Plating materials and fastener stringers

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

[Technical Field]

[0001] This disclosure relates to plating materials and fastener stringers. [Background technology]

[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. As shown in Figure 4 of the same document, the elemental ratio of the substrate metal elements (Cu,Zn) decreases continuously as the distance from the substrate increases, and the elemental ratio of the plating layer metal elements (Sn) increases continuously as the distance from the substrate increases. 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.

[0003] Patent Document 2 discloses a method of electroplating by placing a substrate such as a button into a plating tank. In particular, it discloses a method of using a permanent magnet to make a magnetic medium flow together with the substrate such as a button, and performing electroplating while the magnetic medium collides with the substrate such as a button. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2018 / 190202 [Patent Document 2] International Publication No. 2018 / 189916 [Overview of the project] [Problems that the invention aims to solve]

[0005] The plating layer disclosed in Patent Document 1 has higher adhesion to the substrate compared to 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 partly due to the plating layer being struck and having its growth suppressed when it collides with the magnetic media and / or other plating materials during the electroplating process (this does not exclude other additional or alternative factors).

[0006] It is conceivable that the plating layer disclosed in Patent Document 1 be formed as a thin layer, followed by an additional conventional electroplating process without using a magnetic medium. However, in this case, since different electroplating processes must be performed consecutively, it is inherently difficult to shorten the time required for the electroplating process.

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

[0008] A plating material according to one aspect 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 a first and a second plating layer formed on the substrate in this order. Each of the first and second plating layers contains at least a first plating layer metal element which is the same metal element as the base metal element, and a second plating layer metal element which is a different metal element from the base metal element. The elemental ratio of the first plating layer metal element decreases continuously with increasing distance from the substrate over at least the combined thickness of the first and second plating layers, and the elemental ratio of the second plating layer metal element increases continuously with increasing distance from the substrate over at least the combined thickness of the first and second plating layers. The second plating layer can be distinguished from the first plating layer in a first TEM (Transmission Electron Microscope) image as a layer with larger crystal grains compared to the crystal grains of the first plating layer.

[0009] A fastener stringer according to another aspect of the present disclosure includes a fastener tape and a plurality of fastener elements attached to the side edges of the fastener tape at a predetermined pitch. Each 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 on the substrate in this order. Each of the first and second plating layers includes at least a first plating layer metal element which is the same metal element as the base metal element and a second plating layer metal element which is a different metal element from the base metal element. The element ratio of the first plating layer metal element decreases continuously with increasing distance from the substrate over at least the total thickness of the first and second plating layers, and the element ratio of the second plating layer metal element increases continuously 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 as a layer with larger crystal grains compared to the first plating layer in a TEM (Transmission Electron Microscope) image.

[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, where each of the plurality of first crystal grains has a width of less than 100 nm, and each of the plurality of second crystal grains has a width of more than 100 nm.

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

[0012] In some embodiments, when determining the area of the first crystal grain as half of the area of the rectangular frame applied to the first crystal grain in the first TEM image or the second TEM (Transmission Electron Microscope) image with a magnification higher than that, the average area of the first crystal grain in the second TEM image is 2000 nm 2 or less, or 1000 nm 2 or less.

[0013] In some embodiments, the average area of the second crystal grain in the first TEM image is larger than 5 times or 10 times the average area of the first crystal grain in the second TEM image, and the average areas of the first and second crystal grains are represented in the same unit of nm 2 as described.

[0014] In some embodiments, the dispersion of the area of the first crystal grain 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 dispersion of the area of the second crystal grain in the first TEM image, and / or the standard deviation of the area of the first crystal grain 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 grain in the first TEM image.

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

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

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

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

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

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

[0021] In some embodiments, there are a number of indentations on the surface of the second plating layer.

[0022] In some embodiments, the plating material is a fastener element attached to a fastener tape. The fastener element has at least a pair of legs and a head to which the pair of legs are joined. 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 a fastener tape, and the fastener element includes a surface that is at least partially satin-finished.

[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 base material 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 sandwiching the fastener tape. Each leg of the pair of legs includes a front side surface connected to the leading edge of the main surface and a rear side surface connected to the trailing edge of the main surface. Between the front side surface and the rear side surface, the second plating layer, the first plating layer, the base material, the first plating layer, and the second plating layer are formed in this order. [Effects of the Invention]

[0026] According to one aspect of this disclosure, further improvements can be provided for a plating layer in which the elemental ratios of the base metal element and the plating layer metal element change continuously. [Brief explanation of the drawing]

[0027] [Figure 1] This is a schematic diagram of a slide fastener in which a plated material according to one aspect of the present disclosure is embodied as each fastener element. [Figure 2] This is a partially enlarged schematic diagram of Figure 1 showing the left and right fastener elements engaged in an alternating manner. It also schematically shows the state in which the engaging projection of the rear fastener element engages with the engaging recess of the front fastener element. [Figure 3] This is a schematic perspective view of a single fastener element. [Figure 4] This is a schematic diagram of a partial cross-section of a fastener element. [Figure 5] This is a schematic graph showing the change in the ratio of each element in the depth direction from the surface to the interior of a plated material according to one aspect of this disclosure. [Figure 6] Figure 5 shows a TEM (Transmission Electron Microscope) image of the same plated material cross-section (magnification 50,000x, field of view 2.5 μm × 1.9 μm), with a dotted boundary line added between the substrate and the first plating layer, and also between the first and second plating layers. Furthermore, a dotted frame has been added to the enlarged portion of the enlarged image in Figure 7. [Figure 7] This is a magnified image of the area within the dotted line frame in the TEM image shown in Figure 6. [Figure 8] This is a TEM image with a rectangular frame actually applied to calculate the area of ​​the second crystal grain. [Figure 9] This is a TEM image with a rectangular frame actually applied to calculate the area of ​​the second crystal grain. [Figure 10] This is a TEM image with a rectangular frame actually applied to calculate the area of ​​the first crystal grain. [Figure 11] This is a TEM image with a rectangular frame actually applied to calculate the area of ​​the first crystal grain. [Figure 12] This is a TEM image with a rectangular frame actually applied to calculate the area of ​​the first crystal grain. [Figure 13] This is a TEM image in which a rectangular frame has been applied to the second crystal grain near the surface of the second plating layer, which is separated from the first plating layer. [Figure 14] Figures 5 and 6 are graphs showing the distribution of crystal grains of the same plated material. [Figure 15] This is an image showing the surface condition of a plated material according to one aspect of this disclosure. [Figure 16] This is an image showing the surface condition of a plated material according to one aspect of this disclosure. [Figure 17] This is an image showing the bottom surface of an engagement recess in a plated material according to one aspect of the present disclosure. [Figure 18] This is a schematic diagram of an electroplating apparatus according to one aspect of the present disclosure. [Figure 19] This is a schematic diagram illustrating how a magnetic medium moves in response to an alternating magnetic field. [Figure 20] This is a schematic diagram of the magnetic rotating part. [Figure 21] This is a schematic diagram showing how the magnetic rotating part is housed within the magnetic permeable housing. [Figure 22] This is a schematic diagram showing a frame for anode placement. [Figure 23] This is a schematic diagram of the part that reverses the front and back of the zipper chain. [Figure 24] This is a schematic diagram showing a modified example of an electroplating apparatus. [Figure 25] This is a schematic diagram showing another modified example of an electroplating apparatus. [Figure 26] This is a schematic diagram showing yet another modified example of an electroplating apparatus. [Figure 27] This is a schematic diagram showing yet another modified example of an electroplating apparatus. [Modes for carrying out the invention]

