Plated member and fastener stringer

Abstract

This plated member includes: a base material (83) containing at least one base material metal element; and plating layers (84) formed on the base material (83). The plating layers (84) include first and second plating layers (81, 82) formed on the base material (83) in the stated order. The first and second plating layers (81, 82) each contain at least a first plating layer metal element which is the same metal element as the base material metal element, and a second plating layer metal element which is a metal element different from the base material metal element. The element proportion of the first plating layer metal element continuously decreases away from the base material (83) at least over the total layer thickness of the first and second plating layers (81, 82). The element proportion of the second plating layer metal element continuously increases away from the base material (83) at least over the total layer thickness of the first and second plating layer (81, 82). The second plating layer (82) is observable as being distinct from the first plating layer (81) in a first TEM image as a layer having crystal grains larger than crystal grains in the first plating layer (81).

Description

Plating materials and fastener stringers

[0001] The present disclosure relates to plating materials and fastener stringers.

[0002] Patent Document 1 discloses a plating layer (see reference numeral 52) formed on a substrate made of brass (CuZn), as shown in Figure 23 of the same document, and as shown in Figure 4 of the same document, the element ratio of the substrate metal elements (Cu, Zn) continuously decreases with increasing distance from the substrate, and the element ratio of the plating layer metal element (Sn) continuously increases with increasing distance from the substrate. Figure 27 of Patent Document 1 shows the area distribution of crystal grains in the example shown in Figure 23 (see Em in the same figure), and the crystal grains are distributed within a narrow area range.

[0003] Patent Document 2 discloses electroplating a substrate such as a button by placing it in a plating tank, and in particular, discloses using a permanent magnet to cause magnetic media to flow together with the substrate, such as a button, and electroplating is performed while the magnetic media collide with the substrate, such as a button.

[0004] International Publication No. 2018 / 190202 International Publication No. 2018 / 189916

[0005] The plating layer disclosed in Patent Document 1 has higher adhesion to the substrate than conventional plating layers and is useful in a variety of applications. However, forming the plating layer disclosed in Patent Document 1 tends to require a long electroplating process. This is thought to be due in part to the fact that the plating layer collides with magnetic media and / or other plating materials during the electroplating process, resulting in impact and suppression of its growth (although this does not exclude other additional or alternative factors).

[0006] It is also conceivable to form the plating layer disclosed in Patent Document 1 as a thin layer and then carry out an additional conventional electroplating step without using magnetic media. However, in this case, different types of electroplating steps must be carried out successively, making it difficult to shorten the time required for the electroplating step.

[0007] As can be seen from the above non-limiting illustrative examples, further improvements are desired for plating layers in which the element ratios of the base metal elements and the plating layer metal elements change continuously.

[0008] A plated product according to one embodiment of the present disclosure includes a substrate containing at least one base metal element and a plating layer formed on the substrate. The plating layer includes first and second plating layers formed in this order on the substrate. Each of the first and second plating layers includes at least a first plating layer metal element that is the same metal element as the base metal element and a second plating layer metal element that is a different metal element from the base metal element. The elemental ratio of the first plating layer metal element continuously decreases with increasing distance from the substrate over at least the total thickness of the first and second plating layers, and the elemental ratio of the second plating layer metal element continuously increases with increasing distance from the substrate over at least the total thickness of the first and second plating layers. The second plating layer can be observed distinctly from the first plating layer in a first transmission electron microscope (TEM) image as a layer with larger crystal grains than those of the first plating layer.

[0009] A fastener stringer according to another embodiment of the present disclosure includes a fastener tape and a plurality of fastener elements attached to side edges of the fastener tape at a predetermined pitch. Each fastener element of the plurality of fastener elements includes a substrate containing at least one base metal element and a plating layer formed on the substrate. The plating layer includes first and second plating layers formed in this order on the substrate. Each of the first and second plating layers includes at least a first plating layer metal element that is the same metal element as the base metal element and a second plating layer metal element that is a different metal element from the base metal element. The elemental ratio of the first plating layer metal element continuously decreases with increasing distance from the substrate over at least the total thickness of the first and second plating layers, and the elemental ratio of the second plating layer metal element continuously increases with increasing distance from the substrate over at least the total thickness of the first and second plating layers. The second plating layer can be distinguished from the first plating layer in a transmission electron microscope (TEM) image as a layer with larger crystal grains than the crystal grains of the first plating layer.

[0010] In some embodiments, the first plating layer is a layer made up of a plurality of densely packed first crystal grains, and the second plating layer is a layer made up of a plurality of densely packed second crystal grains, each of the plurality of first crystal grains having a width less than 100 nm, and each of the plurality of second crystal grains having a width greater than 100 nm.

[0011] In some embodiments, when a rectangular frame is applied to the second crystal grains in the first TEM image, and the area of ​​the second crystal grains is determined to be half the area of ​​the rectangular frame, the average area of ​​the second crystal grains in the first TEM image is 10,000 nm 2 Above, 50000nm 2 or more, or 100,000 nm 2 That's all.

[0012] In some embodiments, when a rectangular frame is applied to the first crystal grains in the first TEM image or a second TEM (Transmission Electron Microscope) image having a higher magnification, and the area of ​​the first crystal grains is determined as half the area of ​​the rectangular frame, the average area of ​​the first crystal grains in the second TEM image is 2000 nm ２ or less than 1000 nm 2 The following is it.

[0013] In some embodiments, the average area of ​​the second grains in the first TEM image is more than 5 or 10 times the average area of ​​the first grains in the second TEM image, and the average areas of the first and second grains are expressed in the same unit of nm 2 This is expressed as:

[0014] In some embodiments, the variance of the area of ​​the first crystal grains in the second TEM image is 1 / 1000 or less (typically 1 / 9000 or less, 1 / 8000 or less, 1 / 7000 or less, 1 / 6000 or less, 1 / 5000 or less, 1 / 4000 or less, 1 / 3000 or less, or 1 / 2000 or less) of the variance of the area of ​​the second crystal grains in the first TEM image, and / or the standard deviation of the area of ​​the first crystal grains in the second TEM image is 1 / 10 or less (typically 1 / 60 or less, 1 / 50 or less, 1 / 40 or less, 1 / 30 or less, and 1 / 20 or less) of the standard deviation of the area of ​​the second crystal grains in the first TEM image.

[0015] In some embodiments, no planar interface is observed between the first plating layer and the second plating layer in the first TEM image, and / or no planar interface is observed between the substrate and the first plating layer in the first TEM image.

[0016] In some embodiments, the thickness of the first plating layer is less than the thickness of the second plating layer.

[0017] In some embodiments, the thickness of the first plating layer is 200 nm or less, or 150 nm or less.

[0018] In some embodiments, the thickness of the second plating layer is in the range of 100 to 1000 nm.

[0019] In some embodiments, the first plating layer is formed closer to the substrate than the intersection of the plot line of the element ratio of the metal elements in the first plating layer and the plot line of the element ratio of the metal elements in the second plating layer in the depth direction from the surface of the plating material toward the substrate, and the distance between the intersection and the first plating layer may be 50 nm or more.

[0020] In some embodiments, the first plating layer metallic element is copper, the second plating layer metallic element is tin, and the first plating layer includes a speculum alloy.

[0021] In some embodiments, the surface of the second plating layer has numerous dents.

[0022] In some embodiments, the plating material is a fastener element attached to the fastener tape, the fastener element having at least a pair of legs and a head to which the pair of legs are connected, and the first plating layer is formed non-uniformly on different surfaces of the fastener element.

[0023] In some embodiments, the plating material is a fastener element attached to the fastener tape, the fastener element including at least a partially textured surface.

[0024] In some embodiments, the fastener element has a main surface oriented along the tape surface that defines the thickness of the fastener tape, and the second plating layer, the first plating layer, and the substrate are formed in this order from the main surface toward the fastener tape.

[0025] In some embodiments, the fastener element includes a pair of legs that sandwich the fastener tape, and each leg of the pair of legs includes a front side surface connected to the front edge of the main surface and a rear side surface connected to the rear edge of the main surface, and the second plating layer, the first plating layer, the substrate, the first plating layer, and the second plating layer are formed in this order between the front side surface and the rear side surface.

[0026] According to one aspect of the present disclosure, it is possible to provide further improvements to a plating layer in which the element ratios of the base metal elements and the plating layer metal elements change continuously.

[0027]

[0023] FIG. 1 is a schematic diagram of a slide fastener in which a plated material according to one embodiment of the present disclosure is embodied as each fastener element.

[0024] FIG. 1 is a partially enlarged schematic diagram of FIG. 1 showing a state in which left and right fastener elements are alternately engaged, and also shows a state in which the engaging protrusion of the rear fastener element is engaged with the engaging recess of the front fastener element with respect to the engaged left and right fastener elements.

[0025] FIG. 1 is a schematic perspective view of one fastener element.

[0026] FIG. 1 is a partially enlarged schematic cross-sectional view of a fastener element.

