WO2023155264A1 - 用于燃料电池双极板的铁素体不锈钢、表面粗糙度的调控方法、形成钝化膜的方法和用途 - Google Patents

用于燃料电池双极板的铁素体不锈钢、表面粗糙度的调控方法、形成钝化膜的方法和用途 Download PDF

Info

Publication number
WO2023155264A1
WO2023155264A1 PCT/CN2022/081922 CN2022081922W WO2023155264A1 WO 2023155264 A1 WO2023155264 A1 WO 2023155264A1 CN 2022081922 W CN2022081922 W CN 2022081922W WO 2023155264 A1 WO2023155264 A1 WO 2023155264A1
Authority
WO
WIPO (PCT)
Prior art keywords
stainless steel
passivation film
ferritic stainless
fuel cell
passivation
Prior art date
Application number
PCT/CN2022/081922
Other languages
English (en)
French (fr)
Inventor
卢华兴
席烨廷
杨运民
隗健
Original Assignee
山东产研先进材料研究院有限公司
国家电投集团氢能科技发展有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 山东产研先进材料研究院有限公司, 国家电投集团氢能科技发展有限公司 filed Critical 山东产研先进材料研究院有限公司
Priority to EP22729406.3A priority Critical patent/EP4253589A1/en
Priority to JP2022540711A priority patent/JP2024513272A/ja
Priority to KR1020227024855A priority patent/KR20230126179A/ko
Priority to CA3165412A priority patent/CA3165412A1/en
Publication of WO2023155264A1 publication Critical patent/WO2023155264A1/zh

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0236—Cold rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/34—Anodisation of metals or alloys not provided for in groups C25D11/04 - C25D11/32
    • 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
    • H01M8/021—Alloys based on iron
    • 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
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • 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

