# US 2008/0187767 A1 · Oxidation resistant coatings, processes for coating articles, and their coated articles > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0187767 A1 - Document ID: US20080187767A1 - Status: Published application - Kind: A1 - Application number: 11/603,622 - Filed: 2006-11-21 - Published: 2008-08-07 - Earliest claimed: 2006-11-21 - Assignees: United Technologies Corporation - Inventors: Xia Tang; Tania Bhatia; David C. Jarmon; Wayde R. Schmidt; Harry E. Eaton; John G. Smeggil - Web page: https://patentgrep.com/patent/US20080187767A1 ## CPC - C04B 41/89: for obtaining at least two superposed coatings having different compositions - C04B 41/009: {characterised by the material treated} - C04B 41/52: Multiple coating or impregnating {multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation} - C23C 24/10: with intermediate formation of a liquid phase in the layer - C23C 26/00: Coating not provided for in groups C23C2/00 - C23C24/00 - C23C 30/00: Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process (C23C26/00, C23C28/00 take precedence) - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - Y10T 428/12611: Oxide-containing component - 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 - 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) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A process for applying an oxidation resistant coating to an article includes the steps of mixing at least about 10% by volume to up to about 99% by volume of a slurry at least one silica based material having a viscosity of about 1×102 poise to about 1×107 poise at a temperature of about 1,292° F. (700° C.) to about 3,272° F. (1,800° C.) at least about 1% by volume to up to about 90% by volume of the slurry at least one oxygen scavenger, and a liquid medium to form the slurry; coating an article with the slurry to form a slurry coated article; and heat treating under an inert atmosphere the slurry coated article to form an article having at least one oxidation resistant coating layer containing the at least one oxygen scavenger. ## Claims ### Claim 1 A process for applying an oxidation resistant coating to an article, comprising: mixing at least about 10% by volume to up to about 99% by volume of a slurry comprising at least one silica based material having a viscosity of about 1×102 poise to about 1×107 poise at a temperature of about 1,292° F. (700° C.) to about 3,272° F. (1,800° C.) at least about 1% by volume to up to about 90% by volume of said slurry comprising at least one oxygen scavenger, and a liquid medium to form said slurry; coating an article with said slurry to form a slurry coated article; and heat treating under an inert atmosphere said slurry coated article to form an article having at least one oxidation resistant coating layer containing said at least one oxygen scavenger. ### Claim 2 (depends on 1) The process of claim 1, wherein mixing further comprises adding a viscosity modifier in an amount sufficient to rheologically control a viscosity of said slurry during said heat treatment step. ### Claim 3 (depends on 2) The process of claim 2, wherein said viscosity modifier is selected from the group consisting of refractory materials, metal oxides, metal silicates, and mixtures thereof. ### Claim 4 (depends on 1) The process of claim 1, wherein said at least one oxygen scavenger is a silicide of any one or more of the following: molybdenum, tantalum, chromium, titanium, hafnium, zirconium, yttrium, and mixtures thereof; or a boride of any one or more of the following: molybdenum, tantalum, chromium, titanium, hafnium, zirconium, yttrium, and mixtures thereof; or both of any one or more of said silicides and any one or more of said borides. ### Claim 5 (depends on 1) The process of claim 1, wherein said at least one oxygen scavenger is a silicide of any one of the following: molybdenum, tantalum, chromium, titanium, hafnium, zirconium, yttrium, and mixtures thereof; and a boride of any one of the following: molybdenum, tantalum, chromium, titanium, hafnium, zirconium, yttrium, and mixtures thereof. ### Claim 6 (depends on 1) The process of claim 1, wherein mixing comprises a mechanical mixing process comprising at least one of the following: ball mixing, grinding, high energy milling, attrition milling, centrifugal mixing, and combinations thereof. ### Claim 7 (depends on 1) The process of claim 1, wherein mixing comprises a manual mixing process. ### Claim 8 (depends on 1) The process of claim 1, wherein coating comprises at least one of the following processes: thermal spraying, chemical vapor deposition, physical vapor deposition, electrophoretic deposition, electrostatic deposition, preceramic polymer pyrolysis, sol-gel, slurry coating, dipping, air-brushing, sputtering, slurry painting, and combinations thereof. ### Claim 9 (depends on 1) The process of claim 1, wherein coating comprises a low pressure plasma spraying process or a high velocity oxygen fuel spraying process. ### Claim 10 (depends on 1) The process of claim 1, wherein said coating step comprises a painting process. ### Claim 11 (depends on 10) The process of claim 10, further comprising drying said slurry coated article at about 662° F. (350° C.) for about 30 minutes to about 60 minutes prior to heat