[0027] FIG. 1 is a schematic graph showing the change in the ratio of each element in the depth direction from the surface of a plated material according to one embodiment of the present disclosure to its interior.

[0028] FIG. 1 is a TEM (Transmission Electron Microscope) image (observation magnification: 50,000 times, observation field: 2.5 μm × 1.9 μm) showing a cross section of the same plated material as FIG. 5, in which a dotted line has been added to indicate a boundary between the substrate and the first plating layer, a dotted line has been added to indicate a boundary between the first plating layer and the second plating layer, and an enlarged portion of the enlarged image of FIG. 7 has been added within a dotted frame.

[0029] FIG. 1 is an enlarged image of the portion within the dotted frame of the TEM image shown in FIG. 6. 7 is a TEM image in which a rectangular frame is actually applied to calculate the area of ​​the second crystal grains. FIG. 8 is a TEM image in which a rectangular frame is actually applied to calculate the area of ​​the second crystal grains. FIG. 9 is a TEM image in which a rectangular frame is actually applied to calculate the area of ​​the first crystal grains. FIG. 10 is a TEM image in which a rectangular frame is actually applied to calculate the area of ​​the first crystal grains. FIG. 11 is a TEM image in which a rectangular frame is actually applied to calculate the area of ​​the first crystal grains. FIG. 12 is a graph showing the distribution of crystal grains in the same plated material as in FIGS. 5 and 6. FIG. 13 is an image showing the surface condition of a plated material according to an embodiment of the present disclosure. FIG. 14 is an image showing the surface condition of a plated material according to an embodiment of the present disclosure. FIG. 15 is an image showing the bottom surface of an engagement recess in a plated material according to an embodiment of the present disclosure. FIG. 16 is a schematic diagram of an electroplating apparatus according to an embodiment of the present disclosure. FIG. 17 is a schematic diagram showing the movement of a magnetic medium in response to an alternating magnetic field. FIG. 18 is a schematic diagram of a magnetic rotating part. FIG. 19 is a schematic diagram showing that the magnetic rotating part is housed in a magnetically permeable housing. It is a schematic diagram showing a frame for arranging an anode. It is a schematic diagram of a front and back reversing unit that turns over a fastener chain. It is a schematic diagram showing a modified example of an electroplating apparatus.10A and 10B are schematic diagrams showing another modified example of the electroplating apparatus, and FIG. 10C are schematic diagrams showing yet another modified example of the electroplating apparatus, and FIG. 10D are schematic diagrams showing yet another modified example of the electroplating apparatus.

[0028] Various embodiments and features will be described below with reference to the drawings. Those skilled in the art will be able to combine the various embodiments and / or features without the need for excessive explanation, and will also be able to understand the synergistic effects of such combinations. Duplicate descriptions between embodiments will generally be omitted. The reference drawings are primarily intended to describe the invention, and are simplified for ease of illustration. Each feature is not only effective for the fastener element disclosed in this application as a non-limiting example of a plating material, but is understood as a universal feature that can also be applied to various other metal parts not disclosed in this specification.

[0029] The plating material and its features according to the present disclosure will be described below in relation to, but not limited to, the metal fastener elements 4a and 4b included in the slide fastener 1 shown in Fig. 1. The plating material can be embodied as a variety of metal parts for clothing, such as the metal slider 7 included in the slide fastener 1 or metal buttons unrelated to the slide fastener, or as metal parts from other fields, such as fasteners such as screws and bolts.

[0030] The plating material according to the present disclosure will be primarily described as being obtained by conveying a substrate through an alternating magnetic field in a plating solution in which multiple magnetic media move randomly, electrically connecting the substrate to a cathode via the magnetic media, and then electroplating the substrate. However, this should not be limited to plating using the electroplating apparatus described below according to the present disclosure. The specific configuration of the electroplating apparatus will vary depending on the type of plating material (e.g., fastener element, slider, or button). Frankly, it is understood that the plating material according to the present disclosure can be produced using various other electroplating apparatuses and methods, not limited to the electroplating apparatus and method illustrated herein.

[0031] Each magnetic media continues to rotate and rotate in response to the alternating magnetic field. Therefore, while the electrical connection of the substrate to the cathode electrode via a single magnetic media is instantaneous, adding multiple magnetic media to the plating solution allows the substrate to be continuously maintained at the cathode potential. The magnetic media collide with the surface of the substrate and with the surface of the plating layer growing on the substrate, which is thought to cause a distribution of crystal grain sizes in the growing plating layer. As described below, discontinuities occur in the area distribution of crystal grains in the plating layer of the present application. While this may not necessarily be optimal from the perspective of achieving the highest quality plating layer, it is advantageous from the perspective of achieving both higher plating layer adhesion and a shorter electroplating process. This point will become more clear from the explanation below.

[0032] TEM images are used as cross-sectional images to calculate the area of ​​the crystal grains. TEM images are acquired to capture a cross-section of the plating layer in the thickness direction of the plating layer. TEM images were acquired using a transmission electron microscope (model number: TalosF200X) manufactured by Japan FI, Inc. and a scanning transmission electron microscope (model number: HD-2300A) manufactured by Hitachi High-Technologies Corporation. The observation magnification was 50,000 to 1,000,000 times. (Note that even at unity magnification, the definition of magnification may differ depending on the transmission electron microscope. Therefore, strictly speaking, it is appropriate to evaluate the degree of magnification by the width of the observation field. In light of this, the observation field is also listed in this specification.) The TEM images in Figures 6 and 7 were acquired using the HD-2300A.

[0033] The slide fastener 1 will be described with reference to Figures 1 to 3. The slide fastener 1 has a pair of left and right fastener stringers 2a, 2b, and a slider 7 that moves forward to connect them and moves backward to release them. The fastener stringers 2a, 2b have fastener elements 4a, 4b attached at a predetermined pitch to opposing side edges of fastener tapes 3a, 3b. The slide fastener 1 has left and right front stops that define the foremost position of the slider 7 and one rear stop that defines the rearmost position of the slider 7, but these can be omitted. The slider 7 is a typical type having an upper blade, a lower blade, and connecting posts that connect them, and a detailed description thereof will be omitted.

[0034] The slide fastener 1 extends longitudinally in the front-to-rear direction with a predetermined left-to-right width, and has high flexibility overall. The same is true for the fastener stringers 2a, 2b. The slide fastener 1 is attached and fixed to various articles such as clothing, bags, and shoes, and provides an opening in the article that can be opened and closed by opening and closing the slide fastener itself. The fastener tapes 3a, 3b are woven or knitted fabrics with high flexibility, and core cords CY for fixing the fastener elements 4a, 4b are provided at their side edges. The width directions of the slide fastener 1, fastener stringers 2a, 2b, and fastener tapes 3a, 3b coincide with the left-to-right direction.

[0035] The fastener elements 4a, 4b are formed by electroplating a metal substrate. The fastener elements 4a, 4b include an engaging head 21 and a pair of legs 22, 23 that extend from the engaging head 21 in the same direction (along the width direction of the fastener tapes 3a, 3b) and sandwich the fastener tapes 3a, 3b. The engaging head 21 has an engaging protrusion 46 on its front side that protrudes forward on the central axis CX of the slide fastener 1, and an engaging recess 47 on its rear side that is recessed forward on the central axis CX. The engaging protrusion 46 narrows as it extends forward until it reaches its tip surface 46j. The engaging recess 47 narrows as it extends forward until it reaches its bottom surface 47j. The complementary shapes of the engaging protrusion 46 and the engaging recess 47 promote smooth and strong engagement between the left and right fastener elements 4a, 4b. The fastener elements 4a, 4b are not limited to the above-described structure. For example, the engaging head 21 may have a structure having a pair of engaging heads protruding on both the front and rear sides on the central axis CX of the slide fastener 1 .

[0036] When an observer views the slide fastener 1 from the front (see FIG. 1), they can observe the alternatingly arranged main surfaces 51 of the left and right fastener elements 4a, 4b. Each main surface 51 of the fastener elements 4a, 4b is a surface oriented along (e.g., parallel to) the upper or lower tape surface of the fastener tapes 3a, 3b, i.e., the tape surface that defines the thickness of the fastener tapes 3a, 3b. Each main surface 51 of the fastener elements 4a, 4b can extend in the width direction of the slide fastener 1 from the side edge of the fastener tapes 3a, 3b until it intersects with the central axis CX of the slide fastener 1.

[0037] As described above, the fastener elements 4a, 4b are formed by electroplating a metal substrate, and one purpose of this is to give the fastener elements 4a, 4b a desired metallic color, particularly to give the desired metallic color to the main surfaces 51. By uniformly electroplating the main surfaces 51 of the fastener elements 4a, 4b, the appearance quality of the slide fastener 1 is improved. Of course, electroplating can also be performed for an additional or alternative purpose, such as protecting the substrate with a plating layer. The main surfaces 51 of the fastener elements 4a, 4b include the main surface portion 51a formed on the engaging head 21 and the main surface portions 51b formed on the leg portions 22, 23.

