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Phase equilibrium diagrams of fluid phases in ternary systems can have a high complexity. In this work, a strategy and calculation methods for the computation of complete sections of ternary fluid phase equilibrium surfaces is proposed. To illustrate the methodology, we present computed results for the fluid phase equilibrium of an isothermal section for the ternary highly non-ideal system CO2+H2O+2-propanol(IPA), as described by a given model and given set of values of the model parameters. The calculation method is based on the prior identification of (univariant) key points (KPs) of the ternary isotherm. From such KPs, it is possible to build the different equilibrium lines that constitute the ternary isothermal diagram, with the help of a numerical continuation method. The results show a high level of complexity including a number of three-phase loci, critical loci, and ternary critical endpoints, together with a ternary four-phase equilibrium point. Fil: Pisoni, Gerardo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Planta Piloto de Ingeniería Química (I). Grupo Vinculado al Plapiqui - Investigación y Desarrollo en Tecnología Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina. Universidade Estadual de Maringa; Fil: Cismondi Duarte, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Planta Piloto de Ingeniería Química (I). Grupo Vinculado al Plapiqui - Investigación y Desarrollo en Tecnología Química; Argentina Fil: Zabaloy, Marcelo Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina Fil: Cardozo Filho, Lucio. Universidade Estadual de Maringa; Brasil

Liquid&ndash, liquid equilibria (LLE) characterization is a task requiring considerable work and appreciable financial resources. Notable savings in time and effort can be achieved when the experimental plans use the methods of the optimal design of experiments that maximize the information obtained. To achieve this goal, a systematic optimization formulation based on Semidefinite Programming is proposed for finding optimal experimental designs for LLE studies carried out at constant pressure and temperature. The non-random two-liquid (NRTL) model is employed to represent species equilibria in both phases. This model, combined with mass balance relationships, provides a means of computing the sensitivities of the measurements to the parameters. To design the experiment, these sensitivities are calculated for a grid of candidate experiments in which initial mixture compositions are varied. The optimal design is found by maximizing criteria based on the Fisher Information Matrix (FIM). Three optimality criteria (D-, A- and E-optimal) are exemplified. The approach is demonstrated for two ternary systems where different sets of parameters are to be estimated.

The RKPR EoS was developed in the past decade as a three-parameter model, with the intention to overcome some of the limitations of classic two-parameter cubic equations of state. More recently, parameter correlations were presented for alkanes and their mixtures, showing excellent capacity to predict the fluid phase behavior of binary mixtures up to the more asymmetric combinations and in wide ranges of temperature and pressure. In this work, different types of phase equilibrium data for multicomponent mixtures are considered, in order to see whether the good performance previously demonstrated for binary systems is also transferable to multicomponent mixtures like the ones typically encountered in synthetic fluids designed in the lab as model reservoir fluids. In the case of ternary systems with good availability of constant temperature and pressure data sets, the type and behavior of these Gibbs triangle diagrams are analyzed with reference to the general or global behavior of the system, based on pure compound saturation and binary critical lines, something we had not found in the literature preceding this work. The results and comparisons presented in this article allow concluding that RKPR2015 can be a useful tool with very good predictive capacity to describe the fluid phase equilibria of hydrocarbon mixtures. Advantages over the Peng-Robinson equation appear more clearly for the more asymmetric fluids, including synthetic gas condensates. Fil: Tassin, Natalia Giselle. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; Argentina Fil: Mascietti, Vanessa A.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Universidade Federal do Rio de Janeiro; Brasil Fil: Cismondi Duarte, Martín. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; Argentina

