United Technologies Corporation

Francis J Wallace

Norman S Bornstein

Michael A DeCrescente

Peter E Voyer

Thomas C Walsh

Michael A De Crescente

An article with an improved MCrAlY coating is disclosed wherein a plasma sprayed MCrAlY coating is provided with a metallic envelope and then hot isostatically pressed to densify the coating and interdiffuse the envelope. Thus, the substrate is provided with a coating which in its bulk is the densified plasma coating with an outer surface zone which is enriched in a metal which enhances the oxidation-corrosion protective properties of the coating. Preferred coatings have a standard CoCrAlY bulk with a metal-enriched surface zone of about 0.02 mm depth. When aluminum is added the surface zone is comprised by weight percent of about 60 Co, 20 Cr and 22 Al. With chromium the surface zone is about 50 Co, 43 Cr and 8.5 Al.

Plasma sprayed MCrAlY coating

The method of fabricating a jet engine casing into two removable halves is disclosed. The method includes turning a cylindrical blank to obtain the radial structural ribs, diametrically slotting axially the outer diameter to receive two mating flanges and boring the inside diameter to remove sufficient material to expose the inner edge of the mating flanges whereby the casing is split along the axial axis.

Method for manufacturing a split engine casing from a cylinder

The oxidation-corrosion resistance of plasma sprayed MCrAlY overlay coatings is improved. The coating method involves plasma spraying the MCrAlY coating alloy onto a superalloy substrate, applying a chromium or aluminum envelope over the outer surface of the coating or mechanically working the outer surface to seal the surface against penetration by the high pressure isostatic atmosphere to be subsequently applied and then hot isostatically pressing the coated substrate to close the coating defects and diffuse at least a portion of the envelope, if present, into the overlay coating. The invention thus can provide an MCrAlY coating not only substantially free of pores, voids and the like defects but also having at least an outer zone enriched in chromium, aluminum or like metals.

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Windsor, CT, United States of America

Francis J Wallace