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Thermodynamic properties and phase equilibria for Pt-Rh alloys

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Abstract

The activity of rhodium in solid Pt-Rh alloys is measured in the temperature range from 900 to 1300 K using the solid-state cell

$$Pt - Rh,Rh + Rh_2 O_3 /(Y_2 O_3 )ZrO_2 /Pt_{1 - x} Rh_x + Rh_2 O_3 ,Pt - Rh$$

The activity of platinum and the free energy, enthalpy, and entropy of mixing are derived. Activities exhibit moderate negative deviation from Raoult’s law. The mixing properties can be represented by a pseudosubregular solution model in which excess entropy has the same type of functional dependence on composition as the enthalpy of mixing,

$$\begin{gathered} \Delta H = X_{Rh} (1 - X_{Rh} )[ - 10,970 + 45X_{Rh} ] {J \mathord{\left/ {\vphantom {J {mol}}} \right. \kern-\nulldelimiterspace} {mol}} \hfill \\ \Delta S^E = X_{Rh} (1 - X_{Rh} )[ - 3.80 + 1.55 \times 10^{ - 2} X_{Rh} ] {J \mathord{\left/ {\vphantom {J {mol}}} \right. \kern-\nulldelimiterspace} {mol}} \cdot K \hfill \\ \end{gathered} $$

The negative enthalpy of mixing obtained in this study is in qualitative agreement with predictions of semiempirical models of Miedema and co-workers and Colinet et al. The results of this study do not support the solid-state miscibility gap suggested in the literature, but are consistent with liquidus data within experimental uncertainty limits.

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References

  1. Binary Alloy Phase Diagrams, T.B. Massalski, P.R. Subramanian, H. Okamoto, and L. Kaeprzak, eds., ASM INTERNATIONAL, Materials Park, OH, 1990, vol. 3.

    Google Scholar 

  2. L. Müller: Ann. Phys., 1930, vol. 7, pp. 9–47.

    Google Scholar 

  3. J.S. Acken: J. Res. Bur. Standards, 1934, vol. 12, pp. 249–58.

    CAS  Google Scholar 

  4. P.M. Hansen: Constitution of Binary Alloys, 2nd ed., McGraw-Hill Book Co. Inc., New York, NY, 1958.

    Google Scholar 

  5. W.G. Moffatt: Handbook of Binary Phase Diagrams, Business Growth Services, General Electric Co., Schenectady, NY, 1976 and updates.

    Google Scholar 

  6. E. Raub: J. Less-Common Met., 1959, vol. 1, pp. 3–18.

    Article  CAS  Google Scholar 

  7. A.S. Darling: Platinum Met. Rev., 1961, vol. 5, pp. 58–65.

    CAS  Google Scholar 

  8. R.P. Elliott: Constitution of Binary Alloys, 1st suppl., McGraw-Hill Book Co., New York, NY, 1965, p. 748.

    Google Scholar 

  9. E. Raub and G. Falkenburg: Z. Metallkd., 1964, vol. 55, pp. 392–97.

    CAS  Google Scholar 

  10. K.T. Jacob and M.V. Sriram: Metall. Mater. Trans. A, 1994, vol. 25A, pp. 1347–57.

    CAS  Google Scholar 

  11. R.A. Rapp and F. Maak: Acta Metall., 1962, vol. 10, pp. 63–69.

    Article  CAS  Google Scholar 

  12. A.R. Miedema, P.F. de Chatel, and F.R. de Boer, Phys. B, 1980, vol. 100, pp. 1–28.

    CAS  Google Scholar 

  13. C. Colinet, A. Pasturel, and P. Hicter: CALPHAD, 1985, vol. 9, pp. 71–99.

    Article  CAS  Google Scholar 

  14. L. Pauling: The Nature of the Chemical Bond, 3rd ed., Cornell University Press, New York, NY, 1960, pp. 76–228.

    Google Scholar 

  15. O. Knacke, O. Kubaschewski, and K. Hesselmann: Thermochemical Properties of Inorganic Substances, 2nd ed., Springer-Verlag, Berlin, 1991, vols. I–II, pp. 1616–88.

    Google Scholar 

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Authors and Affiliations

  1. the Department of Metallurgy, Indian Institute of Science, 560 012, Bangalore, India

    K. T. Jacob (Professor) & Shashank Priya (Graduate Student)

  2. the Institute for Advanced Materials Processing, Tohoku University, 980-8577, Sendai, Japan

    Yoshio Waseda (Professor and Head, Research Center for Metallurgical Process Engineering)

Authors
  1. K. T. Jacob
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  2. Shashank Priya
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  3. Yoshio Waseda
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Jacob, K.T., Priya, S. & Waseda, Y. Thermodynamic properties and phase equilibria for Pt-Rh alloys. Metall Mater Trans A 29, 1545–1550 (1998). https://doi.org/10.1007/s11661-998-0076-3

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  • DOI: https://doi.org/10.1007/s11661-998-0076-3

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