# US 9,039,821 B2 · Methods and compositions for coating aluminum substrates > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,039,821 B2 - Document ID: US9039821B2 - Status: Granted - Kind: B2 - Application number: 14/193,997 - Filed: 2014-02-28 - Published: 2014-07-10 - Granted: 2015-05-26 - Earliest claimed: 2008-05-09 - Assignees: Birchwood Laboratories, Inc. - Applicants: Birchwood Laboratories, Inc. - Inventors: William V. Block; David J. Halverson; John T. Nguyen - Web page: https://patentgrep.com/patent/US9039821B2 ## CPC - C09D 1/00: Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances - C23C 22/68: using aqueous solutions with pH between 6 and 8 - C23C 22/78: Pretreatment of the material to be coated - 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) - 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 The present invention relates to methods and compositions for coating aluminum substrates. In an embodiment, the invention includes a method of applying a coating on an aluminum substrate including contacting the aluminum substrate with a first solution. The first solution can include a zinc metal salt, a sugar acid or alkali metal salt thereof, and an alkali metal hydroxide. The method can also include contacting the aluminum substrate with a second solution. The second solution can include a molybdate salt, an alkanolamine, and a fluorine acid. Other embodiments are also included herein. ## Claims ### Claim 1 A kit for applying a coating exhibiting black color stability for a period of 60 days to an aluminum substrate, the kit comprising: a first solution comprising at least about 2 grams per liter of a zinc metal salt; at least about 2 grams per liter of a sugar acid selected from the group consisting of gluconic acid, glucoheptonic acid, and alkali metal salts thereof; at least about 20 grams per liter of an alkali metal hydroxide; and a second solution comprising at least about 20 grams per liter of a molybdate salt; at least about 10 grams per liter of an alkanolamine; and at least about 2 grams per liter of a fluorine acid. ### Claim 2 (depends on 1) The kit of claim 1, the first solution further comprising at least about 0.5 grams per liter of an iron metal salt; at least about 2 grams per liter of a carboxylic acid or alkali metal salt thereof; and at least 1 gram per liter of an oxidizing agent. ### Claim 3 A composition for applying a coating exhibiting black color stability for a period of 60 days on an aluminum substrate the solution comprising: at least about 2 grams per liter of a zinc metal salt; at least about 0.5 grams per liter of an iron metal salt; at least about 2 grams per liter of a carboxylic acid or alkali metal salt thereof; at least about 2 grams per liter of a sugar acid selected from the group consisting of gluconic acid, glucoheptonic acid, and alkali metal salts thereof; at least about 20 grams per liter of an alkali metal hydroxide; and at least about 1 gram per liter of an oxidizing agent. ### Claim 4 (depends on 1) The kit of claim 1, the first solution further comprising: an iron metal salt, a carboxylic acid or alkali metal salt thereof, and an oxidizing agent. ### Claim 5 (depends on 1) The kit of claim 1, the zinc metal salt comprising zinc (II) oxide. ### Claim 6 (depends on 4) The kit of claim 4, the iron metal salt comprising an iron (III) salt. ### Claim 7 (depends on 6) The kit of claim 6, the iron (III) salt comprising FeCl3. ### Claim 8 (depends on 2) The kit of claim 2, the carboxylic acid selected from the group consisting of glycolic acid, malic acid, tartaric acid, and citric acid. ### Claim 9 (depends on 2) The kit of claim 2, the carboxylic acid or alkali metal salt thereof comprising one or more of sodium tartrate, potassium tartrate, and sodium-potassium tartrate. ### Claim 10 (depends on 1) The kit of claim 1, the alkali metal hydroxide selected from the group consisting of sodium hydroxide, potassium hydroxide, and lithium hydroxide. ### Claim 11 (depends on 2) The kit of claim 2, the oxidizing agent comprising an alkali metal nitrate. ### Claim 12 (depends on 1) The kit of claim 1, the molybdate salt comprising ammonium heptamolybdate. ### Claim 13 (depends on 1) The kit of claim 1, the alkanolamine selected from the group consisting of monoethanolamine, triethanolamine, and 2-amino-2-methyl-1-propanol. ### Claim 14 (depends on 1) The kit of claim 1, the alkanolamine comprising 2-amino-2-methyl-1-propanol. ### Claim 15 (depends on 1) The kit of claim 1, the fluorine acid selected from the group consisting of fluoroboric acid and fluorosilicic acid.