scholarly journals Ceramic synthesis of disordered lithium rich oxyfluoride materials

2020 ◽  
Vol 467 ◽  
pp. 228230
Author(s):  
Jean-Marcel Ateba Mba ◽  
Iztok Arčon ◽  
Gregor Mali ◽  
Elena Tchernychova ◽  
Ralf Witte ◽  
...  
Keyword(s):  
Ceramic Synthesis

Under Pressure: Mechanochemical Effects on Structure and Ion Conduction in the Sodium-Ion Solid Electrolyte Na3PS4

2020 ◽  
Author(s):  
Theodosios Famprikis ◽  
O. Ulas Kudu ◽  
James Dawson ◽  
Pieremanuele Canepa ◽  
François Fauth ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Mechanochemical Synthesis ◽  
Activation Volume ◽  
External Pressure ◽  
Sodium Ion ◽  
Variable Pressure ◽  
Ion Conductor ◽  
Ceramic Synthesis ◽  
Solid State Batteries ◽  
Fast Ion

<div> <p>Fast-ion conductors are critical to the development of solid-state batteries. The effects of mechanochemical synthesis that lead to increased ionic conductivity in an archetypical sodium-ion conductor Na<sub>3</sub>PS<sub>4</sub> are not fully understood. We present here a comprehensive analysis based on diffraction (Bragg, pair distribution function), spectroscopy (impedance, Raman, NMR, INS) and <i>ab-initio</i> simulations aimed at elucidating the synthesis-property relationships in Na<sub>3</sub>PS<sub>4</sub>. We consolidate previously reported interpretations about the local structure of ball-milled samples, underlining the sodium disorder and showing that a local tetragonal framework more accurately describes the structure than the originally proposed cubic one. Through variable-pressure impedance spectroscopy measurements, we report for the first time the activation volume for Na<sup>+</sup> migration in Na<sub>3</sub>PS<sub>4</sub>, which is ~30% higher for the ball-milled samples. Moreover, we show that the effect of ball-milling on increasing the ionic conductivity of Na<sub>3</sub>PS<sub>4</sub> to ~10<sup>-4</sup> S/cm can be reproduced by applying external pressure on a sample from conventional high temperature ceramic synthesis. We conclude that the key effects of mechanochemical synthesis on the properties of solid electrolytes can be analyzed and understood in terms of pressure, strain and activation volume.</p> </div>

New route for synthesis of Synroc-like ceramic using non-selective sorbent LHT-9

MRS Advances ◽  
2018 ◽  
Vol 3 (20) ◽  
pp. 1111-1116 ◽  
Author(s):  
B.Yu. Zubekhina ◽  
B.E. Burakov ◽  
Yu.Yu. Petrov ◽  
S.N. Britvin ◽  
V.F. Mararitsa ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Chemical Durability ◽  
Bulk Liquid ◽  
Distilled Water ◽  
Selective Sorbent ◽  
Ceramic Synthesis ◽  
Multi Stage ◽  
High Level ◽  
Radionuclide Incorporation ◽  
Titanate Ceramic

ABSTRACT:Immobilization of bulk liquid high level radioactive waste (HLW) in Synroc ceramic is well-known reliable way for final isolation of dangerous long-lived radionuclides from biosphere. The alternative method of Synroc-like ceramic synthesis has been proposed. Radionuclide incorporation into crystalline titanate host-phases can be provided as a result of direct radionuclide sorption from liquid HLW using non-selective sorbent – layered hydrazinium titanate (LHT-9). Such an approach allows excluding expensive multi-stage procedure of precursor preparation. The precipitate obtained after sorption can be easily transformed into Synroc-like ceramic by cold pressing followed with sintering in air at 1000-1200°C. The highly radioactive samples of titanate ceramic loaded with real HLW have been synthesized and preliminary studied at KRI hot-cell facility. Chemical durability of this sample has been studied using static leach test in distilled water at 90°C and the leach rates for 154Eu, 241Am, 244Cm were (in g·m-2·day-1) from 2·10-4 to 5·10-3. Normalised 137Cs mass loss was 0.3 g·m-2 for 110 days at the same conditions.

Structure and properties of solid solutions in the Mg-Al-B system

Open Physics ◽  
2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Ludmila Sevastyanova ◽  
Olga Gulish ◽  
Vladimir Stupnikov ◽  
Vladimir Genchel ◽  
Oleg Kravchenko ◽  
...  
Keyword(s):  
Solid Solutions ◽  
Unit Cell ◽  
Superconducting Transition ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Resistivity Measurements ◽  
Ceramic Synthesis

AbstractCompounds with the general formula Mg1−x AlxB2 were obtained by two-step ceramic synthesis. All compounds were characterized by X-ray diffraction, NMR spectroscopy, and by four point probe resistivity measurements in various magnetic fields method. The diborides unit cell parameters were determined as a function of the Al mole fraction. With the vaues of x up to 0.40 (where x is the composition of the stock prepared for sintering), the unit cell parameters of Mg1−x AlxB2 are similar to those of pure MgB2 and the superconducting transition temperature was lowered. For stock compositions of 0:25 ≤ x ≤ 0:60, the products contain a superstructure, also superconducting phase, which becomes the only product at x = 0:50, and at x > 0:60 this phase is replaced by AlB2-based solid solutions.

scholarly journals Selective metathesis synthesis of MgCr2S4 by control of thermodynamic driving forces

2020 ◽  
Vol 7 (5) ◽  
pp. 1310-1316 ◽  
Author(s):  
Akira Miura ◽  
Hiroaki Ito ◽  
Christopher J. Bartel ◽  
Wenhao Sun ◽  
Nataly Carolina Rosero-Navarro ◽  
...  
Keyword(s):  
Cathode Material ◽  
Driving Forces ◽  
Selective Synthesis ◽  
Ceramic Synthesis ◽  
Synthesis Routes

By altering the thermodynamic landscape, metathesis enables the rapid and selective synthesis of MgCr2S4 thiospinel, a compelling Mg-cathode material that is laborious to make via traditional ceramic synthesis routes.