Definitions

  • the embodiment of the present application relates to the technical field of stainless steel production, for example, a ferritic stainless steel used for fuel cell bipolar plates, a method for controlling surface roughness, a method for forming a passivation film and its application.
  • a fuel cell is a device that directly converts the chemical energy of fuel into electrical energy
  • PEMFC proton exchange membrane fuel cell
  • the bipolar plate acts as a structural support for the membrane electrode in the fuel cell, separates hydrogen and oxygen, collects electrons, conducts heat, provides channels for hydrogen and oxygen, discharges water generated by the reaction, and provides coolant flow channels and other important roles.
  • metal bipolar plates can be made into thinner bipolar plates by stamping because of their high strength and toughness, and their applications are becoming more and more extensive.
  • the passivation film on the surface of stainless steel is an important corrosion-resistant functional layer, and its preparation process leads to the formation of a thin and discontinuous passivation film, resulting in poor corrosion resistance, uncontrollable growth and composition of the passivation film, resulting in conductive Performance and corrosion resistance are unstable.
  • titanium is currently the mainstream material for metal bipolar plates.
  • the present application provides a ferritic stainless steel used for a fuel cell bipolar plate, a method for controlling the surface roughness, a method for forming a passivation film and its application.
  • the embodiment of the present application provides a ferritic stainless steel used for a bipolar plate of a fuel cell.
  • the ferritic stainless steel includes:
  • O is preferably 0.02wt.% or less, and Sn is 0.1% or less;
  • the grain size of the ferritic stainless steel is grade 4-9, such as grade 4, grade 5, grade 6, grade 7 or grade 8, preferably grade 6-8. This can ensure that the stainless steel material has proper manufacturability (beneficial to processes such as rolling and heat treatment), and is beneficial to the processing and forming of the bipolar plate material while having a certain degree of economy.
  • C has the effect of solid solution strengthening. Its solubility in ferrite is very low, and the excess carbon is precipitated in the form of carbides. At the same time, C will form Cr carbonitrides with Cr, which will cause intergranular ferritic stainless steel. Corrosion and chromium depletion in grain boundaries affect the mechanical and welding properties of materials.
  • the C content is 0.03wt.% or less, such as 0.03wt.%, 0.02wt.% or 0.01wt.%, preferably the C content is 0.02wt.% or less.
  • N will form Cr carbonitrides with Cr, resulting in a Cr-depleted area and reducing the corrosion resistance of stainless steel.
  • the content of N is 0.02wt.% or less, such as 0.02wt.% or 0.01wt.%.
  • Si is an element useful for deoxidation. However, as the content increases, the processing performance of the material decreases. In the ferritic stainless steel of the present application, the Si content is below 0.4wt.%, such as 0.4wt.%, 0.35wt.%, 0.3wt.%, 0.25wt.%, 0.2wt.%, 0.15wt.%, 0.1wt.%, 0.08wt.%, 0.05wt.% or 0.03wt.%, etc.
  • Mn is an unavoidable element mixed in steel, in addition to a certain deoxidation effect, it can also improve the strength of steel.
  • MnS which is an impurity, acts as a starting point of corrosion and lowers corrosion resistance.
  • the content of Mn is below 0.5wt.%, such as 0.5wt.%, 0.47wt.%, 0.45wt.%, 0.4wt.%, 0.35wt.%, 0.3wt.%, 0.25wt.%, 0.2wt.%, 0.15wt.%, 0.1wt.%, 0.08wt.%, 0.05wt.% or 0.03wt.%, etc.
  • Cr is the basic element that determines the corrosion resistance of ferritic stainless steel. Chromium interacts with oxygen in the corrosive medium to form a thin oxide film on the surface of the steel, which can hinder the further corrosion of the steel matrix. However, the increase of chromium content will accelerate the formation and precipitation of ⁇ and ⁇ phases, resulting in a decrease in toughness and a significant increase in brittle transition temperature, which is not conducive to the processing in the process of manufacturing stainless steel.
  • the content of Cr is 16-23wt.%, such as 16wt.%, 16.5wt.%, 16.8wt.%, 17wt.%, 17.5wt.%, 18wt.%, 18.5wt.%. %, 19wt.%, 19.5wt.%, 20wt.%, 20.5wt.%, 21wt.%, 21.5wt.%, 22wt.%, 22.5wt.% or 23wt.%, etc.
  • Cu is an element that improves the corrosion resistance of stainless steel, and can improve the cold workability of the material.
  • the content of Cu is 0-2.0wt.%, such as 0wt.%, 0.05wt.%, 0.1wt.%, 0.2wt.%, 0.25wt.%, 0.3wt.%, 0.35wt.%, 0.4wt.%, 0.5wt.%, 0.55wt.%, 0.6wt.%, 0.7wt.%, 0.8wt.%, 1wt.%, 1.2wt.%, 1.3wt.%, 1.4 wt.%, 1.6wt.%, 1.8wt.% or 2wt.%, etc.
  • Mo is another main element that improves the corrosion resistance of stainless steel. Promote the passivation of Fe-Cr alloy, improve the corrosion resistance of steel in reducing medium, especially the anti-pitting corrosion, crevice corrosion and other local corrosion resistance in chloride solution. However, when the Mo content is high, the ferrite ⁇ phase and other brittle phases are prone to appear, which reduces the toughness of the steel and increases the strength, which is not conducive to the processing of the material. In the ferritic stainless steel of the present application, the content of Mo is 1.8-2.5wt.%, such as 1.8wt.%, 1.85wt.%, 1.9wt.%, 2.0wt.%, 2.1wt.%, 2.2wt.%. , 2.3wt.%, 2.4wt.% or 2.5wt.%, etc.
  • Ni is an element that improves the corrosion resistance of stainless steel, and at the same time acts to reduce contact resistance.
  • the content of Ni is 0.2-2.0wt.%, such as 0.2wt.%, 0.3wt.%, 0.4wt.%, 0.5wt.%, 0.6wt.%, 0.8wt.%. , 1.0wt.%, 1.1wt.%, 1.3wt.%, 1.4wt.%, 1.5wt.%, 1.7wt.%, 1.8wt.% or 2.0wt.%, etc.
  • Both Ti and Nb are preferentially combined with C and N to form carbonitrides, thereby suppressing the decrease in corrosion resistance due to the precipitation of Cr carbonitrides. However, if it contains too much, workability will fall.
  • the content of Ti is 0.1-0.5wt.%, such as 0.1wt.%, 0.2wt.%, 0.3wt.%, 0.4wt.% or 0.5wt.%.
  • the content of Nb is 0.005 ⁇ 0.5wt.%, such as 0.1wt.%, 0.2wt.%, 0.3wt.%, 0.4wt.% or 0.5wt.%, Nb is preferably 0.1 ⁇ 0.4wt.%.
  • the content of P is 0.02wt.% or less, such as 0.02wt.% or 0.01wt.%.
  • the content of S is 0.02wt.% or less, such as 0.02wt.% or 0.01wt.%, preferably 0.01wt.% or less.
  • 0 to 1 wt.% of V and/or 0 to 1 wt.% of W may be contained, respectively.
  • the content of both elements is preferably above 0.1 wt.%.
  • V and W will be combined with C in preference to Cr to improve the corrosion resistance of the material, and have a synergistic effect with Nb to a certain extent; at the same time, in order to maintain appropriate material processing properties, V and W are added , the amount of Nb added should be appropriately reduced.
  • rare earth metals preferably Ce or Y
  • the ferritic stainless steel of the present application has the characteristics of few types of alloy elements and low Cr content. Through the design of the types and contents of various elements, good corrosion resistance, electrical conductivity, and good elongation and deformation ability are obtained. At the same time Both economic and cost advantages.
  • the content of Ni is preferably 0.9-1.2wt.%, which further reduces the cost and still satisfies the above effects.
  • the ferritic stainless steel of the present application has the advantages of low cost and better formability.
  • the surface roughness of the ferritic stainless steel is between 100nm and 700nm. etc. If the roughness is too small, the interface contact resistance will increase significantly, the internal resistance of the fuel cell will increase, and it will not be able to achieve a good fit with the gas diffusion layer, so it is not suitable for application; if the roughness is too large, although the contact resistance is low, the material The corrosion resistance performance is obviously reduced, and cannot meet the requirements of the bipolar plate inside the fuel cell and in the acidic environment. It is preferably 100-600nm, and more preferably 200-500nm.
  • a passivation film is provided on the surface of the ferritic stainless steel, and the passivation film includes a p-type passivation film and an n-type passivation film.
  • the passivation film has advantages in performance. Its technical principle is as follows: the p-type passivation film can effectively prevent the solution from contacting with the substrate to cause corrosion, and the n-type passivation film can effectively prevent metal The ions are stripped out, thereby effectively reducing the adverse effects of metal ions on other core components of the fuel cell (such as proton exchange membranes, catalysts, etc.), and improving the performance and life of the fuel cell stack.
  • the p-type passivation film corresponds to the p-type semiconductor region
  • the n-type passivation film corresponds to the n-type semiconductor region
  • the p-type passivation film refers to a p-type semiconductor passivation film
  • the n-type passivation film refers to an n-type semiconductor passivation film
  • the positional relationship between the p-type passivation film and the n-type passivation film is not specifically limited, for example, the inner layer may be n-type and the outer layer may be p-type passivation film.
  • the inner layer refers to the side of the passive film close to the main material of the stainless steel, and the outer layer refers to the side close to the solution.
  • the molar ratio of chromium hydroxide and chromium oxide in the p-type passivation film is I p [Cr(OH) 3 /Cr 2 O 3 ], I p [Cr(OH) 3 /Cr 2 O 3 ] is not less than 10, such as 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 23 or 25, etc., preferably not less than 15.
  • Excellent corrosion resistance can be obtained by optimizing the molar ratio of chromium hydroxide and chromium oxide in the p-type passivation film, the higher the ratio, the higher the hydroxide ratio, and the better the corrosion resistance.
  • the molar ratio of chromium hydroxide and chromium oxide in the n-type passivation film is In [Cr(OH) 3 /Cr 2 O 3 ], In [Cr(OH) 3 /Cr 2 O 3 ] is not more than 10, such as 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0.5, etc., preferably less than 5.
  • Excellent conductivity can be obtained by optimizing the molar ratio of chromium hydroxide and chromium oxide in the n-type passivation film, the lower the ratio, the higher the oxide ratio, the better the conductivity.
  • I p [Cr(OH) 3 /Cr 2 O 3 ]/I n [Cr(OH) 3 /Cr 2 O 3 ] ⁇ 3 the overall performance of the passivation film cannot be guaranteed.
  • I p [Cr(OH) 3 /Cr 2 O 3 ]/I n [Cr(OH) 3 /Cr 2 O 3 ] is referred to as I p / In for short.
  • the passivation film has a thickness of 5-20nm, such as 5nm, 6nm, 8nm, 10nm, 12nm, 13nm, 15nm, 16nm, 18nm, 19nm or 20nm, preferably 10-15nm. If the passivation film is too thin (less than 5nm), the corrosion resistance will be poor, and if the passivation film is too thick (greater than 20nm), the conductivity will be poor. In this preferred thickness range of 10-15nm, good corrosion resistance can be better taken into account. Corrosive and conductive.
  • the thickness of the p-type passivation film is t p
  • the thickness of the n-type passivation film is t n , 0.2 ⁇ t p /t n ⁇ 0.6, t p /t n such as 0.25, 0.3, 0.35 , 0.4, 0.45, 0.5 or 0.55 etc.
  • the excellent interfacial contact resistance can be better guaranteed.
  • the inner layer is an n-type passivation film
  • the outer layer is a p-type passivation film, and it satisfies: 0.2 ⁇ t p /t n ⁇ 0.6.
  • the structure of the passivation film is the inner n-type (better conductivity) and the outer p-type (better corrosion resistance), and the p-type passivation film is thinner and the n-type passivation film is thicker, This structure determines its good corrosion resistance and electrical conductivity.
  • the embodiment of the present application provides a method for regulating the surface roughness of stainless steel, the regulating method comprising:
  • a stainless steel main material is provided, and the stainless steel main material is electrolyzed in an acid solution.
  • the polarization voltage satisfies the following formula (I):
  • E is the polarization voltage
  • the unit of the polarization voltage is V
  • D is the grain size of the main material of stainless steel
  • the unit of the grain size is micron
  • pH is the pH value of the initial acid solution.
  • the control method of the present application utilizes the method of electrolysis to control the surface roughness of the main material of stainless steel, which has the advantage of controllable surface roughness, and can adjust the surface roughness of stainless steel according to the characteristics of membrane electrodes and gas diffusion in proton exchange membrane fuel cells,
  • the bipolar plate and related components can be well bonded to reduce the contact resistance of the battery system, which is more suitable for industrial application characteristics.
  • the control method can be based on the ferritic stainless steel described in the first aspect.
  • the control method can also be based on other stainless steel materials in the field.
  • the ferritic stainless steel described in the first aspect refers to: the main material of stainless steel (such as a stainless steel plate) is made of the ferritic stainless steel described in the first aspect, such as by smelting, hot rolling and cold rolled.
  • the polarization voltage is 5-15V, such as 5V, 6V, 8V, 9V, 10V, 12V, 13V or 15V.
  • the electrolysis time is 10 to 300s, such as 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 60s, 65s, 70s, 75s, 80s, 85s, 90s, 100s, 120s, 130s, 140s, 150s, 160s, 170s, 180s, 200s, 220s, 230s, 240s, 260s, 280s, or 300s, etc., preferably 20 to 120s.
  • the electrolysis temperature is 25-70°C, such as 25°C, 27°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C or 70°C, etc., preferably It is 25 ⁇ 40°C.
  • the acid solution used in the electrolysis process is sulfuric acid, or a mixed acid solution of sulfuric acid and hydrohalic acid.
  • sulfuric acid and hydrohalic acid Through the combination of sulfuric acid and hydrohalic acid, the roughness preparation time can be shortened and the roughness can be appropriately increased.
  • hydrohalic acid is abbreviated as HX acid, wherein X is a halogen, and X can be F, Cl, Br or I, for example.
  • the hydrohalic acid is at least one of hydrofluoric acid, hydrochloric acid, hydrobromic acid, and hydroiodic acid, preferably hydrochloric acid and/or hydrofluoric acid.
  • the concentration of the sulfuric acid is 0.1-14 mol/L, such as 0.1 mol/L, 0.3 mol/L, 0.5 mol/L, 0.8 mol/L, 1 mol/L, 1.5 mol/L, 1.7 mol/L, 2mol/L, 2.2mol/L, 2.5mol/L, 2.8mol/L, 3mol/L, 3.5mol/L, 3.8mol/L, 4mol/L, 4.5mol/L, 5mol/L, 5.5mol/L , 6mol/L, 6.5mol/L, 7mol/L, 7.5mol/L, 8mol/L, 8.5mol/L, 9mol/L, 9.5mol/L, 10mol/L, 11mol/L, 12mol/L, 13mol /L or 14 mol/L, etc., preferably 0.1 to 7 mol/L.
  • the concentration of hydrohalic acid is 0-3 mol/L and does not contain 0, such as 0.05 mol/L, 0.1 mol/L, 0.2 mol/L, 0.25 mol /L, 0.3mol/L, 0.4mol/L, 0.5mol/L, 0.7mol/L, 1mol/L, 1.5mol/L, 1.7mol/L, 1.9mol/L, 2mol/L, 2.2mol/L , 2.4mol/L, 2.5mol/L, 2.8mol/L or 3mol/L, etc., preferably no more than 0.5mol/L.
  • the embodiment of the present application provides a method for forming a passivation film on the surface of stainless steel.
  • the passivation film is prepared by electrochemical passivation, and the method includes the following steps:
  • the stainless steel main material is provided, and a three-electrode system is adopted.
  • the stainless steel main material, counter electrode and reference electrode are placed in an electrochemical passivation solution for constant potential polarization to form a passivation film on the surface of the stainless steel main material.
  • the main material of stainless steel is the sample to be treated, and the other two electrodes are the counter electrode and the reference electrode.
  • the reference electrode is between the sample to be treated and the counter electrode.
  • the present application forms a passivation film on the surface of stainless steel through an electrochemical passivation method, and the obtained passivation film has excellent performance, is dense and has good continuity, and can achieve the purpose of enhancing corrosion resistance and reducing contact resistance.
  • the selection and method of the passivation solution are highly environmentally friendly, and can ensure excellent contact resistance under the condition of ultra-low concentration or no hydrofluoric acid (meeting the US DOE standard).
  • the electrochemical passivation method of the present application can control the composition, structure and thickness of the passivation film, and the control of the passivation film can be realized through the process of electrochemical passivation based on specific material composition design.
  • the main material of the stainless steel involved can be based on the ferritic stainless steel described in the first aspect, or based on the stainless steel after the roughness has been regulated in the second aspect, or can be Based on other stainless steel materials in the field.
  • the preparation method of the main material of stainless steel is the prior art, and those skilled in the art can refer to the relevant technology for preparation. As an example and not limitative, it can be prepared according to the following method:
  • the ingot is opened to a certain thickness (such as 80-120 mm) to obtain a stainless steel plate, and then hot-rolled.
  • the heating and holding temperature is 1150-1200 ° C, and the holding time is 1.5 ⁇ 2.0h, the starting rolling temperature is controlled at 1100 ⁇ 1150°C, after 8 ⁇ 10 passes rolling to a certain thickness (such as 2 ⁇ 3mm), the final rolling temperature is controlled above 800°C.
  • annealing treatment is carried out.
  • the annealing temperature is 950 ° C ⁇ 1050 ° C.
  • the holding time depends on the size of the hot rolled coil.
  • pickling treatment is carried out. After 8 to 10 passes of cold rolling to the desired thickness, then continuous annealing for 1 to 3 minutes.
  • the method of the present application can ensure excellent corrosion resistance and electrical conductivity by preparing controllable roughness on the stainless steel surface and then forming a passivation film.
  • the electrochemical passivation solution is a nitric acid solution with a concentration of 0.05-10 mol/L, such as 0.5 mol/L, 1 mol/L, 1.5 mol/L, 2 mol/L, 2.5 mol/L, 3 mol/L, 3.5mol/L, 4mol/L, 4.5mol/L, 5mol/L, 5.5mol/L, 6mol/L, 6.5mol/L, 7mol/L, 7.5mol/L, 8mol/L, 8.5mol/L, 9 mol/L or 10 mol/L, etc.
  • the concentration of the nitric acid solution is preferably 1.5-5 mol/L.
