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In order to lessen reliance on fossil fuels, a rise in interest in the utilization of fluctuating and intermittent heat sources derived from renewable energy (such as solar thermal, ocean thermal, and geothermal) and waste heat has been observed. These heat sources could be used to generate electricity at relatively low and medium temperatures, for example, through the organic Rankine cycle (ORC). In some case studies, various approaches have been developed to deal with and design ORCs in the desired operating condition utilizing suitable working fluids. This article aims to review some designs and integrated systems of ORC with thermal energy storage (TES) and a two-phase expansion system focusing on the utilization of medium- and low-temperature heat sources in which some subcritical ORCs are presented. Moreover, several possible control systems (both conventional and advanced ones) of ORC with TES and a two-phase expansion system are reported and compared. At the end of this article, the possible future developments of design and control systems are discussed to describe advanced ORC for utilizing low-grade heat sources. This study aims to provide researchers and engineers with an insight into the challenges involved in this process, making industrialization of ORC technology more extensive, in particular when combined with TES and a two-phase expansion system. [ABSTRACT FROM AUTHOR]

The quinary reciprocal system Li+,K+||F–,Cl–,Br–, has been divided into simplexes using graph theory: by making up an adjacency matrix and solving a logical expression. The results have been used to construct the phase tree of the system, which has a linear structure and consists of four stable secant tetrahedra, four stable pentatopes, and one stable hexatope. The number and composition of phases crystallizing in the system have been predicted. The LiF–KCl–KBr–Li2CrO4 stable tetrahedron has been studied using differential thermal analysis and X-ray diffraction. The tetrahedron has no invariant equilibrium points. The continuous series of solid solutions between potassium chloride and potassium bromide has been shown to be stable, without decomposition. Three solid phases have been shown to crystallize in the tetrahedron: LiF, Li2CrO4, and KClxBr1–x. [ABSTRACT FROM AUTHOR]

An experimental study of the phase equilibria of the Ho-rich part of the Ho-Ir-O ternary system at 1073 K by means of x-ray diffraction, differential scanning calorimetry, and scanning electron microscopy has been carried out. Ho-hcp and four binary compounds, namely Ho3Ir, Ho5Ir2, Ho5Ir3, and Ho2O3, were identified in the Ho-Ir-O model alloys after long-term annealing (350–1220 h). No solubility of iridium in Ho2O3 oxide and Ho-hcp was observed. No ternary phase was found. Based on the experimental results, an isothermal section of the Ho-rich part of the Ho-Ir-O system at 1073 K was constructed. In addition, the microstructure of as-cast alloys was studied. An irregular eutectic consisting of faceted Ho-phase in Ho3Ir phase was observed in the alloys with Ho-hcp + Ho3Ir + Ho2O3 phase composition, and the temperature of the eutectic reaction Ho-hcp + Ho3Ir ↔ liquid was determined. [ABSTRACT FROM AUTHOR]

Ruthenium addition inhibits the formation of the topologically close-packed phases in Ni-based superalloys and improves the solid solution strength of Ni–Ti shape memory alloys. Therefore, the Ni–Ti–Ru phase stability is a very valuable indicator of the effects of Ru in Ni-based superalloys and Ni–Ti shape memory alloys. In this study, the isothermal section at 1150 °C and liquidus surface projection of the Ni–Ti–Ru ternary system were determined experimentally using the equilibrated alloy method and diffusion couple method, respectively. Alloys were prepared through the arc-melting of Ni, Ti, and Ru (all 99.99% purity), and then vacuum encapsulation in quartz tubes, followed by annealing at 1150 °C for 36 to 1080 h depending on the alloy composition. Diffusion couples were fabricated by joining one single-phase block (τ1) with one two-phase block (Ni3Ti + γ(Ni)), and the couples were annealed under vacuum at 1150 °C for 168 h. Reaction temperatures of as-cast alloys were determined by differential scanning calorimetry performed with heating and cooling rates of 10 °C/min. Scanning electron microscopy and X-ray diffraction were used to analyze the microstructure. Seven three-phase regions were found at the 1150 °C isothermal section. Seven primary solidification regions and five ternary invariant reactions were deduced in the liquidus surface projection. A new ternary compound τ1 was discovered in both the isothermal section at 1150 °C and liquidus surface projection. The results aid in thermodynamic modeling of the system and provide guidance for designing Ni-based superalloys and Ni–Ti shape memory alloys. [ABSTRACT FROM AUTHOR]

It is of much interest to study the heavy hydrocarbon impact on the phase behavior of hydrocarbons. Using a method of the precision adiabatic calorimetry the phase equilibria in quaternary mixtures of methane, propane, octane, and nonane have been studied. The phase diagrams for investigated mixtures have been plotted based on the experimental data. The phase transitions were localized by the finite discontinuities in temperature derivatives of the thermodynamic potentials. The heat capacity, internal energy, pressure, and temperature derivative of pressure at constant volume were measured in the range 170–320 K, up to 40 MPa. Quaternary mixtures as quasi-binary mixtures are presented. The first quasi-component of the quasi-binary mixture is the binary mixture with the constant methane/propane ratio. The second quasi-component of the quasi-binary mixture is the binary mixture of octane and nonane. Investigated hydrocarbon system is the combination of the simple hydrocarbon mixtures for the low concentration of octane and nonane. In the earlier papers we presented the simple hydrocarbon mixtures for the low concentration of octane, nonane, and decane, and quaternary mixtures of methane, propane, octane, and decane for the low concentration of octane and decane, which are the combination of the simple hydrocarbon mixtures for the low concentration of octane and decane. Our investigations show that quaternary hydrocarbon mixture for the low concentration of octane and nonane as well as the simple hydrocarbon mixtures for the low concentration of octane, nonane, and decane split into three phases, the macrophase composed of methane, propane, octane, and nonane, and two microphases formed by octane and nonane. In this system octane and nonane dissolved in the macrophase partly. Besides, the heavy components provoke a split of the liquid part of the quaternary mixture into two liquid phases. [ABSTRACT FROM AUTHOR]

The isothermal section of the phase diagram of the Mg-Co-Ga ternary system at 200 °C for the full composition range was built. The formation of five ternary compounds was observed. The crystal structures of all ternary compounds: τ1—MgCo2Ga5 (own structure type, Pnnm space group), τ2—Mg3Co2Ga7 (C2/c space group, own structure type), τ3—MgCoGa2 (P21/n space group, own structure type), τ4—Mg1−xCo2−yGax+y (x = 0.06, y = 0.64) (Cmcm space group, own structure type), τ5—Mg1−xCo2−yGax+y (x = 0.10, y = 0.16) (R-3 m space group, own structure type) were investigated by means of single crystal diffraction. In addition to ternary compounds, solid solutions based on binary phases are formed in the system. The solid solution MgCo2−xGax (x = 0-1, P63/mmc space group, MgZn2 structure type) represent the largest area of homogeneity. The phase content of alloys was determined by SEM/EDX analysis. [ABSTRACT FROM AUTHOR]

