Особенности спектральных характеристик различных структурных модификаций Lu-=SUB=-1-x-=/SUB=-RE-=SUB=-x-=/SUB=-BO-=SUB=-3-=/SUB=-

The structure, IR absorption and luminescence spectra of the microcrystals of Lu1-xEuxBO3, Lu0.99-xTbxEu0.01BO3, and Lu0.99−xYxEu0.01BO3 orthoborates (0 ≤ x ≤ 0.25) synthesized at 970°С were studied. An increase in х leads to a sequential change of the structural state of the orthoborates. At х ≤ 0.07 – 0.09, the compounds form a solid solution with the calcite structure and microcrystal size of 8 – 20 µm. Then, they become two-phase: the vaterite phase arises along with the calcite structure. At х ≥ 0.2 – 0.25, the entire bulk of a sample has the vaterite structure. A correspondence between the structure and spectral characteristics of these compounds was established. Luminescence spectra were investigated at different wavelengths of exciting light. This allowed obtaining information on the structure of a near-surface layer and the bulk of microcrystals of the investigated samples. It is shown that the vaterite phase arises both in the bulk of large microsrystals (8 – 20 µm) and in the form of small microsrystals (1 – 2 µm).

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Эволюция спектральных и структурных характеристик ортоборатов La-=SUB=-0.98-x-=/SUB=-Lu-=SUB=-x-=/SUB=-Eu-=SUB=-0.02-=/SUB=-BO-=SUB=-3-=/SUB=-

Физика твердого тела ◽

10.21883/ftt.2021.12.51677.172 ◽

2021 ◽

Vol 63 (12) ◽

pp. 2142

Author(s):

С.З. Шмурак ◽

В.В. Кедров ◽

А.П. Киселев ◽

Т.Н. Фурсова ◽

И.И. Зверькова ◽

...

Keyword(s):

Surface Layer ◽

Structural State ◽

Spectral Characteristics ◽

Luminescence Spectra ◽

Exciting Light ◽

Ir Absorption ◽

Excitation Spectra ◽

Two Phase ◽

Near Surface ◽

Sequential Change

The structure, IR absorption, luminescence, and luminescence excitation spectra of La0.98xLuxEu0.02 BO3 orthoborates synthesized at 970°C were studied at 0 ≤ x ≤ 0.98. An increase in х leads to a sequential change of the structural state of the orthoborates. At first, the compound has the aragonite structure. Then, it becomes two-phase and contains the aragonite and vaterite phases. With a further increase in х, the compounds have the vaterite structure, then the vaterite and calcite structure, and, finally, the calcite structure. Correspondence between the structure and spectral characteristics of these compounds was established. Luminescence spectra were investigated at different wavelengths of exciting light. This allowed obtaining information on the structure of a near-surface layer and the bulk of microcrystals of the investigated samples. It is shown that the vaterite phase arises in the bulk of microcrystals of samples that have the aragonite structure.

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Влияние индия на спектральные и структурные характеристики Lu-=SUB=-0.98-x-=/SUB=-In-=SUB=-x-=/SUB=-Eu-=SUB=-0.02-=/SUB=-BO-=SUB=-3-=/SUB=-

Физика твердого тела ◽

10.21883/ftt.2020.12.50215.162 ◽

2020 ◽

Vol 62 (12) ◽

pp. 2110

Author(s):

С.З. Шмурак ◽

В.В. Кедров ◽

А.П. Киселев ◽

Т.Н. Фурсова ◽

И.И. Зверькова

Keyword(s):

Structural Modification ◽

Sample Volume ◽

Structural Transformations ◽

Ion Concentration ◽

Luminescence Spectra ◽

Ir Absorption ◽

Surface Layers ◽

Near Surface ◽

Structural Modifications ◽

Absorption And Luminescence Spectra

The structure and the IR absorption and luminescence spectra of the Lu0.98-хInхEu0.02BO3 orthoborates are studied at 0 ≤ x ≤ 0.1. The Lu1-xInxBO3 solid solution, which consists of lutetium borate LuBO3 having two stable structural modifications (calcite, vaterite) and indium orthoborate InBO3 having one structural modification (calcite), crystallizes at x = 0.1 to form a calcite structure almost throughout the volume. We showed that the structural transformations in the Lu0.98-хInхEu0.02BO3 orthoborates induced by an increase in the In3+ ion concentration begin in the near-surface layers of the orthoborate microcrystals. The amount of calcite increases in the sample volume with x, and calcite occupies 98% of the Lu0.88In0.1Eu0.02BO3 sample volume.

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Влияние церия на спектральные и структурные характеристики LuBO-=SUB=-3-=/SUB=-(Ce, Tb)

Физика твердого тела ◽

10.21883/ftt.2020.11.50067.047 ◽

2020 ◽

Vol 62 (11) ◽

pp. 1888

Author(s):

С.З. Шмурак ◽

В.В. Кедров ◽

А.П. Киселев ◽

Т.Н. Фурсова ◽

И.И. Зверькова ◽

...

