WO2020054072A1 - Feuille de titane et son procédé de production - Google Patents

Feuille de titane et son procédé de production Download PDF

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WO2020054072A1
WO2020054072A1 PCT/JP2018/034274 JP2018034274W WO2020054072A1 WO 2020054072 A1 WO2020054072 A1 WO 2020054072A1 JP 2018034274 W JP2018034274 W JP 2018034274W WO 2020054072 A1 WO2020054072 A1 WO 2020054072A1
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compound
titanium
less
titanium foil
layer
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PCT/JP2018/034274
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English (en)
Japanese (ja)
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琢 香川
孝 飯島
徳野　清則
一浩 ▲高▼橋
禰宜　教之
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日本製鉄株式会社
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Priority to PCT/JP2018/034274 priority Critical patent/WO2020054072A1/fr
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C14/00—Alloys based on titanium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
    • C22F1/18—High-melting or refractory metals or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • 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
    • C23C28/00—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
    • C23C28/04—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 only coatings of inorganic non-metallic material
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • 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
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/24—Nitriding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0206—Metals or alloys
    • H01M8/0208—Alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0215—Glass; Ceramic materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0223—Composites
    • H01M8/0228—Composites in the form of layered or coated products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • 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
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a titanium foil and a method for producing the same.
  • Fuel cells are being developed as driving power sources for vehicles and stationary power generation devices, against the background of recent energy problems and environmental problems such as global warming.
  • a polymer electrolyte fuel cell that can operate at a low temperature of 100 ° C. or less has attracted attention, and its development and commercialization have been promoted.
  • This polymer electrolyte fuel cell generally has a membrane electrode assembly (MEA: Membrane Electrode Assembly) in which a catalyst layer serving as an anode and a catalyst layer serving as a cathode are arranged with a proton-conductive electrolyte membrane interposed therebetween.
  • a gas diffusion layer made of carbon is disposed outside the membrane electrode assembly, and a separator is disposed outside the gas diffusion layer.
  • This basic structure is called a unit cell.
  • a fuel cell is usually configured by stacking a required number of unit cells to achieve a required output.
  • an oxidizing gas such as oxygen or air is supplied to a cathode side from gas flow paths of separators provided on an anode side and a cathode side, respectively.
  • a fuel gas such as hydrogen is supplied to the anode side.
  • the oxidizing gas and the fuel gas are supplied to the catalyst layer via the gas diffusion layer, respectively, and an energy difference (potential difference) between an electrochemical reaction occurring in the anode catalyst layer and an electrochemical reaction occurring in the cathode catalyst layer is performed.
  • an energy difference potential difference between an electrochemical reaction occurring in the anode catalyst layer and an electrochemical reaction occurring in the cathode catalyst layer is performed.
  • hydrogen gas is used as fuel gas
  • oxygen gas is used as oxidizing gas.
  • the potential of the separator becomes equal to the potential of the catalyst layer, and particularly at the cathode, the potential is maintained at a high potential of about 1 V even if the overvoltage generated due to various causes is subtracted, and the operating temperature of the fuel cell becomes 60 to 90 ° C. Since the temperature is maintained, the separator is used under a strong oxidizing condition.
  • the polymer electrolyte fuel cell is operated under a strongly acidic condition having a pH of 4 or less and under an environment in which fluorine derived from the electrolyte membrane and halogen ions such as chloride ions taken in from the atmosphere coexist.
  • fluorine derived from the electrolyte membrane and halogen ions such as chloride ions taken in from the atmosphere coexist.
  • a so-called non-conductive coating it is essential to form a highly corrosion-resistant coating on the metal surface of the separator, a so-called non-conductive coating.
  • the non-conductive film formed on the metal surface is usually formed as an oxide of a metal component, that is, a metal oxide as a main component.
  • metal oxides are often non-conductors, and special measures are required to develop the conductivity required for the separator.
  • Patent Document 1 an invention using a special stainless steel in which a conductive compound is precipitated in a steel material (Patent Document 1) and an invention using a titanium-based material in which TiB-based precipitates are dispersed in titanium (Patent Document 2) ), And many other inventions have been proposed so far.
  • Patent Document 3 on a titanium or titanium alloy substrate (titanium substrate layer), any of tantalum, titanium, vanadium, zirconium or chromium carbide, nitride, carbonitride and boride is used. It has an oxide film (conductive surface layer) in which a conductive material having a major axis diameter of 1 nm or more and 100 nm or less is dispersed, and is immersed in an aqueous sulfuric acid solution at pH 4 at 80 ° C. for 4 days.
