# US 12,110,798 B1 · Blade outer air seal with machinable coating > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,110,798 B1 - Document ID: US12110798B1 - Status: Granted - Kind: B1 - Application number: 18/428,956 - Filed: 2024-01-31 - Granted: 2024-10-08 - Earliest claimed: 2024-01-31 - Assignees: Rtx Corporation - Applicants: Rtx Corporation - Inventors: Mikayla Rogers; Joseph Micucci; Daniel Rogers; Morely Sherman; Danielle Mahoney - Web page: https://patentgrep.com/patent/US12110798B1 ## CPC - F01D 11/08: for sealing space between rotor blade tips and stator (specially-shaped blade tips therefor F01D5/20) - C04B 41/009: {characterised by the material treated} - C04B 41/5024: {Silicates (C04B41/5022 takes precedence; silico-fluorides C04B41/5018)} - C04B 41/87: Ceramics - F01D 11/122: {with erodable or abradable material (blades having cutting or grinding tips F01D5/20)} - F01D 25/007: {Preventing corrosion} - C04B 2111/00982: {as construction elements for space vehicles or aeroplanes} - F01D 25/246: {Fastening of diaphragms or stator-rings} - F05D 2220/32: in gas turbines - F05D 2230/22: by sintering - F05D 2230/312: by plasma spraying - F05D 2230/90: Coating; Surface treatment - F05D 2240/11: Shroud seal segments - F05D 2260/36: by a form fit connection, e.g. by interlocking - F05D 2260/95: Preventing corrosion - F05D 2300/21: Oxide ceramics - F05D 2300/211: Silica - F05D 2300/2112: Aluminium oxides - F05D 2300/2118: Zirconium oxides - F05D 2300/2261: of silicon - F05D 2300/5024: Heat conductivity - F05D 2300/6033: Ceramic matrix composites [CMC] - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A gas turbine engine includes a compressor section, a combustor section and a turbine section for rotation on an axis. The turbine section includes at least one row of rotating turbine blades each having a radially outer tip. A blade outer air seal is positioned radially outwardly of the radially outer tip. The blade outer air seal has a central web positioned radially outwardly of the radially outer tip. The blade outer air seal has an upstream mount arm and a downstream mount arm receiving mount structure from a static structure. The static structure has sealing members engaging an upstream outer surface of the upstream mount arm at an upstream seal material and a downstream outer surface of the downstream mount arm at a downstream seal material. A method is also disclosed. ## Claims ### Claim 1 A blade outer air seal, comprising: a center web having a first surface and a second surface opposite the first surface, and first and second faces joining the first surface to the second surface; first and second mounting arms extending from the second surface, the second surface having a center portion between the first and second mounting arms and first and second side portions on either side of the center portion; and a continuous abradable coating disposed on the first surface of the center web, at least one of the first and second faces, and at least one of the first and second side portions of the second surface. ### Claim 2 (depends on 1) The blade outer air seal of claim 1, wherein the continuous abradable coating is a first continuous coating segment, wherein each of the mounting arms have an inner surface facing the center portion of the second surface and an outer surface opposite from the inner surface, and further comprising a second continuous abradable coating segment disposed on the center portion of the second surface and the inner surfaces of each of the mounting arms. ### Claim 3 (depends on 1) The blade outer air seal of claim 1, wherein the blade outer air seal comprises a ceramic matrix composite material. ### Claim 4 (depends on 1) The blade outer air seal of claim 1, wherein the blade outer air seal comprises a monolithic ceramic material. ### Claim 5 (depends on 1) The blade outer air seal of claim 1, wherein the coating comprises at least one of rare earth silicates, alkaline earth silicates, alkaline earth aluminosilicates, yttria-stabilized zirconia, alumina-stabilized zirconia, mullite, titania, chromia, silicon, silicon oxides, silicon carbides, silicon oxycarbides, barium-magnesium aluminosilicate, hafnium oxides such as hafnon, hafnium silicon oxides, alumina-stabilized zirconia, zirconium oxides such as zircon, yttrium oxides such as yttria, mullite, and combinations thereof. ### Claim 6 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 web having a radially inner surface adjacent the tip and a radially outer surface, a forward face and an axial face joining the radially inner surface and radially outer surface, first and second mounting arms extending radially outward from the radially outer surface, the radially outer surface of the