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The equilibrium T − x space of the Ag-Ga-Te-AgBr system in the part Ag2Te-GaTe-Te-AgBr-Ag2Te below 600 K has been divided into separate phase regions using the electromotive force (EMF) method. Accurate experimental data were obtained using the following electrochemical cells (ECs): (−) IE | NE | SSE | R{Ag+} | PE | IE (+), where IE is the inert electrode (graphite powder), NE is the negative electrode (silver powder), SSE is the solid-state electrolyte (glassy Ag3GeS3Br), PE is the positive electrode, R{Ag+} is the region of PE that is contact in with SSE. At the stage of cell preparation, PE is a non-equilibrium phase mixture of the well-mixed powdered compounds Ag2Te, GaTe, Ga2Te3, AgBr, and tellurium, taken in ratios corresponding to two or three different points of interest for each of the phase regions. The equilibrium set of phases was formed in the R{Ag+} region at 600 K for 48 h with the participation of the Ag+ ions. Silver cations, displaced for thermodynamic reasons from the NE to the PE of ECs, acted as catalysts, i.e., small nucleation centers of equilibrium phases. The spatial position of the established phase regions relative to the position of silver was used to express the overall reactions of synthesis of the binary Ga2Te5, Ga7Te10, Ga3Te4, ternary AgGa5Te8, and quaternary Ag3Ga10Te16Br, Ag3Ga2Te4Br, Ag27Ga2Te12Br9 compounds in the PE of ECs. The values of the standard thermodynamic functions (Gibbs energies, enthalpies, and entropies) of these compounds were determined based on the temperature dependencies of the EMF of the ECs. [ABSTRACT FROM AUTHOR]

Thermodynamic properties of titanium are evaluated to 3700 K. Selected values include an enthalpy of sublimation value of 472.6 ± 1.0 kJ/mol at 298.15 K and a boiling point at one atmosphere pressure of 3618 K. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of chromium have been evaluated to 3000 K. Selected values include an enthalpy of sublimation of 396.8 ± 4.0 kJ/mol at 298.15 K and a boiling point at one atmospheric pressure (1.01325 bar) of 2987 K. The value for the melting point of chromium is recommended as 2135 ± 5 K on the temperature scale ITS-90. [ABSTRACT FROM AUTHOR]

The Redlich–Kister polynomial equation was employed to optimize the temperature-dependent interaction parameters for excess Gibbs energy of mixing of the Cd-Na binary liquid alloy, utilizing experimental data on enthalpy and excess entropy of mixing. These parameters were used to evaluate thermodynamic properties such as Gibbs energy of mixing, enthalpy of mixing, and component activity in alloys at 673 K, 773 K, and 873 K. Structural properties like concentration fluctuations in the long wavelength limit and Warren–Cowely short range order parameter were also studied using these parameters. The Butler equation with interaction energy parameters was used to study the surface tension and surface composition of the alloys at the aforementioned temperatures. Experimental results confirmed the predicted values of excess Gibbs energy of mixing, enthalpy of mixing, and activity of mixing. Additionally, the excess Gibbs energy of mixing value changed from positive to negative with increased Cd compositions in the alloy. The enthalpy of mixing of the alloys was negative for all compositions. The concentration fluctuation in the long wavelength limit shifted toward optimal values at high temperatures. The surface tension of the alloys increased non-linearly with the bulk composition of Cd. [ABSTRACT FROM AUTHOR]

The thermodynamic description of pure Fe was re-assessed using updated third generation Calphad models and taking into account the most recent theoretical data. In the present re-assessment, a critical evaluation was performed for the magnetic properties of the fcc and hcp phases yielding different descriptions from those accepted in the SGTE database. The selected magnetic properties enable us to model the thermodynamic properties of fcc satisfactorily without using the magnetic two-state model. A new method was applied to extrapolate the thermodynamic data for the solid phases, i.e. a single Gibbs energy expression is used for the entire temperature range for the bcc, fcc and hcp phases. The description of the liquid phase was re-evaluated following a recent suggestion on estimating the electronic heat capacity coefficient for the liquid phase. Overall, the present Calphad description can reproduce the selected experimental and theoretical data well. [ABSTRACT FROM AUTHOR]

The phase equilibria in the lime rich part of the CaO-Al2O3-B2O3 ternary system were investigated by thermodynamic modeling and key experiments. Three ternary compounds, CaAl2B2O7 (CAB), Ca2Al2B2O8 (C2AB) and Ca2Al2B6O14 (C2AB3), are reported in the literature and their thermodynamic properties were calculated using Density Functional Theory and lattice dynamics theory. Partial isothermal sections of the lime rich part of the CaO-Al2O3-B2O3 ternary system were investigated at 950 and 1020 °C using solid state reactions and x-ray diffraction on 14 selected samples. The observed results confirm the available experimental data from the literature. Based on thermal analysis using differential scanning calorimetry, the Ca3Al2O6-CaB2O4 and CaAl2O4-CaB2O4 T-x sections as well as a tentative partial liquid surface of the lime rich part were constructed. [ABSTRACT FROM AUTHOR]