[0028] Various embodiments and features will be described below with reference to the drawings. Those skilled in the art will understand that each embodiment and / or feature can be combined without needing excessive explanation, and that the synergistic effects of such combinations will also be understandable. Duplication of explanation between embodiments will be omitted in principle. The reference drawings are primarily for describing the invention and have been simplified for ease of drawing. Each feature is not only effective for the fastener element disclosed in this application as an example of an unspecified plating material, but is understood to be a universal feature applicable to various other metal parts not disclosed herein.

[0029] The plating material and its characteristics described herein will be explained below in relation to the metal fastener elements 4a and 4b included in the slide fastener 1 shown in Figure 1, but will not be limited to this. The plating material can be materialized as various metal parts for clothing, such as a metal slider 7 included in the slide fastener 1, or a metal button unrelated to the slide fastener, or it can be materialized as metal parts in other fields, such as fasteners such as screws and bolts.

[0030] The plated material according to this disclosure will be primarily described as one obtained by transporting a substrate through an alternating magnetic field in a plating solution in which multiple magnetic media move randomly, and then electrically connecting the substrate to a cathode via the magnetic media for electroplating. However, it should not be limited to those electroplated using the electroplating apparatus described later in this disclosure. The specific configuration of the electroplating apparatus will vary depending on the type of plated material (e.g., fastener elements, sliders, or buttons). Frankly speaking, the plated material according to this disclosure is understood to be able to be manufactured not only by the electroplating apparatus and method illustrated in this application, but also by a variety of other electroplating apparatuses and methods.

[0031] Each magnetic medium continues to rotate or reverse in response to the alternating magnetic field. Therefore, although the electrical connection of the substrate to the cathode electrode via a single magnetic medium is instantaneous, the substrate can be continuously set to the cathode potential by introducing a large number of magnetic media into the plating solution. 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 will be described later, discontinuity occurs in the area distribution of crystal grains in the plating layer according to this application. This may not necessarily be the best from the perspective of aiming for the highest quality plating layer, but it is advantageous from the perspective of achieving both higher adhesion of the plating layer and a shorter electroplating process time. This point will become clearer from the explanation below.

[0032] TEM images are referenced as cross-sectional images to calculate the area of ​​the crystal grains. The TEM images are acquired to show the cross-section of the plating layer in the thickness direction of the plating layer. The TEM images are taken using a transmission electron microscope (model number: TalosF200X) manufactured by FE-I Japan Co., Ltd. and Hitachi Ha A scanning transmission electron microscope (model number: HD-2300A) manufactured by I Technologies will be used. The magnification ranges from 50,000x to 1,000,000x (however, even at equal magnification, the definition of magnification may differ depending on the transmission electron microscope device. Therefore, strictly speaking, it is appropriate to evaluate the degree of magnification by the width of the observation field. Based on this point, the observation field is also indicated in this specification). The TEM images in Figures 6 and 7 were acquired with 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 backward to disconnect them. The fastener stringers 2a, 2b have fastener elements 4a, 4b attached at a predetermined pitch to the opposing side edges of the fastener tapes 3a, 3b. The slide fastener 1 has left and right front fasteners that define the foremost position of the slider 7 and one rear fastener that defines the rearmost position of the slider 7, but these are optional. The slider 7 is a general type having an upper wing plate, a lower wing plate, and connecting columns that connect them, and a detailed description thereof will be omitted.

[0034] The slide fastener 1 extends in a long length in the front-to-back direction with a predetermined width from left to right and has high flexibility as a whole. The same applies to the fastener stringers 2a and 2b. The slide fastener 1 is attached and fixed to various articles such as clothing, bags, and shoes, and provides an openable and closable opening to the articles by opening and closing itself. The fastener tapes 3a and 3b are woven or knitted highly flexible fabrics, and core cords CY for fixing the fastener elements 4a and 4b are provided on their side edges. The width directions of the slide fastener 1, fastener stringers 2a and 2b, and fastener tapes 3a and 3b all coincide with the left-to-right direction.

[0035] The fastener elements 4a and 4b are made of a metal base material that has been electroplated. The fastener elements 4a and 4b include an engaging head 21 and a pair of legs 22 and 23 that extend in the same direction from the engaging head 21 (along the width direction of the fastener tapes 3a and 3b) and clamp the fastener tapes 3a and 3b. The engaging head 21 has an engaging projection 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 projection 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 projection 46 and the engaging recess 47 promote smooth and strong engagement between the left and right fastener elements 4a and 4b. The fastener elements 4a and 4b are not limited to the structure described above. For example, the engaging head 21 may also have a structure having a pair of engaging heads that protrude 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 Figure 1), they can observe the alternatingly arranged main surfaces 51 of the left and right fastener elements 4a and 4b. Each main surface 51 of the fastener elements 4a and 4b is oriented along (for example, parallel to) the upper or lower tape surface of the fastener tapes 3a and 3b, i.e., the tape surface that defines the thickness of the fastener tapes 3a and 3b. Each main surface 51 of the fastener elements 4a and 4b may extend in the width direction of the slide fastener 1 from the side edges of the fastener tapes 3a and 3b to intersect the central axis CX of the slide fastener 1.

[0037] As described above, the fastener elements 4a and 4b are made of a metal base material that has been electroplated. One purpose of this is to give the fastener elements 4a and 4b a desired metallic color, and in particular to give their main surface 51 a desired metallic color. By uniformly electroplating the main surface 51 of the fastener elements 4a and 4b, the appearance quality of the slide fastener 1 is improved. Of course, electroplating can also be performed for additional or alternative purposes, such as protecting the base material with a plating layer. The main surface 51 of the fastener elements 4a and 4b includes the main surface portion 51a formed on the engaging head 21 and the main surface portions 51b formed on the leg portions 22 and 23.