  • oxide film conductive surface layer
  • a titanium base layer and a surface layer are formed, the titanium base layer has a recrystallized structure, and the surface layer is formed of Ti in which O, C, and N are dissolved.
  • O, C, and N only a compound-containing titanium layer (conductive surface layer) having a thickness of less than 1 ⁇ m in which a compound formed by Ti and Ti is mixed, or the compound-containing titanium layer; It consists of a passivation film (conductive surface layer composed of a compound-containing titanium layer and a passivation film) having a thickness of less than 5 nm formed on its surface, the passivation film is appropriately destroyed, and its regeneration is suppressed.
  • a titanium plate material for a fuel cell separator titanium foil for a separator
  • a method for producing the same have been proposed that can reliably achieve a low contact resistance.
  • Patent Document 5 proposes a composite metal foil for a fuel cell separator in which the surface of a titanium foil or a titanium alloy foil is coated with a predetermined conductive layer, and a method for producing the same.
  • a titanium substrate made of titanium or a titanium alloy is subjected to a dipping treatment in a non-oxidizing acid or a cathodic electrolytic treatment and a subsequent heat treatment, whereby X-rays are applied to the surface of the titanium substrate.
  • the present inventors first conceived of using a fuel cell under a more severe use environment than previously assumed.
  • a conventional accelerated deterioration test for example, “Evaluation test of immersing in a sulfuric acid aqueous solution of pH 4 at 80 ° C.
  • Patent Document 3 A new accelerated degradation test to investigate conductivity and corrosion resistance under even more severe conditions than that of "Impact test at 80 ° C for 4 days (96 hours) containing 100 ppm of fluoride ions at pH 3-sulfuric acid aqueous solution for 4 days (96 hours)" (Test for immersion in a sulfuric acid aqueous solution at a concentration of 0.005 wt% at pH 3 at 90 ° C. for 100 hours for evaluation) was set. In this new accelerated aging test, what kind of conductivity and corrosion resistance each titanium foil for a separator described in Patent Documents 3 to 5 has been examined.
  • the present inventors next examined in detail the causes of the titanium foils of Patent Documents 3 to 5 not exhibiting the desired conductivity and corrosion resistance in a new accelerated deterioration test. Focused on the presence of a TiC compound in each of the conductive surface layers (the oxide film of Patent Document 3, the compound-containing titanium layer of Patent Document 4, and the oxide film of Patent Document 5).
  • the TiC compound dissolves relatively easily in the new accelerated aging test described above and is passivated in the conductive surface layer to form the non-conductive passive material TiO 2 or by dissolution of the TiC compound. It has been found that the oxidation of pure titanium in the metal proceeds, and as a result, the conductivity of the conductive surface layer is reduced or the suppression of corrosion is impaired.
  • the reason why the TiC compound is mixed in the conductive surface layer is not necessarily clear, but the titanium plate material made of titanium or a titanium alloy used as a raw material is originally solid. It is considered that dissolved carbon and carbon derived from the rolling oil used during cold rolling of the titanium sheet material are considered to be carbon sources. The solid solution carbon and the carbon derived from the rolling oil in these titanium sheet materials are chemically bonded to Ti on the surface of the titanium sheet material during cold rolling and / or bright annealing treatment to form a TiC compound. It is considered something.
  • this TiC compound is inevitably generated on the surface of the titanium sheet material by bright annealing after cold rolling, and therefore, as long as the cold rolling and bright annealing are performed in the manufacturing process, the TiC compound is produced. It is considered that the generation of the TiC compound is inevitable even if the rolling oil is washed after the cold rolling of the sheet material.
  • TiO compound> TiN compound> TiC compound are superior in the order of corrosion resistance from the viewpoint of corrosion resistance, and TiC compound> TiN compound> TiO compound from the viewpoint of conductivity. Excellent in order. Focusing on the fact that the TiN compound has sufficient conductivity for use as a separator, further studies were conducted on developing a titanium foil for a separator having excellent performance in the above-mentioned accelerated deterioration test.