[0038] 2 and 3, the leg portions 22, 23 have contact surfaces 22t, 23t that contact the fastener tapes 3a, 3b, and main surfaces 22m, 23m that are located on the opposite side of the contact surfaces 22t, 23t and away from the tape surfaces of the fastener tapes 3a, 3b. The contact surfaces 22t, 23t are curved surfaces that receive the core cords at the side edges of the fastener tapes 3a, 3b. The main surfaces 22m, 23m are flat surfaces oriented approximately parallel to the tape surfaces of the fastener tapes 3a, 3b.

[0039] A front side surface 52 is connected to the front edges of the main surfaces 22m, 23m, and a rear side surface 53 is connected to the rear edges of the main surfaces 22m, 23m, and an end surface 54 is formed between the front side surface 52 and the rear side surface 53. The front side surface 52, the rear side surface 53, and the end surface 54 can all be perpendicular or approximately perpendicular to the plane on which the fastener tapes 3a, 3b exist. The end surface 54 is located most inward of the fastener elements 4a, 4b. The inward direction of the tape is the direction from a position outside the tape surface of the fastener tapes 3a, 3b to which the fastener elements 4a, 4b are attached toward a position on the tape, and is perpendicular to the side edges of the fastener tapes 3a, 3b.

[0040] The engaging head 21 may have upper and lower main surfaces 21m formed continuously and adjacent to the main surfaces 22m, 23m of the legs 22, 23 in the same plane, a tip surface 46j of the engaging projection 46, a first peripheral surface 46k formed around the tip surface 46j, a bottom surface 47j of the engaging recess 47, and a second peripheral surface 47k formed around the bottom surface 47j. The main surface 21m is a flat surface like the main surfaces 22m, 23m, but is not limited to this. Needless to say, the edges between the surfaces of the fastener elements 4a, 4b may be chamfered.

[0041] In a fastener chain in which the left and right fastener elements 4a, 4b are alternately engaged, the main surface 51 is more susceptible to impact from magnetic media during the electroplating process than the front side surface 52, rear side surface 53, and end surface 54. For example, in one fastener stringer, the front side surface 52 of the rear fastener element and the rear side surface 53 of the front fastener element face each other, defining a narrow liquid space between them. Magnetic media in the plating solution are more likely to move in liquid spaces other than this narrow liquid space. Therefore, a plating layer (particularly the first plating layer described below) can be formed more satisfactorily on the main surface 51 than on the front side surface 52 and rear side surface 53 of the fastener elements 4a, 4b. The same applies to the relationship between the end surface 54 and the main surface 51, although to different degrees. Generally speaking, a plating layer (particularly the first plating layer described below) can be formed non-uniformly on different surfaces of the fastener elements 4a, 4b. The first plating layer between the front side surface 52 and the rear side surface 53 is formed non-uniformly with respect to the first plating layer between the main surface 51 (or main surfaces 22m, 23m) and the tape surface. Non-uniformity means that the thickness of one is outside the range of 0.8 to 1.2 times the thickness of the other. Typically, the first plating layer directly below the main surface 51 is thicker than the first plating layer in other locations, but this is not necessarily the case.

[0042] As described above, the main surfaces 51 of the fastener elements 4a, 4b are more susceptible to impacts from the magnetic media during the electroplating process than the tip surfaces 46j, first circumferential surfaces 46k, and bottom surfaces 47j and 47k of the engaging recesses 47 of the fastener elements 4a, 4b. For example, the first circumferential surface 46k of the rear fastener element and the second circumferential surface 48k of the front fastener element of the two left and right fastener elements 4a, 4b engaged with each other in the left and right fastener stringers 2a, 2b are arranged opposite each other with a small gap. The same applies to the tip surfaces 46j and the bottom surfaces 47j. The magnetic media in the plating solution are more likely to move in places other than the small gap. Therefore, the plating layer (particularly the first plating layer described below) can be formed more effectively on the main surfaces 51 than on the tip surfaces 46j, first circumferential surfaces 46k, bottom surfaces 47j, and second circumferential surfaces 47k of the fastener elements 4a, 4b. Typically, the first plating layer directly below the main surface 51 is thicker than the first plating layer in other locations, but this is not necessarily the case.

[0043] The following description will be made with reference to Figure 4. Figure 4 schematically shows that a plating layer 84 and a metal substrate 83 are formed in this order from the main surface 51 of the fastener elements 4a, 4b toward the inside of the fastener elements 4a, 4b. The plating layer 84 includes first and second plating layers 81, 82 formed in this order on the substrate 83. As described below, the first plating layer 81 and the second plating layer 82 can be distinguished by the difference in the area of ​​the crystal grains observable in a TEM image, but in reality, they are a single plating layer formed by a single or common electroplating process and apparatus. Note that the plating layer described in this specification does not need to be formed in a layered form over the entire main surface 51 (unless this point is specified), and similarly, it does not need to be formed as a flat layer (unless this point is explicitly stated).

[0044] For each leg portion 22, 23, a second plating layer 82, a first plating layer 81, and a metal substrate 83 are formed in this order between the main surface portion 51b of the leg portion 22, 23 and the tape surface of the fastener tape 3a, 3b. No plating layer 84 is formed on the contact surfaces 22t, 23t of the leg portions 22, 23. When the leg portions 22, 23 are cut along a plane parallel to the tape surface, the second plating layer, the first plating layer, the substrate, the first plating layer, and the second plating layer are formed in this order between the front side surface 52 and the rear side surface 53.

[0045] The substrate 83 includes one or more base metal elements. In some cases, the substrate 83 includes copper (Cu) as the base metal element, and in other cases, the substrate 83 includes copper (Cu) and zinc (Zn) as the base metal elements. The former means that the substrate 83 is made of copper, and the latter means that the substrate is made of brass (CuZn). Forms in which the substrate 83 is made of other alternative or additional metal elements are also envisioned. As demonstrated in Patent Document 1, there are many candidates for the metal elements contained in the substrate and plating layer, and the metal elements are not limited to a specific metal element. Note that this specification does not discuss trace amounts of unavoidable metal elements that are inevitably mixed into metals.

[0046] The plating layer 84 includes a first plating layer metal element that is the same metal element as the base metal element, and a second plating layer metal element that is a different metal element from the base metal element. If the base material 83 is made of brass (CuZn), the plating layer 84 includes both copper (Cu) and zinc (Zn) as the first plating layer metal element. If the base material 83 is made of copper (Cu), the plating layer 84 includes copper (Cu) as the first plating layer metal element. The plating layer 84 includes a second plating layer metal element that is a different metal element from the base metal element. For example, when tin (Sn) is used as a soluble anode in the electroplating process, the plating layer 84 includes tin (Sn) as the second plating layer metal element. It is also possible for the plating layer 84 to include multiple different metal elements as the second plating layer metal element.

[0047] The above description of the plating layer 84 also applies to the first plating layer 81 and the second plating layer 82. That is, the first plating layer 81 and the second plating layer 82 each contain a first plating layer metal element that is the same metal element as the base metal element and a second plating layer metal element that is a different metal element from the base metal element. To reiterate, when the base material 83 is made of brass (CuZn), the first plating layer 81 and the second plating layer 82 each contain both copper (Cu) and zinc (Zn) as the first plating layer metal element. When the base material 83 is made of copper (Cu), the first plating layer 81 and the second plating layer 82 each contain copper (Cu) as the first plating layer metal element. When tin (Sn) is used as a soluble anode in the electroplating process, the first plating layer 81 and the second plating layer 82 each contain tin (Sn) as the second plating layer metal element. It is also conceivable that each of the first plating layer 81 and the second plating layer 82 contains a plurality of different metal elements as the second plating layer metal elements.

[0048] In various preferred embodiments, the thickness of the first plating layer 81 is 200 nm or less or 150 nm or less, and / or the thickness of the second plating layer 82 is preferably within the range of 100 to 1000 nm. The first plating layer 81 can be formed thinner than the second plating layer 82 (in other words, the second plating layer 82 can be formed thicker than the first plating layer 81), which is advantageous from the viewpoint of achieving both higher adhesion of the plating layer and a shorter electroplating process time.

[0049] FIG. 5 is a graph showing that in the plating layer 84, the elemental ratio of the metal elements in the first plating layer continuously decreases with increasing distance from the substrate throughout the thickness of the plating layer 84 (the total thickness of the first and second plating layers 81, 82), and the elemental ratio of the metal elements in the second plating layer continuously increases with increasing distance from the substrate throughout the thickness of the plating layer (the total thickness of the first and second plating layers 81, 82). FIG. 5 shows the change in the elemental ratio of the plating layer of a fastener element electroplated on a brass substrate using tin (Sn) as a soluble anode using an electroplating apparatus described below. In FIG. 5, the boundary line L1 between the substrate and the first plating layer is roughly indicated by a dotted line, and the boundary line L2 between the first plating layer and the second plating layer is roughly indicated by a dotted line. In reality, the boundary line between the first plating layer and the substrate is observed in a TEM image as a rough line corresponding to the area difference of the crystal grains (see FIG. 6). The same applies to the boundary line between the first plating layer and the second plating layer.

