Papers by Keyword: Heat of Mixing

Abstract: The FeSi system is a compound forming alloy which exhibits the interesting behavior with respect to the composition. In present work, the thermophysical properties of FeSimelts at 1873 K have been explored on using four-parameter model which is based on Maclaurin infinite series. The analytical expressions for various thermodynamic and microscopic functions have been deduced using the standard thermodynamic relations. The model parameters are estimated using experimental data of activity coefficients and excess free energy of mixing for FeSi melts at 1873 K. For theoretical calculations of the thermophysical properties of FeSi liquid alloys at 1873 K, the same values of the model parameters are used in order to maintain the consistency. The composition dependence of theoretical data for Gibbs free energy of mixing and thermodynamic activities are in excellent agreement with the corresponding experimental data at 1873 K. On using the temperature dependence of model parameters, the enthalpy of mixing and entropy of mixing of FeSi molten alloys at 1873 K arecomputed. There is a well agreement between the theory and experiment. The theoretical values of concentration-concentration structural factor, known as concentration fluctuations in the long wavelength limit agree well with experimental data for FeSi system in molten state at 1873 K. The microscopic function such as short-range order parameter has also been computed as a function of concentration of FeSi melts at 1873 K. Again, the surface properties such as surface concentration and surface tension of FeSi molten alloys at the temperatures at 1823 K and 1873 Kare analyzed by Butler modelin the framework of four-parameter model. The theoretical values are compared with the data available in the literature at 1823 K which show well agreement. Again, the excess free energy of mixing, heat of mixing, concentration fluctuations and short-range order parameter are explored at 1823 K, 1873 K, 1923 K and 2073 K. Further, the transport properties like diffusivity ratio and viscosity of FeSi liquid alloys at 1823 K, 1873 K, 1923 K and 2073 Kare computed. For this, a simple statisticalmechanical modeli.eMoelwyn-Hughes model isemployed in the framework of four-parameter model. The theoretical data exhibit the qualitative agreement with the data available in the literature. The present study reveals that FeSi melt is an ordered system in the temperature range 1823-2073 K. The model parameters are temperature dependent. The concentration dependence of short-range order parameter and diffusivity ratio indicates that there is a likelihood of the existence of complex in FeSi liquid alloys. Keywords:Free energy of mixing; heat of mixing; concentration fluctuations; short-range order parameter, surface tension; viscosity

Abstract: The thermodynamic properties like heat of mixing (ΔE), entropy of mixing (ΔS) and volume of mixing (ΔΩ) of Fe-Co liquid binary alloys are computed using our newly constructed parameter free model potential. We have also attempted to investigate the effect of various forms of exchange and correlation functions, namely, Hartree (H) and Taylor (T) on the thermodynamic properties of Fe-Co liquid binary alloys. It is found that the proper choice of the model potential along with the local field correction function play an important role in investigating the thermodynamic properties of Fe-Co liquid binary alloys.

Abstract: The aim of this paper is to review all the existing literature models on the concentration dependence of the viscosity of binary liquid alloys and to check them against the measured viscosity values in the binary liquid Cu-Ag system at 1373K.