New Battery Electrolytes for Low and High Temperatures: Liquid and Solid Ammoniates for High Energy Batteries: I . Sodium Iodide and Lithium Perchlorate Ammoniates

1988 ◽  
Vol 135 (3) ◽  
pp. 587-591 ◽  
Author(s):  
J. Badoz‐Lambling ◽  
M. Bardin ◽  
C. Bernard ◽  
B. Fahys ◽  
M. Herlem ◽  
...  
Keyword(s):  
High Temperatures ◽  
Sodium Iodide ◽  
Lithium Perchlorate ◽  
High Energy

Yttrium Implantation and Manganese Addition Element Effects on the High Temperature Oxidation Resistance of a Model Steel

2008 ◽  
Vol 595-598 ◽  
pp. 897-905
Author(s):  
Eric Caudron ◽  
Régis Cueff ◽  
Christophe Issartel ◽  
N. Karimi ◽  
Frédéric Riffard ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
High Temperatures ◽  
Mixed Oxides ◽  
Rutherford Backscattering Spectrometry ◽  
High Energy ◽  
X Ray Diffraction ◽  
Temperature Oxidation ◽  
X Ray ◽  
Steel Oxidation ◽  
Yttrium Implantation

Manganese addition and subsequent yttrium implantation effects on extra low carbon steel were studied by Rutherford Backscattering Spectrometry (RBS), Reflection High Energy Electron Diffraction (RHEED), X-ray Diffraction (XRD) and Glancing Angle X-ray Diffraction (GAXRD). Thermogravimetry and in situ X-Ray Diffraction at 700°C and PO2=0.04 Pa for 24h were used to determine the manganese alloying addition and subsequent yttrium implantation effects on reference steel oxidation resistance at high temperatures. This study clearly shows the combined effect of manganese alloying addition and subsequent yttrium implantation which promotes the formation of several yttrium mixed oxides seem to be responsible for the improved reference steel oxidation resistance at high temperatures.

Growth of Niobium Films at High Temperatures on Sapphire

1996 ◽  
Vol 440 ◽  
Author(s):  
T. Wagner
Keyword(s):  
High Temperatures ◽  
Basal Plane ◽  
Misfit Strain ◽  
High Energy ◽  
Total Density ◽  
Initial Growth ◽  
Island Size ◽  
Transmission Electron ◽  
Orientation Density

AbstractThe growth and microstructural evolution of Nb thin films on the basal plane of α-Al2O3 were studied at different growth temperatures. The influence of island orientation, density, and misfit strain energy on the growth behavior of Nb films on (0001)α-Al2O3 at high temperatures has been investigated. The films were grown by MBE at 900°C and 1100°C. At these temperatures the Nb grows in the Volmer-Weber growth mode on the basal plane. In-situ reflection high energy electron diffraction (RHEED), Auger electron spectroscopy (AES) and transmission electron microscopy (TEM) investigations revealed that in the initial growth stage, Nb nuclei with different epitaxial orientations were formed. This leads to different orientations of thicker Nb films at different growth temperatures. At a growth temperature of 900°C the Nb{111} planes are parallel to the sapphire basal plane whereas at 1100°C Nb grows with the {110) planes parallel to the basal plane of sapphire. The formation of two different epitaxial orientations of thick Nb films can only be explained by considering both the change in the total density of Nb islands with temperature and the influence of island size on their total energy.

Influence of Distinct Manufacturing Processes on the Microstructure of Ni-Based Metal Matrix Composites Submitted to Long Thermal Exposure

2019 ◽  
Vol 809 ◽  
pp. 79-86
Author(s):  
Georges Lemos ◽  
Márcio C. Fredel ◽  
Florian Pyczak ◽  
Ulrich Tetzlaff
Keyword(s):  
Metal Matrix Composites ◽  
High Temperatures ◽  
Metal Matrix ◽  
Thermal Exposure ◽  
High Energy ◽  
Matrix Composites ◽  
Microstructural Stability ◽  
Aerospace Applications ◽  
Plasma Sintering ◽  
Energy Processes

Metal Matrix Composites (MMCs) are known for their remarkable properties, by combining materials from different classes. Ni-based MMCs are a promising group of heat-resistant materials, targeting aerospace applications. A discontinuously reinforced Inconel X-750/TiC 15 vol.% MMC was proposed for use in lighter, creep resistant turbine elements, with the aim to endure service temperatures up to 1073 K (800 °C). However, their microstructural stability at high temperatures for long periods of time remained to be further investigated. To address this need, specimens were produced by both conventional hot pressing and spark plasma sintering, using powders milled by low and high energy processes, followed by long isothermal aging. The treatments were conducted at 973 and 1073 K, for times between 50 and 1000 hours. The resulting samples were investigated with XRD and EDS techniques for phase analysis. In addition, measurements of hardness were made to monitor changes in mechanical behavior. It was found that, for each different manufacturing process, the amount, distribution and size of γ’ and other precipitates notably vary during the overaging process. Consequently, the amount of elements kept in solid solution also shifted with time. Furthermore, the study shows how distinct initial microstructures, resulting from diverse fabrication processes, differently impact the microstructural stability over long times of exposure to high temperatures.

