# US 2021/0340874 A1 · Damping coating with a constraint layer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0340874 A1 - Document ID: US20210340874A1 - Status: Published application - Kind: A1 - Application number: 16/865,999 - Filed: 2020-05-04 - Published: 2021-11-04 - Earliest claimed: 2020-05-04 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: James Zhang; John McConnell Delvaux - Web page: https://patentgrep.com/patent/US20210340874A1 ## CPC - F01D 5/147: {Construction, i.e. structural features, e.g. of weight-saving hollow blades (F01D5/148, F01D5/16 and F01D5/20 take precedence; blade shape F01D5/141; blades with cooling or heating channels or cavities F01D5/18; heating, heat-insulating or cooling means on blades F01D5/18)} - F01D 5/16: for counteracting blade vibration - B32B 9/041: {of metal} - F01D 5/225: {by shrouding} - F01D 5/26: Antivibration means not restricted to blade form or construction or to blade-to-blade connections {or to the use of particular materials} - F01D 5/282: {Selecting composite materials, e.g. blades with reinforcing filaments} - F01D 5/288: {Protective coatings for blades} - B32B 2307/51: Elastic - B32B 2603/00: Vanes, blades, propellers, rotors with blades - F05D 2220/32: in gas turbines - F05D 2230/90: Coating; Surface treatment - F05D 2240/307: related to the tip of a rotor blade - F05D 2260/96: Preventing, counteracting or reducing vibration or noise - F05D 2300/611: Coating - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A coating is applied to a base material. The coating comprises a viscoelastic layer; and a constraint layer; wherein the viscoelastic layer is disposed on the base material and the constraint layer is disposed on the viscoelastic layer. ## Claims ### Claim 1 A coating, the coating applied to a base material, the coating comprising: a viscoelastic layer; and a constraint layer; wherein the viscoelastic layer is disposed on the base material and the constraint layer is disposed on the viscoelastic layer. ### Claim 2 (depends on 1) A coating according to claim 1, wherein the viscoelastic layer and the constraint layer join at an interface therebetween, the viscoelastic layer and the constraint layer are coextensive and conterminous on the base material. ### Claim 3 (depends on 1) A coating according to claim 1, wherein the viscoelastic layer and the constraint layer join at an interface therebetween, the viscoelastic layer is fully bonded to the constraint layer. ### Claim 4 (depends on 1) A coating according to claim 1, wherein the viscoelastic layer and the constraint layer join at an interface therebetween, the viscoelastic layer is partially bonded to the constraint layer. ### Claim 5 (depends on 4) A coating according to claim 4, wherein defects are formed at the interface partially bonding the viscoelastic layer to the constraint layer, the defects enabling vibration and frictional interaction at the partially bonded interface between the partially bonded viscoelastic layer and the constraint layer. ### Claim 6 (depends on 5) A coating according to claim 5, wherein the defects include particles, the particles configured for vibration and frictional interaction at the partially bonded interface between the partially bonded viscoelastic layer and the constraint layer. ### Claim 7 (depends on 6) A coating according to claim 6, wherein the coating extends at least partially on the airfoil from the tip towards the base. ### Claim 8 (depends on 6) A coating according to claim 6, wherein the turbine blade includes at least one part-span shroud on the airfoil, wherein coating extends from the tip at least towards the at least one part span shroud. ### Claim 9 (depends on 8) A coating according to claim 8, wherein the at least one part-span shroud on the airfoil includes the coating. ### Claim 10 (depends on 6) A coating according to claim 6, wherein coating extends fully on the airfoil to the base. ### Claim 11 (depends on 10) A coating according to claim 10, wherein a fillet connects the airfoil to the base, and the coating is applied to the fillet and the base. ### Claim 12 (depends on 1) A coating according to claim 1, wherein the constraint layer includes a pre-sintered Preform (PSP). ### Claim 13 A turbine blade, the turbine blade comprising a base material; a coating applied to the base material, wherein the coating includes: a viscoelastic layer; and a constraint layer; wherein the viscoelastic layer is disposed on the base material and the constraint layer is disposed on the viscoelastic layer. ### Claim 14 (depends on 13) A turbine blade according to claim 13, wherein the viscoelastic layer and the constraint layer join at an interface therebetween, the viscoelastic layer and the constraint layer are coextensive and conterminous on the base material. ### Claim 15 (depends on 13) A turbine blade according to claim 13, wherein the viscoelastic layer and the constraint layer join at an interface therebetween, the viscoelastic layer is fully bonded to the constraint layer. ### Claim 16 (depends on 13) A turbine blade according to claim 13, wherein the viscoelastic layer and the constraint layer join at an interface therebetween, the viscoelastic layer is partially bonded to the constraint layer. ### Claim 17 (depends on 16) A coating according to claim 16, wherein defects are formed at the interface partially bonding the viscoelastic layer to the constraint layer, the defects enabling vibration and frictional interaction at the partially bonded interface between the partially bonded viscoelastic layer and the constraint layer. ### Claim 18 (depends on 13) A turbine blade according to claim 13, wherein the defects include particles, the particles configured for vibration and frictional interaction at the partially bonded interface between the partially bonded viscoelastic layer and the constraint layer. ### Claim 19 (depends on 13) A turbine blade according to claim 13, wherein the turbine blade includes at least one part span shroud on the airfoil, wherein coating extends from the tip at least towards to the at least one part span shroud. ### Claim 20 A gas turbine system, the gas turbine system comprising a turbine blade, the turbine blade the turbine blade defining a base material, the gas turbine system further including: a coating, wherein the coating includes: a viscoelastic layer; and a constraint layer; wherein the viscoelastic layer is disposed on the base material and the constraint layer is disposed on the viscoelastic layer, wherein the viscoelastic layer and the constraint layer join at an interface therebetween, the viscoelastic layer is partially bonded to the constraint layer; and wherein defects are formed at the interface partially bonding the viscoelastic layer to the constraint layer, the defects enabling vibration and frictional interaction at the partially bonded interface between the partially bonded viscoelastic layer and the constraint layer.