Metallurgical Transactions B

, Volume 21, Issue 3, pp 521–527 | Cite as

Gibbs energies of formation of intermetallic phases in the systems Pt-Mg, Pt-Ca, and Pt-Ba and some applications

  • K. T. Jacob
  • K. P. Abraham
  • S. Ramachandran
Physical Chemistry


The standard Gibbs energies of formation of platinum-rich intermetallic compounds in the systems Pt-Mg, Pt-Ca, and Pt-Ba have been measured in the temperature range of 950 to 1200 K using solid-state galvanic cells based on MgF2, CaF2, and BaF2 as solid electrolytes. The results are summarized by the following equations: ΔG° (MgPt7) = −256,100 + 16.5T (±2000) J/mol ΔG° (MgPt3) = −217,400 + 10.7T (±2000) J/mol ΔG° (CaPt5) = −297,500 + 13.0T (±5000) J/mol ΔG° (Ca2Pt7) = −551,800 + 22.3T (±5000) J/mol ΔG° (CaPt2) = −245,400 + 9.3T (±5000) J/mol ΔG° (BaPt5) = −238,700 + 8.1T (±4000) J/mol ΔG° (BaPt2) = −197,300 + 4.0T (±4000) J/mol where solid platinum and liquid alkaline earth metals are selected as the standard states. The relatively large error estimates reflect the uncertainties in the auxiliary thermodynamic data used in the calculation. Because of the strong interaction between platinum and alkaline earth metals, it is possible to reduce oxides of Group ILA metals by hydrogen at high temperature in the presence of platinum. The alkaline earth metals can be recovered from the resulting intermetallic compounds by distillation, regenerating platinum for recycling. The platinum-slag-gas equilibration technique for the study of the activities of FeO, MnO, or Cr2O3 in slags containing MgO, CaO, or BaO is feasible provided oxygen partial pressure in the gas is maintained above that corresponding to the coexistence of Fe and “FeO.”


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  1. 1.
    K. P. Abraham, M. W. Davies, J. L. Barton, and F. D. Richardson:J. Iron Steel Inst., 1960, vol. 196, p. 82.Google Scholar
  2. 2.
    B. K. D. P. Rao and D. R. Gaskell:Metall. Trans. B, 1981, vol. 12B, p. 311.Google Scholar
  3. 3.
    K. T. Jacob:Can. Metall. Q., 1981, vol. 20, p. 89.Google Scholar
  4. 4.
    A. K. Mohanty and D. A. R. Kay:Metall. Trans. B, 1975, vol. 6B, p. 159.Google Scholar
  5. 5.
    P. R. Wengert and L. Spanoudis:J. Am. Ceram. Soc, 1974, vol. 57, p. 94.CrossRefGoogle Scholar
  6. 6.
    T. N. Rezukhina and U. N. Dmitrieba:Met. Phys., 1914, vol. 52, p. 123.Google Scholar
  7. 7.
    E. M. Savitsky, V. P. Polyakova, and E. M. Khorlin:Russ. Metall. (Engl. Transi.), 1971, vol. 1, p. 107.Google Scholar
  8. 8.
    Handbook of Binary Phase Diagrams, W. G. Moffat, ed., Business Growth Services, General Electric Company, Schenectady, NY, 1976.Google Scholar
  9. 9.
    Binary Alloy Phase Diagrams, T. B. Massalski, ed., ASM, Metals Park, OH, 1986, vol. 2, p. 1536.Google Scholar
  10. 10.
    A. Palenzona:J. Less-Common Met., 1981, vol. 78, p. 49.CrossRefGoogle Scholar
  11. 11.
    M. Allibert, C. Chatillon, K. T. Jacob, and R. Lourtau:J. Am. Ceram. Soc., 1981, vol. 64, p. 307.CrossRefGoogle Scholar
  12. 12.
    L.B. Pankratz:Thermodynamic Properties of Halides, Bull. 674, U.S. Department of Interior, Bureau of Mines, Washington, DC, 1984.Google Scholar
  13. 13.
    JANAF Thermochemical Tables, M.W. Chase, ed., American Chemical Society, Washington, DC, 1985.Google Scholar
  14. 14.
    L.B. Pankratz:Thermodynamic Properties of Elements and Oxides, Bull. 672, U.S. Department of Interior, Bureau of Mines, Washington, DC, 1982.Google Scholar
  15. 15.
    W. Bronger and W. Klemm:Z. Anorg. Allg. Chem., 1962, vol. 319, p. 58.CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Material Society 1990

Authors and Affiliations

  • K. T. Jacob
    • 1
  • K. P. Abraham
    • 2
    • 3
  • S. Ramachandran
    • 4
  1. 1.Department of MetallurgyIndian Institute of ScienceBangaloreIndia
  2. 2.Regional Research LaboratoryTrivandrum
  3. 3.Research and Development Centre for Iron and SteelSteel Authority of India Ltd.RanchiIndia
  4. 4.Process Analysis Centre for Emerging TechnologiesSteel Authority of India Ltd.MadrasIndia

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