United Technologies Corporation

David S Duvall

Daniel F Paulonis

Dinesh K Gupta

William A Owczarski

Robert P Schaefer

Duane L Ruckle

William H King

Gerard Casimer Sikorowicz

Improved coating compositions are described for the protection of superalloys at elevated temperatures. The coatings of the NiCrAlY or NiCoCrAlY type are significantly improved by the use of higher levels of yttrium.

Overlay coatings with high yttrium contents

Improved coating compositions are described for the protection of superalloys at elevated temperatures. The coatings are of the MCrAlY type where M is nickel or cobalt and are significantly improved by the addition of from 0.1-7% silicon and 0.1-2% hafnium. Coatings of the invention are preferably applied by plasma spraying and as so applied are found to be substantially more effective than prior art coatings.

Overlays coating for superalloys

Plasma flame sprayed ceramic thermal barrier coatings on metal substrates are treated to make the coatings resistant to damage from thermal cycling. The coating and substrate are heated to a temperature in the range of 820.degree.-1150.degree. C. then are quenched in a medium capable of producing a surface heat flux of at least 1.3.times.10.sup.5 watts/m.sup.2. This causes creation of a fine network of cracks extending from the surface of the coating to the surface of the substrate whereby during thermal cycling, buildup of damaging stresses at the coating-substrate interface is avoided.

Quench-cracked ceramic thermal barrier coatings

Overlay coatings for superalloys

A class of age hardenable nickel base alloys for use as filler wires in fusion welding superalloys is described. The alloys contain manganese in levels of from about 0.5 to 3 percent to greatly reduce the incidence of heat-affected zone cracking in the metal being welded. The weld filler alloys also contain significant amounts of aluminum, titanium, tantalum, and columbium, and therefore the resultant welds can be age hardened to relatively high strength levels.

Age hardenable nickel superalloy welding wires containing manganese

An interlayer for transient liquid phase diffusion bonding of the nickel, cobalt and iron alloys is provided between surfaces to be joined as a thin lamellar composite.

Method of making a composite interlayer for diffusion bonding

In filling voids in or between metallic articles, as in the repair of cracks or other surface defects in castings, the void is filled with a powder mix which upon heat treatment fills the void. The filler powder mix is a blend of at least two distinct powder components and in terms of overall composition preferably corresponds to that of article being repaired. The components comprising the mix are selected to provide a transient liquid phase and isothermal resolidification of a portion of the mix at the temperature below the article melting point. A subsequent heat treatment is preferably utilized for homogenization.

Metallic filler material

Composite interlayer for diffusion bonding

Method of repairing surface defects using metallic filler material

A reduced melting point interlayer for transient liquid phase diffusion bonding of the nickel, cobalt and iron alloys is provided as a thin coating integral with one or more of the surfaces to be joined.

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Cobalt, CT, United States of America

David S Duvall