  • the present invention is as follows. [1] In mass%, C: 0.080% or less, H: 0.013% or less, O: 0.40% or less, N: 0.050% or less, Fe: 0.50% or less, A base material layer having a chemical composition that is a balance of Ti and impurities, With a surface layer having conductivity formed on the surface of the base material layer, The surface layer is a Ti compound including a TiN compound and a TiO compound, and not including a TiC compound. Titanium foil.
  • the surface layer is measured by an X-ray diffraction method, one or both diffraction peaks of a TiN compound and a Ti 2 N compound are observed, no diffraction peaks of other compounds are observed, and the surface layer
  • the XPS spectrum is measured from the side, one of the peaks of the TiO 2 compound and the peak of one or both of the TiO x compounds is observed, and other than these, the peak of Ti is not observed.
  • the surface layer has a thickness of 20 nm to 500 nm; The titanium foil of the above [1] or [2].
  • the surface layer provides the X-ray diffraction spectrum, the ratio between the peak P a2 of the peak P a1 and TiN compound of Ti 2 N compound (P a1 / P a2) is from 1.6 to 2.6
  • the titanium foil according to any one of the above [1] to [3].
  • the conductive surface layer has a ratio (P b1 / P b2 ) of the peak P b1 of the TiO 2 compound to the peak P b2 of the TiO x compound in the XPS spectrum of Ti2p of 1.7 to 2.8. is there, The titanium foil according to any one of the above [1] to [4].
  • a method for producing a titanium foil comprising: [8] After the step (2) and before the step (3), a light-volume annealing treatment is performed.
  • the step (3) includes: As an acid treatment liquid, a mixed solution of sulfuric acid and hydrogen peroxide, using nitric acid or hydrogen peroxide, The method for producing a titanium foil according to the above [7] or [8].
  • a titanium foil having excellent conductivity and corrosion resistance can be provided.
  • the titanium foil of the present invention not only the conductivity is excellent, but also the conductivity is excellent even under the severe use environment of the fuel cell which is exposed to a higher temperature due to the increase in capacity and compactness.
  • a separator of a polymer electrolyte fuel cell that can exhibit corrosion resistance can be manufactured. Further, according to the present invention, it is possible to provide a method for producing the above-mentioned titanium foil.
  • FIG. 1 is a schematic diagram showing a cross-sectional structure of a titanium foil according to the present invention.
  • FIG. 13 is a transmission electron microscope (TEM: Transmission Electron Microscope) image of a partial cross section of the titanium foil of No. 13, (a) shows a TEM image, (b) shows the position of each compound in the TEM image of (a). Is shown.
  • FIG. 3 is a schematic diagram showing a cross-sectional structure of the annealed titanium plate material.
  • FIG. 4 is a schematic diagram showing a cross-sectional structure of the first acid-treated titanium plate material.
  • FIG. 5 is a schematic diagram showing a cross-sectional structure of a titanium foil obtained by performing a second acid treatment on a first acid-treated titanium plate material.
  • FIG. 13 is a transmission electron microscope (TEM: Transmission Electron Microscope) image of a partial cross section of the titanium foil of No. 13, (a) shows a TEM image, (b) shows the position of each compound in the TEM image of (a
  • FIG. 6 is a schematic diagram showing a cross-sectional structure of a titanium sheet material (second annealed titanium sheet material) obtained by performing the second annealing on the first acid-treated titanium sheet material.
  • FIG. 7 is a schematic diagram showing a cross-sectional structure of a titanium foil obtained by performing a second acid treatment on a second annealed titanium plate material.
  • the titanium foil according to the present invention is used, for example, for a separator of a polymer electrolyte fuel cell.
  • the titanium foil according to the present invention includes a base layer 1 and a conductive surface layer 2 formed on the surface of the base layer 1.
  • the surface layer 2 is a Ti compound containing a TiN compound 2a and a TiO compound 2b, but not containing a TiC compound.
  • the titanium foil according to the present invention does not contain a TiC compound that is relatively easily dissolved in the above-mentioned new accelerated deterioration test, so that it can exhibit excellent conductivity and corrosion resistance even under a severe use environment of a fuel cell.
  • the base material layer 1 is, by mass%, C: 0.080% or less, H: 0.013% or less, O: 0.40% or less, N: 0.050% or less, Fe: 0.50% or less, It has the chemical composition of the remainder Ti and impurities.
  • JIS Class 1 to Class 4 are defined in JIS H4600: 2012.
