# US 7,611,615 B2 · Process for manufacturing a metal electrode > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,611,615 B2 - Document ID: US7611615B2 - Status: Granted - Kind: B2 - Application number: 10/480,875 - Filed: 2002-06-13 - Published: 2004-10-07 - Granted: 2009-11-03 - Earliest claimed: 2001-06-14 - Assignees: Cerel (Ceramics Technologies) Ltd. - Inventors: Nissim Cohen; Israel Schuster; Ludmila Cherniak; Tali Peled - Web page: https://patentgrep.com/patent/US7611615B2 ## CPC - H01G 9/052: Sintered electrodes - H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10) ## Abstract The present invention provides a process for manufacturing a porous metal electrode, wherein the porosity degree is in the range of 30 to 50% and the metal is capable of forming a stable, uniform, oxide layer having a dielectric constant greater than 25 (k≧25), preferably selected from the group consisting of tantalum and niobium, comprising a substantially uniform porous layer of deposited said metal particles thereon. The present invention further relates to a stable suspension for electrophoretically homogeneously deposition of said metal. ## Claims ### Claim 1 An electrophoretic process for producing a porous metal electrode, wherein said electrode comprises a metal, capable of forming a stable oxide layer having a dielectric constant equal to or greater than 20, selected from the group consisting of tantalum and niobium, wherein said metal electrode comprises a substantially uniform porous layer of deposited particles of said metal having a porosity degree in the range of 30 to 50% deposited thereon, which process comprises the steps of: (a) providing a metal suspension of said metal in a polar solvent; (b) immersing a temporary cathode and a counter electrode in said suspension, and running a pre-processing initiating step by electrifying said temporary cathode as a deposition electrode; (c) replacing said temporary cathode with a new deposition electrode wherein said new deposition electrode is constituted by a metal foil; and (d) electrifying said new deposition electrode, so to cause electrophoretic homogeneous deposition of said metal particles onto the surface of said new deposition electrode. ### Claim 2 (depends on 1) An electrophoretic process according to claim 1, wherein the polar solvent is selected from the group consisting of an organic polar solvent, water and a mixture of water and polar organic solvent(s). ### Claim 3 (depends on 1) An electrophoretic process according to claim 1, wherein the metal is tantalum and said polar solvent is n-butanol. ### Claim 4 (depends on 1) An electrophoretic process according to claim 1, wherein the metal is niobium and said polar solvent is ethanol. ### Claim 5 (depends on 1) An electrophoretic process according to claim 1, wherein the metal suspension contains at least one additive chosen from the group consisting of pH and conductivity adjustment agents for controlling the pH and conductivity of said metal suspension. ### Claim 6 (depends on 5) An electrophoretic process according to claim 5, wherein said additive comprises phosphate ester. ### Claim 7 (depends on 5) An electrophoretic process according to claim 5, wherein said additive comprises AlCl3. ### Claim 8 (depends on 5) An electrophoretic process according to claim 5, wherein said additive comprises poly-diallyldimethylammonium chloride (PDADMAC). ### Claim 9 (depends on 5) An electrophoretic process according to claim 5 wherein the pH and the conductivity are controlled to be in the range of 3-11 and in the range of 0.1-250 μS/cm respectively. ### Claim 10 (depends on 5) An electrophoretic process according to claim 5, wherein the metal suspension further contains at least one dispersant. ### Claim 11 (depends on 10) An electrophoretic process according to claim 10, wherein said dispersant is acetyl acetone. ### Claim 12 (depends on 10) An electrophoretic process according to claim 10, wherein said additive and said dispersant are phosphate ester and acetyl acetone, respectively. ### Claim 13 (depends on 1) An electrophoretic process according to claim 1, wherein the counter electrode selected from the group consisting of rhodium, palladium, platinum, tantalum and niobium. ### Claim 14 (depends on 1) An electrophoretic process according to claim 1, wherein the metal suspension contains phosphate ester and acetyl acetone and the counter electrode is selected from rhodium, palladium and platinum. ### Claim 15 (depends on 1) An electrophoretic process according to claim 1, wherein the metal suspension contains AlCl3 and the counter electrode comprises a metal selected from niobium and tantalum. ### Claim 16 (depends on 1) An electrophoretic process according to claim 1, wherein the metal is tantalum, the tantalum suspension contains phosphate ester and acetyl acetone, and the counter electrode is selected from rhodium, palladium and platinum. ### Claim 17 (depends on 1) An electrophoretic process according to claim 1, wherein the metal is tantalum, the tantalum suspension contains an additive and/or dispersant selected from the group consisting of phosphate ester, acetyl acetone, AlCl3 and PDADMAC, and the counter electrode is selected from rhodium, palladium and platinum. ### Claim 18 (depends on 1) An electrophoretic process according to claim 1, wherein the metal is niobium and niobium suspension contains phosphate ester, and the counter electrode is Pt, Pd, or Nb. ### Claim 19 (depends on 1) An electrophoretic process for producing a porous metal electrode according to claim 1, wherein the substantially uniform porous layer of deposited particles has a green density in the range of 25 to 40%.