Thermodynamic properties of the chromium telluride Cr2Te3

Conclusions In an investigation, based on measurements of the emf of concentration galvanic cells, determinations were made of the isobaric-isothermal potential, heat, and entropy of formation of the chromium telluride Cr₂Te₃ over the temperature range 350–450°C.Translated from Poroshkovaya Metallurgiya, No. 9 (141), pp. 45–47, September, 1974.     

Waspaloy合金碳化物和γ'相析出规律的热力学计算

利用热力学计算软件Thermo-Calc对Waspaloy合金中可能析出的平衡相以及元素含量变化对其影响进行了计算分析.结果表明:碳含量的增加可以明显地提高碳化物的析出量,但对碳化物的析出温度的影响较小;γ'的析出量和析出温度均随Al、Ti含量的增加而增加,Al的影响尤为明显;Ti是MC的主要形成元素,Ti含量的增加可以提高MC的析出量,但对其析出温度无太大影响;M₂₃C₆的析出量不受Cr含量的影响,而析出温度却随着Cr含量的增加而提高.     

粉末高温合金平衡相析出行为的热力学对比

利用热力学平衡相计算方法及相应的高温合金数据库对René95,René88DT和an741нп三种合金在平衡相析出温度范围和析出量以及之间的关联性进行了系统的热力学计算对比分析.结果表明:三种粉末高温合金的平衡相种类基本相同,主要平衡相为γ,γ'和碳化物M₂₃C₆,MC,M₆C.René95合金中的碳化物含量要高于其他两种合金.зп741нп有着较高的γ'相析出温度和较大的析出量.随温度降低,Co和Nb从γ'相中析出,在其周围富集,其中зп741нп合金中尤为明显.合金元素的偏聚度也和合金的初熔点与终熔点之差的大小有关,其熔解区间越大即初熔点和终熔点之差越大,合金元素的偏聚度越大.     

Copper-scandium system: Thermodynamic properties of intermetallics and liquid alloys

Thermodynamic simulation of the binary Cu-Sc system is performed for a wide temperature range using experimental data on the thermodynamic properties of solid Cu-Sc alloys. The results obtained are used to estimate the thermodynamic functions of mixing and the activities of the components and to determine the composition of melts using an ideal solution model for interaction products. The calculated enthalpies of mixing at 1873 K agree adequately with the experimental data obtained by calorimetry.     

Thermodynamic properties of calcium hexaboride

The temperature dependence of the heat capacity of CaB₆ in the range 20–2500 K was calculated. The calculated results were confirmed by experimental measurements in the range 198–673 K, and standard enthalpy and entropy values were calculated. A recommended standard enthalpy of formation of CaB₆ was obtained from data in the literature. Equations for the thermodynamic functions of CaB₆ in the range 298.15–2500 K were obtained, which are suitable for the thermodynamic analysis of processes involving calcium hexaboride. Institute for Materials Science Problems, Ukrainian Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 7–8, pp. 63–66, July–August, 1997.     

Thermodynamic properties of magnesium-lead alloys

Magnesium activities in liquid magnesium-lead alloys have been measured with electromotive force cells over the temperature range 745 to 868 K and over the mole fraction range 0.03 <X _Mg<0.50. The exper imental data were used to evaluate the parameters in the empirical temperature-composition relationship proposed by Krupkowski for describing the activity coefficients. Values generated from the Krupkowski formulae were utilized with data for liquidus compositions to evaluate the free energies of formation of the solid intermediate phases and compared with available experimental data for Mg₂Pb.     

Thermodynamic properties of indium oxide

Abstract

Equilibrium decomposition pressures of oxygen were established at a variety of temperatures over small lumps of In₂O₃, by continuous analysis of a hydrogen carrier gas stream for water vapour. The analysis was done by utilizing the variation of thermal conductivity of gas with changes in composition. The steady-state partial pressures developed in the carrier gas were independent of flow rate from 20 to 160 cc/min, and they agree with the equilibrium values established in previous experimental work. The equation

?G_T^o = 219,000 ? 8.648T log T ? 51.065T (± 2kcal)

is suggested for calculating the free energy of the following reaction over the temperature range 430 to 850°K:

In₂O_3(s) ? 2In_(l) + 3/2 O_2(g)

Résumé

Les pressions d'oxygène, de décomposition à l'équilibre de petits morceaux de In₂O₃, ont été établies à diverses températures, en analysant en continue la vapeur d'eau d'un gaz éluant d'hydrogène. L'analyse a été faite en se basant sur la variation de la conductivité thermique du mélange gazeux en foncdon de sa composition. Les pressions partielles, développées dans le gaz entraineur, en régime permanent, étaient indépendantes du débit, dans la gamme de 20 à 160 cc/min; elles concordent avec les valeurs d' équilibre établies lors de travaux antérieurs. L'équation

?G_T^o = 219,000 ? 8.648T log T ? 51.065T (± 2kcal)

est proposée pour calculer l'enthalpie libre de la réaction suivante, sur l'intervalle de température de 430 à 850°K:

In₂O_3(s) ? 2In_(l) + 3/2 O_2(g) .     

Thermodynamic properties of Mn-Si alloys

All available literature data on the thermodynamic properties of Mn-Si alloys are analyzed. Optimized concentration dependences of the thermodynamic functions of mixing are obtained.