C.V. D’Alkaine * M.A.C. Berton, P.C. Tulio

Group of Electrochemistry and Polymers, DQ-UFSCar- 13565-905 São Carlos (SP), Brazil

Received 25 September 2002; accepted in revised form 13 December 2002

Abstract

On the basis of an ohmic model and a Tafel equation describing relations between current density and overpotentials in the film and at the metal/film interface, respectively, it is shown that a quantitative analysis of galvanostatic transients for the growth of passivating ultra-thin films on the so-called non-noble metals can be obtained. As an example, the growth of ZnO on Zn in a boric/borate buffer solution is considered. In this case, the values of the transfer coefficient and the exchange current density of the reaction at the metal/film interface were found to be 1.2 and 0.11 mA cm^-2, respectively. It was shown that a single, first film occurred at low current densities and two films at high ones. The ionic resistivity inside the single, first film, during the transients, has an initial constant value region followed by a final increase indicating the aging process. For this variation the evolution of the point defect concentrations is taken into account. For the variation of the ionic resistivity with the galvanostatic current density two types of behaviors were found, depending on the current density. An interpretation of these results is advanced in terms of the concentrations, mobilities and recombination rate of point defects inside the film

Keywords: passivation kinetics, ultra-thin films, galvanostatic experiments, quantitative analysis, zinc.

Texto completo disponível apenas em PDF.

Full text only in PDF format.

References

1. V. Ashworth, D. Fairhurst, J. Electrochem. Soc. 124 (1977) 506.        [ Links ]

2. P. Delahay, New Instrumental Methods in Electrochemistry, John Wiley & Sons, New York (1964).        [ Links ]

3. M.J. Dignam, D.B. Gibbs, Can. J. Chem. 48 (1970) 1242.        [ Links ]

4. D.A. Vermilyea, in Advances in Electroch. and Electroch. Eng. (Edited by P. Delahay, C.W. Tobias), Vol. 3, Chap. 4, Interscience, New York (1963).        [ Links ]

5. M.J. Dignam, inOxide and Oxide Films (Edited by J.W. Diggle and A.K. Vijh), Vol. 1, p. 91, Marcel Dekker Inc., New York (1972).        [ Links ]

6. A.T. Fromhold Jr, in Oxide and Oxide Films (Edited by J.W. Diggle, A.K. Vijh),Vol. 3, p. 1, Marcel Dekker Inc., New York (1976).        [ Links ]

7. C.J. Dell’Oca, D.L. Pulfrey, L. Young, Phys. Thin Films 6 (1971) 1.        [ Links ]

8.   F. Di Quarto, A. Di Paola, C. Sunseri, J. Electroch. Soc. 127 (1980) 1016.        [ Links ]

9.   M.J. Dignam, in Comprehensive Treatise of Electrochemistry (Edited by J.O’M. Bockris, B.E. Conway, E. Yeager, E. White), Vol. 4, p. 247, Plenum Press, New York (1981).        [ Links ]

10. T. Hurlen, Electroch. Acta 39 (1994) 2125.        [ Links ]

11. T. Hurlen, E. Gulbrandsen, Electroch. Acta 39 (1994) 2169.        [ Links ]

12. M. Metikos-Hukovic, A. Resetic, V. Gvozdic, Electroch. Acta 40 (1995) 1777.        [ Links ]

13. N. Sato, J. Electroch. Soc. 129 (1982) 255.        [ Links ]

14. C.V. D’Alkaine, L.M.M. de Souza, F.C. Nart, Corrosion Science 34 (1993) 129.        [ Links ]

15. D.E. Williams, Electroch. Acta 27 (1982) 411.        [ Links ]

16. M.H. Dean, U. Stimming, Corrosion Science 29 (1989) 199.        [ Links ]

17. J.O’M  Bockris, Corrosion Science 29 (1989) 291.        [ Links ]

18. H. Gerisher, Corrosion Science 31 (1990) 81.        [ Links ]

19. M. Bojinov, I. Kanazirskj, A. Girginov, Electroch. Acta 40 (1995) 873.        [ Links ]

20. D.E. Williams, G.A. Wright, Electroch. Acta 21 (1976) 1009.        [ Links ]

21.C.V. D’Alkaine,M.N. Boucherit, J. Electrochem. Soc. 144 (1997) 3331.        [ Links ]

22.H. Krhon, S. Rashwan, F. Back, Ber. Bunsenges. Phys. Chem. 95 (1991) 61.        [ Links ]

23. T.P. Dirkse, J. Electrochem. Soc. 125 (1978) 1591.        [ Links ]

24. J. Hendriks, A. Van Der Putten, W. Visscher, E. Barendrecht, Electroch. Acta 29 (1984) 81.        [ Links ]

25. M. Liu, G.M. Cook, N.P. Yao, J. Electrochem. Soc. 128 (1981) 1663.        [ Links ]

26. S. Szpak, C. J. Gabriel, J. Electrochem. Soc. 126 (1979) 1914.        [ Links ]

27. Y. Chang, G. Prentice, J. Electrochem. Soc. 131 (1984) 1465.        [ Links ]

28. K. Bass, P.J. Mitchell, G.D. Wilcox, J. Smith, J. Power Sources 39 (1992) 273.        [ Links ]

29. H. Kaesche, Electroch. Acta 9 (1964) 383.        [ Links ]

30. C.P. Pauli, O.A.H. Derosa, M.C. Giordano, J. Electroanal. Chem. 86 (1978) 335.        [ Links ]

31. C.P. Pauli, M.C. Giordano, H.T. Mishima, J. Electroanal. Chem. 103 (1979) 95.        [ Links ]

32. E.E. Abd El Aal, Corrosion 55 (1999) 583.        [ Links ]

33.K.J. Vetter, Electrochemical Kinetics. Theoretical and Experimental Aspects, p. 761. Academic Press, New York(1967).        [ Links ]

34. K.J. Vetter, F. Gorn, Electroch. Acta 18 (1973) 321.        [ Links ]

35.L.H. Mascaro, Ph.D. Thesis, Chemistry Program, São Carlos Federal University, São Carlos (SP), Brazil (1992).        [ Links ]

36. S. Trasatti, O.A. Petrii, Pure and Applied Chem. 63 (1991) 711.        [ Links ]

37.Y. Pleskov, Y.Y. Gurevich., Semiconductor Photoelectrochemistry, p. 349. Consultant Bureau, New York(1986).        [ Links ]

* Corresponding author. E-mail address: dalkaine@dq.ufscar.br