Topological characterization of the Bi-Ge-Te phase diagram

The available phase-diagram data for the Bi-Ge-Te, Ge-Te, Bi-Te, and Ge-Bi systems are critically evaluated. A topological image of the Bi-Ge-Te phase diagram is constructed in the form of a graph, with the nodes representing distinct phases and edges representing two-phase mixtures, ordered with respect to temperature. The proposed topological approach is used to construct isothermal sections, the liquidus surface of the ternary system, andT-x sections.     

Magnetic properties and phase change features in Fe-doped Ge-Sb-Te

The relationship between magnetic property and phase change features in Fe-doped Ge-Sb-Te has been studied. Fe-doped Ge-Sb-Te is a phase change magnetic material, which exhibits a fast phase change feature and different magnetic, optical and electrical properties between amorphous and crystalline states. However, the crystallization temperature increases and crystallization rate drops with an increase of Fe doping content. Fe doping content should be less than the solid solubility limit so that Fe-doped Ge-Sb-Te has both magnetic property and phase change features. Fe-doped Ge-Sb-Te at crystalline state shows p-type conduction and has a high hole concentration. The Ruderman-Kittel-Kasuya-Yosida indirect interaction via carriers is the origin of the ferromagnetism in Fe-doped Ge-Sb-Te.     

T-x phase diagram of the In-S system

The T-x phase diagram of the In-S system has been studied by differential thermal analysis and x-ray diffraction between 300 and 1150°C. The compounds identified in this temperature range are InS, In₆S₇, In₃S₄, and In₂S₃. We have determined the temperatures of the monotectic equilibrium L ₁(In) + InS = L ₂; peritectic equilibria involving InS, In₆S₇, and In₃S₄; and polymorphic transformations of InS and In₂S₃. Our results demonstrate that raising the cooling rate to a certain level leads to a sharp transition from near-equilibrium to metastable phase relations in the In-S system.     

The phase diagram of the solid methanes

A comparative study is presented of the phase diagrams of the solid methanes CH₄, CH₃D, CH₂D₂, CHD₃, and CD₄ obtained experimentally using NMR techniques at pressures up to 9 kbar. Polynomial representations of the I–II, I–III and II–III phase transition lines are given. The experimental conditions under which solid methane transforms to phase IV are discussed and polynomial representations of the I–IV, the IV–I, and the IV–II transition lines are also given.     

Refinement of the In-S phase diagram using spectrophotometric characterization of equilibria between hydrogen and indium sulfides

A spectrophotometric procedure for hydrogen sulfide determination has been developed and utilized to study the phase diagram of the In-S system using hydrogen as an auxiliary component. Elemental analysis of the hydrogen-containing vapor phase allows the principal thermodynamic properties of the indium sulfides in equilibrium with the vapor phase to be assessed in wide temperature and composition ranges. Our results confirm the existence of a narrow two-phase field between In_3?x S₄ and In₂S′₃ (low-temperature phase), which is bounded from above by the peritectic decomposition temperature of (about 415°C). We have determined the temperature-dependent sulfur (S₂) vapor pressure over condensed indium sulfides. For the equilibria studied in greatest detail, the present results correlate well with mass spectrometry data for indium sulfides.     

On the phase diagram of the system hydroxypropylcellulose-water

The phase diagram of the system hydroxypropylcellulose (HPC)-H₂O has been investigated using differential scanning calorimetry (DSC), X-ray diffraction, optical microscopy and¹H (NMR) nuclear magnetic resonance spectroscopy. A peritectic line at higher temperatures has been found similar to the lytropic systems described before. This phase transition, from a solution consisting of solvate aggregates and free solvent, into a crystal solvate-isotropic phase system is completely reversible. The formation of crystal solvate phases is independent of the water content of the system until the system transforms into a thermotropic system. The solvent molecules are strongly associated with the macromolecules.     

Condensed phase diagram for the In-As-O system

An estimate of the condensed phase portion of the equilibrium In-As-O ternary diagram has been constructed from thermodynamic calculations and checked against binary mixture reaction experiments. Utilization of the diagram to explain the phase composition of thin films associated with thermal oxidation and native oxide-substrate reaction processes on InAs and In_xGa_1-xAs are presented in a companion paper.     

High-temperature phase diagram of sodium chloride

The critical point is calculated and a high-temperature phase diagram is constructed for sodium chloride with allowance for the structural phase transition between B1 and B2 polymorphs of NaCl crystal.     

Investigation of the phase diagram of the Pb-Ga-Sb system

The growth of GaSb and its solid solutions from ‘neutral’ solvents could be useful to improve the characteristics of these materials. Pb can be used as such a ‘neutral’ solvent. The phase diagram of the system Pb-Ga-Sb was determined experimentally in a region where it could be used for liquid phase epitaxy. The results are compared with the calculated phase diagram. Photoluminescence characteristics and secondary ion mass spectroscopy analysis of samples grown from Pb containing liquid phases are discussed.     

Tungsten carbides and W-C phase diagram

The crystal structures of the tungsten monocarbide δ-WC and the disordered lower carbide β-W₂C are studied. Using magnetic susceptibility measurements, the hexagonal carbide δ-WC is shown to be stable from 300 to 1200 K. The sequence of phase transformations associated with β-W₂C ordering is analyzed. The temperature and composition stability limits of the cubic carbide γ-WC_1?x are evaluated, and the first data are presented on the variation of its lattice parameter with composition. An optimized W-C phase diagram is proposed which takes into account detailed structural and phase-equilibrium data for tungsten carbides.     

500°C section of the Pr-Ag-Sb phase diagram

The 500°C phase relations in the Pr-Ag-Sb system have been studied by x-ray diffraction. The existence of the ternary compound PrAgSb₂ has been confirmed, and its structure has been refined by the Rietveld method (sp. gr. P4/nmm, structure type HfCuSi₂, a = 0.43473(2) nm, c = 1.06711(8) nm, R _I = 0.080, R _p = 0.148).