Here, we present the results of DTA and XRD studies of phase equilibria in the 6Ag2Se + Ag8GeTe6 ↔ 6Ag2Te + Ag8GeSe6 reciprocal system (system A). A Т–х diagram of the Ag8GeSe6–Ag8GeTe6 boundary system, several inner polythermal sections, isothermal sections at 300 and 1000 K, and the liquidus surface projection were plotted. The Ag8GeSe6–Ag8GeTe6 system is a partially quasi-binary system; it features continuous substitutional solid solutions between Ag8GeTe6 and the high-temperature cubic Ag8GeSe6 phase (the δ phase). Once solid solutions are formed, the polymorphic transition temperature in Ag8GeSe6 decreases, thereby stabilizing the ion-conducting cubic phase in the range of ≥40 mol % Ag8GeTe6 compositions at room temperature and below it. System A is shown to be a reversible reciprocal system; its liquidus surface is comprised of three fields, which relate to the primary crystallization of the solid solutions between the high-temperature Ag2Se and Ag2Te (α phase) phases, IT-Ag2Te-base solid solutions (β phase), and the δ phase. The subsolidus portion of system A features complex interactions related to polymorphism in the terminal compounds and in phases based on them. [ABSTRACT FROM AUTHOR]

Magnesium and strontium play an important role in many industries, which are widely distributed in Oilfield brines in Nanyishan area of Qaidam Basin. In order to effectively separate magnesium and strontium mixed salts, the solid-liquid phase equilibria of the ternary system (NH4Cl–MgCl2–H2O) and quaternary system (NH4Cl–MgCl2–SrCl2–H2O) at 288.15 K have been determined by the methods of isothermal dissolution equilibrium. The phase diagram of the ternary system (NH4Cl–MgCl2–H2O) at 288.15 K contains two invariant points, three univariant curves, and three crystallization regions corresponding to NH4Cl, MgCl2·6H2O and double salt NH4Cl·MgCl2·6H2O. The phase diagram of the quaternary system (NH4Cl–MgCl2–SrCl2–H2O) has two invariant points, five invariant curves, four crystallization regions corresponding to NH4Cl, MgCl2·6H2O, SrCl2·6H2O, and double salt NH4Cl·MgCl2·6H2O. Due to the different dissolution behaviors of chloride salts in the aqueous systems, the component of MgCl2 has a relatively strong salting-out effect on other salts. [ABSTRACT FROM AUTHOR]

Special complex alloys of rare earth metals are recommended to perform deoxidation, microalloying, and modification in the production of low-carbon and high-quality steels. To reveal the mechanism of action of each alloy component, it is necessary to differentiate the action of each individual element. Yttrium is commonly referred to as rare earth metals, but its deoxidizing and modifying abilities have not been sufficiently studied. The use of yttrium is known to an increase the density, plasticity, scale resistance, and high-temperature corrosion resistance of steel and to substantially affect the shape, size, and distribution of nonmetallic inclusions. In this work, the interaction of yttrium, silicon, and carbon with oxygen dissolved in liquid iron is considered. The nonmetallic inclusions formed in this case can be determined on the FeO–Y2O3–SiO2 phase diagram. This diagram is not available in the literature; therefore, we modeled it using the available binary phase diagrams FeO–Y2O3, FeO–SiO2, and Y2O3–SiO2. Combined deoxidation with yttrium and silicon is possible only at yttrium concentrations of less than 0.0001% in liquid iron (oxide melt or yttrium silicates form as nonmetallic inclusions). If the yttrium concentration is higher than this value, yttrium is the only deoxidizer. In the presence of carbon, liquid nonmetallic inclusions can form in a very narrow liquid metal composition region, and the main nonmetallic oxide inclusion is yttrium oxide. At an yttrium concentrations below 0.0001% and a silicon concentration up to 1%, only carbon is a deoxidizer. Taking into account the Fe–Y–M–O–C (M = Ca, Mg, Al, Cr) systems studied earlier, we created a thermodynamic database was created for designing the compositions of complex yttrium-containing master alloys. [ABSTRACT FROM AUTHOR]

The deoxidizing ability of yttrium is insufficiently studied in spite of its high affinity to oxygen. In ferrous metallurgy, yttrium is often used in the form of an alloy with silicon. The effect of each of the components of a silica–yttrium alloy on liquid metal deoxidation can be established by studying the Fe–Y–Si–O system. In this case, the composition of the formed nonmetallic inclusions in steel is mainly determined by the type of Y2O3–SiO2 and FeO–Y2O3–SiO2 oxide phase diagrams conjugated with the region of metallic melts. In this work, the liquidus lines in the Y2O3–SiO2 oxide system are analyzed and calculated using thermodynamic modeling of phase equilibria in the phase diagrams of the oxide systems and the theory of subregular ionic solutions. A phase diagram of this system is constructed. According to thermodynamic analysis results, three compounds in the system are the most stable: yttrium oxyorthosilicate Y2O3⋅SiO2, yttrium orthosilicate 2Y2O3⋅3SiO2 (congruent melting, 1979 and 1915°C, respectively), and yttrium pyrosilicate Y2O3⋅2SiO2 (incongruent melting), which is consistent with the published data. The enthalpies and entropies of formation of these yttrium silicates from the components of the oxide melt, as well as the melting constants of these compounds, are calculated. The immiscibility field borders on the field of cristobalite at 1668°C in a concentration range of 0.593–0.980 (ionic fraction of SiO2) or 74.5–99 mol % SiO2. The determined enthalpy and entropy of yttrium silicates make it possible to start the next stage of the study: modeling of the phase diagram of the ternary FeO–Y2O3–SiO2 oxide system, which is necessary to consider the interaction of yttrium and silicon with oxygen in liquid iron. [ABSTRACT FROM AUTHOR]

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This work explores the use of thermodynamics‐informed Gaussian processes (GPs) and active learning (AL) to model activity coefficients and construct phase diagrams. Relying on synthetic data generated from an excess Gibbs energy model, GPs were found to accurately describe the activity coefficients of several binary mixtures across large composition and temperature ranges. Moreover, GPs could estimate their own uncertainty and identify composition/temperature regions where activity coefficient data provide the most information to the models. This was leveraged to build AL algorithms targeted at modeling phase equilibria. In many cases, a single active‐learning‐acquired data point was sufficient to describe the phase diagrams studied. Finally, the ability of AL to greatly reduce the amount of data needed to obtain accurate models was further verified on experimental case studies, namely individual ion activity coefficients, the solid–liquid and vapor–liquid equilibrium of deep eutectic solvents, and phase equilibria in ternary mixtures. [ABSTRACT FROM AUTHOR]

