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1.
D. El Allam E. Hayer M. Gaune-Escard J. P. Bros 《Journal of Thermal Analysis and Calorimetry》1991,37(8):1687-1695
In order to fill the evident gap in the thermodynamic data of nickel-palladium-gallium and nickel-palladium-indium ternary alloys, the enthalpies of formation of these systems in the liquid state have been determined. This was achieved by means of a very high temperature calorimeter (T<1800 K), using the direct drop method, and based on analogous measurements of the respective binary alloys previously published. Complete automation of the calorimeter led to a good precision even at the highest temperatures. The enthalpies of formation of the ternary liquid alloys were measured between 1400 and 1600 K on the whole composition range. As in the limiting binary systems, enthalpies of formation are negative and non temperature dependent at any composition.
Zusammenfassung Um die Lücke hinsichtlich thermodynamischer Daten von Nickel-Palladium-Gallium und Nickel-Palladium-Indium Legierungen zu füllen, wurden die Bildungsenthalpien dieser ternÄren Systeme im flüssigen Zustand bestimmt. Dies erfolgte mittels eines Kalorimeters für sehr hohe Temperaturen (T<1800 K), unter Verwendung der direkten Einwurfmethode auf der Basis früher veröffentlichter Messungen an den entsprechenden binÄren Systemen. Die Bildungsenthalpien der flüssigen ternÄren Legierungen wurden zwischen 1400 und 1600 K über den gesamten Zusammensetzungsbereich bestimmt. VollstÄndige Automation des Kalorimeters bewirkte hohe PrÄzision selbst bei den höchsten Temperaturen. Wie in den begrenzenden binÄren Systemen sind die Bildungsenthalpien negativ und bei allen Zusammensetzungen nicht temperaturabhÄngig.相似文献
2.
The molar enthalpies of the solid–solid and solid–liquid phase transitions were determined by differential scanning calorimetry
for pure TbCl3 and KTb2Cl7, RbTb2Cl7, CsTb2Cl7, K3TbCl6, Rb3TbCl6 and Cs3TbCl6 compounds. Both types of compounds, i.e. M3TbCl6 and MTb2Cl7 (M=K, Rb, Cs) melt congruently and show additionally a solid–solid phase transition with a corresponding enthalpy Δtrs
H
0 of 6.1, 7.6 and 7.0 kJ mol–1 for potassium, rubidium and caesium M3TbCl6 compounds andΔtrs
H
0 of 17.1 (rubidium) and of 12.1 and 10.9 kJ mol–1 (caesium) for MTb2Cl7 compounds, respectively. The enthalpies of fusion were measured for all the above compounds with the exception of Rb3TbCl6 and Cs3TbCl6. The heat capacities of the solid and liquid compounds have been determined by differential scanning calorimetry (DSC) in
the temperature range 300–1100 K. The experimental heat capacity strongly increases in the vicinity of a phase transition,
but varies smoothly in the temperature ranges excluding these transformations. C
p data were fitted by an equation, which provided a satisfactory representation up to the temperatures of C
p discontinuity. The measured heat capacities were checked for consistency by calculating the enthalpy of formation of the
liquid phase, which had been previously measured. The results obtained agreed satisfactorily with these experimental data.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
Summary. Several compounds may exist in LnCl3–MCl mixtures. Those corresponding to the M
2
LnCl5 and MLn
2Cl7 stoichiometries are formed in a few systems only, with diverse stability strongly dependent on both the corresponding lanthanide
and alkali metal. On the other hand, M
3
LnCl6 that occur in most systems have a far larger stability range and melt congruently. These latter compounds were investigated
in the present work by differential scanning calorimetry and electrical conductivity measurements. The thermodynamic and transport
properties were correlated to structural features and related to the mechanism of compound formation.
Corresponding author. E-mail: Marcelle.Gaune-Escard@polytech.univ-mrs.fr
Received October 2, 2002; accepted November 6, 2002
Published online April 24, 2003
RID="a"
ID="a" This paper is dedicated to Professor H. Gamsj?ger on the occasion of his birthday 相似文献
4.
G. A. Bukatova S. A. Kuznetsov M. Gaune-Escard 《Russian Journal of Electrochemistry》2007,43(8):929-935
Rare-earth metal borides are widely used in different fields of modern techniques. Electrochemical synthesis at moderate temperatures
(973–1023 K) is a cost-effective alternative to direct reaction techniques. The present work reports the mechanism and kinetics
of boron and europium, boron and neodymium joint electrodischarge in chloride-fluoride molten systems. The optimum regimes
of europium and neodymium borides electrodeposition are worked out on the base of voltammetric experiments. Europium compound
is synthesized as a single-phase EuB6 product, while neodymium compounds is co-deposited as NdB4 and NdB6.
Published in Russian in Elektrokhimiya, 2007, Vol. 43, No. 8, pp. 978–984.
The article was translated by the authors. 相似文献
5.