  • the temperature of the electrochemical passivation is 20-85°C, such as 20°C, 25°C, 30°C, 33°C, 35°C, 38°C, 40°C, 45°C, 50°C, 55°C, 60°C , 65°C, 70°C, 75°C, 80°C or 85°C, etc., preferably 35 to 65°C.
  • the anode voltage of the electrochemical passivation is not lower than 0.45V, such as 0.5V, 0.6V, 0.7V, 0.8V, 0.9V, 1.0V, 1.1V, 1.2V, 1.3V or 1.4V, etc. , preferably 0.8-1.2V.
  • the electrochemical passivation time is 5-120min, such as 5min, 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min, 65min, 70min, 80min, 90min, 100min , 110 min or 120 min, etc., preferably 50 to 90 min.
  • the embodiment of the present application provides the use of the ferritic stainless steel as described in the first aspect, and the ferritic stainless steel is used for a bipolar plate of a fuel cell.
  • the ferritic stainless steel in the embodiment of the present application has the characteristics of few types of alloying elements and low Cr content. Through the design of the types and contents of each element, good corrosion resistance, electrical conductivity, and good elongation are obtained and deformability, while being economical and cost-effective. Wherein, the content of Ni can be as low as 0.2-0.5, which further reduces the cost and still satisfies the above effects.
  • the control method of the embodiment of the present application uses electrolysis to control the surface roughness of the main stainless steel material, which has the advantage of controllable surface roughness, and can be adjusted according to the characteristics of the membrane electrode and gas diffusion in the proton exchange membrane fuel cell
  • the surface roughness of the stainless steel enables the bipolar plate to fit well with related components, thereby reducing the contact resistance of the battery system, which is more suitable for industrial application characteristics.
  • the embodiment of the present application forms a passivation film on the surface of stainless steel by means of electrochemical passivation, and the obtained passivation film has excellent performance, the passivation film is dense and has good continuity, and can achieve the effect of enhancing corrosion resistance and reducing contact resistance. Purpose. Moreover, the selection and method of the passivation solution are highly environmentally friendly, and can ensure excellent contact resistance under the condition of ultra-low concentration or no hydrofluoric acid (meeting the US DOE standard).
  • FIG. 1 is a graph showing the relationship between the roughness of stainless steel and the interface contact resistance in an embodiment of the present application, in which samples 1-6 respectively correspond to embodiments 16-21.
  • Fig. 2 and Fig. 3 are the XPS diagrams of the passivation film of stainless steel in one embodiment of the present application.
  • Fig. 4 is an M-S curve diagram of a passivation film of stainless steel in an embodiment of the present application.
  • Fig. 5 is a diagram of carrier concentration of p-type and n-type passivation films of stainless steel in an embodiment of the present application.
  • Fig. 6 is a cross-sectional topography diagram of a passivation film of stainless steel in an embodiment of the present application.
  • Cr is the basic element that determines the corrosion resistance of ferritic stainless steel. Chromium interacts with oxygen in the corrosive medium to form a thin oxide film on the surface of the steel, which can hinder the further corrosion of the steel matrix. However, the increase of chromium content will accelerate the formation and precipitation of ⁇ and ⁇ phases, resulting in a decrease in toughness and a significant increase in brittle transition temperature, which is not conducive to the processing in the process of manufacturing stainless steel.
  • Mo is another main element that improves the corrosion resistance of stainless steel. Promote the passivation of Fe-Cr alloy, improve the corrosion resistance of steel in reducing medium, especially the anti-pitting corrosion, crevice corrosion and other local corrosion resistance in chloride solution. However, when the Mo content is high, the ferrite ⁇ phase and other brittle phases are prone to appear, which reduces the toughness of the steel and increases the strength, which is not conducive to the processing of the material.
  • C has the effect of solid solution strengthening. Its solubility in ferrite is very low, and excess carbon is precipitated in the form of carbides, which will cause intergranular corrosion and chromium depletion in grain boundaries of ferritic stainless steel, affecting the mechanical and welding properties of the material.
  • Si is an element useful for deoxidation. However, as the content increases, the processing performance of the material decreases.
  • Mn is an unavoidable element mixed in steel, in addition to a certain deoxidation effect, it can also improve the strength of steel.
  • MnS which is an impurity, acts as a starting point of corrosion and lowers corrosion resistance.
  • N and C will form Cr carbonitrides with Cr, resulting in a Cr-depleted area and reducing the corrosion resistance of stainless steel.
  • Both Ti and Nb are preferentially combined with C and N to form carbonitrides, thereby suppressing the decrease in corrosion resistance due to the precipitation of Cr carbonitrides. However, if it contains too much, workability will fall.
  • Cu is an element that improves the corrosion resistance of stainless steel, and can improve the cold workability of the material.
  • Ni is an element that improves the corrosion resistance of stainless steel, and at the same time acts to reduce contact resistance.
  • the balance is Fe and unavoidable impurities.
  • 0 to 1 wt.% of V and/or 0 to 1 wt.% of W may be contained, respectively.
  • the content of both elements is preferably above 0.1 wt.%.
  • rare earth metals preferably Ce or Y
  • Example 1 For the stainless steel material of Example 1, the elongation after fracture was detected at room temperature according to the requirements of GB/T 228.1-2010. The sample was prepared according to the standard sheet tensile standard and tested, and the elongation after fracture of the sample was 33.5%.
  • the above-mentioned stainless steel materials are subjected to surface roughness treatment in turn, and the materials are prepared with different surface roughnesses.
  • the specific treatment method is: use concentrated sulfuric acid and deionized water to prepare a sulfuric acid solution, and the above-mentioned stainless steel materials are finally processed.
  • the material whose length and width are both 20 mm is put into sulfuric acid solution for surface roughness treatment under different parameters. See Table 2 for roughness preparation conditions.
  • stainless steel has a lower interface contact resistance, and the material can be used in fuel cells after proper optimization.
  • the roughness is preferably between 100 and 700nm. Preferably it is 200 to 500 nm. Materials outside the preferred range have higher interfacial contact resistance (Examples 19, 20, and 21), making it difficult to apply them in fuel cells.
  • the obtained steel plate was electrochemically passivated in 1.6mol/L HNO 3 solution at 40°C with an anode voltage of 1.1V for 1h.
  • the sample was rinsed with deionized water and dried with nitrogen cold air, and placed in a dry environment (air) at room temperature for 24 hours.
  • the samples are then tested, specifically:
  • X-ray photoelectron spectroscopy is used to analyze the depth of the passivation film and perform narrow-spectrum scanning.
  • the X-ray source is Al K ⁇ micro-focused monochromatic source, which is scanned by CAE scanning mode.
  • the narrow-spectrum scanning pass energy is 30-50eV, step size 0.05-0.1eV; use argon ion etching for depth profiling, each etching depth is 1nm, 1nm, 1nm, 1nm, 2nm, 2nm, 2nm, 5nm, 5nm.
  • the passivation film is a p-type semiconductor passivation film
  • the hydrogen of Fe and Cr in the passivation film When the content of the oxide is lower than the content of the oxides of Fe and Cr in the passivation film, it is judged as an n-type semiconductor passivation film.
  • the thickness t p of the p-type semiconductor and the thickness t n of the n-type semiconductor in the passivation film can be determined, as well as the ratio of chromium hydroxide to chromium oxide in the p-type passivation film and n-type passivation film, so as to obtain t p /t n and I p /I n .
  • Figures 2 and 3 are XPS diagrams of the passivation film of stainless steel in Example 1, and Figure 2 shows the contents of hydroxides and oxides of Fe and Cr in the passivation film. It can be seen from the figure that the thickness of the p-type semiconductor passivation film is about 5nm, while the thickness of the n-type semiconductor passivation film is between 10-15nm. The passivation film thickness ratio t p /t n is 0.33-0.56, and the corrected t p /t n is 0.55.
  • the bar graphs represent the contents of Cr hydroxides and Cr oxides in different thickness regions of the passivation film, and the graphs represent the corresponding ratios of hydroxides and oxides.
  • the ratio of hydroxide to oxide is above 10, most of which are above 15 (the average value of 15 is taken); while the hydrogen of Cr in the n-type passivation film
  • the ratio of oxides to oxides is around 2-5, most of them are 2-3 (taking the average value of 2.5). Therefore, it can be judged that I p /I n is 7.
  • the contact resistance can be less than or equal to 8m ⁇ cm 2
  • the thickness ratio of p-type and n-type semiconductors is between 0.2 and 0.6
  • I p [Cr(OH) 3 /Cr 2 O 3 ]/I n [Cr(OH) 3 /Cr 2 O 3 ] is greater than 4 surface passivation film
  • the current density is less than 3 ⁇ A ⁇ cm -2
  • the interface contact resistance is less than 8m ⁇ cm 2 , indicating that the passivation film has excellent protection and conductivity.
  • the concentration of hydrohalic acid in the range of 0-3mol/L is conducive to improving I p /I n , keeping t p /t n in an appropriate range, and reducing the interface Contact resistance and corrosion current density.
  • the concentration of sulfuric acid in the range of 0.1-7mol/L is conducive to improving Ip / In , keeping tp / tn in an appropriate range, and reducing interface contact resistance and Corrosion current density.
  • Example 10 Through the comparison between Example 10 and Example 11, and the comparison between Example 14 and Example 15, it can be seen that in the roughness preparation conditions, the polarization voltage in the range of 5-15V is conducive to improving I p /I n and making t p /t n in the appropriate range, reduce the interface contact resistance and corrosion current density.
  • the reason for the decline in the performance of the passivation film in Example 13 may be that in the roughness preparation conditions, the electrolysis time is too long, resulting in poor thickness ratio and composition of the p-type passivation film and n-type passivation film .
  • Example 1 The difference with Example 1 is that the electrochemical passivation treatment is carried out with different parameters, and the analysis and evaluation are carried out according to the same method as in Example 1, the electrochemical passivation conditions and test results of Example 1 and Examples 22-30 are shown in Table 5.
  • Example 30 in Table 5 is a bare sample, and on the basis of Example 1, no electrochemical passivation was performed.
  • the performance of the passivation film can be further improved by adjusting the parameter conditions of the electrochemical passivation such as nitric acid concentration, temperature, potential and passivation time within the specified range.
  • the test results of the stainless steel sample in Example 1 after serving in the fuel cell environment for a period of time show that the passivation film can not only reduce the contact resistance of the stainless steel interface to below 8m ⁇ cm 2 , but also reduce the corrosion current density of the stainless steel. Maintained at a low level, it exhibits good corrosion resistance and electrical conductivity.
  • Mott-Schottky Carry out Mott-Schottky (Mott-Schottky, M-S) curve test to embodiment 1, embodiment 25, embodiment 29 and embodiment 30, determine the carrier concentration of passivation film, judge electrochemical passivation treatment and Effect of voltage on passivation film properties.
  • the specific M-S curve test method is:
  • the MS curve test uses an electrochemical workstation with a test range of -1 to 1V and a test step size of 25mV/step.
  • the slope of the straight line segment of the p-type passivation film and the n-type passivation film is obtained by fitting, and then the carrier concentration corresponding to the p-type and n-type is calculated according to the MS model, and the performance of the passivation film is determined by the carrier concentration.
  • Fig. 4 is embodiment 1 (electrochemical passivation voltage 1.1V), embodiment 25 (electrochemical passivation voltage 0.8V), embodiment 29 (electrochemical passivation voltage 0.6V) and embodiment 30 (not carrying out electrochemical passivation
  • the M-S curve diagram of the passivation film of stainless steel as can be seen from Figure 4, the sample without electrochemical passivation, the p-type semiconductor region is not obvious, and the passivation film mainly shows the characteristics of n-type semiconductor region; 0.6V constant potential electrode After polarization, the slopes of the straight line segments of the p-type and n-type semiconductor regions both increased, but the p-type region did not increase significantly; after 0.8V and 1.1V constant potential polarization, the slopes of the p-type semiconductor region and n-type semiconductor region first The phase slope increases significantly. On the whole, with the increase of the constant potential polarization voltage, the slope of the p-type semiconductor line segment is obvious and gradually increases. The slope of the straight line segment
  • Fig. 5 is embodiment 1 (electrochemical passivation voltage 1.1V), embodiment 25 (electrochemical passivation voltage 0.8V), embodiment 29 (electrochemical passivation voltage 0.6V) and embodiment 30 (no electrochemical passivation) the M-S carrier concentration figure of the passivation film of stainless steel, as can be seen from Figure 5, the carrier concentration of the p-type semiconductor region of the passivation film on the sample surface after electrochemical passivation gradually decreases (relative to The reduction of the non-electrochemical passivation is nearly 4 times), and the decrease of the carrier concentration indicates the increase of the density of the passivation film, indicating that its protection performance becomes better.
  • the passivation film can not only ensure the improvement of corrosion resistance, but also not significantly increase the contact resistance.
  • the passivation film of the stainless steel of embodiment 1 is carried out cross-sectional morphology characterization, and concrete characterization method is: utilize transmission electron microscope (TEM) to characterize the sample section cut by focused ion beam, obtain passivation film cross-sectional topography ( In order to protect the passivation film from being damaged during the preparation of the focused ion beam sample, a layer of carbon film was first deposited on the outermost layer), the result is shown in Figure 6, the uppermost part is the deposited C layer, and the middle part is the passivation film , the bottom part is a stainless steel substrate. It can be seen from the figure that the overall passivation film is continuous, dense and uniform without obvious defects, and the thickness is about 12-20nm. The outer layer of the passivation film is uneven because the outermost passivation film has a dynamic growth and dissolution process in the acid solution, and the surface of the passivation film in the acid solution is usually uneven.
  • TEM transmission electron microscope
  • Example 6 The difference from Example 1 lies in the steel grade, whether surface roughness treatment is performed, and whether electrochemical passivation treatment is performed.
  • the results are shown in Table 6.
  • the surface roughness treatment can be directly carried out after step (1) without electrochemical passivation treatment; the electrochemical passivation treatment can also be directly carried out after step (1) without surface roughness treatment; Surface roughness treatment and electrochemical passivation treatment can also be carried out successively after step (1);
  • Example 1 The difference with Example 1 is the steel grade, whether surface roughness treatment is carried out, and whether electrochemical passivation treatment is carried out.
  • the results are shown in Table 6.
  • the surface roughness treatment can be directly carried out after step (1) without electrochemical passivation treatment; the electrochemical passivation treatment can also be directly carried out after step (1) without surface roughness treatment; Surface roughness treatment and electrochemical passivation treatment can also be carried out successively after step (1);
  • the roughness treatment conditions are as follows: at room temperature (25° C.), the sample is polarized at 10 V for 50 s in a 3 mol/L H 2 SO 4 solution.
  • the conditions of the chemical passivation treatment are as follows: the steel plate obtained after the above-mentioned roughness treatment is subjected to electrochemical passivation at an anode voltage of 1.1V for 1 hour in a 1.6mol/L HNO 3 solution at 40°C.
  • the stainless steel is subjected to roughness treatment in turn and then a passivation film is provided.
  • the passivation film on the surface of the stainless steel has good performance, the thickness ratio of p-type and n-type semiconductors is between 0.2 and 0.6, and I p [Cr(OH) 3 /Cr 2 O 3 ]/I n [Cr(OH) 3 /Cr 2 O 3 ] is greater than 4; and after running for a certain period of time, the interface contact resistance is less than 8m ⁇ cm 2 , and the current density is less than 3 ⁇ A/cm 2 , showing good performance.
  • the present application illustrates the detailed method of the present application through the above-mentioned examples, but the present application is not limited to the above-mentioned detailed method, that is, it does not mean that the application must rely on the above-mentioned detailed method to be implemented.
  • Those skilled in the art should understand that any improvement to the present application, the equivalent replacement of each raw material of the product of the present application, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present application.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Sustainable Development (AREA)
  • Manufacturing & Machinery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Energy (AREA)
  • General Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Chemical Treatment Of Metals (AREA)
  • Fuel Cell (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

