Estimation of free energies for Li8SiO6 and Li4SiO4 and calculation of the phase diagram of the Li-Si-O system

1988 ◽  
Vol 151 (2) ◽  
pp. 101-107 ◽  
Author(s):  
H. Migge
Keyword(s):  
Phase Diagram ◽  
Free Energies

Thermodynamic Calculation of Bi-Au-Lu, Nd Ternary Systems

2016 ◽  
Vol 850 ◽  
pp. 444-451
Author(s):  
Shu Liang Wang ◽  
Lu Jiang Zhou ◽  
Jia Lian Li ◽  
Xiao Hong Wang ◽  
Yuan Hua Lin ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Intermetallic Compounds ◽  
Binary Systems ◽  
Ternary Systems ◽  
Free Energies ◽  
Gibbs Energies ◽  
Solution Models ◽  
New Type ◽  
Free Solder ◽  
Kister Equation

With available melting point and hardness, the Bi-based filler alloy is considered as one choice of high-temperature Pb-free solder. Phase diagram can play an important role in the design of new type of Pb-free solder.In the present work, the thermodynamic assessments of the Au-Nd and the Au-Lu binary systems have been carried out by the Calculation of Phase Diagram (CALPHAD) method based on the available experimental data. The Gibbs free energies of the solution phases were described by subregular solution models with the Redlich-Kister equation, and those of the intermetallic compounds were described by sublattice models. A set of self-consistent and reasonable thermodynamic parameters is obtained for the binary systems, which describes the Gibbs energies of the solution phases and the intermetallic compounds phases. Additionally, combined the reported Bi-Au, Bi-Lu and Bi-Nd binary systems, the thermodynamic database of the Bi-Au-Lu and the Bi-Au-Nd ternary systems have been developed, which will provide important thermodynamic information for the phase equilibria of the multicomponent Bi-based alloy systems.

Chemical stability of CuInS2 in oxygen at 298 K

1997 ◽  
Vol 12 (2) ◽  
pp. 355-363 ◽  
Author(s):  
J. Grzanna ◽  
H. Migge
Keyword(s):  
Phase Diagram ◽  
Crystal Growth ◽  
Phase Equilibria ◽  
Chemical Stability ◽  
Quaternary System ◽  
Ternary Systems ◽  
Free Energies ◽  
Two Phase ◽  
Partial Pressures

A thermochemical analysis is performed in the quaternary system Cu–In–S–O at 298 K, including the respective four ternaries. The Cu–In phase diagram is updated with respect to the new experimental as well as to the new thermochemical results in the literature. Free energies of In6S7, In2.8S4, CuIn2, and Cu2In2O5 have been estimated. Consistent sets of data are used for the calculations of the ternary systems with the program thermo, and the results are used to calculate the quaternary tetrahedron Cu–In–S–O with the program thermoq; the algorithm is given. Twelve quaternary two-phase equilibria have been found. They are used to calculate predominance area diagrams of the quaternary system with the program stadiaq for different oxygen partial pressures. The algorithm of this program is given. From these diagrams it becomes obvious that CuInS2 is unstable in air and even in UHV systems and should react to form In2(SO4)3 and Cu2S at oxygen pressures larger than log p (pascal) = −51.5. The results are useful for research in fields such as oxidation and crystal growth of CuInS2 and for development of processes for producing this compound.

Thermodynamic Study of Ag-Au-Gd, Tb Ternary Systems

2015 ◽  
Vol 814 ◽  
pp. 313-318 ◽  
Author(s):  
Jia Lian Li ◽  
Shu Liang Wang ◽  
Lu Jiang Zhou ◽  
Xiao Hong Wang ◽  
Yuan Hua Lin ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Phase Diagrams ◽  
Binary Systems ◽  
Lattice Models ◽  
Ternary Systems ◽  
Calculated Phase Diagram ◽  
Thermodynamic Database ◽  
Filler Alloy ◽  
Free Energies ◽  
Significant Information

The addition of the rare earth elements into the Ag-based filler alloy, which is typical and important, can control and eliminate the negative effect of impurity elements, and furthermore, it improves the spreading property of the Ag-based filler alloy. Phase diagram provides an important direction for materials design of the Ag-based filler alloy. Thus it is necessary to investigate the phase diagrams and construct the thermodynamic database. On the basis of this background, thermodynamic assessments of the Au-Gd, Tb binary systems were carried out by using the CALPHAD (Calculation of Phase Diagrams) method based on the experimental data including thermodynamic properties and phase equilibrium. The Gibbs free energies of the solution phases were described by sub-regular solution models with the Redlich-Kister equation, while all of the intermetallic compounds were described by sub-lattice models. A consistent set of thermodynamic parameters was derived from describing the Gibbs free energies of each solution phase and intermetallic compound. The calculated phase diagram achieved consistency with the available experiments. Then combined with the assessed relevant binary systems, the Ag-Au-Gd, Tb ternary systems have been predicted. The thermodynamic database of these ternary systems has been developed to present the significant information for the design of Ag-based filler alloys.