Blanka Kubikova Miroslav Boca Marcelle Gaune-Escard 《Monatshefte für Chemie / Chemical Monthly》2008,139(6):587-590
The phase equilibria in the K2TaF7–TaF5 binary system were determined up to x
TaF5 = 0.5 by means of differential scanning calorimetry. XRD diffraction analysis of solidified mixtures was performed. Besides
the K2TaF7 and KTaF6 phases, the presence of a third phase was observed, as well. It was suggested that the last phase melts incongruently.
Correspondence: B. Kubikova, Institute of Inorganic Chemistry SAS, Dúbravská cesta 9, Bratislava, 845 36, Slovakia. 相似文献
6.
Marcelle Gaune-Escard A. Bogacz L. Rycerz W. Szczepaniak 《Journal of Thermal Analysis and Calorimetry》1995,45(5):1117-1124
Present work is a part of thermodynamic research program on the MX?LnX3 system (M=alkali metal,X=Cl, Br andLn=lanthanide). Molar enthalpies of mixing in the LiBr?NdBr3, NaBr?NdBr3 and KBr?NdBr3 liquid binary systems have been determined at temperature 1063 K by direct calorimetry in the whole range of composition. Investigated systems are generally characterized by negative enthalpies of mixing with minimum atX NdBr3≈0.3–0.4. These enthalpies decrease with decrease of ionic radii of alkali metals. Molar enthalpies of solid-solid and solid-liquid phase transitions of K3NdBr6 and Cs3NdBr6 have been also determined by differential scanning calorimetry (DSC). K3NdBr6 is formed at 689 K from KBr and K2NdBr5 with enthalpy of 44.0 kJ·mol?1 whereas Cs3NdBr6 is stable at ambient temperature and undergoes phase transition in the solid state at 731 K with enthalpy of 8.8 kJ·mol?1. Enthalpies of melting have been also determined. 相似文献
7.
Rycerz L. Cieślak-Golonka M. Ingier-Stocka E. Gaune-Escard M. 《Journal of Thermal Analysis and Calorimetry》2003,72(1):231-239
Several experimental techniques were used to characterise the physicochemical properties of the TbBr3-NaBr system. The phase diagram determined by DSC, exhibits an eutectic and a Na3TbBr6 stoichiometric compound that decomposes peritectically (759 K) shortly after a solid-solid phase transition (745 K). The
eutectic composition, x(TbBr3)=39.5 mol%, was obtained from the Tamman method. This mixture melts at 699 K. With the corresponding enthalpy of about 16.1
kJ mol-1. Diffuse reflectance spectra of the pure components and their solid mixtures (after homogenisation in the liquid state) confirmed
the existence of new phase exhibiting its own spectral characteristics, which may be possibly related to the formation of
Na3TbBr6 in this system. Additionally, the electrical conductivity of TbBr3-NaBr liquid mixtures was measured down to temperatures below solidification over the whole composition range.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Rycerz Leszek Ingier-Stocka Ewa Gaune-Escard Marcelle 《Journal of Thermal Analysis and Calorimetry》2009,97(3):1015-1021
Journal of Thermal Analysis and Calorimetry - Phase equilibrium in the CeBr3–CsBr binary system was established from differential scanning calorimetry (DSC). This system includes three... 相似文献
9.
A. Dańczak B. Salamon J. Kapała L. Rycerz M. Gaune-Escard 《Journal of Thermal Analysis and Calorimetry》2017,130(1):25-33
The phase equilibria in the terbium(III) chloride–lithium chloride pseudobinary system were established by means of differential scanning calorimetry. It was established that the pure terbium(III) chloride undergoes solid–solid phase transition at 790 K and melts at 859 K. The TbCl3–LiCl pseudobinary system is characterized by the existence of two compounds. First one, namely Li3TbCl6, forms at 553 K and melts incongruently at 727 K. Second compound, LiTbCl4, decomposes in the solid state at 609 K. The composition of Li3TbCl6–TbCl3 eutectic corresponding to terbium(III) chloride mole fraction x = 0.521 (T = 665 K) was found from Tammann plot, which predict, through application of the lever rule, the variation of the enthalpy associated with eutectic melting as a function of composition. The obtained results have been compared with the literature data concerning for the TbCl3–LiCl pseudobinary system. The phase diagram of the TbCl3–LiCl pseudobinary system was also optimized by CALPHAD method. 相似文献
10.
I. Chojnacka L. Rycerz M. Berkani M. Gaune-Escard 《Journal of Thermal Analysis and Calorimetry》2012,108(2):481-488
Phase equilibrium in the DyBr3–RbBr binary system was established from differential scanning calorimetry measurements. This system exhibits three compounds,
namely Rb3DyBr6, Rb2DyBr5, and RbDy2Br7, and two eutectics located at DyBr3 molar fraction x = 0.116 (T = 886 K) and x = 0.458 (T = 702 K), respectively. Rb3DyBr6 undergoes a solid–solid phase transition at 726 K and melts congruently at 1,059 K. Rb2DyBr5 and RbDy2Br7 melt incongruently at 737 and 748 K, respectively. The electrical conductivity of DyBr3–RbBr liquid mixtures was measured over the whole composition range. Results obtained are discussed in term of possible complex
formation. 相似文献