  • JIS Class 1 means C: 0.08% or less, H: 0.013% or less, O: 0.15% or less, N: 0.03% or less, Fe: 0.20% or less, composition of balance Ti and impurities Having.
  • JIS Class 2 means C: 0.08% or less, H: 0.013% or less, O: 0.20% or less, N: 0.03% or less, Fe: 0.25% or less, balance of Ti and impurities. Having a composition.
  • JIS Class 3 means C: 0.08% or less, H: 0.014% or less, O: 0.30% or less, N: 0.05% or less, Fe: 0.30% or less, balance of Ti and impurities Having a composition.
  • JIS Class 4 means C: 0.08% or less, H: 0.013% or less, O: 0.40% or less, N: 0.05% or less, Fe: 0.50% or less, balance of Ti and impurities. Having a composition.
  • the thickness of the base material layer 1 may be appropriately set according to its use, and is, for example, 0.03 mm or more and 0.1 mm or less. A preferred lower limit is 0.03 mm, and a preferred upper limit is 0.05 mm.
  • the surface layer 2 is a conductive surface layer, and includes a Ti compound containing a TiN compound 2a and a TiO compound 2b and not containing a TiC compound.
  • the thickness of the surface layer 2 is preferably 20 nm or more and 500 nm or less. If it is less than 20 nm, it is difficult to secure sufficient conductivity and corrosion resistance, and if it exceeds 500 nm, the conductivity may be reduced.
  • the preferred lower limit of the surface layer 2 is 100 nm, and the preferred upper limit is 300 nm. As shown in FIG.
  • the surface layer 2 is composed of a layer composed of a TiN compound 2a as an inner layer close to the surface of the substrate layer 1, and a TiO compound 2b as an outer layer remote from the surface of the substrate layer 1. And a layer to be formed.
  • the surface layer 2 having such a configuration is used in an acid environment or a high-temperature environment, excellent corrosion resistance is exhibited by the TiO compound 2b constituting the outer layer, and the excellent conductivity of the TiN compound 2a constituting the inner layer is exhibited. Can be maintained for a long period of time. Since it is difficult to strictly define the thickness of the inner layer composed of the TiN compound 2a and the thickness of the outer layer composed of the TiO compound 2b, the thickness is evaluated by the average value of the thickness measured by the following method.
  • a thin slice sample processed to a thickness (for example, about 100 nm) that can be observed with a TEM by a method such as FIB is prepared, and an image obtained by TEM observation of this sample shows that a TiN compound is randomly selected at 50 locations.
  • the thicknesses of 2a and TiO compound 2b are measured, and the average value is defined as the thickness of each layer.
  • the thickness of the inner layer made of the TiN compound 2a is preferably 20 nm or more and 499 nm or less. If it is less than 20 nm, it is difficult to secure sufficient conductivity, and if it exceeds 499 nm, it tends to crack during press working, and the durability may not be satisfied.
  • a preferred lower limit is 100 nm, and a preferred upper limit is 300 nm.
  • the thickness of the outer layer made of the TiO compound 2b is preferably 1 nm or more and 20 nm or less. If it is less than 1 nm, it is difficult to secure sufficient corrosion resistance, and if it exceeds 20 nm, the conductivity may be reduced.
  • a preferred lower limit is 2 nm, and a preferred upper limit is 15 nm.
  • TiN compound 2a The fact that the Ti compound 2 contains the TiN compound 2a can be confirmed, for example, by observing a peak by an X-ray diffraction method. That is, when one or both diffraction peaks of the TiN compound and the Ti 2 N compound are measured by the X-ray diffraction method, it can be determined that the Ti compound 2 includes the TiN compound 2a.
  • the measurement by the X-ray diffraction method described above was performed using an X-ray diffractometer (SmartLab manufactured by Rigaku Corporation) using an X-ray source: CoK ⁇ , an X-ray output: 40 kV and 135 mA, an incident angle ( ⁇ ): 0.5 °, Scattering angle (2 ⁇ ): 1.0 °, detector: scintillation counter, scan range: 5 ° to 110 °, scan speed: 2 ° / min, step: 0.02 ° to X-ray sample was performed by a thin film X-ray diffraction method (thin film XRD method) in which the diffraction angle 2 ⁇ was measured by scanning while fixing the incident angle ( ⁇ ) of the sample.
