance of the synthesized nanoparticles to corrosion in water at different temperatures showed that Fe2O3@NdFeO3 and Fe3O4@GdFeO3 nanoparticles have the highest resistance to degradation. It has been established that in the case of the initial Fe3O4 nanoparticles, the degradation processes are accompanied by partial destruction of the particles, followed by amorphization and destruction, while for Fe2O3@NdFeO3 and Fe3O4@GdFeO3 nanoparticles, the degradation processes proceed much more slowly, due to the presence of interfacial boundaries, which slow down the corrosion processes. The obtained results of corrosion tests in aqueous media make it possible to predict the area and time frame of applicability of iron-containing nanoparticles when using them in the biomedical direction, as well as to determine storage conditions.

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Formation of Magnetic Properties of Ferrites During Radiation-Thermal Sintering

Cited by 10 publications

References 17 publications

Temperature Dependences of the Initial Permeability of Lithium-Titanium Ferrites Produced by Solid-State Sintering in Thermal and Radiation-Thermal Modes

Temperature Dependences of the Initial Permeability of Lithium-Titanium Ferrites Produced by Solid-State Sintering in Thermal and Radiation-Thermal Modes

Study of Phase Transformations and Hyperfine Interactions in Fe3O4 and Fe3O4@Au Nanoparticles

Study of the Applicability of Magnetic Iron-Containing Nanoparticles in Hyperthermia and Determination of Their Resistance to Degradation Processes

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