scholarly journals MASTERING THE PROCESSES OF SYNTHESIS OF OXIDE COMPOUNDS WITH THE USE OF A POWERFUL SOURCE OF FAST HEATING OF THE INITIAL INGREDIENTS

2021 ◽  
pp. 118-128
Author(s):  
Volodymyr Oleksiyovych Chyshkala ◽  
Serhii Volodymyrovych Lytovchenko ◽  
Edwin Spartakovych Gevorkyan ◽  
Volodymyr Pavlovych Nerubatskyi ◽  
Oksana Mykolaivna Morozova
Keyword(s):  
High Temperature ◽  
Nuclear Power ◽  
Materials Science ◽  
Tantalum Oxide ◽  
Pyrochlore Phase ◽  
Initial Mixture ◽  
Lattice Parameter ◽  
Plasma Electron ◽  
New Materials ◽  
Fast Heating

The creation of new materials with predetermined properties is perhaps the mostimportant issue and problem of modern materials science. Increasingly harsh conditions for the useof materials in modern, and especially - promising technological processes, the need to ensure andimplement the safest conditions for humanity and the environment of modern industrial production,the importance and increasing role of economic factors – all these factors necessitate improvingknown and creating new materials, as well as technologies for their production and use. Furthereconomically justified, socially attractive and technologically safe use of nuclear technologies andoperation of modern complex technical facilities, which undoubtedly include nuclear power devices,further development of nuclear and in the future thermonuclear energy is impossible withoutmodernization.The article implements the method of electron beam heating of a mixture of yttrium andzirconium oxides for the synthesis of complex oxides. The initial mixture contained ingredients in anamount corresponding to the compound Y2Zr2O7. The mixture was heated in a tantalum containeralmost to the melting point of tantalum (2915 C). The high temperature of the process is provided bythe use of a system with a plasma electron emitter. The purpose of the vacuum high-temperature effect on the powder mixture was to implement conditions sufficient to initiate reactions for the synthesis ofcomplex oxides. The analysis of the obtained samples recorded after the initial high-temperaturetreatment a fluorite-type phase (Y, Zr) Ox with a lattice parameter of 5.2 Å and technologicalimpurities of tantalum oxide. After additional annealing in air at 1200 C for 7 hours, another phasewith a lattice parameter of 5.17 Å was recorded, as well as impurities of tantalum oxide. The testedsynthesis conditions lead to the formation of multi-element oxides with a structure of only fluorite,pyrochlore phase in the heat is not detected.

Combinatorial Study of New Materials Sensing High Temperature

2010 ◽  
Vol 636-637 ◽  
pp. 295-300
Author(s):  
Ya Lin Lu ◽  
Karen A. Reinhardt
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Materials Science ◽  
Oxide Materials ◽  
New Materials ◽  
Suitable Host ◽  
Emission Lifetime ◽  
Remotely Sense ◽  
Rare Earth Doped ◽  
Combinatorial Strategy

Interests in finding new rare-earth doped oxide materials able to remotely sense high temperature have been intensifying in recent years. If applied, advanced combinatorial strategy for materials science should be efficient in finding a suitable host material, and in optimizing a rare earth ion’s doping concentration, luminescence intensity, emission lifetime, etc. This research demonstrates our preliminary effort to apply the advanced combinatorial material strategy to this new area of finding materials for sensing high temperatures.

High-Temperature Instability of A Cr2Nb-Nb(Cr) Microlaminate Composite

1996 ◽  
Vol 54 ◽  
pp. 374-375
Author(s):  
M. Larsen ◽  
R.G. Rowe ◽  
D.W. Skelly
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Aircraft Engine ◽  
Lattice Parameter ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Cross Sectional ◽  
Bcc Structure