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

[0039] The front side surface 52 is connected to the front edge of the main surfaces 22m and 23m, the rear side surface 53 is connected to the rear edge of the main surfaces 22m and 23m, and the 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 surfaces perpendicular or substantially perpendicular to the plane on which the fastener tapes 3a and 3b exist. The end surface 54 is located furthest inward on the fastener elements 4a and 4b. The inward direction of the tape is from the outer position of the tape surface of the fastener tapes 3a and 3b to the position on the tape, and is perpendicular to the side edges of the fastener tapes 3a and 3b.

[0040] The engaging head 21 may have upper and lower main surfaces 21m formed continuously and adjacent to the main surfaces 22m and 23m of the legs 22 and 23 on the same plane, a tip surface 46j of the engaging projection 46, a first circumferential surface 46k formed around the tip surface 46j, a bottom surface 47j of the engaging recess 47, and a second circumferential surface 47k formed around the bottom surface 47j. The main surface 21m is a flat surface, similar to the main surfaces 22m and 23m, but is not limited to this. It goes without saying that chamfers can be applied to the edges between the surfaces of the fastener elements 4a and 4b.

[0041] In a fastener chain where the left and right fastener elements 4a and 4b are engaged in an alternating manner, the main surface 51 is more susceptible to impact from the magnetic media during the electroplating process than the front surface 52, rear surface 53, and end surface 54. For example, in one fastener stringer, the front surface 52 of the rear fastener element and the rear surface 53 of the front fastener element of two adjacent fastener elements face each other, defining a narrow liquid space between them. The magnetic media in the plating solution is more likely to move in the liquid space other than this narrow liquid space. Therefore, a better plating layer (particularly the first plating layer described later) can be formed on the main surface 51 than on the front surface 52 and rear surface 53 of the fastener elements 4a and 4b. The same applies to the relationship between the end surface 54 and the main surface 51, although to a different degree. In general terms, the plating layer (particularly the first plating layer described later) can be formed non-uniformly on different surfaces of the fastener elements 4a and 4b. The first plating layer between the front surface 52 and the rear 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 layer is outside the range of 0.8 to 1.2 times the thickness of the other layer. Typically, the first plating layer directly beneath the main surface 51 is thicker than the first plating layer elsewhere, but this is not always the case.

[0042] As described above, the main surfaces 51 of the fastener elements 4a and 4b are more susceptible to impact from the magnetic media during the electroplating process than the tip surface 46j and first circumferential surface 46k of the engaging projection 46, and the bottom surface 47j and second circumferential surface 47k of the engaging recess 47. For example, in the left and right fastener stringers 2a and 2b, 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 and 4b that are engaged with each other are positioned opposite each other with a small gap between them. The same applies to the tip surface 46j and the bottom surface 47j. The magnetic media in the plating solution is highly likely to move in locations other than the small gap mentioned above. Therefore, a better plating layer (particularly the first plating layer described later) can be formed on the main surface 51 than on the tip surface 46j, first circumferential surface 46k, bottom surface 47j and second circumferential surface 47k of the fastener elements 4a and 4b. Typically, the first plating layer directly beneath the main surface 51 is thicker than the first plating layer in other locations, but this is not always the case.

[0043] The explanation will be given with reference to Figure 4. Figure 4 schematically shows that the plating layer 84 and the metal substrate 83 are formed in this order from the main surface 51 of the fastener elements 4a and 4b toward the interior of the fastener elements 4a and 4b. The plating layer 84 includes the first and second plating layers 81 and 82 formed in this order on the substrate 83. As will be described later, the first plating layer 81 and the second plating layer 82 can be distinguished and observed by the difference in the area of ​​the crystal grains observable in the TEM image, but in reality, they are a single plating layer formed by a single or common electroplating process and apparatus. Furthermore, the plating layer described herein does not need to be formed in layers over the entire area of ​​the main surface 51 (unless this point is specifically stated), 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 metallic base material 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 in a plane parallel to the tape surface, the second plating layer, the first plating layer, the base material, 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 base material 83 contains one or more base metal elements. In some cases, the base material 83 contains copper (Cu) as the base metal element, and in other cases, the base material 83 contains copper (Cu) and zinc (Zn) as the base metal elements. The former means that the base material 83 consists of copper, and the latter means that the base material consists of brass (CuZn). Forms in which the base material 83 consists of other substitute or additional metal elements are also conceivable. As demonstrated in Patent Document 1, there are many candidate metal elements for the base material and plating layer, and it is not limited to any particular metal element. Furthermore, this specification does not consider trace amounts of unavoidable metal elements that are inevitably mixed into the metal.

[0046] The plating layer 84 includes a first plating layer metal element which is the same metal element as the base metal element, and a second plating layer metal element which is a different metal element from the base metal element. When 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. When 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 which 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 conceivable that the plating layer 84 may include multiple different metal elements as the second plating layer metal element.

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

[0048] In various preferred configurations, 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 in 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 in terms of achieving both higher adhesion of the plating layers and a shorter electroplating process time.

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

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

[0051] As can be seen from Figure 5, in the depth direction from the surface of the plating material toward the substrate, the first plating layer is formed on the substrate side of the intersection point P1 of the plot line PL1 representing the elemental ratio of the first plating layer metal element (Cu in Figure 5) and the plot line PL2 representing 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 plating material toward the substrate, the first plating layer is formed on the substrate side of the intersection point P1 of the plot line PL1 representing 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 representing the elemental ratio of the second plating layer metal element (Sn). This characteristic means that the first plating layer is formed thinly, which is advantageous in terms of achieving both higher adhesion of the plating layer and a shorter electroplating process time.

[0052] As can be seen from Figure 5, the intersection point P2 of the plot line PL3 representing the elemental ratio of the base metal element (Zn) with a lower elemental ratio among the base metal elements (Cu, Zn) and the plot line PL2 representing the elemental ratio of the second plating layer metal element (Sn) can be located within the thickness of the first plating layer. This characteristic means that the first plating layer is formed thinly, which is advantageous in terms of achieving both higher adhesion of the plating layer and shorter electroplating time.