  • X-ray diffractometer SmartLab manufactured by Rigaku Corporation
  • the TiN compound 2a the X-ray diffraction spectrum
  • the ratio between the peak P a2 of the peak P a1 and TiN compound of Ti 2 N compound (P a1 / P a2) is from 1.6 to 2.6 .
  • the ratio (P a1 / P a2 ) is less than 1.6, the conductivity may be reduced.
  • the ratio (P a1 / P a2 ) exceeds 2.6, the conductivity is high but the corrosion resistance is reduced. Might be.
  • the TiO compound 2b does not show a peak in X-ray diffraction and has an amorphous structure.
  • metal Ti (0 valence of Ti) or Ti in a trivalent ion state may be observed. Since these Tis may cause a problem of dissolution in the operating environment of the polymer electrolyte fuel cell, in the present invention, TiO 2 (tetravalent ion of Ti) compound and TiO x (divalent ion of Ti) are used. ) It is preferable that a peak of Ti other than the compound is not observed.
  • the ratio of the peak P b1 of the TiO 2 compound to the peak P b2 of the TiO x compound (P b1 / P b2 ) in the XPS spectrum of Ti 2p is preferably 1.7 to 2.8. .
  • the ratio (P b1 / P b2 ) is less than 1.7, the conductivity is high, but the corrosion resistance may decrease.
  • the ratio (P b1 / P b2 ) exceeds 2.8, the conductivity decreases.
  • TiC compound The fact that the Ti compound does not contain the TiC compound can be confirmed, for example, by observing a peak by an X-ray diffraction method. That is, when the diffraction peak of the TiC compound is not observed when measured by the X-ray diffraction method, it can be determined that the Ti compound does not include the TiC compound.
  • 2 ⁇ (deg) 35 to 39 ° is regarded as the baseline, the average value of the intensity and the deviation ⁇ are calculated, and the intensity of the target compound is calculated.
  • It can be defined as a state in which the peak intensity obtained by subtracting the baseline of the diffraction line is larger than 2 ⁇ , and there is no peak whose half-value width of the peak is smaller than 3 °.
  • the measurement by the X-ray diffraction method is the same as the measurement of the TiN compound.
  • the layer 2 is preferably a layer in which the peak of the TiO 2 compound and the peak of the TiO x compound are observed, and other Ti peaks are not observed.
  • the titanium foil according to the present invention has a desired thickness by cold rolling a titanium plate material of about 0.2 to 0.5 mm. Cold rolling is performed in the presence of rolling oil.
  • rolling oil As a method of cold-rolling the titanium sheet material to a predetermined thickness in the presence of the rolling oil, general cold rolling adopted when manufacturing a titanium foil from a titanium sheet material may be used.
  • rolling oil contains carbon.
  • a washing step such as degreasing is usually performed.
  • carbon derived from the rolling oil cannot be completely removed, and 0.001 to 0.1% by mass of carbon is added to titanium material.
  • Inherent Carbon present in the titanium material is deposited on the surface of the titanium material as a TiC compound in a subsequent annealing step.
  • first annealing treatment Light-volume annealing treatment
  • bright annealing is performed on the cold-rolled titanium sheet in a nitrogen gas atmosphere to obtain an annealed titanium sheet having the titanium compound layer 20 formed on the surface of the titanium sheet.
  • the Ti compound 20 formed on the surface of the annealed titanium plate material 10 is composed of a TiN compound 21 and a TiC compound 22.
  • the TiN compound 21 is mainly derived from N in the atmosphere, and the TiC compound 22 is derived from C contained in the annealed titanium plate material 10.
  • the annealing temperature is, for example, not less than 600 ° C.
  • the annealing time is, for example, not less than 10 seconds and not more than 360 seconds. If the time is less than 10 seconds, a sufficient TiN compound 21 cannot be formed on the surface of the titanium plate material 10, and excellent conductivity may not be obtained.
  • the time exceeds 360 seconds when the time exceeds 360 seconds, the TiN compound 21 becomes too thick, so that the TiN compound 21 is easily cracked at the time of press working, and the durability may not be satisfied.
  • a preferred lower limit is 15 seconds
  • a preferred upper limit is 300 seconds.
  • the annealing time and the annealing temperature are correlated with each other. If the annealing temperature is 840 ° C., a suitable annealing time is 10 seconds. If the annealing is performed at a higher temperature, the suitable treatment time becomes shorter. However, the composition and thickness of the surface layer formed on the surface of the base material are varied and become uncontrollable. Therefore, a combination of 840 ° C. and 10 seconds is set.
