# US 11,440,049 B2 · Low friction coatings > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,049 B2 - Document ID: US11440049B2 - Status: Granted - Kind: B2 - Application number: 16/588,637 - Filed: 2019-09-30 - Published: 2021-04-01 - Granted: 2022-09-13 - Earliest claimed: 2019-09-30 - Assignees: Uchicago Argonne, LLC - Applicants: Uchicago Argonne, LLC - Inventors: Anirudha V. Sumant; Venkata Aditya Ayyagari - Web page: https://patentgrep.com/patent/US11440049B2 ## CPC - B05D 5/08: to obtain an anti-friction or anti-adhesive surface (rendering particulate materials free-flowing in general, e.g. making them hydrophobic B01J2/30) - C09D 1/00: Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances - B05D 1/02: performed by spraying - B05D 5/083: {involving the use of fluoropolymers} - B05D 7/14: to metal, e.g. car bodies (involving a chemical reaction between the metal and the coating C23) - C09C 1/44: Carbon - C09C 3/063: {Coating} - C09D 5/00: Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced {(electrically insulating plastics, resins or waxes H01B3/30)}; Filling pastes - C09D 7/61: inorganic - B05D 2202/10: based on Fe - B05D 2202/25: based on Al - B05D 2252/04: of definite length in a continuous process - B05D 2400/00: Indexing scheme for single layers or multilayers - B05D 2401/20: Aqueous dispersion or solution - B05D 2506/15: Polytetrafluoroethylene [PTFE] - C08K 3/042: {Graphene or derivatives, e.g. graphene oxides} - C08K 2003/385: {Binary compounds of nitrogen with boron} - B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02) - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) - C09C: TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES (treatment of materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone C04B14/00, C04B18/00, C04B20/00); PREPARATION OF CARBON BLACK {; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS} - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) ## Abstract A low friction, wear-resistant surface operable at high temperatures and high loads with a low coefficient of friction including boron nitride and graphene-oxide on steel or nanodiamonds and graphene on aluminum. The low friction, wear-resistant surface remains with a coefficient of friction in the superlubric regime at temperatures in between about 200° C. and 970° C. ## Claims ### Claim 1 A method comprising: preparing graphene-oxide by chemical exfoliation of polycrystalline graphite or highly-oriented pyrolytic graphite; suspending the prepared graphene-oxide in a solvent to form a mixture of at least 50 mg/L; adding at least 50 mg/L of boron nitride to the mixture; adding a functionalizer comprising polydopamine (“PDA”); sonicating the mixture to form a homogenous mixture; and disposing the homogeneous mixture by: spraying the homogeneous mixture on a substrate via a process of air-spray coating, wherein the substrate has a temperature of at least 110° C., forming a wet film on the substrate, and evaporating the solvent to form a dry coating layer, the dry coating layer reducing the friction of the substrate by greater than or equal to 50%. ### Claim 2 (depends on 1) The method of claim 1, wherein the graphene oxide and the boron nitride are in a range of ratios of about 1:1. ### Claim 3 (depends on 1) The method of claim 1, wherein the solvent is water. ### Claim 4 (depends on 1) The method of claim 1, wherein the solvent is oil-free. ### Claim 5 (depends on 1) The method of claim 1, wherein the substrate is boron steel. ### Claim 6 (depends on 1) The method of claim 1, wherein the temperature is about 275° C. ### Claim 7 (depends on 1) The method of claim 1, wherein the functionalizer is added prior to sonicating the mixture. ### Claim 8 (depends on 7) The method of claim 7, wherein the functionalizer further comprises Polyether ether ketone (“PEEK”). ### Claim 9 A method comprising: preparing a functionalizer solution comprising polydopamine; forming a solid lubricant mixture; sonicating the solid lubricant mixture to form a homogenous mixture; adding the functionalizer solution to the homogenous mixture, forming a liquid spray mixture; and disposing the liquid spray mixture by: spraying the liquid spray mixture on a substrate via a process of air-spray coating, forming a wet film on the substrate, and evaporating the solvent component to form a dry coating layer, the dry coating layer reducing the friction of the substrate by greater than or equal to 50%; wherein the dry coating layer comprises polydopamine and the solid lubricant. ### Claim 10 (depends on 9) The method of claim 9, wherein preparing a functionalizer solution comprises: mixing PDA powder with ethanol and water; adjusting the pH to 8.3; and polymerizing PDA. ### Claim 11 (depends on 10) The method of claim 10, wherein the polydopamine and solid lubricant are present in a substantially 1:1 ratio. ### Claim 12 (depends on 9) The method of claim 9, wherein the solid lubricant is selected from the group consisting of boron nitride and graphene oxide, nanodiamonds, molybdenum sulfide, graphene, and tungsten sulfide. ### Claim 13 (depends on 9) The method of claim 9, further comprising diluting the solid lubricant mixture with water. ### Claim 14 (depends on 9) The method of claim 9, wherein the substrate has a temperature at least about 110° C. ### Claim 15 (depends on 9) The method claim 9, wherein the substrate is boron steel. ### Claim 16 (depends on 9) The method claim 9, wherein the substrate is aluminum.