# US 12,766,596 B2 · Coated metal foil of copper or a copper alloy and method for producing a coated metal foil of copper or a copper alloy > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,766,596 B2 - Document ID: US12766596B2 - Status: Granted - Kind: B2 - Application number: 18/997,754 - Filed: 2024-03-11 - Published: 2025-08-14 - Granted: 2026-10-20 - Earliest claimed: 2023-05-08 - Assignees: Cunex GmbH - Applicants: Cunex GmbH - Inventors: Sri Krishna Bhogaraju; Gordon Elger - Web page: https://patentgrep.com/patent/US12766596B2 ## CPC - B22F 7/04: with one or more layers not made from powder, e.g. made from solid metal - B22F 1/052: characterised by a mixture of particles of different sizes or by the particle size distribution - B22F 1/068: Flake-like particles - B22F 1/103: containing an organic binding agent comprising a mixture of, or obtained by reaction of, two or more components other than a solvent or a lubricating agent - B22F 1/16: Metallic particles coated with a non-metal (coated with lubricating or binding agents or with organic material B22F1/10) - B22F 7/064: {using an intermediate powder layer} - B22F 2007/042: {characterised by the layer forming method} - B22F 2301/10: Copper - B22F 2304/10: Micron size particles, i.e. above 1 micrometer up to 500 micrometer - B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER ## Abstract A coated metal foil for forming a copper-containing interlayer between a first solid substrate and a second solid substrate or between a solid substrate. The coated metal foil includes a metal foil of copper or of a first copper alloy or of a copper plated nickel-iron alloy. The metal foil has a first surface and a second surface. The metal foil has a composition coated on the first surface and/or the second surface of the metal foil. The composition includes an organic binder and flakes of copper or the first or a second copper alloy. The flakes include internal pores. ## Claims ### Claim 1 A coated metal foil for forming a copper-containing interlayer between a first solid substrate and a second solid substrate or between a solid substrate and the metal foil, wherein the coated metal foil comprises or consists of a metal foil of copper or of a first copper alloy or of a copper plated nickel-iron alloy, wherein the metal foil has a first surface and a second surface, and a composition coated on the first surface and/or the second surface of the metal foil, wherein the composition comprises or consists of the following components: an organic binder and flakes of copper, of the first copper alloy or of a second copper alloy, wherein the flakes comprise internal pores. ### Claim 2 (depends on 1) The coated metal foil according to claim 1, wherein the composition is coated on the first surface and a further composition is coated on the second surface, wherein the further composition comprises or consists of the organic binder or a further organic binder and the flakes or further flakes of copper, of the first copper alloy or of the second copper alloy, wherein the further flakes comprise internal pores. ### Claim 3 (depends on 1) The coated metal foil according to claim 1, wherein the flakes of copper, of the first copper alloy or of the second copper alloy have a mean intraparticle pore density in a range of 7 internal pores/μm2 to 30 internal pores/μm2. ### Claim 4 (depends on 1) The coated metal foil according to claim 1, wherein grains in the metal foil at the first surface and/or the second surface of the metal foil have an average grain size of at least 2 μm and at most 100 μm and/or grains in the flakes have an average grain size of at least 20 nm and at most 200 nm and/or wherein a ratio of the average grain size of the grains in the flakes to the average grain size of the grains at the first surface and/or the second surface of the metal foil in each case does not exceed 0.002. ### Claim 5 (depends on 1) The coated metal foil according to claim 1, wherein the first copper alloy is bronze or brass and/or wherein the metal foil has a thickness of at least 5 μm and at most 150 μm. ### Claim 6 (depends on 1) The coated metal foil according to claim 1, wherein the flakes are of the second copper alloy and the second copper alloy is bronze or brass, and/or wherein the flakes have a mean particle size D50 determined by laser granulometry of at most 5 μm. ### Claim 7 (depends on 1) The coated metal foil according to claim 1, wherein the flakes have a multi-layer lamellar structure. ### Claim 8 (depends on 1) The coated metal foil according to claim 1, wherein the flakes are coated with stearic acid, wherein the total weight of stearic acid in relation to the total weight of the flakes coated with stearic acid at most 1.5 wt. %. ### Claim 9 (depends on 1) The coated metal foil according to claim 1, wherein the organic binder a terpineol, a primary alcohol, a diol, a triol, a polymeric glycol or a mixture of at least two of a terpineol, a primary alcohol, a diol, a triol and a polymeric glycol. ### Claim 10 (depends on 1) The coated metal foil according to claim 1, wherein the composition further comprise(s) turpentine or a polar organic solvent. ### Claim 11 (depends on 1) The coated metal foil according to claim 1, wherein 10% to 100%, of an area of the first surface and/or of an area of the second surface of the metal foil are independently from each other coated with the composition, and/or wherein the composition is coated on the first surface and/or the second surface of the metal foil in each case independently from each other in a thickness of at least 1 μm and at most 500 μm. ### Claim 12 (depends on 1) A method for producing the coated metal foil according to claim 1 comprising the steps of a) providing the metal foil of copper or of a first copper alloy or of a copper plated nickel-iron alloy, wherein the metal foil has a first surface and a second surface, the flakes of copper or of the first copper alloy or of a second copper alloy, wherein the flakes comprise internal pores, and the organic binder, b) mixing the flakes and the organic binder for obtaining a composition, and c) applying the composition obtained in step b) to the first surface and/or the second surface of the metal foil for obtaining the coated metal foil. ### Claim 13 (depends on 12) The method according to claim 12, wherein the metal foil is of bronze or brass and/or has a thickness of at least 5 μm and at most 150 μm, and/or the flakes are of the second copper alloy and the second copper alloy is bronze or brass, and/or the flakes have a mean particle size D50 determined by laser granulometry of at most 5 μm and/or the flakes have a multi-layer lamellar structure and/or the flakes are coated with stearic acid, wherein the total weight of stearic acid in relation to the total weight of the flakes coated with stearic acid is at most 1.5 wt. % and/or the organic binder is a terpineol, a primary alcohol, a diol, a triol, a polymeric glycol or a mixture of at least two of a terpineol, a primary alcohol, a diol, a triol and a polymeric glycol. ### Claim 14 (depends on 12) The method according to claim 12, wherein before step c) the metal foil is heated to a first pre-treatment temperature in the range of 170° C. to 220° C. for at least 1 minute and at most 2 hours and cooled to a second pre-treatment temperature in the range of 15° C. to 40° C. ### Claim 15 (depends on 12) The method according to claim 12, wherein after step c) the metal foil is heated to a pre-drying temperature in the range of 100° C. to 160° C. for at least 1 minute and at most 30 minutes or wherein during step c) and after the composition obtained in step b) was applied to the first surface, the metal foil is heated to a pre-drying temperature in the range of 100° C. to 160° C. for at least 1 minute and at most 30 minutes followed by a cooling step, application of the composition obtained in step b) to the second surface and heating the metal foil to the pre-drying temperature in the range of 100° C. to 160° C. for at least 1 minute and at most 30 minutes. ### Claim 16 (depends on 1) Use of the coated metal foil according to claim 1 for forming a copper-containing interlayer between two surfaces of solid substrates or between a surface of a solid substrate and the metal foil, for forming a conductive path on a solid substrate or for substrate attachment.