# US 8,785,031 B2 · Polymer electrolyte fuel cell separator made of pure titanium or titanium alloy and method of production of same

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- Number: US 8,785,031 B2
- Document ID: US8785031B2
- Status: Granted
- Kind: B2
- Application number: 12/304,722
- Filed: 2007-06-15
- Published: 2009-08-06
- Granted: 2014-07-22
- Earliest claimed: 2006-06-15
- Assignees: Nippon Steel & Sumitomo Metal Corporation
- Applicants: Michio Kaneko; Kazuhiro Takahashi; Kiyonori Tokuno; Hiroshi Kihira; Wataru Hisada
- Inventors: Michio Kaneko; Kazuhiro Takahashi; Kiyonori Tokuno; Hiroshi Kihira; Wataru Hisada
- Web page: https://patentgrep.com/patent/US8785031B2

## CPC

- C23C 24/04: Impact or kinetic deposition of particles
- C23C 28/00: Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- H01M 8/0204: Non-porous and characterised by the material
- H01M 8/0206: Metals or alloys
- H01M 8/0208: Alloys
- H01M 8/0215: Glass; Ceramic materials
- H01M 8/0228: in the form of layered or coated products
- H01M 2008/1095: {Fuel cells with polymeric electrolytes}
- Y02E 60/50: Fuel cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- 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

## Abstract

The present invention provides a polymer electrolyte fuel cell separator made of pure titanium or a titanium alloy superior in contact resistance with carbon paper and a method of production of the same, that is, a separator having a surface layer part to which conductive compound particles are affixed, characterized in that the surface oxide has a thickness of 3 to 15 nm in range, an average carbon concentration in a range from an outermost surface, including the oxide layer, to a depth of 100 nm is 0.02 to 6 at %, and the conductive compound particles have an average particle size of 0.01 to 20 μm. Further, the method of production of the present invention is characterized by forming, blast treating a surface of the formed article by particles comprised of conductive compound particles of an average particle size of 0.01 to 20 μm covering a surface of superhard core particles, impregnating it by a nitric acid aqueous solution of a concentration of 15 to 71 mass % and a temperature of 40 to 100° C. for 30 seconds to 180 minutes by spraying or dipping, then washing it.

## Claims

### Claim 1

A polymer electrolyte fuel cell separator made of pure titanium or a titanium alloy having a surface layer part to which conductive compound particles are affixed, said polymer electrolyte fuel cell separator made of pure titanium or a titanium alloy characterized in that the pure titanium or titanium alloy has a surface oxide of a thickness of 3 to 15 nm in range, an average carbon concentration in a range from an outermost surface, including the oxide layer of the pure titanium or titanium alloy, to a depth of 100 nm is 0.4 to 6 at %, and said conductive compound particles have an average particle size of 0.01 to 20 μm and a density per unit area at a separator surface part of 1×108/cm2 or more, wherein said conductive compound particles comprise one or more of Cr2N, CrSi2, VB, V8C7, VN, TaN, TaC, and WN.