Experimental evidence for equilibrium surface segregation in a CoPd alloy

(Note: The full text of this document is currently only available in the PDF Version )

Przemyslaw J. Godowski and Stefan M. Zuber


Abstract

The surface concentration of a polycrystalline Co-Pd(30 at%) alloy was investigated over a wide temperature range by Auger electron spectroscopy. Reversible changes of surface composition were observed at temperatures of 800-1080 K. Above 1100 K, irreversible depletion of palladium in the surface region occurred. Auger transitions of different energies were used for depth profile characterization. Variation of the palladium concentration with temperature at the surface-bulk equilibrium showed palladium segregation with a heat of segregation of Q=27 kJ mol–1.


References

  1. W. M. H. Sachtler and R. A. Van Santen, Appl. Surf. Sci., 1979, 3, 121 CrossRef CAS.
  2. P. Modrak, Prog. Surf. Sci., 1995, 49, 227 CrossRef CAS.
  3. J. Du Plessis and G. N. Van Wyk, J. Phys. Chem. Solids, 1988, 49, 1441 CrossRef CAS.
  4. M. P. Seah and C. Lea, Philos. Mag., 1975, 31, 627 Search PubMed.
  5. G. P. Schwartz, Surf. Sci., 1978, 76, 113 CrossRef CAS.
  6. J. C. Hamilton and J. M. Blakely, Surf. Sci., 1980, 91, 199 CrossRef CAS.
  7. E. E. Hajcsar, P. R. Underhill, W. W. Smeltzer and P. T. Dawson, Surf. Sci., 1987, 191, 249 CAS.
  8. J. Rudny and P. J. Godowski, Pol. J. Chem., 1987, 61, 499 CAS.
  9. M. J. Dees and V. Ponec, J. Catal., 1989, 119, 376 CAS.
  10. P. J. Godowski, Appl. Surf. Sci., 1991, 47, 333 CrossRef CAS.
  11. W. Juszczyk, Z. Karpiński, J. Pielaszek and Z. Paal, J. Catal., 1993, 143, 583 CrossRef CAS.
  12. A. R. Belambe, R. Oukaci and J. G. Goodwin Jr., J. Catal., 1997, 166, 8 CrossRef CAS.
  13. P. J. Godowski and P. Marcus, Acta Phys. Pol., A, 1995, 87, 619 Search PubMed.
  14. P. J. Godowski and S. Mróz, Thin Solid Films, 1984, 111, 129 CrossRef CAS.
  15. M. P. Seah and W. A. Dench, Surf. Interface Anal., 1979, 1, 2 CrossRef CAS.
  16. W. Palmer and K. Röll, Surf. Interface Anal., 1983, 5, 105 CrossRef.
  17. J. R. Chelikowsky, Surf. Sci., 1984, 139, L197 CrossRef CAS.
  18. A. R. Miedema, Z. Metallkol., 1978, 69, 455 Search PubMed.
  19. P. M. Ossi, Surf. Sci., 1988, 201, L519 CrossRef CAS.
Click here to see how this site uses Cookies. View our privacy policy here.