[0053] In some cases, the spacing D1 between the intersection P1 and the first plating layer is 50 nm or more. This characteristic means that, in addition to the first plating layer 81 being formed thinly, the elemental ratio of the second plating layer metal element (Sn) in the first plating layer 81 is low. Depending on the combination of the first plating layer metal element and the second plating layer metal element, specific effects may be obtained. As an example of non-limiting cases, if 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 less than 40% tin. Speculum alloys do not discolor in the atmosphere, are hard and resistant to rust, and provide the effect of improved corrosion resistance and wear resistance. Typically, the spacing D1 between the intersection P1 and the first plating layer is 100 nm or less.

[0054] The following explanation will be given with reference to Figures 6 and 7. Figure 6 is a TEM (Transmission Electron Microscope) image (observation magnification 50,000x, observation field 2.5 μm × 1.9 μm) showing a cross-section of the plated material (specifically, a fastener element) according to this disclosure. Figure 7 is an enlarged image of the portion within the dotted line frame of the TEM image shown in Figure 6. The second plating layer 82 can be observed separately from the first plating layer 81 as a layer with larger crystal grains compared to the crystal grains of the first plating layer 81 (this feature is in contrast to the fact that the change in the elemental ratio of the metal elements in the first and second plating layers has continuity on both sides of the boundary line L2 between the first plating layer 81 and the second plating layer 82 (see Figure 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 malleability due to its larger crystal grains than the first plating layer 81.

[0055] Furthermore, while an uneven boundary line L1 caused by the difference in crystal grain area can be drawn in the TEM image between the substrate 83 and the first plating layer 81, a flat interface (as observed in conventional barrel plating) cannot be observed. Similarly, an uneven boundary line L2 caused by the difference in crystal grain area can be drawn between the first plating layer 81 and the second plating layer 82, but a flat interface (as observed in conventional barrel plating) cannot be observed. For an interface observed in conventional barrel plating, please refer to Figure 8 of Patent Document 1.

[0056] The first plating layer 81 is a layer made up of a plurality of densely packed first crystal grains, and the second plating layer 82 is a layer made up of a plurality of densely packed second crystal grains. In Figure 6 or Figure 7, it is possible to distinguish between a plurality of first crystal grains having a width of less than 100 nm and a plurality of second crystal grains having a width of more than 100 nm. Thanks to the difference in width between the first and second crystal grains, it is possible to achieve both higher adhesion of the plating layer and a shorter electroplating process time.

[0057] The areas of the first crystal grains and the second crystal grains can be calculated based on applying a rectangular frame to a TEM image at a desired magnification. In a TEM (Transmission Electron Microscope) image at a desired magnification (for example, the one shown in Fig. 6), when a rectangular frame is applied to one second crystal grain, half of the area of the rectangular frame can be calculated as the area of that second crystal grain. In a desired TEM image (for example, the one shown in Fig. 6 or one with a higher magnification), when a rectangular frame is applied to one first crystal grain, half of the area of the rectangular frame can be calculated as the area of that first crystal grain. The areas of a predetermined number, typically 10 or 20, of crystal grains can be calculated by the above method, and the average value of the areas of the crystal grains can be obtained. The average area of the second crystal grains observed in the TEM image is 10000 nm 2 or more, or 50000 nm 2 or more, or 100000 nm 2 or more. The average area of the first crystal grains observed in the TEM image is 1000 nm 2 or less, or 2000 nm 2 or less. The average area described here is based on the results calculated according to the above method for some samples of plating materials. Note that since the contour shapes of the first crystal grains and the second crystal grains observed in the TEM image are also various, half of the value of the rectangular frame is calculated as the area of the crystal grain. 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 for calculating the area of the second crystal grains can also be used.

[0058] Figs. 8 and 9 show the state where a rectangular frame is actually applied to a TEM image (observation magnification is 50,000 times, observation field of view is 2.5 μm × 1.9 μm) for calculating the area of the second crystal grains. In the TEM image ​A rectangular frame is set up so that a single second crystal grain is inscribed within its four sides. To simplify the adjustment of the rectangular frame's position, a small gap may exist between one side of the rectangular frame and the contour of the second crystal grain. This is justified by using a correction factor to calculate the area of ​​the second crystal grain, as described later. A rectangular frame in a TEM image includes the entire cross-section of one second crystal grain to which the rectangular frame applies (in other words, one second crystal grain entirely enclosed by the rectangular frame), and partial cross-sections of one or more other second crystal grains surrounding that second crystal grain. Depending on the position of the second crystal grain to which the rectangular frame applies, it may also include the entire or partial cross-sections of one or more first crystal grains. 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 included in the product of the lengths of the first side of the rectangular frame and the second side perpendicular to it. The correction factor is a number greater than 0 and less than 1, and in this disclosure, 0.5 is adopted.

[0059] Figure 10 shows the TEM image (observation magnification 200,000x, observation field 0.6 μm × 0.5 μm) with a rectangular frame actually applied to it for the calculation of the area of ​​the first crystal grain. Figures 11 and 12 are The image shows a rectangular frame applied to a TEM image (observation magnification 500,000x, observation field 0.3 μm × 0.2 μm) for the purpose of calculating the area of ​​the first crystal grain. The first crystal grain in the TEM image. The area is calculated in the same way as the method for calculating the area of ​​the second crystal grain in the TEM image described above. Preferably, since the first crystal grain is smaller than the second crystal grain, a TEM image acquired at a higher magnification than the TEM image used to calculate the second crystal grain is used. For reference, Figure 13 shows the state in which a rectangular frame is applied to the second crystal grain near the surface of the second plating layer, away from the first plating layer.

[0060] The explanation will be given with reference to Table 1 and Figure 14. In Table 1 and Figure 14, the area of ​​the crystal grains follows the method using the rectangular frame described above. EM1 in Figure 14 shows the area distribution of the first crystal grains in the plating layer 84 of the plating material shown in Figures 6 and 7. EM2 in Figure 14 shows the area distribution of the second crystal grains in the plating layer 84 of the plating material shown in Figures 6 and 7. EM3 in Figure 14 shows the area distribution of the crystal grains in the plating layer according to the comparative example in Patent Document 1. EM1 in Figure 14 shows the distribution of the area plots of the 20 first crystal grains shown in Table 1. EM2 in Figure 14 shows the distribution of the area plots of the 20 second crystal grains shown in Table 1. EM3 in Figure 14 shows the distribution of the area plots of the 20 second crystal grains shown in Table 1.

