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Formation and Healing of Voids at the Metal-Oxide Interface in NiAl Alloys

H. Svensson ; Pavleta Knutsson (Institutionen för teknisk fysik, Mikroskopi och mikroanalys) ; Krystyna Stiller (Institutionen för teknisk fysik, Mikroskopi och mikroanalys)
Oxidation of Metals (0030-770X). Vol. 71 (2009), 3-4, p. 143-156.
[Artikel, refereegranskad vetenskaplig]

The present investigation concerns the formation and healing of voids at the metal-oxide interface in beta-NiAl alloys. It is shown that transient cavities form at the metal-oxide interface during the initial stage of isothermal oxidation at 1,050 A degrees C. These voids disappear after a few hours of oxidation, due to their filling with oxide. It is proposed that the filling of the transient voids occurs through cracks in the outer oxide scale. This allows for an oxygen transport into the cavities where a new oxide is created and grows outwards from the metal surface. Pt-containing beta-NiAl alloys that have better resistance to oxide spallation show suppressed formation of cavities and/or a faster filling of voids. This is explained by the enhanced diffusion of Al in these materials.

Nyckelord: Oxidation, Nickel aluminides, Cavities, Vacancy injection, Diffusion, Transmission electron microscopy, cyclic oxidation behavior, sulfur segregation, nickel-aluminides, cavity formation, pore formation, scales, adherence, growth, interdiffusion, alpha-al2o3

Denna post skapades 2010-02-25. Senast ändrad 2017-09-14.
CPL Pubid: 115143


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Institutioner (Chalmers)

Institutionen för teknisk fysik, Mikroskopi och mikroanalys (2005-2012)


Metallurgisk process- och produktionsteknik

Chalmers infrastruktur

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