# US 7,407,717 B2 · Protective coating for substrates that are subjected to high temperatures and method for producing said coating > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,407,717 B2 - Document ID: US7407717B2 - Status: Granted - Kind: B2 - Application number: 10/545,886 - Filed: 2004-01-13 - Published: 2006-05-11 - Granted: 2008-08-05 - Earliest claimed: 2003-02-18 - Assignees: Forschungzentrum Julich GmbH - Inventors: Frank Tietz; Mohsine Zahid; Willem J. Quadakkers; Vladimir Shemet - Web page: https://patentgrep.com/patent/US7407717B2 ## CPC - C23C 8/02: Pretreatment of the material to be coated (C23C8/04 takes precedence) - C23C 10/18: using liquids, e.g. salt baths, liquid suspensions - C23C 10/30: using a layer of powder or paste on the surface (using liquid suspensions of solids C23C10/18) - C23C 26/00: Coating not provided for in groups C23C2/00 - C23C24/00 - H01M 8/0208: Alloys - H01M 8/0217: Complex oxides, optionally doped, of the type AMO3, A being an alkaline earth metal or rare earth metal and M being a metal, e.g. perovskites - H01M 8/0219: {Chromium complex oxides} - H01M 8/0228: in the form of layered or coated products - H01M 2008/1293: {Fuel cells with solid oxide electrolytes} - Y02E 60/50: Fuel cells - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - Y10T 428/12611: Oxide-containing component - Y10T 428/12618: Plural oxides - Y10T 428/12667: Oxide of transition metal or Al - 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) - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method is disclosed for producing a protective coating on a chromium oxide-forming substrate, which comprises the steps of: (a) applying on the chromium-oxide-forming substrate having at least one alloying addition selected from the group consisting of manganese, magnesium, and vanadium, a coating consisting essentially of at least one spinel-forming element selected from the group consisting of cobalt, nickel, copper and vanadium, (b) forming a chromium oxide layer at the substrate/applied coating interface, and (c) at a temperature of 500° C. to 1000° C. causing the diffusion of the at least one alloying addition through the chromium oxide layer and forming a compound thereof with the at least one spinel-forming element diffusing from the applied coating and forming between the chromium oxide layer on the substrate and the applied coating, a uniform, compact, adherent chromium-free gas-tight spinel layer. ## Claims ### Claim 1 A method of producing a protective layer on a substrate with the steps of: (a) applying on the chromium-oxide-forming substrate having at least one alloying addition selected from the group consisting of manganese, magnesium, and vanadium, a coating consisting essentially of at least one spinel-forming element selected from the group consisting of cobalt, nickel, copper and vanadium, (b) forming a chromium oxide layer at the substrate/applied coating interface, c) at a temperature of 500° C. to 1000° C. causing the diffusion of the at least one alloying addition through the chromium oxide layer and forming a compound thereof with the least one spinel-forming element diffusing from the applied coating and forming between the chromium oxide layer on the substrate and the applied coating, a uniform, compact, adherent chromium-free gas-tight spinel layer, said alloying addition and said applied coating containing sufficient reservoirs of said alloying addition and said spinel-forming element, respectively to heal any microcracks in the chromium-free spinel layer which forms during operation of a high temperature fuel cell. ### Claim 2 (depends on 1) The method according to claim 1 in which the applied coating is applied in the form of monoxides as a suspension or slurry by wet powder spraying, painting or screen printing on the chromium-oxide-forming substrate. ### Claim 3 (depends on 1) The method according to claim 1 in which the applied coating is applied in the form of CoO and CuO to the chromium-oxide-forming substrate. ### Claim 4 (depends on 1) The method according to claim 1 in which manganese as alloying addition from the substrate and cobalt as spinel-forming element from the applied coating form the chromium-free gas tight spinel layer according to the formula Co3-x-yMxMnyO4 where M=Ti, V, Mn, Fe, Ni, Cu; x<0.4 and 0