ISSN:
1573-4889
Keywords:
Ni3Al
;
θ-Al2O3
;
α-Al2O3
;
oxidation mechanism
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The high-temperature oxidation behaviour of pure Ni3Al alloys in air was studied above 1000°C. In isothermal oxidation tests between 1000 and 1200°C, Ni3Al showed parabolic oxidation behavior and displayed excellent oxidation resistance. In cyclic oxidation tests between 1000 and 1300°C, Ni3Al exhibited excellent oxidation resistance between 1000 and 1200°C, but drastic spalling of oxide scales was observed at 1300°C. When Ni3Al was oxidized at 1000°C, Al2O3 was present as θ-Al2O3 in a whisker form. But, at 1100°C the gradual transformation of initially formed metastable θ-Al2O3 to stable α-Al2O3 was observed after oxidation for about 20 hr. After oxidation at 1200°C for long times, the formation of a thick columnar-grain layer of α-Al2O3 was observed beneath a thin and fine-grain outer layer of α-Al3O3. The oxidation mechanism of pure Ni3Al is described.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01046884
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