In this paper, the conditions of phase formation in the system CsOH–H2SO4–H3PO4–H2O are considered for the first time. The phase formation of Cs6(SO4)3(H3PO4)4 at t = 50 °C has been studied extensively. The main concentration boundary conditions for this compound are considered for the first time. The solubility congruence of Cs6(SO4)3(H3PO4)4 is shown. Conditions and approaches for obtaining crystals by isothermal evaporation and saturated solution temperature reduction methods are considered. The results of obtaining Cs6(SO4)3(H3PO4)4 crystals with maximum dimensions of ~20 mm are presented. [ABSTRACT FROM AUTHOR]

In this work, the mutual solubilities of sets of organic diluents (CHCl3, C6H6, C2H4Cl2, CCl4, C6H12, and n-hexane) with the organic compound ethylene glycol are investigated via gas chromatography (GC). The experimental data measured for these binary organic systems are used to adjust the future nonaqueous systems for the solvent extraction of various metals with ligands. The obtained results showed that the solubility of ethylene glycol decreased in the order CHCl3 > C6H6 > C2H4Cl2 > CCl4(0%) ≈ C6H12 ≈ n-hexane. On the other hand, the solubility of the tested traditional organic diluents in ethylene glycol decreased in the following order: C6H6 > CHCl3 > C2H4Cl2 > n-hexane > C6H12 > CCl4. 1H NMR was also used as an analytic method in order to compare the obtained results for the samples showing significant solubility only, including an additional study with 1,2- or 1,3-propanediol. The enhanced solubility of the C6H6 compound in ethylene glycol was identified here as critical due to the GC technique, which will be without future consequences in chemical technology. Therefore, it was found that the best molecular diluent for the recovery of metals among the tested ones is C6H12, with a green protocol as the new paradigm, replacing the aqueous phase with another nonaqueous phase, i.e., a second organic diluent. [ABSTRACT FROM AUTHOR]

Phase equilibria in the Ag2Se–Ag8SiSe6–Ag8GeSe6 system were studied by differential thermal analysis and X-ray diffraction thechnique. Based on the experimental results and literature data, the projection of the liquidus surface of the Ag2Se–Ag8SiSe6–Ag8GeSe6 system, the isothermal section at 300 K and some polythermal sections of the phase diagram were constructed. It was determined that continuous series of solid solution are formed based on high-temperature cubic modification and limited solid solution areas are formed based on low-temperature modification of initial compounds on the Ag8SiSe6–Ag8GeSe6 side of concentration triangle. The formation of solid solutions leads to a sharp decreasing of polymorphic transition temperatures of ternary compounds and stabilization of high-temperature phases at room temperature. The liquidus surface of the Ag2Se–Ag8SiSe6–Ag8GeSe6 system consists of 2 areas reflecting the initial crystallization of α'-phase based on HT-Ag2Se and HT-Ag8Si1-xGexSe6 solid solutions. The obtained new phases are of interest as environmentally safe materials with thermoelectric properties and mixed ionelectron conductivity. [ABSTRACT FROM AUTHOR]

In this study, we investigate the phase behaviour of associating fluids with two interacting sites inside a functionalised cylindrical pore using Grand Canonical Monte Carlo simulations. The structural behaviour of the coexisting liquid and vapor phases is characterised by the radial density, orientation, and bond formation inside cylindrical pores of different radii. The critical properties of the phase diagrams of the confined fluids were investigated as functions of the associating strengths at different pore sizes. The impact of site strength on the phase diagram is characterised by the critical and structural properties of the coexisting phases inside the cylindrical pore. The organisation of the associating fluids near the pore surface strongly depends on the surface – site interaction with the interfacial fluid molecules that propagate to the bulk regime of the system. Thus, the surface site density is a crucial parameter for manipulating the properties of coexisting phases and critical properties of the phase diagram. [ABSTRACT FROM AUTHOR]

In this work we evaluate the technical feasibility of using liquefied CO 2 + propane as a solvent for the purification of lubricant oils. A model lubricant made of a silicone oil (polydimethylsiloxane, MW ≈6000) and Decamethylcyclopentasiloxane (D5, MW: ≈371) is prepared to study the extraction process. The phase behavior of the CO 2 +propane+silicone oil system is evaluated in a high-pressure view cell to set the window of operating conditions where the system exhibits partial liquid miscibility (298–323 K). Then, we add D5 monomer (2 mass % in the silicone oil) to the previous ternary mixture, and we assess the effect of solvent composition (CO 2 /propane: 60/40–90/10) over the fractionation process by means of new equilibrium measurements. The solvent-free distribution coefficient of D5 between the liquid phases is determined from experimental determinations. Results evidence that liquefied gases with propane concentrations between 10 and 26 mass % are suitable to remove the monomers from the raw lubricant oils with good selectivity and extraction yields. Conceptual engineering designs of the liquid-liquid fractionation process are performed to determine the suitable solvent composition that completely removes the monomer present in the lubricant oil and to assess the recovery of the lubricant oil. [Display omitted] • Synthetic lubricant purification assessment through liquefied CO2 +propane mixtures. • High CO 2 concentrations in the solvent favors the liquid partial miscibility with the lubricant. • Liquid-liquid-vapor phase equilibrium and phase composition measurements. • Fractionation of Polydimethylsiloxane and Decamethylcyclopentasiloxane model lubricant. • Conceptual engineering design of the liquid-liquid fractionation process using liquefied gases. [ABSTRACT FROM AUTHOR]

The phase assemblage of the Li+,Na+,K+||F–,Cl–,Br– five-component reciprocal system was studied for the first time. The phase tree obtained by partition of the phase assemblage into stable elements is linear. It consists of the following stable elements: the LiF–NaF–KF–KBr–KCl pentatope, LiF–NaBr–NaCl–KCl–KBr–NaF hexatope, and NaCl–KCl–KBr–LiBr–LiCl–LiF–NaBr heptatope, linked by the LiF–NaF–KCl–KBr stable tetrahedron and the LiF–KBr–NaBr–NaCl–KCl square pyramid (pentatope). Phase equilibria in the LiF–KCl–KBr–NaBr–NaCl stable pentatope were studied by differential thermal analysis (DTA). Monovariant phase equilibrium L ⇄ LiF + NaClxBr1– x + KClyBr1 –y occurs in the pentatope, where NaClxBr1 –x and KClyBr1 –y are continuous solid solutions (css) between NaCl and NaBr, KCl and KBr salt pairs, respectively. The composition of the mixture at point Min◻ 591 and the lowest monovariant equilibrium temperature were determined. A 3D computer model was designed as a projection of the phase assemblage on the LiF–KCl–KBr–NaBr–NaCl pentatope in KOMPAS-3D software. The volumes of crystallizing equilibrium phases were outlined. [ABSTRACT FROM AUTHOR]

