Freezing point and heating curve behavior for an organic reciprocal salt pair system

Binary and quasi-binary freezing point data have been obtained to establish the freezing point diagram for the ternary reciprocal salt pair system involving cyclohexylamine stearate, cyclohexylamine palmitate, 2,2'-dipyridylamine stearate, and 2,2'-dipyridylamine palmitate. The compositions and primary freezing points of the ternary peritectic and eutectic mixtures have been determined Apparent anomalies in the heating curves for selected compositions have been explained on the basis of the existence of metastable equilibria.     

Investigation of the United stable tetrahedron LiF-KBr-K2MoO4-KF of the quaternary reciprocal system Li,K‖F,Br,MoO4

The united stable tetrahedron LiF-KBr-K₂MoO₄-KF of the quaternary reciprocal system Li,K‖F,Br,MoO₄ was studied by differential thermal analysis. The melting points and ternary eutectic and peritectic compositions in the secant triangle LiF-KBr-K₃FMoO₄ were identified. The melting points of the samples corresponding to the quaternary invariant equilibrium points (eutectic and peritectic points) and their compositions in the stable tetrahedron LiF-KBr-K₃FMoO₄-KF were determined. The volumes of crystallizing phases in the united stable tetrahedron were determined; the phase equilibria at invariant points were described.     

SmCl~3-SrCl~2-MgCl~2体系相图的研究

利用DTA研究了SmCl~3-SrCl~2-MgCl~2三元体系相图。发现它有对应SmCl~3、SrCl~2、MgCl~2、SmSr~3Cl~9的四个液相面, 五条二次结晶线, 一个三元低共熔点E(41.8mol% SmCl~3, 30.7mol% SrCl~2, 500℃), 一个三元转熔点P(32.0mol% SmCl~3,39.3mol% SmCl~2, 520℃)。     

Phase diagram study of CaBr2–LiBr system using DTA

The phase diagram of binary LiBr–CaBr₂ system was investigated using differential thermal analysis (DTA) between room temperature and 800 °C. From the DTA results obtained over the entire range of composition from pure LiBr to pure CaBr₂ in steps of ~5 mol%, the phase diagram was constructed and is reported here. The results indicated the possible existence of a compound at 50 mol% LiBr, namely, LiCaBr₃. The compound undergoes peritectic decomposition at 552 °C. The system shows a eutectic reaction at 532 °C between this compound and LiBr phase, and the eutectic composition is close to 80 mol% LiBr. The compound LiCaBr₃ decomposes into CaBr₂ and LiBr phases below 272 °C. Co-existing phases in different phase fields are characterized by X-ray diffraction analysis.     

Phase equilibria in Cu-Al-Zr system at 1073 K and aluminum concentration of less than 55 at %

X-ray diffraction and electron probe microanalysis were used to investigate phase equilibria in the ternary Cu-Al-Zr system at 1073 K in the Zr-rich region. The fragment of the isothermal section of the system was plotted. The regions of homogeneity of the ternary ZrCu₂Al and ZrCu _x Al_{2 ? x} phases were investigated. The type of phase equilibria between binary and ternary compounds of the Al-Cu-Zr system was established. It was found out that, at a Zr concentration above 55 at %, ternary compounds are not formed, and the Zr₃Al and Zr₂Cu phases were in equilibria with ??-Zr at 1073 K.     

Phase diagram of a system of adipic,glutaric, and sebacic acids

Adipic acid–glutaric acid, glutaric acid–sebacic acid, and adipic acid–sebacic acid binary systems are studied, along with an adipic acid–glutaric acid–sebacic acid ternary system. It is shown all of these systems are eutectic. Phase equilibria for the diagram elements of the binary systems and the ternary system are described. It is concluded that the above low-melting compounds can be recommended for use as working bodies in heat accumulators, and for preparing electrolytes used in the thin-layer anodic oxidation of aluminum alloys.     

