Abstract: A titanium material including a base metal made of pure titanium or a titanium alloy and a titanium oxide film formed on the base metal. Peak intensities obtained by thin-film X-ray diffraction analysis performed on an outer layer of the titanium material using an incident angle of 0.3° satisfy (I(104)+I(200))/I(101)?0.08?0.004×I(200), where I(104) is the peak intensity resulting from a plane (104) of a Ti2O3 phase, I(200) is the peak intensity resulting from a plane (200) of a TiO phase, I(101) is the peak intensity resulting from a plane (101) of an ?-Ti phase, and 0<I(104), 0?I(200), and 0<I(101). The titanium material is inexpensive and has both the electrical conductivity and corrosion resistance.

Abstract: Provided are a stainless steel sheet with good corrosion resistance, low contact resistance and good press workability without the use of expensive materials such as gold or rare metals, and a method of manufacture the same. A method of manufacturing a stainless steel sheet includes: preparing a slab having a chemical composition including, in mass %: 20 to 26% Cr, up to 0.1% N, up to 2.0% Si, etc. (step S1); performing hot rolling and cold rolling on the slab to produce a rolled steel sheet with a thickness of 50 to 200 ?m (step S2); an annealing step in which the rolled steel sheet is annealed and cooled in a gas atmosphere containing nitrogen (step S3); and pickling the rolled steel sheet after the annealing step with a solution containing a non-oxidizing acid (step S4). The stainless steel sheet has an N content of 0.6 to 2.0% by mass.

Abstract: A titanium material includes a base material made of pure titanium or a titanium alloy; and a carbon layer covering a surface of the base material. The carbon layer includes non-graphitizable carbon, and has an R value (I1350/I1590) of 2.0 or more and 3.5 or less in the Raman spectroscopy using laser having a wavelength of 532 nm. Where I1350 is peak intensity at a wave number of around 1.35×105 m?1 in a Raman spectrum, and I1590 is peak intensity at a wave number of around 1.59×105 m?1 in a Raman spectrum. According to this titanium material, it is possible to realize low contact resistance by the carbon layer. Moreover, this titanium material is not susceptible to surface oxidation and capable of maintaining low contact resistance even when exposed to noble potential.

Abstract: Provided are a stainless steel sheet with good corrosion resistance, low contact resistance and good press workability without the use of expensive materials such as gold or rare metals, and a method of manufacture the same. A method of manufacturing a stainless steel sheet includes: preparing a slab having a chemical composition including, in mass %: 20 to 26% Cr, up to 0.1% N, up to 2.0% Si, etc. (step S1); performing hot rolling and cold rolling on the slab to produce a rolled steel sheet with a thickness of 50 to 200 ?m (step S2); an annealing step in which the rolled steel sheet is annealed and cooled in a gas atmosphere containing nitrogen (step S3); and pickling the rolled steel sheet after the annealing step with a solution containing a non-oxidizing acid (step S4). The stainless steel sheet has an N content of 0.6 to 2.0% by mass.

Abstract: A titanium material including a base metal made of pure titanium or a titanium alloy and a titanium oxide film formed on the base metal. Peak intensities obtained by thin-film X-ray diffraction analysis performed on an outer layer of the titanium material using an incident angle of 0.3° satisfy (I(104)+I(200))/I(101)?0.08?0.004×I(200), where I(104) is the peak intensity resulting from a plane (104) of a Ti2O3 phase, I(200) is the peak intensity resulting from a plane (200) of a TiO phase, I(101) is the peak intensity resulting from a plane (101) of an ?-Ti phase, and 0<I(104), 0?I(200), and 0<I(101). The titanium material is inexpensive and has both the electrical conductivity and corrosion resistance.

Abstract: A titanium product for a separator of a proton exchange membrane fuel cell according to the present invention includes: a base material that consists of commercially pure titanium; a first oxide layer that is formed in a surface layer of the titanium product, consists of TiO2 of a rutile crystallinity, and has a thickness of 0.1 to 1.5 nm; and a second oxide layer that is formed between the base material and the first oxide layer, consists of TiOx (1<x<2), and has a thickness of 3 to 20 nm. This titanium product is suitable to be used as a separator of a proton exchange membrane fuel cell that has a high corrosion resistance in an environment in a fuel cell, is capable of keeping a low contact resistance with an electrode consisting of carbon fiber and the like, and is inexpensive.

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: Provided is a metallic material including: a base metal made of a metal; a metal compound layer stacked on a surface of the base metal, the metal compound layer mainly containing a compound of at least one transition metal in the fourth period and oxygen; a platinum group portion dispersed on a surface of the metal compound layer, the platinum group portion mainly containing at least one platinum group element; and a platinum group compound coating film which covers the platinum group portion, the platinum group compound coating film mainly containing a compound of at least one platinum group element and oxygen. The at least one platinum group element contained in the platinum group portion is preferably one or more of Ru, Rh, Os, and Ir.

