An analysis of the high-temperature entropy of transition metals

1988 ◽  
Vol 9 (1) ◽  
pp. 159-164 ◽  
Author(s):  
M. Thiessen
Keyword(s):  
High Temperature ◽  
Transition Metals ◽  
Entropy Of Transition

The effect of high-temperature treatment on the formation of nanoscale intermetallic compounds of transition metals in Al–Cu–Mn–Zr alloy

2018 ◽  
Vol 9 (5) ◽  
pp. 609-616
Author(s):  
Tetiana O. Monastyrska ◽  
Alla L. Berezina ◽  
Tetiana M. Labur ◽  
Oleh A. Molebny ◽  
Andrii V. Kotko
Keyword(s):  
High Temperature ◽  
Transition Metals ◽  
Intermetallic Compounds ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Zr Alloy

scholarly journals The Prospects for Processing Reservoir Oil Sludge into Hydrocarbons by Low-Temperature Hydrogenation in Sorbing Electrochemical Matrices in Comparison with Conventional High-Temperature Hydrocracking

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5362
Author(s):  
Anton Maximov ◽  
Aslan Tsivadze ◽  
Alexander Fridman ◽  
Tatyana Kuchinskaya ◽  
Alexander Novikov ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
High Temperature ◽  
Low Temperature ◽  
Transition Metals ◽  
Mesoporous Structure ◽  
Oil Sludge ◽  
Commercial Catalyst ◽  
Low Viscosity ◽  
Yield Of Light Fractions

In this paper, we developed an effective method for purifying oil sludge using a sorbing electrochemical matrix and assessed the prospects of this method in comparison with conventional hydrocracking. We synthesized Ni-W supported hydrocracking catalysts with different morphology and studied their activity under various conditions, we compared the obtained catalysts with commercial catalyst SGK-5. We demonstrated that the introduction of a secondary mesoporous structure in the catalyst leads to an increase in the yield of light fractions to 52 wt.%. The possibility is demonstrated to obtain hydrocarbons from reservoir oil sludge, dispersed into an aqueous solution of detergent, by the method of low-temperature hydrogenation in sorbing electrochemical matrices. The obtained product was characterized by low viscosity, low content of transition metals (<320 ppm), and sulphur (<260 ppm).

Energetics of the oxygen vacancy order-disorder transition in Ba2In2O5

1993 ◽  
Vol 8 (7) ◽  
pp. 1484-1486 ◽  
Author(s):  
T.R.S. Prasanna ◽  
Alexandra Navrotsky
Keyword(s):  
High Temperature ◽  
Oxygen Vacancy ◽  
Configurational Entropy ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Scanning Calorimetry ◽  
Disorder Transition ◽  
First Order ◽  
Enthalpy And Entropy ◽  
Entropy Of Transition

The heat capacity and the enthalpy associated with the reported oxygen vacancy order-disorder transition in Ba2In2O5 were measured by high temperature step scanning calorimetry. The transition temperature is 1205 ± 2 K. The transition appears first order or nearly so. The enthalpy and entropy of transition are 1.3 kJ/mol and 1.1 J/mol K, respectively. The latter is only 4.8% of the configurational entropy, arising from mixing one vacancy and five oxygens per formula unit, 22.5 J/mol K. This suggests that the transition involves only a small fraction of the oxygen vacancies and implies extensive short-range order, SRO, in the high temperature phase.

ARSENIDES OF TRANSITION METALS: THE ARSENIDES OF IRON AND COBALT

1957 ◽  
Vol 35 (5) ◽  
pp. 449-457 ◽  
Author(s):  
R. D. Heyding ◽  
L. D. Calvert
Keyword(s):  
High Temperature ◽  
Transition Metals ◽  
Room Temperature ◽  
Pressure Data ◽  
Decomposition Pressure

Alloys of cobalt and arsenic containing up to 60% As by weight have been studied by means of room temperature and high temperature Debye–Scherrer diagrams. Two compounds exist at room temperature, Co2As and CoAs, both of which undergo crystallographic transformations at higher temperatures, the former between 400 °C. and 500 °C., the latter at about 950 °C. A third compound, probably Co3AS2, is formed by the reaction of Co2As with CoAs above 940 °C. The structures of these compounds are compared with the structures of the corresponding compounds in the iron/arsenic system. These results indicate the necessity of slight revisions to the Co/As diagram, and raise serious questions in respect of the validity of decomposition pressure data reported recently for cobalt arsenides.

ARSENIDES OF THE TRANSITION METALS: II. THE NICKEL ARSENIDES

1957 ◽  
Vol 35 (10) ◽  
pp. 1205-1215 ◽  
Author(s):  
R. D. Heyding ◽  
L. D. Calvert
Keyword(s):  
High Temperature ◽  
Melting Point ◽  
Transition Metals ◽  
Stability Region ◽  
Room Temperature ◽  
Metastable Phase ◽  
The Other ◽  
Incongruent Melting ◽  
Diffraction Patterns ◽  
The Stability

Alloys of nickel and arsenic containing up to 60% As by weight have been studied by means of room temperature and high temperature Debye-Scherrer diagrams. Three compounds have been identified: Ni5As2, Ni12−xAs8 (maucherite), and NiAs (niccolite). The first of these is homogeneous from Ni5As2 to Ni4.8A2 at room temperature, and to Ni4.6As2 above 250 °C., while the latter is homogeneous from NiAs to Ni0.95As. Contrary to expectations the stability region of the compound Ni12−xAs8 is very narrow, and occurs at Ni11As8 rather than at Ni3As2. Evidence is presented in support of Hansen's contention that this compound has an incongruent melting point. Alloys in the region corresponding to Ni4.6As2 undergo two transitions below 200 °C, one of which is martensitic and produces a metastable phase, while the other is believed to result in the formation of a new compound, as yet unidentified. The diffraction patterns are discussed in some detail.

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