Stability of protective oxide films on Ti-base alloys

Journal Article · Sun Dec 01 04:00:00 EST 1991 · Oxidation of Metals; (United States)

DOI:https://doi.org/10.1007/BF01151593· OSTI ID:5465295

Luthra, K L ^[1]

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1. G.E. Corporate Research and Development, Schenectady, NY (United States)

Thermodynamic calculations are performed to estimate isothermal sections of Ti-Al-O, Ti-Si-O, and Ni-Al-O phase diagrams. Very small aluminum levels (<10{sup {minus}10} at.%) are needed to stabilize alumina on Ni-Al alloys. However, much higher aluminum ({approx gt}50%) and silicon ({approx gt}40%) levels are needed to stabilize alumina and silica on Ti-Al and Ti-Si alloys, respectively. These calculations suggest that the mechanism of formation of the protective oxide films of titanium-based alloys is radically different from that on nickel-based alloys. The aluminum levels needed to form a continuous film of alumina on nickel-based alloys are dominated by kinetic factors. On the other hand, thermodynamic factors appear to dominate the alloy compositions needed to form protective films of alumina and silica on titanium-based alloys. Further work is needed to evaluate any possible role of kinetic factors.

• OSTI ID: 5465295
• Journal Information: Oxidation of Metals; (United States), Journal Name: Oxidation of Metals; (United States) Vol. 36:5-6; ISSN 0030-770X; ISSN OXMEA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105* -- Metals &amp; Alloys-- Corrosion &amp; Erosion
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COATINGS
DATA
DIAGRAMS
EXPERIMENTAL DATA
INFORMATION
KINETICS
LAYERS
MINERALS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NUMERICAL DATA
OXIDATION
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHASE DIAGRAMS
PHASE STUDIES
PROTECTIVE COATINGS
REACTION KINETICS
SCALING
SILICA
SILICON ALLOYS
SILICON COMPOUNDS
SILICON OXIDES
THERMODYNAMICS
TITANIUM ALLOYS
TITANIUM BASE ALLOYS