WO2022118768A1 - 表面処理鋼板 - Google Patents
表面処理鋼板 Download PDFInfo
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- WO2022118768A1 WO2022118768A1 PCT/JP2021/043526 JP2021043526W WO2022118768A1 WO 2022118768 A1 WO2022118768 A1 WO 2022118768A1 JP 2021043526 W JP2021043526 W JP 2021043526W WO 2022118768 A1 WO2022118768 A1 WO 2022118768A1
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- alloy layer
- steel sheet
- concentration
- treated steel
- content
- Prior art date
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 256
- 239000010959 steel Substances 0.000 title claims abstract description 256
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 326
- 239000000956 alloy Substances 0.000 claims abstract description 326
- 229910020598 Co Fe Inorganic materials 0.000 claims abstract description 300
- 229910002519 Co-Fe Inorganic materials 0.000 claims abstract description 300
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 28
- 229910052742 iron Inorganic materials 0.000 claims abstract description 20
- 238000002845 discoloration Methods 0.000 abstract description 16
- 239000010410 layer Substances 0.000 description 359
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 286
- 238000007747 plating Methods 0.000 description 110
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 54
- 238000012360 testing method Methods 0.000 description 42
- 238000005275 alloying Methods 0.000 description 38
- 238000010438 heat treatment Methods 0.000 description 36
- 238000000034 method Methods 0.000 description 34
- 238000009792 diffusion process Methods 0.000 description 30
- 238000005259 measurement Methods 0.000 description 20
- 238000004458 analytical method Methods 0.000 description 16
- 238000004519 manufacturing process Methods 0.000 description 13
- 238000005096 rolling process Methods 0.000 description 12
- 239000012535 impurity Substances 0.000 description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 10
- 229910052760 oxygen Inorganic materials 0.000 description 10
- 239000001301 oxygen Substances 0.000 description 10
- 239000002344 surface layer Substances 0.000 description 10
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 9
- 238000009713 electroplating Methods 0.000 description 9
- 230000003647 oxidation Effects 0.000 description 9
- 238000007254 oxidation reaction Methods 0.000 description 9
- 150000002500 ions Chemical class 0.000 description 8
- 238000002791 soaking Methods 0.000 description 8
- 238000001816 cooling Methods 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- 239000008151 electrolyte solution Substances 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 description 6
- 238000004544 sputter deposition Methods 0.000 description 6
- 229910020630 Co Ni Inorganic materials 0.000 description 5
- 229910002440 Co–Ni Inorganic materials 0.000 description 5
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 238000004611 spectroscopical analysis Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- QXZUUHYBWMWJHK-UHFFFAOYSA-N [Co].[Ni] Chemical compound [Co].[Ni] QXZUUHYBWMWJHK-UHFFFAOYSA-N 0.000 description 4
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 4
- 239000004327 boric acid Substances 0.000 description 4
- 238000011088 calibration curve Methods 0.000 description 4
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- KGWWEXORQXHJJQ-UHFFFAOYSA-N [Fe].[Co].[Ni] Chemical compound [Fe].[Co].[Ni] KGWWEXORQXHJJQ-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 239000010960 cold rolled steel Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 3
- 229910052748 manganese Inorganic materials 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- 238000005554 pickling Methods 0.000 description 3
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910000531 Co alloy Inorganic materials 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 2
- 229910000655 Killed steel Inorganic materials 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 229910003271 Ni-Fe Inorganic materials 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 229910002056 binary alloy Inorganic materials 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 238000005097 cold rolling Methods 0.000 description 2
- 238000005238 degreasing Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000921 elemental analysis Methods 0.000 description 2
- 235000019253 formic acid Nutrition 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 239000007773 negative electrode material Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000007774 positive electrode material Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- VGTPCRGMBIAPIM-UHFFFAOYSA-M sodium thiocyanate Chemical compound [Na+].[S-]C#N VGTPCRGMBIAPIM-UHFFFAOYSA-M 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 229910017709 Ni Co Inorganic materials 0.000 description 1
- 229910003267 Ni-Co Inorganic materials 0.000 description 1
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 1
- 229910003262 Ni‐Co Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 208000033897 Systemic primary carnitine deficiency Diseases 0.000 description 1
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- DAPUDVOJPZKTSI-UHFFFAOYSA-L ammonium nickel sulfate Chemical compound [NH4+].[NH4+].[Ni+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DAPUDVOJPZKTSI-UHFFFAOYSA-L 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- GVPFVAHMJGGAJG-UHFFFAOYSA-L cobalt dichloride Chemical compound [Cl-].[Cl-].[Co+2] GVPFVAHMJGGAJG-UHFFFAOYSA-L 0.000 description 1
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 1
- 229940044175 cobalt sulfate Drugs 0.000 description 1
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 1
- MEYVLGVRTYSQHI-UHFFFAOYSA-L cobalt(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Co+2].[O-]S([O-])(=O)=O MEYVLGVRTYSQHI-UHFFFAOYSA-L 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000007772 electroless plating Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 238000002847 impedance measurement Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- LNOPIUAQISRISI-UHFFFAOYSA-N n'-hydroxy-2-propan-2-ylsulfonylethanimidamide Chemical compound CC(C)S(=O)(=O)CC(N)=NO LNOPIUAQISRISI-UHFFFAOYSA-N 0.000 description 1
- LAIZPRYFQUWUBN-UHFFFAOYSA-L nickel chloride hexahydrate Chemical compound O.O.O.O.O.O.[Cl-].[Cl-].[Ni+2] LAIZPRYFQUWUBN-UHFFFAOYSA-L 0.000 description 1
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 1
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 1
- RRIWRJBSCGCBID-UHFFFAOYSA-L nickel sulfate hexahydrate Chemical compound O.O.O.O.O.O.[Ni+2].[O-]S([O-])(=O)=O RRIWRJBSCGCBID-UHFFFAOYSA-L 0.000 description 1
- KERTUBUCQCSNJU-UHFFFAOYSA-L nickel(2+);disulfamate Chemical compound [Ni+2].NS([O-])(=O)=O.NS([O-])(=O)=O KERTUBUCQCSNJU-UHFFFAOYSA-L 0.000 description 1
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000000682 scanning probe acoustic microscopy Methods 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 208000016505 systemic primary carnitine deficiency disease Diseases 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/10—Electroplating with more than one layer of the same or of different metals
- C25D5/12—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/34—Pretreatment of metallic surfaces to be electroplated
- C25D5/36—Pretreatment of metallic surfaces to be electroplated of iron or steel
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
- C25D5/50—After-treatment of electroplated surfaces by heat-treatment
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/10—Primary casings; Jackets or wrappings
-
- 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
- Y02E60/10—Energy storage using batteries
Definitions
- This disclosure relates to surface-treated steel sheets.
- a surface-treated steel sheet for battery containers such as primary batteries and secondary batteries
- a surface-treated steel sheet having nickel (Ni) plating on its surface is used.
- a general alkaline battery is manufactured as follows. First, a positive electrode can is manufactured by deep-drawing and pressing a surface-treated steel plate into the shape of a battery container. Next, the conductive film, the positive electrode material, the separator, the electrolytic solution, the negative electrode material, and the current collector are enclosed in the positive electrode can. As a result, alkaline batteries are manufactured.
- the positive electrode can functions as a battery container and further functions as a current collector. The same applies to other types of batteries.
- the surface-treated steel plate functions as a container for a battery, and when connected to a negative electrode or a positive electrode, also functions as a current collector.
- a surface-treated steel sheet having an alloy layer containing cobalt (Co) in addition to Ni on the surface is used for a battery that requires discharge with a large current (hereinafter, also referred to as high rate characteristic).
- Co is an active metal. Therefore, by including Co in the alloy layer, the contact resistance between the surface-treated steel sheet and the positive electrode material or the negative electrode material is lowered. This makes it possible to enhance the function of the surface-treated steel sheet as a current collector. As a result, the high rate characteristics of the battery are enhanced.
- Patent Document 1 International Publication No. 2019/159794
- Patent Document 2 International Publication No. 2012/147843.
- Patent Document 3 International Publication No. 2019/083044
- the surface-treated steel sheet for a battery container disclosed in International Publication No. 2019/159794 includes a Ni—Co—Fe-based diffusion alloy plating layer on at least one side of the base steel sheet.
- the diffusion alloy plating layer is composed of a Ni—Fe alloy layer and a Ni—Co—Fe alloy layer in order from the base steel plate side.
- the diffusion alloy plating layer has a Ni adhesion amount in the range of 3.0 g / m 2 or more and less than 8.74 g / m 2 , and a Co adhesion amount of 0.26 g / m 2 or more and 1.6 g / m 2 or less.
- the total amount of Ni and Co adhered is less than 9.0 g / m 2 .
- the atomic% is Co: 19.5 to 60%, Fe: 0.5 to 30%, and Co + Fe: 20 to 70%.
- the thickness of the Ni—Fe alloy layer is in the range of 0.3 to 1.3 ⁇ m. It is described in Patent Document 1 that this makes it possible to obtain a surface-treated steel sheet for a battery container having excellent workability while maintaining battery characteristics and liquid leakage resistance.
- the surface-treated steel sheet for a battery container disclosed in International Publication No. 2012/147843 has a surface for a battery container in which a nickel-cobalt alloy layer is formed on the outermost surface of the inner surface of the battery container. It is a treated steel sheet.
- the surface-treated steel sheet for a battery container of Patent Document 2 is characterized in that the Co / Ni value on the surface of the nickel-cobalt alloy layer is in the range of 0.1 to 1.5 by Auger electron spectroscopy.
- Patent Document 2 It is described in Patent Document 2 that this makes it possible to obtain a surface-treated steel sheet for a battery container, which has excellent solubility resistance to an alkaline solution and can secure high battery characteristics equal to or higher than those of the conventional one even after a lapse of time.
- the surface-treated steel sheet disclosed in International Publication No. 2019/083044 includes a steel sheet and a nickel-cobalt-iron diffusion layer formed on the steel sheet as the outermost layer.
- the surface-treated steel plate of Patent Document 3 continuously measures Ni strength, Co strength and Fe strength from the surface side of the nickel-cobalt-iron diffusion layer in the depth direction by a high-frequency glow discharge emission analysis method, and Ni strength. , When the Ni content ratio, Co content ratio and Fe content ratio are determined based on Co strength and Fe strength, the Ni strength in the nickel-cobalt-iron diffusion layer is specified to be 0.5% of the maximum value.
- Patent Document 3 states that, when used as a battery container for a battery using a strongly alkaline electrolytic solution, a surface-treated steel sheet having excellent battery characteristics and capable of suppressing deterioration of the battery characteristics even after a lapse of time can be obtained. It is described in.
- the surface-treated steel sheet is stored for a certain period of time after being manufactured until it is used. It is preferable that discoloration of the surface of the surface-treated steel sheet is suppressed even when the surface-treated steel sheet is stored for a certain period of time.
- Patent Document 4 International Publication No. 2018 / International Publication No. 2018 / International Publication No. 2018 / It is disclosed in No. 181950 (Patent Document 4).
- the surface-treated metal plate disclosed in Patent Document 4 is a surface-treated metal plate including a metal plate and a nickel-cobalt binary alloy layer formed on the metal plate, and is the nickel-cobalt binary alloy.
- the layer is provided with an oxide film having a thickness of 0.5 to 30 nm on the surface when a portion having an oxygen atom content of 5 atomic% or more as measured by X-ray photoelectron spectroscopic analysis is used as an oxide film.
- the amount of increase in the thickness of the oxide film is 28 nm or less when a pressure cooker test is carried out in which the temperature is raised, kept at 105 ° C. and the relative humidity is 100% RH for 72 hours, and the temperature is lowered.
- An object of the present disclosure is to provide a surface-treated steel sheet having low contact resistance and capable of suppressing discoloration of the surface.
- the surface-treated steel sheet of the present disclosure is Steel plate and A Ni—Co—Fe alloy layer containing Ni, Co and Fe is provided on the surface of the steel sheet. In the thickness direction of the Ni—Co—Fe alloy layer, it is on the outermost surface side of the Ni—Co—Fe alloy layer and above the position where the Ni concentration in the Ni—Co—Fe alloy layer is maximum. The Co concentration in the Ni—Co—Fe alloy layer is maximized from the outermost surface of the Ni—Co—Fe alloy layer to a depth of 100 nm.
- the Ni—Co—Fe alloy layer is From the outermost surface of the Ni—Co—Fe alloy layer to the position where the Co concentration becomes maximum, a Ni enriched region in which the Ni concentration increases toward the outermost surface of the Ni—Co—Fe alloy layer is formed. include.
- the surface-treated steel sheet of the present disclosure has low contact resistance and can suppress surface discoloration.
