Article Thermodynamic Relationship between Enthalpy of Mixing and Excess Entropy in Liquid Binary Alloys was published on March 1, 1993 in the journal International Journal of Materials Research (volume 84, issue 3).
The viscosities of mercury and the Hg-In system have been determined by the capillary method. In pure mercury, the so-called “pre-freezing” phenomenon, which shows a considerably larger viscosity than that expected in ordinary exponential temperature dependence near the freezing point, has been observed. The phenomenon can be explained on the basis of formation of clusters in the liquid.The viscosity measurement was also carried out on the liquid Hg-In system, which contains eutectics and intermetallic compounds. For this systems, the isothermal viscosities did not vary with composition in a linear manner. The viscosity-composition curves have inflection points at the Hg-35 at%In eutectic composition, and also have sharp maxima in ∂η⁄∂C at the Hg-50 at%In (HgIn) composition, where the compound is formed in the solid state. The data suggest that clusters presumably exist in the liquid at the composition of intermetallic compound (HgIn) and its vicinities.
By use of basic physical quantities from the practical standpoint, a trial has been made in formulating relationships in viscosity-diffusivity and viscosity-surface tension of molten metals at or near the melting point.Using the expressions, which have been drived by authors from the theoretical standpoint, the relationships in viscosity (ηm), diffusivity (Dm), and surface tension (γm) of molten metals at or near the melting point can be expressed with such basic physical quantities as atomic weight (M), melting point (Tm) and atomic volume(Vm) as follows:Dm=3.5×10-6(Tm/M)1/2Vm1/3(From the modified Stokes-Einstein.)rm/ηm=7.0×103(Tm/M)1/2rmDm=1.4×10-5Tm3/2/Vm1/3M1/2andrm/ηmDm=2.0×109Vm-1/3 ≈ 109
A statistical thermodynamic solution model based on the free volume theory is applied to liquid iron-nitrogen based ternary alloys to derive the relationship between the enthalpy interaction parameter and the entropy interaction parameter. A linear relationship between those parameters is obtained. Then, Wagner's interaction parameters of nitrogen with some metallic elements in liquid iron alloys are evaluated. These results show that the free volume of the solute elements is an important factor to determine the excess entropy terms in those alloys
In order to determine the viscosity of liquid metals by the oscillating vessel method with high accuracy, an investigation was made on the corrections for the Roscoe’s absolute equation that connects the period and the logarithmic decrement of oscillations with the viscosity of liquid.Corrections for the end effect were examined experimentally by the use of the cylindrical vessel of graphite. The values of the end correction for liquid metals such as Hg, Sn and Pb were obtained.Corrections for the slipping effect were discussed on the basis of the corrected Roscoe’s equation which was previously proposed by the authors.Furthermore, the relation between the correction factor ζ in the corrected Roscoe’s equation and the work of adhesion was also investigated experimentally.
Abstract Electromotive force measurements (EMF) of an electrochemical cell with zirconia as solid electrolyte were performed to determine the Ga activity from 973 to 1273 K in the entire compositio...
EMF of galvanic cells with stabilized zirconia solid electrolyte was measured to determine the activity of gallium in liquid Ga–In–Bi alloys in the temperature range from 1050 to 1200 K along three pseudobinary lines of (InyBi1−y)–Ga where y=0.25, 0.50 and 0.75. A mixture of Ga and Ga2O3 was used as the reference electrode. The activity curves of Ga show positive deviations from ideality in the whole composition range. Iso-activity curves at 1073 K in the ternary Ga–In–Bi alloys were derived by combining the results of this study with activity data for Ga–In and Ga–Bi alloys. The iso-activity curves display small waves, and have concave curvatures in the Ga-rich region at lower temperatures. Using Darken’s equation, data for two binary systems Ga–In and Ga–Bi, and ternary data determined in this study, ΔGXS at 1073 K was derived. The results are compared with those from the general model calculation proposed by Chou.