Ternary strategy is a promising approach to broaden the photoresponse of polymer solar cells (PSCs) by adopting combinatory photoactive blends. However, it could lead to a more complicated situation in manipulating the bulk morphology. Achieving an ideal morphology that enhances the charge transport and light absorption simultaneously is an essential avenue to promote the device performance. Herein, two polymers with different lengths of side groups (P1 is based on phenyl side group and P2 is based on biphenyl side group) are adopted in the dual‐acceptor ternary systems to evaluate the relationship between conjugated side group and crystalline behavior in the ternary system. The P1 ternary system delivers a greatly improved power conversion efficiency (PCE) of 13.06%, which could be attributed to the intense and broad photoresponse and improved charge transport originating from the improved crystallinity. Inversely, the P2 ternary device only exhibits a poor PCE of 8.97%, where the decreased device performance could mainly be ascribed to the disturbed molecular stacking of the components originating from the overlong conjugated side group. The results demonstrate a conjugated side group could greatly determine the device performance by tuning the crystallinity of components in ternary systems., Side group effect in ternary polymer solar cells is studied by adopting polymers with different side groups. With appropriate side group modification, high power conversion efficiency (PCE) over 13% is realized, which could mainly be attributed to the broadened photoresponse and optimized molecular stacking. The results demonstrate that side group plays a crucial role in determining the molecular stacking of ternary heterojunction.

In this work the usefulness of qualitatively studying and drawing three-dimensional temperature–composition diagrams for ternary systems is pointed out to understand and interpret the particular behavior of the liquid–vapour equilibrium of non-ideal ternary systems. Several examples have been used in order to highlight the interest and the possibilities of this tool, which should be an interesting support not only for lecturers, but also for researchers interested in experimental equilibrium data determination. The authors are grateful to the University of Alicante for the funding of the “Grupo de Innovación Tecnológica-Educativa (GITE) de Ingeniería Química”, where this work has been carried out.

Ternary CuO-ZrO2-Al2O3 catalysts promoted by palladium or gold were prepared and tested in CO hydrogenation reaction at 260°C under elevated pressure (4.8 MPa). The promotion effect of palladium or gold addition on the physicochemical and catalytical properties of CuO-ZrO2-Al2O3 catalysts in methanol synthesis (MS) was studied. The catalysts were characterized by BET, XRD, TPR-H2, TPD-NH3 methods. The BET results showed that the ternary system CuO-ZrO2-Al2O3 had the largest specific surface area, cumulative pore volume and average pore size in comparison with the promoted catalysts. The yield of methanol can be given through the following sequence: 5%Pd/CuO-ZrO2-Al2O3 > CuO-ZrO2-Al2O3 > 2%Au/CuO-ZrO2-Al2O3. We also found that the presence of gold or palladium on catalyst surface has strong influence on the reaction selectivity. The high selectivity of gold doped ternary catalyst is explained by the gold-oxide interface sites created on the catalyst surface and the acidity of those systems. The higher selectivity to methanol in the case of the palladium catalyst is explained by the spillover effect between Pd and CuO.

Thermodynamic description of the ternary Cu-Mg-Sn system at its Cu-Mg side is presented. The thermodynamic parameters of the binary sub-systems, Cu-Mg, Cu-Sn and Mg-Sn, are taken from the earlier SGTE-based assessments (modifying the Mg-Sn description slightly) and those of the Cu-Mg-Si system are optimized in this study using the experimental thermodynamic and phase equilibrium data. The solution phases of the systems are described with the substitutional solution model and the intermetallic Cu2Mg compound (Laves C15), treated as simple semi-stoichiometric phases of the (A,B)pCq type, is described with the twosublattice model. The present ternary description is valid for tin contents up to 45 wt% (xSn?0.30).

Prediction of bulk metallic glass (BMG) forming compositions has always been a challenge due to thermodynamic and kinetic constraints. In the present investigation, a parameter based on the enthalpy of chemical mixing (?Hchem) and the mismatch entropy (?S?/ kB) has been used to correlate with glass forming ability in some Zr based BMGs. The new thermodynamic parameter, PHS = ?H chem � ?S?/kB, is found to have strong correlation with glass forming ability in the configurational entropy (?Sconfig/R) range of 0.9-1.0. PHS has been calculated for compositions in Zr-Cu-Ag, Zr-Cu-Al, Zr-Cu-Ti and Zr-Cu-Ga ternary systems. It is observed that in all the systems studied, the best BMG composition (highest critical diameter (Zc) of glass formation) is the one that corresponds to the highest negative PHS value. Present approach using PHS could be road map to design new BMG forming compositions. � 2011 Elsevier B.V. All rights reserved.