The CAlculation of PHAse Diagram (CALPHAD) technique is used in the critical remodeling of the Cd–Gd system. On the basis of a new experiment in literature, the excess Gibbs energies of the solution phase expression (liquid, bcc, and hcp_A3) are described using the Redlich–Kister equation. Intermetallic compounds (α-Cd2Gd, β-Cd2Gd, and Cd45Gd11), which exhibit a homogeneity range, are treated as a two-sublattice model. Four compounds (Cd3Gd, Cd58Gd13, Cd6Gd, and Cd8Gd) are treated as stoichiometric compounds. Two Calphad-type thermodynamic descriptions are developed for the CdGd and bcc. Model I is to model the compound CdGd and bcc-Gd separately. Model II is to use the formula (Cd,Gd)0.5(Cd,Gd)0.5(Va)3 to describe the compound CdGd with a CsCl-type structure (B2) and cope with the disorder–order transition from bcc-A2 to bcc-B2. The present work displays that two eutectic reactions, five peritectic reactions, one peritectoid reaction, one eutectoid reaction, one polymorphic transformation, and one congruent reaction are observed in the Cd–Gd system. [ABSTRACT FROM AUTHOR]

Phase relations in the Ga-Ge-Sb ternary system were investigated experimentally, using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and differential scanning calorimetry (DSC). Nine ternary samples were prepared by melting of pure elements under an argon atmosphere. The compositions of the prepared alloys were situated along three cross sections with the molar ratios Ga:Ge = 1, Ga:Sb = 1 and Ge:Sb = 1. Phase transition temperatures of the investigated samples were determined using DSC. The microstructure of the samples was analyzed using a scanning electron microscope with EDS and co-existing phases were identified. Binary thermodynamic data from literature, successfully used for phase diagram calculations of binary Ga-Ge, Ga-Sb and Ge-Sb systems, were used for the prediction of phase equilibria in the ternary Ga-Ge-Sb system. The activities of Ga in the liquid phase were calculated using the Redlich-Kister-Muggianu model and compared with experimental data reported in the literature. The liquidus projection, invariant equilibria and three vertical sections of the Ga-Ge-Sb ternary system were calculated and compared with the experimental results and a good agreement was observed. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of tungsten have been evaluated to 6200 K. Selected values include an enthalpy of sublimation of 855 ± 5 kJ/mol at 298.15 K and a boiling point at one atmosphere pressure of 6101 K. [ABSTRACT FROM AUTHOR]

Equilibria among the slag, matte and metal phases in the Cu-Fe-O-S-Si system are critically assessed using thermodynamic modeling. The relationships among matte grade, temperature, partial pressure of SO2, Fe/SiO2 in the slag, and the copper concentration in the slag are described by the model, as well as the concentrations of other elements in all phases. A thermodynamic database is created, which can be used for understanding and improving the pyrometallurgical production of copper. An extensive experimental dataset includes the most recent results obtained by the equilibration/quenching/EPMA analysis technique. These data allow to distinguish the physical entrainment of the matte and solid phases in the slag from chemical solubility. As a result, it is possible to describe the copper solubility in the slag with high accuracy and establish the relationship between copper and sulfur in the slag. The thermodynamic database of the present study is consistent with previously reported thermodynamic evaluations of binary, ternary and quaternary subsystems. The slag phase is modeled using the two-sublattice modified quasichemical model in the quadruplet approximation. The matte and metal liquid phases are modeled as one solution using the single-sublattice modified quasichemical model in the pair approximation. [ABSTRACT FROM AUTHOR]

Partial and integral enthalpies of mixing of ternary Li-Pb-Sb alloys were measured at 923 and 1023 K with drop calorimetry. In total 12 sections were studied of fixed molar ratios of Li to Pb equal to 1/9, 1/3, 2/3, 1, 3/2, 3, Pb to Sb equal to 3/1, 1, 1/3 and Li to Sb equal to 1/4, 2/3, 1. The measurements were performed by consecutive dropping solid metal samples (Li, Pb or Sb) from ambient temperature into calorimeter chamber. In the first step calibration was performed, in the second binary starting alloy was formed, and finally enthalpies of liquid ternary alloys were measured. Integral enthalpies of mixing are negative in the whole concentration range studied, and tend to a minimum associated with a minimum in Li-Sb system. [ABSTRACT FROM AUTHOR]