[0050] The element ratio of the metal elements in the first plating layer (Cu and Zn in the case of FIG. 5) continuously decreases with increasing distance from the substrate, while the element ratio of the metal elements in the second plating layer (Sn in the case of FIG. 5) continuously increases with increasing distance from the substrate. This trend is consistently observed in the thickness of plating layer 84 (the total thickness of first and second plating layers 81, 82).

[0051] As can be seen from Figure 5, in the depth direction from the surface of the plated material toward the substrate, the first plating layer is formed closer to the substrate than the intersection point P1 between the plot line PL1 of the elemental ratio of the first plating layer metal element (Cu in Figure 5) and the plot line PL2 of the elemental ratio of the second plating layer metal element (Sn in Figure 5). More precisely, in the depth direction from the surface of the plated material toward the substrate, the first plating layer is formed closer to the substrate than the intersection point P1 between the plot line PL1 of the elemental ratio of the first plating layer metal element (Cu), which is the same as the base metal element (Cu) with the highest elemental ratio among the base metal elements (Cu, Zn), and the plot line PL2 of the elemental ratio of the second plating layer metal element (Sn). This feature means that the first plating layer is formed thin, which is advantageous from the perspective of achieving both higher adhesion of the plating layer and a shorter electroplating process time.

[0052] 5, the intersection point P2 between the plot line PL3 of the element ratio of the first plating layer metal element (Zn) that is the same as the base metal element (Zn) with the lower element ratio among the base metal elements (Cu, Zn) and the plot line PL2 of the element ratio of the second plating layer metal element (Sn) can be located within the layer thickness of the first plating layer. This characteristic means that the first plating layer can be formed thin, which is advantageous from the viewpoint of achieving both higher adhesion of the plating layer and a shorter electroplating process time.

[0053] In some cases, the distance D1 between the intersection P1 and the first plating layer is 50 nm or more. This characteristic means that the first plating layer 81 is formed thin and also has a low elemental ratio of the second plating layer metal element (Sn) in the first plating layer 81. Unique effects may be obtained depending on the combination of the first plating layer metal element and the second plating layer metal element. As a non-limiting example, when the first plating layer metal element is copper and the second plating layer metal element is tin, the first plating layer contains a speculum alloy with an elemental ratio of tin of less than 40%. Speculum alloys do not discolor in the atmosphere, are hard, and are resistant to rust, and provide the effects of improving corrosion resistance and wear resistance. The distance D1 between the intersection P1 and the first plating layer is typically 100 nm or less.

[0054] The following description will be made with reference to FIGS. 6 and 7. FIG. 6 is a TEM (Transmission Electron Microscope) image (observation magnification: 50,000 times, observation field: 2.5 μm × 1.9 μm) showing a cross section of a plated material (specifically, a fastener element) according to the present disclosure. FIG. 7 is an enlarged image of the portion within the dotted line frame in the TEM image shown in FIG. 6. The second plating layer 82 can be observed as a layer with larger crystal grains than the first plating layer 81, making it distinct from the first plating layer 81. (This characteristic is in contrast to the fact that the change in the element ratio of the metal elements in the first and second plating layers is continuous on both sides of the boundary line L2 between the first plating layer 81 and the second plating layer 82 (see FIG. 5 )). This promotes both higher adhesion of the plating layer and a shorter electroplating process. Additionally or alternatively, the second plating layer 82 can have relatively greater ductility due to its larger crystal grains than the first plating layer 81.

[0055] In the TEM image, an uneven boundary line L1 due to the difference in the area of ​​the crystal grains can be drawn between the substrate 83 and the first plating layer 81, but a flat interface (as observed in normal barrel plating) cannot be observed. An uneven boundary line L2 due to the difference in the area of ​​the crystal grains can also be drawn between the first plating layer 81 and the second plating layer 82, but a flat interface (as observed in normal barrel plating) cannot be observed. For the interface observed in conventional barrel plating, see Figure 8 of Patent Document 1.

[0056] The first plating layer 81 is a layer consisting of a plurality of densely packed first crystal grains, and the second plating layer 82 is a layer consisting of a plurality of densely packed second crystal grains. In Figures 6 and 7, the plurality of first crystal grains each having a width of less than 100 nm and the plurality of second crystal grains each having a width of more than 100 nm can be clearly observed. The difference in width between the first crystal grains and the second crystal grains promotes both higher adhesion of the plating layer and a shorter electroplating process.

[0057] The areas of the first crystal grains and the second crystal grains can be calculated by applying a rectangular frame to a TEM image at a desired magnification. When a rectangular frame is applied to one second crystal grain in a TEM (Transmission Electron Microscope) image at a desired magnification (e.g., the one shown in FIG. 6), half the area of ​​the rectangular frame can be calculated as the area of ​​the second crystal grain. When a rectangular frame is applied to one first crystal grain in a desired TEM image (e.g., the one shown in FIG. 6 or one at a higher magnification), half the area of ​​the rectangular frame can be calculated as the area of ​​the first crystal grain. The areas of a predetermined number of crystal grains, typically 10 or 20, can be calculated using the above method, and the average value of the crystal grain areas can be obtained. The average area of ​​the second crystal grains observed in the TEM image is 10,000 nm 2 or more, or 50,000 nm 2 or more, or 100,000 nm 2 The average area of ​​the primary crystal grains observed in the TEM image can be 1000 nm or more. 2 or less than 2000 nm 2The average area described here is based on the results of calculations performed on several plating material samples in accordance with the above-mentioned method. Note that the first crystal grains and the second crystal grains have different contour shapes observed in TEM images, so the area of ​​each crystal grain is calculated as half the value of the rectangular frame. For a more accurate calculation of the area of ​​the first crystal grains, a TEM image with a higher magnification than the TEM image used to calculate the area of ​​the second crystal grains can also be used.

[0058] Figures 8 and 9 show the actual application of a rectangular frame to a TEM image (50,000x magnification, 2.5 μm × 1.9 μm field of view) for calculating the area of ​​the second crystal grain. In the TEM image, the rectangular frame is set so that a given second crystal grain is inscribed within the four sides of the rectangular frame. To simplify the positioning of the rectangular frame, a small gap may exist between a side of the rectangular frame and the outline of the second crystal grain. This is justified by the use of a correction factor to calculate the area of ​​the second crystal grain, as described below. A rectangular frame on a TEM image includes the entire cross-section of one second crystal grain (i.e., one second crystal grain entirely surrounded by the rectangular frame) and partial cross-sections of one or more other second crystal grains surrounding the second crystal grain. Depending on the position of the second crystal grain to which the rectangular frame is applied, the entire or partial cross-sections of one or more first crystal grains may also be included. Therefore, it is appropriate to multiply the product of the lengths of the first side of the rectangular frame and the second side perpendicular to it by a correction factor. This reduces the influence of noise components contained in the product of the lengths of the first side and the second side perpendicular to the first side of the rectangular frame. The correction coefficient is a number greater than 0 and less than 1, and in this disclosure, 0.5 is used.

[0059] FIG. 10 shows a rectangular frame applied to a TEM image (magnification: 200,000 times, field of view: 0.6 μm × 0.5 μm) for calculating the area of ​​the first crystal grains. FIGS. 11 and 12 show a rectangular frame applied to a TEM image (magnification: 500,000 times, field of view: 0.3 μm × 0.2 μm) for calculating the area of ​​the first crystal grains. The area of ​​the first crystal grains in the TEM image is calculated in the same manner as the method for calculating the area of ​​the second crystal grains in the TEM image described above. Preferably, a TEM image acquired at a higher magnification than the TEM image used for calculating the second crystal grains is used because the first crystal grains are smaller than the second crystal grains. For reference, FIG. 13 shows a rectangular frame applied to the second crystal grains near the surface of the second plating layer, away from the first plating layer.

[0060] The following description will be made with reference to Table 1 and FIG. 14. In Table 1 and FIG. 14, the areas of the crystal grains conform to the method using rectangular frames described above. EM1 in FIG. 14 shows the area distribution of the first crystal grains in the plating layer 84 of the plated material shown in FIGS. 6 and 7. EM2 in FIG. 14 shows the area distribution of the second crystal grains in the plating layer 84 of the plated material shown in FIGS. 6 and 7. EM3 in FIG. 14 shows the area distribution of the crystal grains in the plating layer according to the comparative example of Patent Document 1. EM1 in FIG. 14 shows the plot distribution of the areas of the 20 first crystal grains shown in Table 1. EM2 in FIG. 14 shows the plot distribution of the areas of the 20 second crystal grains shown in Table 1. EM3 in FIG. 14 shows the plot distribution of the areas of the 20 second crystal grains shown in Table 1.

