General Electric Company

Norman R Lindblad

Jon Conrad Schaeffer

Mark Alan Rosenzweig

Wendy Howard Murphy

John Herbert Wood

David A Shores

Robert William Bruce

David John Wortman

A coated article is prepared by furnishing an article substrate having a free sulfur content of less than about 1 part per million. The low-sulfur article may be made of a material selected to have a low sulfur content, provided with a scavenging element that reacts with free sulfur to produce a sulfur compound, or desulfurized by contact with a reducing gas such as hydrogen. A platinum-group metal layer is deposited over the article substrate, and a ceramic coating is applied over the platinum-group metal layer.

Low-sulfur article coated with a platinum-group metal and a ceramic layer, and its preparation

A method for promoting the environmental resistance of nickel, iron and cobalt-base superalloys of the type alloyed to develop a protective oxide scale. The method entails a technique for removing sulfur during or subsequent to the casting operation. The method generally includes casting a superalloy article in a mold cavity, and then heat treating the article while surfaces of the article are in contact with a compound containing a sulfide and/or oxysulfide-forming element, such as yttria, calcium oxide, magnesia, scandia, ceria, hafnia, zirconia, titania, lanthana, alumina and/or silica. The heat treatment is performed at a temperature sufficient to cause sulfur within the superalloy article to segregate to the surfaces of the article and react with the sulfide-forming element, thereby forming sulfides at the interface with the compound. The compound is then removed from the surfaces of the article so as to simultaneously remove the sulfides and any elemental sulfur that have segregated to the surface of the article.

Method of improving environmental resistance of investment cast superalloy articles

Method for producing large tear-free and crack-free nickel base superalloy gas turbine buckets

The localized pitting tendency of castable nickel-base superalloys in a high-temperature corrosive environment is suppressed without loss of desirable hot corrosion resistance, mechanical properties or microstructural stability characteristics by displacement of molybdenum and tungsten in the carbide phase to the matrix through the addition to the alloy of a comparatively small amount of tantalum, columbium or hafnium.

Cast nickel-base alloy

A method and apparatus for forming a multilayer thermal barrier coating such that the coating is composed of substantially homogeneous layers of different ceramic materials. The method entails supporting an article within a coating apparatus and in proximity to ceramic ingots of the different ceramic materials, and then simultaneously directing electron beams at both ingots so as to maintain a portion of each ingot in a molten state. According to a particular aspect of this invention, vapors of both ceramic materials coexist within the coating apparatus, yet each ceramic material is sequentially deposited onto the article by sequentially interrupting exposure of surfaces of the article to the vapors, such that the vapors form homogeneous successive layers on the surface. Exposure of the article to one or more of the vapors can be interrupted with a baffle, such that the vapor of only one of the ceramic ingots is directly deposited on a given surface of the article at any instant. The baffle can be employed in conjunction with the article being rotated at a constant or variable speed, and/or being translated above the members within the vessel to alter the relative thicknesses of the ceramic and an intermediate layer that is formed between adjacent layers and is composed of a mixture of the ceramic materials.

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Cincinnati, OH, United States of America

Norman R Lindblad