Triangulation of the Ag-Hg-Se-I system in the vicinity of quaternary phase AgHgSeI was performed by differential thermal analysis, X-ray diffraction and electromotive force (EMF) methods. The spatial position of the phase region AgHgSeI-Se-HgI regarding the figurative point of silver was used to write the chemical reaction of formation of AgHgSeI. The EMF measurements were carried out by applying an electrochemical cell: (-) C|Ag|AgGeS glass|AgHgSeI, HgI, Se|C (+), where C is graphite and AgGeS glass is the fast purely Ag ions conducting electrolyte. The linear dependence of the EMF of the electrochemical cell on temperature was used to determine the standard thermodynamic values of AgHgSeI for the first time. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of niobium have been evaluated to 5200 K. Selected values include an enthalpy of sublimation of 732 ± 10 kJ/mol at 298.15 K and a boiling point at one atmosphere pressure of 5197 K. [ABSTRACT FROM AUTHOR]

Triangulation of the Ag-Pb-Ge-S system in the AgGeS-Ge-GeS-PbS part was performed by differential thermal analysis, XRD and EMF methods. The serpentine-like shape of the concentration variation of Gibbs partial energy of silver $$- \Delta \overline{G}_{\text{Ag}}^{ \circ }$$ in the alloys of the AgGeS-PbS system in the AgGeS-(AgGeS)(PbS) part at T = const ( T = 518, 538, 556 K) is the consequence of the kinetically metastable state of the alloys of the limited solid solution range AgGeS-(AgGeS)(PbS). According to the principles of continuity and correspondence, the $$- \Delta \overline{G}_{\text{Ag}}^{ \circ }$$ extremum of the alloy (AgGeS)(PbS) determines the composition of the intermediate phase AgPbGeS of the equilibrium system AgGeS-PbS. Potential-forming processes were performed in electrochemical cells (ECCs) of the type C|Ag|AgGeS glass| D|C (where C are current (graphite) electrode; Ag and D are the electrodes of ECCs; AgGeS glass is a membrane with ionic Ag conductivity; D are silver-containing single-, two- and four-phase alloys). Linear EMF dependences of cells in the 510-560 K range were used to calculate integral values of the thermodynamic functions of saturated solid solutions of the phases AgPbGeS, AgPbGeS, AgPbGeS (the composition of AgPbGeS from the PbS side). A significant excess of integral standard energy Gibbs $$\Delta_{\text{f}} G_{{298,\;{\text{Ag}}_{ 6. 4 8} {\text{Pb}}_{ 0. 1 9} {\text{Ge}}_{ 0. 8 1} {\text{S}}_{ 5. 0 5} }}^{\circ}$$ = (−401.8 ± 1.5) kJ mol over the values of $$\Delta_{\text{f}} G_{298,\;{\text{A}}{{\text{g}}_{\text{8}}}{\text{Ge}}{{\text{S}}_{\text{6}}}}^{\circ}$$ = (−345.0 ± 2.2) kJ mol and $$\Delta_{\text{f}} G_{{298,\;{\text{PbS}}}}^{\circ}$$ = (−96.994 ± 0.005) kJ mol is considered as the confirmation of the existence of a quaternary phase in the equilibrium system AgGeS-PbS. The contribution of the entropy factor $$T\Delta_{\text{f}} S_{{298,\;{\text{Ag}}_{ 6. 4 8} {\text{Pb}}_{ 0. 1 9} {\text{Ge}}_{ 0. 8 1} {\text{S}}_{ 5. 0 5} }}^{\circ}$$ into the value of $$\Delta_{\text{f}} G_{{298,\;{\text{Ag}}_{ 6. 4 8} {\text{Pb}}_{ 0. 1 9} {\text{Ge}}_{ 0. 8 1} {\text{S}}_{ 5. 0 5} }}^{\circ}$$ exceeds 33%. [ABSTRACT FROM AUTHOR]

This work has its roots in a long-term theoretical research line aimed at developing a complete database with structural, thermodynamic, cohesive and elastic properties of the intermetallic compounds (ICs) of the type MeX where Me = Cu, Ni and X = In, Sn and Sb. The paper reports the results of an ab initio study of various phases occurring in the Ni-Sb phase diagram, viz., the low-temperature NiSb (orthorhombic oP8), the high-temperature NiSb (cubic cF16), NiSb (monoclinic mC28), NiSb (hexagonal hP4) and the NiSb (orthorhombic oP6) compounds. The molar volume, bulk modulus and its pressure derivative, the electronic density of states (DOS) and the energy of formation from the elements of these compounds are calculated ab initio using the relativistic projected augmented wave (PAW) method implemented in the VASP code. The Local Density Approximation of Ceperley and Alder and the Generalized Gradient Approximation due to Perdew and Wang are adopted to treat the exchange and correlation energies. Detailed comparisons between the current and previously reported theoretical and experimental values are reported. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of vanadium have been evaluated to 3700 K. Selected values include an enthalpy of sublimation of 515 ± 2 kJ/mol at 298.15 K and a boiling point at one atmosphere pressure of 3694 K. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of beryllium have been evaluated up to 2800 K. A further evaluation is justified by the inclusion of not only new specific heat measurements at low temperature but also new enthalpy measurements at high temperature which lead to a reassessment of the enthalpies and entropies of transition and fusion. Selected values include an enthalpy of sublimation of 324 ± 5 kJ/mol at 298.15 K and a boiling point at one atmosphere pressure of 2745 K. [ABSTRACT FROM AUTHOR]