[0061]

[0062] As shown in Table 1, the maximum area of ​​the crystal grains in the area distribution of the first plating layer 81 is 4100 nm 2 The minimum area of ​​the crystal grains in the area distribution of the second plating layer 82 is 40,000 nm 2 Thus, although the first plating layer 81 and the second plating layer 82 are continuous in the thickness direction of the plating layer 84, there is a large difference in the area distribution of the crystal grains in the first plating layer 81 and the second plating layer 82 in terms of the area of ​​the crystal grains (vertical axis in FIG. 8). In some cases, the average area (unit: nm2 ) is the average area of ​​the first crystal grains (unit: nm 2 The area difference between the first crystal grains and the second crystal grains is greater than 10 times (or 50 times) the area difference between the first crystal grains and the second crystal grains. This promotes both higher adhesion of the plating layer and a shorter electroplating process time.

[0063]

[0064] The variances of EM1 to EM3 shown in Table 2 were calculated based on the areas of the crystal grains shown in Table 1. The average value of the crystal grain areas can be calculated based on the formula in Equation 1. The variances can be calculated based on the formula in Equation 2. For convenience of calculation, the variance values ​​are expressed in exponential notation, and the rational numbers are expressed with two digits including the decimal point. The values ​​are rounded to two decimal places. where n is the number of samples and x i indicates the observed value. where n is the number of samples and x i indicates the observed value.

[0065] The variance of the area distribution of the crystal grains in the first plating layer 81 (= 6.2 × 10 5 ) is the variance (=6.7×10) of the area distribution of the crystal grains in the second plating layer 82. 9 ), which satisfies the condition of 1 / 1000 or less (any one condition selected from 1 / 9000 or less, 1 / 8000 or less, 1 / 7000 or less, 1 / 6000 or less, 1 / 5000 or less, 1 / 4000 or less, 1 / 3000 or less, and 1 / 2000 or less may also be satisfied). This means that the crystal grains of the first plating layer 81 are formed more densely than the crystal grains of the second plating layer 82.

[0066] The dispersion ratio shown in the row for EM2 in Table 2 is calculated by dividing the dispersion of EM1 by the dispersion of EM2. The dispersion ratio shown in the row for EM3 in Table 2 is calculated by dividing the dispersion of EM1 by the dispersion of EM2. These dispersion ratio values ​​also show that the crystal grains of the first plating layer 81 are densely formed.

[0067]

[0068] Table 3 shows the results of calculating the standard deviation based on the variances shown in Table 2. The standard deviation for the area of ​​the crystal grains in the first plating layer 81 (=1163) is approximately 1 / 69 of the standard deviation for the area of ​​the crystal grains in the second plating layer 82 (=79897), which satisfies the condition of 1 / 10 or less (any one condition selected from 1 / 60 or less, 1 / 50 or less, 1 / 40 or less, 1 / 30 or less, and 1 / 20 or less may also be satisfied). This means that the crystal grains in the first plating layer 81 are formed more densely than the crystal grains in the second plating layer 82.

[0069] By forming the second plating layer 82 thick, the average area of ​​the second crystal grains may be larger than the average area of ​​the first crystal grains. Similarly, the variance of the area of ​​the second crystal grains may be larger than the variance of the area of ​​the first crystal grains (the same applies to the standard deviation). In this regard, the maximum thickness of the second plating layer may be less than 15 times, less than 10 times, or less than 5 times the maximum thickness of the first plating layer. In the plated materials observed in Table 1 and FIG. 14, the thickness of the first plating layer 81 is in the range of 50 nm to 150 nm, and the thickness of the second plating layer 82 is in the range of 300 nm to 500 nm. The maximum thickness of the second plating layer 82 is less than 5 times the maximum thickness of the first plating layer 81.

[0070] It is not practical to observe and calculate the areas of all first and second crystal grains contained in a given plating material. Therefore, to calculate the average area of ​​crystal grains, as described above, it is advisable to calculate the average area based on a predetermined number of crystal grains (e.g., 18, 20, 30, 40, or 50) randomly selected from a TEM image at a desired magnification. For random selection, the TEM image can be divided into multiple areas, and the same number of crystal grains can be selected in each area. Additionally or alternatively, a rule can be adopted in which crystal grains with an area larger than the area of ​​the crystal grains selected in the first selection are selected in the second selection, and crystal grains with an area smaller than the area of ​​the crystal grains selected in the second selection are selected in the third selection. Increasing the number of samples enables more accurate evaluation.

[0071] The following description will be given with reference to Figures 15 to 17. Figure 15 relates to a case where the second plating layer metal element is tin, while Figures 16 and 17 relate to a case where the second plating layer metal element is copper (the base metal element is a metal element other than copper). From both figures (particularly Figure 16), it can be seen that numerous dents are formed on the surface of the fastener element, and that the surface of the fastener element is matte-finished. By using the plating layer 84 as the outermost layer without forming an additional plating layer on the plating layer 84 of the plated material, the matte pattern obtained simultaneously with the electroplating process (from impact with magnetic media) can be revealed. When the plated material is a fastener element, in addition to the design effect of the matte pattern, an optical effect of reducing the glossiness of the main surface can also be obtained. Note that the dents on the surface of the fastener element are not limited to being matte-finished. As shown in Figure 17, no dents are formed on the bottom surface 47j of the engaging recess 47 of the fastener element. This confirms that the fastener element is electroplated using the electroplating method of the present disclosure while still in the state of a fastener chain, thereby promoting efficient electroplating. The bottom surface 47j of the engaging recess 47 is usually not visible to the user, and the design of the fastener element is not impaired even if no pattern is formed there.

[0072] The electroplating device and process will be described in detail below with reference to Figures 18 to 27. In the description of the electroplating device and process, in principle, the fastener elements 4a', 4b' match the base material 83 of the fastener elements 4a, 4b described above. Therefore, it should be noted that the plating layer will be described as being formed on the fastener element, and not as being included in the fastener element.

[0073] From the viewpoint of high production efficiency required for the slide fastener 1, the fastener elements 4a', 4b' are not electroplated individually, but rather the base material of the fastener elements is electroplated in a state in which the fastener elements 4a', 4b' are attached to the fastener tapes 3a, 3b (for example, in the form of a fastener stringer or fastener chain). In the following description, the electroplating treatment is performed on the fastener chain, but it can also be understood by replacing it with the fastener stringer.

[0074] An exemplary manufacturing method includes the following steps (see, for example, FIGS. 18 and 19 ): applying a voltage between one or more cathodes 10 and one or more anodes 20 at least partially immersed in an electrolyte in a plating bath 30; generating an alternating magnetic field in the electrolyte when or for a period of time that a voltage is applied between the one or more cathodes 10 and the one or more anodes 20; continuously transporting the fastener chain 1′ along a predetermined travel path 80 so that at least the fastener elements 4 a′, 4 b′ of the fastener chain 1′ pass through the alternating magnetic field; and moving a plurality of magnetic media 9 in response to the alternating magnetic field, so that the fastener elements 4 a′, 4 b′ are electrically connected to the cathodes 10 via the plurality of magnetic media 9, and the plurality of magnetic media 9 collide with a plating layer growing on the fastener elements 4 a′, 4 b′.

[0075] The conveying speed of the fastener chain 1' can be 10 m / min or more, or 15 m / min or 20 m / min. By conveying the fastener chain 1' at such a high speed, high productivity can be obtained and also the formation of crystal grains of the second plating layer 82, which are coarser than the crystal grains of the first plating layer 81 shown in Figs. 6 to 8, is promoted.

[0076] The process of generating an alternating magnetic field in the electrolyte can include rotating one or more magnetic rotating parts 60 (see FIG. 20) in which different magnetic poles are arranged alternately in the rotational direction. The magnetic rotating parts 60 are housed in a rotatable, sealed magnetically permeable housing 70 (see FIG. 21). A plurality of support members 78 for supporting the fastener chain 1' are provided on the outer surface of the magnetically permeable housing 70 (see FIG. 18), and a transport path for the fastener chain 1' is defined. By rotating the magnetic rotating parts 60 at high speed within the magnetically permeable housing 70, the magnetic pole closest to a certain fastener element 4a', 4b' continuously alternates between an N pole and an S pole, as shown in FIGS. 19(a) and 19(b). In this way, the magnetic media 9 moves randomly and collides with the fastener elements 4a', 4b' traveling along the transport path and with the plating layer growing thereon.

[0077] 18, the electroplating apparatus 100 includes a plating tank 30, a conveying mechanism 40, an alternating magnetic field generating unit 50, and a running path 80 for a fastener chain 1'. The fastener chain 1' enters the plating tank 30 from outside via rollers 41 and 42 of the conveying mechanism 40, and exits the plating tank 30 from inside via rollers 43 and 44 of the conveying mechanism 40.

[0078] The plating tank 30 stores an electrolyte 35 in which one or more cathodes 10 and one or more anodes 20 are immersed. The plating tank 30 is an insulating container having a bottom plate 31 and side plates 32. The electrolyte 35 in the plating tank 30 is, for example, a cyanide-based plating solution, which is circulated between the plating tank 30 and an external sub-tank. From the perspective of reducing environmental impact, it is preferable to use a plating solution that does not contain specific hazardous substances such as cyanide, chromium, or selenium. The cathode 10 and the anode 20 are connected to a DC power source E1, and a voltage is applied between them. The voltage application state can be controlled by turning a switch SW on and off. The anode 20 may be a soluble or insoluble anode. The metal element of the anode 20 is appropriately determined depending on the metal element of the second plating layer. The cathode 10 is located away from the anode 20 in the electrolyte 35 to supply electrons to the fastener elements 4a', 4b' (to set the fastener elements 4a', 4b' to a cathode potential).