A thermodynamic model parameter P H-S, which is a product of enthalpy of chemical mixing and mismatch entropy normalized by Boltzmann's constant, was used as a guiding tool to predict amorphous phase forming compositions in Fe-rich alloys of the Fe-Zr-B system. Attempts were made to evaluate the effect of Zr addition on the P H-S parameter and phase formation by mechanical alloying (MA) and rapid solidification processing (RSP). A systematic evaluation of the P H-S parameter of various binary compounds in the Fe-Zr-B system and ternary alloys indicated ?-7 kJ/mol as a lower bound for the formation of amorphous phase. Model predictions were verified with phase formation in two random compositions in the Fe-rich end of the Fe-Zr-B system synthesized by MA and RSP. � 2011 The Minerals, Metals & Materials Society and ASM International.

Preliminary studies on the design of lead-free solders precursors by wet chemistry methods are presented. The main objective is to assess the impact of the way of hydroxide precipitates preparation on the metal elements content of the precipitates. Namely, ternary hydroxide mixtures of three systems: a. Cu(II), Bi(III), Sn(II); b. Cu(II), Bi(III), Sb(III); and c. Cu(II), Bi(III), Zn(II) were prepared, firstly, by single-element precipitation and, secondly, by co-precipitation. Thereafter, all mixtures were reduced by using hydrogen gas. Both, the initial mixtures and the reduced samples were studied by X-ray diffraction, optical and scanning electron microscopes. The chemical compositions of the precipitates were determined experimentally and their dependence on the pH was verified. It was found that alloying occurred during the reduction procedure, but in some cases the reduction was not complete (i.e. oxide phases rest in the samples). This might be a huge obstacle to use such an approach for the preparation of lead-free solders. Moreover, the materials obtained after reductions apparently are bulk alloys, thus, the preparation of small-sized metal particles would be a challenge. Another key feature to be addressed in future studies is the correlation between the chemical compositions of the parent solution and these of the corresponding precipitates.

The results of the phase relations near ternary eutectic point in the Ag-In-Sb system are investigated in this paper. Phase equilibrium calculation was done using Thermocalc software and experimental DTA results for the chosen alloys in the isopleths with molar ration of In:Sb = 7:3; 9:1 and 1:1. The structural characteristics of these alloys have been investigated using light optic microscopy and scanning electron microscopy, while hardness measurements have also been done. Solidification path for three ternary alloys located on three different investigated isopleths was calculated using Pandat software.

(Liquid + liquid) equilibrium (LLE) data for the ternary mixtures of {water (1) + acetic acid (2) + ethyl acetate (3)} were determined at T = 298.2 K and atmospheric pressure. The concentration of each phase was determined by acidimetrictitration, the Karl Fischer technique. The reliability of the experimental data wasdetermined through the Othmer–Tobias and Hand plots. Distribution coefficients and separation factorswere evaluated over the immiscibility regions. The results show that ethyl acetate is satisfactory solvent for extraction of acetic acid from water.

International audience; Letter to the editor : The hydride CeNiInH1.8(1) has been studied by magnetization measurements. It exhibits a ferromagnetic behaviour below TC = 6.8(2) K. In other words, the insertion of hydrogen in CeNiIn induces a cerium valence transition from intermediate valence to the trivalent state.

Three's company: The first genuine ternary colloidal crystal (see picture) is composed of PbSe nanocrystals of two different diameters (blue and green) and of CdSe nanocrystals (red). Electron tomography shows that the superlattice is isostructural with the atomic lattice AIMgB4.

An extension of Barker's method to ternary systems is briefly outlined. Expressions for the standard deviations of the excess molar Gibbs free energy and the equilibrium pressure as functions of composition are obtained. These expressions are applied to accurate experimental data for the cryogenic (liquid) mixture CH3F+N2O+Xe recently measured in our laboratory. http://www.sciencedirect.com/science/article/B6TG2-3VGSGDR-4/1/e3c29abb1f0602ee677ab2a9887b8eee

This paper reports the synthesis of amorphous polymer electrolytes. Polymer-salt complexes in the ternary system were prepared by mixing two polymers, namely poly(oxyethylene) and poly(oxypropylene glycol), with sodium iodide. This three component system is represented on a ternary pseudophase diagram. The ternary compositions are completely amorphous in a certain composition range and the composition POE-12%POPG-NaI with O/Na = 10 exhibited record high conductivity of 2 x 10(-4) (Ohm cm)(-1) at ambient temperature. Formation of the amorphous electrolyte and the enhanced miscibility of the polymers were analysed using differential scanning calorimetry, X-ray diffraction and ionic conductivity studies. The cation was found to play a major role in enhancing the miscibility of the polymers.