本文公布了一种用于燃料电池双极板的铁素体不锈钢、表面粗糙度的调控方法、形成钝化膜的方法和用途。所述铁素体不锈钢包括C 0.03wt.％以下、N 0.02wt.％以下、Si 0.4wt.％以下、Mn 0.5wt.％以下、Cr 16～23wt.％、Cu 0～2.0wt.％、Mo 1.8～2.5wt.％、Ni 0.2～2.0wt.％、Ti 0.1～0.5wt.％、Nb 0.005～0.5wt.％、P 0.02wt.％以下、S 0.02wt.％以下，余量为Fe和无法避免而含有的其他元素，所述铁素体不锈钢的晶粒度为4～9级。其具有良好的耐腐蚀性能、导电性能，以及良好的延伸率和变形能力，同时兼具经济性和成本优势。

Description

用于燃料电池双极板的铁素体不锈钢、表面粗糙度的调控方法、形成钝化膜的方法和用途 技术领域
本申请实施例涉及不锈钢生产技术领域，例如一种用于燃料电池双极板的铁素体不锈钢、表面粗糙度的调控方法、形成钝化膜的方法和用途。
背景技术
燃料电池是一种把燃料所具有的化学能直接转换成电能的装置，质子交换膜燃料电池(PEMFC)是燃料电池的一种。PEMFC因其高发电效率和对环境的无污染性，发展到现在已受到全世界重视和快速发展。双极板作为燃料电池的核心部件，起到了在燃料电池中的膜电极结构支撑、分隔氢气和氧气、收集电子、传导热量、提供氢气和氧气通道、排出反应生成的水、提供冷却液流道等重要作用。随着对燃料电池高体积功率密度要求的提升，金属双极板因其材料具有较高的强度和韧性，可采用冲压的方式制成较薄的双极板，应用愈加广泛。
但是，金属双极板在氢燃料电池环境中耐腐蚀性能差、界面接触电阻高，一直是较为棘手的问题，业界迫切需要一种耐蚀性强、导电性好、成本低廉的金属材料，以匹配产业快速发展带来的大规模需求。2017年韩国学者公开了一种具有优异的接触电阻的用于聚合物燃料电池隔板的不锈钢及其制造方法(KR:013918/2017；CN:110199047B/2017)，其不锈钢产品目前已经用于现代燃料电池汽车生产，其导电性和耐腐蚀性符合美国能源部制定的标准。2010年日本学者公开了一种用于JFE的一种耐腐蚀性优良的燃料电池用不锈钢及其制造方法(CN:102471916/2010；JP：062739/2010)，相关材料将应用在燃料电池巴士上。
随着近年来行业的迅速发展，对产品一致性要求随之提高，而相关的关于铁素体不锈钢双极板的制备技术方案的主要问题在于因成分设计问题导致的变形能力差，导致在双极板加工过程中的成形难度大，双极板变形还会导致密封性差等问题。同时，合金化元素较多导致的成本问题。另一方面，不锈钢表面钝化膜作为重要的耐蚀功能层，其制备工艺问题导致形成的钝化膜较薄且不连续，导致耐蚀性能差，钝化膜生长及成分不可控，导致导电性能与耐蚀性能不稳定。此外，金属双极板目前主流材料除了不锈钢还有钛，而钛作为双极板材 料变形能力相对较差，冲压难度较大，且成本比不锈钢高很多，这些都影响到极板的一致性、耐蚀性与经济性等关键问题，亟待解决。
发明内容
以下是对本文详细描述的主题的概述。本概述并非是为了限制权利要求的保护范围。
本申请提供一种用于燃料电池双极板的铁素体不锈钢、表面粗糙度的调控方法、形成钝化膜的方法和用途。
第一方面，本申请实施例提供一种用于燃料电池双极板的铁素体不锈钢，以所述铁素体不锈钢的质量为100wt.％计，所述铁素体不锈钢包括：
Figure PCTCN2022081922-appb-000001
余量为Fe和无法避免而含有的其他元素，在不可避免的杂质中，优选O为0.02wt.％以下，Sn为0.1％以下；
所述铁素体不锈钢的晶粒度为4～9级，例如4级、5级、6级、7级或8级等，优选为6～8级。这样可以保证不锈钢材料具有适当的工艺性(有利于轧制、热处理等工艺)，有利于双极板材料加工成形的同时兼具一定的经济性。
C具有固溶强化的效果，其在铁素体中的溶解度很低，过剩的碳以碳化物的形式析出，同时C会和Cr形成Cr的碳氮化物，会造成铁素体不锈钢的晶间腐蚀和晶界贫铬，影响材料的力学和焊接等性能。本申请的铁素体不锈钢中，C 的含量为0.03wt.％以下，例如0.03wt.％、0.02wt.％或0.01wt.％等，优选C的含量为0.02wt.％以下。
N会和Cr形成Cr的碳氮化物，产生贫Cr区而使不锈钢的耐腐蚀性降低。本申请的铁素体不锈钢中，N的含量为0.02wt.％以下，例如0.02wt.％或0.01wt.％等。
Si是对脱氧有用的元素。但是，随含量增加，则材料加工性能降低。本申请的铁素体不锈钢中，Si的含量为0.4wt.％以下，例如0.4wt.％、0.35wt.％、0.3wt.％、0.25wt.％、0.2wt.％、0.15wt.％、0.1wt.％、0.08wt.％、0.05wt.％或0.03wt.％等。
Mn是钢中不可避免混入的元素，除一定脱氧作用外，还可提高钢的强度。但作为杂质的MnS会成为腐蚀的起点，使耐腐蚀性降低。本申请的铁素体不锈钢中，Mn的含量为0.5wt.％以下，例如0.5wt.％、0.47wt.％、0.45wt.％、0.4wt.％、0.35wt.％、0.3wt.％、0.25wt.％、0.2wt.％、0.15wt.％、0.1wt.％、0.08wt.％、0.05wt.％或0.03wt.％等。
Cr是决定铁素体不锈钢的耐腐蚀性的根本元素，铬与腐蚀介质中的氧作用，在钢外表构成一层很薄的氧化膜，可阻碍钢的基体进一步腐蚀。但铬含量的增加会加速α和σ相的形成和沉淀，使其韧性下降和脆性转变温度显著上升，不利于制造不锈钢过程中的加工。本申请的铁素体不锈钢中，Cr的含量为16～23wt.％，例如16wt.％、16.5wt.％、16.8wt.％、17wt.％、17.5wt.％、18wt.％、18.5wt.％、19wt.％、19.5wt.％、20wt.％、20.5wt.％、21wt.％、21.5wt.％、22wt.％、22.5wt.％或23wt.％等。
Cu是提高不锈钢的耐腐蚀性的元素，并且可以改善材料的冷加工性能。本申请的铁素体不锈钢中，Cu的含量为0～2.0wt.％，例如0wt.％、0.05wt.％、0.1wt.％、0.2wt.％、0.25wt.％、0.3wt.％、0.35wt.％、0.4wt.％、0.5wt.％、0.55wt.％、0.6wt.％、0.7wt.％、0.8wt.％、1wt.％、1.2wt.％、1.3wt.％、1.4wt.％、1.6wt.％、1.8wt.％或2wt.％等。
Mo是提高不锈钢的耐腐蚀性的另一主要元素。促进Fe-Cr合金的钝化，提高钢在还原性介质中的耐蚀性，特别是在氯化物溶液中的抗点蚀、缝隙腐蚀等抗局部腐蚀性能。但Mo含量较高时，易出现铁素体σ相和其它脆性相，使钢的韧性降低强度增加，不利于材料的加工。本申请的铁素体不锈钢中，Mo的含量 为1.8～2.5wt.％，例如1.8wt.％、1.85wt.％、1.9wt.％、2.0wt.％、2.1wt.％、2.2wt.％、2.3wt.％、2.4wt.％或2.5wt.％等。
Ni是提高不锈钢的耐腐蚀性的元素，同时可以起到降低接触电阻的作用。本申请的铁素体不锈钢中，Ni的含量为0.2～2.0wt.％，例如0.2wt.％、0.3wt.％、0.4wt.％、0.5wt.％、0.6wt.％、0.8wt.％、1.0wt.％、1.1wt.％、1.3wt.％、1.4wt.％、1.5wt.％、1.7wt.％、1.8wt.％或2.0wt.％等。
Ti和Nb都是优先与C、N结合生成碳氮化物，从而抑制由于Cr碳氮化物的析出而导致的耐腐蚀性降低。但是，如果含过高量，则加工性降低。本申请的铁素体不锈钢中，Ti的含量为0.1～0.5wt.％，例如0.1wt.％、0.2wt.％、0.3wt.％、0.4wt.％或0.5wt.％等。本申请的铁素体不锈钢中，Nb的含量为0.005～0.5wt.％，例如0.1wt.％、0.2wt.％、0.3wt.％、0.4wt.％或0.5wt.％等，Nb优选0.1～0.4wt.％。
本申请的铁素体不锈钢中，P的含量为0.02wt.％以下，例如0.02wt.％或0.01wt.％等。
本申请的铁素体不锈钢中，S的含量为0.02wt.％以下，例如0.02wt.％或0.01wt.％等，优选为0.01wt.％以下。
另外，除上述以外，以耐腐蚀性的改善为目的，可以分别含有0～1wt.％的V和/或0～1wt.％的W。为了得到该效果，两种元素优选含量均在0.1wt.％以上。
作为本申请一个优选的技术方案，V和W会优先于Cr与C结合，提高材料的耐腐蚀性，一定程度上与Nb有协同作用；同时，为了维持合适的材料加工性能，加入V和W时，Nb的加入量要适当降低。
以提高热加工性的为目的，也可以含有0.0002～1wt.％的稀土金属，优选Ce或Y。为了得到该效果，优选含有0.0005wt.％以上。
本申请的铁素体不锈钢具有合金元素种类少、Cr含量较低的特点，通过各元素种类和含量的设计，获得了良好的耐腐蚀性能、导电性能，以及良好的延伸率和变形能力，同时兼具经济性和成本优势。其中，Ni的含量优选0.9～1.2wt.％，进一步降低成本，且仍满足上述效果。
本申请的铁素体不锈钢相较于其他金属材料双极板(如钛双极板)具有成本低的优势，且成形加工性能更好的优点。
优选地，所述铁素体不锈钢的表面粗糙度在100～700nm之间，粗糙度例如100nm、150nm、170nm、200nm、230nm、260nm、300nm、325nm、350nm、 380nm、400nm、435nm、460nm或500nm等，粗糙度过小，界面接触电阻显著增加，燃料电池内阻增大，且无法与气体扩散层实现较好贴合，故不适合应用；粗糙度过大，接触电阻虽然较低，但是材料耐蚀性能明显降低，不能满足燃料电池内部和酸性环境中对双极板的要求，优选为100～600nm，进一步优选为200～500nm。
作为本申请所述铁素体不锈钢的优选技术方案，所述铁素体不锈钢的表面设置有钝化膜，所述钝化膜包括p型钝化膜和n型钝化膜。该钝化膜作为重要的耐腐蚀、导电功能层，在性能上具有优势，其技术原理如下：p型钝化膜可有效防止溶液与基体接触而发生腐蚀，n型钝化膜可有效防止金属离子溶出，从而有效降低金属离子对燃料电池其他核心部件(如质子交换膜、催化剂等)的不良影响，提高燃料电池电堆性能与寿命。
本申请中，p型钝化膜对应p型半导体区域，n型钝化膜对应n型半导体区域。
本申请中，p型钝化膜指的是p型半导体型的钝化膜，n型钝化膜指的是n型半导体型的钝化膜。
本申请中，对p型钝化膜和n型钝化膜的位置关系不作具体限定，例如可以是内层为n型外层为p型的钝化膜。内层指的是钝化膜靠近不锈钢主材的一侧，外层指的是靠近溶液的一侧。
优选地，所述p型钝化膜内的氢氧化铬和氧化铬的摩尔比为I p[Cr(OH) 3/Cr 2O 3]，I p[Cr(OH) 3/Cr 2O 3]不小于10，例如10、11、12、13、14、15、16、17、18、20、23或25等，优选不小于15。通过优化p型钝化膜内的氢氧化铬和氧化铬的摩尔比可获得优异的耐腐蚀性，该比例越高，氢氧化物比例高，耐蚀性越好。
优选地，所述n型钝化膜内的氢氧化铬和氧化铬的摩尔比为I n[Cr(OH) 3/Cr 2O 3]，I n[Cr(OH) 3/Cr 2O 3]不大于10，例如10、9、8、7、6、5、4、3、2、1或0.5等，优选小于5。通过优化n型钝化膜内的氢氧化铬和氧化铬的摩尔比可获得优异的导电性，该比例越低，氧化物比例高，导电性越好。
优选地，I p[Cr(OH) 3/Cr 2O 3]/I n[Cr(OH) 3/Cr 2O 3]>3，优选I p[Cr(OH) 3/Cr 2O 3]/I n[Cr(OH) 3/Cr 2O 3]≥4。例如3.5、4、5、6、7、8、9或10等。若I p[Cr(OH) 3/Cr 2O 3]/I n[Cr(OH) 3/Cr 2O 3]≤3，则钝化膜综合性能无法保证。
本申请中，I p[Cr(OH) 3/Cr 2O 3]/I n[Cr(OH) 3/Cr 2O 3]简称为I p/I n。