Microlaminate composites consisting of alternating layers of a high temperature intermetallic compound for elevated temperature strength and a ductile refractory metal for toughening may have uses in aircraft engine turbines. Microstructural stability at elevated temperatures is a crucial requirement for these composites. A microlaminate composite consisting of alternating layers of Cr2Nb and Nb(Cr) was produced by vapor phase deposition. The stability of the layers at elevated temperatures was investigated by cross-sectional TEM.The as-deposited composite consists of layers of a Nb(Cr) solid solution with a composition in atomic percent of 91% Nb and 9% Cr. It has a bcc structure with highly elongated grains. Alternating with this Nb(Cr) layer is the Cr2Nb layer. However, this layer has deposited as a fine grain Cr(Nb) solid solution with a metastable bcc structure and a lattice parameter about half way between that of pure Nb and pure Cr. The atomic composition of this layer is 60% Cr and 40% Nb. The interface between the layers in the as-deposited condition appears very flat (figure 1). After a two hour, 1200 °C heat treatment, the metastable Cr(Nb) layer transforms to the Cr2Nb phase with the C15 cubic structure. Grain coarsening occurs in the Nb(Cr) layer and the interface between the layers roughen. The roughening of the interface is a prelude to an instability of the interface at higher heat treatment temperatures with perturbations of the Cr2Nb grains penetrating into the Nb(Cr) layer.

A review of high-power magnetoplasmodynamic electric propulsion designs and studies of RSC Energia

2020 ◽  
pp. 112-133
Author(s):  
Victor V. SINYAVSKIY
Keyword(s):  
Service Life ◽  
Electric Power ◽  
High Power ◽  
Electric Propulsion ◽  
Nuclear Power ◽  
Materials Science ◽  
Low Voltage ◽  
Power Input ◽  
Design Bureau ◽  
Rocket Propulsion

At the initiative of S.P.Korolev, in 1959, Special Design Bureau No.1 (now RSC Energia) established the High-temperature Power Engineering and Electric Propulsion Center which was tasked with development of nuclear electric propulsion for heavy interplanetary vehicles. Selected as the source of electric power was a nuclear power unit based on a thermionic converter reactor, and selected as the engine was a stationary low-voltage magnetoplasmodynamic (MPD) high-power (0.5–1.0 MW) thruster which had thousands of hours of service life. The paper presents the results of extensive efforts in research, development, design, materials science experiments, and tests on the MPD-thruster, including the results of development and 500-hours life tests of an MPD-thruster with a 500-600 kW electric power input that used lithium propellant. The world’s first lithium 17 kW MPD-thruster was built and successfully tested in space. The paper points out that to this day nobody has surpassed the then achievements of RSC Energia neither in thruster output during long steady-state operation, nor in performance and service life. Key words: Martian expeditionary vehicle, nuclear electric rocket propulsion system, electric rocket thruster, magnetoplasmodynamic thruster, lithium, cathode, anode, barium, electric propulsion tests in space.

scholarly journals The search for new materials and the role of novel processing routes

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Peter J. Wellmann
Keyword(s):  
Materials Science ◽  
Research Society ◽  
Subsequent Treatment ◽  
European Council ◽  
Trial And Error ◽  
Human History ◽  
New Materials ◽  
Materials Research ◽  
Novel Processing

AbstractThroughout human history, most further developments or new achievements were accompanied by new materials or new processes that enabled the technologic progress. With concrete devices and applications in mind, synthesis and subsequent treatment of materials naturally went along with the progress. The aim of the underlying article is to spot the role of optimization, of discovery, of trial-and-error approaches, of fundamentals and curiosity driven design and development. In a consecutive examination, five missions addressing the challenges facing our world (identified by the European Council) will be cross linked with seven topical areas from materials science defined by the European Materials Research Society. The scope of this examination is to identify approaches and methods to further develop and innovate materials which form the basis of the anticipated solutions.

scholarly journals Synthesis and Characterization of a Bioconjugate Based on Oleic Acid and L-Cysteine

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1791
Author(s):  
Marco Vizcarra-Pacheco ◽  
María Ley-Flores ◽  
Ana Mizrahim Matrecitos-Burruel ◽  
Ricardo López-Esparza ◽  
Daniel Fernández-Quiroz ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Materials Science ◽  
Critical Micellar Concentration ◽  
Synthesis And Characterization ◽  
New Materials ◽  
Visible Spectroscopy ◽  
Amide Bonds ◽  
Transmission Electron ◽  
Self Assembled

One of the main challenges facing materials science today is the synthesis of new biodegradable and biocompatible materials capable of improving existing ones. This work focused on the synthesis of new biomaterials from the bioconjugation of oleic acid with L-cysteine using carbodiimide. The resulting reaction leads to amide bonds between the carboxylic acid of oleic acid and the primary amine of L-cysteine. The formation of the bioconjugate was corroborated by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and nuclear magnetic resonance (NMR). In these techniques, the development of new materials with marked differences with the precursors was confirmed. Furthermore, NMR has elucidated a surfactant structure, with a hydrophilic part and a hydrophobic section. Ultraviolet-visible spectroscopy (UV-Vis) was used to determine the critical micellar concentration (CMC) of the bioconjugate. Subsequently, light diffraction (DLS) was used to analyze the size of the resulting self-assembled structures. Finally, transmission electron microscopy (TEM) was obtained, where the shape and size of the self-assembled structures were appreciated.