The vanadate NaMn4(VO4)3 was obtained as darkbrown crystals as a side-product during the crystallization of the oxygen-deficient perovskite Na3MnV2O7.5 in an NaCl/KCl flux. NaMn4(VO4)3 crystallizes with the tetragonal (Mg1/2□1/2)Mg4(AsO4)3 type, space group I 4̄2d. The structure was refined from single-crystal diffractometer data: a = 7.0238(2), c = 19.8360(9) Å , R(F) = 0.013, wR(F2) = 0.033, 853 F2 values, and 49 variables. The NaMn4(VO4)3 structure is built up of different sheets stacked perpendicular to the c axis. Na, Mn and V atoms are located in dodecahedra, octahedra and tetrahedra, respectively.

International audience; Hydrogen absorption of the CeFeSi- and CeScSi-type forms of GdTiGe was performed. Before hydrogenation they show an antiferromagnetic transition at around 412 K and a ferromagnetic transition at 376 K, respectively. Hydrogenation of both forms leads to formation of the same hydride GdTiGeH which crystallizes with a filled CeScSi-type structure where all the [Gd(4)] tetrahedra are filled by hydrogen. This hydride is paramagnetic in the temperature range 4-300 K. The slightly negative value of the paramagnetic Curie temperature θ(p) confirms that all ferromagnetic interactions were destroyed in the case of the CeScSi-type form. From first-principles calculations with the PAW GGA methodology, the localization of hydrogen within the [Gd(4)] tetrahedra was confirmed through energetic stabilization. It was also seen that the energy changes significantly with volume, indicating the itinerant (delocalized) role of the electrons in the magnetism.

The diffusion profiles and the reaction paths in ternary solid solutions are determined by both thermodynamics and kinetics. The matrix of the diffusion coefficient can be described as the product of the Hessian matrix for the thermodynamic influences and the Onsager matrix for kinetic influences. In this paper the interest is focused on the influence of the ideal part of the Hessian matrix, i.e. the ideal mixing entropy on interdiffusion. The ideal diffusion profiles are calculated by a computer simulation and they are compared with experimental results from the literature. These comparisons reveal that in most cases the qualitative shape of the diffusion profiles and of the reaction paths can be considered as caused by the ideal mixing entropy. Surprisingly, the shape of the diffusion profiles turns out to depend on the component that was chosen as the so-called solvent of the ternary mixture. This means that the ideal reaction paths do not show the triangular symmetry expected for an ideal ternary system. Especially, reaction paths between starting positions showing the same concentration of one of the three components do not run along straight lines.

A thermodynamic description of the Mo-Ni-Ti system is obtained by combining results of first-principle total energy calculations with the CALPHAD approach. The enthalpies of formation of binary intermediate phases are calculated by first-principle method employing ultra-soft pseudopotentials with plane wave basis set, which are compared with the experimental data. The energy of formation of hypothetical end-members due to the sublattice model used for modeling the ternary solubility in the binary phases Ni3Ti, NiTi, and MoNi3 are also calculated by first-principle method and incorporated in the modeling of those phases. Gibbs energy parameters for equilibrium phases in the Mo-Ni-Ti system are obtained by optimization of published experimental data, by combining it with thermodynamic descriptions of the limiting binaries from the literature. The liquidus projection, isothermal and vertical sections are calculated and compared with corresponding experimental information. � 2010 Elsevier Ltd. All rights reserved.