优选地，所述钝化膜的厚度为5～20nm，例如5nm、6nm、8nm、10nm、12nm、13nm、15nm、16nm、18nm、19nm或20nm等，优选10～15nm。钝化膜太薄(小于5nm)则耐蚀性不好，钝化膜太厚(大于20nm)则导电性不好，在此优选的厚度范围10～15nm内，可以更好地兼顾良好的耐腐蚀性和导电性。
优选地，所述p型钝化膜的厚度为t p，所述n型钝化膜的厚度为t n，0.2<t p/t n<0.6，t p/t n例如0.25、0.3、0.35、0.4、0.45、0.5或0.55等。在此条件下可以更好地保证优异的界面接触电阻。
优选地，所述钝化膜中，内层为n型钝化膜，外层为p型钝化膜，而且满足：0.2<t p/t n<0.6。
此优选技术方案中，钝化膜结构为内层n型(导电性较好)外层p型(耐蚀性较好)，且p型钝化膜较薄而n型钝化膜较厚，此种结构决定了其兼具良好的耐蚀性与导电性。
第二方面，本申请实施例提供一种不锈钢的表面粗糙度的调控方法，所述调控方法包括：
提供不锈钢主材，将所述不锈钢主材在酸溶液中进行电解，所述电解的过程中，极化电压满足下述公式(Ⅰ)：
E≥lg D+12+pH       (Ⅰ)
其中，E为极化电压，极化电压的单位为V，D为不锈钢主材的晶粒尺寸，晶粒尺寸的单位为微米，pH为初始酸液的pH值。
本申请的调控方法利用电解的方法调控不锈钢主材的表面粗糙度，具有表面粗糙度可控的优点，可以根据质子交换膜燃料电池中膜电极及气体扩散的特点针对性调整不锈钢表面粗糙度，使双极板与相关部件实现良好贴合从而降低电池体系的接触电阻，更加适合行业应用特点。
本申请的方法中，若E不满足公式(Ⅰ)，则可能导致粗糙度无明显变化，无法到达到最优粗糙度以匹配气体扩散层，从而对燃料电池电堆性能产生不良影响。
该调控方法可以以第一方面所述的铁素体不锈钢为基础。该调控方法也可以以本领域其他的不锈钢材料为基础。
其中，“以第一方面所述的铁素体不锈钢为基础”指的是：不锈钢主材(例 如不锈钢板)的由第一方面所述的铁素体不锈钢制成，例如通过冶炼、热轧及冷轧制成。
优选地，所述极化电压为5～15V，例如5V、6V、8V、9V、10V、12V、13V或15V等。
优选地，所述电解的时间为10～300s，例如10s、15s、20s、25s、30s、35s、40s、45s、50s、60s、65s、70s、75s、80s、85s、90s、100s、120s、130s、140s、150s、160s、170s、180s、200s、220s、230s、240s、260s、280s或300s等，优选为20～120s。
优选地，所述电解的温度为25～70℃，例如25℃、27℃、30℃、35℃、40℃、45℃、50℃、55℃、60℃、65℃或70℃等，优选为25～40℃。
优选地，所述电解的过程中使用的酸液为硫酸，或者硫酸与氢卤酸的混合酸液。通过硫酸与氢卤酸的配合，可以缩短粗糙度制备时间，适当增大粗糙度。
本申请中，氢卤酸简写为HX酸，其中，X为卤素，X例如可以是F、Cl、Br或I。
优选地，所述氢卤酸为氢氟酸、盐酸、氢溴酸、氢碘酸中的至少一种，优选为盐酸和/或氢氟酸。
优选地，所述硫酸的浓度为0.1～14mol/L，例如0.1mol/L、0.3mol/L、0.5mol/L、0.8mol/L、1mol/L、1.5mol/L、1.7mol/L、2mol/L、2.2mol/L、2.5mol/L、2.8mol/L、3mol/L、3.5mol/L、3.8mol/L、4mol/L、4.5mol/L、5mol/L、5.5mol/L、6mol/L、6.5mol/L、7mol/L、7.5mol/L、8mol/L、8.5mol/L、9mol/L、9.5mol/L、10mol/L、11mol/L、12mol/L、13mol/L或14mol/L等，优选为0.1～7mol/L。
优选地，所述硫酸与氢卤酸的混合酸液中，氢卤酸的浓度为0～3mol/L且不含0，例如0.05mol/L、0.1mol/L、0.2mol/L、0.25mol/L、0.3mol/L、0.4mol/L、0.5mol/L、0.7mol/L、1mol/L、1.5mol/L、1.7mol/L、1.9mol/L、2mol/L、2.2mol/L、2.4mol/L、2.5mol/L、2.8mol/L或3mol/L等，优选不超过0.5mol/L。
第三方面，本申请实施例提供一种在不锈钢表面形成钝化膜的方法，采用电化学钝化的方法制备钝化膜，所述方法包括以下步骤：
提供不锈钢主材，采用三电极体系，将所述不锈钢主材、对电极和参比电极置于电化学钝化液中，进行恒电位极化，在不锈钢主材的表面形成钝化膜。
三电极体系中，不锈钢主材为待处理样品，另外两个电极分别为对电极和 参比电极。一般，参比电极在待处理样品和对电极之间。
本申请通过电化学钝化的方法在不锈钢表面形成钝化膜，得到的钝化膜性能优异，钝化膜致密且连续性好，可达到增强耐腐蚀性、降低接触电阻的目的。而且，钝化溶液选择和方法上环保性强，可实现在超低浓度或无氢氟酸条件下确保优异的接触电阻(满足美国DOE标准)。
本申请的电化学钝化方法可以实现对钝化膜成分、结构和厚度的控制，对于钝化膜控制，可以基于特定的材料成分设计，通过电化学钝化的工艺而实现。
在不锈钢表面形成钝化膜的方法中，涉及到的不锈钢主材可以以第一方面所述的铁素体不锈钢为基础，也可以以第二方面调控完粗糙度以后的不锈钢为基础，还可以以本领域其他的不锈钢材料为基础。
本申请中，不锈钢主材的制备方法为现有技术，本领域技术人员可参照相关技术进行制备，示例性而非限制性地，可以按照下述方法进行制备：
按照上述第一方面的铁素体不锈钢的组成制备铸锭，铸锭经开坯至一定厚度(例如80～120mm)得到不锈钢板，而后热轧，加热保温温度为1150～1200℃，保温时间1.5～2.0h，开轧温度控制在1100～1150℃，经8～10道次轧至一定厚度(例如2～3mm)，终轧温度控制在800℃以上。
热轧后进行退火处理，退火温度950℃～1050℃，保温时间视热轧板卷尺寸而定，热轧后进行酸洗处理。经8～10道次冷轧至所需厚度，然后进行连续退火，时间1～3min。
本申请的方法通过在不锈钢表面制备可控的粗糙度，再形成钝化膜，可以确保优异的耐蚀性能和导电性能。
优选地，所述电化学钝化液为浓度在0.05～10mol/L的硝酸溶液，例如0.5mol/L、1mol/L、1.5mol/L、2mol/L、2.5mol/L、3mol/L、3.5mol/L、4mol/L、4.5mol/L、5mol/L、5.5mol/L、6mol/L、6.5mol/L、7mol/L、7.5mol/L、8mol/L、8.5mol/L、9mol/L或10mol/L等，所述硝酸溶液的浓度优选为1.5～5mol/L。
优选地，所述电化学钝化的温度为20～85℃，例如20℃、25℃、30℃、33℃、35℃、38℃、40℃、45℃、50℃、55℃、60℃、65℃、70℃、75℃、80℃或85℃等，优选为35～65℃。
优选地，所述电化学钝化的阳极电压为不低于0.45V，例如0.5V、0.6V、0.7V、0.8V、0.9V、1.0V、1.1V、1.2V、1.3V或1.4V等，优选为0.8～1.2V。
优选地，所述电化学钝化的时间为5～120min，例如5min、10min、15min、20min、25min、30min、35min、40min、45min、50min、55min、60min、65min、70min、80min、90min、100min、110min或120min等，优选为50～90min。
第四方面，本申请实施例提供一种如第一方面所述的铁素体不锈钢的用途，所述铁素体不锈钢用于燃料电池双极板。
与相关技术相比，本申请具有如下有益效果：
(1)本申请实施例的铁素体不锈钢具有合金元素种类少、Cr含量较低的特点，通过各元素种类和含量的设计，获得了良好的耐腐蚀性能、导电性能，以及良好的延伸率和变形能力，同时兼具经济性和成本优势。其中，Ni的含量可以低至0.2～0.5，进一步降低成本，且仍满足上述效果。
(2)本申请实施例的调控方法利用电解的方法调控不锈钢主材的表面粗糙度，具有表面粗糙度可控的优点，可以根据质子交换膜燃料电池中膜电极及气体扩散的特点针对性调整不锈钢表面粗糙度，使双极板与相关部件实现良好贴合从而降低电池体系的接触电阻，更加适合行业应用特点。
(3)本申请实施例通过电化学钝化的方法在不锈钢表面形成钝化膜，得到的钝化膜性能优异，钝化膜致密且连续性好，可达到增强耐腐蚀性、降低接触电阻的目的。而且，钝化溶液选择和方法上环保性强，可实现在超低浓度或无氢氟酸条件下确保优异的接触电阻(满足美国DOE标准)。
在阅读并理解了附图和详细描述后，可以明白其他方面。
附图说明
附图用来提供对本文技术方案的进一步理解，并且构成说明书的一部分，与本申请的实施例一起用于解释本文的技术方案，并不构成对本文技术方案的限制。
图1是本申请一个实施例中不锈钢的粗糙度与界面接触电阻关系图，其中样品1-6分别依次对应实施例16-21。
图2和图3是本申请一个实施例中不锈钢的钝化膜的XPS图。
图4是本申请一个实施例中不锈钢的钝化膜的M-S曲线图。
图5是本申请一个实施例中不锈钢的p型和n型钝化膜的载流子浓度图。
图6是本申请一个实施例中不锈钢的钝化膜截面形貌图。
具体实施方式
下面结合附图并通过具体实施方式来进一步说明本申请的技术方案。
炼钢采用的材料的化学组成(质量百分比，wt.％)如表1所示。
表1
Figure PCTCN2022081922-appb-000002
铁素体不锈钢中各元素作用如下：
Cr是决定铁素体不锈钢的耐腐蚀性的根本元素，铬与腐蚀介质中的氧作用，在钢外表构成一层很薄的氧化膜，可阻碍钢的基体进一步腐蚀。但铬含量的增加会加速α和σ相的形成和沉淀，使其韧性下降和脆性转变温度显著上升，不利于制造不锈钢过程中的加工。
Mo是提高不锈钢的耐腐蚀性的另一主要元素。促进Fe-Cr合金的钝化，提高钢在还原性介质中的耐蚀性，特别是在氯化物溶液中的抗点蚀、缝隙腐蚀等抗局部腐蚀性能。但Mo含量较高时，就易出现铁素体σ相和其它脆性相，使钢的韧性降低强度增加，不利于材料的加工。
C具有固溶强化的效果。其在铁素体中的溶解度很低，过剩的碳以碳化物的形式析出，同时会造成铁素体不锈钢的晶间腐蚀和晶界贫铬，影响材料的力学和焊接等性能。
Si是对脱氧有用的元素。但是，随含量增加，则材料加工性能降低。
Mn是钢中不可避免混入的元素，除一定脱氧作用外，还可提高钢的强度。 但作为杂质的MnS会成为腐蚀的起点，使耐腐蚀性降低。
N和C会和Cr形成Cr的碳氮化物，产生贫Cr区而使不锈钢的耐腐蚀性降低。
Ti和Nb都是优先与C、N结合生成碳氮化物，从而抑制由于Cr碳氮化物的析出而导致的耐腐蚀性降低。但是，如果含过高量，则加工性降低。
Cu是提高不锈钢的耐腐蚀性的元素，并且可以改善材料的冷加工性能。
Ni是提高不锈钢的耐腐蚀性的元素，同时可以起到降低接触电阻的作用。
余量为Fe和不可避免的杂质。
另外，除上述以外，以耐腐蚀性的改善为目的，可以分别含有0～1wt.％的V和/或0～1wt.％的W。为了得到该效果，两种元素优选含量均在0.1wt.％以上。
以提高热加工性的为目的，也可以含有0.0002～1wt.％的稀土金属，优选Ce或Y。为了得到该效果，优选含有0.0005wt.％以上。
实施例1-21
按照上述表1所示不同钢号的铁素体不锈钢制备铸锭，其中，各个实施例的铸锭和不同钢号的铁素体不锈钢的对应关系参见表2，铸锭经开坯至100mm得到不锈钢板，而后热轧，加热保温温度为1200℃，保温时间2h，开轧温度控制在1100℃，经8道次轧至3mm，终轧温度控制在800℃。热轧后进行退火处理，退火温度1050℃，保温时间视热轧板卷尺寸而定，热轧后进行酸洗处理。之后，取出空冷，再进行冷轧，制成所需厚度的箔材，再进行950℃保温2min的退火处理，得到最终箔材样品，也即不锈钢材料。
