# US 10,119,407 B2 · Tapered thermal barrier coating on convex and concave trailing edge surfaces

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- Number: US 10,119,407 B2
- Document ID: US10119407B2
- Status: Granted
- Kind: B2
- Application number: 14/767,699
- Filed: 2013-12-30
- Published: 2015-12-24
- Granted: 2018-11-06
- Earliest claimed: 2013-02-18
- Assignees: United Technologies Corporation
- Applicants: United Technologies Corporation
- Inventors: Jeffrey R Levine
- Web page: https://patentgrep.com/patent/US10119407B2

## CPC

- F01D 5/288: {Protective coatings for blades}
- F01D 5/185: {Liquid cooling (F01D5/181 takes precedence)}
- F01D 5/187: {Convection cooling}
- F01D 9/02: Nozzles; Nozzle boxes; Stator blades; Guide conduits {, e.g. individual nozzles (nozzle boxes F01D9/047)}
- F01D 25/12: Cooling
- F05D 2220/30: in turbines
- F05D 2230/312: by plasma spraying
- F05D 2230/313: by physical vapour deposition
- F05D 2230/90: Coating; Surface treatment
- F05D 2260/231: Preventing heat transfer
- F05D 2300/21: Oxide ceramics
- Y10T 29/49343: Passage contains tubular insert
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A turbine engine component has an airfoil portion having a pressure side, a suction side, and a trailing edge. The trailing edge has a center discharge cooling circuit, which center discharge cooling circuit has an exit defined by a concave surface on the pressure side of the airfoil portion and a convex surface on the suction side of the airfoil portion. The airfoil portion has a thermal barrier coating on the pressure side and the suction side. The thermal barrier coating on the convex surface tapers to zero in thickness at a point spaced from the trailing edge so as to leave an uncoated portion on the convex surface.

## Claims

### Claim 1

A turbine engine component comprising:
an airfoil portion having a pressure side, a suction side, and a trailing edge;
said trailing edge having a center discharge cooling circuit;
said center discharge cooling circuit having an exit defined by a first surface on the pressure side of said airfoil portion and a second surface on the suction side of said airfoil portion;
said airfoil portion having a thermal barrier coating on said pressure side and said suction side;
said thermal barrier coating on said second surface tapering to zero in thickness at a point spaced from said trailing edge so as to leave an uncoated portion on said second surface; and
said thermal barrier coating on said first surface tapering towards said trailing edge, wherein said thermal barrier coating on said first surface has a first thickness at a point remote from said trailing edge and a second thickness which is as much as 70% less than the first thickness at said trailing edge.

### Claim 2 (depends on 1)

The turbine engine component according to claim 1, further comprising said airfoil portion having a chord and said uncoated portion extending a distance of up to 25% of said chord.

### Claim 3 (depends on 1)

The turbine engine component according to claim 1, wherein said component is a turbine blade.

### Claim 4 (depends on 1)

The turbine engine component according to claim 1, wherein said cooling circuit is connected at one end to a source of cooling fluid.

### Claim 5 (depends on 1)

The turbine engine component according to claim 1, wherein said first surface is a concave surface and said second surface is a convex surface.

### Claim 6

A process for forming a thermal barrier coating on a turbine engine component comprising the steps of:
forming a turbine engine component having an airfoil portion and a central discharge cooling circuit in a trailing edge of said airfoil portion having an exit defined by a first surface on a pressure side of said airfoil portion and a second surface on a suction side of said airfoil portion;
forming said thermal barrier coating on said pressure side and said suction side of said airfoil portion;
said forming step comprising forming said thermal barrier coating on said second surface tapering to zero in thickness at a point spaced from said trailing edge so as to leave an uncoated portion on said second surface, and
said forming step further comprises tapering said thermal barrier coating on said first surface towards said trailing edge, wherein said step of tapering said thermal barrier coating on said first surface comprises tapering said thermal barrier coating so as to have a first thickness at a point remote from said trailing edge and a second thickness which is as much as 70% less than the first thickness at said trailing edge.

### Claim 7 (depends on 6)

The process of claim 6, further comprising said airfoil portion having a chord and forming said uncoated portion to have an extent which is up to 25% of said chord.

### Claim 8 (depends on 6)

The process of claim 6, further comprising forming said first surface as a concave surface and said second surface as a convex surface.