The solution calorimetry and electromotive force methods were used for the study of the mixing enthalpy and partial excess Gibbs energy of the Al-Li-Zn liquid solutions. Calorimetric investigations were conducted for solutions with the ratio of X / X and X / X = 0.8/0.2 and at the temperatures of 942 and 978 K, respectively. The electromotive force studies were performed at two temperatures: 873 and 923 K by the titration technique and for dilute solutions. Based on the data of the mixing enthalpy change and the partial excess Gibbs energy of Li available in the literature, together with that obtained in these studies, the ternary interaction parameters were elaborated. The comparative analysis of the experimental mixing enthalpy change generally showed a good agreement with the values calculated based on different models. The observed deviations between the experimental and the calculated values were, for most of the experimental data, lower than 1 kJ/mol. The experimental partial excess Gibbs energy of Li showed a satisfactory agreement with that modeled on the basis of the ternary parameters elaborated in this work. [ABSTRACT FROM AUTHOR]

The two domain model of Se-Te liquid is developed further than heretofore. Explicit equations are obtained for the excess Gibbs energy of mixing, the chemical potentials, the enthalpy of mixing, the relative constant pressure heat capacity, and the partial and total pressures. A generally satisfactory fit is obtained for the experimental activity of Te and enthalpy of mixing at 733 K, the relative heat capacity as a function of temperature, and for the total pressure for 99, 60, and 27 at.% Se between about 780 and 1130 K. This is done while leaving unchanged the site fraction of H or (Te-like) and L (or Se-like) domains previously used to fit a number of physical properties. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of gold have been evaluated to 3200 K. Selected values include an enthalpy of sublimation of 368.4 ± 1.1 kJ·mol for the monatomic gas at 298.15 K, a dissociation enthalpy D of 221.5 ± 0.8 kJ·mol for the diatomic gas species at absolute zero and a derived equilibrium boiling point of 3131 K at one atmosphere pressure. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of silver have been evaluated to 2700 K. Selected values include an enthalpy of sublimation of 284.8 ± 0.9 kJ/mol for the monatomic gas at 298.15 K, a dissociation enthalpy D of 157.7 ± 2.2 kJ/mol for the diatomic gas species at absolute zero, and a derived equilibrium boiling point of 2433 K at one atmosphere pressure. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of copper have been evaluated to 2900 K. Selected values include an enthalpy of sublimation of 337.2 ± 1.7 kJ/mol for the monatomic gas at 298.15 K, a dissociation enthalpy D of 192.0 ± 2.0 kJ/mol for the diatomic gas species at absolute zero and a derived equilibrium boiling point of 2843 K at one atmosphere pressure. [ABSTRACT FROM AUTHOR]

The Fe-O-S system has been assessed over the whole composition range to produce a self-consistent set of thermodynamic properties of all condensed phases from 298 K to above the liquidus temperatures at ambient pressure. The liquid phase from metallic liquid to sulfide melt to oxide melt is described by a single model developed within the framework of the quasichemical formalism. The model reflects the existence of strong short-range ordering in oxide, sulfide and oxysulfide liquid. Two ranges of maximum short-range ordering in the Fe-O system at approximately FeO and FeO compositions are taken into account. Parameters of thermodynamic models have been optimized to reproduce all available thermodynamic and phase equilibrium data. The thermodynamic modeling of the Fe-O-S system performed in the present study is of particular importance for the description of the solubility of oxygen in matte. [ABSTRACT FROM AUTHOR]

By using the calculation of phase diagrams (CALPHAD) method, the thermodynamic assessments of the Sc-M (M: Cr, Gd, Mo, W and Zr) binary systems were carried out based on the available experimental data including thermodynamic properties and phase equilibria. Gibbs free energies of the liquid, hcp and bcc phases in the Sc-M (M: Cr, Gd, Mo, W and Zr) binary systems were modeled by the substitutional solution model. An agreement between the present calculated results and experimental data was obtained. [ABSTRACT FROM AUTHOR]