The Dy–Al–Si ternary system has been experimentally studied, as the effect of the dysprosium addition on the constitution and topology of the liquidus surface, focusing on the (Al) rich part. The system has been investigated in a composition range of up to about 58 at% silicon. The alloys constitution and the liquidus surface projection have been determined by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS), X-ray powder diffraction (XRPD), and differential thermal analysis (DTA). This work is part of a research framework on the properties and solid–liquid phase equilibria of the R Al–Si (R: rare earth) systems. These data, along with the ternary systems isothermal section, are needed to outline the design, plan, and development of new Al–Si-based alloys. In the Dy–Al–Si system, four primary crystallization fields have been experimentally detected: (Si), DyAlxSi(2−x) (orthorhombic form), Dy2Al3Si2 (Τ2), and DyAl(3−x)Six. The following three invariant equilibria have been identified: at 566 °C the ternary eutectic L ⇆ DyAl2Si2 + (Al) + (Si), at 630 °C the U1 L+ DyAl3 ⇆ Dy2Al3Si2 + (Al), and at 562 °C the U2: L+ Dy2Al3Si2 ⇆ DyAl2Si2 +(Al) reactions. A comparison with other known R Al–Si systems has been conducted. [ABSTRACT FROM AUTHOR]

Vapor pressures and other thermodynamic properties of liquids, such as density and enthalpy of mixtures, are the key parameters in chemical engineering for designing new process units, and are also essential for understanding the physical chemistry, macroscopic and molecular behavior of fluid systems. In this work, vapor pressures between 278.15 and 323.15 K, densities and enthalpies of mixtures between 288.15 and 318.15 K for the binary mixture (2-propanol + 1,8-cineole) have been measured. From the vapor pressure data, activity coefficients and excess Gibbs energies were calculated via the Barker's method and the Wilson equation. Excess molar volumes and excess molar enthalpies were also obtained from the density and calorimetric measurements. Thermodynamic consistency test between excess molar Gibbs energies and excess molar enthalpies has been carried out using the Gibbs–Helmholtz equation. Robinson–Mathias, and Peng–Robinson–Stryjek–Vera together with volume translation of Peneloux equations of state (EoS) are considered, as well as the statistical associating fluid theory that offers a molecular vision quite suitable for systems having highly non-spherical or associated molecules. Of these three models, the first two fit the experimental vapor pressure results quite adequately; in contrast, only the last one approaches the volumetric behavior of the system. A brief comparison of the thermodynamic excess molar functions for binary mixtures of short-chain alcohol + 1,8-cineole (cyclic ether), or +di-n-propylether (lineal ether) is also included. [ABSTRACT FROM AUTHOR]

CaO–Al 2 O 3 -CeO x slag system is of great significance for designing a new type of metallurgical slag system suitable for rare earth steel. In this paper, the phase equilibria of CaO–Al 2 O 3 -CeO x system were experimentally studied. Isothermal sections of CaO–Al 2 O 3 –Ce 2 O 3 system and CaO–Al 2 O 3 –CeO 2 system at 1600 °C were constructed, respectively. 4 three-phase fields, 5 two-phase fields and a single liquid phase field in CaO–Al 2 O 3 –Ce 2 O 3 system were determined; 2 three-phase fields, 3 two-phase fields and a single liquid phase field in CaO–Al 2 O 3 –CeO 2 system were determined. On this basis, the dissolution process of three typical inclusions (viz. Al 2 O 3 , CeAl 11 O 18 and CeAlO 3) in CaO–Al 2 O 3 –Ce 2 O 3 slag system was discussed. [ABSTRACT FROM AUTHOR]

The equilibrium-phase relations between copper mattes and spinel-saturated iron silicate slags were investigated at 1250°C and pSO2 of 0.25 atm. The experiments were conducted in synthesized spinel crucibles (Fe3O4) in controlled CO-CO2-SO2-Ar gas mixtures using a high-temperature isothermal equilibration/quenching technique. The equilibrium-phase compositions were characterized using an electron probe X-ray microanalyzer. The compositions of matte and slag were displayed as a function of matte grade or oxygen partial pressure. The present results obtained at spinel saturation in the matte-slag equilibrium system were compared with observations in the literature. This study improves the experimental thermodynamic data on the matte-slag-spinel-gas equilibria systems. [ABSTRACT FROM AUTHOR]

Printed circuit boards (PCBs) from antiquated electronic goods were processed by a pyrometallurgical route to produce and separate alloy and slag phases. The process involved initial size reduction of PCBs, followed by pyrolysis at 500 °C for 6 h and finally smelting of the solid materials in an electric furnace. A preliminary smelting test was performed at 1600 °C to estimate the composition of the slag generated. In later kilogram-scale smelting experiments, B2O3 flux was added along with CaO and SiO2 to decrease the liquidus temperature required to smelt the PCBs. The level of fluxing was adapted from earlier phase equilibria studies of the CaO-Al2O3-SiO2-B2O3 slag system. Results showed that the flux decreased the melting temperature and assisted the recovery of most valuable metals within the alloy phase at 1350 °C smelting temperature. The alloy phase recovered 99.8% of Cu, 99% of Sn, and 100% of precious metals (Au, Ag, Pt). A fluxing strategy for smelting high Al2O3 containing e-waste PCBs was proposed based on the experimental findings of this research. [ABSTRACT FROM AUTHOR]

