Thermodynamic properties of alloys In—Tb system

2021 ◽  
Vol 2021 (2) ◽  
pp. 79-89
Author(s):  
A.S. Dudnik ◽  
◽  
V.G Kudin ◽  
L. O. Romanova ◽  
V. S. Sudavtsova ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Enthalpy Of Mixing ◽  
Thermochemical Properties ◽  
Trend Line ◽  
P Elements ◽  
Serial Number ◽  
Concentration Interval ◽  
Heavy Lanthanides ◽  
Modern Work

The method of isoportic calorimetry investigated the thermochemical properties of the melt In—Tb system in the range of compositions 0 < xIn < 0,4 at 1625 ± 1 K. The obtained data were extrapolated on a non-investigated concentration interval, given that when xTb = 1 integral and partial to Tb enthalpia mixing is zero. It was established that the first partial for Terbium and the minimum enthalpy of mixing is –145 ± 7 and –40,1 ± 0,2 kJ/mol respectively. Comparison of ΔHmin, the melt of five previously investigated In—Ln systems from the serial number Ln (zLn), together with the data obtained in this papper, showed that they are described by one trend line. For ΔHmin In—Eu (Yb) melts (Yb) are very slight deviations from the trend line. But for dimensional factor, these deviations from the trend line are more significant. Enthalpia of the formation of some In—Ln intermetallides are known, with most of them relate to the LnIn3 compound. But there is no full reconciliation between these data. The results of the most modern work exhibit less dependence on the serial number of lanthanides and are more exothermic for heavy lanthanides, compared with other data. Comparing thermochemical properties of double Sn (Sb) —REM melt systems. It has been established that the energy of the interaction between the data p-elements and REM increases in such a sequence: In-REM → Sn—REM → Sb—REM. This is due to the fact that the stibium is the best acceptor of electrons. Keywords: thermochemical properties, melts, compounds, In, Tb.

Thermodynamic properties of alloys binary In—Pr (Nd) and ternary In—Pr (Nd)—Ni systems

2021 ◽  
Vol 2021 (3) ◽  
pp. 102-108
Author(s):  
A. S. Dudnik ◽  
◽  
V. G. Kudin ◽  
L. O. Romanova ◽  
V. S. Sudavtsova ◽  
...  
Keyword(s):  
Ordinal Number ◽  
Enthalpy Of Mixing ◽  
Enthalpies Of Formation ◽  
Complete Agreement ◽  
Size Factor ◽  
Thermochemical Properties ◽  
Trend Line ◽  
Isoperibolic Calorimetry ◽  
Heavy Lanthanides ◽  
Modern Work

The thermochemical properties of In—Pr system melts in the range of compositions 0 < xIn < 0,4 and In—Nd in the whole concentration range at 1573 ± 1 K were investigated by isoperibolic calorimetry. The obtained data for the In—Pr system melts were extrapolated to the unexplored concentration interval, taking into account that at xPr = 1 the integral and partial mixing for Pr enthalpy are equal to zero. It was found that the first partial for Pr and the minimum enthalpy of mixing are equal to –139 ± 11 and –40,3 ± 0,2 kJ / mol, respectively. For the In—Nd system the first partial for In and Nd, the minimum enthalpy of mixing is equal to −131,7 ± 11, −140,6 ± 12 і –43,3  0,2 kJ / mol, respectively. Comparison of ΔHmin, melts of the five previously studied In—Ln systems from the ordinal number Ln (zLn) together with the data obtained in this work showed that they are described by a single trend line. For ΔHmin of melts of In—Eu (Yb) systems there are very insignificant deviations from the trend line. But for the size factor, these deviations from the trend line are more significant. The enthalpies of formation of some intermetallics of In—Ln systems are known, and most of them belong to the compound LnIn3. But there is no complete agreement between these data. The results of the most modern work show less dependence on the serial number of lanthanide and are more exothermic for heavy lanthanides, compared with other data. Keywords: thermochemical properties, compounds, melts, In, Pr, Nd.

Thermodynamic properties of melts of Bi—Eu system

2021 ◽  
Vol 2021 (2) ◽  
pp. 90-100
Author(s):  
V. S. Sudavtsova ◽  
◽  
V,A, Shevchuk ◽  
L. O. Romanova ◽  
M. I. Ivanov ◽  
...  
Keyword(s):  
Enthalpy Of Mixing ◽  
Enthalpies Of Formation ◽  
Thermochemical Properties ◽  
Melting Temperatures ◽  
Large Size ◽  
Intermediate Phases ◽  
Ideal Solutions ◽  
First Time ◽  
Enthalpy Data ◽  
The Eu