- FIG. 1 is a graph showing the results of measuring the concentrations of Ni, Co, and Fe from the surface of the surface-treated steel sheet of the present embodiment in the thickness direction of the surface-treated steel sheet by glow discharge spectroscopic analysis (GDS).
- FIG. 2 is an enlarged view of the graph of FIG. 1 in the range of 0 to 0.4 ⁇ m in depth.
- FIG. 3 is a cross-sectional view showing an example of the surface-treated steel sheet of the present embodiment.
- FIG. 4 is a cross-sectional view showing an example of a surface-treated steel sheet of another embodiment, which is different from FIG.
- FIG. 5 is a cross-sectional view of an example of an alkaline battery using the surface-treated steel plate of the present embodiment.
- FIG. 1 is a graph showing the results of measuring the concentrations of Ni, Co, and Fe from the surface of the surface-treated steel sheet of the present embodiment in the thickness direction of the surface-treated steel sheet by glow discharge spectroscopic analysis (GDS).
- FIG. 2 is
- FIG. 6 is a graph showing the GDS analysis result of the surface-treated steel sheet of Test No. 2 in the example.
- FIG. 7 is an enlarged view of the graph of FIG. 6 in the range of 0 to 0.4 ⁇ m in depth.
- FIG. 8 is a graph showing the GDS analysis result of the surface-treated steel sheet of Test No. 3 in the example.
- FIG. 9 is an enlarged view of the graph of FIG. 8 in the range of 0 to 0.4 ⁇ m in depth.
- FIG. 10 is a graph showing the GDS analysis result of the surface-treated steel sheet of Test No. 4 in the example.
- FIG. 11 is an enlarged view of the graph of FIG. 10 in the range of 0 to 0.4 ⁇ m in depth.
- FIG. 12 is a graph showing the GDS analysis result of the surface-treated steel sheet of Test No. 5 in the example.
- FIG. 13 is an enlarged view of the graph of FIG. 12 in the range of 0 to 0.4 ⁇ m in depth.
- a surface-treated steel sheet having a nickel (Ni) plating layer has been used as a surface-treated steel sheet for a battery container.
- Ni nickel
- a surface-treated steel sheet having an alloy layer containing cobalt (Co) in addition to Ni has been proposed.
- Co is more easily oxidized than Ni.
- moisture such as dew condensation water adheres to the surface of the surface-treated steel sheet (that is, the outermost surface of the alloy layer).
- the oxygen concentration in the portion in contact with water becomes high.
- the oxygen concentration in the portion not in contact with water becomes low.
- An oxygen concentration cell is formed by a portion having a high oxygen concentration and a portion having a low oxygen concentration. The oxygen concentration cell oxidizes Co in the portion where the oxygen concentration is low.
- the outermost surface of the alloy layer is discolored by Co oxide.
- the present inventors can suppress the discoloration of the surface of the surface-treated steel sheet while reducing the contact resistance of the surface-treated steel sheet. I thought.
- Ni is chemically more stable than Co.
- the present inventors considered that if the Ni concentration on the outermost surface of the alloy layer is increased, the oxidation of Co can be suppressed even when an oxygen concentration cell is formed. As a result, discoloration of the surface-treated steel sheet can be suppressed.
- simply increasing the Ni concentration on the outermost surface of the alloy layer may increase the contact resistance of the surface-treated steel sheet. Therefore, while increasing the Co concentration on the surface layer of the alloy layer, a region is formed on the surface layer of the alloy layer in which the Ni concentration increases toward the outermost surface of the alloy layer. The present inventors considered that this would suppress the oxidation of Co while maintaining the contact resistance of the surface-treated steel sheet low.
- FIG. 1 is a graph showing the results of measuring the concentrations of Ni, Co, and Fe from the surface of the surface-treated steel sheet of the present embodiment in the thickness direction of the surface-treated steel sheet by glow discharge spectroscopic analysis (GDS). The measurement conditions of GDS will be described later.
- FIG. 1 is a GDS analysis result of the surface-treated steel sheet of Test No. 1 in the examples described later.
- the vertical axis of FIG. 1 is the concentration (%) of Ni, Co, and Fe converted from the emission intensity (Intensity) of GDS.
- the horizontal axis of FIG. 1 is the depth ( ⁇ m) from the surface of the surface-treated steel sheet (that is, the outermost surface of the Ni—Co—Fe alloy layer) converted from the Ar sputter time.
- the Ni concentration is 1% from the surface of the surface-treated steel sheet.
- the region up to the position P Ni 1% is defined as the Ni—Co—Fe alloy layer 3.
- the Ni concentration in the Ni—Co—Fe alloy layer 3 is the outermost surface of the steel plate 2 and the Ni—Co—Fe alloy layer 3 in the thickness direction of the Ni—Co—Fe alloy layer 3. It is highest at a certain position ( PHNi ) between.
- the Co concentration in the Ni—Co—Fe alloy layer 3 is from the position ( PHNi ) where the Ni concentration in the Ni—Co—Fe alloy layer 3 is maximum in the thickness direction of the Ni—Co—Fe alloy layer 3. Also becomes maximum on the outermost surface side ( PHCo ) of the Ni—Co—Fe alloy layer 3.
- FIG. 2 is an enlarged view of the graph of FIG. 1 in the range of 0 to 0.4 ⁇ m in depth.
- the Co concentration is maximized ( PHCo ). This makes it possible to increase the Co concentration on the surface layer of the Ni—Co—Fe alloy layer 3. As a result, the contact resistance of the surface-treated steel sheet can be lowered.
- the Ni-concentrated region is formed between the outermost surface of the Ni—Co—Fe alloy layer 3 and the position where the Co concentration is maximum ( PHCo ). 4 is formed.
- the Ni concentration increases toward the outermost surface of the Ni—Co—Fe alloy layer 3. This makes it possible to increase the Ni concentration in the vicinity of the outermost surface of the Ni—Co—Fe alloy layer 3.
- the oxidation of Co in the Ni—Co—Fe alloy layer 3 is suppressed, and the discoloration of the surface of the surface-treated steel sheet can be suppressed.
- the surface-treated steel sheet of the present embodiment was completed based on the above findings, and has the following configuration.
- Ni—Co—Fe alloy layer containing Ni, Co and Fe is provided on the surface of the steel sheet.
- the Co concentration in the Ni—Co—Fe alloy layer is maximized from the outermost surface of the Ni—Co—Fe alloy layer to a depth of 100 nm.
- the Ni—Co—Fe alloy layer is From the outermost surface of the Ni—Co—Fe alloy layer to the position where the Co concentration becomes maximum, a Ni enriched region in which the Ni concentration increases toward the outermost surface of the Ni—Co—Fe alloy layer is formed. Including, surface-treated steel sheet.
- the Ni—Co—Fe alloy layer 3 refers to the surface-treated steel sheet when the concentrations of Ni, Co, and Fe are measured from the surface of the surface-treated steel sheet in the thickness direction of the surface-treated steel sheet by GDS, which will be described later.
- the surface of the surface-treated steel sheet and the outermost surface of the Ni—Co—Fe alloy layer 3 are synonymous.
- the Ni concentration, the Co concentration, and the Fe concentration of the Ni—Co—Fe alloy layer 3 are the mass% of Ni converted from the emission intensity of Ni, Co, and Fe in the analysis by GDS described later, respectively.
- the ratio of Ni (%), the ratio of Co (%), and the ratio of Fe (%) when the sum of the content of Co, the content of Co in mass%, and the content of Fe in mass% is 100%.
- the Ni-concentrated region 4 means that the Ni concentration is high in the thickness direction of the Ni—Co—Fe alloy layer 3 from the position where the Ni concentration is highest to the outermost surface of the Ni—Co—Fe alloy layer 3. The region between the lowest position and the outermost surface of the Ni—Co—Fe alloy layer 3 and the region where the Ni concentration increases toward the outermost surface of the Ni—Co—Fe alloy layer 3.
- the Ni content in the Ni—Co—Fe alloy layer per one side of the steel sheet is 1.34 to 5.36 g / m 2
- the Co content in the Ni—Co—Fe alloy layer is 0.
- the Ni content in the Ni—Co—Fe alloy layer per one side of the steel sheet is 5.36 to 35.6 g / m 2
- the Co content in the Ni—Co—Fe alloy layer is 0.
- the surface-treated steel sheet of the present embodiment includes a steel sheet and a Ni—Co—Fe alloy layer 3 containing Ni, Co and Fe on the surface of the steel sheet.
- FIG. 3 is a cross-sectional view showing an example of the surface-treated steel sheet of the present embodiment.
- the surface-treated steel sheet 1 of the present embodiment includes a steel sheet 2 and a Ni—Co—Fe alloy layer 3.
- the Ni—Co—Fe alloy layer 3 is arranged on the surface of the steel sheet 2.
- the Ni—Co—Fe alloy layer 3 is arranged on both sides of the steel plate 2.
- the arrangement of the Ni—Co—Fe alloy layer 3 is not limited to FIG. As shown in FIG. 4, the Ni—Co—Fe alloy layer 3 may be arranged on only one side of the steel sheet 2.
- the surface-treated steel sheet 1 of the present embodiment can be used as a battery application such as a primary battery and a secondary battery.
- the primary battery is, for example, an alkaline battery and a manganese battery.
- the secondary battery is, for example, a lithium ion battery.
- FIG. 5 is a cross-sectional view of an example of an alkaline battery using the surface-treated steel plate 1 of the present embodiment. With reference to FIG. 5, the surface-treated steel plate 1 is processed into the shape of a battery container.
- a container formed of the surface-treated steel plate 1 contains manganese dioxide 10, which is a positive electrode, zinc 11, which is a negative electrode, a separator 12, and a current collector 13.
- the positive electrode 10 and the negative electrode 11 are infiltrated into the electrolytic solution.
- the outside of the container made of the surface-treated steel plate 1 is covered with the insulator 14.
- the convex portion on the upper part of the alkaline battery in FIG. 5 is the positive electrode terminal 15.
- the surface-treated steel plate 1 When used as a battery container, the surface-treated steel plate 1 functions as a battery container and a current collector.
- the Ni—Co—Fe alloy layer 3 When the Ni—Co—Fe alloy layer 3 is arranged on only one side of the steel plate 2, it is preferable that the Ni—Co—Fe alloy layer 3 is arranged inside the battery container.
- the thickness of the surface-treated steel sheet 1 of the present embodiment is not particularly limited, but is, for example, 0.05 to 1.5 mm. For battery applications such as alkaline batteries, it is, for example, 0.1 to 1.0 mm.
- the thickness of the surface-treated steel sheet 1 can be measured by a well-known method. The thickness of the surface-treated steel sheet 1 is measured by, for example, a micrometer.
- Ni—Co—Fe alloy layer 3 contains Ni, Co and Fe.
- Ni, Co and Fe may be partially present in the thickness direction of the Ni—Co—Fe alloy layer 3 or may be present throughout the Ni—Co—Fe alloy layer 3, respectively. That is, in the surface-treated steel sheet 1 of the present embodiment, Ni, Co and Fe may not always be contained in the entire area of the Ni—Co—Fe alloy layer 3 in the thickness direction.
- the boundary between the steel sheet 2 and the Ni—Co—Fe alloy layer 3 is at a position where the Ni concentration is 1% (P Ni 1 % ). That is, the position where the Ni concentration is 1% (P Ni 1 % ) is the surface of the steel sheet 2. From the surface of the steel sheet 2 toward the outermost surface of the Ni—Co—Fe alloy layer 3, the Ni concentration increases, and the Ni concentration becomes maximum at a certain position ( PHNi ). In the thickness direction of the Ni—Co—Fe alloy layer 3, on the outermost surface side of the Ni—Co—Fe alloy layer 3 from the position ( PHNi ) where the Ni concentration in the Ni—Co—Fe alloy layer 3 is maximum. The Co concentration in the Ni—Co—Fe alloy layer is maximized ( PHCo ).
- FIG. 2 is an enlarged view of the graph of FIG. 1 in the range of 0 to 0.4 ⁇ m in depth.
- the thickness direction of the Ni—Co—Fe alloy layer 3 in the Ni—Co—Fe alloy layer 3 from the outermost surface of the Ni—Co—Fe alloy layer 3 to a depth of 100 nm.
- the Co concentration is maximized.
- the region from the outermost surface of the Ni—Co—Fe alloy layer 3 to a depth of 100 nm is also referred to as the surface layer of the Ni—Co—Fe alloy layer 3. Refer to.
- the Co concentration in the Ni—Co—Fe alloy layer 3 becomes maximum at a depth of about 50 nm from the outermost surface of the Ni—Co—Fe alloy layer 3.
- the position ( PHCo ) in the Ni—Co—Fe alloy layer 3 where the Co concentration is maximum is not limited to the position shown in FIG.
- the Co concentration in the Ni—Co—Fe alloy layer 3 may be maximum from the outermost surface of the Ni—Co—Fe alloy layer 3 to a depth of 100 nm.