International audience; In this work, we use an efficient and reliable "dynamic- synthetic" method for the measurement of critical properties of a variety of pure compounds, binary mixtures, and one ternary mixture. The critical phenomenon is observed via the critical opalescence in a view cell, which withstands conditions up to 543 K and 20 MPa. Excellent agreements were obtained between the measured pure compounds' properties and those listed in recent databases. Among the pure compounds measured, several refrigerants less well described in open literature (C 3F 6, C 3F 6O, R365mfc) have been compared with conventional predictive models. The critical profiles of associating, azeotropic systems ethanol + n-alkanes (C 4-C 8) are presented, as well as the critical surfaces for the ternary system n-pentane + ethanol + n-hexane. We present forms of the Cibulka and Singh's equation suitable for correlating ternary critical properties.

A simple genetic algorithm for the numerical evaluation of binodal curves in ternary systems polymer–liquid (1)–liquid (2) and polymer (1)–polymer (2)–solvent is presented. The technique exploits a specifically developed restarting technique based on a combined elitist and zooming strategy on the last population at each iteration. The objective function (fitness) is represented by the weighted sum of the squared differences of chemical potentials of the two phases of each component, obtained evaluating first derivatives of Gibbs free energy of the mixture with respect to the number of moles of the components. The method proposed (a) is numerically stable since it does not require the evaluation of first derivatives of the objective function and (b) can be applied in a wide range of cases changing the equation of state. Several comparisons with simplified iterative procedures presented in the past in the technical literature both for mixtures of two polymers with identical characteristics in a solvent and for mixtures of solvent–nonsolvent–polymer with solvent–polymer interaction parameter equal to zero are reported. Finally, a comparison between present results and the “alternating tangent approach” is reported for two technically meaningful binary systems, when a simplified PC-SAFT equation of state is adopted. The comparisons show that reliable results can be obtained by means of the algorithm proposed and suggest that the procedure presented can be used for practical purposes. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007

Reaction of anhydrous binary fluorides LiF and InF3 in sealed platinum tube at the temperature gradient 680/670°C yields α-Li3InF6. This low-temperature form crystallizes in the space group P21/m with the cell dimensions a = 4.797(3) A, b = 8.679(1) A, c = 10.366(1) A and β = 90.90(1)°. The framework is built from InF6 and LiF6 octahedra, beside [Li2F6] bitetrahedra. The b-axis seems to be the backbone in the structural features. Running along it, zigzag anionic chains $$({\rm LiF}_4 )_n^{3n - }$$ , resulting from one—edge shared [Li2F10] groups and double files of single InF6 octahedra sharing common corners with [Li2F6], create an approximately hexagonally packed framework in the plane (1 0 0). The antiferroelectric behaviour evident from dielectric studies is confirmed by the antiparallel displacements of In and Li atoms from octahedral centres. This structure is mainly featured by the disorder observed in the lightest atoms. These atoms, which exhibit two kinds of environments, have been refined as two partially occupied sites for the tetrahedral one. Within the Li3MF6 compounds (M: trivalent or 3d element), this new structure reveals unexpected structural features, inducing its ferroic properties.

Amorphous structure generated by mechanical alloying (MA) is often used as a, precursor for generating nanocomposites through controlled devitrification. The amorphous forming composition range of ternary Al-Ni-Ti system was calculated using the extended Miedema's semi-empirical model. Eleven compositions of this system showing a wide range of negative enthalpy of mixing (-Delta;Hmix) and amorphization (-?Hamor) of the constituent elements were selected for synthesis by MA. The Al 88Ni6Ti6 alloy with relatively small negative ?Hmix (-0.4 kJ/mol) and ?Hamor (-14.8 kJ/mol) became completely amorphous after 120 h of milling, which is possibly the first report of complete amorphization of an Al-based rare earth element free Al-TM-TM system (TM = transition metal) by MA. The alloys of other compositions selected had much more negative ?Hmix and Hamor but they yielded either nanocomposites of partial amorphous and crystalline structure or no amorphous phase at all in the as-milled condition, evidencing a high degree of stability of the intermetallic phases under the MA environment. Hence, the negative ?Hmix and ?Hmix amor are not so reliable for predicting the amorphization in the present system by MA. ? Indian Academy of Sciences.

