Thermodynamic properties of alloys of the binary In–Yb system

The thermochemical properties of melts of the binary In–Yb system were studied by the calorimetry method at 1160–1380 K over the whole concentration interval. It was shown that significant negative heat effects of mixing are characteristic features for these melts. Using the ideal associated solution (IAS) model, the activities of components, Gibbs energies and the entropies of mixing in the alloys, and the phase diagram of this system were calculated. They agree with the data from literature.     

Thermodynamic description of the aluminum–rhenium system

Journal of Thermal Analysis and Calorimetry - Phase relationships in the Al–Re binary system have been thermodynamically reassessed by using the CALPHAD technique to take into account the...     

Thermodynamic and transport properties of the DyBr3–NaBr binary system

Phase equilibria in the DyBr₃–NaBr binary system were established from differential scanning calorimetry. This system exhibits incongruently melting compound Na₃DyBr₆ and one eutectic located at DyBr₃ molar fraction x = 0.409 (T = 711 K). Na₃DyBr₆ undergoes a solid–solid phase transition at 740 K and melts incongruently at 762 K. The specific conductivity of DyBr₃–NaBr liquid mixtures was measured over the whole composition range. Results obtained are discussed in term of possible complex formation.     

Thermodynamic reassessment of the Al–Zr binary system

Journal of Thermal Analysis and Calorimetry - Based on the data of the literature reports, the Al–Zr binary system has been re-assessed thermodynamically through the CALPHAD (CALculations of...     

Thermodynamic Properties of Alloys of the Sn–Yb System

Thermochemical properties of liquid alloys of the Sn–Yb system are studied via calorimetry at 1110–1310 K over the ranges of concentrations 0 < x_Yb < 0.47 and 0.82 < x_Yb < 1. Considerable negative heat effects of the mixing of these alloys are identified. Activities of the components, the Gibbs energies and entropies of mixing, and the liquidus curve of the phase diagram of this system are calculated using the ideal associated solution (IAS) model and agree with data from the literature.     

Thermodynamic properties of alloys of the binary In–La system

The thermochemical properties of melts of the binary In–La system were studied by the calorimetry method at 1250–1480 K over the whole concentration interval. It was shown that significant negative heat effects of mixing are characteristic features for these melts. Using the ideal associated solution (IAS) model, the activities of components, Gibbs energies and the entropies of mixing in the alloys, and the phase diagram of this system were calculated. They agree with the data from literature.     

Thermodynamic properties of the NdBr3–MBr binary systems (M = Na,K)

Thixoforming involves heating different types of alloys to the semisolid state at high heating rates and forming in die-casting machines or conventional presses. At temperatures higher than the solidus and lower than the liquidus, the mush metal behaves like a high-viscosity thixotropic material. Therefore, determining the thermodynamic behavior of the solid-to-liquid transition is paramount to control thixoforming processes. This article describes a simple, novel experimental setup based on differential thermal analysis (DTA) for analyzing the phase transitions in an alloy heated using high heating rates typical of industrial applications. A365 alloy was chosen to demonstrate the effectiveness of the method as the phase transformations for this alloy in semisolid materials (SSM) processing are well understood. Samples were heated to 750 °C using constant linear heating rates of 5, 10, 15, 20, 25, 50, 75, 100 and 125 °C min in a Norax 25 kW 8 kHz induction furnace with an Omron E5CK temperature controller. AISI 316 austenitic stainless steel was used as the inert reference. Comparison of the results of DTA using the proposed method and the results of simulation with Thermo-Calc^® indicates that the proposed in situ DTA device and its method is suitable for analyzing phase transitions when high heating rates are used.     

Thermodynamic modelling of liquid-vapour equilibrium and thermophysical properties of molten Pb–Bi systems

A lead–bismuth alloy is an advanced coolant for nuclear power plants. The study of this alloy is of current importance. However, performing high-temperature experiments involves many problems. In this work, to study evaporation of a lead–bismuth alloy in the presence of intermetallic compounds in the condensed phase and dimers and trimers of metals in the vapour phase, a method of thermodynamic modelling was used. The investigations were carried out at temperatures from 400 to 3000 K with the lead content from 0.1 to 0.9 weight fractions in the lead–bismuth alloy. In the method of thermodynamic modelling a software package TERRA and a model of an ideal solution of interaction products were applied. Concentration and temperature dependencies of the content of components in the melt and in the gaseous phase over the melt were calculated. Temperatures, enthalpies, entropies of the melt–vapour transition and various thermophysical properties were defined.     

Thermodynamic Properties of Alloys of the Binary Bi—Yb System

The thermochemical properties of melts of the binary Bi—Yb system were studied by the calorimetry method over the concentration ranges 0 < x_Yb < 0.43 at 1000–1270 K and 0.8 < x_Yb < 1 at 1100–1140 K. It was shown that significant negative heat effects of mixing are characteristic features for these melts. A range 0 < x_Yb < 0.19 of the Bi—Yb phase diagram was investigated by the DTA method. Using the regular associated solution (RAS) model, the activities of components, Gibbs energies and the entropies of mixing in the alloys, and the phase diagram of this system were calculated. They agree with the data from literature.     

X-ray fluorescence analysis of the systems Fe–Ni–Mo/Cr

A procedure has been developed for the X-ray fluorescence determination of the thickness of Fe-No-Mo/Cr two-layer films supported on polycor. Correction coefficients have been calculated that take into account the effects of the mutual influence of the elements in this system. The density of the materials in the films has been experimentally determined. The performance characteristics of the developed procedure are provided.     

Effect of binary extractants and modifier–diluents systems on equilbria of propionic acid extraction

Propionic acid is an important carboxylic acid widely used in chemical industries. The recovery from aqueous waste streams and fermentation broth is of research interest. Extraction of carboxylic acids by reactive extraction using extractant-diluent, mixed extractants in diluents and extractants in mixed diluents etc. are emerging areas of study. With this aim reactive extraction of propionic acid was carried out to study: (i) effect of binary extractants (tri-n-octylamine(TOA):tri-n-butylphosphate (TBP), TOA:Aliquat 336 and TBP:Aliquat 336), (ii) effect of modifier (1-decanol) in different diluents (kerosene, n-octane, n-heptane, petroleum ether, butyl acetate, MIBK, 2-octanol, dodecanol, hexane) and (iii) effect of phase volume. Improved extractions using binary extractants and binary diluents were observed. Since liquid–liquid extraction is dependent on effect of modifier concentration, effect of phase volume, presence of single or binary extractants and binary diluents, the study will be useful in the design of reactive extraction process for propionic acid recovery.