Prospects for producing hydrogen-ammonia fuel using lithium-aluminum amide

2021 ◽  
Vol 64 (1) ◽  
pp. 78-89
Author(s):  
D.V. Schur ◽  
◽  
S.Yu. Zaginainchenko ◽  
Afer Veziroglu ◽  
T.N. Veziroglu ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Phase Transformation ◽  
Statistical Theory ◽  
Equilibrium State ◽  
Temperature Dependence ◽  
Hydrogen Concentration ◽  
Lithium Aluminum ◽  
Free Energies ◽  
Thermodynamic Equilibrium State ◽  
Pressure Hydrogen

A statistical theory of the phase transformation of lithium aluminum amide with the release of ammonia is developed. The free energies of the phases are calculated, their dependence on temperature, pressure, hydrogen concentration and energy parameters is established. The phase diagram is built. The equations of the thermodynamic equilibrium state are calculated. Investigated isoprocesses in phases. The coefficients of rectangularity and uniformity of isotherms are obtained. A feature of the temperature dependence of the concentration of hydrogen in phases is established.

Solid State Electrochemical Study of Phase Equilibria and Thermodynamics of the Ternary System Y-Fe-O at Elevated Temperatures

1979 ◽  
Vol 34 (4) ◽  
pp. 430-436 ◽  
Author(s):  
W. Piekarczyk ◽  
W. Weppner ◽  
A. Rabenau
Keyword(s):  
Phase Diagram ◽  
Solid State ◽  
Ternary System ◽  
Phase Equilibria ◽  
Elevated Temperatures ◽  
Free Energies ◽  
Ternary Compounds ◽  
Temperature Range ◽  
The Third ◽  
Galvanic Cell Technique

A solid state galvanic cell technique has been employed to determine the phase diagram of the ternary system Y-Fe-O in the temperature range from 900 to 1250 °C. Only electrical quantities need to be measured and the samples do not have to be quenched. YFeO3 and Y3Fe5O12 exist over the entire temperature range, whereas the third ternary compound YFe2O4-x is only thermodynamically stable above 1010 ± 9 °C. Above 1078 ± 15 °C YFe2O4-x comes into equilibrium with Y2O3.With the same experimental arrangement the standard Gibbs free energies of formation ⊿G f0 of the ternary compounds YFeO3, Y3Fe5O12 and YFe2O4 have been determined to be -1366.0 + 0.2525 X T kJ/mol (1173 ≦ T [K] ≦ 1523), - 4912.2 +0.9990 X T kJ/mol (1173≦T[K] ≦ 1523) and -1615.9 + 0.3068 x T kJ/mol (1283≦T[K] ≦ 1523) as functions of the temperature, respectively

scholarly journals Free energy calculations for rings and chains formed by dipolar hard spheres

Soft Matter ◽  
2017 ◽  
Vol 13 (43) ◽  
pp. 7870-7878 ◽  
Author(s):  
Michela Ronti ◽  
Lorenzo Rovigatti ◽  
José M. Tavares ◽  
Alexey O. Ivanov ◽  
Sofia S. Kantorovich ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Free Energy ◽  
Hard Spheres ◽  
Numerical Approach ◽  
Free Energy Calculations ◽  
Free Energies ◽  
Energy Calculations

A numerical approach to calculate the free energies of DHS particles in chains and rings, exploring the unknown low-T region of the phase diagram of DHS.

scholarly journals Ab Initio Calculations of Ordered Intermetallic Phase Equilibria

1988 ◽  
Vol 133 ◽  
Author(s):  
M. Sluiter ◽  
D. De Fontaine ◽  
X. Q. Guo ◽  
R. Podloucky ◽  
A. J. Freeman
Keyword(s):  
Phase Diagram ◽  
Phase Equilibria ◽  
Ab Initio ◽  
First Principles ◽  
Intermetallic Phase ◽  
Electronic Structure Calculations ◽  
Free Energies ◽  
Metastable Structures ◽  
Ordered Intermetallic ◽  
Structure Calculations

ABSTRACTGeneral procedures for computing alloy phase equilibria from ab initio electronic structure calculations are reviewed and applied to the Al-Li phase diagram. Free energies were calculated by the cluster variationm.method (CVM) in the tetrahedron approximation for the fcc and bcc lattices and ordered superstructures. Input was provided by first principles FLAPW calculations. The computed phase diagram for both stable and metastable structures agrees remarkably well with the experimental one.

A Kinetic Phase Diagram for Ultrathin Film Ni/Si(111): Auger Lineshape Results

1989 ◽  
Vol 148 ◽  
Author(s):  
P. A. Bennett ◽  
J. R. Butler ◽  
X. Tong
Keyword(s):  
Phase Diagram ◽  
Reaction Rate ◽  
Single Phase ◽  
Solid Phase ◽  
Bulk Diffusion ◽  
Auger Spectroscopy ◽  
Ultrathin Film ◽  
Solid Phase Epitaxy ◽  
Free Energies ◽  
Diffusion Limited

ABSTRACTWe have used Auger spectroscopy to monitor chemical reactions during solid phase epitaxy by contact reaction in the Ni/Si(ll1) ultrathin film system. We show that coexisting phases may be separated by numerically fitting the composite Si LVV lineshape using a linear combination of single phase “fingerprint” spectra. Sytematic measurements of coverage and temperature conditions are compiled into a kinetic phase diagram. Comparison with conventional (1000Å) thin film data suggest that the reactions forming Ni2Si and NiSi at > 20 Å thickness are bulk diffusion limited, while surface diffusion dominates at lower coverage. On the other hand, the formation of NiSi2 appears to be nucleation limited at all coverages, with dramatic variations in reaction rate with film thickness. This is discussed in terms of a competition between surface and bulk free energies.

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