[0079] The alternating magnetic field generating unit 50 generates an alternating magnetic field in the electrolyte 35 of the plating bath 30. An alternating magnetic field is a magnetic field whose magnitude and direction change over time. The running path 80 of the fastener chain 1' is provided so that the fastener chain 1' is placed in the alternating magnetic field generated by the alternating magnetic field generating unit 50. When the generation of the alternating magnetic field and the running of the fastener chain 1' are performed simultaneously or during the same period, the fastener elements 4a', 4b' of the fastener chain 1' pass through the alternating magnetic field generated by the alternating magnetic field generating unit 50.

[0080] The cathode 10 allows a plurality of magnetic media to move (for example, rotate) in accordance with the above-mentioned alternating magnetic field between the fastener elements 4a', 4b' of the fastener chain 1' supported by the support member 78 and the cathode 10, and is provided so as to be electrically connectable to the fastener elements 4a', 4b' via the plurality of magnetic media. In other words, (i) a space in which a plurality of magnetic media move in accordance with the alternating magnetic field is provided between the fastener elements 4a', 4b' of the fastener chain 1' supported by the support member 78 and the cathode 10, and (ii) this space is set so that the fastener elements 4a', 4b' are electrically connected to the cathode 10 via the plurality of magnetic media, and the plurality of magnetic media can collide with the plating layers growing on the fastener elements 4a', 4b'.

[0081] The above-described configuration ensures that both the growth of the plating layer on the fastener elements 4a', 4b' and the collision of the magnetic media with the plating layer occur simultaneously. This promotes the formation of a plating layer of sufficient quality (e.g., processing resistance). Furthermore, when the fastener chain is run continuously or intermittently in the running path 80 defined by the support member 78, the electroplating process can be performed efficiently.

[0082] The support member 78 can be provided to control the position and orientation of the fastener chain 1' so that the longitudinal direction of the fastener chain 1' is along a predetermined direction (for example, the circumferential direction and / or rotation direction of the magnetic rotating part 60 described later) in which different magnetic poles are alternately arranged to generate an alternating magnetic field, and so that the fastener chain 1' faces the magnetic poles in a flat attitude in its width direction. This promotes the formation of a plating layer with uniform quality and / or thickness.

[0083] The alternating magnetic field generating unit 50 includes a motor 61 and a magnetic rotating unit 60 rotated by the motor 61. The motor 61 is, for example, a DC or AC motor. In the magnetic rotating unit 60, different magnetic poles (i.e., north and south poles) are arranged alternately in the direction of rotation. The magnetic poles can be permanent magnets, electromagnets, or a combination of these. In the case shown in FIG. 20, permanent magnets are used for the magnetic poles. The magnetic rotating unit 60 includes a rotating body 63 rotatably fixed to a rotating shaft 62 of the motor 61 and multiple permanent magnets 64 attached to the outer surface of the rotating body 63. The rotating body 63 is, for example, a hollow cylindrical member made of stainless steel. The permanent magnets 64 can be rare-earth magnets such as neodymium magnets, but other types can also be used. It is not necessary to provide one motor 61 for each magnetic rotating unit 60. The output of the motor 61 can also be supplied to multiple magnetic rotating units 60 via an appropriate power transmission system. The rotating shaft 62 of the motor 61 can be fixed to an opening in the bottom plate 31 of the plating tank 30 via a waterproof bearing.

[0084] The multiple permanent magnets 64 are arranged so that the south and north poles are alternately aligned in the direction of rotation of the magnetic rotating unit 60 (see FIG. 20). When the magnetic rotating unit 60 rotates in response to the operation of the motor 61, the magnetic rotating unit 60 alternates between the south and north poles as viewed from a predetermined position radially outward of the magnetic rotating unit 60. Magnetic media (e.g., pin media) located at a predetermined position radially outward of the magnetic rotating unit 60 rotates in response to the change in magnetic pole (closest to the magnetic media) and flows in the direction of rotation of the magnetic rotating unit 60. The rotation speed of the magnetic rotating unit 60 is, for example, 100 to 4,000 rpm.

[0085] 20 , N-pole-arranged zones Z1, Z3, and Z5, in which permanent magnets 64 with their N poles facing outward, and S-pole-arranged zones Z2 and Z4, in which permanent magnets 64 with their S poles facing outward, may be alternately provided on the outer surface of the magnetic rotating unit 60 in the direction of rotation of the magnetic rotating unit 60. In FIG. 20 , the N-pole-arranged zones Z1, Z3, and Z5 and the S-pole-arranged zones Z2 and Z4 extend vertically in a straight line parallel to the rotation axis of the magnetic rotating unit 60, but this is not limited to this. In some cases, taking into account the sedimentation of magnetic media due to gravity, the N-pole-arranged zones Z1, Z3, and Z5 and the S-pole-arranged zones Z2 and Z4 may extend diagonally vertically non-parallel to the rotation axis of the magnetic rotating unit 60, or may extend vertically in a zigzag pattern non-parallel to the rotation axis of the magnetic rotating unit 60.

[0086] The electroplating apparatus 100 further includes a magnetically permeable housing 70, which rotatably and hermetically houses the magnetic rotating unit 60. The magnetically permeable housing 70 transmits magnetic flux from the north pole to the south pole of the permanent magnet 64 of the magnetic rotating unit 60 therein, thereby forming a magnetic field outside the magnetically permeable housing 70. The magnetically permeable housing 70 does not rotate together with the magnetic rotating unit 60 upon operation of the motor 61 but remains stationary in a predetermined position. For example, the magnetically permeable housing 70 is coupled to the rotating shaft 62 (at its bottom and top plates) via a waterproof bearing. The provision of the magnetically permeable housing 70 can protect the magnetic rotating unit 60 from the electrolyte 35 and / or reduce the rotational resistance of the magnetic rotating unit 60. The magnetically permeable housing 70 is made of a resin, such as polypropylene, acrylic, or vinyl chloride.

[0087] A plurality of support members 78 are provided on the outer surface of the magnetically permeable housing 70 as one or more supports for supporting the fastener chain 1'. This controls the position and posture of the fastener chain 1' and defines its running path 80. Preferably, the supports (e.g., the support members 78) support the fastener chain 1' in a flat posture. The fastener chain 1' can run circumferentially around the magnetic rotating part 60, specifically, at a position radially outward from the rotation axis 62 of the magnetic rotating part 60. Although the magnetic flux density decreases with increasing distance radially outward from the magnetic rotating part 60, providing the support members 78 on the magnetically permeable housing 70 allows the fastener chain 1' to run near the magnetic rotating part 60. The magnetic media can move significantly between the magnetically permeable housing 70 and the fastener chain 1' in response to the alternating magnetic field, allowing the magnetic media to strongly collide with the plating layer. In some cases, a plurality of support members 78 are attached to the outer surface of the magnetically permeable housing 70 to define the spiral running path 80 of the fastener chain 1'. By forming the traveling path 80 in a spiral shape, it is possible to prevent the electroplating apparatus 100 from becoming large.

[0088] Each support member 78 is an L-shaped member, and specifically has a first rod portion 78a extending radially outward from the rotation axis 62 of the magnetic rotating portion 60, and a second rod portion 78b extending upward at a predetermined interval from the outer surface of the magnetic permeable housing 70. The first rod portion 78a prevents the fastener chain 1' from sinking in the electrolyte 35 due to gravity. The second rod portion 78b prevents the fastener chain 1' from falling away from the outer surface of the magnetic permeable housing 70 due to gravity, magnetic media, water flow, or the like. The support member 78 can be fixed to the outer periphery of the magnetic permeable housing 70 by any method, such as screwing or adhesive.

[0089] The cathode 10 can be provided on the outer surface of the magnetically permeable housing 70. The cathode 10 is provided so as to extend along the running path of the fastener chain 1'. This is expected to result in good electrical connection of the fastener elements 4a', 4b' to the cathode 10 via the magnetic media. In some cases, the cathode 10 is provided spirally around the magnetically permeable housing 70 in correspondence with the spiral running path 80 of the fastener chain 1'. Additionally or alternatively, the cathode 10 is provided at a position where the fastener elements 4a', 4b' of the fastener chain 1' running along the running path 80 face the cathode 10. Note that the permanent magnet 64, the magnetically permeable housing 70, the cathode 10, the magnetic media, and the fastener elements 4a', 4b' are arranged coaxially in the radial direction relative to the rotation axis of the magnetic rotating part 60.

