THE OXIDATION OF IRON-NICKEL ALLOYS. III. KINETICS OF OXIDATION OF THREE COMMERCIAL ALLOYS
Three commercial iron-- nickel alloys, containing 30, 41, and 78% nickel, were oxidLzed over the range 600 to 1OOO deg C in two atmospheres, laboratory air, and a 21.7% O/sub 2/--78.3% N/sub 2/ mixture. The oxidation of these alloys follows a parabolic weight gain-time relationship during the 60-min reaction time. Replicate experiments generally showed that the precision in determining the parabolic rate constants was better in the 0/sub 2/-N/sub 2/ mixture than in laboratory air. This effect is probably the result of day-to-day variations in composition of laboratory air. Temperature dependences of the reaction rates were determined with the Arrhenius-type equation. Both the reaction rates and the apparent energies of activation of the 30-41% alloys are consistent with a rate-determining process of cation diffusion through a spinel structare Ni/sub x/ Fe/sub 3-x/0/sub 4/. It is hypothesized that the apparent enengy of activation for the 78% alloy is due to the influence of the 3.8% Mo on the physical character of the film. Anomalously high rates were observed in both atmospheres at the higher temperatures, and this is discussed with reference to "overtemperatures,'' resulting from heat generated at the surface by oxidation. (auth)
- Research Organization:
- General Electric Co., Schenectady, N.Y.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-14-001807
- OSTI ID:
- 4212761
- Journal Information:
- Journal of the Electrochemical Society (U.S.) Absorbed Electrochem. Technol., Vol. Vol: 106; Other Information: Orig. Receipt Date: 31-DEC-60
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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