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US 9,169,740 B2Granted
Friable ceramic rotor shaft abrasive coating
AssigneeUnited Technologies Corporation
InventorsChristopher W. Strock, Paul H. Zajchowski
Life of this patent
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Abstract
An abrasive coating on a rotor shaft interacts with cantilevered vanes to form an abradable air seal in a turbine engine. The abrasive coating includes a metal bond coat, and an abrasive layer containing a plurality of abrasive CBN grit particles in a ceramic matrix.
Claims25
An abrasive coating for a rotor shaft, the abrasive coating comprising:
- a metal bond coat layer on the rotor shaft;
- and
- an abrasive layer over the bond layer for contact with vanes during operation of the rotor shaft, the abrasive coating including a plurality of cubic boron nitride (CBN) grit particles in a matrix containing hexagonal boron nitride (hBN), wherein the abrasive coating is weakened by increasing the volume fraction of hBN to weaken bonding between splats of the abrasive coating such that the matrix is configured with weakly bonded splats which are friable during use such that splats with dull CBN grit particles fall out of the matrix exposing fresh splats with sharp CBN grit particles.
An abrasive coating for a rotor shaft, the abrasive coating comprising:
- a metal bond coat layer on the rotor shaft ranging in thickness from about 3 mils to about 7 mils (76 to 178 microns);
- and
- an abrasive layer comprising splats of a CBN grit in a matrix containing hexagonal boron nitride (hBN) overlying the metal bond layer for contact with cantilevered vanes during operation of the rotor shaft to form an abradable air seal, the abrasive layer having a thickness from about 3 mils to about 7 mils (about 76 to about 178 microns), and wherein the abrasive coating is weakened by the volume fraction of hBN such that the matrix is configured with weakly bonded splats which are friable during use.
A compressor for a gas turbine engine comprising:
- a rotor having a plurality of axially spaced stages of compressor blades attached thereto and extending outward from a rotor shaft;
- a plurality of axially spaced stages of cantilevered vanes extending inward toward the rotor shaft for contact with a portion of the rotor shaft;
- and
- an abrasive coating on the portion of the rotor shaft for forming abradable air seals with the cantilevered vanes, wherein the abrasive coating includes a metal bond coat layer on the outer surface, and an abrasive layer comprising CBN grit in a matrix containing hexagonal boron nitride (hBN) over the metal bond layer, wherein the abrasive coating is weakened by the volume fraction of hBN such that the matrix is configured with weak inter-splat bonding which makes the abrasive coating friable.
1 more element
Dependencies are inferred from the claim text.