对实施例1的不锈钢材料，按GB/T 228.1-2010要求检测室温下断后伸长率，试样按照标准制备片状拉伸标准并进行测试，得到试样断后伸长率为33.5％。
对上述的不锈钢材料依次进行表面粗糙度处理，将材料制备出不同的表面粗糙度，具体的处理方法为：采用浓硫酸和去离子水配成硫酸溶液，将如上所述的不锈钢材料，最终加工的长、宽均为20mm的材料，放入硫酸溶液中进行不同参数下的表面粗糙度处理，粗糙度制备条件参见表2。
表2
Figure PCTCN2022081922-appb-000003
Figure PCTCN2022081922-appb-000004
对实施例16-21的不锈钢材料进行粗糙度处理后，取样，用丙酮清洁材料表面并用氮气吹干后，利用表面轮廓仪对不锈钢进行表面粗糙度的测试并记录，利用界面接触电阻测量仪测试并记录材料在150N/cm 2下的界面接触电阻值，结果如表3和图1所示。
表3
Figure PCTCN2022081922-appb-000005
由表3和图1可知，在一定的表面粗糙度范围内，不锈钢材料具有较低的 界面接触电阻，材料经适当优化可以在燃料电池中得以应用，优选粗糙度在100～700nm之间，进一步优选为200～500nm。在优选范围外的材料的界面接触电阻较高(实施例19、20、21)，应用在燃料电池中困难较大。粗糙度过小，界面接触电阻显著增加，燃料电池内阻增大，且无法与气体扩散层实现较好贴合，故不适合应用；粗糙度过大，接触电阻虽然较低，但是材料耐蚀性能明显降低，不能满足燃料电池内部及酸性环境中对双极板的要求。在上述粗糙度处理后(其中实施例16-21经过了表面粗糙度和界面接触电阻的测试)，继续对实施例1-21的钢板进行电化学钝化处理，具体的处理方法为：
将所得到的钢板在40℃的1.6mol/L HNO 3溶液中，以1.1V的阳极电压进行电化学钝化1h。
在上述电化学钝化处理后，对样品进行去离子水冲洗并用氮气冷风吹干，在室温干燥环境(空气)中放置24h。然后将样品进行测试，具体地：
(一)按照下述方法确定t p/t n和I p/I n，结果示于表4中：
(Ⅰ)用X射线光电子能谱(XPS)对钝化膜进行深度剖析并进行窄谱扫描，X射线源为Al Kα微聚焦单色源，采用CAE扫描模式进行扫描，窄谱扫描通能为30～50eV，步长0.05～0.1eV；采用氩离子刻蚀进行深度剖析，每次刻蚀深度分别为1nm、1nm、1nm、1nm、2nm、2nm、2nm、2nm、5nm、5nm。
(Ⅱ)利用软件对所测结果进行处理，按照每个物相对应的峰面积来表示其含量。因为不锈钢钝化膜中主要组成为Fe和Cr的氢氧化物以及氧化物，因此XPS测试主要分析钝化膜中Fe和Cr的物相及其氢氧化物和氧化物的含量。当钝化膜Fe和Cr的氢氧化物的含量高于钝化膜中Fe和Cr的氧化物的含量时判定钝化膜为p型半导体钝化膜，当钝化膜中Fe和Cr的氢氧化物的含量低于钝化膜中Fe和Cr的氧化物的含量时判定为n型半导体钝化膜。基于此，可确定钝化膜中p型半导体的厚度t p和n型半导体的厚度t n，以及p型钝化膜和n型钝化膜中氢氧化铬和氧化铬之比，从而得到t p/t n和I p/I n。
图2和图3是实施例1中不锈钢的钝化膜的XPS图，图2示出了钝化膜中Fe和Cr的氢氧化物和氧化物的含量。从图中可以看到，p型半导体钝化膜厚度为5nm左右，而n型半导体钝化膜厚度在10-15nm之间。两者钝化膜厚度比值t p/t n在0.33-0.56，修正后的t p/t n为0.55。图3中，柱状图分别表示Cr的氢氧化物和Cr的氧化物在钝化膜中不同厚度区域的含量，而曲线图表示的是对应的氢 氧化物和氧化物的比。结合图2可以看出，在p型钝化膜中，氢氧化物与氧化物的比在10以上，大部分在15以上(取15平均值)；而n型钝化膜中的Cr的氢氧化物和氧化物的比在2-5左右，大部分在2-3(取2.5平均值)。因此可以判断I p/I n为7。
(二)进行模拟燃料电池工作环境下的服役性能测试：进行300h耐久测试，温度80℃，pH＝3的硫酸溶液，电位0.84V(vs.SHE)，记录腐蚀电流密度数值并测量材料表面在150N/cm 2下的界面接触电阻值，结果示于表4中。
表4
Figure PCTCN2022081922-appb-000006
由上述的表4可知，在同时实施粗糙度处理和电化学钝化处理的情况下， 可以得到接触电阻小于等于8mΩ·cm 2、p型和n型半导体厚度比在0.2～0.6之间，且I p[Cr(OH) 3/Cr 2O 3]/I n[Cr(OH) 3/Cr 2O 3]大于4的表面钝化膜，电流密度小于3μA·cm -2、界面接触电阻小于8mΩ·cm 2，说明钝化膜具有优异的保护性和导电性。
同时，通过表4可以看出，在电化学钝化处理条件不变的基础上，通过改变粗糙度制备条件可以改变不锈钢表面状态，进而最终改善所制备钝化膜的性能：
通过实施例2-3可知，在粗糙度制备条件中，氢卤酸浓度在0-3mol/L范围内有利于提高I p/I n、使t p/t n在合适的范围内，降低界面接触电阻和腐蚀电流密度。
通过实施例2-5可知，粗糙度制备条件中，硫酸浓度在0.1～7mol/L范围内有利于提高I p/I n、使t p/t n在合适的范围内，降低界面接触电阻和腐蚀电流密度。
通过实施例6-9可知，粗糙度制备条件中，电解的温度在25～70℃范围内有利于提高I p/I n，降低界面接触电阻和腐蚀电流密度。
通过实施例10与实施例11的对比，以及实施例14与实施例15的对比可知，粗糙度制备条件中，极化电压在5～15V范围内有利于提高I p/I n、使t p/t n在合适的范围内，降低界面接触电阻和腐蚀电流密度。
综合实施例10-13，实施例13钝化膜性能下降的原因可能是粗糙度制备条件中，电解时间过长，导致了p型钝化膜和n型钝化膜的厚度比以及组成不佳。
实施例22-30
与实施例1的区别在于，以不同的参数进行电化学钝化处理，按照与实施例1相同的方法进行分析和评价，实施例1以及实施例22-30的电化学钝化条件以及测试结果示于表5中。
表5
Figure PCTCN2022081922-appb-000007
Figure PCTCN2022081922-appb-000008
注：表5中实施例30为裸样，在实施例1的基础上，未进行电化学钝化。
由表4可知，通过调整电化学钝化的参数条件例如硝酸浓度、温度、电位以及钝化时间在规定范围，可以进一步提升钝化膜的性能，。其中，实施例1的不锈钢样品经过一段时间在燃料电池环境中服役后的测试结果可知，该钝化膜不仅可使不锈钢界面接触电阻降低到8mΩ·cm 2以下，还可以使不锈钢的腐蚀电流密度保持在较低水平，展现出良好的耐蚀性与导电性。
对实施例1、实施例25、实施例29以及实施例30进行莫特-肖特基(Mott-Schottky，M-S)曲线测试，确定钝化膜的载流子浓度，判断电化学钝化处理以及电压对钝化膜性能的影响。
具体的M-S曲线测试方法为：
将样品在80℃的pH＝3的硫酸溶液中进行M-S曲线测试，其中，为了增加硫酸溶液导电性，在溶液中加入0.1mol/L的Na 2SO 4。M-S曲线测试采用的是电化学工作站，测试范围-1～1V，测试步长为25mV/step。拟合获得p型钝化膜和n型钝化膜的直线段的斜率，然后根据M-S模型计算p型和n型对应的载流子浓度，通过载流子浓度来确定钝化膜的性能。
图4是实施例1(电化学钝化电压1.1V)、实施例25电化学钝化电压0.8V)、实施例29(电化学钝化电压0.6V)以及实施例30(未进行电化学钝化)的不锈钢的钝化膜的M-S曲线图，由图4可知，未电化学钝化的样品，p型半导体区域不明显，钝化膜主要表现出n型半导体区域特征；0.6V恒电位极化后，p型和n型半导体区域的直线段斜率均有所增加，但p型区域增加不明显；而0.8V和1.1V恒电位极化后，p型半导体区域和n型半导体区域的先行阶段斜率明显增加。整体来看，随着恒电位极化电压增加，p型半导体直线段斜率明显且逐渐增加。n型半导体区域直线段斜率也逐渐增加。
图5是实施例1(电化学钝化电压1.1V)、实施例25(电化学钝化电压0.8V)、实施例29(电化学钝化电压0.6V)以及实施例30(未进行电化学钝化)的不锈钢的钝化膜的M-S载流子浓度图，由图5可知，电化学钝化后的样品表面钝化膜的p型半导体区域载流子浓度逐渐降低(1.1V时相对于未电化学钝化降低了近4倍)，载流子浓度的降低表示钝化膜致密性的增加，说明其保护性能变好。电化学钝化后n型半导体区域载流子浓度有所降低(1.1V时降低不到2倍)，这一方面说明n型半导体钝化膜区域的保护性增加，另一方面说明其导电性没有显著降低。因此，整体来看，钝化膜既能保证耐蚀性能的提高，又不会显著提高接触电阻。
同时，由上述的表4、图4和图5可知，通过调整电化学钝化处理的参数可以改变钝化膜的组成，优化钝化膜的性能。例如，可以在电化学钝化处理中施加不同的电压，调控钝化膜的特性(参见图4和图5)，使得随电位升高，钝化膜中p型半导体和n型半导体厚度比值t p/t n逐渐增加，进而提高不锈钢在燃料电池电堆中的服役性能，即上述参数的调整可以改变钝化膜的组成，优化钝化膜的性能，最终提高不锈钢双极板应用在燃料电池中的适应性。
对实施例1的不锈钢的钝化膜进行截面形貌表征，具体的表征方法为：利用透射电子显微(TEM)对聚焦离子束切割的样品截面进行表征，获得钝化膜截面形貌图(为保护钝化膜在聚焦离子束样品制备过程中不被破坏，首先在最表层沉积一层碳膜)，结果如图6所示，最上部分是所沉积的C层，中间部分是钝化膜，最下部分是不锈钢基体。由图可知，钝化膜整体连续、致密且均匀，无明显缺陷，厚度在12～20nm左右。钝化膜外层不平整，是因为最外层钝化膜在酸溶液中存在动态生长和溶解过程，酸溶液中钝化膜表面通常均不平整。
实施例31-37
与实施例1的区别在于，钢号、是否进行表面粗糙度处理、是否进行电化学钝化处理，结果示于表6中。具体地，可以在步骤(1)之后直接进行表面粗糙度处理，而不进行电化学钝化处理；也可以在步骤(1)之后直接进行电化学钝化处理，而不进行表面粗糙度处理；还可以在步骤(1)之后依次进行表面粗糙度处理和电化学钝化处理；
实施例38-45
与实施例1的区别在于，钢号、是否进行表面粗糙度处理、是否进行电化 学钝化处理，结果示于表6中。具体地，可以在步骤(1)之后直接进行表面粗糙度处理，而不进行电化学钝化处理；也可以在步骤(1)之后直接进行电化学钝化处理，而不进行表面粗糙度处理；还可以在步骤(1)之后依次进行表面粗糙度处理和电化学钝化处理；
其中，粗糙度处理的条件为：室温(25℃)，在3mol/L的H 2SO 4溶液中以10V电压对样品极化50s。
化学钝化处理的条件为：将上述粗糙度处理后所得到的钢板在40℃的1.6mol/L HNO 3溶液中，以1.1V的阳极电压进行电化学钝化1h。
表6
Figure PCTCN2022081922-appb-000009
由上述的表6可知，在粗糙度处理后设置钝化膜，可以进一步增强保护作 用并提升导电性，进一步提升性能。
同时，依次对不锈钢进行粗糙度处理然后设置钝化膜，不锈钢表面钝化膜均具有良好的性能，p型和n型半导体厚度比在0.2～0.6之间，且I p[Cr(OH) 3/Cr 2O 3]/I n[Cr(OH) 3/Cr 2O 3]大于4；且运行一定时间后其界面接触电阻小于8mΩ·cm 2，电流密度小于3μA/cm 2，性能良好。此外，不管粗糙度处理后未设置钝化膜或者未进行粗糙度处理直接设置钝化膜，表面钝化膜的性能相比于既未进行粗糙度处理又未进行钝化膜设置的样品均有大幅提升，后续长期服役测试也显示其界面接触电阻降低、电流密度降低。
申请人声明，本申请通过上述实施例来说明本申请的详细方法，但本申请并不局限于上述详细方法，即不意味着本申请必须依赖上述详细方法才能实施。所属技术领域的技术人员应该明了，对本申请的任何改进，对本申请产品各原料的等效替换及辅助成分的添加、具体方式的选择等，均落在本申请的保护范围和公开范围之内。

