Synthesis of Na-bearing majorte in the system Mg3Al2Si3O12 -Na2MgSi5O12 at 11-20 GPa: solid solutions and structural features

2011 ◽  
Vol 3 (Special Issue) ◽  
pp. 1-7
Author(s):  
A. M. Dymshits ◽  
A. V. Bobrov ◽  
L. Bindi ◽  
K. D. Litasov ◽  
A. F. Shatskiy ◽  
...  
Keyword(s):  
Solid Solutions ◽  
Structural Features

scholarly journals Crystallochemical Design of Huntite-Family Compounds

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 100 ◽  
Author(s):  
Galina Kuz’micheva ◽  
Irina Kaurova ◽  
Victor Rybakov ◽  
Vadim Podbel’skiy
Keyword(s):  
Rare Earth ◽  
Solid Solutions ◽  
Materials Science ◽  
Structural Features ◽  
Effective Option ◽  
Space Symmetry ◽  
Diffraction Patterns ◽  
Real Composition ◽  
The Rare Earth

Huntite-family nominally-pure and activated/co-activated LnM3(BO3)4 (Ln = La–Lu, Y; M = Al, Fe, Cr, Ga, Sc) compounds and their-based solid solutions are promising materials for lasers, nonlinear optics, spintronics, and photonics, which are characterized by multifunctional properties depending on a composition and crystal structure. The purpose of the work is to establish stability regions for the rare-earth orthoborates in crystallochemical coordinates (sizes of Ln and M ions) based on their real compositions and space symmetry depending on thermodynamic, kinetic, and crystallochemical factors. The use of diffraction structural techniques to study single crystals with a detailed analysis of diffraction patterns, refinement of crystallographic site occupancies (real composition), and determination of structure–composition correlations is the most efficient and effective option to achieve the purpose. This approach is applied and shown primarily for the rare-earth scandium borates having interesting structural features compared with the other orthoborates. Visualization of structures allowed to establish features of formation of phases with different compositions, to classify and systematize huntite-family compounds using crystallochemical concepts (structure and superstructure, ordering and disordering, isostructural and isotype compounds) and phenomena (isomorphism, morphotropism, polymorphism, polytypism). Particular attention is paid to methods and conditions for crystal growth, affecting a crystal real composition and symmetry. A critical analysis of literature data made it possible to formulate unsolved problems in materials science of rare-earth orthoborates, mainly scandium borates, which are distinguished by an ability to form internal and substitutional (Ln and Sc atoms), unlimited and limited solid solutions depending on the geometric factor.

Thermal Stability of Rapidly Solidified Alloys of Aluminium with Transition Metals

2006 ◽  
Vol 519-521 ◽  
pp. 389-394 ◽  
Author(s):  
Dalibor Vojtěch ◽  
Jan Verner ◽  
Barbora Bártová ◽  
Karel Saksl
Keyword(s):  
Thermal Stability ◽  
Transition Metals ◽  
Solid Solutions ◽  
Melt Spinning ◽  
Structural Features ◽  
High Thermal Stability ◽  
Crystalline Phases ◽  
Supersaturated Solid Solutions ◽  
Rapidly Solidified ◽  
Thermal Stability Of

Rapidly solidified (RS) Al-TM (TM = transition metal) alloys are perspective materials from scientific, as well as technological point of view. Generally, they are produced by the melt atomization or by the melt spinning. Subsequent compaction is commonly performed by the hot extrusion. Since transition metals, such as Cr, Fe, Ni, Zr, Ti, Mn and others, have low diffusion coefficients in solid aluminium (lower by several orders of magnitude than those of common alloying elements like Cu, Si, Mg, Zn etc.) the RS Al-TM alloys are characterized by a high thermal stability. In this paper, several RS Al-TM (TM = Cr, Fe, Ti, Mn, Ni) alloys prepared by the melt spinning and melt atomization are compared to commercially available 2xxx, 6xxx and 7xxx wrought alloys. The main structural features of both RS and wrought alloys are described. The RS alloys are characterized by the presence of micro and nano-scale crystalline and/or quasi-crystalline phases and supersaturated solid solutions. The elevated-temperature behaviour is compared for both groups of materials. The thermal stability of the investigated materials is determined by room temperature hardness measurements after various annealing regimes and a high thermal stability of the RS alloys is demonstrated. The microstructural changes and phase transformations occurring in the investigated materials upon heating are described. In the Al-TM alloys, very slow decomposition of the supersaturated solid solutions, precipitation and decomposition of the metastable quasi-crystalline phases occur.