Molecular dynamics simulation of binary glass 52Li2O-48P 2O5 and ternary glasses 45Li2O-42P 2O5-13LiCl and 39Li2O-36P2O 5-25LiCl was undertaken to study the effects of the addition of LiCl to the binary phosphate glass. The results show that addition of LiCl in the glass creates more non-bridging oxygens and reduces P-O-P chain lengths and branches in these chains, leading to a weakening of the glass matrix and consequent lowering of Tg. Interchain linkages mediated by Li in the binary structure diminish, and consequently better channels are created for Li+ movement, enhancing the ionic conductivity �. Structure parameters also indicate the absence of LiCl clusters in the glass matrix. ? 2004 Published by Elsevier Ltd.

In order to study equilibrium segregation, composition profiles around coherent (1 0 0) interfaces in ternary fee systems were calculated using the cluster variation method within the tetrahedron approximation. A comparison with a previous regular-solution (RS) based model was made for interfaces between two disordered phases. This RS model overestimates the maximum atomic fraction of the segregant at the interface when its bulk value is >0.1. The oscillatory decay in segregant concentration from its maximum at the interface to its bulk value is much less damped in the case of the RS model. Analysis of the damping behavior leads to a very good agreement with results from free energy expansion approximations. Finally, the CVNI calculations were extended to interfaces between ordered ternary fee phases or anti-phase boundaries. Results for the interface between the L1(2)-Cu3Au(Ag) phase and a disordered Ag-rich phase in equilibrium at 583 K, and for a non-conservative APB in the same alloy, point to a strong suppression of order near the interfaces. (C) 2003 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The title ternary compounds have been thoroughly studied by X-ray diffraction, both on powders and single crystals. The already reported GdScGe does not form exactly at the equiatomic composition but with a stoichiometry slightly richer in Gd: Gd 1.02 Sc 0.98 Ge; it crystallizes with the tetragonal CeScSi-type (ordered La 2 Sb-type, space group I4/mmm ) with a =4.261(1) and c =15.593(5) A. Gd 2.38 Sc 2.62 Ge 3 is hexagonal, Mn 5 Si 3 -type (space group P6 3 /mcm ), with cell parameters a =8.276(5) and c =6.116(6) A. Magnetic measurements show that Gd 1.02 Sc 0.98 Ge undergoes a ferromagnetic transition at T c =350 K, whilst no evidence of long range magnetic ordering has been detected for Gd 2.38 Sc 2.62 Ge 3 from 1.5 to 60 K, as deduced by preliminary heat capacity data.

The hydrogen solubility properties of solid-solution ternary Pd1-x-yDyxNiy (x = 0.020, 0.040; y = 0.0555, 0.111) alloys are investigated in the ranges 473 � T(K) � 873 and 0.05 � P(bar) � 25 respectively. From the lattice parameters of the alloys and the thermodynamic parameters of the alloy-hydrogen system, it has been found that the hydrogen solubility properties of these alloys are determined mainly by electronic effects. The relative partial molar enthalpy in the two-phase region implies that hydrogen atoms have a preference towards occupation of the interstitial sites surrounded mostly by Ni atoms.

The ternary RAgX phases, with R = Ca, Sr, Ba, Eu, Yb and X = Si, Ge, Sn, Pb, were structurally studied by means of X-ray diffraction on powders and single crystals. The tin and lead compounds exist on the equiatomic composition and crystallize in the CeCu 2 , CaLiSn and YbAgPb types. The silicon and germanium compounds are in most cases nonstoichiometric and belong to the CeCu 2 and A1B 2 types, and to three new variants of the A1B 2 structure: SrAgGe, Ba 3 Ag 2 Si 3 , Ca 5 Ag 2 Si 7 . The influence of the electron concentration factor on the stability of the different atomic arrangements is pointed out.

The ternary intermetallic compounds with general formula UTX (T = Fe, Co, Ni; X = Si, Ge) were analyzed by X-ray methods and some of their physical properties examined. All the studied phases belong to the well known TiNiSi-type structure. The compound UFeGe shows a phase transition at 500 K; at room temperature it crystallizes in a new monoclinic structure with a = 6.986, b = 4.308, c = 6.992A, β = 93.71° in the space group P21/m; above 500 K it changes into the orthorhombic TiNiSi-type. Electrical resistivity measurements were carried out in the range 1.5–300 K for all samples, and up to 600 K for UFeGe. Anomalies in the resistivity behaviour were detected for UNiSi, UFeGe, UCoGe and UNiGe at 19, 80, 46 and 41 K respectively and ascribed to magnetic transitions.