- the outermost surface side of the Ni—Co—Fe alloy layer 3 and the Ni—Co—Fe alloy layer from the position where the Ni concentration is maximum ( PHNi ).
- the contact resistance of the surface-treated steel plate 1 can be lowered.
- the battery using the surface-treated steel plate 1 can be discharged with a large current.
- the thickness of the Ni—Co—Fe alloy layer 3 is not particularly limited and is appropriately set according to the intended use.
- the thickness of the Ni—Co—Fe alloy layer 3 is, for example, 0.1 to 10.0 ⁇ m.
- the thickness of the Ni—Co—Fe alloy layer 3 is, for example, 0.1 to 5.0 ⁇ m.
- the Ni—Co—Fe alloy layer 3 is specified by the following method.
- the Ni concentration, Co concentration and Fe concentration are measured from the surface of the surface-treated steel sheet 1 in the thickness direction of the surface-treated steel sheet 1 by glow discharge spectroscopic analysis (GDS).
- GDS glow discharge spectroscopic analysis
- a high-frequency glow discharge emission surface analyzer manufactured by HORIBA, Ltd., model number: GD-Profiler2
- the emission intensity of Ni (Intensity), the emission intensity of Co, and the emission intensity of Fe are converted into Ni content (mass%), Co content (mass%), and Fe content (mass%), respectively.
- the ratio of Ni (%), the ratio of Co (%) and the ratio of Fe where the sum of the obtained Ni content (% by mass), Co content (% by mass) and Fe content (% by mass) is 100%. Find (%).
- the obtained Ni ratio (%), Co ratio (%), and Fe ratio (%) are defined as Ni concentration (%), Co concentration (%), and Fe concentration (%), respectively.
- the GDS measurement conditions are as follows. H. V. : Fe is 785V, Ni is 630V, Co is 720V Anode diameter: ⁇ 4 mm Gas: Ar Gas pressure: 600Pa Output: 35W
- Measurement data with a depth of less than 0.006 ⁇ m (6 nm) converted from the Ar sputtering time may contain noise due to reasons such as signal instability. That is, the measurement data having a depth of less than 0.006 ⁇ m (6 nm) converted from the Ar sputtering time may not always be able to accurately measure the Ni—Co—Fe alloy layer 3. Therefore, in the GDS measurement of the surface-treated steel sheet 1 of the present embodiment, only the data having a depth of 0.006 ⁇ m or more converted from the Ar sputtering time is used. Specifically, the depth is 0 ⁇ m at the first point where the depth converted from the Ar sputter time is 0.006 ⁇ m or more.
- the region from the surface of the surface-treated steel sheet 1 to the position where the Ni concentration is 1% (P Ni 1 % ) is defined as the Ni—Co—Fe alloy layer 3.
- the position on the steel sheet 2 side where the Ni concentration is 1% is defined as the boundary between the Ni—Co—Fe alloy layer 3 and the steel sheet 2.
- the distance from the surface of the surface-treated steel sheet 1 to the position where the Ni concentration becomes 1% is defined as the thickness ( ⁇ m) of the Ni—Co—Fe alloy layer 3.
- the position where the Ni concentration is maximum ( PHNi ) and the position where the Co concentration is maximum ( PHCo ) are specified. Then, it is confirmed that the Co concentration is maximum on the outermost surface side of the Ni—Co—Fe alloy layer 3 rather than the position where the Ni concentration is maximum in the thickness direction of the Ni—Co—Fe alloy layer 3.
- the Ni—Co—Fe alloy layer 3 includes a Ni enriched region 4.
- the Ni-concentrated region 4 is a Ni in the thickness direction of the Ni—Co—Fe alloy layer 3 from the position where the Ni concentration is highest ( PHNi ) to the outermost surface of the Ni—Co—Fe alloy layer 3.
- the Ni-enriched region 4 is located between the outermost surface of the Ni—Co—Fe alloy layer 3 and the position where the Co concentration is maximum ( PHCo ). This makes it possible to increase the Ni concentration in the vicinity of the outermost surface of the Ni—Co—Fe alloy layer 3. As a result, the oxidation of Co on the surface layer of the Ni—Co—Fe alloy layer 3 is suppressed, and the discoloration of the surface of the surface-treated steel sheet can be suppressed.
- the maximum Ni concentration in the Ni-enriched region 4 is lower than the maximum Ni concentration in the Ni—Co—Fe alloy layer 3.
- the Ni concentration decreases from the position ( PHNi ) in the Ni—Co—Fe alloy layer 3 where the Ni concentration becomes maximum toward the outermost surface of the Ni—Co—Fe alloy layer 3. Then, at the position ( PHNi ) in the Ni—Co—Fe alloy layer 3 where the Ni concentration is maximum and the position ( PLNi ) between the outermost surface of the Ni—Co—Fe alloy layer 3, the Ni concentration is extremely small. It becomes a value. The Ni concentration increases from the point where the Ni concentration becomes the minimum value ( PLNi ) to the outermost surface of the Ni—Co—Fe alloy layer 3.
- the Ni concentration continues to increase up to the outermost surface of the Ni—Co—Fe alloy layer 3.
- the Ni concentration does not have to change temporarily from the point where the Ni concentration becomes the minimum value ( PLNi ) toward the outermost surface of the Ni—Co—Fe alloy layer 3, but the Ni concentration does not have to change. Does not decrease. This is because when the Ni concentration decreases in the Ni-concentrated region 4, the oxidation suppressing function of the surface of the surface-treated steel sheet 1 deteriorates, and as a result, the surface of the surface-treated steel sheet 1 may be discolored.
- the position where the Co concentration is maximum ( PHCo ) in the Ni—Co—Fe alloy layer 3 and the position where the Ni concentration is the minimum value ( PLNi ) coincide with each other. There is. However, depending on the diffusion state of Fe in the Ni—Co—Fe alloy layer 3, the position where the Co concentration is maximum ( PHCo ) and the position where the Ni concentration is the minimum value ( PLNi ) may not match. be.
- the thickness of the Ni-concentrated region 4 is 0.01 ⁇ m or more, the Ni concentration in the vicinity of the outermost surface of the Ni—Co—Fe alloy layer 3 can be stably increased. As a result, the oxidation of Co in the Ni—Co—Fe alloy layer 3 can be suppressed more stably.
- the thickness of the Ni-concentrated region 4 is 0.15 ⁇ m or less, the Co concentration on the surface layer of the Ni—Co—Fe alloy layer is kept relatively high. As a result, the contact resistance of the surface-treated steel sheet 1 can be lowered more stably. Therefore, the thickness of the Ni-enriched region 4 is preferably 0.01 to 0.15 ⁇ m.
- the lower limit of the thickness of the Ni-concentrated region 4 is more preferably 0.02 ⁇ m, further preferably 0.03 ⁇ m, still more preferably 0.04 ⁇ m, still more preferably 0.05 ⁇ m, still more preferably. Is 0.06 ⁇ m.
- the upper limit of the thickness of the Ni-concentrated region 4 is more preferably 0.12 ⁇ m, further preferably 0.11 ⁇ m, still more preferably 0.10 ⁇ m, still more preferably 0.09 ⁇ m, still more preferably. Is 0.08 ⁇ m, more preferably 0.07 ⁇ m, still more preferably 0.06 ⁇ m.
- the thickness of the Ni-enriched region 4 is measured by the following method. First, GDS measurement is performed on the surface-treated steel sheet 1 by the above-mentioned method. In the thickness direction of the Ni—Co—Fe alloy layer 3, the position where the Ni concentration is the lowest ( PHNi ) to the position where the Ni concentration is the lowest from the outermost surface of the Ni—Co—Fe alloy layer 3 (P). A region between LNi ) and the outermost surface of the Ni—Co—Fe alloy layer 3 is specified, and a region in which the Ni concentration increases toward the outermost surface of the Ni—Co—Fe alloy layer 3 is specified.
- the thickness of this region is defined as the thickness ( ⁇ m) of the Ni enriched region 4. That is, the distance in the thickness direction of the Ni—Co—Fe alloy layer 3 from the position where the Ni concentration becomes the minimum value ( PLNi ) to the outermost surface of the Ni—Co—Fe alloy layer 3 is the Ni enrichment region.
- the thickness is 4 ( ⁇ m).
- Ni-Co-Fe alloy layer top surface Ni concentration When the Ni concentration on the outermost surface of the Ni—Co—Fe alloy layer 3 is 10% or more, discoloration of the surface-treated steel sheet 1 can be suppressed more stably. On the other hand, when the Ni concentration on the outermost surface of the Ni—Co—Fe alloy layer 3 is 90% or less, the low contact resistance of the surface-treated steel sheet 1 can be maintained more stably. Therefore, the Ni concentration on the outermost surface of the Ni—Co—Fe alloy layer 3 is preferably 10 to 90%. The lower limit of the Ni concentration on the outermost surface of the Ni—Co—Fe alloy layer 3 is more preferably 20%, still more preferably 30%. The upper limit of the Ni concentration on the outermost surface of the Ni—Co—Fe alloy layer 3 is more preferably 80%, further preferably 70%, still more preferably 60%, still more preferably 55%.
- the Ni concentration on the outermost surface of the Ni—Co—Fe alloy layer 3 has a depth of 0.006 ⁇ m or more converted from the Ar sputter time when the Ni concentration, the Co concentration and the Fe concentration are measured by GDS by the above method.
- the Ni concentration at the first depth As described above, the measurement data having a depth of less than 0.006 ⁇ m converted from the Ar sputter time is excluded from the analysis target because the Ni—Co—Fe alloy layer 3 may not always be accurately measured.
- the ratio of the Co concentration to the Ni concentration at the position where the Co concentration is maximum ( PHCo ) in the thickness direction of the Ni—Co—Fe alloy layer 3 is 0.5 or more. If the ratio of the Co concentration to the Ni concentration at the position where the Co concentration is maximum ( PHCo ) is high, it is easy to maintain the contact resistance of the surface-treated steel sheet 1 at a low level. Therefore, the lower limit of the ratio of the Co concentration to the Ni concentration at the position where the Co concentration is maximum ( PHCo ) in the thickness direction of the Ni—Co—Fe alloy layer 3 is more preferably 1.0, and even more preferably 1.0.
- the upper limit of the ratio of the Co concentration to the Ni concentration at the position where the Co concentration is maximum ( PHCo ) in the thickness direction of the Ni—Co—Fe alloy layer is preferably 10.0, more preferably 9.5. Yes, more preferably 9.0.
- the Co concentration / Ni concentration ratio is measured by the following method. First, GDS measurement is performed by the above method. The Ni concentration and the Co concentration are measured at the position ( PHCo ) where the Co concentration is maximum in the thickness direction of the Ni—Co—Fe alloy layer. The Co concentration / Ni concentration ratio is calculated by dividing the obtained Co concentration by the Ni concentration.
- the Fe concentration in the Ni—Co—Fe alloy layer 3 decreases from the steel plate 2 toward the outermost surface of the Ni—Co—Fe alloy layer 3.
- the case where Fe is diffused to the outermost surface of the Ni—Co—Fe alloy layer 3 is also referred to as total diffusion.
- the case where Fe is not diffused to the outermost surface of the Ni—Co—Fe alloy layer 3 is also referred to as partial diffusion.
- the Ni—Co—Fe alloy layer 3 of the surface-treated steel sheet 1 of the present embodiment may be fully diffused or partially diffused.
- Ni content and preferable Co content in the Ni—Co—Fe alloy layer 3 Preferably, the Ni content and the Co content in the Ni—Co—Fe alloy layer 3 per one side of the steel sheet 2 are as follows.
- Ni content in Ni—Co—Fe alloy layer 3 1.34 to 35.6 g / m 2
- the Ni content in the Ni—Co—Fe alloy layer 3 is 1.34 g / m 2 or more, the rust resistance of the surface-treated steel sheet 1 is enhanced.
- the Ni content in the Ni—Co—Fe alloy layer 3 exceeds 35.6 g / m 2 , the rust resistance of the surface-treated steel sheet 1 is saturated. If the Ni content in the Ni—Co—Fe alloy layer 3 is 35.6 g / m 2 or less, the cost can be suppressed. Therefore, the Ni content in the Ni—Co—Fe alloy layer 3 is preferably 1.34 to 35.6 g / m 2 .
- a more preferable lower limit of the Ni content in the Ni—Co—Fe alloy layer 3 is 5.36 g / m 2 , and even more preferably 8.93 g / m 2 .
- a more preferable upper limit of the Ni content in the Ni—Co—Fe alloy layer 3 is 26.8 g / m 2 , and even more preferably 17.9 g / m 2 .
- Co content in Ni—Co—Fe alloy layer 3 0.45 to 1.34 g / m 2
- the Co content in the Ni—Co—Fe alloy layer 3 is 0.45 g / m 2 or more, it is easy to maintain the contact resistance of the surface-treated steel sheet 1 at a low level.
- the Co content in the Ni—Co—Fe alloy layer 3 is 1.34 g / m 2 or less, the solubility of the Ni—Co—Fe alloy layer 3 in the alkaline electrolytic solution is enhanced. Therefore, the Co content in the Ni—Co—Fe alloy layer 3 is preferably 0.45 to 1.34 g / m 2 .
- a more preferable lower limit of the Co content in the Ni—Co—Fe alloy layer 3 is 0.54 g / m 2 , and even more preferably 0.63 g / m 2 .
- a more preferable upper limit of the Co content in the Ni—Co—Fe alloy layer 3 is 1.11 g / m 2 , and even more preferably 0.89 g / m 2 .
- Ni content and Co content in the Ni—Co—Fe alloy layer 3 in the case of total diffusion are preferably as follows.
- Ni content in Ni—Co—Fe alloy layer 3 in the case of total diffusion 1.34 to 5.36 g / m 2
- the Ni content in the Ni—Co—Fe alloy layer 3 is 1.34 g / m 2 or more, the rust resistance of the surface-treated steel sheet 1 is enhanced.
- the Ni content in the Ni—Co—Fe alloy layer 3 is 5.36 g / m 2 or less, Fe is likely to diffuse to the outermost surface of the Ni—Co—Fe alloy layer 3. Therefore, when the Ni—Co—Fe alloy layer 3 is fully diffused, the Ni content in the Ni—Co—Fe alloy layer 3 is preferably 1.34 to 5.36 g / m 2 .
- the more preferable lower limit of the Ni content in the Ni—Co—Fe alloy layer 3 is 2.23 g / m 2 , and more preferably 3.12 g / m 2 .
- the more preferable upper limit of the Ni content in the Ni—Co—Fe alloy layer 3 is 4.45 g / m 2 , and more preferably 3.56 g / m 2 .
- Co content in Ni—Co—Fe alloy layer 3 in the case of total diffusion 0.45 to 1.34 g / m 2
- the Co content in the Ni—Co—Fe alloy layer 3 is 0.45 g / m 2 or more, it is easy to maintain the contact resistance of the surface-treated steel sheet 1 at a low level.
- the Co content in the Ni—Co—Fe alloy layer 3 is 1.34 g / m 2 or less, the solubility of the Ni—Co—Fe alloy layer 3 in the alkaline electrolytic solution is enhanced. Therefore, the Co content in the Ni—Co—Fe alloy layer 3 in the case of total diffusion is preferably 0.45 to 1.34 g / m 2 .
- the more preferable lower limit of the Co content in the Ni—Co—Fe alloy layer 3 in the case of total diffusion is 0.54 g / m 2 , and more preferably 0.63 g / m 2 .
- the more preferable upper limit of the Co content in the Ni—Co—Fe alloy layer 3 in the case of total diffusion is 1.11 g / m 2 , and more preferably 0.89 g / m 2 .
- Ni content and Co content in the Ni—Co—Fe alloy layer 3 in the case of partial diffusion are preferably as follows.
- Ni content in Ni—Co—Fe alloy layer 3 in the case of partial diffusion 5.36 to 35.6 g / m 2
- the Ni content in the Ni—Co—Fe alloy layer 3 is 5.36 g / m 2 or more, it is easy to manufacture the partially diffused Ni—Co—Fe alloy layer 3.
- the Ni content in the Ni—Co—Fe alloy layer 3 is 35.6 g / m 2 or less, the cost can be suppressed. Therefore, when the Ni—Co—Fe alloy layer 3 is partially diffused, the Ni content in the Ni—Co—Fe alloy layer 3 is preferably 5.36 to 35.6 g / m 2 .
- the more preferable lower limit of the Ni content in the Ni—Co—Fe alloy layer 3 is 8.93 g / m 2 , and more preferably 17.9 g / m 2 .
- the more preferable upper limit of the Ni content in the Ni—Co—Fe alloy layer 3 is 31.3 g / m 2 , and more preferably 22.3 g / m 2 .
- Co content in Ni—Co—Fe alloy layer 3 in the case of partial diffusion 0.45 to 1.34 g / m 2
- the Co content in the Ni—Co—Fe alloy layer 3 is 0.45 g / m 2 or more, it is easy to maintain the contact resistance of the surface-treated steel sheet 1 at a low level.
- the Co content in the Ni—Co—Fe alloy layer 3 is 1.34 g / m 2 or less, the solubility of the Ni—Co—Fe alloy layer 3 in the alkaline electrolytic solution is enhanced. Therefore, the Co content in the Ni—Co—Fe alloy layer 3 in the case of partial diffusion is more preferably 0.45 to 1.34 g / m 2 .
- the more preferable lower limit of the Co content in the Ni—Co—Fe alloy layer 3 in the case of partial diffusion is 0.54 g / m 2 , and more preferably 0.63 g / m 2 .
- the more preferable upper limit of the Co content in the Ni—Co—Fe alloy layer 3 in the case of partial diffusion is 1.11 g / m 2 , and more preferably 0.89 g / m 2 .
- the chemical composition of the Ni—Co—Fe alloy layer 3 of the surface-treated steel sheet 1 of the present embodiment may be a chemical composition composed of Ni, Co, Fe and impurities.
- the impurity is, for example, one or more elements selected from the group consisting of carbon (C), oxygen (O), aluminum (Al), silicon (Si), phosphorus (P) and sulfur (S). Impurities may be contained, for example, in a total of 0.1% by mass or less.
- Ni content and the Co content in the Ni—Co—Fe alloy layer 3 are measured by the following method. First, a surface-treated steel sheet 1 provided with a Ni—Co—Fe alloy layer 3 is prepared. Next, elemental analysis is performed on the Ni—Co—Fe alloy layer 3 of the surface-treated steel sheet 1 using a fluorescent X-ray analyzer. The fluorescent X-ray analyzer prepares a calibration curve in advance using a standard sample having a known Ni content and a standard sample having a known Co content. Based on this calibration curve, the Ni content (g / m 2 ) and the Co content (g / m 2 ) in the Ni—Co—Fe alloy layer 3 are determined.
- the impedance value ( ⁇ ) of the surface-treated steel sheet 1 of the present embodiment is preferably 50 ( ⁇ ) or less.
- the impedance value ( ⁇ ) is 0.3 V vs. the surface-treated steel sheet 1 in a 35% KOH aqueous solution at 60 ° C.
- Impedance value ( ⁇ ) at a frequency of 0.1 Hz measured after holding a constant potential at Hg / HgO for 10 days.
- the upper limit of the impedance value ( ⁇ ) is more preferably 45, still more preferably 40, still more preferably 30, still more preferably 20, still more preferably 10, and even more preferably 5.
- the lower limit of the impedance value ( ⁇ ) is not particularly limited, but is 1, for example.
- the ( ⁇ E * ) of the surface-treated steel sheet 1 of the present embodiment is preferably 3.0 or less.
- the color difference ( ⁇ E * ) is the color difference ( ⁇ E * ) obtained from the L * a * b * values before and after holding the surface-treated steel sheet 1 at a temperature of 60 ° C. and a humidity of 90% RH for 240 hours.
- the upper limit of the color difference ( ⁇ E * ) is more preferably 2.9, still more preferably 2.7, still more preferably 2.5, still more preferably 2.3, still more preferably 2.1. It is more preferably 2.0, further preferably 1.9, and even more preferably 1.6.
- the lower limit of the color difference ( ⁇ E * ) is not particularly limited, but is, for example, 0.
- the chemical composition of the steel sheet 2 is not particularly limited.
- the steel plate 2 is, for example, a low carbon steel containing 0.25% by mass or less of carbon (C), an ultra-low carbon steel containing less than 0.01% by mass of C, and an ultra-low carbon steel containing Ti and Nb. It may be selected from the group consisting of the obtained non-aging ultra-low carbon steel.
- the steel plate 2 may be a cold-rolled steel plate. Cold-rolled steel sheets of low carbon steel are specified, for example, as SPCC, SPCD, SPCE, SPCF and SPCG of JIS (Japanese Industrial Standards) G3141 (2017).
- the steel plate 2 may be these cold-rolled steel plates. Further, the steel plate 2 may be aluminum killed steel.
- the surface-treated steel sheet 1 of the present embodiment includes the steel sheet 2 and the Ni—Co—Fe alloy layer 3 containing Ni, Co, and Fe on the surface of the steel sheet 2.
- the outermost surface side of the Ni—Co—Fe alloy layer 3 is located on the outermost surface side of the Ni—Co—Fe alloy layer 3 from the position ( PHNi ) where the Ni concentration in the Ni—Co—Fe alloy layer 3 is maximum.
- the Co concentration in the Ni—Co—Fe alloy layer 3 is maximized from the outermost surface of the Ni—Co—Fe alloy layer 3 to a depth of 100 nm ( PHCo ).
- the Ni—Co—Fe alloy layer 3 is formed on the outermost surface of the Ni—Co—Fe alloy layer 3 from the outermost surface of the Ni—Co—Fe alloy layer 3 to the position where the Co concentration is maximum ( PHCo ).
- a Ni-concentrated region 4 in which the Ni concentration increases toward the surface is formed. Therefore, the surface-treated steel sheet 1 of the present embodiment has low contact resistance and can suppress surface discoloration.
- the method for manufacturing the surface-treated steel sheet 1 of the present embodiment described above will be described.
- the method for manufacturing the surface-treated steel sheet 1 described below is an example of the method for manufacturing the surface-treated steel sheet 1 of the present embodiment. Therefore, the surface-treated steel sheet 1 having the above-mentioned structure may be manufactured by a manufacturing method other than the manufacturing methods described below. However, the manufacturing method described below is a preferable example of the manufacturing method of the surface-treated steel sheet 1 of the present embodiment.
- the method for manufacturing the surface-treated steel plate 1 of the present embodiment includes a step of preparing the steel plate 2 (steel plate preparation step), a step of forming a Ni plating layer on the surface of the steel plate 2 (Ni plating step), and a step of forming a Ni plating layer on the Ni plating layer.
- a step of forming a Co-plated layer (Co-plating step), a step of alloying and heat-treating a steel plate having a Ni-plated layer and a Co-plated layer (an alloying heat-treated step), and temper rolling of a steel plate that has been alloyed and heat-treated. Includes the process of carrying out the tempering and rolling process.
- each step will be described.
- the steel plate 2 may be supplied from a third party or may be manufactured.
- the steel sheet 2 is manufactured by the following method.
- a molten steel having the above-mentioned chemical composition is produced.
- a slab is manufactured using the manufactured molten steel.
- Hot rolling, pickling and cold rolling are carried out on the produced slabs.
- Annealing and temper rolling may be carried out after cold rolling.
- the steel sheet 2 can be manufactured by the above steps.
- the thickness of the steel plate 2 is not particularly limited, and is selected according to the use of the surface-treated steel plate 1.
- the thickness of the steel plate 2 is, for example, 0.05 to 1.5 mm.
- Ni plating process In the Ni plating step, a Ni plating layer composed of Ni and impurities is formed on the surface of the steel sheet 2. Specifically, the steel plate 2 is brought into contact with the Ni plating bath to perform electrolytic plating or electroless plating. The steel plate 2 may be immersed in a Ni plating bath to perform electrolytic plating. A well-known Ni plating bath can be used as the Ni plating bath.
- the Ni plating bath is selected from the group consisting of, for example, a watt bath, a sulfuric acid bath, a sulfamic acid bath, a wood bath, a borofluoride bath, a chloride bath and a citric acid bath.
- the Ni plating bath contains Ni ions.
- Ni ions may be added to the Ni plating bath as one or more selected from the group consisting of nickel sulfate, nickel ammonium sulfate, nickel chloride and nickel sulfamate.
- the Ni plating bath may contain other components in addition to Ni ions.
- the other component is, for example, one or more selected from the group consisting of boric acid, hydrochloric acid, sodium thiocyanate, citric acid, brighteners, pH adjusters and surfactants. Other components are appropriately set according to the type of Ni plating bath.
- Plating conditions such as Ni plating bath temperature, Ni plating bath pH, and Ni plating processing time can be set as appropriate.
- plating may be performed at a Ni plating bath temperature of 25 ° C to 70 ° C and a pH of the Ni plating bath of 1 to 5.
- plating may be performed at a current density of 1 to 50 A / dm 2 .
- the Ni plating treatment time is appropriately set according to the adhesion amount of Ni plating (that is, the Ni content of the Ni—Co—Fe alloy layer 3) (g / m 2 ).
- Ni plating layer forming step for example, nickel (II) sulfate hexahydrate: 240 to 380 g / L, nickel (II) chloride hexahydrate: 0.40 to 80 g / L, and boric acid: 20 to 55 g.
- a watt bath containing / L may be used. Using this watt bath, electrolytic plating was performed at a Ni plating bath pH of 3.5 to 4.5, a Ni plating bath temperature of 45 to 55 ° C., and a current density of 1 to 40 A / dm 2 . May be good.
- the Ni plating treatment time is appropriately set according to the adhesion amount of Ni plating (that is, the Ni content of the Ni—Co—Fe alloy layer 3) (g / m 2 ). As a result, a Ni plating layer composed of Ni and impurities can be formed on the surface of the steel sheet 2.
- the Ni adhesion amount of the Ni plating layer is the same as the Ni content in the Ni—Co—Fe alloy layer 3 described above. That is, it is preferable to adjust the plating conditions so that the amount of Ni adhered to one side of the steel sheet 2 is 1.34 to 35.6 g / m 2 .
- the amount of Ni adhered to one side of the steel sheet 2 is preferably 1.34 to 5.36 g / m 2 .
- the Ni—Co—Fe alloy layer 3 is partially diffused, the amount of Ni adhered to one side of the steel sheet 2 is preferably 5.36 to 35.6 g / m 2 .
- Co plating process In the Co plating step, a Co plating layer composed of Co and impurities is formed on the Ni plating layer. Specifically, the Ni plating layer on the surface of the steel sheet 2 is brought into contact with the Co plating bath to perform electrolytic plating.
- the steel plate 2 provided with the Ni plating layer may be immersed in a Co plating bath to perform electrolytic plating.
- As the Co plating bath a commercially available Co plating bath can be used.
- the Co plating bath contains Co ions.
- the content of Co ions is, for example, 0.5 to 2.0 mol / L.
- Co ions may be added to the Co plating bath as one or more selected from the group consisting of cobalt sulfate and cobalt chloride.
- the Co plating bath may contain other components in addition to Co ions.
- the other component is, for example, one or more selected from the group consisting of formic acid, boric acid, hydrochloric acid, sodium thiocyanate, citric acid, brighteners, pH adjusters and surfactants.
- Other components are appropriately set according to the type of Co plating bath.
- Plating conditions such as the Co plating bath temperature, the pH of the Co plating bath, and the Co plating processing time can be appropriately set.
- plating may be performed at a Co plating bath temperature of 25 ° C. to 70 ° C. and a pH of the Co plating bath of 1 to 5 ° C.
- electrolytic plating may be performed at a current density of 1 to 50 A / dm 2 .
- the Co plating treatment time is appropriately set according to the adhesion amount of Co plating (that is, the Co content of the Ni—Co—Fe alloy layer 3) (g / m 2 ).
- Co plating layer forming step for example, cobalt (II) sulfate heptahydrate: 240 to 330 g / L, boric acid: 20 to 55 g / L, and formic acid: 15 to 30 g / L, sulfuric acid: 0.5 to 3 g.
- a Co plating bath containing / L may be used. Using this Co plating bath, electrolytic plating may be performed at a pH of the Co plating bath of 1 to 3, a Co plating bath temperature of 40 to 60 ° C., and a current density of 1 to 40 A / dm 2 .
- the Co plating treatment time is appropriately set according to the adhesion amount of Co plating (that is, the Co content of the Ni—Co—Fe alloy layer 3) (g / m 2 ). As a result, a Co plating layer can be formed on the Ni plating layer.
- the Co adhesion amount of the Co plating layer is the same as the Co content in the Ni—Co—Fe alloy layer 3 described above. That is, it is preferable to adjust the plating conditions so that the amount of Co adhered to one side of the steel sheet 2 is 0.45 to 1.34 g / m 2 .
- the steel sheet 2 provided with the Ni plating layer and the Co plating layer is alloyed and heat treated.
- Ni in the Ni plating layer, Co in the Co plating layer, and Fe contained in the steel sheet 2 diffuse with each other to form the Ni—Co—Fe alloy layer 3.
- a well-known heating furnace can be used as the alloying heat treatment furnace.
- the alloying heat treatment is carried out by continuously supplying the steel plate 2 to the heating furnace.
- the Ni-concentrated region 4 can be formed in the Ni—Co—Fe alloy layer 3 by adjusting the alloying heat treatment conditions. In other words, by alloying heat treatment under appropriate conditions, the Ni—Co—Fe alloy layer can be formed between the outermost surface of the Ni—Co—Fe alloy layer 3 and the position where the Co concentration is maximum ( PHCo ). A Ni-enriched region 4 can be formed in which the Ni concentration increases toward the outermost surface. The Ni-concentrated region 4 suppresses the oxidation of Co in the Ni—Co—Fe alloy layer 3 and suppresses the discoloration of the surface-treated steel sheet 1.
- the maximum temperature during the alloying heat treatment is less than 630 ° C., the mutual diffusion of Ni in the Ni plating layer, Co in the Co plating layer, and Fe contained in the steel sheet 2 becomes insufficient. In this case, the adhesion of the Ni—Co—Fe alloy layer 3 is lowered.
- the treatment temperature during the alloying heat treatment is 630 to 860 ° C.
- the preferable lower limit of the treatment temperature during the alloying heat treatment is 720 ° C, more preferably 760 ° C.
- the preferred upper limit of the treatment temperature during the alloying heat treatment is 830 ° C, more preferably 810 ° C.
- the maximum temperature at the time of alloying heat treatment means the maximum temperature reached by the steel sheet 2 in the heating furnace.
- the dew point at the time of alloying heat treatment is ⁇ 25 ° C. or higher.
- the lower limit of the preferable dew point during the alloying heat treatment is ⁇ 20 ° C., more preferably ⁇ 10 ° C.
- the upper limit of the dew point during the alloying heat treatment is not particularly limited, but is, for example, 5 ° C, preferably less than 0 ° C. If the dew point during the alloying heat treatment is less than 0 ° C., the Co concentration can be relatively increased on the surface of the surface-treated steel sheet 1. As a result, the contact resistance of the surface-treated steel sheet 1 can be further reduced.
- Ni-concentrated region can be formed from the outermost surface of the Ni—Co—Fe alloy layer 3 to the position where the Co concentration is maximum ( PHCo ) due to the dew point during the alloying heat treatment. It is considered as follows. Comparing Ni and Co, Ni is an element that is less likely to be oxidized, and Co is an element that is more easily oxidized. Under conditions where the dew point is -25 ° C or higher, the oxygen concentration is higher than that of the conventional alloying heat treatment atmosphere, and oxidation easily proceeds. The Co-plated layer formed as the outermost layer before the alloying heat treatment is oxidized while diffusing toward the inside of the Ni—Co—Fe alloy layer 3 by the alloying heat treatment in a high dew point atmosphere.
- the Ni plating layer formed under the Co plating layer before the alloying heat treatment diffuses toward the outermost surface of the Ni—Co—Fe alloy layer 3 by the alloying heat treatment in a high dew point atmosphere. While being oxidized. At this time, Ni is concentrated in the vicinity of the outermost surface of the Ni—Co—Fe alloy layer 3. As a result, the Ni concentration increases toward the outermost surface of the Ni—Co—Fe alloy layer 3 from the outermost surface of the Ni—Co—Fe alloy layer 3 to the position where the Co concentration becomes maximum ( PHCo ). , Ni enriched region 4 is formed.
- the atmosphere gas during the alloying heat treatment is not particularly limited, but is, for example, N 2 + 2 to 25% H 2 .
- the dew point can be adjusted by, for example, spraying water vapor so as to have the above dew point.
- Soaking time 10 to 180 seconds If the soaking time during the alloying process is less than 10 seconds, the mutual diffusion of Ni in the Ni plating layer, Co in the Co plating layer, and Fe contained in the steel sheet 2 is insufficient. Will be. In this case, the adhesion of the Ni—Co—Fe alloy layer 3 is lowered. On the other hand, if the soaking time during the alloying treatment exceeds 180 seconds, the hardness of the steel sheet 2 decreases. Therefore, the soaking time is 10 to 180 seconds. The preferred lower limit of the soaking time is 15 seconds, more preferably 20 seconds. The preferred upper limit of the soaking time is 60 seconds, more preferably 40 seconds.
- the soaking time during the alloying process means the holding time of the steel sheet 2 at the above-mentioned maximum temperature.
- Cooling is carried out by a well-known method. Cooling is, for example, gas cooling. By gas cooling, for example, the temperature may be cooled from the maximum temperature at the time of alloying heat treatment to about 300 to 100 ° C.
- temper rolling process In the temper rolling step, temper rolling is performed on the steel sheet that has undergone alloying heat treatment. By appropriately setting the temper rolling conditions, the thickness, total elongation, press formability, yield strength, and the like of the surface-treated steel sheet 1 can be adjusted.
- the rolling reduction in temper rolling is, for example, 0.5 to 3.0%.
- the surface-treated steel sheet 1 of the present embodiment can be manufactured.
- the method for manufacturing the surface-treated steel sheet 1 of the present embodiment may include other steps in addition to the above steps.
- the other step is, for example, a pretreatment step.
- a pretreatment step may be performed before the Ni plating step.
- a pretreatment step may be performed before the Ni plating step.
- the surface of the prepared steel sheet 2 is subjected to alkaline degreasing and / or pickling to remove the oxide film and impurities on the surface of the steel sheet 2. This enhances the adhesion of the Ni plating layer. In addition, plating defects in the Ni plating layer can be reduced.
- the effect of the surface-treated steel sheet of the present embodiment will be described more specifically by way of examples.
- the conditions in the following examples are one condition example adopted for confirming the feasibility and effect of the surface-treated steel sheet of the present embodiment. Therefore, the surface-treated steel sheet of the present embodiment is not limited to this one condition example.
- Step sheet preparation process An aluminum killed steel steel plate having a thickness of 0.25 mm was prepared.
- the steel sheet has C: 0.0090%, Si: 0.006%, Mn: 0.12%, P: 0.012%, S: 0.0088%, sol. Al: 0.047%, N: 0.0025%, and the balance had a chemical composition consisting of Fe and impurities.
- the steel sheet was subjected to alkaline degreasing and pickling pretreatment.
- Ni plating process A Ni-plated layer was formed on the surface of the pretreated steel sheets of test numbers 1 to 12. The Ni plating layer was formed on both sides of the steel sheet. The obtained Ni plating layer was a plating layer composed of Ni and impurities. The Ni plating conditions for each test number are shown below.
- test numbers 1 to 11 a Co-plated layer was formed on the Ni-plated layer.
- the Co plating layer was formed on both sides of the steel sheet.
- the obtained Co plating layer was a plating layer composed of Co and impurities.
- the Co plating conditions of test numbers 1 to 11 are shown below.
- test number 12 a Co—Ni alloy plating layer containing Co and Ni was formed on the Ni plating layer.
- the Co—Ni alloy plating layer was formed on both sides of the steel sheet.
- the obtained Co—Ni alloy plating layer was a plating layer composed of Co, Ni and impurities.
- the Co—Ni alloy plating conditions of test number 12 are shown below.
- Ni content and Co content in Ni—Co—Fe alloy layer were measured by the following method. Elemental analysis was carried out on the Ni—Co—Fe alloy layer of the surface-treated steel sheet of each test number using a fluorescent X-ray analyzer.
- a fluorescent X-ray analyzer ZSX Primus II manufactured by Rigaku Co., Ltd. was used.
- the fluorescent X-ray analyzer prepared a calibration curve using a standard sample having a known Ni content and a standard sample having a known Co content.
- Ni content (g / m 2 ) and the Co content (g / m 2 ) in the Ni—Co—Fe alloy layer were determined. The results are shown in the "Ni content (g / m 2 )" column and the “Co content (g / m 2 )” column in Table 4.
- Ni concentration, Co concentration and Fe concentration measurement test by GDS The Ni concentration, Co concentration and Fe concentration in the Ni—Co—Fe alloy layer of the surface-treated steel sheet of each test number were measured by glow discharge spectroscopic analysis (GDS).
- GDS glow discharge spectroscopic analysis
- a high-frequency glow discharge emission surface analyzer manufactured by HORIBA, Ltd., model number: GD-Profiler2 was used for the measurement.
- the emission intensity of Ni (Intensity), the emission intensity of Co, and the emission intensity of Fe were converted into Ni content (mass%), Co content (mass%), and Fe content (mass%), respectively.
- the ratio of Ni (%), the ratio of Co (%) and the ratio of Fe where the sum of the obtained Ni content (% by mass), Co content (% by mass) and Fe content (% by mass) is 100%. Asked for (%).
- the obtained Ni ratio (%), Co ratio (%), and Fe ratio (%) were defined as Ni concentration (%), Co concentration (%), and Fe concentration (%), respectively.
- the measurement data having a depth of less than 0.006 ⁇ m (6 nm) converted from the Ar sputtering time may not always be able to accurately measure the Ni—Co—Fe alloy layer, it is removed from the analysis target and Ar. Only data having a depth of 0.006 ⁇ m or more converted from the spatter time was used.
- a point having a depth of 0.006 ⁇ m converted from the Ar sputtering time was defined as a depth of 0 ⁇ m.
- the GDS measurement conditions were as follows. H. V. : Fe is 785V, Ni is 630V, Co is 720V Anode diameter: ⁇ 4 mm Gas: Ar Gas pressure: 600Pa Output: 35W
- the graphs of the GDS analysis results of each test number are shown in FIGS. 1 to 2 and FIGS. 6 to 13.
- the vertical axis of each GDS chart shows the Ni concentration, the Co concentration and the Fe concentration.
- the horizontal axis of each GDS chart shows the distance (depth) ( ⁇ m) from the outermost surface of the Ni—Co—Fe alloy layer converted from the Ar sputter time.
- a graph of the GDS analysis result of test number 1 is shown in FIG.
- the graph of the GDS analysis result of the test number 2 is shown in FIG.
- a graph of the GDS analysis result of test number 3 is shown in FIG.
- the graph of the GDS analysis result of the test number 4 is shown in FIG.
- a graph of the GDS analysis result of test number 5 is shown in FIG. 2, FIG. 7, FIG. 9, FIG. 11 and FIG. 13 are enlarged views of the graphs of FIGS. 1, 6, 8, 10 and 12, respectively, in the range of 0 to 0.4 ⁇ m in depth.
- the Ni concentration on the outermost surface of the Ni—Co—Fe alloy layer is the Ni concentration at the initial depth at which the depth converted from the Ar sputtering time is 0.006 ⁇ m or more.
- the distance (Ni peak depth) from the outermost surface of the Ni—Co—Fe alloy layer to the position where the Ni concentration is maximum was determined. The results are shown in the column of "Ni peak depth ( ⁇ m)" in Table 4. Further, in the thickness direction of the Ni—Co—Fe alloy layer, the distance (Co peak depth) from the outermost surface of the Ni—Co—Fe alloy layer to the position ( PHCo ) where the Co concentration is maximum was determined.
- Ni-enriched region between the outermost surface of the Ni—Co—Fe alloy layer and the position where the Co concentration is maximum ( PHCo ) in the thickness direction of the Ni—Co—Fe alloy layer. If there is a Ni-enriched region between the outermost surface of the Ni—Co—Fe alloy layer and the position where the Co concentration is maximum ( PHCo ) in the thickness direction of the Ni—Co—Fe alloy layer, Ni It was judged that a concentrated region was formed. When “F” (Formed) is described in the "Ni-enriched region” column of Table 4, it means that the Ni-enriched region has been formed. On the other hand, when there is no Ni-concentrated region from the outermost surface of the Ni—Co—Fe alloy layer to the position where the Co concentration is maximum ( PHCo ) in the thickness direction of the Ni—Co—Fe alloy layer. , It was judged that the Ni-enriched region was not formed.
- Ni-enriched region When “N” (Not Formed) is described in the "Ni-enriched region” column of Table 4, it means that the Ni-enriched region was not formed. Further, in the thickness direction of the Ni—Co—Fe alloy layer 3, the position where the Ni concentration is lowest from the position where the Ni concentration is highest to the outermost surface of the Ni—Co—Fe alloy layer 3 and the position where the Ni concentration is lowest and Ni— A region between the outermost surface of the Co—Fe alloy layer 3 and a region in which the Ni concentration increases in the thickness direction of the Ni—Co—Fe alloy layer toward the outermost surface of the Ni—Co—Fe alloy layer. The distance in the thickness direction of the Ni—Co—Fe alloy layer was defined as the thickness ( ⁇ m) of the Ni-concentrated region. The results are shown in the column of "Thickness of Ni enriched region ( ⁇ m)" in Table 4.
- the surface charge transfer resistance was measured for the surface-treated steel sheet of each test number. Specifically, the surface-treated steel sheet of each test number was placed in a 35% KOH aqueous solution at 60 ° C. at 0.3 V vs. The constant potential was maintained at Hg / HgO for 10 days. 0.3V vs. Hg / HgO is the potential of manganese dioxide in the positive electrode of the manganese battery. The impedance value of the surface-treated steel sheet after holding the constant potential at a frequency of 0.1 Hz was measured. For the measurement, HZ-7000 manufactured by Hokuto Denko Co., Ltd. was used. The results are shown in Table 4.
- the surface-treated steel plates of test numbers 1 to 10 are Ni—Co—Fe alloys containing Ni, Co and Fe on the surface of the steel plate.
- the layer is provided, and in the thickness direction of the Ni—Co—Fe alloy layer, it is on the outermost surface side of the Ni—Co—Fe alloy layer from the position where the Ni concentration in the Ni—Co—Fe alloy layer is maximum, and The Co concentration in the Ni—Co—Fe alloy layer was maximized from the outermost surface of the Ni—Co—Fe alloy layer to a depth of 100 nm.
- the impedance value ( ⁇ ) of the surface-treated steel sheets of test numbers 1 to 10 is 50 ( ⁇ ) or less, and the color difference ( ⁇ E * ) before and after exposure to constant temperature and humidity conditions is 3.0 or less. there were.
- the surface-treated steel sheets of Test Nos. 1 to 10 had low contact resistance and were able to suppress surface discoloration.
- the impedance value ( ⁇ ) of the surface-treated steel sheets of test numbers 1 to 3 and 5 to 8 having a “Co / Ni ratio” of 3.0 or more was 10 ( ⁇ ) or less, and the contact resistance was further low. ..
- the color difference ( ⁇ E * ) of the surface-treated steel sheets of test numbers 1 to 9 having the “outermost surface Ni concentration (%)” of 20 (%) or more was 2.5 or less, and the discoloration of the surface could be further suppressed. ..
- the surface-treated steel sheet of Test No. 11 is provided with a Ni—Co—Fe alloy layer containing Ni, Co and Fe on the surface of the steel sheet, and Ni—Co—in the thickness direction of the Ni—Co—Fe alloy layer.
- Ni-Co is on the outermost surface side of the Ni—Co—Fe alloy layer from the position where the Ni concentration is maximum in the Fe alloy layer, and from the outermost surface of the Ni—Co—Fe alloy layer to a depth of 100 nm. -The Co concentration in the Fe alloy layer became the maximum.
- the surface-treated steel sheet of test number 12 was too deep at the position where the Co concentration was maximum in the Ni—Co—Fe alloy layer. Specifically, the Co concentration in the Ni—Co—Fe alloy layer became maximum at a depth of 400 nm from the outermost surface of the Ni—Co—Fe alloy layer. As a result, the impedance value ( ⁇ ) of the surface-treated steel sheet of Test No. 12 was 160, and the contact resistance was high.
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Abstract
Description
鋼板と、
前記鋼板表面に、Ni、Co及びFeを含有するNi-Co-Fe合金層とを備え、
前記Ni-Co-Fe合金層の厚さ方向において、前記Ni-Co-Fe合金層中のNi濃度が最大となる位置よりも前記Ni-Co-Fe合金層の最表面側で、かつ、前記Ni-Co-Fe合金層の最表面から深さ100nmまでの間で前記Ni-Co-Fe合金層中のCo濃度が最大となり、
前記Ni-Co-Fe合金層は、
前記Ni-Co-Fe合金層の最表面から前記Co濃度が最大となる位置までの間に、前記Ni-Co-Fe合金層の最表面に向かって前記Ni濃度が増加するNi濃化領域を含む。
鋼板と、
前記鋼板表面に、Ni、Co及びFeを含有するNi-Co-Fe合金層とを備え、
前記Ni-Co-Fe合金層の厚さ方向において、前記Ni-Co-Fe合金層中のNi濃度が最大となる位置よりも前記Ni-Co-Fe合金層の最表面側で、かつ、前記Ni-Co-Fe合金層の最表面から深さ100nmまでの間で前記Ni-Co-Fe合金層中のCo濃度が最大となり、
前記Ni-Co-Fe合金層は、
前記Ni-Co-Fe合金層の最表面から前記Co濃度が最大となる位置までの間に、前記Ni-Co-Fe合金層の最表面に向かって前記Ni濃度が増加するNi濃化領域を含む、表面処理鋼板。
[1]に記載の表面処理鋼板であって、
前記Ni-Co-Fe合金層の厚さ方向において、前記Co濃度が最大となる位置における、前記Ni濃度に対する前記Co濃度の比が、3.0以上である、表面処理鋼板。
[1]又は[2]に記載の表面処理鋼板であって、
前記鋼板の片面当たりの、前記Ni-Co-Fe合金層中のNi含有量が1.34~5.36g/m2であり、前記Ni-Co-Fe合金層中のCo含有量が0.45~1.34g/m2である、表面処理鋼板。
[1]又は[2]に記載の表面処理鋼板であって、
前記鋼板の片面当たりの、前記Ni-Co-Fe合金層中のNi含有量が5.36~35.6g/m2であり、前記Ni-Co-Fe合金層中のCo含有量が0.45~1.34g/m2である、表面処理鋼板。
本実施形態の表面処理鋼板は、鋼板と、鋼板表面に、Ni、Co及びFeを含有するNi-Co-Fe合金層3とを備える。図3は、本実施形態の表面処理鋼板の一例を示す断面図である。図3を参照して、本実施形態の表面処理鋼板1は、鋼板2と、Ni-Co-Fe合金層3とを備える。Ni-Co-Fe合金層3は、鋼板2の表面に配置される。図3では、Ni-Co-Fe合金層3は鋼板2の両面に配置されている。しかしながら、Ni-Co-Fe合金層3の配置は、図3に限定されない。Ni-Co-Fe合金層3は、図4に示すとおり、鋼板2の片面のみに配置されてもよい。
本実施形態の表面処理鋼板1の厚さは特に限定されないが、たとえば0.05~1.5mmである。アルカリ電池等の電池用途ではたとえば、0.1~1.0mmである。表面処理鋼板1の厚さは周知の方法で測定できる。表面処理鋼板1の厚さはたとえば、マイクロメータによって測定する。
Ni-Co-Fe合金層3は、Ni、Co及びFeを含有する。Ni、Co及びFeはそれぞれ、Ni-Co-Fe合金層3の厚さ方向において、部分的に存在してもよく、全体にわたって存在しても良い。つまり、本実施形態の表面処理鋼板1において、Ni-Co-Fe合金層3の厚さ方向の全域に、Ni、Co及びFeが常に含有されていなくてもよい。
Ni-Co-Fe合金層3の厚さは特に限定されず、用途に応じて適宜設定される。Ni-Co-Fe合金層3の厚さはたとえば、0.1~10.0μmである。アルカリ電池用途の場合は、Ni-Co-Fe合金層3の厚さはたとえば、0.1~5.0μmである。
Ni-Co-Fe合金層3は次の方法で特定する。表面処理鋼板1の表面から、表面処理鋼板1の厚さ方向に、グロー放電分光分析法(GDS)によって、Ni濃度、Co濃度及びFe濃度を測定する。測定には、高周波グロー放電発光表面分析装置(堀場製作所製、型番:GD-Profiler2)を用いる。Niの発光強度(Intensity)、Coの発光強度及びFeの発光強度をそれぞれNi含有量(質量%)、Co含有量(質量%)及びFe含有量(質量%)に換算する。得られたNi含有量(質量%)、Co含有量(質量%)及びFe含有量(質量%)の和を100%として、Niの割合(%)、Coの割合(%)及びFeの割合(%)を求める。得られたNiの割合(%)、Coの割合(%)及びFeの割合(%)をそれぞれNi濃度(%)、Co濃度(%)及びFe濃度(%)とする。GDS測定条件は次のとおりとする。
H.V.:Feが785V、Niが630V、Coが720V
アノード径:φ4mm
ガス:Ar
ガス圧力:600Pa
出力:35W
図2を参照して、Ni-Co-Fe合金層3は、Ni濃化領域4を含む。Ni濃化領域4とは、Ni-Co-Fe合金層3の厚さ方向において、Ni濃度が最も高くなる位置(PHNi)からNi-Co-Fe合金層3の最表面までの間でNi濃度が最も低くなる位置(PLNi)と、Ni-Co-Fe合金層3の最表面との間の領域であって、Ni-Co-Fe合金層3の最表面に向かってNi濃度が増加する領域をいう。本実施形態においては、Ni濃化領域4が、Ni-Co-Fe合金層3の最表面からCo濃度が最大となる位置(PHCo)までの間に位置する。これにより、Ni-Co-Fe合金層3の最表面の近傍のNi濃度を高めることができる。その結果、Ni-Co-Fe合金層3の表層のCoの酸化が抑制され、表面処理鋼板の表面の変色を抑制できる。なお、Ni濃化領域4内の最大のNi濃度は、Ni-Co-Fe合金層3中の最大のNi濃度よりも低い。
Ni濃化領域4の厚さが0.01μm以上であれば、Ni-Co-Fe合金層3の最表面の近傍のNi濃度を安定して高めることができる。その結果、Ni-Co-Fe合金層3のCoの酸化をより安定して抑制できる。一方、Ni濃化領域4の厚さが0.15μm以下であれば、Ni-Co-Fe合金層表層のCo濃度が相対的に高く保たれる。その結果、表面処理鋼板1の接触抵抗をより安定して低くできる。したがって、Ni濃化領域4の厚さは、0.01~0.15μmであることが好ましい。Ni濃化領域4の厚さの下限は、より好ましくは0.02μmであり、さらに好ましくは0.03μmであり、さらに好ましくは0.04μmであり、さらに好ましくは0.05μmであり、さらに好ましくは0.06μmである。Ni濃化領域4の厚さの上限は、より好ましくは0.12μmであり、さらに好ましくは0.11μmであり、さらに好ましくは0.10μmであり、さらに好ましくは0.09μmであり、さらに好ましくは0.08μmであり、さらに好ましくは0.07μmであり、さらに好ましくは0.06μmである。
Ni濃化領域4の厚さは、次の方法で測定する。まず、表面処理鋼板1に対して、上述の方法でGDS測定を行う。Ni-Co-Fe合金層3の厚さ方向において、Ni濃度が最も高くなる位置(PHNi)からNi-Co-Fe合金層3の最表面までの間でNi濃度が最も低くなる位置(PLNi)と、Ni-Co-Fe合金層3の最表面との間の領域であって、Ni-Co-Fe合金層3の最表面に向かってNi濃度が増加する領域を特定する。この領域の厚さをNi濃化領域4の厚さ(μm)とする。つまり、上記のNi濃度が極小値となる位置(PLNi)からNi-Co-Fe合金層3の最表面までの、Ni-Co-Fe合金層3の厚さ方向の距離をNi濃化領域4の厚さ(μm)とする。
Ni-Co-Fe合金層3の最表面のNi濃度が10%以上であれば、表面処理鋼板1の変色をより安定して抑制できる。一方、Ni-Co-Fe合金層3の最表面のNi濃度が90%以下であれば、表面処理鋼板1の低い接触抵抗をより安定して維持できる。したがって、Ni-Co-Fe合金層3の最表面のNi濃度は、10~90%であることが好ましい。Ni-Co-Fe合金層3の最表面のNi濃度の下限は、より好ましくは20%、さらに好ましくは30%である。Ni-Co-Fe合金層3の最表面のNi濃度の上限は、より好ましくは80%、さらに好ましくは70%であり、さらに好ましくは60%であり、さらに好ましくは55%である。
好ましくは、Ni-Co-Fe合金層3の厚さ方向においてCo濃度が最大となる位置(PHCo)における、Ni濃度に対するCo濃度の比は、0.5以上である。Co濃度が最大となる位置(PHCo)における、Ni濃度に対するCo濃度の比が高ければ、表面処理鋼板1の接触抵抗を低いまま維持しやすい。したがって、Ni-Co-Fe合金層3の厚さ方向においてCo濃度が最大となる位置(PHCo)における、Ni濃度に対するCo濃度の比の下限はより好ましくは1.0であり、さらに好ましくは2.0であり、さらに好ましくは3.0であり、さらに好ましくは4.0であり、さらに好ましくは5.0であり、さらに好ましくは5.5である。Ni-Co-Fe合金層の厚さ方向においてCo濃度が最大となる位置(PHCo)における、Ni濃度に対するCo濃度の比の上限は好ましくは10.0であり、より好ましくは9.5であり、さらに好ましくは9.0である。
Co濃度/Ni濃度比は、次の方法で測定する。まず、上述の方法でGDS測定を行う。Ni-Co-Fe合金層の厚さ方向においてCo濃度が最大となる位置(PHCo)における、Ni濃度及びCo濃度を測定する。得られたCo濃度をNi濃度で除して、Co濃度/Ni濃度比を算出する。
好ましくは、鋼板2の片面当たりのNi-Co-Fe合金層3中のNi含有量及びCo含有量は次のとおりである。
Ni-Co-Fe合金層3中のNi含有量が1.34g/m2以上であれば、表面処理鋼板1の防錆性が高まる。一方、Ni-Co-Fe合金層3中のNi含有量が35.6g/m2を超えても、表面処理鋼板1の防錆性は飽和する。Ni-Co-Fe合金層3中のNi含有量が35.6g/m2以下であればコストを抑制できる。したがって、Ni-Co-Fe合金層3中のNi含有量は好ましくは1.34~35.6g/m2である。Ni-Co-Fe合金層3中のNi含有量のより好ましい下限は5.36g/m2であり、さらに好ましくは8.93g/m2である。Ni-Co-Fe合金層3中のNi含有量のより好ましい上限は26.8g/m2であり、さらに好ましくは17.9g/m2である。
Ni-Co-Fe合金層3中のCo含有量が0.45g/m2以上であれば、表面処理鋼板1の接触抵抗を低いまま維持しやすい。一方、Ni-Co-Fe合金層3中のCo含有量が1.34g/m2以下であれば、Ni-Co-Fe合金層3のアルカリ電解液に対する耐溶解性が高まる。したがって、Ni-Co-Fe合金層3中のCo含有量は好ましくは0.45~1.34g/m2である。Ni-Co-Fe合金層3中のCo含有量のより好ましい下限は0.54g/m2であり、さらに好ましくは0.63g/m2である。Ni-Co-Fe合金層3中のCo含有量のより好ましい上限は1.11g/m2であり、さらに好ましくは0.89g/m2である。
全拡散の場合、好ましくは、鋼板2の片面当たりのNi-Co-Fe合金層3中のNi含有量及びCo含有量は次のとおりである。
Ni-Co-Fe合金層3中のNi含有量が1.34g/m2以上であれば、表面処理鋼板1の防錆性が高まる。一方、Ni-Co-Fe合金層3中のNi含有量が5.36g/m2以下であれば、Ni-Co-Fe合金層3の最表面までFeが拡散しやすい。したがって、Ni-Co-Fe合金層3を全拡散とする場合は、Ni-Co-Fe合金層3中のNi含有量は好ましくは1.34~5.36g/m2である。全拡散の場合、Ni-Co-Fe合金層3中のNi含有量のより好ましい下限は2.23g/m2であり、さらに好ましくは3.12g/m2である。全拡散の場合、Ni-Co-Fe合金層3中のNi含有量のより好ましい上限は4.45g/m2であり、さらに好ましくは3.56g/m2である。
Ni-Co-Fe合金層3中のCo含有量が0.45g/m2以上であれば、表面処理鋼板1の接触抵抗を低いまま維持しやすい。一方、Ni-Co-Fe合金層3中のCo含有量が1.34g/m2以下であれば、Ni-Co-Fe合金層3のアルカリ電解液に対する耐溶解性が高まる。したがって、全拡散の場合のNi-Co-Fe合金層3中のCo含有量は好ましくは0.45~1.34g/m2である。全拡散の場合のNi-Co-Fe合金層3中のCo含有量のより好ましい下限は0.54g/m2であり、さらに好ましくは0.63g/m2である。全拡散の場合のNi-Co-Fe合金層3中のCo含有量のより好ましい上限は1.11g/m2であり、さらに好ましくは0.89g/m2である。
部分拡散の場合、好ましくは、鋼板2の片面当たりのNi-Co-Fe合金層3中のNi含有量及びCo含有量は次のとおりである。
Ni-Co-Fe合金層3中のNi含有量が5.36g/m2以上であれば、部分拡散のNi-Co-Fe合金層3を製造し易い。一方、Ni-Co-Fe合金層3中のNi含有量が35.6g/m2以下であればコストを抑制できる。したがって、Ni-Co-Fe合金層3を部分拡散とする場合は、Ni-Co-Fe合金層3中のNi含有量は好ましくは5.36~35.6g/m2である。部分拡散の場合、Ni-Co-Fe合金層3中のNi含有量のより好ましい下限は8.93g/m2であり、さらに好ましくは17.9g/m2である。部分拡散の場合、Ni-Co-Fe合金層3中のNi含有量のより好ましい上限は31.3g/m2であり、さらに好ましくは22.3g/m2である。
Ni-Co-Fe合金層3中のCo含有量が0.45g/m2以上であれば、表面処理鋼板1の接触抵抗を低いまま維持しやすい。一方、Ni-Co-Fe合金層3中のCo含有量が1.34g/m2以下であれば、Ni-Co-Fe合金層3のアルカリ電解液に対する耐溶解性が高まる。したがって、部分拡散の場合のNi-Co-Fe合金層3中のCo含有量はより好ましくは0.45~1.34g/m2である。部分拡散の場合のNi-Co-Fe合金層3中のCo含有量のより好ましい下限は0.54g/m2であり、さらに好ましくは0.63g/m2である。部分拡散の場合のNi-Co-Fe合金層3中のCo含有量のより好ましい上限は1.11g/m2であり、さらに好ましくは0.89g/m2である。
Ni-Co-Fe合金層3中のNi含有量及びCo含有量は次の方法で測定する。まず、Ni-Co-Fe合金層3を備える表面処理鋼板1を準備する。次に、表面処理鋼板1のNi-Co-Fe合金層3に対して蛍光X線分析装置を用いて元素分析を実施する。蛍光X線分析装置は、事前にNi含有量が既知の標準サンプル、及び、Co含有量が既知の標準サンプルを用いて検量線を作成しておく。この検量線に基づき、Ni-Co-Fe合金層3中のNi含有量(g/m2)及びCo含有量(g/m2)を求める。
本実施形態の表面処理鋼板1のインピーダンス値(Ω)は、好ましくは50(Ω)以下である。ここで、インピーダンス値(Ω)とは、表面処理鋼板1を、60℃の35%KOH水溶液中に0.3V vs.Hg/HgOで10日間定電位保持した後測定された、周波数0.1Hz時のインピーダンス値(Ω)をいう。インピーダンス値(Ω)の上限はより好ましくは45であり、さらに好ましくは40であり、さらに好ましくは30であり、さらに好ましくは20であり、さらに好ましくは10であり、さらに好ましくは5である。インピーダンス値(Ω)の下限は特に限定されないが、たとえば1である。
本実施形態の表面処理鋼板1の(ΔE*)は、好ましくは3.0以下である。ここで、色差(ΔE*)とは、表面処理鋼板1を、温度:60℃、湿度:90%RHで240時間保持する前後のL*a*b*値から求めた色差(ΔE*)をいう。色差(ΔE*)の上限はより好ましくは2.9であり、さらに好ましくは2.7であり、さらに好ましくは2.5であり、さらに好ましくは2.3であり、さらに好ましくは2.1であり、さらに好ましくは2.0であり、さらに好ましくは1.9であり、さらに好ましくは1.6である。色差(ΔE*)の下限は特に限定されないが、たとえば0である。
鋼板2の化学組成は特に限定されない。鋼板2はたとえば、炭素(C)を0.25質量%以下含有する低炭素鋼、Cを0.01質量%未満含有する極低炭素鋼及び、極低炭素鋼にTi及びNbを含有させて得られる非時効性極低炭素鋼からなる群から選択されてもよい。鋼板2は、冷延鋼板であってもよい。低炭素鋼の冷延鋼板がたとえば、JIS(Japanese Industrial Standards)G3141(2017)の、SPCC、SPCD、SPCE、SPCF及びSPCGとして規定されている。鋼板2はこれらの冷延鋼板であってもよい。また、鋼板2は、アルミキルド鋼であってもよい。
上述の本実施形態の表面処理鋼板1の製造方法を説明する。以降に説明する表面処理鋼板1の製造方法は、本実施形態の表面処理鋼板1の製造方法の一例である。したがって、上述の構成を有する表面処理鋼板1は、以降に説明する製造方法以外の他の製造方法により製造されてもよい。しかしながら、以降に説明する製造方法は、本実施形態の表面処理鋼板1の製造方法の好ましい一例である。
鋼板準備工程では、上述の鋼板2を準備する。鋼板2は、第三者から供給されてもよいし、製造してもよい。鋼板2を製造する場合たとえば、次の方法により製造する。上述の化学組成を有する溶鋼を製造する。製造された溶鋼を用いて、鋳片を製造する。製造された鋳片に対して、熱間圧延、酸洗及び冷間圧延を実施する。冷間圧延後に焼鈍及び調質圧延を実施してもよい。以上の工程により、鋼板2を製造できる。鋼板2の厚さは特に限定されず、表面処理鋼板1の用途に応じて選択される。鋼板2の厚さはたとえば、0.05~1.5mmである。アルカリ電池等の電池用途ではたとえば、0.1~1.0mmである。
Niめっき工程では、鋼板2の表面にNi及び不純物からなるNiめっき層を形成する。具体的には、鋼板2をNiめっき浴に接触させて、電解めっき又は無電解めっきを実施する。鋼板2をNiめっき浴に浸漬して、電解めっきを実施してもよい。Niめっき浴は周知のNiめっき浴を使用できる。Niめっき浴はたとえば、ワット浴、硫酸浴、スルファミン酸浴、ウッド浴、ホウフッ化物浴、塩化物浴及びクエン酸浴からなる群から選択される。Niめっき浴は、Niイオンを含有する。Niイオンの含有量はたとえば0.5~2.0mol/Lである。Niイオンは、硫酸ニッケル、硫酸ニッケルアンモニウム、塩化ニッケル及びスルファミン酸ニッケルからなる群から選択される1種以上としてNiめっき浴に添加されてもよい。Niめっき浴は、Niイオンの他に、他の成分を含有してもよい。他の成分とはたとえば、ホウ酸、塩酸、チオシアン酸ナトリウム、クエン酸、光沢剤、pH調整剤及び界面活性剤からなる群から選択される1種以上である。他の成分は、Niめっき浴の種類に応じて適宜設定される。
Coめっき工程では、Niめっき層上にCo及び不純物からなるCoめっき層を形成する。具体的には、鋼板2表面のNiめっき層をCoめっき浴に接触させて、電解めっきを実施する。Niめっき層を備える鋼板2をCoめっき浴に浸漬して、電解めっきを実施してもよい。Coめっき浴は市販のCoめっき浴を使用できる。Coめっき浴は、Coイオンを含有する。Coイオンの含有量はたとえば、0.5~2.0mol/Lである。Coイオンは、硫酸コバルト及び塩化コバルトからなる群から選択される1種以上としてCoめっき浴に添加されてもよい。Coめっき浴は、Coイオンの他に、他の成分を含有してもよい。他の成分とはたとえば、ギ酸、ホウ酸、塩酸、チオシアン酸ナトリウム、クエン酸、光沢剤、pH調整剤及び界面活性剤からなる群から選択される1種以上である。他の成分は、Coめっき浴の種類に応じて適宜設定される。
これにより、Niめっき層上にCoめっき層が形成できる。
合金化熱処理工程では、Niめっき層及びCoめっき層を備える鋼板2を合金化熱処理する。合金化熱処理により、Niめっき層中のNi、Coめっき層中のCo及び鋼板2に含まれるFeが相互に拡散して、Ni-Co-Fe合金層3が形成される。合金化熱処理炉は周知の加熱炉を使用できる。合金化熱処理では、連続的に鋼板2を加熱炉に供給して実施する。
合金化熱処理時の最高温度が630℃未満であれば、Niめっき層中のNi、Coめっき層中のCo及び鋼板2に含まれるFeの相互拡散が不十分となる。この場合、Ni-Co-Fe合金層3の密着性が低下する。一方、合金化熱処理時の最高温度が860℃超であれば、鋼板2の硬度が低下する。したがって、合金化熱処理時の処理温度は630~860℃である。合金化熱処理時の処理温度の好ましい下限は720℃であり、より好ましくは760℃である。合金化熱処理時の処理温度の好ましい上限は830℃であり、より好ましくは810℃である。ここで、合金化熱処理時の最高温度とは、加熱炉内で鋼板2が到達する最高の温度をいう。
合金化熱処理時の露点が-25℃未満であれば、Ni-Co-Fe合金層3の最表面からCo濃度が最大となる位置(PHCo)までの間に、Ni濃化領域4を形成できない。したがって、合金化熱処理時の露点は-25℃以上である。合金化熱処理時の好ましい露点の下限は-20℃であり、より好ましくは-10℃である。合金化熱処理時の露点の上限は特に限定されないが、たとえば5℃であり、好ましくは0℃未満である。合金化熱処理時の露点が0℃未満であれば、表面処理鋼板1の表面において相対的にCo濃度を高くできる。その結果、表面処理鋼板1の接触抵抗をさらに低くできる。
合金化処理時の均熱時間が10秒未満であれば、Niめっき層中のNi、Coめっき層中のCo及び鋼板2に含まれるFeの相互拡散が不十分となる。この場合、Ni-Co-Fe合金層3の密着性が低下する。一方、合金化処理時の均熱時間が180秒超であれば、鋼板2の硬度が低下する。したがって、均熱時間は10~180秒である。均熱時間の好ましい下限は15秒であり、より好ましくは20秒である。均熱時間の好ましい上限は60秒であり、より好ましくは40秒である。ここで、合金化処理時の均熱時間とは、鋼板2の上記最高温度での保持時間をいう。
調質圧延工程では、合金化熱処理を実施した鋼板に対して調質圧延を実施する。調質圧延条件を適宜設定することにより、表面処理鋼板1の厚さ、全伸び(Elongation)、プレス成形性及び降伏強度等を調整できる。調質圧延における圧下率はたとえば、0.5~3.0%である。
その他の工程とはたとえば、前処理工程である。Niめっき工程の前に前処理工程を実施してもよい。
Niめっき工程の前に前処理工程を実施してもよい。前処理工程では、準備された鋼板2の表面に対して、アルカリ脱脂及び/又は酸洗を実施し、鋼板2の表面の酸化皮膜及び不純物を除去する。これにより、Niめっき層の密着性が高まる。また、Niめっき層のめっき不良が低減できる。
厚さ0.25mmのアルミキルド鋼の鋼板を準備した。鋼板はC:0.0090%、Si:0.006%、Mn:0.12%、P:0.012%、S:0.0088%、sol.Al:0.047%、N:0.0025%、及び、残部はFe及び不純物からなる化学組成を有した。鋼板に対して、アルカリ脱脂及び酸洗の前処理を実施した。
前処理を実施した試験番号1~12の鋼板の表面に、Niめっき層を形成した。Niめっき層は、鋼板の両面に形成した。得られたNiめっき層は、Ni及び不純物からなるめっき層であった。各試験番号のNiめっき条件を、次に示す。
試験番号1~11では、Niめっき層上にCoめっき層を形成した。Coめっき層は、鋼板の両面に形成した。得られたCoめっき層は、Co及び不純物からなるめっき層であった。試験番号1~11のCoめっき条件を、次に示す。
Niめっき層及びCoめっき層、又は、Niめっき層及びCo-Ni合金めっき層を備える鋼板に対して連続合金化熱処理を実施した。合金化熱処理は以下の条件で実施した。各試験番号の詳細な合金化熱処理条件を、表4に示す。
最高温度:640~830℃
露点:-30~0℃
雰囲気:N2+2%H2
均熱時間:20~120秒
冷却:100℃までN2ガス冷却
合金化熱処理後の鋼板に対して調質圧延を実施した。調質圧延の圧下率は1.5%であった。以上の工程により、各試験番号の表面処理鋼板1を製造した。
各試験番号の表面処理鋼板のNi-Co-Fe合金層中のNi含有量及びCo含有量を次の方法で測定した。各試験番号の表面処理鋼板のNi-Co-Fe合金層に対して蛍光X線分析装置を用いて元素分析を実施した。蛍光X線分析装置は、株式会社リガク製ZSX Primus IIを使用した。蛍光X線分析装置は、事前にNi含有量が既知の標準サンプル、及び、Co含有量が既知の標準サンプルを用いて検量線を作成した。この検量線に基づき、Ni-Co-Fe合金層中のNi含有量(g/m2)及びCo含有量(g/m2)を求めた。結果を表4の「Ni含有量(g/m2)」の欄、及び、「Co含有量(g/m2)」の欄に示す。
グロー放電分光分析法(GDS)によって、各試験番号の表面処理鋼板のNi-Co-Fe合金層中のNi濃度、Co濃度及びFe濃度を測定した。測定には、高周波グロー放電発光表面分析装置(株式会社堀場製作所製、型番:GD-Profiler2)を用いた。Niの発光強度(Intensity)、Coの発光強度及びFeの発光強度をそれぞれNi含有量(質量%)、Co含有量(質量%)及びFe含有量(質量%)に換算した。得られたNi含有量(質量%)、Co含有量(質量%)及びFe含有量(質量%)の和を100%として、Niの割合(%)、Coの割合(%)及びFeの割合(%)を求めた。得られたNiの割合(%)、Coの割合(%)及びFeの割合(%)をそれぞれNi濃度(%)、Co濃度(%)及びFe濃度(%)とした。ここで、Arスパッタ時間から換算した深さが0.006μm(6nm)未満の測定データは必ずしもNi-Co-Fe合金層を正確に測定できていないこともあるため、解析対象から除去し、Arスパッタ時間から換算した深さが0.006μm以上のデータのみを使用した。Arスパッタ時間から換算した深さが、0.006μmの点を深さ0μmとした。GDS測定条件は次のとおりとした。
H.V.:Feが785V、Niが630V、Coが720V
アノード径:φ4mm
ガス:Ar
ガス圧力:600Pa
出力:35W
各試験番号の表面処理鋼板に対して、表面の電荷移動抵抗を測定した。具体的には、各試験番号の表面処理鋼板を、60℃の35%KOH水溶液中に0.3V vs.Hg/HgOで10日間定電位保持した。0.3V vs.Hg/HgOは、マンガン電池の正極における二酸化マンガンの電位である。定電位保持後の表面処理鋼板に対して、周波数0.1Hz時のインピーダンス値を測定した。測定には、北斗電工株式会社製のHZ-7000を使用した。結果を表4に示す。
各試験番号の表面処理鋼板を恒温恒湿試験機(エスペック株式会社製、型番LH)内に入れ、温度:60℃、湿度:90%RHで240時間保持した。恒温恒湿保持する前後の表面処理鋼板のL*a*b*値を測定した。測定には、分光測色計(コニカミノルタ製CM-700d)を用いた。測定条件は、測定径:φ8mm、SCE、D65光、2°視野であった。恒温恒湿保持する前後のL*a*b*値から、色差(ΔE*)を求めた。結果を表4に示す。
表4及び図1~図2、及び、図6~図13を参照して、試験番号1~10の表面処理鋼板は、鋼板表面に、Ni、Co及びFeを含有するNi-Co-Fe合金層を備え、Ni-Co-Fe合金層の厚さ方向において、Ni-Co-Fe合金層中のNi濃度が最大となる位置よりもNi-Co-Fe合金層の最表面側で、かつ、Ni-Co-Fe合金層の最表面から深さ100nmまでの間でNi-Co-Fe合金層中のCo濃度が最大となった。試験番号1~10の表面処理鋼板ではさらに、Ni-Co-Fe合金層の最表面からCo濃度が最大となる位置までの間に、Ni濃化領域が形成されていた。その結果、試験番号1~10の表面処理鋼板のインピーダンス値(Ω)は50(Ω)以下であり、かつ、恒温恒湿条件に曝される前後の色差(ΔE*)が3.0以下であった。試験番号1~10の表面処理鋼板は、接触抵抗が低く、かつ、表面の変色を抑制可能であった。
2 鋼板
3 Ni-Co-Fe合金層
4 Ni濃化領域
10 正極(二酸化マンガン)
11 負極(亜鉛)
12 セパレーター
13 集電体
14 絶縁体
15 正極端子
Claims (4)
- 鋼板と、
前記鋼板表面に、Ni、Co及びFeを含有するNi-Co-Fe合金層とを備え、
前記Ni-Co-Fe合金層の厚さ方向において、前記Ni-Co-Fe合金層中のNi濃度が最大となる位置よりも前記Ni-Co-Fe合金層の最表面側で、かつ、前記Ni-Co-Fe合金層の最表面から深さ100nmまでの間で前記Ni-Co-Fe合金層中のCo濃度が最大となり、
前記Ni-Co-Fe合金層は、
前記Ni-Co-Fe合金層の最表面から前記Co濃度が最大となる位置までの間に、前記Ni-Co-Fe合金層の最表面に向かって前記Ni濃度が増加するNi濃化領域を含む、表面処理鋼板。 - 請求項1に記載の表面処理鋼板であって、
前記Ni-Co-Fe合金層の厚さ方向において、前記Co濃度が最大となる位置における、前記Ni濃度に対する前記Co濃度の比が、3.0以上である、表面処理鋼板。 - 請求項1又は請求項2に記載の表面処理鋼板であって、
前記鋼板の片面当たりの、前記Ni-Co-Fe合金層中のNi含有量が1.34~5.36g/m2であり、前記Ni-Co-Fe合金層中のCo含有量が0.45~1.34g/m2である、表面処理鋼板。 - 請求項1又は請求項2に記載の表面処理鋼板であって、
前記鋼板の片面当たりの、前記Ni-Co-Fe合金層中のNi含有量が5.36~35.6g/m2であり、前記Ni-Co-Fe合金層中のCo含有量が0.45~1.34g/m2である、表面処理鋼板。
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