Garnet's stability in arc magmas and its influences on their differentiation were explored experimentally in a typical basalt, andesite, and dacite at conditions of 0.9–1.67 GPa, 800–1300 °C, with 2–9 wt.% added H2O, and with oxygen fugacity buffered near Re + O2 = ReO2 (~ Ni-NiO + 1.7 log10 bars). Garnet did not grow at 0.9 GPa in any of the compositions, even with garnet seeds added to facilitate nucleation. At 1.0–1.2 GPa, garnet grew as thin rims (< 5 µm) on introduced garnet seeds coexisting with dacitic to rhyodacitic liquids at temperatures ≤ 1000 °C. At 1.3 GPa, garnet grew readily with no seeds from 900 to 1100 °C coexisting with liquids ranging from peraluminous basaltic andesite to rhyodacite, and at 1.46 GPa, garnet was stable as hot as 1150 °C in metaluminous basaltic liquid. Garnet grew as a liquidus phase only in the dacite, a composition similar to the average upper continental crust. Inverse experiments on the dacite determined a liquidus multiple-saturation point with garnet, plagioclase, orthopyroxene, calcic clinopyroxene, and amphibole at 975 °C, 1.46 GPa, with 7 wt.% dissolved H2O. Such dacitic and more evolved melts can be products of peritectic reactions that with decreasing temperature consume garnet, calcic clinopyroxene, and melt components, producing amphibole and less abundant but more evolved melts. For this reason, experiments on product melts need not produce reactant minerals, accounting for some disparities in published experimental results on the apparent stability of garnet in intermediate-to-evolved arc magmas. Results on more mafic compositions are more reliable guides and show that liquids of arc dacitic composition, and more evolved compositions, would coexist stably with garnet only in the deepest portions of continental-margin arc crust with average thickness and density (~ 43 km, ~ 1.2 GPa) or in the underlying shallow mantle. Metaluminous arc basaltic, basaltic andesitic, and many andesitic liquids would not coexist stably with garnet at pressures ranging from the crust to at least the midpoint of the mantle wedge, but results in the literature allow that some andesitic liquids with higher Fe/Mg than common in arcs may also saturate with garnet in the deeper portions of average-thickness continental arc crust. A persistent issue, however, is that, at pressures of the lower continental crust or shallow mantle (0.7–1.67 GPa), arc basalts may crystallize or differentiate within a regime that includes a clinopyroxene-dominated high-T interval (1250–1150 °C) with lesser orthopyroxene. This crystallizing assemblage drives coexisting liquids to become peraluminous at 53–60 wt.% SiO2 (normalized anhydrous), whereas arc igneous suites mainly attain peraluminous compositions at 65–70 wt.% SiO2. Thus, simple, progressive crystallization-differentiation of appropriately hydrous, oxidized basalts near the base of continental arc crust does not generate, or does not act alone to produce, the dominantly metaluminous arc andesites. Scarcity of natural peraluminous andesites and basaltic andesites, and of correlative intrusions, despite their demonstrated production by deep basalt differentiation, may result from mixing accompanying crystallization-differentiation. Cumulates produced by arc basalts at deep crustal and upper mantle pressures have densities equal to or exceeding those of upper mantle peridotite until coexisting liquid compositions reach or exceed that of silicic andesite or dacite, after which cumulates become buoyant relative to the mantle. Deep differentiation may therefore be efficient until that point, with cumulates being lost to the mantle and melts evolving rapidly to silicic andesite through dacite compositions. This process results in both an intermediate overall composition for the buoyant crust, and deep-crustal dacitic through rhyolitic melts that can mix with deep basalts thereby producing metaluminous basaltic andesites and andesites. [ABSTRACT FROM AUTHOR]

This study presents a new possibility to deposit the polycrystalline Cu2ZnSnS4 (CZTS) thin film at low temperature using an improved close‐distance chemical vapor deposition reactor. Firstly, a theoretical study is conducted to predict the iodine pressure (PI2) and the substrate temperature (Ts) as the optimal conditions for the deposition of CZTS. The theoretical model is based on the minimization of the Gibbs energy of the Cu‐Zn‐Sn‐S‐I chemical system. An experimental study is realized, and the predicted optimal conditions to obtain quasi‐stoichiometric depositions are tested. The X‐ray diffraction, Raman spectroscopy, energy dispersive spectroscopy, scanning electron microscopy, and UV–vis–NIR spectroscopy are used to analyze the thin films elaborated at substrate temperatures of Ts = 400 and 550 °C for iodine pressure PI2 = 0.03 × 105 Pa. With the help of the thermodynamical calculations, the results show that it is possible to grow a good quality CZTS thin film at a low substrate temperature of 400 °C. [ABSTRACT FROM AUTHOR]

Precise data on the non-variant equilibrium of the four phases (vapor–aqueous solution–ice–gas hydrate) in P–T coordinates are highly desired for developing accurate thermodynamic models and can be used as reference points (similar to the triple point of water). Using the two-component hydrate-forming system CO2–H2O, we have proposed and validated a new express procedure for determining the temperature and pressure of the lower quadruple point Q1. The essence of the method is the direct measurement of these parameters after the successive formation of the gas hydrate and ice phases in the initial two-phase gas–water solution system under intense agitation of the fluids. After relaxation, the system occurs in the same equilibrium state (T = 271.60 K, P = 1.044 MPa), regardless of the initial parameters and the order of crystallization of the CO2 hydrate and ice phases. Considering the combined standard uncertainties (±0.023 K, ±0.021 MPa), the determined P and T values agree with the results of other authors obtained by a more sophisticated indirect method. Validating the developed approach for systems with other hydrate-forming gases is of great interest. [ABSTRACT FROM AUTHOR]

The impact of oxygen impurity on phase relationships in the Zr-Mo-Fe system (Zr > 30 at.%) at 1000 °C was investigated by means of x-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy analysis. An oxygen-stabilized ternary compound γ-Zr2(Mo,Fe), derived from Ti2Ni type Zr4Fe2O, with cell parameter of a = 1.2213 nm was observed to be present in the investigated Zr-Mo-Fe alloys. The phase relationships of the Zr-Mo-Fe (O) system at 1000 °C in the Zr-rich corner consist of 3 four-phase regions, i.e., [βZr + λ-Zr(Mo,Fe)2 + γ-Zr2(Mo,Fe) + ZrMo2], [βZr + λ-Zr(Mo,Fe)2 + γ-Zr2(Mo,Fe) + Liquid], and [λ-Zr(Mo,Fe)2 + γ-Zr2(Mo,Fe) + Liquid + ZrFe2]. The previously detected Zr9Mo4Fe compound was not observed in this work. [ABSTRACT FROM AUTHOR]

Sb2Te3 is an important thermoelectric material. Co is a potential diffusion barrier. This study examined the electroplated Co/Sb2Te3 interfacial reactions at 300 °C, 400 °C and 500 °C. To provide fundamental information and for better understanding the reaction paths, the Co-Sb-Te phase equilibria isothermal sections at these three temperatures are proposed. No ternary compound is found. The 400 °C isothermal section contains (Co), (Sb), (Te), β-CoSb, β-Co1−xTe, CoSb3, δ-(Sb2Te), γ-(SbTe), Sb2Te3 and a continuous solid solution γ-Co(Sb,Te)2. At 500 °C, except for Te being molten, the phase relationships are similar to those at 400 °C. At 300 °C, although γ-CoSb2 and γ-CoTe2 have very significant mutual solubilities, they are two separate phases and do not form a continuous solid solution. In the Co/Sb2Te3 couple reacted at 300 °C, only one reaction phase, γ-CoTe2 with Sb solubility, is formed. Similar results are found in the Co/Sb2Te3 couple reacted 400 °C, and the reaction phase is the continuous solid solution γ-Co(Sb,Te)2. Two reaction phases, β-Co1-xTe and γ-Co(Sb,Te)2, are found in the couple reacted at 500 °C. The compositional ratio of Sb/Te in the reaction phase remained at 2/3 indicates that Co is the dominating diffusion species. The reaction phases are formed rapidly by Co penetration into the Sb2Te3 substrate. A peculiar phenomenon was found with the reaction layer that formed on the side of Co that was not in direct contact with the Sb2Te3 substrate which will be further investigated. [ABSTRACT FROM AUTHOR]

