12 research outputs found
The Physical Model of Formation of Hexagonal Ferrites BaFe12O19
To identify the features of structural transformations occurring during the formation of the crystal lattice
of hexagonal barium ferrite were studied the following issues: a) component defined that are structural
element in the reaction of solid-phase synthesis of ferrites BaFe12O19; b) the phase composition set of the
reaction products formed in mixtures of BaCО3 – Fe2O3; c) a crystal-chemical model developed allows visually describe the transformation of -Fe2O3 – BaFe12O19
The Physical Model of Formation of Hexagonal Ferrites BaFe12O19
To identify the features of structural transformations occurring during the formation of the crystal lattice
of hexagonal barium ferrite were studied the following issues: a) component defined that are structural
element in the reaction of solid-phase synthesis of ferrites BaFe12O19; b) the phase composition set of the
reaction products formed in mixtures of BaCО3 – Fe2O3; c) a crystal-chemical model developed allows visually describe the transformation of -Fe2O3 – BaFe12O19
Influence of Magnetic Pulseprocessing on Oxide Materials Physics and Mechanical Properties
Internal stresses, specific single-crystal blocks, stoichiometric impurity of oxides composition and other
factors lead to low strength properties of ferromagnetic iron oxides. Weakening of such defects and increa s-ing iron oxides microhardness, their fracture and mechanic strength are possible by using magnetic pulse
processing. The results of experimental studies of the magnetic pulse field effecting on the iron oxides
strength properties are shown. Mössbauer spectroscopy, porosimetry, X-ray structure analysis are used to
find the mechanisms of this effect. The strength properties change is the result of set of microscopic and
quantum effects superposition. It provides easy defects restructuring of solids: vacancies, dislocations,
voids.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3636
Magnetic Properties and Local Parameters of Crystal Structure for BaFe[12]O[19] and SrFe[12]O[19] Hexagonal Ferrites
It is shown that difference between magnetic properties of hexagonal ferrites BaFe[12]O[19] and SrFe[12]O[19] is connected with difference of electronic configurations of Ba2+ and Sr2+ ions, and their ionic radii. Replacement
of Ba2+ ions by Sr2+ ions that are smaller in size effects the degree of distortions of octahedrons located either in a hexagonal R-block or at its boundary with S-block. It contributes to a preferred localization of electrically active vacancies at the boundary of R- and S-block
The Formation and Study of the FeCo Nanoparticles Alloy in Structure of Metal-Carbon Nanocomposites FeCo/C
The study of the peculiarities of the formation of the nanoparticles FeCo-alloy in the composition of
metal-carbon nanocomposites FeCo/C.
Structure, phase composition and kinetic processes of synthesis of nanocomposites FeCo/C by methods
of Mossbauer spectroscopy were studied. This allowed us to establish the peculiarities of formation of nanoparticles
FeCo alloy in the composition of the nanocomposites. The nanocomposites were synthesized by
the IR-pyrolysis at temperatures of precursors of 300 - 800 °C on the basis of polyacrylonitrile (PAN), iron
acetylacetonate and cobalt acetate.
Also it is established that an increase in the average size of nanoparticles FeCo with increasing temperature
synthesis is occurred. In the temperature range of synthesis of 600-800 °C the size varies from 9-
10 to 16-18 nm, respectively.
The features the phase transitions and phase composition of the metal-carbon nanocomposites FeCo / C
were studied by Mossbauer spectroscopy. Nanocomposites were synthesized in the temperature range of T
= 300-800 °C. It was shown that the samples synthesized at T = 300 °C contains of superparamagnetic nanoparticles
of magnetite and amorphous oxide of iron only. The process of forming nanoparticles of alloy
FeCo occurs within the temperature range 500-600 ° C due to the recovery of amorphous iron oxide and
magnetite as well as them dissolving in a phase of cobalt. The growth of size of nanoparticles of alloy by
agglomeration and dissolution of iron in the alloy nanoparticles occurs only at the temperature range of
synthesis 600-800 ° C. This is confirmed by a decrease of the content of Fe, which associated with carbon
and it is consistent with the results of phase and structural studies, carried out in previous works
THE STUDY OF PHASE COMPOSITION OF HIGHLY COERCISE ALLOYS WITH Fe-Ni-Al-CO-Ti AS THE BASE BY MEANS OF γ-RESONANCE SPECTROSCOPY
No abstract availabl
Magnetic Microstructure Aluminum-substituted Barium Hexaferrite for Microwave Devices mm-Wavelength Range
The magnetic structure and cationic distribution was investigate in ferrite with a hexagonal structure BaFe12 – хAlхO12 (х ≤ 2). It is found that when х = 2 Al3+ ions are localized mainly in the positions of 12k (а-sublattice) and 4f1 (с-sublattice). This contribute to change of number magnetically active connections and therefore the magnetic structure of ferrite and magnetic parameters. It was concluded about the possibility of using the results obtained with the choice of optimal composition of substrates for millimeter-wave devices