Abstract
The oxidation of two Ni−Nb alloys containing 15 and 30 wt.% Nb has been studied at 600–800° C in H2−CO2 mixtures providing an oxygen pressure of 10−24 atm at 600° C and 10−20 atm O2 at 700 and 800° C, these pressures being less than the dissociation pressure of nickel oxide. The scales formed on both alloys at 600 and 700° C show only a region of internal oxidation composed of a mixture of alpha nickel and niobium oxides (Nb2O5 or/and NbO2), which formed from both the metal phases present, i.e., Ni8Nb and Ni3Nb. Only small, or even no, Nb depletion was observed in the alloys close to the interface with the zone of internal oxidation at these temperatures. On the contrary, samples of both alloys corroded at 800° C produced a continuous external scale of niobium oxides without internal oxidation. The corrosion mechanism of these alloys is examined with special reference to the effect of the low solubility of niobium in nickel.
Similar content being viewed by others
References
R. C. Svedberg, inProperties of High Temperature Alloys, Z. A. Foroulis and F. S. Pettit (eds.) (The Electrochemical Society, Princeton, NJ, 1977), p. 331.
M. F. Chen, D. L. Douglass, and F. Gesmundo,Oxid. Met. 31, 237 (1989).
Y. Niu, F. Viani, and F. Gesmundo,Corros. Sci. 36, 883 (1994).
Y. R. He, D. L. Douglass, and F. Gesmundo,Oxid. Met. 37, 217 (1992).
Y. Niu, F. Gesmundo, and F. Viani,Corros. Sci. 37, 169 (1995).
A. Perkins, inHigh Temperature Corrosion, R. A. Rapp (ed.) (NACE, Houston, 1983), p. 345.
K. Natesan,Corrosion 41, 646 (1985).
F. Gesmundo, D. J. Young, and S. K. Roy,High Temp. Mater. Process. 8, 149 (1989).
J. Stringer, inHigh Temperature Oxidation and Sulfidation Processes, J. D. Embury (ed.) (Pergamon Press, New York, 1990), p. 257.
F. Gesmundo, inHigh Temperature Materials for Power Engineering 1990 (Vol. I), E. Bachelet (ed.) (Kluwer, Dordrecht, 1990), p. 67.
T. B. Massalski, J. L. Murry, L. H. Bennett, and H. Baker (eds.),Binary Alloy Phase Diagrams (ASM, Materials Park, OH, 1986).
F. Gesmundo, Y. Niu, F. Viani, and F. Rizzo,Oxid. Met. (To appear).
C. Lupis,Chemical Thermodynamics of Materials (North-Holland, New York, 1983), Chap. VII.
R. S. Roth, J. R. Dennis, and H. F. McMurdie,Phase Diagrams for Ceramists (Vol. VI), (The American Ceramic Society, Westerville, OH, 1987), p. 130.
O. Kubaschewski,High Temp.-High Press. 4, 1 (1972).
R. A. Rapp,Corrosion 21, 382 (1965).
F. Gesmundo, Y. Niu, and F. Viani,Oxid. Met. 43, 379 (1995).
F. Gesmundo, F. Viani, and Y. Niu,Oxid. Met. 42, 409 (1995).
F. Gesmundoet al., Oxid. Met. (To appear).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Oliveira, J.F., Niu, Y., Rizzo, F.C. et al. The oxidation of Ni-Nb alloys at low-oxygen pressures at 600–800°C. Oxid Met 44, 399–415 (1995). https://doi.org/10.1007/BF01058244
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01058244