# US 2019/0169730 A1 · Methods of forming a porous thermal barrier coating > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0169730 A1 - Document ID: US20190169730A1 - Status: Published application - Kind: A1 - Application number: 15/830,062 - Filed: 2017-12-04 - Published: 2019-06-06 - Earliest claimed: 2017-12-04 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Theodore Robert Grossman; Joshua Lee Margolies - Web page: https://patentgrep.com/patent/US20190169730A1 ## CPC - C23C 4/134: Plasma spraying - C23C 4/02: Pretreatment of the material to be coated, e.g. for coating on selected surface areas - C23C 4/11: Oxides - C23C 4/18: After-treatment - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) ## Abstract A method for controlling the porosity parameter of porous thermal barrier coatings is presented. The method includes disposing a feedstock material on a substrate to form a porous thermal barrier coating. The feedstock material includes a gas-forming additive and a thermal barrier coating material. The disposing step further includes controlling the porosity parameter of the porous thermal barrier coating by controlling a feedstock material feed rate, an amount of the gas-forming additive in the feedstock material, a temperature of the disposed feedstock material on the substrate, or combinations thereof. ## Claims ### Claim 1 A method of forming a porous thermal barrier coating, comprising: disposing a feedstock material on a substrate to form the porous thermal barrier coating, wherein the feedstock material comprises a gas-forming additive and a thermal barrier coating material, and wherein the disposing comprises controlling a porosity parameter of the porous thermal barrier coating by controlling a feedstock material feed rate, an amount of the gas-forming additive in the feedstock material, a temperature of the disposed feedstock material on the substrate, or combinations thereof. ### Claim 2 (depends on 1) The method according to claim 1, wherein the controlling the porosity parameter of the porous thermal barrier coating comprises controlling the temperature of the disposed feedstock material on the substrate using an auxiliary heat source. ### Claim 3 (depends on 1) The method according to claim 1, wherein the disposed feedstock material on the substrate is heated to a temperature greater than a temperature that the substrate can withstand. Amend to claim 1 and include. ### Claim 4 (depends on 3) The method according to claim 3, wherein the disposed feedstock material on the substrate is heated to a temperature in a range from about 1000° C. to about 1500° C. ### Claim 5 (depends on 1) The method according to claim 1, wherein the controlling the porosity parameter of the porous thermal barrier coating comprises controlling the amount of the gas-forming additive in the feedstock material in a range from about 0.1 wt % to about 10 wt %. ### Claim 6 (depends on 1) The method according to claim 1, wherein the controlling the porosity parameter of the porous thermal barrier coating comprises controlling the feedstock material feed rate in a range from about 2.5 gm/min to about 100 gm/min. ### Claim 7 (depends on 1) The method according to claim 1, wherein the gas-forming additive comprises graphite, carbides, oxycarbides, nitrides, or combinations thereof. ### Claim 8 (depends on 1) The method according to claim 1, wherein the gas-forming additive comprises elemental carbon. ### Claim 9 (depends on 1) The method according to claim 1, wherein the thermal barrier coating material comprises yttria-stabilized zirconia. ### Claim 10 (depends on 1) The method according to claim 1, wherein the feedstock material is disposed on the substrate using an air plasma spray process. ### Claim 11 (depends on 1) The method according to claim 1, wherein the porosity parameter comprises an average pore size, an average pore volume, a pore size distribution, a pore microstructure, or combinations thereof. ### Claim 12 (depends on 1) The method according to claim 1, wherein the porous thermal barrier coating comprises a plurality of pores such that at least some pores of the plurality of pores are intragranular. ### Claim 13 (depends on 1) The method according to claim 1, wherein the controlling the porosity parameter of the porous thermal barrier coating comprises controlling an average pore size of a plurality of pores in the porous thermal barrier coating in a range from about 0.1 microns to about 25 microns. ### Claim 14 (depends on 1) The method according to claim 1, wherein the controlling the porosity parameter of the porous thermal barrier coating comprises controlling an average pore volume of a plurality of pores in the porous thermal barrier coating in a range from about 5 volume % to about 10 volume %. ### Claim 15 (depends on 1) The method according to claim 1, wherein the controlling the porosity parameter of the thermal barrier coating further comprises forming a graded porosity across a thickness of the thermal barrier coating. ### Claim 16 A method of forming a porous thermal barrier coating, comprising: disposing a feedstock material using an air plasma spray process on a substrate to form the porous thermal barrier coating, wherein the feedstock material comprises a gas-forming additive and a thermal barrier coating material, and wherein the disposing comprises controlling a porosity parameter of the porous thermal barrier coating by controlling a temperature of the disposed feedstock material on the substrate using an auxiliary heat source. ### Claim 17 (depends on 16) The method according to claim 16, wherein the disposed feedstock material on the substrate is heated to a temperature in a range from about 1000° C. to about 1500° C. ### Claim 18 (depends on 16) The method according to claim 16, wherein the gas-forming additive comprises elemental carbon. ### Claim 19 (depends on 16) The method according to claim 16, wherein the thermal barrier coating material comprises yttria-stabilized zirconia. ### Claim 20 A method of forming a porous thermal barrier coating comprising a graded porosity, the method comprising: disposing a feedstock material on a substrate to form the porous thermal barrier coating, wherein the feedstock material comprises a gas-forming additive and a thermal barrier coating material, and wherein the disposing comprises forming the graded porosity in the thermal barrier coating by controlling: an amount of the gas-forming additive in the feedstock material, a temperature of the disposed feedstock material on the substrate using an auxiliary heat source, or a combination thereof.