ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The oxidation of Nilo 48 has been studied using thermogravimetric, metallographic, and electron probe microanalysis techniques at 700 to 1000° C. After a short period of ill-defined oxidation, the parabolic law was obeyed throughout the exposure period, which varied from ∼1050 h at 713° C to 50 h at 1000° C. The activation energy for the oxidation reaction was 48±6 kcal/mole. Examination of the external scale indicated that this was single phase and, at 1000° C, its composition corresponded to NixFe3−xO4, wherex ⩽ 0.4. There were also intergranular oxidation and nickel enrichment of the alloy underlying the external scale. After oxidation for only 10 min at 1000° C, the nickel-enriched alloy zone contained 65 wt % Ni. The manganese concentration in the scale was similar to that in the alloy. The results are discussed and compared with those of other workers and it is concluded that the rate-controlling process is the diffusion of iron through the NixFe3−xO4 lattice.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00752219
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