Sb2Te3 is an important thermoelectric material. The interfacial reactions in the Ni/Sb2Te3 and Co0.2Ni0.8/Sb2Te3 couples are examined to verify if Ni and Co0.2Ni0.8 are suitable barrier layer materials. The Ni-Sb-Te phase equilibria isothermal sections and Co-Ni-Sb-Te isothermal tetrahedrons are proposed to provide fundamental information and for better understanding of the interfacial reactions. Only one reaction phase, λ2-NiSb1−xTe2x, is observed in the Ni/Sb2Te3 couples reacted at 200°C, 300°C, and 400°C. When reacting at 500°C for 6 h, the reaction phase is λ1-Ni(Sb1−xTex)1+y. With a longer reaction time, the second phase, Ni5.66SbTe2, is formed. Note, the compositional ratios of Sb/Te of all the reaction phases remain as 2/3. The result indicates that Ni is the dominating diffusion species. The reaction results in the Co0.2Ni0.8/Sb2Te3 couples are similar to those in the Ni/Sb2Te3 couples. The reaction phase at 400°C is λ2-NiSb1−xTe2x , and are λ1-Ni(Sb1−xTex)1+y + Ni5.66SbTe2 phases at 500°C with a longer reaction time. The compositional ratios of Sb/Te in the reaction phases are also 2/3, and the Co contents in the reaction phases are very limited. Ni is also the dominating diffusion species in the Co0.2Ni0.8/Sb2Te3 couples. [ABSTRACT FROM AUTHOR]

Vapor–liquid equilibrium (VLE) and density data for binary systems of branched alkanes + ethyl acetate are scarce in the literature. In this study, the binary mixtures 3-methylpentane + ethyl acetate and 2,3-dimethylbutane + ethyl acetate were investigated. Density measurements at atmospheric pressure were performed using a vibrating tube density meter at 293.15, 298.15 and 303.15 K. Large and positive excess molar volumes were calculated and correlated using a Redlich–Kister-type equation. Isobaric VLE data at 101.3 kPa were obtained using a Gillespie-type recirculation ebulliometer. Equilibrium compositions were determined indirectly from density measurements. The experimental data were checked for consistency by means of the Fredenslund test and the Wisniak (L-W) test and were then successfully correlated using the NRTL model. The newly studied binary systems display high deviations from ideality and minimum boiling azeotropes, the coordinates of which are reported in this work. [ABSTRACT FROM AUTHOR]

The phase equilibria in the ZrO2–HfO2–Nd2O3 ternary system at 1500 °C and 1700 °C were studied over the whole concentration range by X-ray diffraction and microstructural analyses. Corresponding isothermal sections were constructed from the data obtained. It was found that solid solutions in this system are derived from a tetragonal (T) modification of ZrO2, a monoclinic (M) modification of HfO2, a hexagonal (A) modification of Nd2O3, a cubic phase with a fluorite (F) structure of ZrO2 (HfO2), and an ordered phase with a pyrochlore (Py) structure of Nd2Zr2O7 (Nd2Hf2O7). The phase boundaries and unit cell lattice parameters were determined. The solubility of Nd2O3 in M − HfO2 is pretty low and about less than 1 mol%, as confirmed by XRD and microstructural analyses. The ordered pyrochlore-type (Py) phase of Nd2Zr2O7 (Nd2Hf2O7) forms continuous series of solid solutions at 1500 °C and 1700 °C. The homogeneous region of these continuous series of solid solutions changes insignificantly with increasing temperature. The changes in the construction of the isothermal section of the ZrO2-HfO2-Nd2O3 phase diagram at 1500 °C compared to 1700 °C are associated with the thermal stability of cubic fluorite-type (F) solid solutions. Other phases in the ZrO2-HfO2-Nd2O3 ternary system are not detected at the studied temperatures.

Ti-Cr-V-based alloys have been utilized across various domains, including aerospace structural and functional materials and hydrogen storage materials. Investigating the phase relations in the Ti-Cr-V system is significant in supporting the material design for these applications. In the present work, the isothermal sections at 1000, 1100, and 1200 °C for the Ti-Cr-V system were precisely determined through a systematic investigation using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The phase region of Cr2Ti was entirely elucidated for the first time. As the temperature decreased from 1200 to 1000 °C, the V solubility range of Cr2Ti increased from 5.3 wt.% to 10.0 wt.%, while the Ti solubility range essentially remained constant at approximately 31.0–33.9 wt.%. In addition, it was suggested that the stable structure of Cr2Ti was C36 at 1200 °C and C15 at 1000 and 1100 °C. The present work will support thermodynamic re-assessment research.

Phase equilibria in Ca(NO3)2–C2H5OH–H2O system sections and anti-icing properties of calcium nitrate–ethanol compositions with a component ratio from 1 : 3 to 3 : 1 are studied. The temperatures and composition of eutectics with ice and the melting ability of nitrate–ethanol compositions at temperatures of –5 and –10°C are determined. The compositions characterized by good anti-icing properties are revealed. [ABSTRACT FROM AUTHOR]

Abstract—Phase equilibria in Ca(NO3)2–C3H6(OH)2–H2O system sections and anti-icing properties of calcium nitrate–propylene glycol compositions with a component ratio from 1 : 3 to 3 : 1 are studied, and the temperatures and composition of eutectics with ice and the melting capacity of nitrate–propylene glycol compositions at temperatures of –5 and –10°C are determined. The compositions characterized by good anti-icing properties are identified. [ABSTRACT FROM AUTHOR]

While rhenium has proven to be an ideal material in fast-cycling high-temperature applications such as rocket nozzles, its prohibitive cost limits its continued use and motivates a search for viable cost-effective substitutes. We show that a simple design principle that trades off average valence electron count and cost considerations proves helpful in identifying a promising pool of candidate substitute alloys: The Mo-Ru-Ta-W quaternary system. We demonstrate how this picture can be combined with a computational thermodynamic model of phase stability, based on high-throughput ab initio calculations, to further narrow down the search and deliver alloys that maintain rhenium's desirable hcp crystal structure. This thermodynamic model is validated with comparisons to known binary phase diagram sections and corroborated by experimental synthesis and structural characterization demonstrating multiprinciple-element hcp solid-solution samples selected from a promising composition range.

The phase equilibrium diagram of the Tm–Cr–Ge ternary system was constructed at a temperature 1070 K based on the results of X-ray phase, microstructural analyzes and energy-dispersive X-ray spectroscopy in the whole concentration range. At the temperature of investigation, two new ternary compounds are realized in the system: TmCr6Ge6 (SmMn6Sn6 structure type, space group P6/mmm, a=0.51506(1), c=0.82645(2) nm) and Tm4Cr4Ge7 (Zr4Co4Ge7 structure type, space group I4/mmm, а=1.39005(9), с=0.54441(1) nm). Inclusion of Cr atoms in the structure of the binary germanide TmGe2 (structure type ZrSi2) up to 10 at. % Cr leads to the formation of a solid solution TmCrxGe2 (x = 0-0.33).