[0061] [Table 1-1] [Table 1-2]

[0062] As shown in Table 1, in the area distribution of crystal grains of the first plating layer 81, the maximum area of ​​the crystal grains is 4100 nm. 2 Therefore, in the area distribution of crystal grains of the second plating layer 82, the minimum surface area of ​​the crystal grains The product is 40,000 nm 2 Thus, the first plating layer 81 and the second plating layer 82 are Despite the continuity in the thickness direction of the plating layer 84, there is a large discrepancy in the area distribution of crystal grains (vertical axis in Figure 8) between the first plating layer 81 and the second plating layer 82. In some cases, the average area of ​​the second crystal grain (unit: nm) 2 ) This is the average area of ​​the first crystal grain (unit: nm) 2 It is greater than 10 times (or 50 times) the first conclusion. Thanks to the difference in area between the first and second crystal grains, it is possible to achieve both higher adhesion of the plating layer and a shorter electroplating process time.

[0063] [Table 2]

[0064] The variances of EM1 to EM3 shown in Table 2 were calculated based on the grain area shown in Table 1. The average grain area can be calculated using formula 1. The variance can be calculated using formula 2. For calculation purposes, the variance values ​​are expressed in exponential notation, and rational numbers are shown with two decimal places. The two decimal places are rounded.

number

number

[0065] The dispersion of the area distribution of the crystal grains in the first plating layer 81 (=6.2 × 10) 5 ) is the dispersion of the area distribution of the crystal grains of the second plating layer 82 (= 6.7 × 10 9 This is approximately 1 / 10000 of the original, satisfying the condition of 1 / 1000 or less (it may also satisfy any one of the following conditions 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). This means that the crystal grains of the first plating layer 81 are densely formed in comparison to the crystal grains of the second plating layer 82.

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

[0067] [Table 3]

[0068] Table 3 shows the results of calculating the standard deviation based on the variance shown in Table 2. The standard deviation for the area of ​​the crystal grains of the first plating layer 81 (=1163) is about 1 / 69 of the standard deviation for the area of ​​the crystal grains of the second plating layer 82 (=79897), satisfying the condition of being less than 1 / 10. (Any one of the following conditions may also be satisfied: 1 / 60 or less, 1 / 50 or less, 1 / 40 or less, 1 / 30 or less, and 1 / 20 or less). This means that the crystal grains of the first plating layer 81 are densely formed in comparison to the crystal grains of the second plating layer 82.

[0069] By forming a thicker second plating layer 82, the average area of ​​the second crystal grains may become larger than the average area of ​​the first crystal grains. Similarly, the dispersion of the area of ​​the second crystal grains may become larger than the dispersion 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 material observed in Table 1 and Figure 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] Furthermore, it is not practical to observe and calculate the area of ​​all first and second crystal grains contained in a given plating material. Therefore, to calculate the average area of ​​the crystal grains, it is preferable to calculate the average area based on a predetermined number of crystal grains (e.g., 18, 20, 30, 40, or 50) randomly selected in a TEM image at a desired magnification, as described above. 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. As an addition or alternative, a rule can be adopted in which, for the second selection, crystal grains with a larger area than those selected in the first selection are selected, and for the third selection, crystal grains with a smaller area than those selected in the second selection are selected. Increasing the number of samples allows for more accurate evaluation.

[0071] The following explanation will be given with reference to Figures 15 to 17. Figure 15 shows the case where the second plating layer metal element is tin, and Figures 16 and 17 show the case where the second plating layer metal element is copper (the base metal element is a metal element other than copper). From both figures (especially Figure 16), it can be seen that numerous indentations are formed on the surface of the fastener element, indicating that the surface of the fastener element has been given a matte finish. By making the plating layer 84 the outermost layer without forming an additional plating layer on top of the plating layer 84 in the plating material, the matte pattern obtained simultaneously with the electroplating process (from impact by magnetic media) can be exposed. When the plating material is a fastener element, in addition to the design effect of the matte pattern, an optical effect of reducing the glossiness of its main surface can also be obtained. Note that the indentations on the surface of the fastener element are not limited to being formed in a matte pattern. As shown in Figure 17, no indentations are formed on the bottom surface 47j of the engagement recess 47 of the fastener element. This confirms that the fastener element was electroplated using the electroplating method of this disclosure in the fastener chain state, thereby promoting efficient electroplating. The bottom surface 47j of the engaging recess 47 is not usually visible to the user, and the design of the fastener element is not impaired even if a pattern is not formed there.

[0072] The electroplating apparatus and process will be described in detail below with reference to Figures 18 to 27. In the description of the electroplating apparatus and process, as a general rule, the fastener elements 4a' and 4b' correspond to the base material 83 of the fastener elements 4a and 4b described above. Therefore, please note 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 standpoint of high production efficiency required for slide fasteners 1, instead of individually electroplating each fastener element 4a', 4b', the base material of the fastener elements is electroplated while 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). The following explanation assumes that the electroplating process is performed on a fastener chain, but it can also be understood as being performed on a fastener stringer.

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

[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 high speed, high productivity can be obtained, and the formation of crystal grains of the second plating layer 82, which are coarser than the crystal grains of the first plating layer 81, as shown in Figures 6 to 8, is promoted.

[0076] The process of generating an alternating magnetic field in the electrolyte may include rotating one or more magnetic rotating parts 60 (see Figure 20) in which different magnetic poles are alternately arranged in the direction of rotation. These are housed in a rotatable, sealed magnetic permeable housing 70 (see Figure 21). The outer surface of the magnetic permeable housing 70 is provided with a plurality of support members 78 for supporting the fastener chain 1' (see Figure 18), defining its transport path. As the magnetic rotating parts 60 rotate at high speed within the magnetic permeable housing 70, the magnetic pole closest to a given fastener element 4a', 4b' continuously alternates between the north and south poles, as shown in Figures 19(a) and 19(b). In this way, the magnetic media 9 moves randomly and collides with the fastener elements 4a', 4b' and the plating layer growing on them as they travel along the transport path.

[0077] The following provides a more detailed explanation. As shown in Figure 18, the electroplating apparatus 100 includes a plating tank 30, a transport mechanism 40, an alternating magnetic field generating unit 50, and a travel path 80 for the fastener chain 1'. The fastener chain 1' enters the plating tank 30 from outside via rollers 41 and 42 of the transport mechanism 40, and exits the plating tank 30 from inside via rollers 43 and 44 of the transport 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 tank and an external sub-tank. From the viewpoint of reducing environmental impact, it is preferable to use a plating solution that does not contain specific hazardous substances such as cyanide, chromium, and selenium. The cathode 10 and anode 20 are connected to a DC power supply 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 according to the metal element of the second plating layer. The cathode 10 is provided in the electrolyte 35, away from the anode 20, in order to supply electrons to the fastener elements 4a', 4b' (to make the fastener elements 4a', 4b' cathode potential).

