Erosion resistant coating

Patent metadata

Field	Value
Publication number	US-9777583-B2
Application number	US-201414182675-A
Country	US
Kind code	B2
Filing date	Feb 18, 2014
Priority date	Mar 12, 2013
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A platinum plus chromium coating applied to the roots and firtrees of turbine blades where the inclusion of chromium creates a single phase outer zone which minimizes diffusion paths for sulphur which can preferentially diffuse down phase boundaries and enables a chromium rich outer oxide scale to form on top of the coating.

First claim

The invention claimed is:

1. An erosion protection coating on a shank and a root of a gas turbine engine turbine blade that is (i) mounted in a root slot of a turbine disc and (ii) comprises an aerofoil, a platform, the shank, and the root, the coating having a single gamma phase outer zone that comprises:
between 25 to 60 wt % platinum;
8 and 20 wt % chromium; and
up to 7.5 wt % aluminium.

2. The erosion protection coating according to claim 1 , wherein the single phase outer zone further comprises between 20 to 40 wt % nickel.

3. The erosion protection coating according to claim 2 , wherein the single phase outer zone further comprises between 0 to 5 wt % iron.

4. The erosion protection coating according to claim 1 , wherein
the single phase outer zone is between 4 and 30 microns thick.

5. The erosion protection coating according to claim 4 , wherein
the single phase outer zone is less than 20 microns thick.

6. The erosion protection coating according to claim 4 , wherein a maximum platinum diffusion zone is no more than 40 microns thick.

7. The erosion protection coating according to claim 5 , wherein the turbine blade comprises nickel alloy.

8. An erosion protection coating on a gas turbine engine turbine blade that is mounted in a root slot of a turbine disc, the coating comprising:
platinum; and
a single gamma phase outer zone
that comprises between 8 and 30 wt % chromium and up to 7.5 wt % aluminium.

9. The erosion protection coating according to claim 8 , wherein the single phase outer zone comprises between 25 to 60 wt % platinum.

10. A method of providing a coating on a gas turbine engine nickel turbine blade, the method comprising:
applying to the blade a coating of platinum,
heat treating the blade to provide a platinum-enriched outer layer with a thickness between 5 microns and 30 microns,
diffusing chromium into the platinum to form a single gamma phase outer zone comprising up to 7.5 wt % aluminium, and
mounting the blade into a root slot of a turbine disc.

11. The method according to claim 10 , wherein
the platinum-enriched outer layer provided by the heat treatment is less than 20 microns.

12. The method according to claim 10 , wherein
the outer zone comprises between 8 and 30 wt % chromium.

Assignees

• Rolls Royce Plc

Inventors

• Leggett Andrew Jonathan

Classifications

• C23C10/10

  Chromising · CPC title

• C23C10/28

  using solids, e.g. powders, pastes · CPC title

• C23C16/06 Primary

  characterised by the deposition of metallic material · CPC title

• F05D2300/143

  Platinum group metals, i.e. Os, Ir, Pt, Ru, Rh, Pd · CPC title

• F01D5/288 Primary

  Protective coatings for blades · CPC title