The Barrier to Rotation in 9,10-Bis(2,3-dimethylphenyl)phenanthrene: Conformational Interconversion Observed at High Temperatures by Means of Gas Chromatography

1985 ◽  
Vol 38 (2) ◽  
pp. 307 ◽  
Author(s):  
Y Lai ◽  
PJ Marriott ◽  
B Tan
Keyword(s):  
Gas Chromatography ◽  
High Temperatures ◽  
Thermodynamic Data ◽  
Energy Barrier ◽  
Variable Temperature ◽  
High Energy ◽  
Free Rotation ◽  
Temperature Range ◽  
Conformational Interconversion ◽  
High Energy Barrier

A mixture of the syn and anti conformers of 9,10-bis(2,3- dimethylphenyl ) phenanthrene was prepared. The unexpectedly high energy barrier for the free rotation of the two aryl rings is described. Variable temperature 1H n.m.r . studies failed to provide thermodynamic data for the conformational inter-conversion due to limitations in practicably measurable temperature range. The energies of activation for both interconversion processes were, however, determined by gas chromatographic studies in the temperature range of 225-300°C.

Enhanced Performance Induced by Phase Transition of Li2FeSiO4 upon Cycling at High Temperature

2020 ◽  
Author(s):  
Titus Masese ◽  
Yuki Orikasa ◽  
Kentaro Yamamoto ◽  
Yosuke Horie ◽  
Rika Hagiwara ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Transformation ◽  
High Temperature ◽  
High Temperatures ◽  
Room Temperature ◽  
High Energy ◽  
Temperature Cycling ◽  
High Energy Density ◽  
Slow Phase ◽  
Rate Performance

<p>Owing to its low cost, thermal stability and theoretically high capacity, Li<sub>2</sub>FeSiO<sub>4 </sub>has been a promising cathode material for high-energy-density Li-ion (Li<sup>+</sup>) battery system. However, its poor rate performance and high voltage polarisation attributed to innately slow Li<sup>+</sup> kinetics at room temperature, has fundamentally curbed its ascent into prominence. Here, the rate performance of Li<sub>2</sub>FeSiO<sub>4</sub> at high temperatures in electrolyte comprising molten salt (ionic liquid) was investigated. Subsequently, a comparison of the phase transition behaviour observed at both high-temperature and room-temperature cycling was elucidated. Our results show that remarkable rate performance with good cyclability in conjunction with low voltage polarisation is attained upon cycling of Li<sub>2</sub>FeSiO<sub>4</sub> at high temperatures, due to the faster phase transformation from unstable monoclinic structures to thermodynamically stable orthorhombic structures triggered by elevated temperature. What this study adds to the burgeoning body of research work relating to the silicates is that the initially slow phase transformation behaviour observed at room temperature can significantly be enhanced upon cycling at elevated temperatures.</p>

Study on Zr–Si/W(100) Surface at High Temperatures by Reflection High Energy Electron Diffraction

1999 ◽  
Vol 38 (Part 1, No. 5A) ◽  
pp. 2951-2952 ◽  
Author(s):  
Takashi Kawano ◽  
Riichiro Mitsuhashi ◽  
Yoshihide Kimura ◽  
Ryuichi Shimizu
Keyword(s):  
Electron Diffraction ◽  
High Temperatures ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron

Mechanochemical Nitride Synthesis

2007 ◽  
Vol 554 ◽  
pp. 51-57 ◽  
Author(s):  
Derek P. Thompson
Keyword(s):  
High Temperatures ◽  
Mechanochemical Synthesis ◽  
Room Temperature ◽  
High Energy ◽  
Milling Process ◽  
High Price ◽  
Diamond Machining ◽  
Structural Applications ◽  
The Cost ◽  
Frequent Criticism

A frequent criticism of nitride materials during the last 30 years, and especially those designed for structural applications has been that the cost is too high by a factor of (say) 10. In the competition with cheaper materials (albeit with poorer properties and shorter lifetimes), users have generally preferred to go for the cheaper option, rather than the more expensive nitrides. Despite many attempts to address this issue, the cost of nitride processing has remained high – due to the high price of starting materials, the high temperatures needed for firing, and also the finishing costs (often involving diamond machining), and this has been a major factor limiting the market share enjoyed by these materials. A number of studies have been reported recently using the technique of mechanochemical synthesis, in which nitrogen is incorporated (usually via ammonia) into the starting powders during a high-energy milling process (at room temperature). In the subsequent firing, considerably lower temperatures are needed to produce the resulting final nitride product(s). In this presentation, the technique of mechanochemical synthesis is discussed, the range of materials that have been produced are reviewed, and the potential of this technique for reducing the cost of bulk nitride production is reviewed.

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