Abstract: In a titanium material or a titanium alloy material, in an oxide film formed on a surface of a titanium or a titanium alloy, the composition ratio of TiO (ITiO/(ITi+ITiO)×100 found from the maximum intensity of the X-ray diffraction peaks of TiO (ITiO) and the maximum intensity of the X-ray diffraction peaks of metal titanium (ITi) in X-ray diffraction measured at an incident angle to the surface of 0.3° is 0.5% or more. A titanium material or a titanium alloy material, and a fuel cell separator and a polymer electrolyte fuel cell having good contact-to-carbon electrical conductivity and good durability can be provided.

Abstract: A titanium or titanium alloy material for a separator of a polymer electrolyte fuel cell having high contact conductivity with carbon and high durability, and including an oxide film formed on a titanium or titanium alloy substrate by a stabilization treatment performed after a passivation treatment, and one or more kinds of conductive materials selected from carbide, nitride, carbonitride, and boride of tantalum, titanium, vanadium, zirconium, and chromium, the conductive materials being dispersed in the oxide film and having a major axis diameter of from 1 nm to 100 nm. A contact resistance value with a carbon paper is 20 m?·cm2 or less at a surface pressure of 10 kgf/cm2 before and after an accelerated deterioration test in which the titanium or titanium alloy material is immersed in a sulfuric acid aqueous solution having an adjusted pH of 4 at 80° C. for four days.

Abstract: The composition ratio of a titanium hydride [ITi—H/(ITi+ITi—H)]×100 found from the maximum intensity of metal titanium (ITi) and the maximum intensity of the titanium hydride (ITi—H) of the X-ray diffraction peaks measured at a surface of a titanium or a titanium alloy at an incident angle to the surface of 0.3° is 55% or more, a titanium oxide film is formed on an outermost surface of the titanium or the titanium alloy, and C is at 10 atomic % or less, N is at 1 atomic % or less, and B is at 1 atomic % or less in a position where the surface has been subjected to sputtering of 5 nm with argon. The titanium oxide film is formed by performing stabilization treatment after performing passivation treatment in prescribed aqueous solutions, and has a thickness of 3 to 10 nm.

Abstract: A titanium or titanium alloy material for a fuel cell separator has a surface shape in which a plurality of projections are distributed, and a titanium oxide film on a surface of the projections. Fine projections are assumed to increase the contact conductivity remarkably. By increasing contact conductivity with carbon and durability of a titanium or titanium alloy material for a fuel cell separator, the lifetime of a fuel cell may be increased. The material has high usability in the cell manufacturing industry.

Abstract: A titanium material comprises: a plate-like matrix made of titanium or a titanium alloy and having a rough surface on which minute protrusions are formed; a surface oxide coating film formed along the rough surface and containing one or more titanium oxides; and a tip covering formed on the surface oxide coating film in an area comprising a tip of the minute protrusion and containing one or more noble metals. A composition ratio of TiO [ITiO/(ITi+ITiO)×100] determined from maximum intensity ITiO of diffraction peaks of TiO and maximum intensity ITi of diffraction peaks of metal Ti in an X-ray diffraction intensity curve of the surface oxide coating film is more than or equal to 0.5%.

Abstract: A composite metal foil in which the surface of a titanium foil or a titanium alloy foil is coated with an electrically conductive layer; in the composite metal foil, an electrically conductive film in which TiO is dispersed in an oxide film and the TiO composition ratio [ITiO/(ITi+ITiO)] found from the maximum intensity of the diffraction peaks of TiO (ITiO) and the maximum intensity of the diffraction peaks of metal titanium (ITi) out of the X-ray diffraction peaks of the surface of the titanium foil or the titanium alloy foil is 0.5% or more is formed on the surface of the titanium foil or the titanium alloy foil, and the electrically conductive layer consists of, in mass %, silver particles with an average particle size of not less than 10 nm and not more than 500 nm: 20% to 90%, a dispersant: 0.2% to 1.0%, and the balance: an acrylic resin or an epoxy resin, and has a thickness of 5 to 50 ?m.

Abstract: In a titanium material or a titanium alloy material, in an oxide film formed on a surface of a titanium or a titanium alloy, the composition ratio of TiO (ITiO/(ITi+ITiO)×100 found from the maximum intensity of the X-ray diffraction peaks of TiO (ITiO) and the maximum intensity of the X-ray diffraction peaks of metal titanium (ITi) in X-ray diffraction measured at an incident angle to the surface of 0.3° is 0.5% or more. A titanium material or a titanium alloy material, and a fuel cell separator and a polymer electrolyte fuel cell having good contact-to-carbon electrical conductivity and good durability can be provided.

Abstract: The composition ratio of a titanium hydride [ITi—H/(ITi+ITi—H)]×100 found from the maximum intensity of metal titanium (ITi) and the maximum intensity of the titanium hydride (ITi—H) of the X-ray diffraction peaks measured at a surface of a titanium or a titanium alloy at an incident angle to the surface of 0.3° is 55% or more, a titanium oxide film is formed on an outermost surface of the titanium or the titanium alloy, and C is at 10 atomic % or less, N is at 1 atomic % or less, and B is at 1 atomic % or less in a position where the surface has been subjected to sputtering of 5 nm with argon. The titanium oxide film is formed by performing stabilization treatment after performing passivation treatment in prescribed aqueous solutions, and has a thickness of 3 to 10 nm.

Abstract: [Object] To increase contact conductivity with carbon and durability of a titanium or titanium alloy material for a fuel cell separator so as to increase the lifetime of a fuel cell. [Solution] Provided is a titanium or titanium alloy material for a fuel cell separator having a surface shape in which a plurality of projections are distributed, and a titanium oxide film on a surface of the projections. Fine projections are assumed to increase the contact conductivity remarkably. The present invention has high usability in the cell manufacturing industry.

Abstract: [Object] To increase contact conductivity with carbon and durability of a titanium or titanium alloy material for a fuel cell separator so as to increase the lifetime of a fuel cell. [Solution] Provided is a titanium or titanium alloy material for a fuel cell separator having a surface shape in which a plurality of projections are distributed, and a titanium oxide film on a surface of the projections. Fine projections are assumed to increase the contact conductivity remarkably. The present invention has high usability in the cell manufacturing industry.

Abstract: [Object] To provide a titanium or titanium alloy material for a separator of a polymer electrolyte fuel cell having high contact conductivity with carbon and high durability. [Solution] The titanium or titanium alloy material includes an oxide film formed on a titanium or titanium alloy substrate by stabilization treatment performed after passivation treatment, and one or more kinds of conductive materials selected from carbide, nitride, carbonitride, and boride of tantalum, titanium, vanadium, zirconium, and chromium, the conductive materials being dispersed in the oxide film and having a major axis diameter from 1 nm to 100 nm. A contact resistance value with a carbon paper is 20 m?·cm2 or less at a surface pressure of 10 kgf/cm2 before and after an accelerated deterioration test in which the titanium or titanium alloy material is immersed in a sulfuric acid aqueous solution having an adjusted pH of 4 at 80° C. for four days.