[0079] The alternating magnetic field generator 50 generates an alternating magnetic field in the electrolyte 35 of the plating tank 30. An alternating magnetic field is a magnetic field whose magnitude and direction change over time. The travel path 80 of the fastener chain 1' is provided so that the fastener chain 1' is positioned within the alternating magnetic field generated by the alternating magnetic field generator 50. When the generation of the alternating magnetic field and the travel of the fastener chain 1' occur simultaneously or for the same period of time, the fastener elements 4a', 4b' of the fastener chain 1' pass through the alternating magnetic field generated by the alternating magnetic field generator 50.

[0080] The cathode 10 is provided so as to allow multiple magnetic media to move (e.g., rotate) in response to the alternating magnetic field between the cathode 10 and the fastener elements 4a', 4b' of the fastener chain 1' supported by the support member 78, and so as to be electrically connectable to the fastener elements 4a', 4b' via the multiple magnetic media. In other words, (i) a space is provided between the cathode 10 and the fastener elements 4a', 4b' of the fastener chain 1' supported by the support member 78, in which multiple magnetic media move in response to the alternating magnetic field, and (ii) this space is configured such that the fastener elements 4a', 4b' are electrically connected to the cathode 10 via the multiple magnetic media, and the multiple magnetic media can collide with the plating layer growing on the fastener elements 4a', 4b'.

[0081] According to the above configuration, it is possible to ensure 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., with sufficient processing resistance). Furthermore, when the fastener chain is run continuously or intermittently along the travel path 80 defined by the support member 78, the electroplating process can be carried out efficiently.

[0082] The support member 78 may be provided to control the position and orientation of the fastener chain 1' such that the longitudinal direction of the fastener chain 1' is aligned with a predetermined direction in which different magnetic poles are alternately arranged for the generation of an alternating magnetic field (for example, the circumferential direction and / or rotational direction of the magnetic rotating part 60 described later), and the fastener chain 1' faces the magnetic poles in a flat position in its width direction. This facilitates 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., N poles and S poles) are arranged alternately in the direction of rotation. Permanent magnets, electromagnets, or a combination thereof can be used as magnetic poles. In the case shown in Figure 20, permanent magnets are used for the magnetic poles. The magnetic rotating unit 60 has a rotating body 63 rotatably fixed to the rotation shaft 62 of the motor 61, and a plurality of permanent magnets 64 provided on 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 may be rare earth magnets such as neodymium magnets, but other types can also be used. It is not necessary to provide one motor 61 corresponding to one magnetic rotating unit 60. The output of the motor 61 can also be supplied to multiple magnetic rotating units 60 via a suitable power transmission system. Furthermore, the rotating shaft 62 of the motor 61 can be fixed to the opening in the bottom plate 31 of the plating tank 30 via a waterproof bearing.

[0084] Multiple permanent magnets 64 are arranged such that the south poles and north poles alternate in the rotation direction of the magnetic rotating part 60 (see Figure 20). When the magnetic rotating part 60 rotates in response to the operation of the motor 61, the magnetic rotating part 60 is alternately switched between south pole and north pole when viewed from a predetermined position radially outside the magnetic rotating part 60. A magnetic medium (e.g., pin media) located at the predetermined position radially outside the magnetic rotating part 60 rotates in accordance with the change in the magnetic pole (closest to the magnetic medium) and flows in the rotation direction of the magnetic rotating part 60. The rotation speed of the magnetic rotating part 60 is, for example, 100 to 4,000 rpm.

[0085] As shown in Figure 20, the outer surface of the magnetic rotating part 60 may be alternately provided with N-pole zones Z1, Z3, Z5, where permanent magnets 64 with their N poles facing outward, and S-pole zones Z2, Z4, where permanent magnets 64 with their S poles facing outward, in the direction of rotation of the magnetic rotating part 60. In Figure 20, the N-pole zones Z1, Z3, Z5 and the S-pole zones Z2, Z4 extend straight up and down parallel to the rotation axis of the magnetic rotating part 60, but the configuration is not limited to this. In some cases, considering the sedimentation of the magnetic media due to gravity, the N-pole zones Z1, Z3, Z5 and the S-pole zones Z2, Z4 may extend diagonally up and down non-parallel to the rotation axis of the magnetic rotating part 60, or extend in a zigzag pattern up and down non-parallel to the rotation axis of the magnetic rotating part 60.

[0086] The electroplating apparatus 100 further includes a magnetic permeable housing 70, in which the magnetic rotating part 60 is housed in a rotatable and airtight manner. The magnetic permeable housing 70 allows the magnetic flux of the permanent magnet 64 of the magnetic rotating part 60 inside to pass through from the N pole to the S pole, enabling the formation of a magnetic field outside the magnetic permeable housing 70. The magnetic permeable housing 70 does not rotate with the magnetic rotating part 60 based on the operation of the motor 61, but remains stationary in a predetermined position and is coupled to the rotating shaft 62, for example (by its bottom plate and top plate) via waterproof bearings. By providing the magnetic permeable housing 70, the magnetic rotating part 60 can be protected from the electrolyte 35 and / or the rotational resistance of the magnetic rotating part 60 can be reduced. The magnetic permeable housing 70 is made of a resin such as polypropylene, acrylic, or polyvinyl chloride.

[0087] Multiple support members 78 are provided on the outer surface of the magnetic permeable housing 70 as one or more support devices for supporting the fastener chain 1'. This controls the position and orientation of the fastener chain 1' and defines its travel path 80. Preferably, the fastener chain 1' is supported in a flat position by the support devices (e.g., support members 78). The fastener chain 1' can travel circumferentially around the magnetic rotating part 60, specifically at a position radially outside the rotation axis 62 of the magnetic rotating part 60. Although the magnetic flux density decreases as the distance from the magnetic rotating part 60 increases radially, the support members 78 on the magnetic permeable housing 70 allow the fastener chain 1' to travel in close proximity to the magnetic rotating part 60. The magnetic media can move significantly in response to the alternating magnetic field between the magnetic permeable housing 70 and the fastener chain 1', and the magnetic media can strongly collide with the plating layer. In some cases, multiple support members 78 are attached to the outer surface of the magnetic permeable housing 70 so as to define the helical travel path 80 of the fastener chain 1'. By making the travel track 80 spiral-shaped, it is possible to avoid increasing the size of the electroplating apparatus 100.

[0088] Each support member 78 is an L-shaped member, and more specifically, has a first rod portion 78a extending radially outward from the rotation axis 62 of the magnetic rotating part 60, and a second rod portion 78b extending upward at a predetermined distance 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, etc. The support members 78 can be fixed to the outer circumference of the magnetic permeable housing 70 by any method such as screwing or adhesive.

