Effect of heat treatments on canola press oils. II. Oxidative stability

1991 ◽  
Vol 68 (6) ◽  
pp. 407-411 ◽  
Author(s):  
Elizabeth M. Prior ◽  
Vivekenand S. Vadke ◽  
Frank W. Sosulski
1991 ◽  
Vol 68 (6) ◽  
pp. 401-406 ◽  
Author(s):  
Elizabeth M. Prior ◽  
Vivekenand S. Vadke ◽  
Frank W. Sosulski
Keyword(s):  

Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.


Author(s):  
A. W. West

The influence of the filament microstructure on the critical current density values, Jc, of Nb-Ti multifilamentary superconducting composites has been well documented. However the development of these microstructures during composite processing is still under investigation.During manufacture, the multifilamentary composite is given several heat treatments interspersed in the wire-drawing schedule. Typically, these heat treatments are for 5 to 80 hours at temperatures between 523 and 573K. A short heat treatment of approximately 3 hours at 573K is usually given to the wire at final size. Originally this heat treatment was given to soften the copper matrix, but recent work has shown that it can markedly change both the Jc value and microstructure of the composite.


Author(s):  
P. J. Lee ◽  
D. C. Larbalestier

Several features of the metallurgy of superconducting composites of Nb-Ti in a Cu matrix are of interest. The cold drawing strains are generally of order 8-10, producing a very fine grain structure of diameter 30-50 nm. Heat treatments of as little as 3 hours at 300 C (∼ 0.27 TM) produce a thin (1-3 nm) Ti-rich grain boundary film, the precipitate later growing out at triple points to 50-100 nm dia. Further plastic deformation of these larger a-Ti precipitates by strains of 3-4 produces an elongated ribbon morphology (of order 3 x 50 nm in transverse section) and it is the thickness and separation of these precipitates which are believed to control the superconducting properties. The present paper describes initial attempts to put our understanding of the metallurgy of these heavily cold-worked composites on a quantitative basis. The composite studied was fabricated in our own laboratory, using six intermediate heat treatments. This process enabled very high critical current density (Jc) values to be obtained. Samples were cut from the composite at many processing stages and a report of the structure of a number of these samples is made here.


2008 ◽  
Vol 128 (4) ◽  
pp. 289-297 ◽  
Author(s):  
Tsutomu Mizuno ◽  
Shigemi Enoki ◽  
Takashi Asahina ◽  
Takayuki Suzuki ◽  
Hiroyuki Maeda ◽  
...  

2019 ◽  
Author(s):  
Georg Dewald ◽  
Saneyuki Ohno ◽  
Marvin Kraft ◽  
Raimund Koerver ◽  
Paul Till ◽  
...  

<p>All-solid-state batteries are often expected to replace conventional lithium-ion batteries in the future. However, the practical electrochemical and cycling stability of the best-conducting solid electrolytes, i.e. lithium thiophosphates, are still critical issues that prevent long-term stable high-energy cells. In this study, we use <i>stepwise</i><i>cyclic voltammetry </i>to obtain information on the practical oxidative stability limit of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>, a Li<sub>2</sub>S‑P<sub>2</sub>S<sub>5</sub>glass, as well as the argyrodite Li<sub>6</sub>PS<sub>5</sub>Cl solid electrolytes. We employ indium metal and carbon black as the counter and working electrode, respectively, the latter to increase the interfacial contact area to the electrolyte as compared to the commonly used planar steel electrodes. Using a stepwise increase in the reversal potentials, the onset potential at 25 °C of oxidative decomposition at the electrode-electrolyte interface is identified. X‑ray photoelectron spectroscopy is used to investigate the oxidation of sulfur(-II) in the thiophosphate polyanions to sulfur(0) as the dominant redox process in all electrolytes tested. Our results suggest that after the formation of these decomposition products, significant redox behavior is observed. This explains previously reported redox activity of thiophosphate solid electrolytes, which contributes to the overall cell performance in solid-state batteries. The <i>stepwise cyclic voltammetry</i>approach presented here shows that the practical oxidative stability at 25 °C of thiophosphate solid electrolytes against carbon is kinetically higher than predicted by thermodynamic calculations. The method serves as an efficient guideline for the determination of practical, kinetic stability limits of solid electrolytes. </p>


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