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Determination of Activity Coefficients of Elements and Related Thermodynamic Properties of FeSi Binary Melts Based on the Atom–Molecule Coexistence Theory
Author(s) -
Yang Xuemin,
Li Jinyan,
Li Pengcheng,
Zhang Meng,
Zhang Jian
Publication year - 2014
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201200215
Subject(s) - gibbs free energy , thermodynamics , activity coefficient , enthalpy , standard molar entropy , molar mass , chemistry , entropy of mixing , dissolution , atom (system on chip) , binary system , molecule , atmospheric temperature range , binary number , aqueous solution , organic chemistry , physics , arithmetic , mathematics , computer science , embedded system , polymer
The Raoultian activity coefficientγ Si 0of Si andγ Fe 0of Fe in the infinitely dilute solution of FeSi binary melts at temperatures of 1693, 1773, 1873, and 1973 K have been determined from the calculated mass action concentrations N i of structural units in FeSi binary melts based on the atom and molecule coexistence theory (AMCT). The activity coefficients of elements γ i relative to pure liquid matter as standard state or f %, i referred to 1 mass percentage as standard state or f H, i based on the hypothetical pure liquid matter as standard state have been obtained. The values of first‐order activity interaction coefficientϵ i iore i iorh i iof Si and Fe related with activity coefficients γ i or f %, i or f H, i of Si and Fe are also determined. The standard molar Gibbs free energy change of dissolving liquid element i (l) for forming 1 mass percentage of element i in FeSi binary melts have been deduced in a temperature range from 1693 K to 1973 K. The molar mixing thermodynamic properties, such as molar mixing Gibbs energy change/enthalpy change/entropy change of FeSi binary melts have been reliably determined in a temperature range from 1693 K to 1973 K. The excess values and excess degrees of the above–mentioned molar mixing thermodynamic properties of FeSi binary melts have been also determined based on ideal solution or regular solution as a basis, respectively. The determined molar mixing Gibbs energy change of FeSi binary melts is equal to that based on regular solution as a basis in the full composition range of FeSi binary melts in a temperature range from 1693 K to 1973 K. The partial mixing thermodynamic properties of Si and Fe are not recommended to obtain from the calculated mass action concentration N Si of Si and N Fe of Fe as well as the measured activity a R, Si of Si and a R, Fe of Fe in FeSi binary melts.