The air oxidation of a nanocrystalline Cu-10 wt%Ni alloy at 800 degrees C

Citation
Y. Niu et al., The air oxidation of a nanocrystalline Cu-10 wt%Ni alloy at 800 degrees C, CORROS SCI, 42(10), 2000, pp. 1763-1777
Citations number
62
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Material Science & Engineering
Journal title
CORROSION SCIENCE
ISSN journal
0010-938X → ACNP
Volume
42
Issue
10
Year of publication
2000
Pages
1763 - 1777
Database
ISI
SICI code
0010-938X(200010)42:10<1763:TAOOAN>2.0.ZU;2-P
Abstract
The air oxidation of two copper-base Cu-Ni alloys having the same overall c omposition, but prepared by different methods and presenting widely differe nt grain sizes, has been carried out at 800 degrees C to examine the effect of a large reduction in the grain size on the oxidation behavior of a soli d-solution alloy. Both alloys formed an external scale of copper oxide (CuO +Cu2O) plus a region of internal oxidation of nickel. However, the overall oxidation rate of the alloy with a grain size in the nanometer range was fa ster and the depth of internal oxidation was larger than those measured for the conventional alloy under the same conditions. Moreover, the particles of nickel oxide (NiO) formed by internal oxidation were present only in the alloy-consumption region for the conventional alloy, while for the mechani cal alloy they were distributed throughout the whole thickness of the exter nal scale. These differences were attributed to a faster transport of oxyge n in the alloy and of oxygen and copper in the scales for the fine-grained material resulting from a decrease of the grain size both in the alloy and in the scale and from a concomitant increase in the effective diffusion coe fficients of the relevant species. (C) 2000 Elsevier Science Ltd, All right s reserved.