  • lowering the annealing temperature increases the annealing time, but at 600 ° C., 360 seconds is the optimum processing time.
  • the processing time needs to be further extended.
  • the processing time exceeds 360 seconds, the influence of impurities in the atmosphere occurs, so that 360 seconds is the upper limit and the corresponding processing temperature of 600 ° C. is the lower limit of the annealing temperature.
  • the annealing atmosphere is a nitrogen atmosphere. This is because the Ti compound layer 20 containing a large amount of the TiN compound is formed on the surface of the titanium plate.
  • a first acid treatment is performed on the annealed titanium sheet material 10 to obtain a first acid-treated titanium sheet material 11 from which the TiC compound 22 in the Ti compound layer 20 has been removed.
  • the TiC compound 22 is completely or mostly removed, and as shown in FIG. 4, the Ti compound layer 20 formed on the surface of the first acid-treated titanium plate 11 is basically made of the TiN compound 21. Be composed.
  • an acid such as nitric acid or citric acid is used, it is presumed that a slight amount of TiO compound is formed, but it is difficult to detect the TiO compound, and its substantial existence can be ignored.
  • a relatively weak acid aqueous solution such as an organic acid having a hydroxy, thiol, or enol as a characteristic group
  • a relatively weak acid aqueous solution such as an organic acid having a hydroxy, thiol, or enol as a characteristic group
  • an aqueous solution of a strong protic inorganic acid having a pKa value of 2 or less or a carboxyl group-containing organic acid having a PKa value of 5 or less is required as a treatment solution.
  • Specific examples include aqueous solutions of nitric acid, sulfuric acid, phosphoric acid, hydrochloric acid, hydrobromic acid, oxalic acid, acetic acid, citric acid, and the like.
  • the processing temperature is 80 ° C. or more and 95 ° C. or less.
  • a more preferred lower limit is 85 ° C, and a more preferred upper limit is 90 ° C.
  • the processing time is preferably set to 5 minutes or more and 20 minutes or less.
  • a preferred lower limit is 10 minutes, and a preferred upper limit is 15 minutes.
  • the concentration of the solution is not limited, but is preferably 1% by mass or more and 60% by mass or less.
  • the pH of the solution is not limited, but is preferably 0.05 or more and 3.0 or less.
  • the first acid-treated titanium plate 11 is subjected to a second acid treatment, and the surface of the Ti compound 20 containing the TiN compound 21 and the TiO compound 23 but not containing the TiC compound 22 is produced.
  • a titanium foil 12 comprising a layer is obtained.
  • the TiC compound 22 remaining in the Ti compound 20 is completely removed, and as shown in FIG. 5, the Ti compound layer 20 formed on the surface of the titanium foil 12 includes the TiN compound 21 and the TiO compound. 23.
  • the purpose of the second acid treatment is to oxidize titanium to form a TiO compound 23.
  • TiO compound 23 Although the reason why the TiO compound 23 is formed is not necessarily clear, some of the TiN compounds 21 relatively inferior in durability among the TiN compounds 21 formed at the time of annealing elute during the second acid treatment, It is thought that it is deposited as titanium oxide (TiO compound) 23 and covers the outermost surface.
  • a mixed solution of sulfuric acid and hydrogen peroxide generally called piranhaic acid.
  • piranhaic acid a mixed solution of sulfuric acid and hydrogen peroxide generally called piranhaic acid.
  • piranhaic acid has a strong oxygen-imparting property, and can bind oxygen to the surface of the first acid-treated titanium plate material 11 to form an oxide film.
  • oxidizing agents such as nitric acid, a mixed solution of nitric acid and hydrogen peroxide, and dichromates and permanganates can be used in addition to piranhaic acid.
  • the processing temperature is preferably set to 80 ° C. or more and 95 ° C. or less. A more preferred lower limit is 85 ° C, and a more preferred upper limit is 90 ° C.
  • the processing time is preferably set to 5 minutes or more and 20 minutes or less. A preferred lower limit is 10 minutes, and a preferred upper limit is 15 minutes.
  • the concentration of the solution is not limited, but is preferably 1% by mass or more and 60% by mass or less.
  • the pH of the solution is not limited, but is preferably 0.05 or more and 3.0 or less.