[0090] When the cathode 10 is provided on the outer surface of the magnetically permeable housing 70, an induced electromotive force is generated in the cathode 10 due to the rotation of the magnetic rotating part 60, and an induced current flows in the cathode 10. To reduce this effect, the cathode 10 is provided in a linear shape (rather than a cylindrical shape) on the outer surface of the magnetically permeable housing 70. This reduces the magnetic flux linking to the cathode 10, and the induced electromotive force and induced current can be suppressed. Note that a spiral-shaped cathode 10 can be constructed by winding a linear cathode 10 in a spiral shape around the outer surface of the magnetically permeable housing 70. The linear cathode 10 can also be provided on the outer surface of the magnetically permeable housing 70 in a manner other than a spiral shape. The cathode 10 can be fixed to the outer surface of the magnetically permeable housing 70 by a method such as screws, adhesive, or fitting.

[0091] If the cathode 10 is provided in a linear or spiral shape, the length of the cathode 10 will be long. In order to stabilize the cathode potential, multiple contacts with the DC power source E1 can be provided on the cathode 10 in one magnetically permeable housing 70, or the cathode 10 can be divided and each contact with the DC power source E1 can be provided individually.

[0092] A frame 72 can be used to arrange the anode 20 near the running path 80 of the fastener chain 1' (see FIG. 22). By attaching a plurality of anodes 20 to the frame 72 directly or indirectly via a cage or the like, the plurality of anodes 20 can be arranged at different positions along the running path 80 of the fastener chain 1'. This makes it possible to reduce unevenness in the metal ion concentration along the running path 80 of the fastener chain 1'. For example, a mesh cage is attached to the frame 72, and a metal plate (which functions as the anode 20) is placed inside the cage.

[0093] The frame 72 is positioned radially outward of the magnetically permeable housing 70 with respect to the rotation axis 62 of the magnetic rotating part 60. The frame 72 is a cylindrical mesh member having horizontal members 73 spaced apart in the vertical direction and vertical members 74 connecting the horizontal members 73 to each other in the vertical direction. The frame 72 is constructed so as not to interfere with the running path 80 of the fastener chain 1'. Metal ions eluted from the anode 20 can reach the fastener elements 4a', 4b' of the fastener chain 1' present in the running path 80 through the mesh of the frame 72. As will be apparent to those skilled in the art, the anode 20 can also be disposed near the running path 80 of the fastener chain 1' without using the frame 72.

[0094] The role of the magnetic media will be further explained with reference to Figure 19. In Figure 19(a), the N-pole arrangement zone of the magnetic rotating part 60 is located inside a predetermined position on the outer periphery of the magnetically permeable housing 70. In Figure 19(b), the S-pole arrangement zone of the magnetic rotating part 60 is located inside a predetermined position on the outer periphery of the magnetically permeable housing 70. In both states of Figure 19(a) and Figure 19(b), an appropriate amount of magnetic media 9 exists between the cathode 10 and fastener elements 4a', 4b', where magnetic flux is indicated by dashed lines.

[0095] 19(a) to 19(b), each magnetic media 9 rotates and displaces. Regardless of the change in orientation and displacement of each magnetic media 9, the fastener elements 4a', 4b' can be electrically connected to the cathode 10 via multiple media before, during, or after the change or the entire process. Some magnetic media 9 collide with the plating layer growing on the fastener elements 4a', 4b' when they rotate. In the fastener chain 1', the fastener elements 4a', 4b' can be electrically connected to the cathode 10 via other fastener elements 4a', 4b' even if they are not electrically connected to the cathode 10 via the magnetic media 9.

[0096] Although not necessarily limited to this, the magnetic media 9 can be used to assist the transport of the fastener chain 1'. For example, the rotation direction of the magnetic rotating part 60 and the running direction of the fastener chain 1' running around it are set to be the same direction. In addition to rotating in response to the alternating magnetic field, the magnetic media 9 are entrained by the permanent magnets 64 of the magnetic rotating part 60 and flow in the same direction as the magnetic rotating part 60. The flow of the magnetic media 9 pushes the fastener chain 1', making it easier for the fastener chain 1' to run in the same direction.

[0097] The fastener elements 4a', 4b' of the fastener chain 1' have a first surface 5 facing the cathode 10 and a second surface 6 facing the opposite side of the cathode 10 (see FIG. 19). If the anode 20 is disposed radially outward from the magnetically permeable housing 70 relative to the fastener chain 1' and equivalent magnetic media are present on the first surface 5 side and the second surface 6 side of the fastener elements 4a', 4b', the growth rate of the plating layer on the second surface 6 side of the fastener elements 4a', 4b' will be greater than the growth rate of the plating layer on the first surface 5 side of the fastener elements 4a', 4b'. In order to prevent a difference in thickness of the plating layer on the front and back of the fastener elements 4a', 4b', it is advisable to invert the front and back of the fastener chain 1' in the running path of the fastener chain 1'.

[0098] In the case shown in Figure 18, two alternating magnetic field generating units 50 are provided in the plating tank 30, an upstream spiral running path is provided on the outer periphery of the magnetically permeable housing 70 of the upstream alternating magnetic field generating unit 50, a downstream spiral running path is provided on the outer periphery of the magnetically permeable housing 70 of the downstream alternating magnetic field generating unit 50, and a front / back reversal portion 90 of the fastener chain 1' is provided between these spiral running paths.

[0099] In the case shown in Figure 23, the front / back reversing section 90 has only two guide rollers 91, 92. The front / back reversal of the fastener chain 1' is achieved by reversing the running direction of the fastener chain 1' between the upstream magnetically permeable housing 70 and the downstream magnetically permeable housing 70. That is, as shown in Figure 23, when viewing the plating tank 30 from above, the fastener chain 1' runs clockwise on the upstream spiral running path and runs counterclockwise on the downstream spiral running path. In this way, the front / back of the fastener chain 1' is reversed, which promotes uniformity of the thickness of the plating layer on the front and back of the fastener elements 4a', 4b'. Note that the front / back reversal of the fastener chain 1' can be performed by various other methods.

[0100] The operation of the electroplating apparatus 100 will be described, focusing on a predetermined portion of the fastener chain 1'. First, as the fastener chain 1' is transported, the predetermined portion of the fastener chain 1' is guided by rollers 41 and 42 and reaches a running path 80 in the electrolyte 35. Before the predetermined portion of the fastener chain 1' runs along the running path 80, the magnetic rotating part 60 rotates based on the operation of the motor 61, and an alternating magnetic field is generated around it. The running path 80 of the fastener chain 1' is disposed in an alternating magnetic field, in which the magnetic media 9 move. In addition, a voltage is applied between the cathode 10 and the anode 20 by a DC power supply E1.

[0101] When a predetermined portion of the fastener chain 1' travels along the travel path 80, the fastener elements 4a', 4b' are electrically connected to the cathode 10 provided on the outer surface of the magnetically permeable housing 70 via the magnetic media 9. In addition, the magnetic media 9 repeatedly collide with the plating layer formed on the fastener elements 4a', 4b'. During the period when the predetermined portion of the fastener chain 1' travels from the lower end to the upper end of the spiral travel path 80, growth of the plating layer and collision of the magnetic media 9 with the plating layer occur continuously. In this way, the formation of a plating layer of sufficient thickness is promoted while avoiding an increase in the size of the electroplating apparatus 100.

[0102] The predetermined portion of the fastener chain 1' is then turned over and travels along the next spiral traveling path 80 in the opposite direction, that is, from its upper end to its lower end. During this traveling period, as described above, the growth of the plating layer and the collision of the magnetic media 9 with the plating layer occur continuously. In this way, plating layers are formed on the front and back surfaces of the fastener elements 4a', 4b' of the fastener chain 1'. After traveling along the spiral traveling path 80, the predetermined portion of the fastener chain 1' is guided by the rollers 43, 44 and exits the electrolyte 35.

[0103] Furthermore, metal ions are also deposited at the contact portions between the fastener elements 4a', 4b', forming a plating layer. During electroplating, the engaging rows of the fastener elements 4a', 4b' are continuously electrically connected to the cathode 10 via the magnetic media 9 along the longitudinal direction of the fastener chain 1', and therefore, the occurrence of a potential gradient in the engaging rows of the fastener elements 4a', 4b' along the longitudinal direction of the fastener chain 1' is suppressed. A sequencer can be used to control the on / off of each motor 61 and the on / off of the switch SW. The sequencer can also control the start and stop of transport of the fastener chain.

[0104] In the above description, mainly with reference to Fig. 18, a configuration in which two alternating magnetic field generating units 50, two spiral running paths, and one front / back reversing unit 90 are provided has been described, but a configuration in which only one alternating magnetic field generating unit 50 and one spiral running path are provided is also envisioned. The running path 80 of the fastener chain 1' is not necessarily limited to a spiral shape, and may be linear, zigzag, or the like. In addition, the fastener chain 1' may be wound around a plurality of magnetically permeable housings 70 in a serpentine shape, and this may be repeated along the rotation axis of the magnetic rotating unit 60.