Abstract: This titanium product includes a base metal, and a complex oxide film formed on the surface of the base metal. The base metal has a chemical composition consisting of, by mass %, platinum group elements: 0 to 0.15%, rare earth elements: 0 to 0.1%, and a balance: Ti and impurities. The complex oxide film contains a complex oxide of Ti and one or more elements selected from La, Ce, Nd, Sr and Ca, and has a thickness of 1 to 20 nm. The average grain size at the base metal surface is preferably from 20 to 300 ?m.

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: There is provided a titanium product for a separator of a polymer electrolyte fuel cell (PEFC). The titanium product includes a substrate made of a titanium or a titanium alloy, and a passivation film formed on a surface of the substrate, wherein the passivation film includes a Li-containing titanium oxide layer in its surface layer. This titanium product can keep a low contact resistance with an electrode film and is inexpensive.

Abstract: A titanium product for a separator of a proton exchange membrane fuel cell according to the present invention includes: a base material that consists of commercially pure titanium; a first oxide layer that is formed in a surface layer of the titanium product, consists of TiO2 of a rutile crystallinity, and has a thickness of 0.1 to 1.5 nm; and a second oxide layer that is formed between the base material and the first oxide layer, consists of TiOx (1<x<2), and has a thickness of 3 to 20 nm. This titanium product is suitable to be used as a separator of a proton exchange membrane fuel cell that has a high corrosion resistance in an environment in a fuel cell, is capable of keeping a low contact resistance with an electrode consisting of carbon fiber and the like, and is inexpensive.

Abstract: A stainless steel sheet used for a separator of a polymer electrolyte fuel cell, wherein the steel sheet has a volume ratio of M2B boride-based metal precipitates of 8% or higher and a volumetric-basis particle-size frequency distribution of M2B boride-based metal precipitates having sphere-equivalent diameters of 6.72 ?m or less of 99.5% or higher, in a surface layer which has a depth of 0.2 t from at least one of surfaces (t is an overall thickness of the steel sheet), and the steel sheet has an apparent density of 0.995 or higher, assuming a real density to be 1. A polymer electrolyte fuel cell in which the stainless steel sheet is used for a separator is given an excellent cell performance without high-cost surface treatment such as expensive gold plating for the reduction of the contact resistance of a surface.

Abstract: A duplex stainless steel is provided that has a chemical composition comprising, by mass %, C: 0.03% or less, Si: 1.0% or less, Mn: 1.0% or less, P: 0.04% or less, S: 0.01% or less, Cu: 0.1 to 1.0%, Ni: 5.0 to 7.5%, Cr: 22.0 to 26.0%, W: 6.0 to 12.0%, N: 0.20 to 0.32%, Mo: 0.01% or less, and a balance: Fe and impurities, in which a metal micro-structure contains, by area ratio, 0.40 to 0.60 of an ?-phase, with a balance being a ?-phase and 0.01 or less of other phases.

Abstract: A ferritic stainless steel material contains, by mass %, C: 0.02 to 0.15%, Si: 0.01 to 1.5%, Mn: 0.01 to 1.5%, P: 0.035% or less, S: 0.01% or less, Cr: 22.5 to 35.0%, Mo: 0.01 to 6.0%, Ni: 0.01 to 6.0%, Cu: 0.01 to 1.0%, N: 0.035% or less, V: 0.01 to 0.35%, B: 0.5 to 1.0%, Al: 0.001 to 6.0%, rare earth metal: 0 to 0.10%, Sn: 0 to 2.50%, and the balance: Fe and impurities, and a value calculated in mass % as {Cr+3×Mo?2.5×B?17×C} ranges from 20 to 45%. The ferritic stainless steel material has a parent phase comprising only a ferritic phase. At least composite metallic precipitates including M23C6 carbide-based metallic precipitates precipitated on surfaces and at peripheries of M2B boride-based metallic precipitates serving as precipitation nuclei are dispersed and exposed on a parent phase surface.

Abstract: Provided is a metallic material including: a base metal made of a metal; a metal compound layer stacked on a surface of the base metal, the metal compound layer mainly containing a compound of at least one transition metal in the fourth period and oxygen; a platinum group portion dispersed on a surface of the metal compound layer, the platinum group portion mainly containing at least one platinum group element; and a platinum group compound coating film which covers the platinum group portion, the platinum group compound coating film mainly containing a compound of at least one platinum group element and oxygen. The at least one platinum group element contained in the platinum group portion is preferably one or more of Ru, Rh, Os, and Ir.

Abstract: A stainless steel member for a separator of a solid polymer fuel cell has excellent cell properties with little deterioration in performance over long periods of operation without worsening of the corrosion resistance of a stainless steel separator. The stainless steel member has a stainless steel base metal, and a passive film and electrically conductive precipitates both provided on a surface of the stainless steel base metal. The electrically conductive precipitate penetrates the passive film and includes a substance originating from the stainless steel base metal. An electrically conductive layer comprising a nonmetallic electrically conductive substance is preferably provided on the surface of the passive film, and the electrically conductive layer is preferably electrically connected to the stainless steel base member through the electrically conductive precipitates.

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.