treating said slurry coated article. ### Claim 12 (depends on 1) The process of claim 1, wherein heat treating comprises heating said slurry coated substrate at about 1,000° F. (538° C.) to about 2,552° F. (1,400° C.) for a period of time sufficient to form said oxidation resistant coating. ### Claim 13 (depends on 1) The process of claim 1, wherein said silica based material comprises a particle size range of about 150 mesh to about 325 mesh. ### Claim 14 (depends on 1) The process of claim 1, wherein said at least one oxygen scavenger comprises a particle diameter size range of about 0.5 microns to about 50 microns. ### Claim 15 (depends on 1) The process of claim 1, wherein said silica based material includes a functional group acting as a viscosity modifier. ### Claim 16 (depends on 1) The process of claim 1, wherein said liquid medium comprises at least one of the following: water, alcohol, terpineol, colloidal silica, inorganic containing solvent, and organic containing solvent. ### Claim 17 (depends on 1) The process of claim 1, further comprising applying upon said oxidation resistant coating layer a top coat layer comprising at least one of the following: refractory oxide material, refractory carbide material, refractory boride material, refractory silicide material, and mixtures thereof. ### Claim 18 (depends on 17) The process of claim 17, wherein said refractory oxide material is selected from the group consisting of TaxOy (where x=1 to 3 and y=1 to 5), NbxOy (where x=1 to 3 and y=1 to 5), MgO, CaO, SrO, BaO, SiO2, HfO2, TiO2, ZrO2, Al2O3, Y2O3, La2O3, rare earth oxides, and mixtures thereof. ### Claim 19 (depends on 17) The process of claim 17, wherein applying comprises at least one of the following processes: thermal spraying, chemical vapor deposition, physical vapor deposition, electrophoretic deposition, electrostatic deposition, preceramic polymer pyrolysis, sol-gel, slurry coating, dipping, air-brushing, sputtering, slurry painting, high velocity oxygen fuel spraying, and low pressure plasma spraying. ### Claim 20 A coated article, comprising: an article having at least one surface having disposed thereupon an oxidation resistant coating comprising a silica based material having a viscosity of about 1×102 poise to about 1×107 poise at a temperature of about 1,292° F. (700° C.) to about 3,272° F. (1,800° C.) and at least one or more oxygen scavengers dispersed therein. ### Claim 21 (depends on 20) The coated article of claim 20, wherein said at least one oxygen scavenger is a silicide of any one or more of the following: molybdenum, tantalum, chromium, titanium, hafnium, zirconium, yttrium, and mixtures thereof; or a boride of any one or more of the following: molybdenum, tantalum, chromium, titanium, hafnium, zirconium, yttrium, and mixtures thereof; or both of any one or more of said suicides and any one or more of said borides. ### Claim 22 (depends on 20) The coated article of claim 20, further comprising a top coat layer disposed upon said oxidation resistant coating, said top coat layer comprising at least one of the following: refractory oxide material, refractory carbide material, refractory boride material, refractory silicide material, and mixtures thereof. ### Claim 23 (depends on 22) The coated article of claim 22, wherein said refractory oxide material is selected from the group consisting of TaxOy (where x=1 to 3 and y=1 to 5), NbxOy (where x=1 to 3 and y=1 to 5), MgO, CaO, SrO, BaO, SiO2, HfO2, TiO2, ZrO2, Al2O3, Y2O3, La2O3, rare earth oxides, and mixtures thereof. ### Claim 24 (depends on 20) The coated article of claim 20, wherein said article comprises any one of the following: silicon containing ceramics, silicon containing alloys, and mixtures thereof. ### Claim 25 (depends on 24) The coated article of claim 24, wherein said silicon containing ceramics are selected from the group consisting of silicon nitride, silicon carbide, silicon carbonitride, silicon oxycarbides, silicon carbide composites, silicon nitride composites, silicon oxynitrides, silicon aluminum oxynitrides, silicon nitride ceramic matrix composites, and mixtures thereof. ### Claim 26 (depends on 24) The coated article of claim 24, wherein said silicon containing alloys are selected from the group consisting of molybdenum silicon alloys, niobium silicon alloys, iron silicon alloys, iron silicon alloys, cobalt silicon alloys, nickel silicon alloys, tantalum silicon alloys, refractory metal silicon alloys, and mixtures thereof. ### Claim 27 (depends on 20) The coated article of claim 20, wherein said oxidation resistant coating has a thickness of between about 0.1 and about 300 mils. ### Claim 28 (depends on 20) The coated article of claim 20, wherein said oxidation resistant coating has a thickness of between about 0.1 and about 10 mils. ### Claim 29 (depends on 20) The coated article of claim 20, wherein the article comprises any one of the following: turbine engine components, hypersonic engine components, and hypersonic components. ### Claim 30 (depends on 20) The coated article of claim 20, wherein the article comprises any one of the following: nozzles, flaps, seals and shrouds of turbine engines; leading edges and heat exchangers of hypersonic engines; and airfoil surfaces of hypersonic components.