[0105] Variations will be described below with reference to Figs. 24 to 27. Figs. 24 and 25 show a configuration in which four alternating magnetic field generating units 50, four spiral running paths, and two front / back reversing units 90 are provided. In Fig. 24, the fastener chain 1' runs clockwise upward along the first spiral running path, counterclockwise downward along the second spiral running path, counterclockwise upward along the third spiral running path, and clockwise downward along the fourth spiral running path. In Fig. 25, the fastener chain 1' runs counterclockwise upward along the first spiral running path, clockwise downward along the second spiral running path, clockwise upward along the third spiral running path, and counterclockwise downward along the fourth spiral running path. By providing four or more alternating magnetic field generating units 50 and four spiral running paths, it is possible to ensure a sufficient thickness of the plating layer even if the running speed of the fastener chain 1' is increased.

[0106] 26 and 27 show a configuration in which the posture of the fastener chain 1' is maintained by the rollers 41 and 42 of the conveying mechanism 40 instead of the support member 78 (that is, the rollers 41 and 42 of the conveying mechanism 40 function as supports for the fastener chain 1'). In such a case, the same effects as those described above can be obtained within a consistent range.

[0107] The plated materials shown in Figures 6 to 8 were obtained using an electroplating apparatus having the same configuration as that shown in Figure 24. However, various modifications to the electroplating apparatus as described above are possible, and therefore it should be understood that there is no limitation on the configuration of the electroplating apparatus.

[0108] Example: A plating layer was formed on the fastener elements of a fastener chain using the plating apparatus shown in Figure 24 of the present application. The rotation speed of the magnetic rotating part was 400 rpm. The running speed of the fastener chain was 5 m / min. The power supply voltage was 1 V, and a current of 10 A was passed through each cathode. The electroplating time for one fastener element was 15 minutes. 9 g of media was added per 1 L of electrolyte. The media was pin media with a length of 5 mm and a diameter of 0.8 mm. The base material of the fastener element was brass, and a tin bar was used as the soluble anode. As a result, a first plating layer with a layer thickness of 50 nm to 150 nm was formed, and a second plating layer with a layer thickness of 300 nm to 500 nm was formed. A matte pattern was formed on the outermost surface of the second plating layer due to the collision of the magnetic media. The TEM image is as shown in Figure 6.

[0109] In light of the above teachings, those skilled in the art can make various modifications to each embodiment and each feature. The reference numerals included in the claims are for reference purposes only and should not be used to limit the interpretation of the claims.

[0110] 2a: Fastener stringer 2b: Fastener stringer 3a: Fastener tape 3b: Fastener tape 4a: Fastener element 4b: Fastener element 81: First plating layer 82: Second plating layer 83: Base material 84: Plating layer

Claims

1. A plating product comprising a substrate (83) containing at least one substrate metal element, and a plating layer (84) formed on the substrate (83), The plating layer (84) includes first and second plating layers (81, 82) formed in this order on the base material (83), and each of the first and second plating layers (81, 82) includes at least a first plating layer metal element that is the same metal element as the base metal element, and a second plating layer metal element that is a metal element different from the base metal element, the element ratio of the metal element of the first plating layer continuously decreases with increasing distance from the substrate (83) over at least the total thickness of the first and second plating layers (81, 82), and the element ratio of the metal element of the second plating layer continuously increases with increasing distance from the substrate (83) over at least the total thickness of the first and second plating layers (81, 82); The second plating layer (82) can be observed as a layer having larger crystal grains than the crystal grains of the first plating layer (81) in a first TEM (Transmission Electron Microscope) image, distinguishing it from the first plating layer (81).

2. 2. The plating material according to claim 1, wherein the first plating layer (81) is a layer consisting of a plurality of first crystal grains densely packed, the second plating layer (82) is a layer consisting of a plurality of second crystal grains densely packed, each of the plurality of first crystal grains having a width less than 100 nm, and each of the plurality of second crystal grains having a width greater than 100 nm.

3. When a rectangular frame is applied to the second crystal grains in the first TEM image, half the area of ​​the rectangular frame is determined as the area of ​​the second crystal grains. The average area of ​​the second crystal grains in the first TEM image is 10,000 nm 2 Above, 50000nm 2 or more, or 100,000 nm 2 The plating material according to claim 2 .

4. When a rectangular frame is applied to the first crystal grains in the first TEM image or a second TEM (Transmission Electron Microscope) image having a higher magnification, the area of ​​the first crystal grains is determined to be half the area of ​​the rectangular frame. The average area of ​​the first crystal grains in the second TEM image is 2000 nm 2 or less than 1000 nm 2 The plating material according to claim 3, wherein:

5. The average area of ​​the second crystal grains in the first TEM image is greater than 5 or 10 times the average area of ​​the first crystal grains in the second TEM image, and the average areas of the first and second crystal grains are expressed in the same unit nm 2 The plating material according to claim 4, wherein the plating material is represented by the formula:

6. 5. The plating material according to claim 4, wherein a variance of the area of ​​the first crystal grains in the second TEM image is 1 / 1000 or less of a variance of the area of ​​the second crystal grains in the first TEM image, and / or a standard deviation of the area of ​​the first crystal grains in the second TEM image is 1 / 10 or less of a standard deviation of the area of ​​the second crystal grains in the first TEM image.

7. 7. The plating material according to claim 1, wherein a flat interface is not observed between the first plating layer (81) and the second plating layer (82) in the first TEM image, and / or a flat interface is not observed between the substrate (83) and the first plating layer (81) in the first TEM image.

8. The plated product according to claim 1 , wherein a thickness of the first plating layer (81) is smaller than a thickness of the second plating layer (82).

9. The plated material according to claim 1 , wherein the first plating layer (81) has a thickness of 200 nm or less or 150 nm or less.

10. The plated material according to any one of claims 1 to 6, wherein the second plating layer (82) has a thickness in the range of 100 to 1000 nm.

11. 7. The plating material according to claim 1, wherein, in a depth direction from a surface of the plating material toward the substrate (83), the first plating layer (81) is formed on the substrate (83) side of an intersection (P1) between a plot line (PL1) of the element ratio of the first plating layer metal elements and a plot line (PL2) of the element ratio of the second plating layer metal elements.

12. The plating material according to claim 11, wherein the distance between the intersection (P1) and the first plating layer (81) is 50 nm or more.

13. The plating material according to any one of claims 1 to 6, wherein the first plating layer metal element is copper, the second plating layer metal element is tin, and the first plating layer (81) includes a speculum alloy.

14. The plated product according to claim 1 , wherein the surface of the second plating layer (82) has a large number of dents.

15. The plating material according to any one of claims 1 to 6, wherein the plating material is a fastener element (4a, 4b) attached to a fastener tape (3a, 3b), the fastener element (4a, 4b) has at least a pair of legs (22, 23) and an engaging head (21) to which the pair of legs (22, 23) are connected, and the first plating layer (81) is formed non-uniformly on different surfaces of the fastener element (4a, 4b).

16. The plating material according to any one of claims 1 to 6, wherein the plating material is a fastener element (4a, 4b) attached to a fastener tape (3a, 3b), and the fastener element (4a, 4b) includes a surface that is at least partially matte-finished.

17. A fastener stringer (2a, 2b) comprising a fastener tape (3a, 3b) and a plurality of fastener elements (4a, 4b) attached at a predetermined pitch to side edges of the fastener tape (3a, 3b), Each fastener element of the plurality of fastener elements (4a, 4b) comprises a base material (83) containing at least one base metal element, and a plating layer (84) formed on the base material (83), The plating layer (84) includes first and second plating layers (81, 82) formed in this order on the base material (83), and each of the first and second plating layers (81, 82) includes at least a first plating layer metal element that is the same metal element as the base metal element, and a second plating layer metal element that is a metal element different from the base metal element, the element ratio of the metal element of the first plating layer continuously decreases with increasing distance from the substrate (83) over at least the total thickness of the first and second plating layers (81, 82), and the element ratio of the metal element of the second plating layer continuously increases with increasing distance from the substrate (83) over at least the total thickness of the first and second plating layers (81, 82); The second plating layer (82) can be observed as a layer having larger crystal grains than the crystal grains of the first plating layer (81) in a TEM (Transmission Electron Microscope) image, distinguished from the first plating layer (81).

18. The fastener stringer according to claim 17, wherein the fastener element (4a, 4b) has a main surface (51) oriented along a tape surface that defines a thickness of the fastener tape (3a, 3b), and the second plating layer (82), the first plating layer (81), and the base material (83) are formed in this order from the main surface (51) toward the fastener tape (3a, 3b).

19. The fastener elements (4a, 4b) include a pair of legs (22, 23) that sandwich the fastener tapes (3a, 3b), 19. The fastener stringer of claim 18, wherein each leg of the pair of legs (22, 23) includes a front side (52) connected to a front edge of the main surface (51) and a rear side (53) connected to a rear edge of the main surface (51), and the second plating layer (82), the first plating layer (81), the base material (83), the first plating layer (81), and the second plating layer (82) are formed in this order between the front side (52) and the rear side (53).