Inorganic matrices for immobilization of Tc-99

2009 ◽  
Vol 1193 ◽  
Author(s):  
Yulia I. Korneyko ◽  
Vladimir M. Garbuzov ◽  
Olga V. Schmidta ◽  
Boris E. Burakov
Keyword(s):  
Metallic Phase ◽  
Inert Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Mn Oxide ◽  
Ceramic Synthesis ◽  
Reducing Conditions ◽  
Metallic Inclusions ◽  
Inorganic Matrices

AbstractImmobilization of long-lived 99Tc requires development of chemically resistant inorganic matrices. Samples of ceramics based on crystalline Fe-Mn- and Zr-Mn-oxide compounds were synthesized at 1150°C in air, reducing or inert atmosphere from precursors doped with 5-12 wt.% Tc. All the samples obtained were studied using optical and scanning electron microscopy (SEM); powder X-ray diffraction (XRD) and microprobe analysis (EMPA). Content of Tc varied from 0.5-0.8 to 3-6 wt.% in oxide host phases and from 54 to 93 wt.% in metallic inclusions. It was demonstrated that synthesis of oxide host-phases under oxidizing or reducing conditions was not optimal due to partial Tc volatilization or metallic phase formation, respectively. The use of inert atmosphere for ceramic synthesis supports Tc incorporation into crystalline structure of stable host-phases. Development of optimal methods of precursor preparation and synthesis conditions of Tc-doped ceramic are being discussed.

Research on Correlation between Formula of Steel Slag Ceramic (CaO-MgO-Al2O3-SiO2 System) and Macro Property

2011 ◽  
Vol 374-377 ◽  
pp. 1220-1225
Author(s):  
Li Hua Zhao ◽  
Wei Wei ◽  
Chao Lian ◽  
Xian Cong Zhao ◽  
Hao Bai ◽  
...  
Keyword(s):  
Bending Strength ◽  
Converter Slag ◽  
Steel Slag ◽  
Raw Material ◽  
National Standard ◽  
New Approach ◽  
Ceramic Synthesis ◽  
All Ceramic ◽  
System Phase Diagram ◽  
Xrd Patterns

This paper demonstrated a new approach to the utilization of steel slag and provided a pattern for steel slag ceramic synthesis. Based on previous research on steel slag (converter slag) applied as raw material of ceramic and directed at content of steel slag CaO-MgO-Al2O3(5wt%)-SiO2 system phase diagram was utilized in steel slag ceramic formula designing and augite region was selected. Bending strength of sample could reach 62.26MPa which was higher than national standard. When the content of steel slag was 40wt%, the steel slag ceramic would perform rather high bending strength. Through XRD patterns demonstrated the dominated crystal phases of all ceramic samples were pyroxene group crystals, akermanite existed in some samples also. But bending strengths of ceramics containing akermanite were lower than of samples containing pyroxene purely. Hence, diopside could be considered as the factor of improving ceramic bending strength.

Synthesis of Crystalline Ceramics for Actinide Immobilisation

2007 ◽  
Author(s):  
B. Burakov ◽  
V. Gribova ◽  
A. Kitsay ◽  
M. Ojovan ◽  
N. C. Hyatt ◽  
...  
Keyword(s):  
Hot Isostatic Pressing ◽  
Industrial Applications ◽  
Nuclear Industry ◽  
Synthesis Methods ◽  
Khlopin Radium Institute ◽  
Radium Institute ◽  
Joint Project ◽  
Ceramic Synthesis ◽  
The Matrix ◽  
Processing Plants

Methods for the synthesis of ceramic wasteforms for the immobilization of actinides are common to those for non-radioactive ceramics: hot uniaxial pressing (HUP); hot isostatic pressing (HIP); cold pressing followed by sintering; melting (for some specific ceramics, such as garnet/perovskite composites). Synthesis of ceramics doped with radionuclides is characterized with some important considerations: all the radionuclides should be incorporated into crystalline structure of durable host-phases in the form of solid solutions and no separate phases of radionuclides should be present in the matrix of final ceramic wasteform; all procedures of starting precursor preparation and ceramic synthesis should follow safety requirements of nuclear industry. Synthesis methods that avoid the use of very high temperatures and pressures and are easily accomplished within the environment of a glove-box or hot cell are preferable. Knowledge transfer between the V. G. Khlopin Radium Institute (KRI, Russia) and Immobilisation Science Laboratory (ISL, UK) was facilitated in the framework of a joint project supported by UK Royal Society. In order to introduce methods of precursor preparation and ceramic synthesis we selected well-known procedures readily deployable in radiochemical processing plants. We accounted that training should include main types of ceramic wasteforms which are currently discussed for industrial applications.

Precipitation of CoS vs Ceramic Synthesis for Improved Performance in Lithium Cells

2008 ◽  
Vol 155 (3) ◽  
pp. A189 ◽  
Author(s):  
J. L. Gómez-Cámer ◽  
F. Martin ◽  
J. Morales ◽  
L. Sánchez
Keyword(s):  
Ceramic Synthesis ◽  
Improved Performance ◽  
Lithium Cells
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