web having a forward portion, and aft portion, and a center portion between the first and second mounting arms, and a continuous abradable coating disposed on the radially inner surface of the web, and at least one of the forward portion and aft portion of the radially outer surface. ### Claim 7 (depends on 6) The gas turbine engine of claim 6, wherein the continuous abradable coating is disposed on the forward portion of the radially outer surface and the forward face of the web. ### Claim 8 (depends on 6) The gas turbine engine of claim 6, wherein the continuous abradable coating is a first continuous coating segment, and further comprising a second continuous coating segment disposed on an aft surface of the first mounting arm, a forward surface of the second mounting arm, and the center portion of the radially outer surface. ### Claim 9 (depends on 6) The gas turbine engine of claim 6, wherein the blade outer air seal comprises a ceramic matrix composite material. ### Claim 10 (depends on 8) The gas turbine engine of claim 8, wherein the continuous abradable coating is disposed on the forward portion of the radially outer surface and the forward face of the web. ### Claim 11 (depends on 10) The gas turbine engine of claim 10, wherein the blade outer air seal comprises a ceramic matrix composite material. ### Claim 12 (depends on 11) The gas turbine engine of claim 11, wherein the coating comprises at least one of rare earth silicates, alkaline earth silicates, alkaline earth aluminosilicates, yttria-stabilized zirconia, alumina-stabilized zirconia, mullite, titania, chromia, silicon, silicon oxides, silicon carbides, silicon oxycarbides, barium-magnesium aluminosilicate, hafnium oxides such as hafnon, hafnium silicon oxides, alumina-stabilized zirconia, zirconium oxides such as zircon, yttrium oxides such as yttria, mullite, and combinations thereof. ### Claim 13 (depends on 6) The gas turbine engine of claim 6, wherein the coating comprises at least one of rare earth silicates, alkaline earth silicates, alkaline earth aluminosilicates, yttria-stabilized zirconia, alumina-stabilized zirconia, mullite, titania, chromia, silicon, silicon oxides, silicon carbides, silicon oxycarbides, barium-magnesium aluminosilicate, hafnium oxides such as hafnon, hafnium silicon oxides, alumina-stabilized zirconia, zirconium oxides such as zircon, yttrium oxides such as yttria, mullite, and combinations thereof. ### Claim 14 A method of coating a blade outer air seal, comprising: applying an abradable coating to a blade outer air seal, the blade outer air seal including a center web having a first surface, a second surface opposite the first surface, and first and second faces joining the first surface to the second surface, and first and second mounting arms extending from the second surface, the second surface having a center portion between the first and second mounting arms and first and second side portions on either side of the center portion, wherein the abradable coating forms a first continuous coating segment on the first surface of the center web, at least one of the first and second faces, and at least one of the first and second side portions of the second surface. ### Claim 15 (depends on 14) The method of claim 14, wherein each of the mounting arms have an inner surface facing the center portion of the second surface and an outer surface opposite from the inner surface, and further comprising a second continuous abradable coating segment disposed on the center portion of the second surface and the inner surfaces of each of the mounting arms. ### Claim 16 (depends on 15) The method of claim 15, wherein the second coating segment is applied simultaneously with the first coating segment. ### Claim 17 (depends on 1) The blade outer air seal of claim 1, wherein the blade outer air seal comprises a ceramic matrix composite material. ### Claim 18 (depends on 1) The blade outer air seal of claim 1, wherein the blade outer air seal comprises a monolithic ceramic material. ### Claim 19 (depends on 1) The blade outer air seal of claim 1, wherein the coating comprises at least one of rare earth silicates, alkaline earth silicates, alkaline earth aluminosilicates, yttria-stabilized zirconia, alumina-stabilized zirconia, mullite, titania, chromia, silicon, silicon oxides, silicon carbides, silicon oxycarbides, barium-magnesium aluminosilicate, hafnium oxides such as hafnon, hafnium silicon oxides, alumina-stabilized zirconia, zirconium oxides such as zircon, yttrium oxides such as yttria, mullite, and combinations thereof. ### Claim 20 (depends on 14) The method of claim 14, wherein the coating segment is applied by plasma spraying, slurry infiltration and sintering, or melt infiltration.