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Abstract: Two binary intermetallic compounds PrNi5 and Nd2Ni17 have been tested as getters for reducing the oxygen content in a stream of pure argon. Both the intermetallics used are the Ni richest phase in the respective rare-earth (RE)-Ni phase diagrams. The gettering efficiency has been evaluated through the quantities MTGA and OPPg. The former is the minimum temperature of the getter activity, i.e., the temperature at which the gettering action becomes detectable, and OPPg is the oxygen partial pressure in the gas stream after reaction. The best MTGA values found are 242 and 287°C for PrNi5 and Nd2Ni17, respectively, with OPPg minimum values equal to 1×10−16 and 1×10−15 Pa. Though these values are produced for a relatively short time, the average OPPg values are satisfactory for practical purposes. It has been shown that the oxidation produces the rare-earth oxide (RE2O3) and Ni. The rate-determining step has been found to be the transport of oxygen in the gas phase and its transport constant has been also calculated. [Copyright &y& Elsevier]

Abstract: The scope of this work is to present and survey a complete set of thermodynamic properties of the Ni rich part of the Ni/Rare-Earth (RE) systems for the whole rare-earth series. This set of data comes entirely from the emf vs. T experimental measurements obtained from galvanic cells with CaF2 single crystal as electrolyte. In order to calculate correctly the standard enthalpy and entropy of formation of RE2Ni17 intermetallics from the raw experimental data, the evaluation of RE solubility in Ni and stoichiometry of the Ni richest phase have been performed. In the case of Pr, the Ni richest phase has been found to be Pr2Ni13, not yet reported in the Pr–Ni phase diagram, and its thermodynamic properties have been calculated. The value of the thermodynamic activity of RE coexisting between the Ni richest phase and Ni solid solution is reported along the series and related thermodynamic partial excess quantities are also given as electronic and dilatation contributions. The apparent deviations of the standard enthalpy change of intermetallic formation with Eu and Yb from the regular trend obtained in the series are explained very satisfactorily by the divalent valence status of such as elements. [Copyright &y& Elsevier]

Abstract: The thermodynamics of Bi–In–Sn lead-free solder alloys has been studied by two different experimental techniques: torsion–effusion and differential scanning calorimetry. The results show that this ternary system at fixed Bi composition, , and 565 K behaves as a non-ideal system with exothermic passing through a minimum at and . In the whole range of the quantity and at 1050 K the average value of the bismuth activity is 0.14±0.02 which implies an average activity coefficient of Bi equal to 0.70±0.01. The Bi activity in ternary alloys at 1000 K with variable and fixed ratio has been measured. The excess integral free energy change for the mixing, , has also been evaluated by making use of both the torsion–effusion experimental and literature data for Bi–Sn and Bi–In binary systems. Under these conditions, the ternary system is not a regular solution and the entropy contribution to the free energy of mixing is dominating the Gibbs energy. [Copyright &y& Elsevier]

A general treatment is performed for a complete description of the thermodynamics of galvanic cells Pt/Me″,Me″zFj/CaF2s.c./MehMe′k,MelMe′m,MexFy/Pt type working under effusion conditions where the vaporization of Me″ is considered. The treatment has been applied to three Me2Ni17/Niss,Me″zFj/CaF2s.c./MehMe′k,MelMe′m,MexFy/Pt type working under effusion conditions where the vaporization of Me″ is considered. The treatment has been applied to three Me2Ni17/Niss,MelMe′m,MexFy/Pt type working under effusion conditions where the vaporization of Me″ is considered. The treatment has been applied to three Me2Ni17/Niss type working under effusion conditions where the vaporization of Me″ is considered. The treatment has been applied to three Me2Ni17/Niss systems with Me≡ Eu, Tb, Ho and MehMe′k is the solid solution, Niss, produced by the eutectic reaction L↔Me2Ni17s+Niss. From the emf vs T experimental data, ΔfH298θ and ΔfST¯θ have been calculated. The ΔfH298θ values for Tb2Ni17(s) and Ho2Ni17(s) are, respectively, −16.76±0.06 and −18.8±0.1 kJ/mol atoms. In the same order, the ΔfST¯θ values are −1.27±0.06 and −1.81±0.09 JK−1/ mol atoms, respectively, at T=1023 and 1085 K. For Eu2Ni17(s), ΔfHT¯θ and ΔfST¯θ are, respectively, −48±4 kJ /mol atoms and 2.0±0.2 JK−1/mol atoms, both the values at T=910 K. The latter results should be considered unexpected and the reason for this is extensively discussed. [Copyright &y& Elsevier]