An “energy evolution” is necessary to manifest an environmentally sustainable world while meeting global energy requirements, with natural gas being the most suitable transition fuel. Covering the ever-increasing demand requires exploiting lower value sour gas accumulations, which involves an acid gas treatment issue due to the greenhouse gas nature and toxicity of its constituents. Successful design of the process requires avoiding the formation of acid gas vapor which, in turn, requires time-consuming and complex phase behavior calculations to be repeated over the whole operating range. In this work, we propose classification models from the Machine Learning field, able to rapidly identify the problematic vapor/liquid encounters, as a tool to accelerate phase behavior calculations. To set up this model, a big number of acid gas instances are generated by perturbing pressure, temperature, and acid gas composition and offline solving the stability problem. The generated data are introduced to various classification models, selected based on their ability to provide rapid answers when trained. Results show that by integrating the resulting trained model into the gas reinjection process simulator, the simulation process is substantially accelerated, indicating that the proposed methodology can be readily utilized in all kinds of acid gas flow simulations.

The equilibrium phase space of the Ag–In–Se system in the part AgInSe2–InSe–Se below 500 K consists seven three-phase regions In2Se3–AgIn11Se17–Se (I), AgIn11Se17–AgIn5Se8–Se (II), AgIn5Se8–AgInSe2–Se (IІІ), In2Se3–In6Se7–AgIn11Se17 (ІV), In6Se7–AgIn11Se17–AgIn5Se8 (V), InSe–In6Se7–AgIn5Se8, and InSe–AgIn5Se8–AgInSe2 (VI). Division of the AgInSe2–InSe–Se into separate phase regions was performed based on electromotive force vs temperature dependences of six electrochemical cells (ECCs) of the type: (−) С | Ag | SЕ | R(Ag+) | PЕ | С (+), where C is the graphite (inert electrode), Ag is the left (negative) electrode, SE is the solid-state electrolyte (Ag3GeS3Br glass), PE is the right (positive) electrode, R(Ag+) is the buffer region of PE that contacts with SE. The process of forming of the thermodynamically stable set of phases from phase non-equilibrium mixture of compounds specified in (I)–(VI) is carried out in the R(Ag+) region. The Ag+ ions act as the small nucleation centers for stable phases. Based on the temperature dependences of the electromotive force of ECCs with PE of the (I)–(VI) phase regions, the standard thermodynamic functions of the binary In6Se7 and three ternary compounds in the adjacent phase regions were calculated for the first time. The agreement of the calculated values of the standard Gibbs energies of the AgIn5Se8 compound in two different phase regions (II) and (V): -(819,6±8,9) kJ·mol −1 and -(820,0±8,9) kJ·mol −1 characterizes the phase composition of the regions (I), (II), (IV), and (V) below 500 K as a combination of compounds of formulaic composition.

The equilibrium conditions of sII methane/propane hydrates have been experimentally determined for the C3H8/CH4-H2O-urea system. The equilibrium dissociation temperatures and pressures of sII hydrates span a wide P,T-range (266.7–293.9 K; 0.87–9.49 MPa) and were measured by varying the feed mass fraction of urea in solution from 0 to 50 mass%. The experimental points at feed urea concentration ≤ 40 mass% correspond to the V-Lw-H equilibrium (gas-aqueous urea solution-gas hydrate). A four-phase V-Lw-H-Su equilibrium (with an additional phase of solid urea) was observed because the solubility limit of urea in water was reached for all points at a feed mass fraction of 50 mass% and for one point at 40 mass% (266.93 K). Gas hydrate equilibria were measured using a high-pressure rig GHA350 under isochoric conditions with rapid fluid stirring and slow ramp heating of 0.1 K/h. Each measured point represents complete dissociation of the sII hydrate. The phase equilibrium data was compared with the literature reported for the C3H8/CH4-H2O and CH4-H2O-urea systems. A comprehensive analysis of the thermodynamic inhibition effect of urea to sII C3H8/CH4 hydrates on pressure and concentration of the inhibitor was carried out. The phase composition of the samples was analyzed by powder X-ray diffractometry at 173 K.

Knowledge of the liquidus is important for the design and processing of many materials. For instance, deep eutectics are important for the design of metallic glasses, and recently multi-principal element alloys have been designed based on eutectic compositions or melting temperatures extrapolated from binary liquidus data. In this study, we provide a general framework for predicting binary liquidus only from the properties of the pure elements and thermodynamic properties calculated by Miedema’s model. Our framework combines three machine learning models that are trained and evaluated on liquidus data collected from 466 CALPHAD assessments of binary phase diagrams. The first model predicts the formation of liquid miscibility gaps with a prediction accuracy of 95.3%, outperforming the empirical Mott model. The second and third models predict the equilibrium onset temperature of solidification and the critical temperature of liquid miscibility gaps, respectively. An important feature of our models is that they can give indications of the presence of congruent melting phases and eutectics. Using our framework, we predict the liquidus in 1563 binary systems not included in our CALPHAD dataset, many of which are unknown. By collecting more data, our framework will continue to grow towards better liquidus prediction.

To determine the ability of dimethyl sulfoxide (DMSO) to inhibit methane hydrate formation by the thermodynamic mechanism, we measured the pressures and temperatures of monovariant equilibrium of three phases: gaseous methane, aqueous DMSO solution, and methane hydrate. A total of 54 equilibrium points were obtained. Hydrate equilibrium conditions have been measured for eight different concentrations of dimethyl sulfoxide ranging from 0 to 55 mass%, at temperatures of 242–289 K and pressures of 3–13 MPa. Measurements were performed in an isochoric autoclave (volume of 600 cm3, inside diameter of 8.5 cm) at a heating rate of 0.1 K/h and intense fluid agitation (600 rpm) with four-blade impeller (diameter of 6.1 cm, blade height of 2 cm). The specified stirring speed for aqueous DMSO solutions at 273–293 K is equivalent to a range of Reynolds numbers of 5.3‧103–3.7‧104. The endpoint of methane hydrate dissociation at defined temperature and pressure values was taken as the equilibrium point. The anti-hydrate activity of DMSO was analyzed on a mass% and mol% scale. Precise correlations between the thermodynamic inhibition effect of dimethyl sulfoxide ΔTh and the influencing factors (DMSO concentration and pressure) were derived. Powder X-ray diffractometry was employed to examine the phase composition of the samples at 153 K. Measurement of ice freezing points in aqueous solutions of dimethyl sulfoxide (up to 50 mass%) at ambient pressure allowed us to clarify the location of the liquidus line in the DMSO-H2O system and to check the hydrate equilibrium data for thermodynamic consistency.

