Cu-2 wt.%Ni and Cu-5wt.%Ni were oxidized at 800to 1050°C and oxygen pressures from from 5 ×10-4 to 1 atm. The oxidation, as measured bythermogravimetry, was approximately parabolic. The oxidescales could be divided in two main regions: An outerregion consisting of copper oxides and an inner porousregion, which consists of Cu2O with dispersedNiO particles. NiO particles exists as internal-oxide particles. The interface between the two layersreflects the original surface, which shows that theouter part grows by outward Cu diffusion via vacancies.The inner part grows by outward diffusion of copper and inward transport of gaseous oxygen by thedissociative-transport mechanism. The amount ofporosity, the relative thickness of the inner layercompared to the total thickness of the scale, and theoxidation rate as a function of Ni content was dependenton the reaction conditions.
Unable to display preview. Download preview PDF.
- 1.R. Haugsrud and P. Kofstad, in Proc. 4th Int. Symp. on High Temperature Corrosion and Protection of Materials, to be published.Google Scholar
- 2.J. A. Sartell and C. H. Li, Trans. Amer. Soc. Metall. 55, 158 (1962).Google Scholar
- 3.D. P. Whittle and G. C. Wood, Corros. Sci. 8, 289 (1968).Google Scholar
- 4.P. Kofstad, High Temperature Corrosion (Elsevier Applied Science, New York, 1988).Google Scholar
- 5.S. Mrowec, A. Stoklosa, and K. Godlewski, Crystal Lattice Defects 5, 239 (1974).Google Scholar
- 6.F. Perinet, S. Barbezat, and C. Monty, J. Phys. Colloq. C6, 315 (1980).Google Scholar
- 7.A. Atkinson and R. I. Taylor, Philos. Mag. A39, 581 (1979).Google Scholar
- 8.C. Dubois, C. Monty, and J. Philibert, Philos. Mag. A46, 581 (1982).Google Scholar
- 9.O. Kubashewski, E. L. L. Evans, and C. B. Alcock, Metallurgical Thermochemistry (Pergamon Press, New York, 1967).Google Scholar
- 10.K. Holte and P. Kofstad, Corros. Sci. 20, 919 (1979).Google Scholar
- 11.D. P. Whittle and G. C. Wood, J. Inst. Met. 96, 115 (1968).Google Scholar
- 12.C. Wagner and H. Hammen, Z. Phys. Chem. B40, 197 (1938).Google Scholar
- 13.T. Bretheau, C. Marhic, M. Spendel, and J. Castaing, Philos. Mag. A35, 1473 (1977).Google Scholar