The effect of niobium on the oxidation behavior of titanium in Ar/20% O{sub 2} atmospheres
The effect of niobium was studied on the isothermal oxidation of pure titanium under well-controlled environmental conditions. This material was chosen as a model system to obtain more information of the exact role of niobium on the oxidation of niobium-containing intermetallics. Several studies have already been undertaken to investigate and reveal the mechanism behind the beneficial effect of niobium on the oxidation behavior of {gamma}-TiAl-base alloys. However, due to the complexity of these systems, including often more than one reactive gas compound and alloys with more than one constituent, it is difficult or sometimes impossible to draw conclusions. In order to avoid synergistic effects (effects between different gas compounds in the gas atmospheres and material constituents), a systematic study on the isothermal oxidation of Ti-base materials, i.e., pure Ti, Ti-4(at.%)Nb, and niobium-implanted Ti, was performed. Oxidation experiments performed in dry and humidified argon/oxygen atmospheres at 800 C showed that the presence of niobium not only significantly reduced the growth of titania, but also significantly reduced the water effect, as found during oxidation of pure Ti under humidified conditions. On the other hand, because of the presence of niobium, the amount of oxygen dissolved in the underlying metallic matrix and the maximum penetration depth of oxygen in the underlying substrate was higher. In addition, the process of cracking, inducing the formation of a lamellar structure of the oxide scale, was slightly affected by the presence of niobium.
- Research Organization:
- European Commission, Ispra (IT)
- OSTI ID:
- 20050529
- Journal Information:
- Oxidation of Metals, Vol. 53, Issue 5-6; Other Information: PBD: Jun 2000; ISSN 0030-770X
- Country of Publication:
- United States
- Language:
- English
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