Phase equilibria in the Ag2S–Ag8SiS6–Ag8GeS6 system were studied using differential thermal analysis and powder X-ray diffraction technique. Boundary section Ag8SiS6 – Ag8GeS6, liquidus surface projection, an isothermal section of the phase diagram at 300 K, and some polythermal sections of the studied system were constructed. The formation of continuous series of solid solutions between both crystalline modifications of the starting compounds was determined in the Ag8SiS6–Ag8GeS6 system. The liquidus surface of the Ag2S–Ag8SiS6–Ag8GeS6 system consists of two fields corresponding to the primary crystallization of the high-temperature modifications of the HT-Ag8Si1-xGexS6 and HTAg 2S phases. Lattice parameters for both modification of solid solutions were calculated based on powder X-ray diffraction data. The concentration dependence of lattice parameters obeys Vegard’s rule. The obtained new phases are of interest as environmentally safe materials with thermoelectric properties and mixed ionelectron conductivity

New bromide compounds A2BIBIIIBr6 with a double perovskite structure provide variety and flexibility of optoelectronic properties, and some of them are of poor toxicity in comparison with such popular lead halides. The promising compound with a double perovskite structure was proposed recently for the ternary system of CsBr-CuBr-InBr3. Analysis of phase equilibria in the CsBr-CuBr-InBr3 ternary system showed stability of the quasi-binary section of CsCu2Br3–Cs3In2Br9. Formation of the estimated phase Cs2CuInBr6 by melt crystallization or solid-state sintering was not observed, most likely, as a result of higher thermodynamic stability of binary bromides CsCu2Br3 and Cs3In2Br9. The existence of three quasi-binary sections was observed, while no ternary bromide compounds were found. [ABSTRACT FROM AUTHOR]

Phase equilibria and structural transformations in the La2O3–Y2O3–Gd2O3 system at 1600°C were studied by X-ray diffraction, electron microscopy, and petrography in the entire composition range. Fields of solid solutions based on hexagonal (A) modification of La2O3, cubic (C) modification of Y2O3, and monoclinic (B) modification of La2O3 (Gd2O3) were identified in the system. The starting materials were La2O3, Gd2O3, and Y2O3 (99.99%) powders. Samples were prepared with concentration steps of 1–5 mol.%. Weighed portions of the oxides were dissolved in HNO3 (1 : 1) solutions. This was followed by evaporation of the solutions and decomposition of the nitrates at 800°C for 2 h. The samples were heat-treated in three stages: 1100°C (168 h), 1500°C (70 h), and 1600°C (10 h) in air in furnaces with FeCrAl (H23U5T) and molybdenum disilicide (MoSi2) heating elements. X-ray diffraction analysis was carried out using the powder method with a DRON-3 diffractometer at room temperature (Cu-Kα radiation). The scanning step was 0.05–0.1° at angles 2θ = 15–90°. The isothermal section of the La2O3–Y2O3–Gd2O3 phase diagrams at 1600°C was characterized by three single-phase (A-La2O3, B-La2O3 (Gd2O3), C-Y2O3) and two two-phase (A + B, B + C) regions. The solubility limits were determined, and composition dependences of the lattice parameters for the phases formed in the system were plotted. No ordered perovskite-type phase was found in the system at 1600°C. A continuous series of solid solutions based on the monoclinic modification of B-La2O3(Gd2O3) formed in the system and occupied the largest area of the isothermal section. Yttrium oxide stabilized the total mutual solubility of lanthanum and gadolinium oxides. With the addition of heavier ions, the lattice parameters of the B modification reduced and the lattice volume and, accordingly, density increased. The lattice of solid solutions based on the B modification of rare-earth metal oxides became more densely packed with a higher concentration of yttrium oxide. [ABSTRACT FROM AUTHOR]

We have investigated phase relations along a number of joins in the subsolidus region of the Cs2MoO4–BaMoO4–Gd2(MoO4)3 system using X-ray diffraction and differential thermal analysis and constructed its phase compatibility diagram. A ternary molybdate with the composition CsBaGd(MoO4)3 and a monoclinic scheelite-like structure (sp. gr. P21/n) has been synthesized. Codoping CsBaGd(MoO4)3 with Er3+/Yb3+ ions, we have obtained an upconversion phosphor exhibiting anti-Stokes luminescence in the range 400–700 nm under IR excitation (λex = 977 nm). The synthesized phosphor has been characterized by X-ray diffraction, differential thermal analysis, and vibrational spectroscopy, and its luminescence spectrum has been measured. [ABSTRACT FROM AUTHOR]

Phase equilibria in the CaO-TaO 2.5 -YO 1.5 system were experimentally investigated and the isothermal section at 1400 °C was constructed. Ten three-phase equilibrium fields were determined, and the solid solution regions of the binary compounds were analyzed. The Ca 4 Ta 2 O 9 in the ternary system is marked as (YO 3/2) x (Ca 2/3 Ta 1/3 O 3/2) 1−x. Its maximum solubility is the formula of Ca 2 YTaO 6. The solubilities of CaO in the M′-YTaO 4 and fluorite phases reach up to about 2.0 mol% and 8.9 mol%, respectively. A ternary pyrochlore-type phase was found, which was expressed as the chemical formula of Ca 0.5–0.5x Y 0.75x Ta 0.5–0.25x O 1.75. The morphology of pyrochlore was polygonal, and it was the only reaction product when the YTaO 4 oxides were corroded by the molten silicate (CMAS). Since the CaO is the main reactant, the CaO-TaO 2.5 -YO 1.5 phase diagram was used to successfully explain the corrosion behavior of YTaO 4. The current experimental phase diagram is important to understand the CMAS degradation of the thermal barrier coatings. [ABSTRACT FROM AUTHOR]

The recent results of the accurate calorimetric measurements of phase equilibria in ternary mixtures of methane, propane, and nonane have been presented. The heat capacity, internal energy, pressure, and temperature derivative of pressure at constant volume were measured in the range 160–340 K, up to 30 MPa. The phase transitions were localized by the finite discontinuities in temperature derivatives of the thermodynamic potentials. The phase diagrams for ternary mixtures of methane, propane, and nonane have been plotted based on the experimental data. These data are supplemented with the earlier measurements of two ternary hydrocarbon systems for the low concentration of octane and decane. Our investigations show that hydrocarbon mixture for the low concentration of nonane as well as the hydrocarbon mixtures for the low concentration of octane and decane split into two phases, the nonane-lean macrophase and the microphase formed by nonane. Besides, nonane provokes a split of the liquid part of a ternary mixture into two liquid phases, the nonane-rich phase and the nonane-lean phase. [ABSTRACT FROM AUTHOR]