scholarly journals Laboratory-Scale Processing and Performance Assessment of Ti–Ta High-Temperature Shape Memory Spring Actuators

2021 ◽  
Author(s):  
A. Paulsen ◽  
H. Dumlu ◽  
D. Piorunek ◽  
D. Langenkämper ◽  
J. Frenzel ◽  
...  
Keyword(s):  
High Temperature ◽  
Shape Memory ◽  
Detrimental Effect ◽  
Wire Drawing ◽  
Fast Heating ◽  
Heating And Cooling ◽  
Arc Melting ◽  
Ω Phase ◽  
And Performance

AbstractTi75Ta25 high-temperature shape memory alloys exhibit a number of features which make it difficult to use them as spring actuators. These include the high melting point of Ta (close to 3000 °C), the affinity of Ti to oxygen which leads to the formation of brittle α-case layers and the tendency to precipitate the ω-phase, which suppresses the martensitic transformation. The present work represents a case study which shows how one can overcome these issues and manufacture high quality Ti75Ta25 tensile spring actuators. The work focusses on processing (arc melting, arc welding, wire drawing, surface treatments and actuator spring geometry setting) and on cyclic actuator testing. It is shown how one can minimize the detrimental effect of ω-phase formation and ensure stable high-temperature actuation by fast heating and cooling and by intermediate rejuvenation anneals. The results are discussed on the basis of fundamental Ti–Ta metallurgy and in the light of Ni–Ti spring actuator performance.

High Temperature Mechanical Properties of Ni-Al-Cr Based Alloys with Refractory Alloying Elements

2006 ◽  
Vol 510-511 ◽  
pp. 358-361
Author(s):  
Won Yong Kim ◽  
Han Sol Kim ◽  
In Dong Yeo ◽  
Mok Soon Kim
Keyword(s):  
High Temperature ◽  
Volume Fraction ◽  
Lattice Parameter ◽  
Alloying Elements ◽  
Solid Solution Hardening ◽  
High Temperature Strength ◽  
High Temperature Mechanical Properties ◽  
Die Materials ◽  
The Matrix ◽  
Effective Role

We report on advanced Ni3Al based high temperature structural alloys with refractory alloying elements such as Zr and Mo to be apllied in the fields of die-casting and high temperature press forming as die materials. The duplex microstructure consisting of L12 structured Ni3Al phase and Ni5Zr intermetallic dispersoids was observed to display the microstructural feature for the present alloys investigated. Depending on alloying elements, the volume fraction of 2nd phase was measured to be different, indicating a difference in solid solubility of alloying elements in the matrix γ’ phase. Lattice parameter of matrix phase increased with increasing content of alloying elements. In the higher temperature region more than 973K, the present alloys appeared to show their higher strength compared to those obtained in conventional superalloys. On the basis of experimental results obtained, it is suggested that refractory alloying elements have an effective role to improve the high temperature strength in terms of enhanced thermal stability and solid solution hardening.

NEUTRON POWDER DIFFRACTION AND OXIDE SUPERCONDUCTORS

1993 ◽  
Vol 07 (16n17) ◽  
pp. 3077-3093 ◽  
Author(s):  
A.W. HEWAT
Keyword(s):  
Heavy Metals ◽  
High Temperature ◽  
Powder Diffraction ◽  
Neutron Powder Diffraction ◽  
Oxide Superconductors ◽  
X Rays ◽  
New Materials ◽  
Oxidation Reduction ◽  
High Temperature Oxide ◽  
Temperature Oxide

Neutron powder diffraction has been essential for understanding the structures of the new high temperature oxide superconductors because of the difficulty in locating oxygen with X-rays in the presence of heavy metals, especially when single crystals are usually not available. This understanding lead to the discovery of new materials. In this paper we will show how it also sheds light on the crystal chemistry of oxide superconductors—the effects of oxidation/reduction, phase separation, pressure etc.

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