Claims (16)

  1. 一种用于燃料电池双极板的铁素体不锈钢，其中，以所述铁素体不锈钢的质量为100wt.％计，所述铁素体不锈钢包括：
    Figure PCTCN2022081922-appb-100001
    余量为Fe和无法避免而含有的其他元素；
    所述铁素体不锈钢的晶粒度为4～9级。
  2. 根据权利要求1所述的用于燃料电池双极板的铁素体不锈钢，其中，所述铁素体不锈钢的晶粒度为6～8级。
  3. 根据权利要求1所述的用于燃料电池双极板的铁素体不锈钢，其中，所述铁素体不锈钢还含有0～1wt.％以下的V和/或0～1wt.％的W。
  4. 根据权利要求1所述的用于燃料电池双极板的铁素体不锈钢，其中，所述铁素体不锈钢还含有0.0002～1wt.％的稀土金属。
  5. 根据权利要求1或2所述的用于燃料电池双极板的铁素体不锈钢，其中，所述铁素体不锈钢的表面粗糙度在100～700nm之间，优选为100～600nm，进一步优选为200～500nm。
  6. 根据权利要求1-5任一项所述的用于燃料电池双极板的铁素体不锈钢，其中，所述铁素体不锈钢的表面设置有钝化膜，所述钝化膜包括p型钝化膜和n型钝化膜；
    优选地，所述p型钝化膜内的氢氧化铬和氧化铬的摩尔比为I p[Cr(OH) 3/Cr 2O 3]，I p[Cr(OH) 3/Cr 2O 3]不小于10，优选不小于15；
    优选地，所述n型钝化膜内的氢氧化铬和氧化铬的摩尔比为I n[Cr(OH) 3/Cr 2O 3]，I n[Cr(OH) 3/Cr 2O 3]不大于10，优选小于5。
    优选地，I p[Cr(OH) 3/Cr 2O 3]/I n[Cr(OH) 3/Cr 2O 3]>3，优选I p[Cr(OH) 3/Cr 2O 3]/I n[Cr(OH) 3/Cr 2O 3]≥4。
  7. 根据权利要求6所述的用于燃料电池双极板的铁素体不锈钢，其中，所述钝化膜的厚度为5～20nm，优选10～15nm；
    优选地，所述p型钝化膜的厚度为t p，所述n型钝化膜的厚度为t n，0.2<t p/t n<0.6；
    优选地，所述钝化膜中，内层为n型钝化膜，外层为p型钝化膜，而且满足：0.2<t p/t n<0.6。
  8. 一种不锈钢的表面粗糙度的调控方法，其包括：
    提供不锈钢主材，将所述不锈钢主材在酸溶液中进行电解，所述电解的过程中，极化电压满足下述公式(Ⅰ)：
    E≥lg D+12+pH  (Ⅰ)
    其中，E为极化电压，极化电压的单位为V，D为不锈钢主材的晶粒尺寸，晶粒尺寸的单位为微米，pH为初始酸液的pH值。
  9. 根据权利要求8所述的不锈钢的表面粗糙度的调控方法，其中，所述极化电压为5～15V。
  10. 根据权利要求8所述的不锈钢的表面粗糙度的调控方法，其中，所述电解的时间为10～300s，优选为20～120s。
  11. 根据权利要求8所述的不锈钢的表面粗糙度的调控方法，其中，所述电解的温度为25～70℃，优选为25～40℃；
    优选地，所述电解的过程中使用的酸液为硫酸，或者硫酸与氢卤酸的混合酸液；
    优选地，所述氢卤酸为氢氟酸、盐酸、氢溴酸、氢碘酸中的至少一种，优选为盐酸和/或氢氟酸；
    优选地，所述硫酸的浓度为0.1～14mol/L，优选为0.1～7mol/L；
    优选地，所述硫酸与氢卤酸的混合酸液中，氢卤酸的浓度为0～3mol/L且不含0，优选不超过0.5mol/L。
  12. 一种在不锈钢表面形成钝化膜的方法，其中，采用电化学钝化的方法 制备钝化膜，所述方法包括以下步骤：
    提供不锈钢主材，采用三电极体系，将所述不锈钢主材、对电极和参比电极置于电化学钝化液中，进行恒电位极化，在不锈钢主材的表面形成钝化膜。
  13. 根据权利要求12所述的方法，其中，所述电化学钝化液为浓度在0.05～10mol/L的硝酸溶液，所述硝酸溶液的浓度优选为1.5～5mol/L。
  14. 根据权利要求12所述的方法，其中，所述电化学钝化的温度为20～85℃，优选为35～65℃。
  15. 根据权利要求12所述的方法，其中，所述电化学钝化的阳极电压为不低于0.45V，优选为0.8～1.2V；
    优选地，所述电化学钝化的时间为5～120min，优选为50～90min。
  16. 一种如权利要求1-7任一项所述的铁素体不锈钢的用途，其中，所述铁素体不锈钢用于燃料电池双极板。
PCT/CN2022/081922 2022-02-21 2022-03-21 用于燃料电池双极板的铁素体不锈钢、表面粗糙度的调控方法、形成钝化膜的方法和用途 WO2023155264A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP22729406.3A EP4253589A1 (en) 2022-02-21 2022-03-21 Ferritic stainless steel for bipolar plate of fuel cell, surface roughness adjustment and control method, method for forming passivation film, and use
JP2022540711A JP2024513272A (ja) 2022-02-21 2022-03-21 燃料電池のバイポーラプレート用のフェライト系ステンレス鋼、表面粗さの調整制御方法、不動態化膜の形成方法および使用
KR1020227024855A KR20230126179A (ko) 2022-02-21 2022-03-21 연료전지 양극판용 페라이트계 스테인리스강, 표면 거칠기의 제어방법, 패시베이션 막의 형성 방법 및 용도
CA3165412A CA3165412A1 (en) 2022-02-21 2022-03-21 Ferritic stainless steel used for bipolar plates of fuel cells, controlling method of surface roughness, method of forming passivation films, and use

