New Phase in the Bi–Sr–Ca–Cu–O System

Cooling a melt of a Bi–Sr–Ca–Cu–O system (Bi:Sr:Ca:Cu = 4:3:3:4 or 2:2:2:4) from 1000°C-1050°C yielded crystals of a new red-colored nonsuperconducting phase, accompanying the superconducting 2212 and 2201 phases. Based on the EPR spectra, it was concluded that copper is univalent in this compound. The new phase has a composition Bi_2.2Sr_1.6Ca_1.3Cu₂Ox. The X-ray diffraction pattern has been indexed, and the unit cell parameters of the phase have been determined: space group P2/m, a = 12.93, b = 4.55, c = 10.94 ; = 102.72°.     

Phase equilibria involving solid solutions in the Li–Mn–O system

Phase equilibria involving LiMn₂O_4-, Li₂MnO_3-, LiMnO_2-, Mn₃O_4-, and MnO-base solid solutions were studied with varied temperature and partial oxygen pressure. The \({P_{{o_2}}}\)–T and x–y projections of the P–T–x–y phase diagram of the Li–Mn?O system were constructed, as well as the key x–y isotherms of the Li₂O–MnO–MnO₂ quasi-ternary system. In some experiments, the authors’ hydride lithiation method was employed to prepare lithium-rich homogeneous three-component nonstoichiometric phases.     

Reinvestigation of Phase Equilibria in the V2O5–ZnO System

A diagram of phase equilibria established in a two-component oxide system V_{2 5}–ZnO has been worked out applying differential thermal analysis and X-ray phase analysis as well as depending on investigations carried out with the aid of high-temperature X-ray attachment and scanning electron microscope linked to an X-ray microanalyser. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase diagram of the Pr–Mn–O system in composition–temperature–oxygen pressure coordinates

The phase relations in the Pr–Mn–O system were studied by the static method at lowered oxygen pressure in combination with thermal analysis and high-temperature X-ray diffraction. The equilibrium oxygen pressure in dissociation of PrMn₂O₅ and PrMnO₃ was measured, and the thermodynamic characteristics of formation of these compounds from elements were calculated. The Р–Т–х phase diagram of the Pr–Mn–O system was constructed in the “composition–oxygen pressure–temperature” coordinates.     

Study on Phase Relations in Zn3V2O8–ZnMoO4 System

The phase equlibria established in the Zn₃V₂O₈–ZnMoO₄ system over the whole component concentration range up to 1000°C have been investigated. A phase diagram has been constructed using the results of DTA and XRD methods. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase Equilibria in the System Fe2O3–V2O5 –WO3 in the Solid State

DTA and X-ray phase diffraction methods were used to construct a solidus area projection onto the component concentration triangle plane of the system Fe₂ O₃-V₂ O₅-WO₃. This revised version was published online in August 2006 with corrections to the Cover Date.     

Phase Equilibria in The System La2O3–K2O–P2O5

The ternary system La₂O₃–K₂O–P₂O₅ has been examined by thermal, X-ray, IR and microscopic methods. The existence of three double potassium-lanthanum phosphates, K₃La(PO₄)₂, KLa(PO₃)₄ and K₂La(PO₃)₅ has been confirmed, and the phase diagram of the ternary system La₂O₃–K₂O–P₂O₅ over the composition range LaPO₄–K₃PO₄–P₂O₅ has been determined. This revised version was published online in August 2006 with corrections to the Cover Date.     

Phase Relations in the Ni–Mn–Ga Ternary System and Aging Effect on Shape Memory Properties of Ferromagnetic Ni<Subscript>2</Subscript>MnGa Sputtered Films

Summary. Isothermal sections of the Ni–Mn–Ga ternary phase diagram at 1073 and 1273 K were investigated over a wide range of alloy compositions. The range of the β-Ni₂MnGa phase, its equilibria with the γ-(Mn, Ni), α′-Ni₃Ga, and γ-Ni₃Ga₂ phases, and the liquidus and solidus lines were determined experimentally. The aging effect on the shape memory effect (SME) of Ni₂MnGa sputtered films was also investigated. The two-way SME of the constraint-aged films was confirmed by the temperature change.     