Structural features of the formation of La1−x Ca x FeO3−δ (0 ≤x ≤ 0.7) hetero valent solid solutions

2010 ◽  
Vol 51 (5) ◽  
pp. 891-897 ◽  
Author(s):  
A. N. Nadeev ◽  
S. V. Tsybulya ◽  
E. Yu. Gerasimov ◽  
N. A. Kulikovskaya ◽  
L. A. Isupova
Keyword(s):  
Solid Solutions ◽  
Structural Features

scholarly journals The key role of the composition and structural features in fluoride ion conductivity in tysonite Ce1−xSrxF3−x solid solutions

2017 ◽  
Vol 46 (11) ◽  
pp. 3761-3769 ◽  
Author(s):  
Belto Dieudonné ◽  
Johann Chable ◽  
Monique Body ◽  
Christophe Legein ◽  
Etienne Durand ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Solid Solutions ◽  
Structural Features ◽  
Ion Conductivity ◽  
Fluoride Ion

Evolution with x of RT ionic conductivity of RE1−xAExF3−x showing that Ce1−xSrxF3−x is the best F− tysonite conductor is discussed.

Superconducting Properties and Structural Features of Solid Solutions on the Base of Barium-Samarium Cuprate

2009 ◽  
Vol 4 (1) ◽  
pp. 68-74
Author(s):  
Aleksandr Blinov ◽  
Margarita Kameneva ◽  
Ludmila Kozeeva
Keyword(s):  
Solid Solution ◽  
Solid Solutions ◽  
Single Phase ◽  
Structural Features ◽  
Vortex Pinning ◽  
Superconducting Properties ◽  
Pinning Centers

Superconducting properties, structural and microstructural features of single-phase polycrystalline samples of bariumsamarium cuprate and solid solution on the base of Sm1+xBa2–xCu3O6+y (123SmSS) with х = 0.0–0.7 prepared in air were studied. It was shown that the solid solution decomposes at 0.12 < х < 0.3 by the spinodal mechanism to form layered microstructures with a variable Sm/Ba ratio. The data obtained are useful for understanding the mechanisms of the formation of possible vortex pinning centers in Ln1+xBa2–xCu3O6+у phases with «light» Ln.

Mechanical Alloying Synthesis of K2Bi8Se13– type Solid Solutions

2007 ◽  
Vol 1044 ◽  
Author(s):  
Nikolaos Toumpas ◽  
Theodora Kyratsi ◽  
Euripides Hatzikraniotis ◽  
Andreas Tsiappos ◽  
Eleni Pavlidou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Scanning Electron Microscopy ◽  
Electrical Properties ◽  
Mechanical Alloying ◽  
Solid Solutions ◽  
Structural Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

AbstractSolid solutions of β-K2Bi8-xSbxSe13are an interesting series of materials for thermoelectric investigations due to their very low thermal conductivity and highly anisotropic electrical properties. In this work, we aimed to synthesize solid solutions of β-K2Bi8-xSbxSe13type materials using powder techniques. The synthesis was based on mechanical alloying as well as sintering procedures. The products were studied in terms of structural features, composition and purity with powder x-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Preliminary results on thermoelectric properties as well as IR reflectivity measurements are presented.

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