Keyword(s):

Solid Solution ◽

Rare Earth ◽

Solid Solutions ◽

Structural State ◽

Optically Active ◽

Phase Fraction ◽

Ir Absorption ◽

Excitation Spectra ◽

Two Phase ◽

Structure Sensitive

The structure, IR absorption, luminescence and luminescence excitation spectra of Ce3+ and Tb3+ ions have been studied in the crystals of Lu1−x−yCexTbyBO3 solid solutions at 0 ≤ x ≤ 0.01, 0.07 ≤ y ≤ 0.16. It has been shown that Lu1−yTbyBO3 solid solution synthesized at Т = 970°С has the structure of a calcite at 0  y ≤ 0.07, the structure of a vaterite at y ≥ 0.16, and is two-phase in a range of 0.07  y < 0.16. It has been determined that additional alloying of two-phase Lu1-yTbyBO3 samples with the vaterite phase fraction of not more than ~ 20 % with 0.5 – 1 at.% of Ce3+ leads to a significant decrease in the amount of the vaterite phase. It has been demonstrated that Ce3+ ions can be used as structure-sensitive and optically active marks when analyzing the structural state of rare earth orthoborates.

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Спектральные и структурные характеристики вольфраматов (Lu-=SUB=-1-x-=/SUB=-Eu-=SUB=-x-=/SUB=-)-=SUB=-2-=/SUB=-(WO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-

Физика твердого тела ◽

10.21883/ftt.2019.11.48420.516 ◽

2019 ◽

Vol 61 (11) ◽

pp. 2142

Author(s):

С.З. Шмурак ◽

В.В. Кедров ◽

А.П. Киселев ◽

Т.Н. Фурсова ◽

И.И. Зверькова ◽

...

Keyword(s):

Solid Solutions ◽

Structural Characteristics ◽

Spectral Characteristics ◽

Orthorhombic Phase ◽

Luminescence Spectra ◽

Ir Absorption ◽

Space Group ◽

Wetting Ability ◽

Ir Absorption Spectra ◽

Wide Range

Investigated are the structure, luminescence, and IR absorption spectra of (Lu1−xEux)2(WO4)3 solid solutions in a wide range of Eu concentrations (0 ≤ x ≤ 1). A sequential replacement of two types of crystalline phases occurs with an increase in Eu concentration. The orthorhombic phase (Pbcn space group) of tungstate solid solutions is observed at 0 ≤ x < 0.5. A monoclinic phase (C2/c space group) arises along with the orthorhombic one in the range of 0.5 ≤ x ≤ 0.8, while at x > 0.8, the solid solution has a monoclinic structure. The correspondence between the structure and spectral characteristics of these compounds is established. A change in the structural state results in a change in luminescence spectra, as well as in the spectra of luminescence excitation of tungstates. The isotherm of water adsorption by the tungstate samples and its effect on their spectral and structural characteristics are studied in view of the wetting ability of (Lu1−xEux)2(WO4)3 solid solutions. It is established that the maximum luminescence under the resonant excitation of Eu3+ ions is observed in the samples with a monoclinic C2/c structure at x ~0.9.

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Investigation of the processes of the formation of a nonequilibrium phase-structural state in FeTiB films obtained by magnetron sputtering

Izvestiya Vuzov Poroshkovaya Metallurgiya i Funktsional’nye Pokrytiya (Universitiesʹ Proceedings Powder Metallurgy аnd Functional Coatings) ◽

10.17073/1997-308x-2020-3-65-75 ◽

2020 ◽

pp. 65-75

Author(s):

E. N. Sheftel ◽

V. A. Tedzhetov ◽

Ph. V. Kiryukhantsev-Korneev ◽

E. V. Harin ◽

G. Sh. Usmanova ◽

...

Keyword(s):

Solid Solution ◽

Grain Size ◽

Phase Composition ◽

Magnetron Sputtering ◽

Amorphous Phase ◽

Structural State ◽

Materials Science ◽

Reasonable Assumption ◽

Two Phase ◽

Efficient Operation

The main trends of modern developing magnetic microelectronics are miniaturization and speed, while ensuring efficient operation in the MHz and GHz frequency ranges of magnetic fields. Developing new magnetic materials featured by properties that ensure the implementation of these trends is the key fundamental and applied problem of materials science. In this regard, Fe-Me-X nanocrystalline soft magnetic alloys (Me is one of the metals from Group IVb of the Periodic Table, X is one of the N, C, O, B light elements) obtained in the form of films are of interest. As shown earlier by the authors of this article on Fe-Zr-N films, such films featuring by the Fe/MeX two-phase structure can provide a combination of high saturation induction (Bs), low coercive force (Hc), high hardness, and thermal stability of the structure. The films were produced by magnetron sputtering. The data obtained and published by the authors on the Fe–Ti–B films earlier indicate great prospects for their application in modern microelectronics. There are no any other published results of FeTiB film studies in the context of microelectronics applications. In this paper, we continue the studies of FeTiB films started earlier to identify the chemical and phase composition providing the level of properties required for film application in microelectronics. Nanocrystalline films containing 0 to 14.3 at.% Ti and 0 to 28.9 at.% B were obtained by DC magnetron sputtering. The phase-structural state of the films was studied by X-ray diffraction and transmission electron microscopy. All films are divided into 3 groups according to phase composition: single-phase (supersaturated solid solution of Ti in α-Fe), two-phase (α-Fe(Ti)/α-Ti, α-Fe(Ti)/TiB2, α-Fe (Ti)/FeTi, α-Fe(Ti)/Fe2B) and XRD amorphous. It is shown that XRD amorphous films feature by a mixed structure represented by a solid solution of α-Fe(Ti) with a grain size between 0.7 and 2 nm and an amorphous phase. A reasonable assumption is made on the amorphous phase enrichment by boron. A quantitative assessment of the α-Fe(Ti) phase grain size and its dependence on the chemical and phase composition of the films is given. The mechanisms of solid solution and dispersion hardening determine the grain size of this phase.

