Grumman Aerospace Corporation

Northrop Grumman Systems Corporation

Albert G Tobin

The invention relates to a titanium article of manufacture having an oxidation resistant surface and a process for producing such article wherein said titanium has an aluminized surface layer formed on it by the vapor deposition of aluminum on the titanium followed by oxidizing the surface layer.

Oxidation protection method for titanium

A ductile oxidation-resistant foil is joined to a titanium alloy substrate by means of a silver-based braze alloy. The braze alloy acts as a bonding agent to join the oxidation-resistant foil to the titanium alloy substrate.

Braze bonding of oxidation-resistant foils

The present method produces a ductile oxidation-resistant surface for titanium aluminides and alloys that involves the introduction of a refractory metal diffusion barrier that is metallurgically compatible with the alloy substrate. The diffusion barrier is then coated with an intermediate copper bonding layer. The copper layer is subsequently coated with either a nickel or a nickel-based superalloy layer. If necessary, a fourth protective layer of iron-based superalloy can be used to form a protective oxide scale on exposure to a high temperature oxidizing medium. Or, the fourth layer may be nickel aluminide which forms an oxidation-resistant external layer. The advantage of this approach is that it creates oxidation-resistant surface and prevents embrittlement of the alloy substrate during high temperature oxidation exposure due to degrading coating-substrate interactions.

Barrier coatings for oxidation protection incorporating compatibility

A method is proposed to attenuate hydrogen diffusion through fusion reactor components via controlled oxidation of prealloyed surfaces. Alloys of zirconium, vanadium, titanium, niobium, tantalum, tungsten, nickel and iron may be protected from hydrogen isotope permeation by using vanadium as an intermediate layer and either chromium, nickel-chromium, silicon or aluminum as the oxide forming component. This method may also be used to prevent hydrogen embrittlement of metals from external hydrogen environments and is applicable to the majority of alloy systems exhibiting hydrogen embrittlement phenomena.

Hydrogen permeation protection for metals

Cenospheres have been formed into a closed-cell ceramic foam by the application of heat. The closed-cell ceramic foam has excellent insulating properties, is readily machinable, and has cohesive structure which makes it useful for high-temperature insulating applications such as heat shields to protect space vehicles when they re-enter the earth's atmosphere.

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Smithtown, NY, United States of America

Albert G Tobin