Critical evaluation and optimization of all available phase diagrams and thermodynamic data for the Mn-RE (RE = Tb, Dy, Ho, Er, Tm, and Lu) systems has been conducted to obtain reliable thermodynamic functions of all the phases in the systems. Key experiments for the Mn-Dy system were performed using DSC and solution calorimeter. In the thermodynamic modeling, it is found that the Mn-RE systems show systematic changes in the phase diagrams and thermodynamic properties such as enthalpy of mixing in liquid state in the order of periodic number in the lanthanide series. The systematic thermodynamic modeling approach for RE elements allow to resolve inconsistencies in the experimental data and estimate unknown thermodynamic properties and phase equilibria of Mn-RE system. [ABSTRACT FROM AUTHOR]

The phase equilibria of the Bi-Cu-Zn ternary system has been firstly and comprehensively investigated by electron probe microanalyzer (EPMA) with equilibrated alloys. Two isothermal sections of the Bi-Cu-Zn ternary system at 500 and 650 °C were determined. Based on the experimental data of phase equilibria, the Bi-Cu-Zn ternary system was also thermodynamically optimized using the Calculation of Phase Diagrams (CALPHAD) method. The experimental result shows that Bi is almost insoluble in the Cu-Zn binary compounds and (Cu) phase. It is found that the critical temperatures of the miscibility gaps in the Bi-Cu and Bi-Zn binary systems gradually increase with the increasing of the third element Zn or Cu additions. Moreover, the composition range of the liquid miscibility gap gradually reduces with the temperature increasing. [ABSTRACT FROM AUTHOR]

Standard enthalpies of formation of ternary phases in the Cu-Ni-Sn system were determined along sections at 25, 41 and 45.5 at.% Sn applying tin solution drop calorimetry. Generally, the interaction of Ni with Sn is much stronger than that of Cu with Sn. Along all sections the enthalpy of formation changes almost linearly with the mutual substitution of Cu and Ni within the respective homogeneity ranges. Thus no additional ternary interaction promoting the formation of further Cu-Ni-Sn phases can be assumed. The results are discussed and compared with literature values relevant to this system. [ABSTRACT FROM AUTHOR]

New enthalpy measurements above 2000 K have resulted in a complete reassessment and revision of the high temperature thermodynamic properties of hafnium. Values have been assessed to 4900 K and include a selected enthalpy of sublimation at 298.15 K of 621 ± 5 kJ/mol and a derived boiling point of 4850 K at one atmosphere pressure. A comparison is given between selected properties of the Group 4 elements to consider periodic trends. [ABSTRACT FROM AUTHOR]

The electromotive force (EMF) of galvanic cells with β-alumina solid electrolyte was measured to determine the phase relations and thermodynamic properties of the Na-Si binary system below 800 °C. Na was added by coulometric titration to cells containing known amounts of silicon. The galvanic cells sealed with Corning 1720 Kovar glass had unpredictable lifetimes, lasting from several days to less than one reading. A new ceramic seal consisting of NaO-AlO eutectic was developed which allowed high temperature EMF measurements up to 800 °C. The solubility of Si in molten Na was determined to be very limited. Properties of the NaSi and NaSi compounds were derived from the EMF measurements. Differential thermal analysis (DTA) experiments were carried out to determine the onset temperature of phase changes. [ABSTRACT FROM AUTHOR]

The phase equilibria of the Cr-Hf-Ti ternary system has been firstly investigated by electron probe micro-analyzer, x-ray diffraction and differential scanning calorimetry on equilibrated alloys. Three isothermal sections of the Cr-Hf-Ti ternary system at 1100, 1200 and 1300 °C were determined. Meanwhile, this ternary system was also thermodynamically optimized using the calculation of phase diagrams method. The calculated result replies that the existing temperature range of the C15 (CrHf) increased due to addition of the third element Ti. [ABSTRACT FROM AUTHOR]

Hassam et al. recently reported a thermodynamic assessment of the binary Pb-Sb system. Experimental data reveal that the properties of liquid lead-antimony alloy differ slightly from an ideal solution. However, Hassam et al. utilized a non-regular model with six parameters for liquid description, which seems to be not reasonable and can result in bad behavior of the extrapolation of the calculation into areas not covered by the experiments. In this work, a new thermodynamic description of the binary Pb-Sb system was proposed with good agreement between experimental data and predicted results. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of the HoRhO were determined in the temperature range from 900 to 1300 K by using a solid-state electrochemical cell incorporating calcia-stabilized zirconia as the electrolyte. The standard Gibbs free energy of formation of orthorhombic perovskite HoRhO, from HoO with C-rare earth structure and RhO with orthorhombic structure, can be expressed by the equation;Using the thermodynamic data of HoRhO and auxiliary data for binary oxides from the literature, the phase relations in the Ho-Rh-O system were computed at 1273 K. Thermodynamic data for intermetallic phases in the binary Ho-Rh were estimated from experimental enthalpy of formation for three compositions from the literature and Miedema's model, consistent with the phase diagram. The oxygen potential-composition diagram and three-dimensional chemical potential diagram at 1273 K, and temperature-composition diagrams at constant oxygen partial pressures were computed for the system Ho-Rh-O. The decomposition temperature of HoRhO is 1717(±2) K in pure O and 1610(±2) K in air at a total pressure p = 0.1 MPa. [ABSTRACT FROM AUTHOR]