The perovskite-type compound BaPbO3 in the BaP00 system is of considerable interest in materials science and technology owing to its wide-ranging electronic and chemical applications. To determine the thermodynamic stabilities of this compound and related plumbates, the e.m.f. of the galvanic cells using both oxide and fluoride solid electrolytes and with (a) BaPbO3Ba4Pb3O10PbO, (b) Ba4Pb3O10Ba2PbO4 PbO and (c) BaPbO3Pb3O4Pb3O4BaF2 as the test electrodes have been studied over the temperature ranges 756–968 K, 797–1097 K and 695–880 K respectively. The least-squares analysis and further processing of the e.m.f data together with the standard Gibbs energies ΔGf of formation of binary oxides from the literature have yielded the expressions ΔG o f ( BaPbO 3 , s )±1.00( kJ mol −1 )= −901.56+026596T ( K ) (1) ΔG o f ( Ba 4 Pb 3 O 10 , s )±3.5( kJ mol −1 )= −3278.95+089356T ( K ) (2) and ΔG o f ( Ba 2 PbO 4 , s )±2.08( kJ mol −1 )=−1482.10+0.37421T ( K ) (3) These data together with phase equilibrium studies have been made use of in constructing the BaPbO phase diagram at 800 K.

Glass formation and electrical conductivity studies on the AgI-Ag 2 O-[ x V 2 O 5 + (1- x )P 2 O 5 ], O ⩽ x ⩽ 1, have been carried out. Glass forming region is found to be within 40 and 66.7 m/o AgI. For similar mole fraction of AgI, quaternary glasses show higher conductivities than the individual ternary systems. Glass transition temperature is found to be almost independent of the V 2 O 5 /P 2 O 5 ratio.

The thermodynamic properties and the T-x phase diagrams for liquid-solid equilibrium in II-VI and IV-VI ternary systems are described by a regular associated liquid solution model derived from that used by Jordan for ZnTe and CdTe and by the regular approximation for the solid solution. For the pseudo-binary systems exhibiting miscibility in both phases and monotonic variation of the liquidus and solidus curves, a general expression is obtained. It is independent of the interactions in the liquid, and is the same as for ideal non associated liquids. In the calculation of the ternary T-x phase diagrams five parameters are needed : the two interaction parameters α 1, α2, the two coefficients of dissociation, β 1, β2, obtained from the respective binary liquidus, and the interaction parameter W in the solid, derived from the pseudo-binary phase diagrams. Good agreement with experimental data is obtained for the pseudo-binary systems : ZnTe-CdTe, ZnTe-HgTe, ZnSe-ZnTe, CdTe-HgTe, CdTe-CdSe, HgTe-HgSe, PbSe-PbTe, PbTe-SnTe, and for the ternary systems : Zn-Cd-Te and Pb-Sn-Te. The theory is especially suited for the case β ≃ 0 and α is small. It is applied to the calculation of the chalcogen-rich part of the ternary systems : Cd-Hg-Te and Cd-Se-Te.

Different binders of Portland cement, calcium aluminate cement and calcium sulphate (PC/CAC/C $$ {\bar{\text{S}}} $$ ) have been investigated to determinate the influence the CAC and C $$ {\bar{\text{S}}} $$ amount in the reactions mechanism. Several mixtures were studied, ratios of 100, 85/15 and 75/25 of PC/CAC with 0, 3 and 5 % of C $$ {\bar{\text{S}}} $$ . Conduction calorimetric technique was used to follow the hydration during 100 h. The XRD and FTIR techniques were used as support in the analysis of the hydration products. The results have shown that the studied ternary systems form an extra amount of ettringite, and changes in the reactions mechanism with respect to a PC. The reactions mechanism depends on the CAC and C $$ {\bar{\text{S}}} $$ amount present in the different binders.