[0089] A cathode 10 can be provided on the outer surface of the magnetic permeable housing 70. The cathode 10 is provided so as to extend along the travel path of the fastener chain 1'. This is expected to ensure good electrical connection between the fastener elements 4a', 4b' and the cathode 10 via the magnetic media. In some cases, the cathode 10 is provided spirally around the magnetic permeable housing 70, corresponding to the spiral travel path 80 of the fastener chain 1'. As an addition or alternative, the cathode 10 is provided at a position where the fastener elements 4a', 4b' of the fastener chain 1' are facing the cathode 10 as they travel along the travel path 80. The permanent magnet 64, magnetic permeable housing 70, cathode 10, magnetic media, and fastener elements 4a', 4b' are arranged coaxially in the radial direction with respect to the rotation axis of the magnetic rotating part 60.

[0090] When a cathode 10 is provided on the outer surface of a magnetic permeable housing 70, the rotation of the magnetic rotating part 60 induces an electromotive force in the cathode 10, causing an induced current to flow in the cathode 10. To reduce this effect, the cathode 10 is provided linearly (instead of cylindrically) on the outer surface of the magnetic permeable housing 70. This reduces the magnetic flux linked to the cathode 10, thereby suppressing the induced electromotive force and induced current. A helical cathode 10 can be constructed by spirally winding a linear cathode 10 onto the outer surface of the magnetic permeable housing 70. A linear cathode 10 can be provided on the outer surface of the magnetic permeable housing 70 in a manner other than spiral. The cathode 10 can be fixed to the outer surface of the magnetic permeable housing 70 by methods such as screws, adhesives, or fitting.

[0091] If the cathode 10 is provided in a linear or helical shape, the length of the cathode 10 becomes long. To stabilize the cathode potential, multiple contacts with the DC power supply E1 can be provided on the cathode 10 within a single permeable housing 70, or the cathode 10 can be divided and contacts with the DC power supply E1 can be provided individually.

[0092] A frame 72 can be used to position anodes 20 near the travel path 80 of the fastener chain 1' (see Figure 22). Multiple anodes 20 can be positioned at different locations along the travel path 80 of the fastener chain 1' by directly or indirectly attaching them to the frame 72 via a basket or the like. This reduces the uneven distribution of metal ion concentration along the travel path 80 of the fastener chain 1'. For example, a mesh basket can be attached to the frame 72, and metal plates (which function as anodes 20) can be placed inside the basket.

[0093] The frame 72 is located radially outward from the magnetic 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 in the vertical direction. The frame 72 is constructed so as not to interfere with the travel path 80 of the fastener chain 1'. Metal ions eluting from the anode 20 can reach the fastener elements 4a', 4b' of the fastener chain 1' located in the travel 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 placed near the travel 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 north pole zone of the magnetic rotating part 60 is located inside the permeable housing 70 at a predetermined position on its outer circumference. In Figure 19(b), the south pole zone of the magnetic rotating part 60 is located inside the permeable housing 70 at a predetermined position on its outer circumference. In both Figure 19(a) and Figure 19(b), an appropriate amount of magnetic media 9 is present between the cathode 10 and the fastener elements 4a', 4b', where the magnetic flux is shown by the dashed line.

[0095] During the process of the magnetic flux direction changing from Figure 19(a) to Figure 19(b), each magnetic medium 9 rotates and displaces. Regardless of the changes in orientation and displacement of each magnetic medium 9, the fastener elements 4a', 4b' can be electrically connected to the cathode 10 via multiple media before, during, or throughout the process. Some magnetic media 9 collide with the growing plating layer on the fastener elements 4a', 4b' during their rotation. 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 medium 9.

[0096] While not always the case, the magnetic media 9 can be used to assist in the transport of the fastener chain 1'. For example, the rotation direction of the magnetic rotating part 60 and the direction of travel 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 flows in the same direction as the magnetic rotating part 60, accompanied by the permanent magnet 64 of the magnetic rotating part 60. This flow of the magnetic media 9 pushes the fastener chain 1', making it easier for the fastener chain 1' to travel in the same direction.

[0097] The fastener elements 4a' and 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 Figure 19). Assuming that the anode 20 is positioned radially outward from the fastener chain 1' in the magnetic permeable housing 70, and that equivalent magnetic media exist on the first surface 5 side and the second surface 6 side of the fastener elements 4a' and 4b', the growth rate of the plating layer on the second surface 6 side of the fastener elements 4a' and 4b' will be greater than the growth rate of the plating layer on the first surface 5 side of the fastener elements 4a' and 4b'. To suppress differences in the thickness of the plating layer on the front and back sides of the fastener elements 4a' and 4b', it is preferable to reverse the front and back sides of the fastener chain 1' along its path.

[0098] As shown in Figure 18, the plating tank 30 is provided with two alternating magnetic field generating units 50. An upstream spiral travel path is provided on the outer circumference of the permeable housing 70 of the upstream alternating magnetic field generating unit 50, and a downstream spiral travel path is provided on the outer circumference of the permeable housing 70 of the downstream alternating magnetic field generating unit 50. Between these spiral travel paths, there is a front-to-back reversal section 90 for the fastener chain 1'.

[0099] As shown in Figure 23, the front-to-back reversal section 90 has only two guide rollers 91 and 92. The front-to-back reversal of the fastener chain 1' is achieved by reversing the direction of travel of the fastener chain 1' between the upstream magnetic permeable housing 70 and the downstream magnetic permeable housing 70. That is, as shown in Figure 23, when the plating tank 30 is viewed from above, the fastener chain 1' travels clockwise in the upstream helical travel path and counterclockwise in the downstream helical travel path. In this way, the front and back of the fastener chain 1' are reversed, and uniformity of the plating layer thickness on the front and back of the fastener elements 4a' and 4b' is promoted. Note that the front-to-back reversal of the fastener chain 1' can be performed by various other methods.

[0100] The operation method of the electroplating apparatus 100 will be explained focusing on a predetermined portion of the fastener chain 1'. First, in response to the transport of the fastener chain 1', a predetermined portion of the fastener chain 1' is guided by rollers 41 and 42 to the travel path 80 in the electrolyte 35. Before the predetermined portion of the fastener chain 1' travels along the travel 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 travel path 80 of the fastener chain 1' is positioned within the alternating magnetic field, where the magnetic media 9 moves. 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, its fastener elements 4a' and 4b' are electrically connected to a cathode 10 provided on the outer surface of the magnetic permeable housing 70 via a magnetic medium 9. Furthermore, the magnetic medium 9 repeatedly collides with the plating layer formed on the fastener elements 4a' and 4b'. During the period when the predetermined portion of the fastener chain 1' travels from the lower end to the upper end of the helical travel path 80, the growth of the plating layer and the collision of the magnetic medium 9 with the plating layer occur continuously. In this way, the formation of a plating layer of sufficient thickness is facilitated while avoiding an increase in the size of the electroplating apparatus 100.