In this work, we will be reviewing and assessing the heat capacity of CaO-SiO compounds at constant pressure ( C) as a function of temperature. While there is a large amount of literature available for CaSiO high and low temperature compounds, literature for the remaining compounds CaSiO, CaSiO and CaSiO is scarce. Whereas most of the reports in the literature concerning the heat capacities ( C) of CaSiO are in agreement, some of them do deviate (e.g., for the liquid). Experimental determinations of the heat capacities of the CaSiO and CaSiO phases are particularly scarce. Most of the data were therefore taken from thermodynamic assessments. For CaSiO there are experimental and modelling results which show some slight deviation in the low temperature part. This review provides the current status of the research on heat capacity of compounds in the CaO-SiO system. [ABSTRACT FROM AUTHOR]

The measurement of electromotive force (EMF) of concentration cells was applied to obtain zinc activity in ternary liquid Sb-Sn-Zn alloys in a Zn|(KCl-LiCl) + ZnCl|(Sb-Sn-Zn) galvanic cell. The measurements were carried out at temperatures from 723 up to 943 K for different Zn concentrations X and for five constant ratios of Sn to Sb mole fractions, which were 1/3, 1, 3, 4 and 9. It was found out, that with increasing Sn concentration in the ternary alloys, the activity of Zn grew reaching the highest values for alloys of ratio Sn/Sb = 9 out of the ternary alloys examined. The observed straight-line changes of EMF matched a EMF = A + B * T equation. The calculated coefficients served to obtain the activities and excess Gibbs free energy for selected temperatures 823 and 923 K. [ABSTRACT FROM AUTHOR]

By using the calculation of phase diagrams (CALPHAD) method, the thermodynamic assessments of the Bi-Tb and Bi-Y systems were carried out based on the available experimental data including thermodynamic properties and phase equilibria. Gibbs free energies of the liquid, hcp, bcc, and rhombohedral phases in the Bi-Tb and Bi-Y systems were modeled by the substitutional solution model, and the intermetallic compounds (BiTb, BiTb, αBiTb, βBiTb, BiY, and BiY phases) in these two binary systems were described by the sublattice model. An agreement between the present calculated results and experimental data was obtained. [ABSTRACT FROM AUTHOR]

The high temperature heat capacity, Gibbs energy of formation, and standard enthalpy and entropy of formation at 298 K are combined with thermodynamic data for Cd and revised data for Te to provide an internally consistent data set for CdTe(c). Equations are given for the Gibbs energy of formation from Cd(g) and Te2(g) and from the solid or liquid elements as a function of temperature. These give values similar to those used before. However, the derived enthalpy and entropy of formation are significantly different due to a revised heat capacity for CdTe(c). The standard enthalpy and entropy of formation at 298.15 K from the gases are −293262 J/mol and −200.593 J/mol K, respectively. From the solid elements they are −100270 and −4.5334. [ABSTRACT FROM AUTHOR]

The phase diagram of the DyBr3-LiBr binary system was derived from DSC measurements. It exhibits two eutectics and has two stoichiometric compounds. The first compound, Li3DyBr6, melts congruently at 803 K. The second one, Li6DyBr9 decomposes in the solid state at 656 K. The composition of the two eutectic mixtures, x(DyBr3) = 0.156 and 0.321, respectively, was determined by the Tamman method. The respective eutectic temperatures are 787 and 791 K. The electrical conductivity of Li3DyBr6 compound was measured in the liquid and solid phase. It was found to be a solid electrolyte with a high electrical conductivity at around room temperature. Some additional electrical conductivity measurements performed on solid samples confirmed the existence of Li6DyBr9. [ABSTRACT FROM AUTHOR]

