The phase diagram of KNO3–RbNO3

The phase diagram of the binary system KNO₃–RbNO₃ was studied using simultaneous direct and differential thermal analysis technique and differential scanning calorimetry. This system exhibits six invariants: a eutectic at 293 °C, four eutectoïd reactions at 109, 157, 159, and 291 °C, respectively, and a peritectoïd one at 288 °C.     

Partial phase diagram of the PuCl3PuOCl system

Phase equilibria in the system PuCl₃PuOCl were studied over the temperature range 100–1300°C and composition range 0–35 mole% PuOCl by thermal analysis and differential thermal analysis techniques, supplemented by X-ray powder diffraction analysis. A single eutectic was found at 747° and 8 mole % PuOCl. No evidence of compound or solid solution formation was observed.     

A study on the phase diagram of AlF3CsF system

Phase relations of the AlF₃CsF system have been investigated by the methods of DTA and XRD with quenching technique. Four compounds were identified: Cs₃AlF₆, CsAlF₄, CsF·2AlF₃ and CsF·3AlF₃. Cs₃AlF₆ melts congruently at 790°C. The first eutectic, E₁, between Cs₃AlF₆ and CsF is located in 10.0 mol% AlF₃ at 654°C. CsF·2AlF₃ and CsF·3AlF₃ melt incongruently at 508° and 653°C, respectively. The second eutectic, E₂, was observed in 42.0 mol% AlF₃ at 471°C. The compound CsAlF₄ formed in the solid eutectic when cooled below 443°C. CsAlF₄ has α and β forms, transformation of which takes place reversibly at 422°C. All phase structures in the system were confirmed by X-ray powder diffraction analysis.     

Phase diagram and electrical conductivity of the CeBr3–CsBr binary system

Journal of Thermal Analysis and Calorimetry - Phase equilibrium in the CeBr3–CsBr binary system was established from differential scanning calorimetry (DSC). This system includes three...     

The revised phase diagram of the Ca3(PO4)2–YPO4 system. The temperature and concentration range of solid-solution phase fields

A revised version of the Ca₃(PO₄)₂–YPO₄ phase diagram has been proposed on the basis of results obtained by thermal analysis (DTA/DSC/TG) and X-ray diffraction methods. A limited solid solution with the structure of β-Ca₃(PO₄)₂ exists in the system. At 1,100 °C the maximal concentration of YPO₄ in the solid solution is ~15 mass%. The solid-solution phase field exists in the temperature range upto ~1,380 °C. Two high-temperature solid solutions with the structure of α′ and α-Ca₃(PO₄)₂ form in system as well, however only the α phase can be obtained by quenching from high temperatures. The Ca₃Y(PO₄)₃ compound with the structure of eulytite forms in the Ca₃(PO₄)₂–YPO₄ system at temperatures exceeding 1,255 °C and does not show any polymorphic transition.     

Study and 3D modeling of the phase diagram of the Ag–Ge–Se system

In view of the contradictoriness of the literature data, phase equilibria in the Ag–Ge–Se system were restudied by differential thermal analysis and X-ray powder diffraction analysis. A number of polythermal sections and an isothermal section at room temperature of the phase diagram were constructed, and so was the projection of the liquidus surface. The primary crystallization fields of phases and the types and coordinates of in- and monovariant equilibria were determined. It was shown that, in the system, a single ternary compound, Ag₈GeSe₆, forms, which undergoes congruent melting at 1175 K and a polymorphic transformation at 321 K. The formation of the compounds Ag₂GeSe₃ and Ag₈GeSe₅, which was previously reported in the literature, was not confirmed. Based on the phase diagrams of boundary binary systems and the results of the differential thermal analysis of a number of samples of the ternary system, equations were obtained for calculation and 3D modeling of the liquidus and phase-separation surfaces.     

Determination of the phase diagram of the MoCo system using diffusion couples

The phase diagram of the MoCo system between 800 and 1300°C has been investigated by microscopy, X-ray diffraction and electron-probe micro-analysis, using diffusion couples consisting of the pure metals or their alloys. The μ (Mo₆Co₇) phase has a constant homogeneity range of 7 at.% (51.5–58.5 at.% Co). The θ phase (discovered by Quinn and Hume-Rothery²) is stable between 1018 and 1200°C. Its Mo-rich boundary is found at 81 at.% Co. The Co-rich boundary shifts from 83 at.% Co at 1050°C to 81 at.% Co at 1200°C. The K phase found up to 1000°C has a homogeneity range of 75–76.5 at.% Co. The σ phase is found at and above 1000°C at a composition of about 36 at.% Co. The σ layers were too thin for an accurate determination of the phase boundary concentrations. Co can dissolve 19.5 at.% Mo, and Mo only 1.5 at.% Co at 1300°C.     

The Nb-rich part of the NbGa phase diagram

Ten alloys in the composition range 11–40 at.% Ga were produced by a four-stage process that involved both sintering and melting stages. These alloys were heat-treated at temperatures in the range 700–1600 °C until equilibrium was attained. The phases present after heat treatment were studied by means of X-ray diffraction, electron probe microanalysis and light microscopy. From the data obtained, the temperature dependence of the solubility limit of gallium in niobium was determined, the homogeneity range of Nb₃Ga was defined, and the second most niobium-rich compound was identified as oxygen-stabilised Nb₅Ga₃O_x.     

Thermodynamic performance of the NaNO3–NaCl–NaNO2 ternary system

Calculations of phase diagram for additive ternary molten salt system are carried out by the conformal ionic solution theory. The liquidus temperatures of the system NaNO₃–NaCl–NaNO₂ are determined according to different types of solid–liquid equilibrium and different values of the binary interaction coefficients. For the system NaNO₃–NaCl–NaNO₂, the calculated and experimental temperatures differ are very small below 673 K, but the oxidation and decomposition of the mixed salts are found when the temperature is higher than 673 K. Meanwhile, the eutectic point is obtained from calculated phase diagram and the eutectic temperature is 507 K. Thermal stability of this eutectic mixture is investigated by thermo-gravimetric analysis device. Experimental results show this kind of molten salt has a lower melting point (501.28 K), similar to solar salt (493 K). It is thermally stable at temperatures up to 819 K, and may be used up to 827 K for short periods.     

The phase diagram of the Ga–S system in the concentration range of 48.0–60.7 mol% S

Journal of Thermal Analysis and Calorimetry - A novel flame-retarded epoxy resins system is prepared by copolymerizing diglycidyl ether of bisphenol A (EP) with tris(3-nitrophenyl) phosphine...     

Re-investigation of the La–Mg phase diagram

Literature results on the La–Mg binary system are critically reviewed. It is shown that most recent experimental results are not in agreement with the previously published assessments of the system. Thus, an experimental re-investigation of this phase diagram is required. Several alloys are synthesized from pure constitutive elements and characterized using X-ray diffraction, scanning electron microscopy, and differential thermal analysis. This study clarifies the phase equilibria in the La–Mg system. These results combined with the recent study of the enthalpies of formation of the intermediate compounds of this system provide a sound basis for the Calphad optimization of the system.     

Investigation of the CuBr–LiBr phase diagram

Phase diagram for the system CuBr–LiBr was determined by differential scanning calorimetry and X-ray powder diffraction. The system exhibits a significant solid solubility of the components, especially LiBr in the respective polymorphic modifications of CuBr. Another feature of the system CuBr–LiBr is the occurrence of five invariant three-phase equilibria, which have been assigned to one eutectic (684 K), one peritectoid (668 K), and three eutectoids (679, 645, and 521 K). From the experimental results, formation of a compound LiCuBr₂, at 521 K is discerned.