United Technologies Corporation

Howmet Corporation

Stephen Chin

David N Duhl

Norman S Bornstein

Donald R Parille

Harry E Eaton

Dilip M Shah

Philip H McCluskey

Charles A Ellis

Glenn A Cotnoir

George E Foster

Daniel R Godin

H David Harter

Ellen Y Sun

Roscoe A Pike

John G Smeggil

John J Brennan

William Patrick Allen

Harry Edwin Eaton, Jr

Michael A DeCrescente

Bart M Kilinski

Paul R Johnson

Paul R Aimone

Robert L McCormick

A bond layer for use on a silicon based substrate. The bond layer comprises an alloy comprising a refractory metal disilicide/silicon eutectic. The refractory metal disilicide is selected from the group consisting of disilicides of molybdenum, chromium, hafnium, niobium, tantalum, rhenium, titanium, tungsten, uranium, vanadium, yttrium and mixtures thereof. The refractory metal disilicide/silicon eutectic has a melting point of greater than 1300&#xb0; C.

Bond coat for silicon based substrates

Coatings containing at least 85% by volume crystalline mullite with less than 15% by volume of amorphous material and mullite dissociation phases are plasma sprayed onto the surface of a silicon based ceramic substrate by closely controlling the plasma spray parameters including the mullite feed stock and its particle size, the nozzle outlet stand-off distance, movement of the substrate past the plasma flow, back side heating of the substrate and the powder feed rate through the plasma spray gun.

Plasma sprayed mullite coatings on silicon based ceramic materials

A barrier layer for a silicon containing substrate comprises an alkaline earth aluminosilcate and an additive component capable of forming a reaction product with silica.

Substrate containing silicon and a barrier layer which functions as a protective/thermal barrier coating

Single crystal superalloy castings are described which have excellent oxidation resistance. The oxidation resistance is due to the presence of small but effective amounts of magnesium in the casting. Single crystal castings containing magnesium in the range of 5-200 parts per million, by weight, are described.

Method of making oxidation resistant single crystal superalloy castings

Oxidation resistant single crystal superalloy castings

Molybdenum disilicide base materials and methods for producing them are described. Mixtures of MoSi.sub.2 powder and other powders including SiO.sub.2, Si.sub.3 N.sub.4, SiC and Mo.sub.5 Si.sub.3 are plasma sprayed. Another embodiment which involves oxidation of MoSi.sub.2 is also disclosed. The resistant materials have particular utility as coatings for Nb alloys.

Molybdenum disilicide based materials with reduced coefficients of

Superalloy articles are made more oxidation resistant by a process which includes heat treating the article in the presence of foreign chemical species, at a temperature at which the foreign chemical species reacts with and modifies any oxide film present on the article surface. The heat treatment is best carried out at a temperature above the gamma prime solvus temperature of the article and below the incipient melting temperature of the article. Alternatively, the heat treatment may be carried out within the range defined by the incipient melting temperature of the article and about 150.degree. C. below the incipient melting temperature of the article. At such temperatures the foreign chemical species reacts with and modifies the oxide film on the article surface. Sulfur is then able to diffuse through such modified film, and a more oxidation resistant component is produced.

Method for removing sulfur from superalloy articles to improve their

The oxidation resistance of a superalloy casting such as an equiaxed, directionally solidified, or single crystal casting, is improved by melting, pouring, or casting the alloy so as to react with a magnesium or calcium-bearing ceramic material. Magnesium or calcium is introduced into the alloy through a controlled reaction between the alloy and the magnesium or calcium-bearing ceramic material.

Oxidation resistant superalloy castings

Nickel base superalloys having properties equal to or better than alloys currently used in gas turbine engines are described. Preferably, the alloys of the present invention are cast into single crystals.

High strength single crystal superalloys

Single crystal nickel base superalloys, having low chromium and cobalt contents are described. The alloys have a unique combination of aluminum, tantalum, and rhenium, which results in surprisingly good oxidation and corrosion resistance, and a melting point in excess of 2500.degree. F. The properties of the alloys of the present invention make them suitable for use as components in the high temperature section of gas turbine engines.

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Wallingford, CT, United States of America

Stephen Chin