  • the titanium foil according to the present invention can be manufactured by performing at least the steps (1) to (4) described above.
  • a part of the TiN compound 21 in the Ti compound 20 is dissolved.
  • the amount of the TiN compound 21 dissolved also increases, and a gap is formed between the TiN compounds 21.
  • a part of the TiN compound 21 is oxidized to obtain the TiO compound 23. Therefore, a sufficient amount of the TiN compound 21 may not be secured after the second acid treatment.
  • the first acid treatment after the first acid treatment, light annealing (second annealing) is performed before the second acid treatment to compensate for the TiN compound 21 reduced by the first acid treatment, as shown in FIG. It is preferable to form a layer of the compound 21 and obtain the second annealed titanium plate 13. If the second acid treatment is performed after the light acid annealing after the first acid treatment, the inner layer composed of the dense TiN compound 21 and the outer layer composed of the dense TiO compound 23 as shown in FIG. Thus, the titanium foil 14 having the surface layer 20 having the following structure can be obtained.
  • the temperature and time conditions of the light-volatilizing annealing are the same as those of the light-volatilizing annealing (first annealing) shown in the above (1). However, if the Ti compound layer 20 containing a large amount of a TiN compound is formed on the surface of the titanium plate material in the first light annealing (first annealing), the second annealing may be performed in an argon gas atmosphere.
  • the titanium foil manufactured as described above was subjected to the new accelerated deterioration test described above, that is, a test in which the titanium foil was immersed in a sulfuric acid aqueous solution having a pH of 3 at 90 ° C. for 100 hours to evaluate the contact resistance.
  • pressure 1.0 MPa is not more 5.5m ⁇ ⁇ cm 2 or less, moreover, conductivity and corrosion resistance contact resistance after the test (surface pressure 1.0 MPa) and excellent under severe conditions of 5.5m ⁇ ⁇ cm 2 or less Demonstrate.
  • the four types of JIS-standard titanium plates shown in Table 1 were cold-rolled to a thickness of 0.1 mm in the presence of rolling oil, and the obtained cold-rolled titanium plates were prepared under the conditions shown in Tables 2 to 5. The treatment was performed to obtain a titanium foil having a surface layer.
  • TiC Versus 00-031-1400
  • TiC compound TiC compound, TiN compounds (Ti 2 N, TiN), and TiO compounds as well as confirming the presence of (TiO 2)
  • Ti 2 N Compound It was determined the ratio of the peak P a2 of the peak P a1 and TiN compound (P a1 / P a2).
  • X-ray photoelectron spectroscopy For the obtained titanium foil, using an XPS apparatus (Quantum 2000 manufactured by PHI), irradiated X-ray: single crystal spectroscopy AlK ⁇ , X-ray spot and size: 300 ⁇ m ⁇ 300 ⁇ m, binding energy range: 450 to 475 eV, and X Linear output: Measured under the measurement conditions of 15 KV and 25 W, confirm the presence of the TiO compound (TiO2, TiOx) from the obtained XPS spectrum of Ti2p, separate the waveform of this spectrum, and exclude the background by the Iterated Shirley method.
  • TiO2 TiO2
  • the contact resistance value is based on a value of 5.5 m ⁇ ⁇ cm 2 or less.
  • the contact resistance value (unit: m ⁇ ⁇ cm 2 ) was measured by the same method as the above-described measurement of the contact resistance value.
  • the contact resistance value is based on a value of 5.5 m ⁇ ⁇ cm 2 or less.
  • FIG. 2 shows an image obtained by preparing an observation sample by FIB and observing a cross section of the titanium foil No. 13 at a magnification of 100,000 using a transmission electron microscope (TEM).
  • TEM transmission electron microscope
  • a scale bar is shown in the image.
  • a portion that looks black is the base material layer 1, and the surface layer 2 is confirmed thereon.
  • the portion surrounded by the solid line is the TiN compound 2a, and the portion surrounded by the dotted line is the TiO compound 2b.
  • a layer of the TiN compound 2a is confirmed on the base material layer 1.
  • the TiO compound 2b layer has low contrast in the TEM image of the thin section, the TiO compound layer covering TiN is partially confirmed at a thickness of about several nm.
  • the presence of the TiO compound layer was quantitatively evaluated by a 2p spectrum of Ti in XPS. Then, in the titanium foil of Example 3, from the measurement results of the contact resistance before and after the accelerated deterioration test, the layer of the TiO compound 2b covers the entire surface of the layer of the TiN compound 2a. Is determined.
