Nippon Steel Sumitomo Metal Corporation

Nippon Steel Corporation

Taku Kagawa

Kazuhiro Takahashi

Kiyonori Tokuno

Koki Tanaka

Masanari Kimoto

Hiroshi Kihira

Takumi Nishimoto

Junko Imamura

Atsuhiko Kuroda

Takashi Domoto

Masao Kimura

Yuuichi Yosida

Jyunko Imamura

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 (I/(I+I)&#xd7;100 found from the maximum intensity of the X-ray diffraction peaks of TiO (I) and the maximum intensity of the X-ray diffraction peaks of metal titanium (I) in X-ray diffraction measured at an incident angle to the surface of 0.3&#xb0; 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.

Titanium material or titanium alloy material having surface electrical conductivity and method for producing the same, and fuel cell separator and fuel cell using the same

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&#x3a9;&#xb7;cmor less at a surface pressure of 10 kgf/cmbefore 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&#xb0; C. for four days.

Titanium or titanium alloy material for fuel cell separator having high contact conductivity with carbon and high durability, fuel cell separator including the same, and manufacturing method therefor

The composition ratio of a titanium hydride [I/(I+I)]&#xd7;100 found from the maximum intensity of metal titanium (I) and the maximum intensity of the titanium hydride (I) 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&#xb0; 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.

Titanium material or titanium alloy material having surface electrical conductivity, and fuel cell separator and fuel cell using the same

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.

Titanium material or titanium alloy material for fuel cell separator having high contact conductivity with carbon and high durability, fuel cell separator including the same, and fuel cell

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Tokyo, Japan

Taku Kagawa