The thermochemical properties of alloys were determined for the first time by calorimetry Bi—Eu system at a temperature of 1200 K in the range of 0 ≤ xBi ≤ 0,2 and 0,77 ≤ xBi ≤ 1,0. It is established that the minimum value of the enthalpy of mixing is equal to –61,7 ± 0,5 kJ / mol at xBi = 0,5. = –184,7 ± 16,7 kJ / mol, = = –206,9 ± 21,8 kJ / mol. The activities of the components were calculated according to the model of an of the ideal associated solution (IAR), using the thermochemical properties of the melts of the Bі—Eu. system. It has been established that the activities of the components show large negative deviations from ideal solutions. To predict the enthalpies of formation of LnBi compounds, the available literature data on these parameters are analyzed and the most reliable ones are presented as a dependence on ∆fH = f(ZLn). It is established that the enthalpies of formation LnBi change smoothly and monotonically with the exception of Bi—Eu and Bi—Yb systems. This is due to the large size factors for the last two systems. To combine all the enthalpy data of Ln—Bi intermetallic formation of Ln—Bi systems depending on the sequence number Ln, we need similar values for the Eu—Bi compound. But at present they are not known, so based on the above, it was assumed that the value of the minimum enthalpy of mixing will be close to the enthalpy of formation of this compound. This hypothesis is confirmed by data on the enthalpies formation of phase YbBi and equiatomic melts of binary of Yb—Bi system. To confirm the thermodynamic data, we compare the known melting temperatures of the formed intermediate phases, known from the diagrams state Bi—Ln system. The obtained dependences correlate with ∆fH = f(ZLn ) і ∆V = f(ZLn). This means that the predictions of thermochemical properties accurately reflect the nature of the considered melts of the Bi—Eu system. Keywords: thermochemical properties, melts, compounds, Bi, Eu.

scholarly journals Comparative analyses of thermodynamic properties assessments, performed by geometric models: Application to the Ni-Bi-Zn system

2013 ◽  
Vol 49 (3) ◽  
pp. 347-352 ◽  
Author(s):  
V. Gandova ◽  
G. Vassilev
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Thermodynamic Properties ◽  
Wide Temperature Range ◽  
Excess Energy ◽  
Energy Calculation ◽  
Thermochemical Properties ◽  
Multicomponent Systems ◽  
Ternary Interaction ◽  
Geometric Models

The thermochemical properties of metals and alloys are essential for the chemists to invent and improve metallurgical and materials? design processes. However, the properties of multicomponent systems are still scarcely known due to experimental difficulties and the large number of related systems. Thus, the modelling of some thermodynamic properties would be advantageous when experimental data are missing. Considering mentioned facts, geometric models to estimate some thermodynamic properties for the liquid phase of the Ni-Bi-Zn systems. The calculations have been performed in a wide temperature range (1000-2000 K). Ternary interaction parameters for the liquid phase allowing molar Gibbs excess energy calculation have been determined.

scholarly journals Ab-initio study of structural, elastic, electronic and thermodynamic properties of BaxSr1−xS ternary alloys

2015 ◽  
Vol 33 (4) ◽  
pp. 879-886 ◽  
Author(s):  
S. Chelli ◽  
S. Touam ◽  
L. Hamioud ◽  
H. Meradji ◽  
S. Ghemid ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
Lattice Constant ◽  
Theoretical Data ◽  
Calculated Phase Diagram ◽  
Enthalpy Of Mixing ◽  
Ternary Alloys ◽  
Miscibility Gap ◽  
Full Potential ◽  
Vegard’S Law

AbstractThe structural, elastic, electronic and thermodynamic properties of BaxSr1−xS ternary alloys have been investigated using the full-potential (linearized) augmented plane wave method. The ground state properties, such as lattice constant, bulk modulus and elastic constants, are in good agreement with numerous experimental and theoretical data. The dependence of the lattice parameters, bulk modulus and band gap on the composition x was analyzed. Deviation of the lattice constant from Vegard’s law and the bulk modulus from linear concentration dependence (LCD) was observed. The microscopic origins of the gap bowing were explained by using the approach of Zunger et al. The thermodynamic stability of BaxSr1−xS alloy was investigated by calculating the excess enthalpy of mixing, ΔHm and the calculated phase diagram showed a broad miscibility gap with a critical temperature.

Thermodynamic properties and phase equilibria in alloys of Bi—Tm system

2021 ◽  
Vol 2021 (3) ◽  
pp. 93-101
Author(s):  
V. S. Sudavtsova ◽  
◽  
V. A. Shevchuk ◽  
V. G. Kudin ◽  
M. I. Ivanov ◽  
...  
Keyword(s):  
Enthalpy Of Mixing ◽  
Thermochemical Properties ◽  
Melt Mixing ◽  
Gibbs Energies ◽  
Temperature Excess ◽  
Ideal Solutions ◽  
Using Data ◽  
Increasing Temperature ◽  
First Time ◽  
Associated Solution

The thermochemical properties of the melts of the Bi—Tm system at a temperature of 1100 K in the range of compositions 0 ≤ xTm ≤ 0,2 were determined for the first time by the calorimetry method. It is established that the minimum value of the enthalpy of mixing of these liquid alloys is equal to –75,7 ± 0,5 kJ / mol at xTm = 0,65. = = –150,7 ± 16,7 kJ / mol, = –230,9 ± 21,8 kJ / mol. The activities of the components and molar particles of associates were calculated according to the model of an ideal associated solution (IAR), using data on the thermochemical properties of melts of the Bi—Tm system. It was found that the activities of the components in these metallic solutions show very large negative deviations from ideal solutions with a high content of TmBi and Tm2Bi associates. The obtained dependences of the first i i melts of the Bi—Tm system on temperature showed a large steepness of the Bi Bi curve in contrast to the gradual decrease of exothermic values Tm of Tm. This indicates large changes in the structure of the Bi atom with increasing temperature. Excess integral and partial Gibbs energies of Bi-Tm system melt mixing calculated from component activities The absolute values of G in the whole concentration range are smaller than H (G min = –41,8 kJ / mol at xTm = 0,58), and the function G of is more asymmetric, which is caused by the entropy contribution (entropy of mixing of the studied melts is negative, and Smin min = −30,5 J / mol ∙ K at xTm = 0,65). Keywords: thermochemical properties, compounds, melts, Bi, Tm.

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