Brazing tape or preform for microchannels in a thermal barrier coating

Abstract

A brazing tape or preform includes a layer of a brazing material, and a plurality of ceramic members affixed to the layer. The plurality of ceramic members are configured to be removable by a ceramic solvent. The plurality of ceramic members are comprised of a plurality of water-soluble ceramic members. The ceramic solvent used to remove the ceramic members is water. The brazing material is selected from the group comprising, nickel, nickel alloys, cobalt, cobalt alloys, iron, iron alloys, and combinations thereof. The ceramic members comprise, about 60% to about 70% by weight of alumina (Al2O3), about 15% to about 25% by weight of zircon (ZrSiO4) flour, about 5% to about 15% by weight of sodium hydrogen phosphate (Na2HPO4), and about 5% by weight of sugar. The brazing tape may be configured as a flexible tape, and the brazing preform may be configured as a pre-sintered preform.

Description

CROSS-REFERENCE TO RELATED PATENT APPICATIONS[0001]This application is a continuation of application Ser. No. 15 / 062,563 filed on Mar. 7, 2016, and is hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]The method, brazing tape and brazing preform described herein relates generally to thermal barrier coatings. More specifically, the method relates to forming micro channels in a thermal barrier coating with the use of a brazing tape or preform having water-soluble ceramic members.[0003]In gas turbines, air is drawn into and is compressed by a shaft-mounted rotary-type compressor. The compressed air is mixed with fuel in combustors. The mixture is burned, and the hot exhaust gases are passed through a turbine mounted on a shaft. The flow of gas turns the turbine, which turns the shaft / rotor and drives the compressor and fan (for aircraft applications). In land based applications, the turbine may drive a generator. In aircraft applications, the hot exhaust gases flow from...

AI Technical Summary

Benefits of technology

This patent describes a brazing tape or preform that includes a layer of brazing material and a plurality of ceramic members. These ceramic members can be removed by a ceramic solvent, like water. The ceramic members are made of water-soluble materials like alumina, zircon, sodium hydrogen phosphate, and sugar. The brazing material can be nickel, nickelalloys, cobalt, cobaltalloys, iron, or ironalloys. The layer can be flexible or pre-sintered. The preform may contain voids left from the ceramic members, which can create micro channels in a thermal barrier coating. The technical effect of this invention is the creation of a brazing material with improved bonding capabilities and the ability to remove ceramic members using a ceramic solvent.

Problems solved by technology

However, the maximum temperature of the turbine inlet gases is normally limited by the materials used to fabricate the components downstream of the combustors such as the vanes and the blades of the turbine.

Ceramic TBCs usually do not adhere well directly to the superalloys used as substrate materials.

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