Experimental Study and 3D Modeling of the Phase Diagram of the Ag–Sn–Se System

In connection with the contradictoriness of literature data, phase equilibria in the Ag–Sn–Se system were restudied by differential thermal analysis and X-ray powder diffraction analysis. A number of polythermal sections and the isothermal section at room temperature of the phase diagram were constructed, and a projection of the liquidus surface was built. The primary crystallization fields of phases and the types and coordinates of in- and monovariant equilibria were determined. It was demonstrated that, in the system, two ternary compounds, Ag₈SnSe₆ and Ag_xSn_{2 – x}Se₂ (0.84 < x < 1.06), form. The former melts congruently at 1015 K and undergoes a polymorphic transformation at 355 K, and the latter melts with decomposition by a peritectic reaction at 860 K. The formation of the compound Ag₂SnSe₃, 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 limited number of samples of the ternary system, equations were obtained for calculation and 3D modeling of the liquidus and phase-separation surfaces.     

Phase equilibria in the aluminium-rich side of the Al–Zr system

The Al-rich phase equilibria in the Al–Zr binary system were investigated experimentally. The phase diagram for compositions up to 40 at.% Zr was determined experimentally by differential thermal analysis and metallography. Three stable intermetallic compounds exist in this region of the diagram: Al₃Zr₂, Al₂Zr, and Al₃Zr. The peritectic melting of Al₃Zr₂ and the congruent melting of Al₂Zr were confirmed. Al₃Zr, the most Al-rich intermetallic compound, melts peritectically, which contradicts information available in the literature. In addition, the reaction between Al₃Zr and the (Al) solid solution seems to be of eutectic nature, in contradiction with previous results found in the literature. Based on these new experimental evidence, a revised phase diagram is drawn.     

Topology of melting diagrams of ternary reciprocal systems without continuous solid solutions

The topological properties were considered for melting diagrams of ternary reciprocal systems with constant-composition phases or with isomorphic diagrams with limited solid solutions. An algorithm for constructing the diagrams was described, and an example was given for a melting diagram with one binary peritectic compound and two ternary stoichiometric compounds, all melting without decomposition. A problem of enumeration of all the phase diagrams with such a set of compounds was solved.     

Phase diagram for the ternary system LiClCaCl2CaCrO4

The phase diagram for the system LiClCaCl₂CaCrO₄ has been studied using differential thermal analysis. LiClCaCl₂CaCrO₄ has been shown by X-ray diffraction to be a stable, diagonal section of the Li, Ca//Cl, CrO₄ reciprocal ternary system. The three binary systems are: LiClCaCl₂ which exhibits a double salt (LiCaCl₃), which decomposes without melting at 439°C and a eutectic at 36.3 mole % CaCl₂ (m.p. 487°C); CaCl₂CaCrO₄ which shows a eutectic at 23.4 mole % CaCrO₄ (m.p. 660°C); and LiClCaCrO₄ with a eutectic at 14.3 mole % CaCrO₄ (m.p. 538°C).In the ternary system, a eutectic exists at 63.2 mole % LiCl32.9% CaCl₂3.9% CaCrO₄ (m.p. 479°C). In addition, a four-phase equilibrium, involving all solid phases, exists at nearly all compositions at 435°C.Isotherms are shown for the liquidus surface (primary crystallization) and for the secondary crystallization surface. Isothermal and vertical sections through the ternary phase diagram are shown.     

Comparison of Prediction of Phase Equilibria in the Ag–In–Sb System at 200°C with Experimental Data

Summary. Binary thermodynamic data, successfully used for phase diagram calculations of binary systems Ag–In, Ag–Sb, and In–Sb, were used for prediction of phase equilibria in ternary Ag–In–Sb system at 200°C. Symmetrical Redlich–Kister–Muggianu model for ternary thermodynamic function calculation was proved to be best valid in this ternary system. Predicted equilibria were compared with experimentally (SEM, EDX) determined composition of phases in chosen alloys after long term annealing and with the results of DTA measurements.     