  • each of 2 to 8, 12 to 14, 16 to 20, 22, 23, 25 to 27, 34, 35, 38 to 43, 48 to 51, 53, 54, 57 and 58 has a chemical composition of the base material layer.
  • the Ti compound includes a TiN compound and a TiO compound, and does not include TiC.
  • the contact resistance value was 5.5 m ⁇ ⁇ cm 2 or less before and after the accelerated deterioration test, and the film had excellent conductivity and corrosion resistance.
  • No. 1, 9 to 11, 15, 21, 24, 28 to 33, 36, 37, 44 to 47, 52, 55, and 56 whether the chemical composition of the base material layer does not satisfy the range specified in the present invention,
  • the Ti compound contains TiC. Therefore, in any of the examples, at least the contact resistance value after the accelerated deterioration test exceeded 5.5 m ⁇ ⁇ cm 2 .

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Abstract

L'invention concerne une feuille de titane 14 comprenant : une couche de substrat 1 ayant une composition chimique comprenant 0,080 % en masse ou moins de C, 0,013 % en masse ou moins de H, 0,40 % en masse ou moins de O, 0,050 % en masse ou moins de N, 0,50 % en masse ou moins de Fe, et le reste étant du Ti et des impuretés ; et une couche de surface 20 qui a une conductivité et est formée sur la surface de la couche de substrat 1. La couche de surface 20 est un composé Ti comprenant un composé TiN 21 et un composé TiO 23 et ne comprenant pas de composé TiC. Cette feuille de titane 14 présente une excellente conductivité et une excellente résistance à la corrosion même dans un environnement d'utilisation rigoureux dans lequel une pile à combustible a une capacité accrue et une taille réduite et est exposée à des températures plus élevées, et est ainsi appropriée pour être utilisée pour un séparateur dans une pile à combustible à polymère solide.
PCT/JP2018/034274 2018-09-14 2018-09-14 Feuille de titane et son procédé de production WO2020054072A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0568537B2 (fr) * 1984-05-11 1993-09-29 Sumitomo Metal Ind
WO2009034845A1 (fr) * 2007-09-14 2009-03-19 Toyota Jidosha Kabushiki Kaisha Procédé de production d'un séparateur pour pile à combustible
WO2010038544A1 (fr) * 2008-09-30 2010-04-08 新日本製鐵株式会社 Matériau en titane présentant une faible résistance de contact pour une utilisation dans un séparateur pour pile à combustible du type à polymère solide et procédé de fabrication du matériau en titane
WO2010140700A1 (fr) * 2009-06-01 2010-12-09 新日本製鐵株式会社 Matériau à base de titane sensible à la lumière visible et d'excellente activité photocatalytique, et procédé de fabrication de celui-ci
WO2011016465A1 (fr) * 2009-08-03 2011-02-10 新日本製鐵株式会社 Matériau en titane pour séparateur de cellule à combustible à polymère solide et procédé pour sa production
JP2018104808A (ja) * 2016-12-28 2018-07-05 新日鐵住金株式会社 チタン材、セパレータ、セル、および固体高分子形燃料電池

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0568537B2 (fr) * 1984-05-11 1993-09-29 Sumitomo Metal Ind
WO2009034845A1 (fr) * 2007-09-14 2009-03-19 Toyota Jidosha Kabushiki Kaisha Procédé de production d'un séparateur pour pile à combustible
WO2010038544A1 (fr) * 2008-09-30 2010-04-08 新日本製鐵株式会社 Matériau en titane présentant une faible résistance de contact pour une utilisation dans un séparateur pour pile à combustible du type à polymère solide et procédé de fabrication du matériau en titane
WO2010140700A1 (fr) * 2009-06-01 2010-12-09 新日本製鐵株式会社 Matériau à base de titane sensible à la lumière visible et d'excellente activité photocatalytique, et procédé de fabrication de celui-ci
WO2011016465A1 (fr) * 2009-08-03 2011-02-10 新日本製鐵株式会社 Matériau en titane pour séparateur de cellule à combustible à polymère solide et procédé pour sa production
JP2018104808A (ja) * 2016-12-28 2018-07-05 新日鐵住金株式会社 チタン材、セパレータ、セル、および固体高分子形燃料電池

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