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202210155650.8 2022-02-21
CN202210155650.8A CN114574759B (zh) 2022-02-21 2022-02-21 用于燃料电池双极板的铁素体不锈钢、形成钝化膜的方法和用途

Publications (1)

Publication Number Publication Date
WO2023155264A1 true WO2023155264A1 (zh) 2023-08-24

Family

ID=81774104

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/081922 WO2023155264A1 (zh) 2022-02-21 2022-03-21 用于燃料电池双极板的铁素体不锈钢、表面粗糙度的调控方法、形成钝化膜的方法和用途

Country Status (2)

Country Link
CN (2) CN115896896A (zh)
WO (1) WO2023155264A1 (zh)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115612918A (zh) * 2022-07-25 2023-01-17 宁波宝新不锈钢有限公司 一种具有高温性能的铁素体不锈钢及其制备方法
CN115044839B (zh) * 2022-08-12 2022-11-15 浦项(张家港)不锈钢股份有限公司 一种具有耐高温氧化表面的不锈钢带、制造方法及应用

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010062739A (ja) 2008-09-02 2010-03-18 Fujitsu Ltd 増幅回路および光変調器用ドライバ回路
CN102272343A (zh) * 2008-12-29 2011-12-07 Posco公司 用于聚合物燃料电池隔板的不锈钢及其制造方法
CN102471916A (zh) 2009-07-23 2012-05-23 杰富意钢铁株式会社 耐腐蚀性优良的燃料电池用不锈钢及其制造方法
JP2012201951A (ja) * 2011-03-25 2012-10-22 Nisshin Steel Co Ltd 粗大粗面化ステンレス鋼板および色素増感太陽電池の製造法
CN102925950A (zh) * 2011-06-30 2013-02-13 通用电气公司 用于粗化金属表面的方法及由其制造的物品
CN104746123A (zh) * 2015-04-11 2015-07-01 常州大学 一种在316l不锈钢表面进行电化学改性的技术方法
KR20170013918A (ko) 2014-06-06 2017-02-07 얼라인 테크널러지, 인크. 렌즈 포지셔닝 시스템
CN108368612A (zh) * 2015-12-17 2018-08-03 株式会社Posco 具有改善的亲水特性和耐腐蚀性的用于聚合物电解质膜燃料电池的隔板的不锈钢及其制造方法
JP2019070187A (ja) * 2017-10-11 2019-05-09 新日鐵住金株式会社 ステンレス鋼材、構成部材、セルおよび燃料電池スタック
CN110199047A (zh) 2016-12-22 2019-09-03 株式会社Posco 具有优异的接触电阻的用于聚合物燃料电池隔板的不锈钢及其制造方法
CN111519229A (zh) * 2020-04-09 2020-08-11 大连理工大学 一种质子交换膜燃料电池不锈钢双极板的电化学表面改性方法
JP2021004384A (ja) * 2019-06-25 2021-01-14 日鉄ステンレス株式会社 ステンレス鋼

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5768641B2 (ja) * 2010-10-08 2015-08-26 Ｊｆｅスチール株式会社 耐食性および電気伝導性に優れたフェライト系ステンレス鋼およびその製造方法、ならびに固体高分子型燃料電池セパレータおよび固体高分子型燃料電池
JP2012201950A (ja) * 2011-03-25 2012-10-22 Nisshin Steel Co Ltd 微細粗面化ステンレス鋼板および薄膜Ｓｉ太陽電池の製造法
KR101742088B1 (ko) * 2015-12-23 2017-06-01 주식회사 포스코 친수성 및 접촉저항이 향상된 고분자 연료전지 분리판용 스테인리스강 및 이의 제조 방법
CN111057947A (zh) * 2019-12-09 2020-04-24 宁波宝新不锈钢有限公司 一种具有良好高温强度的铁素体不锈钢及其制备方法
EP4119697A4 (en) * 2020-03-12 2024-04-17 Nippon Steel Stainless Steel Corp FERRITIC STAINLESS STEEL AND ITS MANUFACTURING METHOD

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010062739A (ja) 2008-09-02 2010-03-18 Fujitsu Ltd 増幅回路および光変調器用ドライバ回路
CN102272343A (zh) * 2008-12-29 2011-12-07 Posco公司 用于聚合物燃料电池隔板的不锈钢及其制造方法
CN102471916A (zh) 2009-07-23 2012-05-23 杰富意钢铁株式会社 耐腐蚀性优良的燃料电池用不锈钢及其制造方法
JP2012201951A (ja) * 2011-03-25 2012-10-22 Nisshin Steel Co Ltd 粗大粗面化ステンレス鋼板および色素増感太陽電池の製造法
CN102925950A (zh) * 2011-06-30 2013-02-13 通用电气公司 用于粗化金属表面的方法及由其制造的物品
KR20170013918A (ko) 2014-06-06 2017-02-07 얼라인 테크널러지, 인크. 렌즈 포지셔닝 시스템
CN104746123A (zh) * 2015-04-11 2015-07-01 常州大学 一种在316l不锈钢表面进行电化学改性的技术方法
CN108368612A (zh) * 2015-12-17 2018-08-03 株式会社Posco 具有改善的亲水特性和耐腐蚀性的用于聚合物电解质膜燃料电池的隔板的不锈钢及其制造方法
CN110199047A (zh) 2016-12-22 2019-09-03 株式会社Posco 具有优异的接触电阻的用于聚合物燃料电池隔板的不锈钢及其制造方法
JP2019070187A (ja) * 2017-10-11 2019-05-09 新日鐵住金株式会社 ステンレス鋼材、構成部材、セルおよび燃料電池スタック
JP2021004384A (ja) * 2019-06-25 2021-01-14 日鉄ステンレス株式会社 ステンレス鋼
CN111519229A (zh) * 2020-04-09 2020-08-11 大连理工大学 一种质子交换膜燃料电池不锈钢双极板的电化学表面改性方法

Also Published As

Publication number Publication date
CN115896896A (zh) 2023-04-04
CN114574759A (zh) 2022-06-03
CN114574759B (zh) 2022-12-02

Similar Documents

Publication Publication Date Title
WO2023155264A1 (zh) 用于燃料电池双极板的铁素体不锈钢、表面粗糙度的调控方法、形成钝化膜的方法和用途
EP1726674B1 (en) Metal material for current-carrying member, separator for fuel cell utilizing the same and fuel cell including the same
EP2626440B1 (en) Ferritic stainless steel having excellent corrosion resistance and electrical conductivity, method for producing same, solid polymer fuel cell separator, and solid polymer fuel cell
JP5396487B2 (ja) 高分子燃料電池分離板用ステンレス鋼およびその製造方法
JP5109234B2 (ja) 固体高分子型燃料電池セパレータ用金属材料，それを用いた燃料電池用セパレータ，その燃料電池および固体高分子型燃料電池セパレータ用金属材料の表面粗さ調整処理方法
JP4798298B2 (ja) 導電性と延性に優れた燃料電池セパレータ用ステンレス鋼およびその製造方法
WO2013018320A1 (ja) 燃料電池セパレータ用ステンレス鋼
EP2667439A1 (en) Method for producing stainless steel for fuel cell separators, stainless steel for fuel cell separators, fuel cell separator, and fuel cell
JP5928364B2 (ja) 固体高分子形燃料電池のセパレータ用金属板
WO2011132797A1 (ja) 固体高分子形燃料電池セパレータ用金属板
WO2020153117A1 (ja) 燃料電池のセパレータ用のオーステナイト系ステンレス鋼板およびその製造方法
JP5972877B2 (ja) 燃料電池セパレータ用ステンレス鋼の製造方法
WO2019082591A1 (ja) 燃料電池のセパレータ用のステンレス鋼板の製造方法
CN114875341B (zh) 一种燃料电池双极板用不锈钢及其制备方法
JP2017088931A (ja) 固体高分子型燃料電池用チタン合金、それを用いたチタン材、およびそれを用いた固体高分子型燃料電池
WO2017170067A1 (ja) 固体高分子形燃料電池用セルおよび固体高分子形燃料電池スタック
EP4253589A1 (en) Ferritic stainless steel for bipolar plate of fuel cell, surface roughness adjustment and control method, method for forming passivation film, and use
JP6418362B1 (ja) ステンレス鋼材、構成部材、セルおよび燃料電池スタック
JP5703560B2 (ja) 導電性に優れた燃料電池セパレータ用ステンレス鋼板
CN117867412B (zh) 一种燃料电池双极板高耐蚀性不锈钢
JP2022165345A (ja) 燃料電池用セパレータ及び燃料電池
CN115852243A (zh) 一种高耐蚀耐热预镀镍电池壳钢及其制造方法

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 2022540711

Country of ref document: JP

ENP Entry into the national phase

Ref document number: 2022729406

Country of ref document: EP

Effective date: 20220621