Comparison of Prediction of Phase Equilibria in the Ag–In–Sb System at 200°C with Experimental Data

Binary thermodynamic data, successfully used for phase diagram calculations of binary systems Ag–In, Ag–Sb, and In–Sb, were used for prediction of phase equilibria in ternary Ag–In–Sb system at 200°C. Symmetrical Redlich–Kister–Muggianu model for ternary thermodynamic function calculation was proved to be best valid in this ternary system. Predicted equilibria were compared with experimentally (SEM, EDX) determined composition of phases in chosen alloys after long term annealing and with the results of DTA measurements.     

Partial phase diagrams for the water—cadmium nitrate, water—silver nitrate and water—cadmium nitrate—silver nitrate systems

Sub-ambient differential scanning calorimetry has been used to determine partial binary phase diagrams for the water—silver nitrate and water—cadmium nitrate systems. Both systems are shown to be eutectic with eutectic temperatures of 263 ± 0.5 K and 256.5 ± 0.5 K for the water—silver nitrate and water—cadmium nitrate systems, respectively. The eutectic compositions are at approximately 40.5 wt.% nitrate for each system. The freezing of ternary solutions containing a fixed silver nitrate/cadmium nitrate ratio but increasing concentrations of total nitrates are explained in terms of a partial ternary system containing two binary eutectic systems and a ternary eutectic reaction. The ternary eutectic temperature is shown to be 254 ± 0.5 K.     

The CaF2-CaCl2-CaSO4 system

The liquidus surface of the CaF₂-CaCl₂-CaSO₄ system has been investigated by differential thermal analysis. Two invariant equilibria (one eutectic and one peritectic) are realized in the system. The eutectic and peritectic melt at 597 and 703°C, and the enthalpies of phase transitions are 206 and 378.1 kJ/kg, respectively. Investigation of the ternary system formed by the natural minerals fluorite (CaF₂), anhydrite (CaSO₄), and calcium chloride (a relatively low-melting inorganic solvent) is undertaken with the goal of developing power-intensive heat-accumulating phase-transition materials and electrolytes of diversified application. Original Russian Text ? P.A. Arbukhanova, Ya.A. Dibirov, N.N. Verdiev, A.M. Amadziev, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 6, pp. 1043–1045.     

Diagramme de phases du systeme binaire LiNO3-NaNO3

Phase diagram of the binary system LiNO₃-NaNO₃ has been obtained by using direct and differential thermal analysis between 323 and 623 K. This system is characterized by an eutectic plateau at 467 K. The eutectic point is at 0.465 mole NaNO₃. A peritectic appears at 550 K. There is no miscibility in the solid state. These findings associated with some other thermodynamic results have been used to calculate the activities of the constituents along the liquids curve and the excess thermodynamic functions at 618 K. The constituents seem not to have a symmetrical influence on the thermodynamic quantities.

     

YbCl3-MCln体系相图的研究(M=Li、Mg、Ca、Pb; n=1,2)

借助于DTA与X射线衍射法研究了YbCl_3-MCl_n(M=Li、Mg、Ca、Pb; n=1或2)二元体系相图．发现YbCl_3-LiCl体系相图属固液异组成型，有化合物Li_3YbCl_6生成，它在481 ℃有一相转变. 其无变点分别为x_(YbCl_s)＝0.410；526 ℃和x_(YbCl_3)=0.340，547 ℃；YbCl_3-MgCl_2属类转熔型相图，在富YbCl_3相区666 ℃有一尚不知其性质的热效应，为x_(YbCl_3)＝0.380，628 ℃；YbCl_3-CaCl_2和YbCl_3-PbCl_2体系皆属简单低共熔型相图，其低共溶点分别为x_(YbCl_3)＝0.530, 615 ℃和x_(YbCl_3)＝0.340, 415 ℃. 后者在固相下有一不稳定化合物PbYbCl_5生成，在392 ℃分解，同时探讨了相图的某些规律．