Phase Diagram for the RbBr–CuBr System

The phase diagram for the RbBr–CuBr system has been determined. In the system two intermediate compounds are formed: RbCu₂Br₃, melting congruently at 537 K and Rb₃CuBr₄, melting incongruently at 544 K. The coordinates of the two eutectic points are: 501 K, 54 mole% CuBr and 522 K, 74 mole% CuBr. This revised version was published online in July 2006 with corrections to the Cover Date.     

High-Temperature Synthesis of Composite Materials Based on MAX Phases in the Cr–Mn–Al–C System

Russian Journal of Applied Chemistry - High-temperature synthesis of cast composite materials in the Cr–Mn–Al–C system with various ratios between the Cr2AlC MAX phase and...     

Phase Equilibria in the Ag–In–Pd System at 700°C

Summary. Phase equilibria in the Ag–In–Pd system were determined at 700°C based on experimental results for 21 alloys. A ternary compound T₁ (with the approximate composition AgInPd₂) was identified by XRD analysis. These data were compared with the results of a CALPHAD-type prediction, based on binary thermodynamic data only and a symmetrical Redlich–Kister–Muggianu model. The experimental results will serve as a basis for refined thermodynamic modeling of the different phases in this ternary system.     

Phase Equilibria in the Ni–Al–W System at 900°C

Summary. Multicomponent Ni-base alloys exhibit good mechanical properties even at elevated temperatures and they are widely used for industrial production of exertion-resistive parts of engines. These properties are mainly determined by the coexistence of a disordered γ matrix with a face centred cubic lattice and cuboidal domains of its ordered γ′ structure. Therefore it is useful to study phase equilibria in Ni-base systems, namely in the regions involving both mentioned phases. One of the conclusions of our recent work on Ni–Al–Cr–W system was a necessity of modification of selected thermodynamic parameters of the ternary Ni–Al–W subsystem in order to achieve a better agreement of our experimental observations with theoretical modelling. This involves new measurements of the microstructure of selected samples of the Ni–Al–W system at 900°C and the comparison of the results with existing literature data in order to confirm our conclusions on higher order system investigated before. It is a first step on the way to an assessment of the Ni–Al–W system, which has not been done before.     

Thermodynamics,structure and kinetics in the system Ga–O–N

Within the ternary system Ga–O–N we performed experimental and theoretical investigations on the thermodynamics, structure and kinetics of new stable and metastable compounds.We studied the ammonolysis of β-Ga₂O₃ at elevated temperatures by means of ex situ X-ray diffraction, ex situ neutron diffraction, and in situ X-ray absorption spectroscopy (XAS). From total diffraction pattern refinement with the Rietveld method we analyzed the anionic occupancy factors and the lattice parameters of β-Ga₂O₃ during the reaction. Within the detection limits of these methods, we can rule out the existence of a crystalline oxynitride phase that is not derived from wurtzite-type GaN. The nitrogen solubility in β-Ga₂O₃ was found to be below the detection limit of about 2–3 at.% in the anionic sublattice. The kinetics of the ammonolysis of β-Ga₂O₃ to α-GaN and of the oxidation of α-GaN to β-Ga₂O₃ was studied by means of in situ X-ray absorption spectroscopy. In both cases the reaction kinetics could be described well by fitting linear combinations of β-Ga₂O₃ and α-GaN spectra only, excluding that other crystalline or amorphous phases appear during these reactions. The kinetics of the ammonolysis can be described well by an extended Johnson–Mehl–Avrami–Kolmogorow model with nucleation and growth of GaN nuclei, while the oxidation kinetics can be modeled by a shrinking core model where Ga₂O₃ grows as a layer. Investigations by means of TEM and SEM support the assumptions in both models.To investigate the structure and energetics of spinel-type gallium oxynitrides (γ-galons) we performed first-principles calculations using density-functional theory. In addition to the ideal cubic γ-Ga₃O₃N we studied gallium deficient γ-galons within the Constant-Anion-Model.In highly non-stoichiometric, amorphous gallium oxide of approximate composition GaO_1.2 we found at a temperature around 670 K an insulator–metal transition, with a conductivity jump of seven orders of magnitude. We demonstrate through experimental studies and density-functional theory calculations that the conductivity jump takes place at a critical gallium concentration and is induced by crystallization of stoichiometric β-Ga₂O₃ within the metastable oxide matrix. By doping with nitrogen the critical temperature and the conductivity in the highly conducting state can be tuned.     

