Accession Number : AD0482191

Title :   OXIDATION OF NICKEL AND NICKEL-COBALT DISPERSION STRENGTHENED ALLOYS.

Descriptive Note : Technical rept.,

Corporate Author : WATERVLIET ARSENAL NY

Personal Author(s) : Saegusa, Fumihiko

Report Date : MAR 1966

Pagination or Media Count : 33

Abstract : Oxidation behavior of electrodeposited Ni-Al2O3 and Ni-Co-Al2O3 alloys has been studied in the temperature range from 800 to 1100 C. The oxidation of both alloys followed approximately a parabolic rate law with activation energies of 40.2 Kcal/mole for Ni-Al2O3 and 39.7 Kcal/mole for Ni-Co-Al2O3. It appeared that the diffusion of nickel ions controlled the kinetics of oxide formation and that the presence of the dispersed Al2O3 particles had no significant effect on the oxidation kinetics. The metallographic examination showed that the oxide scale formed on both alloys consisted of two zones. The constituents of the oxidation product were analyzed by the techniques of electron diffraction, electron microprobe analysis and electronmicrography. The inner oxide layer formed on Ni-Al2O3 was identified as NiAl2O4 and that formed on Ni-Co-Al2O3 as (Co, Ni) Al2O4. The outer layers were NiO for the nickel alloy and (Ni, Co)3O4 for the nickel-cobalt alloy.

Descriptors :   (*NICKEL ALLOYS, HIGH TEMPERATURE), (*OXIDATION, NICKEL ALLOYS), (*DISPERSION HARDENING, NICKEL ALLOYS), CORROSION, ELECTRODEPOSITION, COBALT ALLOYS, TEMPERATURE, IONS, ALUMINUM COMPOUNDS, TETROXIDES, DISTRIBUTION, ELECTRON DIFFRACTION, ELECTRON OPTICS, MICROANALYSIS, OXIDES.

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE