EP4653584A1

EP4653584A1 - Nickel-plated metal material

Info

Publication number: EP4653584A1
Application number: EP24744662.8A
Authority: EP
Inventors: Yuhei HAMAOKA; Koh Yoshioka; Kyoko Takano
Original assignee: Toyo Kohan Co Ltd
Current assignee: Toyo Kohan Co Ltd
Priority date: 2023-01-16
Filing date: 2024-01-16
Publication date: 2025-11-26
Also published as: EP4653586A1; KR20250135770A; JPWO2024154742A1; JPWO2024154741A1; CN120476229A; WO2024154742A1; KR20250135771A; CN120418481A; CN120500558A; KR20250136307A; WO2024154741A1; JPWO2024154743A1; WO2024154743A1; EP4653585A1

Abstract

Disclosed is a nickel-plated metal material excellent in shear durability (adhesion between a base material and a roughed nickel layer when loads are applied from multiple directions to the roughened nickel layer), while having adhesion of a plating layer with the base material and adhesion with another member.[Solving Means]The nickel-plated metal material includes a base material made of metal, and a roughened nickel layer formed on at least one side on the base material. On a surface on a side of the roughened nickel layer, a root mean square height Rq is 0.29 µm or greater and 0.90 µm or smaller, and a maximum height Sz is greater than 3.5 µm and 10.0 µm or smaller.

Description

[Technical Field]

The present invention relates to a nickel-plated metal material.

[Background Art]

In recent years, in a technology that forms a plating layer on a base material such as a metal sheet or a metal foil, techniques are not limited to smoothly forming a plating layer, but are known to form roughness on the plating surface or to deposit metal in a granular or acicular form on a base material, that is, to form what is called a roughened plating layer.
For example, PTL 1 discloses a roughened nickel-plated sheet, the lightness and 85°-gloss of a surface of a roughened nickel layer of which are specified to provide the roughened nickel-plated sheet with excellent adhesion with another member while allowing the plating layer to hold adhesion with a base material. Further, PTL 2 discloses a roughened nickel-plated sheet improved in liquid penetration resistance when joined with another member, in addition to the adhesion of a plating layer to a base material and adhesion with another member.

[Citation List]

[Patent Literature]

[PTL 1]
PCT Patent Publication No. WO2020/017655
[PTL 2]
PCT Patent Publication No. WO2021/149821

[Summary]

[Technical Problem]

With respect to the roughened nickel steel sheet disclosed in the above-described PTL 1 and PTL 2, studies have been made to provide both adhesion of the roughened nickel layer with the base material (hereinafter also called "plating adhesion") and adhesion with another member by the roughened nickel layer. On an occasion that a metal sheet having a roughened nickel layer was industrially manufactured, on the other hand, an event, in which loads unexpected in the above-described PTL 1 and PTL 2 were applied to the roughened nickel layer, was observed in a manufacturing line after the formation of the roughened nickel layer on the base material. Specifically, during rolling on an occasion that a roughened nickel metal sheet is industrially and continuously manufactured or in a continuous manufacturing step using a roughened nickel metal sheet such as stacking it with another member such as, for example, a molten resin, loads are applied from multiple directions to a roughened nickel layer. From the viewpoints of product quality, suppression of consumption of manufacturing facilities and suppression of resources and energy losses, it is hence preferred for a plated metal sheet having a roughened nickel layer to have a roughened shape with durability to such loads from multiple directions (hereinafter also called "shear durability").
The present invention has been made with a view to solving such a problem, and has, as an object thereof, the provision of a nickel-plated metal sheet including a roughened nickel layer having shear durability to loads from multiple directions.

[Solution to Problem]

To solve the above-described problem, a nickel-plated metal material in the present embodiment is (1) a nickel-plated metal material including a base material made of metal, and a roughened nickel layer formed on at least one side on the base material. On a surface of the nickel-plated metal material, the surface being on a side of the roughened nickel layer, a root mean square height Rq is 0.29 µm or greater and 0.90 µm or smaller, and a maximum height Sz is greater than 3.5 µm and 10.0 µm or smaller.
In (1) described above, (2) Sdr (Developed Interfacial Area Ratio) on the surface on the side of the roughened nickel layer is preferably 16% to 75%.
In (1) or (2) described above, (3) a relative load length ratio Rmr on the surface on the side of the roughened nickel layer is preferably 33% to 95%.
In any one of (1) to (3) described above, (4) a root mean square slope RΔq on the surface on the side of the roughened nickel layer is preferably 15 to 50 degrees.
In any one of (1) to (4) described above, (5) a ten-point mean roughness Rzjis on the surface on the side of the roughened nickel layer is preferably 1.0 to 6.0 µm.
In any one of (1) to (5) described above, (6) a deposition amount of nickel in the roughened nickel layer is preferably 3.5 to 19.0 g/m².
In any one of (1) to (6) described above, (7) the nickel-plated metal material preferably has an iron-nickel alloy layer and/or a nickel layer between the base material and the roughened nickel layer.
In (7) described above, (8) a total deposition amount of nickel in the roughened nickel layer and the nickel layer is preferably 4.8 to 32.8 g/m².
In (7) described above, (9) a total deposition amount of nickel in the roughened nickel layer, the nickel layer, and the iron-nickel alloy layer is preferably 4.5 to 55.1 g/m².
In any one of (1) to (9) described above, (10) the roughened nickel layer is preferably formed on an outermost surface.
In any one of (1) to (9) described above, (11) preferably including, on the roughened nickel layer, a coating metal layer formed of zinc, tin, or chromium, or an alloy thereof.

[Advantageous Effect of Invention]

According to the present invention, a nickel-plated metal sheet, which includes a roughened nickel layer having shear durability even to loads from multiple directions, can be provided.

[Brief Description of Drawings]

[FIG. 1]
FIG. 1 is a cross-sectional schematic view of a nickel-plated metal material in the present embodiment.
[FIG. 2]
FIG. 2 is a cross-sectional schematic view of a nickel-plated metal material in another embodiment.
[FIG. 3]
FIG. 3 is a cross-sectional schematic view of a nickel-plated metal material in still another embodiment.
[FIG. 4]
FIG. 4 depicts schematic views of an instrument for use in shear durability tests.

[Description of Embodiments]

<<First embodiment>>

A description will hereinafter be made regarding embodiments for implementing a nickel-plated metal material of the present invention. FIG. 1 is a view schematically depicting an embodiment of a nickel-plated metal material 100 of the present invention. It is to be noted that the nickel-plated metal material 100 of the present embodiment is used for collectors of positive electrodes or negative electrodes in secondary batteries and the like, electronic related devices, and the like. Without being limited to such collectors and electronic related devices, the nickel-plated metal material 100 can be suitably used also for members required to have high adhesion with other members (active materials, resins, and the like) such as battery members, members constituting electric/electronic related devices, interior members for automobiles and constructions, automobile members such as gaskets, and sliding members.
The nickel-plated metal material 100 of the present embodiment includes a base material 20 made of metal, and a roughened nickel layer 50 formed on the base material 20.

As the metal of the base material 20 for use in the nickel-plated metal material 100 of the present embodiment, a metal sheet made of a pure metal selected from Fe, Al, or Ni or a metal sheet made of an alloy containing, as a base, one selected from Fe, Al, or Ni is preferred. Particularly preferred is a steel sheet, and as the steel sheet, a steel sheet containing iron as a base and smaller than 1.0 wt% of Cr and other additive metal elements is preferred. Specifically, low-carbon steel (carbon content: 0.01 to 0.15 wt%) represented by low-carbon aluminum-killed steel, ultralow-carbon steel having a carbon content of lower than 0.01 wt%, or non-aging ultralow-carbon steel prepared by adding Ti, Nb, and/or the like to ultralow-carbon steel is suitably used. Especially, if the nickel-plated metal material 100 is used for battery members or for electric/electronic related components, a low-carbon steel sheet or ultralow-carbon steel sheet is preferred from the viewpoint of electrical conductivity. A surface-treated steel sheet including an iron-nickel diffusion layer or an iron-nickel diffusion layer and a nickel layer on a surface thereof or a zinc-plated steel sheet can also be used, although details will be mentioned later.
As the thickness of the base material 20 for use in the nickel-plated metal material 100 of the present embodiment, a range of 0.01 to 0.5 mm is suited. If used as a current collector in a battery with a focus placed on the viewpoints of volumetric and gravimetric energy densities, the thickness of the base material 20 is more preferably 0.01 to 0.3 mm, and still more preferably 0.025 to 0.1 mm from the viewpoint of strength, the viewpoint of a desired battery capacity, and the like. For the thickness of the base material 20, a thickness measurement by a cross-sectional observation under an optical microscope or scanning electron microscope (SEM) is suitably applied. For a thickness measurement before the surface treatment, specifically before the formation of the roughened nickel layer 50, on the other hand, a thickness measurement by a micrometer, or the like can be applied.

The roughened nickel layer 50 may be formed on a surface on one side of the nickel-plated metal material 100 as depicted in FIG. 1, or may be formed on both sides although not depicted in any of the figures. The roughened nickel layer 50 is formed with nickel.
As depicted in FIG. 1, the roughened nickel layer 50 includes protruding shapes that protrude in a thickness direction of the base material 20. Describing regarding the protruding shapes, they are characterized in that a root mean square height Rq, which is a surface texture parameter of the surface of the roughened nickel layer 50 in the present embodiment, is 0.29 µm or greater and 0.90 µm or smaller. By specifying as described above, the protrusions of the roughened nickel layer 50 can bear even loads from multiple directions.
It is to be noted that surface texture parameters on the surface of the roughened nickel layer 50 can be measured by a known laser microscope or the like following Japanese Industrial Standard (JIS) B0601-2013 and International Organization for Standardization (ISO) 25178-2:2012.
The following is mentioned as a reason for enabling the roughened nickel layer 50 to bear even loads from multiple directions by specifying Rq. The roughened nickel layer 50 includes protrusions that protrude in the thickness direction of the base material 20. Focusing on the individual protrusions, the deposition and granule growth of the granular nickel plating are prioritized in a height direction, in other words, in the thickness direction of the plating metal material, than in the horizontal direction after precipitation nuclei have been formed apart from one another upon formation of protrusions with the roughened nickel plating, whereby the plurality of protrusions grow respectively. On the other hand, the heights and thicknesses of the protrusions and the sizes of clearances between the protrusions are not absolutely the same exactly.
Conventionally, Sa, Ra, and Rzjis are mentioned as surface texture parameters that have been considered to contribute to the adhesion strength with another member. Of these, parameters such as Sa and Ra are each averaged, and Sa and Ra alone do not have any close relation with the presence or absence of protrusions or with another member. On the other hand, Rzjis has been considered to have a close relation with the adhesion strength with another member. Assuming, for example, that 100 protrusions are formed side by side, those which are reflected to Rzjis are however the heights of 10 protrusions at most, and no attention has been paid concerning variations in height.
In a conventional roughened nickel-plated material, some tens of percent of its protrusions are allowed to preferentially grow over the rest of the protrusions, whereby its Rzjis is increased, and its adhesion with another member is improved. This preferential growth, however, leads to a state in which significant variations occurred when the individual protrusions are compared in height. It has been newly found that, in such a roughened nickel-plated material, preferentially grown protrusions are prone to break, because of the occurrence of variations among the heights of the individual protrusions, by loads from multiple directions during continuous rolling on the occasion of industrial manufacture of the nickel-plated metal material having a roughened nickel layer, in a step of overlaying another member on the above-described nickel-plated metal material, or in a like situation. To prevent this breakage of protrusions, it is effective to lower the height of roughening. However, the adhesion with another member becomes insufficient if Rzjis alone is merely lowered.
The present inventors have diligently studied to further improve the shear durability in nickel-plated metal materials having plating adhesion and adhesion with other members. As a result, it has been found that shear durability can be improved by reducing height differences among protrusions and optimizing the clearances between the protrusions. Further, by controlling the root mean square height Rq of the surface, on which the roughened nickel layer 50 is formed, to 0.29 µm or greater and 0.90 µm or smaller, a roughened shape can be formed in which, while the formation of protrusions of extraordinary heights is decreased, individual protrusions have a sufficient height and sufficient clearances are included, as recesses in the surface shape, between the protrusions. As a result, it has been confirmed that improvement in shear durability and adhesion with another member can be both achieved, leading to the present invention. From the viewpoint of improvement in shear durability, the upper limit of the root mean square height Rq is preferably controlled to 0.70 µm or smaller. On the other hand, the lower limit of the root mean square height Rq is preferably controlled to 0.30 µm or greater from the viewpoint that shear durability can be improved more stably, and more preferably to 0.31 µm or greater from the viewpoint that adhesion with another member can be obtained more stably.
The nickel-plated metal material in the present embodiment is also characterized in that, on a surface thereof on the side of the roughened nickel layer 50, a maximum height Sz as a surface texture parameter is greater than 3.5 µm and 10.0 µm or smaller. If Sz is excessively high, there is a possibility that protrusions of an extraordinary height may have been formed. From the viewpoint of improvement in shear durability, the maximum height Sz is therefore preferably 10.0 µm or smaller, more preferably 8.0 µm or smaller. From the viewpoint of assurance of stable adhesion with another member, Sz is preferably greater than 4.0 µm, more preferably 4.3 µm or greater. Nonetheless, the maximum height Sz is a parameter that represents the maximum value of height, that is, only one point, and Sz, if taken alone, has neither correlation to the adhesion with another member nor correlation to shear durability.
In the present embodiment, for the achievement of improvement in shear durability to loads from multiple directions or both shear durability and adhesion with another member, it is preferred to further specify the following surface texture parameters.
In the nickel-plated metal material of the present embodiment, Sdr (Developed Interfacial Area Ratio) is preferably 16% to 75% on the surface thereof on the side of the roughened nickel layer 50. By controlling Sdr (Developed Interfacial Area Ratio), that is, an area increment to the area of a defined region, which is attributable to the formation of the roughened nickel layer, to 16% or greater, the adhesion with another member can be improved further, and by controlling Sdr (Developed Interfacial Area Ratio) to 75% or smaller, the preferential growth of protrusions, when the roughened shape of the nickel-plated metal material is perceived as a surface, can be suppressed, and the shear durability can be improved. From the viewpoint of improvement in adhesion with another member, Sdr is preferably 17% or greater, more preferably 18% or greater, particularly preferably 20% or greater. From the viewpoint of improvement in shear durability, on the other hand, Sdr is more preferably 70% or smaller, and still more preferably 65% or smaller.
In the nickel-plated metal material of the present embodiment, a relative load length ratio Rmr is preferably 30% to 95% on the surface on the side of the roughened nickel layer 50. When a roughened layer is considered by separating it into a root region, a core region, and a tip region in a height direction, the control of the relative load length ratio Rmr to 30% or greater can stabilize the roughened shape of the core region, and can improve its shear durability. By increasing the number of protrusions that fill the core regions and forming protrusions that are not excessively steep, Rmr is controlled to 33% or greater. As a result, it is possible not only to suppress some protrusions from preferentially growing but also to form a roughened shape that more protrusions are difficult to break even when loads in multiple directions are applied. It is hence inferred that the shear durability can be improved. Especially in the present embodiment, the control of Sdr (Developed Interfacial Area Ratio) to 16% or greater can improve the adhesion with another member even when the shear durability is improved by increasing Rmr. From the viewpoint that the shear durability can be improved more stably, Rmr is more preferably 33% or greater, still more preferably 50% or greater, and particularly preferably 65% or greater. No upper limit is imposed in particular, but 95% or smaller is preferred because there is a concern that the clearances, into which another member are supposed to penetrate, could be narrowed if Rmr is excessively great.
In the nickel-plated metal material of the present embodiment, a root mean square slope RΔq is preferably 15 to 50 degrees on the surface on the side of the roughened nickel layer 50. By controlling, as the roughened shape derived from the protrusions, Rq, to which the variations in height among the protrusions are reflected, to 0.29 µm or greater and 0.90 µm or smaller, and RΔq, to which slopes of the individual protrusions are strongly reflected, to 15 to 50 degrees when measured in a direction perpendicular to a rolling direction, it is possible to form a roughened shape that is difficult to break and has clearances easy for another member to enter but difficult to slip out. As a result, it is possible to obtain more preferred improvement in shear durability and improvement in the adhesion with another member. From the viewpoint of improvement in the adhesion with another member, the lower limit of the root mean square slope RΔq is more preferably 20 degrees or greater, and still more preferably 25 degrees or greater.
In the nickel-plated metal material of the present embodiment, Sdq (Root Mean Square Gradient) on the surface on the side of the roughened nickel layer 50 is preferably 0.50% or greater from the viewpoint of improvement in the adhesion with another member, and is preferably 1.80% or smaller from the viewpoint of improvement in shear durability. Sdq (Root Mean Square Gradient) is a value when the slopes of surface recesses and protrusions of the nickel-plated metal material are perceived over the entirety of the surface. It can be said that the protrusions and recesses on the surface are gentler as the value is smaller and are steeper as the value is greater. If Sdq falls in the above-described range, improvement in shear durability is considered to be possible because the recesses and protrusions when perceived over the surface are relatively gentle despite the protrusions having heights. Especially in the present embodiment, a shape formed by aggregation of plating granules on the tip of each protrusion is adequately rounded, and as a result, it is considered possible to control Sdq to 1.80% or smaller and to improve the shear durability. It is to be noted that Sdq is preferably 0.50% or greater, more preferably 0.65% or greater, because the adhesion with another member may become insufficient if Sdq is excessively small. As appreciated from the foregoing, in the nickel-plated metal material of the present embodiment, Sdq (Root Mean Square Gradient) is preferably 0.50% to 1.80% on the surface on the side of the roughened nickel layer 50 from the viewpoints of improvement in shear durability and the adhesion with another member.
On the surface on the side of the roughened nickel layer 50, a ten-point mean roughness Rzjis is preferably 1.0 to 6.0 µm. More preferably, the ten-point mean roughness Rzjis is 1.5 to 4.9 µm, with 1.5 to µm being still more preferred.
Further, the arithmetical mean roughness Sa is preferably 0.2 to 0.7 µm on the surface on the side of the roughened nickel layer 50.
In the nickel-plated metal material 100 of the present embodiment, the deposition amount of nickel in the roughened nickel layer 50 is preferably 3.5 to 19.0 g/m² from the viewpoints of improvement in shear durability and assurance of adhesion with another member. More preferred is 4.5 to 14.5 g/m², and still more preferred is 5.5 to 13.9 g/m².
As a measuring method of the nickel deposition amount in the roughened nickel layer 50 in the present embodiment, the method described in PCT Patent Publication No. WO2020/017655 or PCT Patent Publication No. WO2021/020338 , or the like can be appropriately adopted, for example. Specifically, the nickel deposition amount can be determined by measuring the total nickel amount with respect to the nickel-plated metal material 100 using X-ray fluorescence (XRF) analysis or the like.
A description will be made regarding the thickness of the entirety of the nickel-plated metal material 100 in the present embodiment. Here, to the "thickness of the nickel-plated metal material 100" in the present embodiment, a thickness measurement by a cross-sectional observation under an SEM or a thickness measurement by a micrometer can be also applied.
As the thickness of the entirety of the nickel-plated metal material 100 in the present embodiment, a range of 0.02 to 0.51 mm is preferred. Further, the thickness of the entirety of the nickel-plated metal material 100 is more preferably 0.02 to 0.31 mm, and still more preferably 0.035 to 0.11 mm, for example, from the viewpoint of strength, the viewpoint of a desired battery capacity, and the like.
As described above, the nickel-plated metal material 100 in the present embodiment can be provided as a nickel-plated metal material that includes a roughened nickel layer having shear durability to loads from multiple directions.

<<Second embodiment>>

On the basis of FIG. 2, a description will be made regarding a nickel-plated metal material 200 as a second embodiment. The nickel-plated metal material 200 in the present embodiment is different from the above-mentioned first embodiment in that, as depicted in FIG. 2, an intermediate metal layer 40 formed between the base material 20 and the roughened nickel layer 50 is included. Accordingly, this different point will be primarily described, the other points will be identified by the same reference signs, and their description is omitted. It is to be noted that, in this second embodiment, the root mean square height Rq and maximum height Sz on the surface on the side of the roughened nickel layer are also 0.29 µm or greater and 0.90 µm or smaller, and greater than 3.5 µm and 10.0 µm or smaller, respectively. It is to be noted that the nickel-plated metal material 200 of the present embodiment is also used for collectors of positive electrodes or negative electrodes in secondary batteries and the like, electronic related devices, and the like. Without being limited to such collectors and electronic related devices, the nickel-plated metal material 200 can be suitably used also for members required to have high adhesion with other members (active materials, resins, and the like) such as battery members, members constituting electric/electronic related devices, interior members for automobiles and constructions, automobile members such as gaskets, and sliding members.

As the intermediate metal layer 40 included in the nickel-plated metal material 200 of the present embodiment, a nickel layer, a nickel alloy layer, a layer with nickel and another metal stacked together, or the like is exemplified. In the case of the nickel alloy layer, an iron-nickel alloy layer is exemplified. In the case of the layer with nickel and another metal stacked together, a layer with a nickel layer and an iron-nickel alloy layer stacked together can be exemplified.
The formation of a nickel layer as the intermediate metal layer 40 is effective in that the adhesion of the roughened nickel layer 50 with the base material 20 is improved and shear durability can be obtained more stably.
If the intermediate metal layer 40 is formed from a nickel layer alone, the total of the nickel deposition amount in the nickel layer is preferably 1.3 to 13.8 g/m² from the viewpoints of the adhesion with the base material and improvement in shear durability to loads from multiple directions. More preferred is 1.5 to 12 g/m². Still more preferred is 1.7 to 8.8 g/m² from the viewpoint of shear durability. The deposition amount of nickel in the nickel layer can be measured by X-ray fluorescence (XRF) analysis or the like.
The total deposition amount of nickel per side of the nickel-plated metal material in the case that the intermediate metal layer 40 is formed from the nickel layer alone is preferably 4.8 to 32.8 g/m², more preferably 6.0 to 26.5 g/m², and still more preferably 7.2 to 23.3 g/m² from the viewpoints of the adhesion with another member and improvement in shear durability. The above-described total deposition amount is the total of deposition amounts of nickel contained in the nickel layer and the roughened nickel layer, respectively.
Further, concerning the thickness of the nickel layer, the thickness is preferably 0.1 to 1.0 µm, more preferably 0.1 to 0.8 µm, from the viewpoints of making small the thickness of the entirety of the nickel-plated metal material 200 while ensuring shear durability or the like to loads from multiple directions. Furthermore, from the view point of shear durability, 0.12 µm or greater is preferred, with 0.15 µm or greater being particularly preferred.
As a measuring method of the thickness of the nickel layer, a thickness measurement based on an analysis by SEM-energy dispersive X-ray spectroscopy (EDX) can be applied.
If the intermediate metal layer 40 is a stacked layer of a nickel layer and an iron-nickel layer, no particular limitation is imposed on the order of their stacking. For example, the iron-nickel alloy layer, the nickel layer, and the roughened nickel layer 50 may be stacked in this order from the base material 20. Further, a metal layer of a kind different from nickel and iron may be formed between the base material 20 and the roughened nickel layer 50. From the viewpoint of improvement in the plating adhesion of the roughened nickel layer 50 with the base material, it is preferred to stack in the order of the iron-nickel alloy layer, the nickel layer, and the roughened nickel layer 50.
The iron-nickel alloy layer is an alloy layer with iron (Fe) and nickel (Ni) contained therein, and is a metal layer in which an alloy formed of iron and nickel (also called an "iron-nickel alloy" or an "Fe-Ni alloy") is contained. It is to be noted that, as the phase of this alloy formed of iron and nickel, it may be any one of a solid solution, an eutectoid/eutectic, and a compound (intermetallic compound), or two or more of these phases may coexist.
The iron-nickel alloy layer may contain one or more other metal elements and inevitable impurities insofar as the problem intended to be solved in the present invention can be solved. For example, metal elements such as cobalt (Co) and molybdenum (Mo) and an additive element such as boron (B) may be contained in the iron-nickel alloy layer. It is to be noted that the proportion of metal elements other than iron (Fe) and nickel (Ni) in the iron-nickel alloy layer is preferably 5 wt% or lower, more preferably 3 wt% or lower, and still more preferably 1 wt% or lower. As the iron-nickel alloy layer may be a binary alloy formed substantially from only iron and nickel, the lower limit of the content proportion of one or more other metal element or elements except for inevitable impurities is 0%.
The kinds and amounts of one or more other metal elements contained can be determined by known means such as X-ray fluorescence (XRF) spectrometer or glow discharge optical emission spectroscopy (GDS).
As the thickness of the iron-nickel alloy layer included in the nickel-plated metal material 200 of the present embodiment, 0.4 µm or greater is preferred, 0.6 µm or greater is preferred, and 0.7 µm or greater is more preferred. No upper limit is imposed in particular, but as the resistance increases if excessively thick, the thickness is preferably 7.5 µm or smaller, more preferably 6 µm or smaller, per side. Especially, if a continuous steel strip is used as the base material 20, specifically if the nickel-plated metal material of the present embodiment, which has the iron-nickel alloy layer, is obtained by applying surface treatment to a continuous steel strip, the thickness is preferably 6 µm or smaller, more preferably 3.5 µm or smaller from the viewpoint of avoidance of unevenness in metal deposition amount control and heat treatment. As a measuring method of the thickness of the iron-nickel alloy layer, a thickness measurement based on an analysis by SEM-EDX on a cross-section of the nickel-plated metal material can be applied. Specifically, a method that reads a thickness from a graph obtained by SEM-EDX can be applied as in PCT Patent Publication No. WO2022/231009 .
If the iron-nickel alloy layer is included, the deposition amount of nickel in the iron-nickel alloy layer is preferably 0.89 to 26.7 g/m². 1.3 to 17.8 g/m² is more preferred. It is to be noted that the deposition amount of nickel in the iron-nickel alloy layer can be measured by X-ray fluorescence (XRF) analysis or the like.
If both the iron-nickel layer and the nickel layer are included as the intermediate metal layer 40, the total of the deposition amount of nickel in the iron-nickel alloy layer and the deposition amount of nickel in the nickel layer, in other words, the total deposition amount of nickel contained in the intermediate metal layer 40, is preferably 1.0 to 36.1 g/m² from the viewpoint of stable deposition of the roughened plating. In this range, the nickel deposition amount in the nickel layer is preferably 0.08 to 8.8 g/m², more preferably 0.13 to 7.6 g/m², and still more preferably 1.1 to 7.1 g/m² from the viewpoint of stable deposition of the roughened plating.
It is to be noted that the nickel-plated metal material 200 can be obtained by steps including, for example, nickel plating treatment, heat treatment for obtaining the iron-nickel alloy layer, strike nickel-plating treatment, undercoat nickel-plating treatment, and roughened nickel-plating treatment. The deposition amount of nickel in the nickel layer at this time can be controlled on the basis of the deposition amounts upon the strike nickel-plating treatment and the undercoat nickel-plating treatment. Further, the nickel layer may be formed without allowing iron to diffuse to the surface in the above-described heat treatment step, and the strike nickel treatment and the undercoat nickel-plating treatment may be further applied to the nickel layer. It is to be noted that the deposition amount of nickel in the nickel layer of the nickel-plated metal material 200 in the foregoing case is preferably determined through conversion to the deposition amount from the thickness by a cross-sectional observation.
The total deposition amount of nickel per side of the nickel-plated metal material in the case that the iron-nickel alloy layer is included is preferably 4.5 to 55.1 g/m², more preferably 5.9 to 39.9 g/m², and still more preferably 8.1 to 36.5 g/m² from the viewpoints of adhesion with another member, improvement in shear durability, and improvement in corrosion resistance. The above-described total deposition amount is the total of deposition amounts of nickel contained in the iron-nickel alloy layer, the nickel layer, and the roughened nickel layer, respectively.
As a measuring method of the nickel deposition amount in the present embodiment, the method described in PCT Patent Publication No. WO2020/017655 or PCT Patent Publication No. WO2021/020338 , or the like can be appropriately adopted, for example. Specifically, the nickel deposition amount can be determined by measuring the total nickel amount with respect to the nickel-plated metal material 200 using X-ray fluorescence (XRF) analysis or the like.
It is to be noted that the intermediate metal layer 40 is formed on one side of the base material 20 in FIG. 2, but without being limited to this configuration, such intermediate metal layers may be formed on both sides, respectively, of the base material 20 although not depicted in any of the figures. Further, in the case that the intermediate metal layers 40 are formed on both sides, the thickness of one of the intermediate metal layers 40 may be the same as or different from that of the other intermediate metal layer 40.
As a forming method of the intermediate metal layer 40, a method by plating or plating and heat treatment is preferred. Examples of the plating include methods such as electrolytic plating, electroless plating, melt plating, dry plating, and the like. Of these, the method by electrolytic plating is particularly preferred from the viewpoints of cost, film thickness control, and the like.
Examples of a manufacturing method in the case that the intermediate metal layer 40 is an iron-nickel alloy layer include a method that forms the nickel plating layer on at least one side of the base material 20 by a method such as electrolytic plating, and iron (Fe) in the base material 20 and nickel (Ni) in the nickel plating layer are then caused to diffuse into an alloy by thermal diffusion treatment or the like, and a method that forms an alloy layer by iron-nickel alloy plating. If a nickel layer is formed on the iron-nickel alloy layer, the nickel layer is obtained by a method that forms the nickel layer by leaving a region of nickel alone without allowing iron (Fe) to diffuse to the surface in the above-described thermal fusion treatment, a method that applies nickel plating after the above-described thermal fusion treatment to form the nickel layer, a method that forms the nickel layer by a combination of both of these methods, or a like method, or a roughened nickel layer may be formed after subjecting the surface-treated steel sheet, which has been provided with the iron-nickel alloy layer by the above-described thermal fusion treatment, to rolling or rolling and heat treatment. It is to be noted that details regarding these manufacturing methods will be mentioned later.

<<Third embodiment>>

On the basis of FIG. 3, a description will next be made regarding a nickel-plated metal material 300 in a third embodiment. The nickel-plated metal material 300 in the third embodiment is different from the above-mentioned first embodiment in that, as depicted in FIG. 3, a coating metal layer 70 is included on the roughened nickel layer 50. Accordingly, this different point will be primarily described, the other points will be identified by the same reference signs, and their description is omitted. It is to be noted that, in this third embodiment, the roughened nickel layer 50 and the coating metal layer 70 may also be collectively called a "roughened layer." In this third embodiment, individual surface texture parameters as measured from the side of the roughened layer should fall within the specified ranges in the first embodiment. It is to be noted that the nickel-plated metal material 300 of the present embodiment is also used for collectors of positive electrodes or negative electrodes in secondary batteries and the like, electronic related devices, and so on. Without being limited to such collectors and electronic related devices, the nickel-plated metal material 300 can be suitably used also for members required to have high adhesion with other members (active materials, resins, and the like) such as battery members, members constituting electric/electronic related devices, interior members for automobiles and constructions, automobile members such as gaskets, and sliding members.

As mentioned above, the coating metal layer 70 is formed on the roughened nickel layer 50. Example of a metal material forming the coating metal layer 70 include zinc (Zn), tin (Sn), and chromium (Cr), and alloys thereof. The inclusion of the coating metal layer 70 is advantageous in that, as a whole, the nickel-plated metal material 300 is provided with improvement in sacrificial corrosion protection property or corrosion resistance. In addition, the coating metal layer 70 also contributes to improvement in adhesion between the roughened nickel layer 50 and the base material 20.
If the coating metal layer 70 is zinc, the zinc deposition amount is preferably 0.5 to 22.0 g/m². If the coating metal layer 70 is chromium, the chromium deposition amount is preferably 0.05 to 10.0 g/m². If the coating metal layer 70 is tin, the tin deposition amount is preferably 0.2 to 20.0 g/m². Measurements of respective deposition amounts of zinc, chromium, and tin can be conducted by using a known method such as X-ray fluorescence (XRF) analysis or inductively coupled plasma (ICP) emission spectroscopy.
The coating metal layer 70 in the present embodiment can be formed by applying electroplating with the corresponding metal on the roughened nickel layer 50. It is to be noted that, in the third embodiment, the intermediate metal layer 40 in the second embodiment may more preferably be included between the roughened nickel layer 50 and the base material 20.

<<Manufacturing methods of nickel-plated metal materials>>

A description will hereinafter be made regarding manufacturing methods of the nickel-plated metal materials in the above-mentioned embodiments. The manufacturing method of each nickel-plated metal material includes a step (roughened nickel-plating step) that applies roughened nickel-plating to at least one side of the base material 20 to form the roughened nickel layer. The roughened nickel-plating step includes at least a first roughened nickel-plating step, and, after the first roughened nickel-plating step, may also include a second roughened nickel-plating step for improvement in the adhesion of the roughened nickel layer with the base material.
As a plating bath in the first roughened nickel-plating step for the formation of the roughened nickel layer 50, nickel sulfate hexahydrate or/and nickel chloride hexahydrate are used such that their total amount is 10 g/L (inclusive) to less than 48 g/L, the chloride ion concentration is preferably 5 to 90 g/L, more preferably 5 to 75 g/L, and still more preferably 10 to 50 g/L, the ratio of nickel ions to ammonium ions is preferably 0.05 to 0.75, more preferably 0.05 to 0.60, still more preferably 0.05 to 0.50, and even still more preferably 0.05 to 0.30, in terms of the weight ratio of "nickel ions/ammonium ions," and the bath electrical conductivity at 50°C is preferably 5.00 to 30.00 S/m, more preferably 5.00 to 20.00 S/m, and still more preferably 7.00 to 20.00 S/m.
It is to be noted that, if the chloride ion concentration is 10 g/L or higher, a good roughened plating state is easily obtained even if the deposition amount in roughened nickel-plating is somewhat small. Examples of a method that adjusts the chloride ion concentration of the plating bath, the ratio of nickel ions to ammonium ions, and the bath electrical conductivity to the above-described ranges include, but are not particularly limited to, a method that uses, as the plating bath, one containing nickel sulfate hexahydrate, nickel chloride hexahydrate, and ammonium sulfate, and appropriately adjusts their blending amounts. The addition of ammonia to the nickel-plating bath may be conducted by using ammonia solution, ammonium chloride, or the like in place of ammonium sulfate. The ammonia concentration in the plating bath is preferably 6 to 35 g/L, more preferably 10 to 35 g/L, still more preferably 16 to 35 g/L, and even still more preferably 20 to 35 g/L. Further, a basic nickel carbonate compound, hydrochloric acid, sodium chloride, potassium chloride, or the like may be used to control the chlorine ion concentration.
The present inventors have found that a nickel-plated metal material, which is excellent in shear durability and has adhesion with another member, is obtained by using, as a circulating bath, a plating bath of a formula, in which the chloride ion concentration, the ratio of nickel ions to ammonium ions, and the ammonia concentration have been controlled to the above-described ranges, and intermittently conducting plating treatment a plurality of times at a current density of 15.0 A/dm² or higher in the first roughened nickel-plating step.
In the present embodiment, the expression "using as a circulating bath" means that electroplating is conducted while maintaining solution circulation by a pump through a plating solution in a plating tank. It is preferred for the solution circulation to control the pump-assisted circulation rate of the solution at a flow rate of 25 L/min or higher per 1000 L of the plating filled in the plating solution tank. Especially, if a tank of over 1000 L is used, the solution circulation is preferably a circulation that flows in from a lower part of the tank and flows out of the tank from an upper part of the tank. Here, it is more preferred to adjust, within ±25%, the respective concentrations of nickel ion concentration, ammonium ion concentration, and chloride ion concentration in the plating solution, the nickel ions, ammonium ions, and chloride ions to be consumed during the plating, while maintaining the liquid circulation.
The expression "intermittently conducting plating treatment a plurality of times" means to define, as one cycle, three steps, that is, a step of inserting a base material or a pretreated base material into a plating bath, an energizing and electrolytically precipitating step, and a step of pulling up from the plating bath, and to repeat this cycle at least twice or more.
The conventional roughened nickel-plating step has used, for example, a drum-type plating bath, or a single plating bath in a laboratory, and has conducted the above-described cycle in one cycle. When formed by such a manufacturing method, the formation of preferentially growing protrusions is facilitated among protrusions that make up a roughened shape, thereby facilitating improvement of the adhesion with another member such as resin or the like. If attempted to suppress the overall height in the conventional manufacturing method, on the other hand, the protrusions other than the preferentially growing protrusions are excessively short, and the resin adhesion is significantly lowered. It has been therefore difficult to improve the shear durability.
With the foregoing in view, the present inventors have conducted diligent deliberation for a roughened shape, which can suppress preferential growth of protrusions and can obtain adhesion with another member, in order to obtain shear durability to loads in multiple directions upon continuous rolling or the like, and its manufacturing method, and have found that a roughened shape having shear durability can be obtained by combining control of the current density to 15.0 A/dm² or higher, circulation of a plating solution, and a plurality of times of plating treatment. Giving as a reason that a good roughened shape is obtained by such a combination, the following consideration can be made.
First, by circulating a plating solution and repeating insertion into and pull-up from the plating solution, the plating solution is constantly supplied with sufficient ion concentrations and without stagnation to a surface of a target (base material) that is under roughened nickel-plating treatment. Therefore, the ion concentrations in the plating solution in a neighborhood of the base material can be made even, thereby creating a state that irregularity is hard to occur on precipitation starting points, and hence making it possible to obtain still more precipitation points. Further, the adoption of a plurality of timings to dip into the plating solution can suppress some protrusions from preferentially growing, thereby allowing many protrusions to grow uniform. Therefore, if electroplating is continued by one dipping operation, the ion concentrations decrease around protrusions that have begun to preferentially grow, their surrounding protrusions are rendered hard to grow, and the protrusions that have begun to preferentially grow are hence facilitated to grow more preferentially. In contrast, even if there are protrusions that have begun to preferentially grow, an environment in which the iron concentrations needed for the growth of their surrounding protrusions are sufficient can be created by conducting the plating treatment a plurality of times, and, as a result, an environment easy for still more protrusions to grow is created. Therefore, differences in height among the protrusions themselves can be suppressed, and the thickness, number, and density of the protrusions can be made appropriate.
Moreover, by controlling the total amount of nickel sulfate hexahydrate and/or nickel chloride hexahydrate to 10 g/L (inclusive) to less than 48 g/L in the plating bath, the chloride ion concentration and the ratio of nickel ions to ammonium ions to the above-described ranges, and the current density to 15.0 A/dm² or higher, precipitation in the height direction for the formation of protrusions and granule growth for the thickening of the protrusions can be promoted while suppressing such precipitation and growth that precipitated nickel-plating granules excessively grow in a horizontal direction into a layer. In the conventional manufacturing method, if the current density is increased, preferentially grown protrusions further grow preferentially and become excessively tall, and, as a result, shear durability becomes hard to obtain. In the present application, however, it is effective for the uniform precipitation of protrusions in the height direction to increase the current density in addition to the circulation of the plating solution and the plurality of times of the plating treatment. The current density is preferably 15.0 A/m² or higher, more preferably 18.0 A/m² or higher.
If the current density is excessively high, however, there is a possibility that the supply of ions may not be in time for precipitation and a roughened shape may hence not be obtained. Accordingly, the current density is preferably 40 A/dm² or lower, more preferably 35 A/dm² or lower. Here, when conducting the plating treatment a plurality of times, it is more preferred that the current density during energization in each cycle is 15 to 40 A/dm², and the average current density in all the cycles is 15 to 40 A/dm². Still more preferably, the current density during energization in each cycle is 18 to 35 A/dm², and the average current density in all the cycles is 18 to 35 A/dm². It is preferred to conduct the plating treatment with an electricity quantity of 100 to 1500 C/dm² in such a current density range.
It is to be noted that precipitation points increase in number or granule growth is prone to occur excessively if the total amount of nickel sulfate hexahydrate and nickel chlorate hexahydrate in the plating bath is 48 g/L or more. Even if a granular precipitate is formed and the surface is coarse compared with a general nickel plating, the intended roughened shape is thus difficult to be obtained in a case where, for example, tall protrusions are not formed, clearances are too small to obtain adhesion with another member, or aggregates cannot grow into the shape of a protrusion due to too many precipitation points. In a case of less than 10 g/L, on the other hand, nickel ions for the precipitation of nickel run out, and hence, there is a possibility that nickel may not precipitate and a roughened nickel layer may not be obtained.
As described above, by using a plating bath of the above-described formula as a circulating bath and conducting plating treatment a plurality of times at a current density of 15.0 A/dm² or higher in the first roughened nickel-plating step, a roughened nickel layer excellent in shear durability and also excellent in adhesion with another member can be obtained.
Examples of plating conditions are as follows.

[First roughened nickel-plating conditions]

Bath composition:

Nickel sulfate hexahydrate: 10 to 45 g/L, nickel chloride hexahydrate: 1 to 40 g/L, ammonium sulfate: 10 to 130 g/L
pH: to 8.0
Bath temperature: 25°C to 70°C
Average current density: 15 to 40 A/dm²
Plating time: 5 to 100 seconds
Electricity quantity: 100 to 1500 C/dm²
Agitated/not agitated etc.: circulating bath

Under the above-described conditions, a plurality of plating treatment can be conducted in the circulating bath by adjusting the average current density and electrolysis time such that the total electricity quantity is controlled as described above. The plating time is preferably 7 to 60 seconds, because if the plating time is short, some protrusions are prone to preferentially grow, and if too long, protrusions grow uniform and tall protrusions are prone to grow.
The roughened nickel layer may be obtained by only the above-described first roughened nickel-plating step, or the roughened nickel layer may be obtained by conducting the second roughened nickel-plating step under the below-described conditions after the first roughened nickel-plating step.

Bath composition:

Nickel sulfate hexahydrate 200 to 350 g/L, nickel chloride hexahydrate 20 to 60 g/L, boric acid 10 to 50 g/L
pH: 3.0 to 5.0
Bath temperature: 40°C to 70°C
Current density: 5 to 30 A/dm²

Effects by the second roughened nickel-plating are as follows. Firstly, by promoting the growth of the individual plating granules in the aggregates of the protruding granular precipitate formed by the first roughened nickel-plating, minute clearances between the granules themselves inside the aggregates are filled up with a highly compatible crystalline structure, whereby the protrusions can be made more difficult to break. Secondly, on the roots of protrusions, nickel crystals precipitate, similarly filling up clearances between the base material and the particles of the roots of the protrusions, or covering both, whereby the adhesion between the base material and the protrusions is improved to make the protrusions more difficult to break. Thirdly, by promoting the growth of the above-described each plating granule, the side wall of the protrusion also undergoes granule growth, and the protrusion can be made thicker and more difficult to break. Fourthly, by allowing the granules on the tips of protrusions to grow, better adhesion with another member can be obtained, and the tip particles are made hard to fall off when they come into contact with rolls or the like, whereby the shear durability can be also improved.
Here, if the roughened shape obtained in the first roughened nickel-plating step is provided with sufficient shear durability and sufficient adhesion with another member, it is not absolutely necessary to go through the second roughened nickel-plating step, but in the first embodiment and the second embodiment, it is preferred to conduct the second roughened nickel-plating step. Further, in a case where the coating metal layer 70 is formed with metal other than nickel on the roughened nickel layer in the third embodiment, a step of forming the coating metal layer 70 may be conducted after the second roughened nickel-plating step, or the step of forming the coating metal layer 70 may be conducted instead of the second roughened nickel-plating step.
If the nickel-plated metal material is formed from the base material and the roughened nickel layer (see FIG. 1), the deposition amount of the roughened nickel layer is preferably 3.5 to 19.0 g/m², more preferably 4.5 to 14.5 g/m², and still more preferably 5.5 to 13.9 g/m².
If the roughened nickel layer is formed by the first roughened nickel-plating step and the second roughened nickel-plating step, the nickel deposition amount in the first roughened nickel-plating (hereinafter also called the "first deposition amount") is preferably controlled to 3.5 to 12.0 g/m² from the viewpoints of assurance of adhesion with another member and improvement in shear durability. From the viewpoint of the improvement in the adhesion with another member, the first deposition amount is controlled more preferably to g/m² or more. In addition, from the viewpoints of suppressing the preferential growth of some protrusions and improving the shear durability, the first deposition amount is controlled more preferably to 9.3 g/m² or less, and still more preferably to 8.9 g/m² or less.
As the second roughened nickel-plating step may be skipped if sufficient effects are obtained from the first roughened nickel-plating step, the lower limit of the nickel deposition amount in the second roughened nickel-plating step (hereinafter also called the "second deposition amount") is 0.0 g/m². From the viewpoints of assurance of stable plating adhesion and improvement of shear durability, the second adhesion amount is preferably 1.0 g/m² or more, more preferably 1.5 g/m² or more. From the viewpoint of improvement in the adhesion with another member, the second adhesion amount is preferably 7.0 g/m² or less, more preferably 5.2 g/m² or less, and still more preferably 5.0 g/m² or less.
If the intermediate metal layer is a nickel layer in the manufacturing method of the nickel-plated metal material depicted in FIG. 2, a step of forming a nickel layer by applying nickel plating onto the base material 20 (hereinafter also referred to as the "nickel-plating step" or the "undercoat nickel-plating step") may be included. Examples of nickel-plating conditions for the nickel-plating step will hereinafter be described.

[Examples of nickel-plating bath (Watts bath) and plating conditions]

Bath composition:
- Nickel sulfate hexahydrate: 200 to 300 g/L Nickel chloride hexahydrate: 20 to 60 g/L
- Boric acid: 10 to 50 g/L
- Bath temperature: 40°C to 70°C
- pH: 3.0 to 5.0
- Agitation: air agitation or jet agitation
- Current density: 5 to 30 A/dm²

It is to be noted that, as to the bath composition, a known nickel sulfamate bath or citrate bath may also be used beside the above-described Watts bath. In addition, an additive such as a known gloss agent may be added to the plating bath to form gloss nickel-plating or semi-gloss nickel-plating.
Especially, if the base material is a metal sheet made of Al or an Al-based alloy, it is preferred to go through the nickel-plating step. At this time, it is preferred to carry out degreasing treatment, pickling treatment, desmut treatment, and zincate treatment before the nickel-plating step.
It is to be noted that, with a view to removing oxides and a passive film, strike nickel-plating treatment may be applied under the below-described conditions before the roughened nickel-plating step or undercoat nickel-plating step.

Bath composition:

Nickel sulfate hexahydrate 100 to 300 g/L, sulfuric acid: 10 to 20 g/L
pH: 1.0 or lower
Bath temperature: 40°C to 70°C
Current density: 5 to 100 A/dm²
Plating time: 3 to 100 seconds
Deposition amount: 0.01 to 0.3 g/m²

Especially, if the base material is a metal sheet made of an alloy based on one type selected from a pure metal selected from Ni, Fe other than a carbon steel sheet, and Ni, or if an iron-nickel alloy layer is formed, it is preferred to go through a step of strike nickel-plating treatment.
If the intermediate metal layer is the iron-nickel alloy layer in the manufacturing method of the nickel-plated metal material depicted in FIG. 2, an iron-nickel alloy layer forming step may be included to form the iron-nickel alloy layer on the base material 20. In addition, the above-mentioned roughened nickel-plating step may be conducted after the above-mentioned iron-nickel alloy layer forming step.
The iron-nickel alloy layer forming step can form the iron-nickel alloy layer through thermal diffusion by applying thermal diffusion after forming the nickel-plating layer on at least one side of a steel sheet as the base material 20 by electrolytic plating. It is to be noted that, in this case, the above-mentioned nickel-plating conditions can be applied as the step which forms the nickel-plating layer. As the heat treatment after the formation of the nickel-plating layer, continuous annealing or batch annealing (box annealing) can be conducted. As examples of a temperature and time in a case of continuous annealing treatment, the continuous annealing treatment can be conducted at 650°C to 950°C for a soaking time in a range of 15 to 150 seconds. As examples of a temperature and time in a case of batch annealing (box annealing) treatment, the batch annealing (box annealing) treatment can be conducted at 450°C to 690°C, for a soaking time in a range of 1.5 to 20 hours, and for a total time of heatup, soaking, and cooling time in a range of 4 to 80 hours. Rolling may be applied after the above-described heat treatment. Further, heat treatment may be conducted again after the rolling.
As an alternative, the iron-nickel alloy layer as the intermediate metal layer may also be formed by applying alloy electrolytic plating to at least one side of the base material 20 using an iron-nickel alloy plating bath containing iron ions and nickel ions. Examples of plating conditions will hereinafter be described.

[Examples of iron-nickel alloy plating bath and plating conditions]

Bath composition:
- Nickel sulfate hexahydrate: 150 to 250 g/L
- Iron sulfate heptahydrate: 5 to 100 g/L
- Nickel chloride hexahydrate: 20 to 50 g/L
- Boric acid: 20 to 50 g/L
- Sodium citrate (or trisodium citrate): 1 to 15 g/L
- Saccharin sodium: 1 to 10 g/L
Temperature: 25°C to 70°C
pH: 2 to 4
Agitation: air agitation or jet agitation
Current density: 5 to 40 A/dm²

In the manufacturing method of the present embodiment, the deposition amount of nickel in the intermediate metal layer to be formed on the base material 20 is preferably 1.3 to 36.1 g/m² per side. If the deposition amount exceeds 36.1 g/m², the operability of electrolytic plating is lowered, so that the cost increases significantly. If the deposition amount is less than 1.3 g/m², there is a possibility that irregular shapes are prone to occur in the subsequent roughened nickel-plating step, and such a deposition amount is not preferred accordingly.
It is to be noted that, owing to the above-described roughened nickel-plating conditions, the present embodiment can suppress the formation of protrusions having a prominent height. As a result, not only shear durability but also plating adhesion can be heightened, whereby the deposition amount of nickel in the intermediate metal layer can be reduced.
If the intermediate layer is formed of a nickel layer alone, the deposition amount of nickel in the nickel layer to be formed by nickel plating or strike nickel-plating is preferably 1.3 to 13.8 g/m², more preferably 1.5 to 12 g/m², and still more preferably 1.7 to 8.8 g/m² per side from the viewpoint of improvement in shear durability.
If an iron-nickel alloy layer is included in the intermediate metal layer, the nickel deposition amount of the nickel layer to be formed by nickel plating and strike nickel-plating after the formation of the iron-nickel alloy layer is preferably 0.08 to 8.8 g/m², more preferably 0.13 to 7.6 g/m², and still more preferably 1.1 to 7.1 g/m² from the viewpoints of improvement in shear durability and improvement in corrosion resistance.
It is to be noted that, if a stacked layer of a nickel layer and an iron-nickel alloy layer is formed as the intermediate metal layer, the above-mentioned step of forming the nickel layer and the above-mentioned step of forming the iron-nickel alloy layer may be both included. In this case, the nickel layer can be formed in a known nickel bath such as the above-mentioned Watts bath, nickel sulfamate bath, or citrate bath. Further, the above-described manufacturing method of the nickel-plated metal material may include, shortly before forming the nickel layer, a step of applying known strike nickel-plating treatment. Furthermore, the nickel layer and the iron-nickel alloy layer may be stacked together by allowing a nickel portion to remain when conducting diffusion by heat treatment in the step of forming the iron-nickel alloy layer.
The manufacturing method of the nickel-plated metal material depicted in FIG. 3 may include a step (coating metal plating step) of forming a coating metal layer by applying coating metal plating onto the roughened nickel layer formed by the above-mentioned roughened nickel-plating step.
If electro-zinc plating is used as the coating metal plating, examples of bath composition for the electro-zinc plating and plating conditions are as follows.

Zinc sulfate heptahydrate: 100 to 400 g/L
Sodium sulfate: 10 to 100 g/L
Bath temperature: 30°C to 70°C
pH: 0.5 to 5.0
Agitation: air agitation or jet agitation
Current density: 10 to 60 A/dm²
Zinc deposition amount: 0.5 to 22.0 g/m²

As described above, it is possible to use, as a plating bath for use in zinc plating, a bath that uses a sulfate salt as a supply source for zinc ions and is appropriately added with a conductive adjuvant such as ammonium sulfate or sulfuric acid to increase the electrical conductivity of the plating solution. In addition, an additive such as a known gloss agent may be added to the plating bath to form gloss zinc plating or semi-gloss zinc plating.
If a chromium layer is formed as the coating metal layer 70, it can be formed by conducting chromium plating or chromate treatment. Examples of chromium plating conditions are as follows.

Chromium(VI) oxide: 30 to 200 g/L
Sodium fluoride: 1 to 10 g/L
pH: 1.0 or lower
Bath temperature: 35°C to 65°C
Current density: 5 to 50 A/dm²
Chromium deposition amount: 0.05 to 10.0 g/m²

If electro-tin plating is used as the coating metal plating, examples of bath composition for the electro-tin plating and plating conditions are as follows.

Stannous sulfate: 30 to 80 g/L
Phenolsulfonic acid: 30 to 60 g/L
Ethoxylated α-naphthol: 2 to 6 g/L
Ethoxylated α-naphtholsulfonic acid: 4 to 12 g/L
pH: 0.1 to 2.0
Bath temperature: 20°C to 55°C
Current density: 2.5 to 10 A/dm²
Tin deposition amount: 0.2 to 20.0 g/m²

It is to be noted that, in the present embodiment, measurements of the zinc deposition amount, the chromium deposition amount, and the tin deposition amount can be conducted by using a known method such as X-ray fluorescence (XRF) analysis or ICP emission spectroscopy.

<<Examples>>

The present invention will hereinafter be described more specifically by giving examples. A description will first be made regarding measuring methods in the examples.

[Measuring methods of surface texture parameters]

The root mean square height Rq, which is a surface texture parameter on the surface of the roughened nickel layer 50, was measured by following JIS B0601-2013 as described below. Using a laser microscope (manufactured by Olympus Corporation, 3D measuring laser microscope "LEXT OLS5000"), an analysis image of 259 µm × 258 µm visual field was acquired under conditions of a 50× objective lens (lens name: "MPLAPON50XLEXT"). Using an analysis application, denoising and inclination correction as automated correction processing were then conducted on the acquired analysis image. Subsequently, the icon for surface roughness measurement was clicked to perform an analysis, whereby the surface texture parameter was obtained. A root mean square height Rq is a surface texture parameter by a contour curve method, which is obtained by following JIS B0601-2013. With a view to obtaining cross-sectional curves in the above 259 µm × 258 µm visual field, it was assumed that the cross-sectional curves were obtained in a direction perpendicular to the rolling direction (or the rolling direction in continuous rolling) of the base material, and 15 cross-sectional curves were obtained such that they are separated at equal intervals in the above-described vision field. Following JIS B0601-2013, a root mean square height was measured 15 times, and their average value was calculated as the root mean square height Rq. It is to be noted that the analysis was made under no conditions, without setting any of filter criteria (F operation, S filter, L filter) for analysis.
Following JIS B0601-2013 and ISO 25178-2:2012, respective surface texture parameters of a maximum height Sz, Sdr (Developed Interfacial Area Ratio), a relative load length ratio Rmr, a root mean square slope RΔq, a ten-point mean roughness Rzjis, Sdq (Root Mean Square Gradient), and an arithmetical mean height Sa were also obtained.

[Measuring method and evaluation of plating adhesion between base material and roughened nickel layer]

First, one with a self-adhesive tape (manufactured by NICHIBAN Co., Ltd., tradename "CELLOTAPE" (registered trademark)) applied to a base paper sheet was provided as a reference sample. Using a spectrophotometer (manufactured by Konica Minolta, Inc., "CM-5"), its lightness L* and chromaticities a* and b* were measured. It is to be noted that, upon measurement, the CIE 1976 L*a*b* color difference model was used.
After a self-adhesive tape of the same kind as that used for the above-described reference sample was then applied to a surface, on which a roughened nickel layer was formed, as obtained in each example or comparative example so as to cover a range of 24 mm width and 50 mm length, a peel test by the self-adhesive tape so applied was conducted under the guidelines of the pull-off testing method described in JIS H 8504. The self-adhesive tape after the peel test was applied to a base paper sheet of the same kind as that of the above-described reference sample, and its lightness L* and chromaticities a* and b* were measured by using the spectrophotometer as in the above. From the measurement results of the lightness L* and chromaticities a* and b* of the reference sample as measured beforehand and the measurement results of the lightness L* and chromaticities a* and b* of the self-adhesive tape after the peel test, their difference ΔE*ab (ΔE*ab = [(ΔL*)² + ((Δa*)² + ((Δb*)²]^½) was calculated, and an evaluation of the adhesion of the roughened nickel layer was made on the basis of the following criteria. Here, it is possible to determine that the smaller the ΔE*ab, the amount peeled in the peel test is smaller, in other words, the residual ratio of the roughened nickel layer after the peel test is high, and the adhesion with the base material is excellent.

EXCELLENT: ΔE*ab = smaller than 1
GOOD: ΔE*ab = 1 or greater, smaller than 10
POOR: ΔE*ab = 10 or greater

[Resin adhesion (peel test)]

As an evaluation of the adhesion with another member, the adhesion with resin was evaluated. Specifically, a peel test was conducted to evaluate the resin adhesion, and peel strength was obtained. A description will hereinafter be made regarding its measuring method. Firstly, a nickel-plated metal material (30 mm × 150 mm) was provided. A polypropylene film of 140 µm thickness (25 mm × 150 mm) was heat-sealed to the side of the roughened nickel layer by a heat sealer (manufactured by TESTER SANGYO CO., LTD., "TP-701-B"), whereby a specimen was obtained. The heat-sealing temperature was set to 156°C, the heating time was set to 5 seconds, and the heating pressure was set to 0.2 MPa. The resin film was then pulled relative to the base material in a 180° direction at a rate of 50 mm/min by a tension testing machine (manufactured by Shimadzu Corporation, "AGS-X 5kN"), whereby its peel strength was obtained. Owing to the use of the peel test that pulls in the 180° direction, loads from multiple directions after the bonding with the resin were also evaluated. On the basis of the following criteria, an evaluation of the resin adhesion was made.

A: 18 N/25 mm or higher
B: 13 N/25 mm or higher, lower than 18 N/25 mm
C: 10 N/25 mm or higher, lower than 13 N/25 mm (fail)
D: lower than 10 N/25 mm (fail)

[Scratch test (shear durability evaluation)]

As depicted in FIG. 4, a filter paper P (cotton fibers) was placed on a surface of a nickel-plated metal material, the surface being on the side of a roughened nickel layer, a jig J was mounted on the filter paper P (FIG. 4(a)), and a load of 1 kg was applied from above (FIG. 4(b)). By dimensioning a bottom surface of the jig J to 2 cm in diameter, a plane of contact between the surface on the side of the roughened nickel layer and the filter paper P was set to 2 cm in diameter. With the load applied, the jig J was then pulled over 100 mm (FIG. 4(c)). Subsequently, the filter paper P was taken out, and the amount of nickel stuck on the filter paper P was determined by X-ray fluorescence measurement. An evaluation of shear durability was made on the basis of whether or not the deposition amount (g/m²) of nickel on a contact surface of the filter paper P satisfied the criteria to be described hereinafter. When a coating metal layer was formed as a roughened layer on the roughened nickel layer, the determination was made on the basis of the deposition amount (g/m²) of all pieces of metal on the filter paper P. Specifically, when the roughened layer was formed of a roughened nickel layer and a coating tin layer, the evaluation of shear durability was made on the basis of whether or not the total value of a deposition amount (g/m²) of nickel and a deposition amount (g/m²) of tin on the contact surface of the filter paper P satisfied the following criteria.

A: less than 1.0 g/m²
B: 1.0 g/m² or more, less than 2.0 g/m²
C: 2.0 g/m² or more, less than 2.5 g/m² (fail)
D: 2.5 g/m² or more (fail)

A cold-rolled foil (thickness: 200 µm) of low-carbon aluminum-killed steel having a chemical composition presented below was first provided as the base material 20.
C: 0.04 wt%, Mn: 0.32 wt%, Si: 0.01 wt%, P: 0.012 wt%, S: 0.014 wt%, Balance: Fe and inevitable impurities
After electrolytic degreasing and pickling by dipping in sulfuric acid were next carried out on the provided base material, nickel plating was conducted on both sides of the steel foil under the below-described conditions, whereby a nickel-plating layer was formed. It is to be noted that conditions for the nickel plating were set as follows.

(Conditions for Ni plating)

Bath composition:

Nickel sulfate hexahydrate: 250 g/L
Nickel chloride hexahydrate: 45 g/L
Boric acid: 30 g/L
Bath temperature: 60°C
pH: 4.0 to 5.0
Agitation: air agitation or jet agitation
Current density: 10 A/dm²

To the steel foil having the nickel-plating layer formed as described above, continuous annealing, cold rolling, batch annealing (box annealing), and cold rolling were then applied in this order. Specifically, heat treatment was first conducted by continuous annealing under conditions of a heat treatment temperature of 700°C, soaking time of 30 seconds, and a reducing atmosphere. After cold rolling was conducted with a rolling reduction rate of 65% to 75%, heat treatment was next conducted by batch annealing (box annealing) under conditions of a heat treatment temperature of 550°C, soaking time of 7 hours (total of heatup time, soaking time, and cooling time: 80 hours), and a reducing atmosphere. After that, 10% to 20% cold rolling was further applied, whereby a surface-treated steel foil having an iron-nickel alloy layer on both sides was obtained. The thickness of the surface-treated steel foil was 60 µm. When the thickness of the iron-nickel alloy layer was checked by GDS, it was found to be 3.1 µm. When the nickel deposition amount on the surface of the surface-treated steel foil having the above-described iron-nickel alloy layer was measured by using an X-ray fluorescence spectrometer (instrument name: "ZSX100e" manufactured by Rigaku Corporation), it was found to be 13.5 g/m². It is to be noted that the specific measuring method of the nickel deposition amount by the X-ray fluorescence spectrometer is similar to the method described in PCT Patent Publication No. WO2020/017655 , and therefore, its detailed description is omitted herein.
On each surface of the above-described surface-treated steel foil, a nickel layer (hereinafter referred to as the "undercoat nickel layer") to be located between the iron-nickel alloy layer and a roughened nickel layer was formed under the undercoat nickel-plating conditions presented below, whereby the undercoat nickel layer was formed in a deposition amount of 3.9 g/m². It is to be noted that strike nickel-plating was applied in a deposition amount of 0.1 g/m² shortly before the undercoat nickel-plating. The undercoat nickel layer was formed on both sides.

Bath composition:

Nickel sulfate hexahydrate 250 g/L, nickel chloride hexahydrate 45 g/L, boric acid: 30 g/L
pH: 4.0 to 5.0
Bath temperature: 60°C
Current density: 10 A/dm²

On the undercoat nickel layer on the side of each surface, the "roughened nickel layer" was next formed. It is to be noted that the roughened nickel layer was formed by applying the following first roughened nickel-plating and the second roughened nickel-plating.

Concentration of nickel sulfate hexahydrate in plating bath: 10 g/L
Concentration of nickel chloride hexahydrate in plating bath: 10 g/L
Concentration of chloride ions in plating bath: 16.2 g/L
Ratio of nickel ions to ammonium ions in plating bath: nickel ions/ammonium ions (weight ratio) = 0.23
pH: 6.0
Bath temperature: 50°C
Average current density: 22 A/dm²
Electrolysis time: 13.0 seconds

Under the above-described conditions, operations of insertion into the plating bath as a circulating bath, energization, and pull-up from the plating bath were continuously repeated four times in this order to conduct plating treatment.

Bath composition:

Nickel sulfate hexahydrate 250 g/L, nickel chloride hexahydrate 45 g/L, boric acid: 30 g/L
pH: 4.0 to 5.0
Bath temperature: 50°C
Current density: 10 A/dm²
Deposition amount: 2.1 g/m²

Values of Rq and Sz on an outermost surface formed on the roughened nickel layer of the nickel-plated metal material are presented in Table 1. Values of individual surface texture parameters are also presented in Table 1. Using the laser microscope (manufactured by Olympus Corporation, 3D measuring laser microscope "LEXT OLS5000"), the surface texture parameters were measured under the conditions of the 50× objective lens of OLS5000. The adhesion between the base material and the roughened nickel layer, the resin adhesion, and the amount of nickel deposited on a filter paper in a scratch test were also measured. The individual measurement results or evaluation results based on the measurement results are presented in Table 1.

Example 1 was followed except that, as presented in Table 2, the deposition amounts of roughened nickel layers obtained by the first roughened nickel-plating and second roughened nickel-plating were different. The results are presented in Table 1 and Table 2.

Example 1 was followed except that, as presented in Table 2, the average current density and electrolysis time in the first roughened nickel-plating, and the deposition amounts of roughened nickel layers obtained by the first roughened nickel-plating and second roughened nickel-plating were different. The results are presented in Table 1 and Table 2.

Example 1 was followed except that, as presented in Table 2, the number of plating bath insertions, average current density, and electrolysis time in the first roughened nickel-plating, and the deposition amounts of roughened nickel layers obtained by the first roughened nickel-plating and second roughened nickel-plating were different. The results are presented in Table 1 and Table 2.

Example 1 was followed except that, as presented in Table 2, the deposition amounts of roughened nickel layers obtained by the first roughened nickel-plating and second roughened nickel-plating in the first roughened nickel-plating were different. The results are presented in Table 1 and Table 2.

Example 1 was followed except that, as presented in Table 2, the number of plating bath insertions, average current density, and electrolysis time in the first roughened nickel-plating, and the deposition amount of a roughened nickel layer obtained by the first roughened nickel-plating were different. It is to be noted that the second roughened nickel-plating was not conducted. The results are presented in Table 1 and Table 2.

A 60 µm-thick cold-rolled steel foil of low-carbon aluminum-killed steel was provided as a base material 20. Unlike in Example 1, the treatment before the undercoat nickel-plating was not conducted on the base material 20. Specifically, without conducting, on the base material 20, the nickel plating and the continuous annealing, cold rolling, batch annealing (box annealing), cold rolling, and strike nickel-plating after the nickel plating, an undercoat nickel layer with the deposition amount presented in Table 1 was formed by using the undercoat nickel-plating conditions in Example 1. Next, a "roughened nickel layer" was formed on the undercoat nickel layer. At that time, the first roughened nickel-plating conditions were set as described below. On the other hand, the second roughened nickel-plating conditions were set to be the same as those in Example 1. The deposition amount was set as in Table 1. Otherwise, Example 1 was followed. The results are presented in Table 1 and Table 2.

Concentration of nickel sulfate hexahydrate in plating bath: 10 g/L
Concentration of nickel chloride hexahydrate in plating bath: 10 g/L
Concentration of chloride ions in plating bath: 3.0 g/L
Ratio of nickel ions to ammonium ions in plating bath: nickel ions/ammonium ions (weight ratio) = 0.17
pH: 6.0
Bath temperature: 50°C
Average current density: 15 A/dm²
Electrolysis time: 60.5 seconds

Under the above-described conditions, operations of insertion into the plating bath, energization, and pull-up from the plating bath were continuously repeated once in this order to conduct plating treatment. The circulation in the plating bath was omitted, and the air agitation alone was conducted.
<Comparative Example 6>
The first roughened nickel-plating conditions were set as described below. Further, the nickel deposition amounts by the first roughened nickel-plating and second roughened nickel-plating were set as presented in Table 1. Otherwise, Comparative Example 5 was followed. The results are presented in Table 1 and Table 2.

Concentration of nickel sulfate hexahydrate in plating bath: 20 g/L
Concentration of ammonium sulfide in plating bath: 20 g/L
Concentration of chloride ions in plating bath: 0 g/L
Ratio of nickel ions to ammonium ions in plating bath: nickel ions/ammonium ions (weight ratio) = 0.84
pH: 6.2
Bath temperature: 30°C
Average current density: 10 A/dm²
Electrolysis time: 18 seconds

[Table 1]

	Rq[µm]	Sz[µm]	Sdr[%]	Rmr[%]	RΔq[°]	Rzjis [µm]	Sdq[%]	Sa[µm]	EVALUATION OF PLATING ADHESION	RESIN ADHESION (PEEL TEST)		SHEAR DURABILITY (SCRATCH TEST)
	Rq[µm]	Sz[µm]	Sdr[%]	Rmr[%]	RΔq[°]	Rzjis [µm]	Sdq[%]	Sa[µm]	EVALUATION OF PLATING ADHESION	PEEL SRENGTH [N/25mm]	EVALUATION	DEPOSITION AMOUNT [g/m²]	EVALUATION
Example 1	0.50	5.99	34	82.0	39.5	2.55	1.16	0.39	EXCELLENT	42.5	A	0.72	A
Example 2	0.76	9.51	36	38.8	48.7	3.65	1.60	0.61	EXCELLENT	25.7	A	0.72	A
Example 3	0.52	5.33	41	85.2	35.3	2.26	0.97	0.41	EXCELLENT	27.5	A	0.04	A
Example 4	0.52	7.76	68	77.9	36.4	2.47	1.02	0.42	EXCELLENT	47.3	A	0.31	A
Example 5	0.49	5.01	43	81.5	38.3	2.38	1.12	0.39	EXCELLENT	20.1	A	0.48	A
Example 6	0.55	6.01	44	76.0	40.1	2.65	1.17	0.45	EXCELLENT	13.5	B	0.08	A
Example 7	0.64	6.52	36	74.2	36.8	2.53	1.02	0.52	EXCELLENT	15.8	B	0.00	A
Example 8	0.39	4.54	29	91.0	32.7	1.95	0.89	0.32	EXCELLENT	16.5	B	0.16	A
Example 9	0.53	6.06	47	74.7	41.5	2.61	1.22	0.42	EXCELLENT	15.0	B	0.00	A
Example 10	0.31	5.43	19	55.6	26.3	1.53	0.68	0.23	EXCELLENT	37.0	A	0.55	A
Example 11	0.29	5.14	18	54.2	26.2	1.53	0.67	0.22	EXCELLENT	22.5	A	0.20	A
Example 12	0.35	4.20	17	83.5	29.4	1.77	0.77	0.28	EXCELLENT	23.0	A	0.30	A
Comparative Example 1	1.00	8.94	92	18.2	55.8	4.67	2.06	0.82	EXCELLENT	50.0	A	2.90	D
Comparative Example 2	1.09	11.54	103	18.9	58.3	5.06	2.24	0.89	EXCELLENT	39.7	A	5.33	D
Comparative Example 3	0.91	8.66	79	29.1	53.0	4.19	1.81	0.73	EXCELLENT	59.4	A	6.49	D
Comparative Example 4	0.28	4.12	5	9.9	13.9	0.98	0.33	0.24	EXCELLENT	0.0	D	0.00	A
Comparative Example 5	1.25	12.17	105	10.7	58.5	5.64	2.28	1.03	EXCELLENT	43.9	A	2.81	D
Comparative Example 6	0.30	3.30	11	32.1	19.9	1.25	0.49	0.26	EXCELLENT	8.5	D	0.00	A

[Table 2]

	STRIKE NICKEL-PLATING CONDITIONS	UNDERCOAT NICKEL-PLATING CONDITIONS	FIRST ROUGHENED NICKEL-PLATING CONDITIONS							SECOND ROUGHENED NICKEL-PLATING CONDITIONS	NICKEL DEPOSITION AMOUNT IN ROUGHENED NICKEL LAYER*1 [g/m²]	TOTAL DEPOSITION AMOUNT OF NICKEL*2 [g/m²]
	NICKEL DEPOSITION AMOUNT [g/m²]	NICKEL DEPOSITION AMOUNT [g/m²]	NUMBER OF PLATING BATH INSERTIONS	AVERAGE CURRENT DENSITY [A/dm²]	ELECTROLYSIS TIME [sec]	pH	TEMPERATURE [°C]	CIRCULATED/ NOT CIRCULATED	NICKEL DEPOSITION AMOUNT [g/m²]	NICKEL DEPOSITION AMOUNT [g/m²]	NICKEL DEPOSITION AMOUNT IN ROUGHENED NICKEL LAYER*1 [g/m²]	TOTAL DEPOSITION AMOUNT OF NICKEL*2 [g/m²]
Example 1	0.1	3.9	4	22	13.0	6.0	50	CIRCULATED	6.4	2.1	8.6	26.1
Example 2	0.1	3.9	4	22	14.0	6.0	50	CIRCULATED	6.8	1.1	7.9	25.4
Example 3	0.1	3.9	4	23	13.5	6.0	50	CIRCULATED	6.9	4.5	11.3	28.8
Example 4	0.1	3.9	5	23	17.5	6.0	50	CIRCULATED	9.0	6.2	15.2	32.7
Example 5	0.1	3.9	4	23	11.3	6.0	50	CIRCULATED	5.8	1.3	7.2	24.7
Example 6	0.1	3.9	5	20	18.0	6.0	50	CIRCULATED	8.1	4.0	12.1	29.6
Example 7	0.1	3.9	4	22	12.0	6.0	50	CIRCULATED	6.0	4.3	10.2	27.7
Example 8	0.1	3.9	3	23	11.5	6.0	50	CIRCULATED	6.0	2.7	8.7	26.2
Example 9	0.1	3.9	8	16	31.0	6.0	50	CIRCULATED	11.0	4.3	15.3	32.8
Example 10	0.1	3.9	3	15	12.0	6.0	50	CIRCULATED	3.9	0.0	3.9	21.4
Example 11	0.1	3.9	4	23	17.8	6.0	50	CIRCULATED	5.7	0.6	6.3	21.1
Example 12	0.1	3.9	4	23	17.8	6.0	50	CIRCULATED	6.2	1.0	7.3	22.1
Comparative Example 1	0.1	3.9	8	23	23.0	6.0	50	CIRCULATED	11.7	5.3	17.0	34.5
Comparative Example 2	0.1	3.9	8	19	35.5	6.0	50	CIRCULATED	15.1	5.3	20.5	38.0
Comparative Example 3	0.1	3.9	8	22	22.0	6.0	50	CIRCULATED	10.8	2.7	13.5	31.0
Comparative Example 4	0.1	3.9	3	12	16.5	6.0	50	CIRCULATED	4.4	2.7	7.1	24.6
Comparative Example 5	0.0	8.9	1	15	60.5	6.0	50	NOT CIRCULATED	13.8	0.3	14.1	23.0
Comparative Example 6	0.0	8.9	1	10	18.0	6.2	30	NOT CIRCULATED	1.9	5.6	7.5	16.4

*1 The nickel deposition amount in the roughened nickel layer indicates the total amount of the deposition amount in the first roughened nickel-plating step and the deposition amount in the second roughened nickel-plating step.
*2 The total deposition amount of nickel indicates the nickel deposition amount per side in the nickel-plated steel sheet after completion of all the steps.

A 60 µm-thick cold-rolled steel foil of low-carbon aluminum-killed steel was provided as a base material 20. Unlike in Example 1, the treatment before the undercoat nickel-plating was not conducted on the base material 20. Specifically, without conducting, on the base material 20, the nickel plating and the continuous annealing, cold rolling, batch annealing (box annealing), cold rolling, and strike nickel-plating after the nickel plating, an undercoat nickel layer with the deposition amount presented in Table 1 was formed by using the undercoat nickel-plating conditions in Example 1. Next, the first roughened nickel-plating was conducted under the conditions presented in Table 4. Subsequently, instead of the second roughened nickel-plating in Example 1, coating treatment was conducted under the coating metal layer forming conditions described hereinafter, whereby a roughened layer having a coating metal layer made of tin (hereinafter also called a "coating tin layer") was formed on a roughened nickel layer on one side. The deposition amount was set as presented in Table 4. Otherwise, Example 1 was followed.
Therefore, the roughened layer in the present Example was formed by the first roughened nickel-plating step and the coating metal layer forming step, which formed the coating metal layer, under the conditions presented in Table 4. A coating treatment step was executed by using tin plating. The results are presented in Table 3 and Table 4.

Stannous sulfate: 80 g/L
Phenolsulfonic acid: 60 g/L
Ethoxylated α-naphthol: 3 g/L
Ethoxylated α-naphtholsulfonic acid: 3 g/L
pH: 1.0 (An adjustment with sulfuric acid was conducted.)
Bath temperature: 40°C
Current density: 5.0 A/dm²
Electrolysis time: 5.0 seconds

The coating tin layer was obtained under the above-described conditions.

Example 13 was followed except that the tin deposition amount in the coating metal layer obtained by the coating treatment step was changed by adjusting the electrolysis time. The results are presented in Table 3 and Table 4.

Example 13 was followed except that the nickel deposition amount in the roughened nickel layer obtained by the first roughened nickel-plating and the tin deposition amount in the coating metal layer obtained by the coating treatment step were changed by adjusting the electrolysis time. The results are presented in Table 3 and Table 4.

[Table 3]

	Rq[µm]	Sz[µm]	Sdr[%]	Rmr[%]	RΔq[°]	Rzjis [µm]	Sdq[%]	Sa[µm]	EVALUATION OF PLATING ADHESION	RESIN ADHESION (PEEL TEST)		SHEAR DURABILITY (SCRATCH TEST)
	Rq[µm]	Sz[µm]	Sdr[%]	Rmr[%]	RΔq[°]	Rzjis [µm]	Sdq[%]	Sa[µm]	EVALUATION OF PLATING ADHESION	PEEL SRENGTH [N/25mm]	EVALUATION	NICKEL DEPOSITION AMOUNT [g/m²]	TIN DEPOSITION AMOUNT [g/m²]	TOTAL DEPOSITION AMOUNT [g/m²]	EVALUATION
Example 13	0.46	7.78	19	74.9	28.3	1.96	0.70	0.37	EXCELLENT	50.2	A	0.88	0.8	1.68	B
Example 14	0.50	5.19	18	75.4	23.2	1.59	0.55	0.41	EXCELLENT	16.5	B	0.00	0.0	0.00	A
Example 15	0.74	8.28	59	37.5	47.5	3.55	1.50	0.58	EXCELLENT	24.3	A	0.66	0.31	0.97	A
Comparative Example 7	1.27	12.48	107	9.4	60.7	5.72	2.44	1.01	EXCELLENT	20.6	A	1.80	0.81	2.61	D

[Table 4]

	STRIKE NICKEL-PLATING CONDITIONS	UNDERCOAT NICKEL-PLATING CONDITIONS	FIRST ROUGHENED NICKEL-PLATING CONDITIONS							TIN PLATING CONDITIONS	NICKEL DEPOSITION AMOUNT IN ROUGHENED NICKEL LAYER*3 [g/m²]	TOTAL DEPOSITION AMOUNT OF NICKEL*2 [g/m²]
	NICKEL DEPOSITION AMOUNT [g/m²]	NICKEL DEPOSITION AMOUNT [g/m²]	NUMBER OF PLATING BATH INSERTIONS	AVERAGE CURRENT DENSITY [A/dm²]	ELECTROLYSIS TIME [sec]	pH	TEMPERATURE [°C]	CIRCULATED/ NOT CIRCULATED	NICKEL DEPOSITION AMOUNT [g/m²]	TIN DEPOSITION AMOUNT [g/m²]	NICKEL DEPOSITION AMOUNT IN ROUGHENED NICKEL LAYER*3 [g/m²]	TOTAL DEPOSITION AMOUNT OF NICKEL*2 [g/m²]
Example 13	0.0	2.7	4	20	15.0	6.0	50	CIRCULATED	6.7	0.9	6.7	9.4
Example 14	0.0	2.7	4	20	15.0	6.0	50	CIRCULATED	6.7	1.8	6.7	9.4
Example 15	0.0	2.7	4	20	27.5	6.0	50	CIRCULATED	9.6	7.2	9.6	12.3
Comparative Example 7	0.0	2.7	1	20	37.5	6.0	50	NOT CIRCULATED	11.5	14.4	11.5	14.2

*3 The nickel deposition amount in the roughened nickel layer when the coating metal layer was included indicates the total amount of the deposition amount in the roughened nickel-plating step before the formation of the coating metal layer.
*2 The total deposition amount of nickel indicates the nickel deposition amount per side in the nickel-plated steel sheet after completion of all the steps.

Examples 1 to 15 have been confirmed to be preferred in all characteristics including not only plating adhesion but also adhesion with another member and shear durability, as the resin adhesion (peel test) was 13N/25 mm or higher and the deposition amount in the evaluation of shear durability by the scratch test was less than 2.0 g/m². In Comparative Examples 1 to 3, Comparative Example 5, and Comparative Example 7, on the other hand, Rq fell outside the prescribed range, thereby failing to achieve the object from the viewpoint of shear durability. In Comparative Example 4 and Comparative Example 6, either Rq or Sz fell outside the range, thereby failing to achieve the object from the viewpoint of adhesion with another member.

[Industrial Applicability]

Various modifications can be made to the above-described embodiments and the individual examples within a scope not departing from the spirit of the present invention. Without being limited to collectors for secondary batteries, the nickel-plated metal materials in this disclosure can be suitably used for members required to have high adhesion with other members (active materials, resins, and the like) in battery members, members constituting electric/electronic related devices, interior members for automobiles and constructions, automobile members such as gaskets, and sliding members.

[Reference Signs List]

100, 200, 300:: Nickel-plated metal material
20:: Base material
40:: Intermediate metal layer
50:: Roughened nickel layer
70:: Coating metal layer

Claims

A nickel-plated metal material comprising:
a base material made of metal; and

a roughened nickel layer formed on at least one side on the base material, wherein,

on a surface of the nickel-plated metal material, the surface being on a side of the roughened nickel layer, a root mean square height Rq is 0.29 µm or greater and 0.90 µm or smaller, and a maximum height Sz is greater than 3.5 µm and 10.0 µm or smaller.
The nickel-plated metal material according to claim 1, wherein Sdr (Developed Interfacial Area Ratio) on the surface on the side of the roughened nickel layer is 16% to 75%.
The nickel-plated metal material according to claim 1 or 2, wherein a relative load length ratio Rmr on the surface on the side of the roughened nickel layer is 33% to 95%.
The nickel-plated metal material according to claim 1 or 2, wherein a root mean square slope RΔq on the surface on the side of the roughened nickel layer is 15 to 50 degrees.
The nickel-plated metal material according to claim 1 or 2, wherein a ten-point mean roughness Rzjis on the surface on the side of the roughened nickel layer is 1.0 to 6.0 µm.
The nickel-plated metal material according to claim 1 or 2, wherein a deposition amount of nickel in the roughened nickel layer is 3.5 to 19.0 g/m².
The nickel-plated metal material according to claim 1 or 2, wherein the nickel-plated metal material has an iron-nickel alloy layer and/or a nickel layer between the base material and the roughened nickel layer.
The nickel-plated metal material according to claim 7, wherein a total deposition amount of nickel in the roughened nickel layer and the nickel layer is 4.8 to 32.8 g/m².
The nickel-plated metal material according to claim 7, wherein a total deposition amount of nickel in the roughened nickel layer, the nickel layer, and the iron-nickel alloy layer is 4.5 to 55.1 g/m².
The nickel-plated metal material according to claim 1 or 2, wherein the roughened nickel layer is formed on an outermost surface.
The nickel-plated metal material according to claim 1 or 2, comprising:
on the roughened nickel layer, a coating metal layer formed of zinc, tin, or chromium, or an alloy thereof.