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Bcc / B2 phase equilibria and phase transformation from B2 to β’ in refractory Nb-X(Pd, Rh, Ir)-Al

MRS Advances ◽

10.1557/adv.2017.60 ◽

2017 ◽

Vol 2 (25) ◽

pp. 1335-1340

Author(s):

T. Yamanouchi ◽

S. Miura ◽

M. Ohno ◽

K. Ikeda

Keyword(s):

Solid Solution ◽

Phase Transformation ◽

Surface Layer ◽

Phase Field ◽

Composition Range ◽

Eutectic Temperature ◽

Two Phase ◽

Wide Composition Range ◽

B2 Phase ◽

Bcc Phase

ABSTRACTFor the improvement of oxidation resistance of Nb-based alloys, PdAl-B2 is expected as Al reservoir for Al2O3 surface layer because it is in equilibrium with Nbss (bcc) phase. However, PdAl forms cracks during casting caused by B2 -> β’ transformation. To suppress B2 -> β’ transformation, Rh, Ru and Ir were chosen as additive elements. It is found that bcc / B2 two-phase field in Nb-Pd-Ir-Al system is limited to be small fraction of Ir, while (Pd,Rh)Al-B2 is in equilibrium with bcc solid solution in a wide composition range and addition of Rh prevents occurrence of B2 -> β’ transformation. Composition range of (Pd,Ru)Al-B2 in equilibrium with bcc phase is wider than (Pd,Ir)Al-B2 but narrower than (Pd,Rh)Al-B2. Rh and Ru addition are also beneficial for improving eutectic temperature of Nb-bcc / B2 aluminide two-phase alloys.

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Shock consolidation of Ni-Ti alloy powder

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143730 ◽

1986 ◽

Vol 44 ◽

pp. 430-431

Author(s):

Naresh N. Thadhani ◽

Thad Vreeland ◽

Thomas J. Ahrens

Keyword(s):

Alloy Powder ◽

Amorphous Material ◽

Ti Alloy ◽

Two Phase ◽

Near Surface ◽

Optical Micrograph ◽

Shock Compaction ◽

Powder Particles ◽

Ti Powder ◽

Rapidly Solidified

A spherically-shaped, microcrystalline Ni-Ti alloy powder having fairly nonhomogeneous particle size distribution and chemical composition was consolidated with shock input energy of 316 kJ/kg. In the process of consolidation, shock energy is preferentially input at particle surfaces, resulting in melting of near-surface material and interparticle welding. The Ni-Ti powder particles were 2-60 μm in diameter (Fig. 1). About 30-40% of the powder particles were Ni-65wt% and balance were Ni-45wt%Ti (estimated by EMPA).Upon shock compaction, the two phase Ni-Ti powder particles were bonded together by the interparticle melt which rapidly solidified, usually to amorphous material. Fig. 2 is an optical micrograph (in plane of shock) of the consolidated Ni-Ti alloy powder, showing the particles with different etching contrast.

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Transition alpha structure in beta-isomorphous Nb-Hf alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126068 ◽

1987 ◽

Vol 45 ◽

pp. 232-233

Author(s):

R.W. Carpenter ◽

Changhai Li ◽

David J. Smith

Keyword(s):

Solid Solution ◽

Solution Phase ◽

Miscibility Gap ◽

Large Strains ◽

Solid Solution Phase ◽

Two Phase ◽

Diffuse Intensity ◽

Metastable Form ◽

The Matrix ◽

Equilibrium Morphology

Binary Nb-Hf alloys exhibit a wide bcc solid solution phase field at temperatures above the Hfα→ß transition (2023K) and a two phase bcc+hcp field at lower temperatures. The β solvus exhibits a small slope above about 1500K, suggesting the possible existence of a miscibility gap. An earlier investigation showed that two morphological forms of precipitate occur during the bcc→hcp transformation. The equilibrium morphology is rod-type with axes along <113> bcc. The crystallographic habit of the rod precipitate follows the Burgers relations: {110}||{0001}, <112> || <1010>. The earlier metastable form, transition α, occurs as thin discs with {100} habit. The {100} discs induce large strains in the matrix. Selected area diffraction examination of regions ∼2 microns in diameter containing many disc precipitates showed that, a diffuse intensity distribution whose symmetry resembled the distribution of equilibrium α Bragg spots was associated with the disc precipitate.

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