Structure-phase transformations in the Be–Fe–Be layered system subjected to irradiation and thermal treatment

Кадыржанов, К. К.; Vereshchak, M. F.; Manakova, I. A.; Ozernoy, A. N.; Rusakov, V. S.

doi:10.1016/j.jpcs.2013.03.002

Cited by 10 publications

(7 citation statements)

References 8 publications

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“…If excess Fe is present, then FeBe 2 will be the predominant intermetallic phase observed in the alloy. This is supported by recent experimental observations by Kadyrzhanov et al [52]. To quantify the driving force for the formation of FeBe 2 , in the presence of excess Fe,…”

Section: Stability Of the Intermetallic Phasessupporting

confidence: 73%

Crystal structure, thermodynamics, magnetics and disorder properties of Be–Fe–Al intermetallics

Burr

Middleburgh

Grimes

2015

Journal of Alloys and Compounds

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The elastic and magnetic properties, thermodynamical stability, deviation from stoichiometry and order/disorder transformations of phases that are relevant to Be alloys were investigated using density functional theory simulations coupled with phonon density of states calculations to capture temperature effects. A novel structure and composition were identified for the Be-Fe binary ε phase. In absence of Al, FeBe 5 is predicted to form at equilibrium above ∼1100 K, while the ε phase is stable only below ∼1500 K, and FeBe 2 is stable at all temperatures below melting. Small additions of Al are found to stabilise FeBe 5 over FeBe 2 and ε, while at high Al content, AlFeBe 4 is predicted to form. Deviations from stoichiometric compositions are also considered and found to be important in the case of FeBe 5 and ε. The propensity for disordered vs ordered structures is also important for AlFeBe 4 (which exhibits complete Al-Fe disordered at all temperatures) and FeBe 5 (which exhibits an order-disorder transition at ∼950 K).

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Section: Stability Of the Intermetallic Phasessupporting

confidence: 73%

Crystal structure, thermodynamics, magnetics and disorder properties of Be–Fe–Al intermetallics

Burr

Middleburgh

Grimes

2015

Journal of Alloys and Compounds

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“…The Mössbauer core serves as probe in a solid state. It can be used to study the dynamic properties; structural, valence, and charge states of the Mössbauer atom; the phase composition; and the atomic, crystalline, magnetic, and electronic features of the structure of the studied substance [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. Separation into magnetic and non-magnetic components makes it possible to facilitate the analysis of the chemical and phase state of iron in individual fractions of fly ashes, which is enriched by separation [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Mössbauer Studies of Narrow Fractions of Fly Ash Formed after Combustion of Ekibastuz Coal

et al. 2021

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Nuclear gamma-resonance spectroscopy on 57Fe nuclei, X-ray diffraction, and scanning electron microscopy have been used to study the narrow fractions of fly ash formed after combustion of the Ekibastuz coal. Two groups of samples of magnetic (ferrospheres) and non-magnetic type have been separated by granulometric and magnetic separation. A number of regularities associated with the granules size of fly ash have been established. According to the data of Mössbauer spectroscopy, a decrease in the magnetically ordered contribution has been identified with the growth of the particle size. After magnetic separation, iron in ferrospheres was found mainly in the structure of Fe3O4/γ-Fe2O3 and α-Fe2O3. The dominant phase was Fe3O4 (60–77%), the amount of which decreases with the growth of the grain size. With the growth of the particle size, the ratio of [Fe]tetra/[Fe]octa positions occupancy in Fe3O4 approaches 0.5; the structure of magnetite tends to the stoichiometric composition. α-Fe was found in the composition of ferrospheres, and a mechanism of its formation was proposed. The main components of the non-magnetic fractions of fly ash are mullite, hercynite, and silicate glass.

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“…Mössbauer spectroscopy at 57 Fe nuclei is the best method for detecting the iron-containing compounds and determination of the chemical state, electronic and magnetic structure of iron in them [18][19][20][21]. The MS spectrum of the Ekibastuz coal sample consists of two doublets (Figure 1).…”

Section: Mössbauer Spectroscopymentioning

confidence: 99%

Mössbauer and X-ray Studies of Phase Composition of Fly Ashes Formed after Combustion of Ekibastuz Coal (Kazakhstan)

Shokanov

Vereshchak

Manakova

2020

Metals

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Mössbauer spectroscopy and X-ray diffraction have been used to study samples of fly ashes formed after combustion of coal from the Ekibastuz basin at the thermal power plants TPP-2 and TPP-3 in Almaty (Kazakhstan). It has been established that the fractions of fly ashes contain iron in the form of magnetite Fe3O4 and hematite α-Fe2O3. The mixed valence of iron Fe3+ ↔ Fe2+ in the octahedral sublattice of magnetite is destroyed by isostructural substitution impurities. Maghemite γ-Fe2O3 is additionally present in the fly ash of TPP-3 as a product of magnetite slow oxidation. It was shown that at T ≥ 1400 °C the proportion of magnetite in fly ashes increases due to decomposition of hematite, maghemite, hercynite and the drop of iron content in mullite. It was concluded that the amount of iron in magnetite is a temperature indicator of fly ashes formation. The parameters of hyperfine interactions have been determined in the iron-containing minerals of fly ashes. It was identified that formation of the fly ashes structure occurs in oxidizing atmosphere, since no traces were revealed of reducing environment effect on the phase composition.

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Structure-phase transformations in the Be–Fe–Be layered system subjected to irradiation and thermal treatment

Cited by 10 publications

References 8 publications

Crystal structure, thermodynamics, magnetics and disorder properties of Be–Fe–Al intermetallics

Crystal structure, thermodynamics, magnetics and disorder properties of Be–Fe–Al intermetallics

Mössbauer Studies of Narrow Fractions of Fly Ash Formed after Combustion of Ekibastuz Coal

Mössbauer and X-ray Studies of Phase Composition of Fly Ashes Formed after Combustion of Ekibastuz Coal (Kazakhstan)

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