The Al-Mo and Al-Fe-Mo systems were critically assessed using the CALPHAD technique. The solution phases (liquid, fcc and bcc) were described by a substitutional solution model. The non-stoichiometric compound AlMo3 was described by a two-sublattice model (Al,Mo)(Al,Mo)3 in the Al-Mo binary system and (Al,Fe,Mo)(Al,Fe,Mo)3 in the Al-Fe-Mo ternary system. Other compounds Al63Mo37, Al8Mo3, Al3Mo, Al4Mo, Al17Mo4, Al22Mo5, Al12Mo and Al5Mo in the Al-Mo system were treated as stoichiometric compounds in the binary system and as line compounds Al m(Fe,Mo) n in the Al-Fe-Mo ternary system. The compounds μ and Fe2Mo in the Fe-Mo system were treated as (Al,Fe)7Fe2(Fe,Mo)4 and (Fe,Mo)2(Al,Mo) in the Al-Fe-Mo system, respectively. Compounds Al5Fe4, Al2Fe, Al5Fe2 and Al13Fe4 in the Al-Fe system were treated as (Al,Fe,Mo), Al2(Fe,Mo), (Al,Fe)5(Al,Fe,Mo)2 and (Fe,Mo)0.235Al0.6275(Al,Va)0.1375 in the Al-Fe-Mo system, respectively. Ternary compounds τ1 and τ2 were treated as Al8(Al,Fe)Mo3 and (Al,Fe,Mo)(Va)3, respectively. A set of self-consistent thermodynamic parameters of the Al-Fe-Mo system was obtained. [ABSTRACT FROM AUTHOR]

The Al-Cr-Si system was critically assessed using the CALPHAD technique. The solution phases (liquid, bcc, fcc, and diamond) were described by a substitutional solution model. The compounds CrSi2, Cr3Si, AlCr2, αAl8Cr5, βAl8Cr5, Al4Cr, and Al11Cr2 in the Al-Cr-Si system were treated with sublattice models (Cr, Si)(Al, Cr, Si)2, (Cr, Si)3(Al, Cr, Si), (Al, Cr, Si)(Al, Cr)2, α(Al, Cr, Si)8(Al, Cr, Si)5, β(Al, Cr, Si)8(Al, Cr, Si)5, (Al, Si)4(Al, Cr), and (Al, Si)11(Al, Cr)2, respectively. The ternary intermetallic compounds τ1, τ2, and τ3 were treated as the formulae Al13Cr4Si4, Al9Cr3Si, and (Al,Si)11Cr4, respectively. A set of self-consistent thermodynamic description of the Al-Cr-Si system was obtained. [ABSTRACT FROM AUTHOR]

A thermodynamic database for nuclear materials, including U-Th, U-Pu, Th-Pu, and (U, Th, Pu)-X (X = Al, Co, Cr, Cu, Fe, Ga, Mg, Mn, Mo, Nb, Ni, Si, Ta, W, Zr) binary system has been developed by the Calculation of Phase Diagrams (CALPHAD) method. Thermodynamic parameters describing Gibbs free energies of different phases have been evaluated by optimizing experimental data on phase equilibria and thermodynamic properties. The present thermodynamic database can provide much-needed information such as stable and metastable phase equilibria, phase fractions, and various thermodynamic quantities that is important to the design of nuclear materials. This database is also an essential starting point to construct thermodynamic databases for the multicomponent systems. [ABSTRACT FROM AUTHOR]

The reduced Gibbs free energies of 30 types of pure organic compounds were calculated by using the Sanchez and Lacombe model (SL model). The calculated results for each pure organic compound are presented as both polynomial expressions and graphs. This database of pure organic compounds will provide basic information in thermodynamic assessments of binary, ternary and higher-order organic systems or organic-inorganic systems. [ABSTRACT FROM AUTHOR]

Based on the measurements of Alcock and Zador, Grundy et al. estimated an uncertainty of the order of ±5 kJ mol−1 for the standard Gibbs energy of formation of MnO in a recent assessment. Since the evaluation of thermodynamic data for the higher oxides Mn3O4, Mn2O3, and MnO2 depends on values for MnO, a redetermination of its Gibbs energy of formation was undertaken in the temperature range from 875 to 1300 K using a solid-state electrochemical cell incorporating yttria-doped thoria (YDT) as the solid electrolyte and Fe + Fe1 − δO as the reference electrode. The cell can be presented as Since the metals Fe and Mn undergo phase transitions in the temperature range of measurement, the reversible emf of the cell is represented by the three linear segments. Combining the emf with the oxygen potential for the reference electrode, the standard Gibbs energy of formation of MnO from α-Mn and gaseous diatomic oxygen in the temperature range from 875 to 980 K is obtained as: From 980 to 1300 K the Gibbs energy of formation of MnO from β-Mn and oxygen gas is given by: The new data are in excellent agreement with the earlier measurements of Alcock and Zador. Grundy et al. incorrectly analyzed the data of Alcock and Zador showing relatively large difference (±5 kJ mol−1) in Gibbs energies of MnO from their two cells with Fe + Fe1 − δO and Ni + NiO as reference electrodes. Thermodynamic data for MnO is reassessed in the light of the new measurements. A table of refined thermodynamic data for MnO from 298.15 to 2000 K is presented. [ABSTRACT FROM AUTHOR]

