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US 12,553,358 B2Granted
Porosity variation of abradable based on hardness of material
AssigneeRtx Corporation
InventorsJuan Gomez, Ryan X. Gao
Life of this patent
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Abstract
A blade outer air seal includes a center web having a radially inner face and a radially outer face, at least one mounting arm extending from the radially outer face, and a coating disposed on the radially inner face. The coating includes an environmental barrier coating layer and an abradable layer disposed on the environmental barrier layer. The abradable layer has a Mohs hardness of 3.5 to 7.5 and the porosity of the abradable layer is chosen in view of the Mohs hardness, which significantly improves the durability of the abradable layer. A gas turbine engine and a method of protecting a blade outer air seal are also disclosed.
Claims14
A blade outer air seal, comprising:
- a center web having a radially inner face and a radially outer face;
- and at least one mounting arm extending from the radially outer face, wherein the center web and at least one mounting arm are made of a ceramic matrix composite (CMC) structural material;
- and
- a coating disposed on the radially inner face, the coating comprising:
- a bond coat layer,
- an environmental barrier coating layer, and
- an abradable layer disposed on the environmental barrier layer,
- which abradable layer contains particles of an abradable material, wherein the abradable layer has:
- a Mohs hardness of 3.5 to up to less than 4.5, and a porosity of 15% to 40%,
- a Mohs hardness of 4.5 to up to less than 5.5, and a porosity of 20% to 40%,
- a Mohs hardness of 5.5 to up to less than 6.5, and a porosity of 22% to 40%, or
- a Mohs hardness of 6.5 to 7.5, and a porosity of 25% to 40%;
- wherein the abradable layer and the radially inner face of the blade outer air seal have a difference in coefficient of thermal expansion (CTE) that is less than 50 percent based on the CTE of the CMC structural material.
10 more elements
A gas turbine engine, comprising:
- a turbine section arranged along a central engine axis, the turbine section having a turbine with at least one blade rotatable around the central engine axis, the at least one blade having a tip;
- and
- at least one blade outer air seal arranged radially outward from the tip and attached to an engine static structure, the blade outer air seal including:
- a center web having a radially inner face and a radially outer face and at least one mounting arm extending from the radially outer face, wherein the center web and at least one mounting arm are made of a ceramic matrix composite (CMC) structural material;
- and
- a coating disposed on the radially inner face, the coating comprising:
- a bond coat layer,
- an environmental barrier coating layer, and
- an abradable layer disposed on the environmental barrier layer, which abradable layer contains particles of an abradable material,
- wherein the abradable layer has:
- a Mohs hardness of 3.5 to up to less than 4.5, and a porosity of 15% to 40%,
- a Mohs hardness of 4.5 to up to less than 5.5, and a porosity of 20% to 40%,
- a Mohs hardness of 5.5 to up to less than 6.5, and a porosity of 22% to 40%, or
- a Mohs hardness of 6.5 to 7.5, and a porosity of 25% to 40%;
- wherein the abradable layer and the radially inner face of the blade outer air seal have a difference in coefficient of thermal expansion (CTE) that is less than 50 percent based on the CTE of the CMC structural material.
12 more elements
A method of protecting a blade outer air seal, comprising:
- applying a coating on a radially inner face of the blade outer air seal wherein the blade outer air seal is made of a ceramic matrix composite (CMC) structural material, the coating comprising
- a bond coat layer,
- an environmental barrier coating layer, and
- an abradable layer disposed on the environmental barrier layer, which abradable layer contains particles of an abradable material, wherein the abradable layer has:
- a Mohs hardness of 3.5 to up to less than 4.5, and a porosity of 15% to 40%,
- a Mohs hardness of 4.5 to up to less than 5.5, and a porosity of 20% to 40%,
- a Mohs hardness of 5.5 to up to less than 6.5, and a porosity of 22% to 40%, or
- a Mohs hardness of 6.5 to 7.5, and a porosity of 25% to 40%
- wherein the abradable layer and the radially inner face of the blade outer air seal have a difference in coefficient of thermal expansion (CTE) that is less than 50 percent based on the CTE of the CMC structural material.
6 more elements
Dependencies are inferred from the claim text.