Phase relations in the CuI-SbSI-SbI3 composition range of the Cu–Sb–S–I quaternary system

The phase equilibria in the Cu-Sb-S-I quaternary system were studied by differential thermal analysis and X-ray phase analysis methods in the CuI-SbSI-SbI3 concentration intervals. The boundary quasi-binary section CuI-SbSI, 2 internal polythermal sections of the phase diagram, as well as, the projection of the liquidus surface were constructed. Primary crystallisation areas of phases, types, and coordinates of non- and monovariant equilibria were determined. Limited areas of solid solutions based on the SbSI (b-phase) and high-temperature modifications of the CuI (α1- and α2- phases) were revealed in the system. The formation of the α1 and α2 phases is accompanied by a decrease in the temperatures of the polymorphic transitions of CuI and the establishment of metatectic (3750C) and eutectoid (2800C) reactions. It was also shown, that the system is characterised by the presence of a wide immiscibility region that covers a significant part of theliquidus surface of the CuI and SbSI based phases

PHYSICO-CHEMICAL INTERACTION OF THE COPPER AND ANTIMONY IODIDES

The character of the mutual interaction of the components in the CuI-SbI3 system was studied by differential thermal analysis and X-ray phase analysis methods and its phase diagram was constructed. It was found that the system is quasi-binary and forms a monotectic phase diagram. The immiscibility region covers ~15-93 mol% SbI3 concentration interval at the monotectic equilibrium temperature (~ 4930С). The temperatures of polymorphic transformations of the CuI compound in the system drop slightly and these phase transitions take place by metatectic reactions

LIQUID-LIQUID EQUILIBRIA OF THE WATER+ETHANOL+DIMETHYL ADIPATE TERNARY SYSTEM

Liquid-liquid equilibrium data for the terna1y system water-ethanol-dimethyl adipate (dibasic ester) have been determined experimentally at 298.15±0.20, 308.15±0.20, and 318.15±0.20 K. Tie-line compositions were correlated by the Othmer-Tobias method. The UNIFAC method was used to predict the phase equilibrium in the system using the interaction parameters determined from experimental data between the CH3, CH2, OH, CH3COO and H20 groups. Distribution coefficients and separation factors were evaluated for the immiscibility region

Calculation of metastable immiscibility region in the Al2O3–SiO2 system using molecular dynamics simulation

The metastable immiscibility region in the Al2O3–SiO2 system was calculated by conventional thermodynamic equations using thermodynamic parameters obtained from molecular dynamics simulation. The calculated miscibility gap has a consolute temperature of around 1500 °C at the critical composition of about 20 mol% Al2O3 and spreads more widely towards the Al2O3-rich composition side than the SiO2-rich side. The calculated miscibility gap in this study showed a fair agreement with that reported by Ban et al. [T. Ban, S. Hayashi, A. Yasumori, and K. Okada, J. Mater. Res. 11, 1421 (1996)] calculated by a regular solution model, but the present calculated region is somewhat narrower in the Al2O3-rich composition side than that reported by Ban et al.

Calculation of metastable immiscibility region in the Al2O3–SiO2 system

Metastable liquid-liquid immiscibility region in the Al2O3–SiO2 system was calculated by a regular solution model using three sets of liquidus data from the stable phase diagrams reported. These calculations indicated that the immiscibility region was richer in Al2O3 composition than those reported before. A miscibility gap calculated using the liquidus data reported by Klug et al. [F. J. Klug, S. Prochazka, and R. H. Doremus, J. Am. Ceram. Soc. 70, 750 (1987)] (model A) ranged from 2.6 to 71 mol % Al2O3 at around 1000 °C, which was the most compatible result with the idea that metastable pseudotetragonal mullite crystallized at around 1000 °C became Al2O3-rich composition due to the immiscibility phase separation before mullitization among three sets of liquidus data.

Microstructural development of rapidly solidified, phase-separated SiO2-Al2O3 glass

A metastable miscibility gap has been shown to exist oyer much of the SiO2(s) -mullite(s) phase field by various indirect methods. The various proposed boundaries of this liquid-liquid immiscibility region, however, significantly disagree in their widths and critical point positions. The overall aim of our research is to directly determine the miscibility gap boundaries by using TEM/EDS on suitably equilibrated phases of rapidly solidified SiO2-Al2O3 glass. Rapid solidification by roller quenching (∼106°C/sec) and by ice- water quenching (~1035°C/sec) was used so that a wide range of compositions could be studied. SiO2-Al2O3 melts with more than ∼30 wt% Al2O3 readily crystallize when slowly cooled. A suitable microstructure for EDS requires homogeneous phases that are separated by sharp interfaces, and are large enough to withstand beam damage. In an attempt to meet these requirements, the as-quenched glass microstructures were developed by annealing for various times at suitable temperatures.