Phase Diagram of the Ethylene Glycol–Dimethylsulfoxide System

The phase diagram of ethylene glycol (EG)–dimethylsulfoxide (DMSO) system is studied in the temperature range of +25 to ?140°C via differential scanning calorimetry. It is established that the EG–DMSO system is characterized by strong overcooling of the liquid phase, a glass transition at ?125°C, and the formation of a compound with the composition of DMSO · 2EG. This composition has a melting temperature of ?60°C, which is close to those of neighboring eutectics (?75 and ?70°C). A drop in the baseline was observed in the temperature range of 8 to ?5°C at DMSO concentrations of 5–50 mol %, indicating the existence of a phase separation area in the investigated system. The obtained data is compared to the literature data on the H₂O–DMSO phase diagram.     

Phase Equilibria in the System YPO4–K3PO4–KMgPO4

The phase equilibria in the part of the ternary system YPO₄–K₃PO₄–Mg₃(PO₄)₂ over the composition range YPO₄–K₃PO₄–KMgPO₄ were examined and determined by differential thermal analysis, X-ray powder diffraction and microscopic analysis in reflected light. This revised version was published online in August 2006 with corrections to the Cover Date.     

Melt–Vapor Phase Diagram of the Te–S System

The values of partial pressure of saturated vapor of the constituents of the Те–S system are determined from boiling points. The boundaries of the melt–vapor phase transition at atmospheric pressure and in vacuum of 2000 and 100 Pa are calculated on the basis of partial pressures. A phase diagram that includes vapor–liquid equilibrium fields whose boundaries allow us to assess the behavior of elements upon distillation fractioning is plotted. It is established that the separation of elements is possible at the first evaporation–condensation cycle. Complications can be caused by crystallization of a sulfur solid solution in tellurium.     

Phase Transitions in the BaCe1–x Nd x O3–δ System (x = 0–0.15)

Phase transitions in BaCe_{1 – x} Nd _x O_3– (x = 0–0.15) are studied on ceramic samples by dilatometry (at 370–1100 K) and by measuring electroconductivity (at 750–1220 K). Ion transport numbers are measured by an EMF method at 850–1240 K. All measurements are done in dry air (₂ 40 Pa). By treating the obtained temperature dependences of linear expansion with a difference method (difference between first-degree polynomial approximating the dependence and experimental points), the position and the sort of the phase transitions are determined. High-temperature phase transitions are confirmed by measuring the electroconductivity and ion transport numbers. Second-order phase transitions in pure BaCeO₃ are discovered at 480 ± 10, 530 ± 10, 900 ± 10, 1030 ± 20, and 1170 ± 10 K and a first-order transition, at 665 ±10 K. Phase transitions at 900 and 1030 K are discovered for the first time ever.     

Phase Equilibria in the System V2O5–Fe8V10W16O85 and Some Properties of the Fe8V10W16O85 Phase

A phase diagram of the V₂O₅–Fe₈V₁₀W₁₆O₈₅ system were carried out using XRD and DTA methods. In addition, an indexing of Fe₈V₁₀W₁₆O₈₅ powder diffraction pattern was made and its basic crystallographic parameters were determined. Finally, the phase was studied using IR spectroscopy. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase Diagram of the AgNO3–CsNO3 System

The phase diagram of the binary AgNO₃–CsNO₃ system was constructed using differential thermal analysis (DTA) technique in the range 300–700 K. The apparatus is described briefly. The results exhibit a congruently melting compound CsNO₃·AgNO₃ (m.p.=453 K) characterized by two allotropic varieties and , an incongruently melting compound AgNO₃·CsNO₃ (m.p.=450 K) with three forms , and , two eutectics (16 mol% CsNO₃, 442 K and 32.5 mol% CsNO₃, 445 K) and a peritectic (38mol% CsNO₃, 450 K). The occurrence of the transitions of intermediates was confirmed by X-ray diffraction at variable temperatures. The phase diagram exhibits also two plateaus at 429 K and 435 K corresponding to the phase transitions of CsNO₃ and AgNO₃, respectively.This revised version was published online in November 2005 with corrections to the Cover Date.