There are conflicting reports in the literature regarding solid solubility in the system RuO2-TiO2. To resolve this issue a few experiments were conducted in air at 1673, 1723, and 1773 K. The results show limited terminal solid solubility. There is an extended solid-state miscibility gap that intersects the decomposition curve for the RuO2-rich solid solution generating a peritectoid reaction at 1698 K. The measured equilibrium compositions of the solid solutions are used to develop a thermodynamic description of the oxide solid solution with rutile structure. Using the subregular solution model, the enthalpy of mixing can be represented by the expression, $$ \Delta H^{\rm M} /{\text{J}} \cdot {\text{mol}}^{{ - 1}} = X_{{{\text{TiO}}_{2} }} X_{{{\text{RuO}}_{2} }} {\left( {34,100X_{{{\text{TiO}}_{2} }} + 30,750X_{{{\text{RuO}}_{2} }} } \right)} $$ . The binodal and spinodal curves and T-X phase diagram in air are computed using this datum and Gibbs energy of formation of RuO2 available in the literature. The computed results suggest that equilibrium was not attained during solubility measurements at lower temperatures reported in the literature. [ABSTRACT FROM AUTHOR]

Thermodynamic properties of liquid, intermetallic, and quasi-crystalline phases of the Al-Mn system have been studied using two experimental techniques: integral effusion method and Knudsen-cell mass spectrometry. The functions of the liquid phase followed the laws of associated solution and indicated that three type complexes, AlMn, Al2Mn, and Al5Mn, existed in the melt. Phase equilibria calculated using this model and the intermetallic compounds thermodynamic characteristics were in close agreement with phase diagram. The decagonal phase was found to be more stable than the icosahedral quasi-crystals. The calculated enthalpies of the quasi-crystalline phase transformation to the equilibrium crystals were close to the available literature information. The difference between the Gibbs energies of both type quasi-crystals and equilibrium crystalline compositions increases with decreasing temperature. This evidence favors the conclusion that the stabilization of quasi-crystals is entropic in nature and that the quasi-crystalline state, similar to the glassy state in metallic alloys, is only intermediate between liquid and crystals. The conditions of the quasi-crystals formation were found to be closely related to a certain type of the chemical short-range order in liquid, namely to significant mole fraction of the Al5Mn associative complexes. [ABSTRACT FROM AUTHOR]

The Al2O3-SrO binary system has been studied using the CALPHAD technique in this paper. The modeling of Al2O3 in the liquid phase is modified from the traditional formula with the liquid phase represented by the ionic two-sublattice model as (Al3+, Sr2+) P ( $${\hbox{AlO}_{2}^{1-}}$$ , O2−) Q . Based on the measured phase equilibrium data and experimental thermodynamic properties, a set of thermodynamic functions has been optimized using an interactive computer-assisted analysis. The calculated results are compared with experimental data. A comparison between this system and similar systems is also given. [ABSTRACT FROM AUTHOR]

The Ag−Bi−Sn alloy system has been assessed twice, so far, for its potential applications as a lead-free solder material. The first assessment was based on binary data only; the second assessment introduced ternary parameters. It was noted in conclusion that more experimental studies were needed, especially for the liquid phase. The electromotive force (emf) measurement method was used in this study to determine the thermodynamic properties of liquid Ag−Bi−Sn alloys using solid electrolyte galvanic cells as shown below: Re, Ag−Bi−Sn, SnO2 |Yttria Stabilized Zirconia| Ni, NiO, Pt, Re, Sn, SnO2 |Yttria Stabilized Zirconia| Ni, NiO, Pt. Alloy compositions for in vestigation were chosen along three constant Bi-to-Sn ratio lines (1/3, 1, and 3) and with the silver content changing from 10 up to 90 at.%, every 10 at.%, resulting in a total of 27 different alloy samples. The temperature of the measurements varied from 975 to 1400 K. A linear dependence of the emf on temperature was observed for all compositions, and the appropriate line equations were derived. Excess partial Gibbs energies of Sn were then calculated at 1200 K and compared with the results of the calculations of both assessments; Gibbs energy of formation of SnO2 was determined as well. It was then shown that our new emf data fit better to the binary formalism-based calculations than to the second assessment results. [ABSTRACT FROM AUTHOR]

An emf method was employed to determine tin activities in the liquid Au-Cu-Sn alloys using solid electrolyte galvanic cells. The whole concentration range of the Gibbs triangle was covered, and emf readings were taken for both heating and cooling mode within temperature interval: 900-1360 K. Emf versus T relations were approximated by line equations, and its coefficients were listed in tables. Tin activity versus composition curves were constructed, displaying negative deviation from ideal behavior. Activity data were compared to the respective values calculated from COST 531 database using binary formalism, and relatively good agreement was observed. [ABSTRACT FROM AUTHOR]