[0102] A predetermined portion of the fastener chain 1' is then flipped over and travels in the reverse direction along the next spiral travel path 80, that is, from its upper end to its lower end. During this travel 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, a plating layer is formed on both the front and back surfaces of the fastener elements 4a' and 4b' of the fastener chain 1'. After completing its journey along the spiral travel path 80, the predetermined portion of the fastener chain 1' is guided by rollers 43 and 44 and exits the electrolyte solution 35.

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

[0104] In the above description, we mainly referred to Figure 18 to explain a configuration in which two alternating magnetic field generating units 50, two helical travel paths, and one front / back reversal unit 90 are provided. However, a configuration in which only one alternating magnetic field generating unit 50 and one helical travel path are provided is also conceivable. The travel path 80 of the fastener chain 1' is not necessarily limited to a helical shape; it can also be straight, zigzag, etc. Furthermore, the fastener chain 1' can be serpentinely stretched across multiple permeable housings 70, and this can be repeated along the rotation axis of the magnetic rotating unit 60.

[0105] The variations will be explained below with reference to Figures 24 to 27. Figures 24 and 25 show a configuration in which four alternating magnetic field generating units 50, four helical travel paths, and two front / back reversal units 90 are provided. In Figure 24, the fastener chain 1' travels clockwise upward along the first helical travel path, counterclockwise downward along the second helical travel path, counterclockwise upward along the third helical travel path, and clockwise downward along the fourth helical travel path. In Figure 25, the fastener chain 1' travels counterclockwise upward along the first helical travel path, clockwise downward along the second helical travel path, clockwise upward along the third helical travel path, and counterclockwise downward along the fourth helical travel path. By providing four or more alternating magnetic field generating units 50 and four helical travel paths, a sufficient plating layer thickness can be ensured even when the travel speed of the fastener chain 1' is increased.

[0106] Figures 26 and 27 show a configuration in which the orientation of the fastener chain 1' is maintained by the rollers 41 and 42 of the conveying mechanism 40, rather than the support member 78 (i.e., the rollers 41 and 42 of the conveying mechanism 40 function as supports for the fastener chain 1'). In this case as well, the same effects as described above can be obtained within a reasonable range.

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

[0108] Examples A plating layer was formed on the fastener elements of a fastener chain using the plating apparatus shown in Figure 24 of this application. The rotation speed of the magnetic rotating part was 400 rpm. The travel 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 a 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. This formed a first plating layer with a thickness of 50 nm to 150 nm, and a second plating layer with a thickness of 300 nm to 500 nm. A matte pattern was formed on the outermost surface of the second plating layer due to collisions with the magnetic media. The TEM image is shown in Figure 6.

[0109] Based on the above teachings, those skilled in the art can make various modifications to each embodiment and feature. The reference numerals included in the claims are for reference only and should not be used to limit the scope of the claims. [Explanation of symbols]

[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 material comprising a substrate (83) containing at least one base 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 substrate (83), wherein each of the first and second plating layers (81, 82) includes at least a first plating layer metal element which is the same metal element as the substrate metal element, and a second plating layer metal element which is a different metal element from the substrate metal element. The elemental ratio of the metal elements in the first plating layer decreases continuously as it moves away from the substrate (83) over at least 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 increases continuously as it moves away from the substrate (83) over at least the total thickness of the first and second plating layers (81, 82). A plated material in which the second plating layer (82) is observable in a first TEM (Transmission Electron Microscope) image as a layer with larger crystal grains compared to the crystal grains of the first plating layer (81), thereby distinguishing it from the first plating layer (81).

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

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

4. When a rectangular frame is applied to the first crystal grain in the first TEM image or a second TEM (Transmission Electron Microscope) image with a higher magnification, and half the area of ​​the rectangular frame is determined as the area of ​​the first crystal grain, the average area of ​​the first crystal grain in the second TEM image is 2000 nm. 2 The following, or 1000 nm 2 The plating material according to claim 3, which is as follows:

5. The average area of ​​the second crystal grain in the first TEM image is greater than 5 or 10 times the average area of ​​the first crystal grain in the second TEM image, and the average areas of the first and second crystal grains are the same in units of nm. 2 The plating material according to claim 4, as represented by [the specified formula].

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

7. The plating material according to any one of claims 1 to 6, wherein no flat interface is observed between the first plating layer (81) and the second plating layer (82) in the first TEM image, and / or no flat interface is observed between the substrate (83) and the first plating layer (81) in the first TEM image.

8. The plating material according to any one of claims 1 to 6, wherein the thickness of the first plating layer (81) is smaller than the thickness of the second plating layer (82).

9. The plating material according to any one of claims 1 to 6, wherein the thickness of the first plating layer (81) is 200 nm or less or 150 nm or less.

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

11. The plating material according to any one of claims 1 to 6, wherein in the depth direction from the surface of the plating material toward the substrate (83), the first plating layer (81) is formed on the substrate (83) side of the intersection (P1) of the plot line (PL1) of the elemental ratio of the metal elements of the first plating layer and the plot line (PL2) of the elemental ratio of the metal elements of the second plating layer.

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) contains a speculum alloy.

14. The plating material according to any one of claims 1 to 6, wherein the surface of the second plating layer (82) has numerous indentations.

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

16. The plating material is fastener elements (4a, 4b) attached to fastener tapes (3a, 3b), and the fastener elements (4a, 4b) include at least a partially textured surface, according to any one of claims 1 to 6.

17. A fastener stringer (2a, 2b) comprising fastener tapes (3a, 3b) and a plurality of fastener elements (4a, 4b) attached at a predetermined pitch to the side edges of the fastener tapes (3a, 3b), Each 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 substrate (83), wherein each of the first and second plating layers (81, 82) includes at least a first plating layer metal element which is the same metal element as the substrate metal element, and a second plating layer metal element which is a different metal element from the substrate metal element. The elemental ratio of the metal elements in the first plating layer decreases continuously as it moves away from the substrate (83) over at least 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 increases continuously as it moves away from the substrate (83) over at least the total thickness of the first and second plating layers (81, 82). A fastener stringer in which the second plating layer (82) can be observed in a TEM (Transmission Electron Microscope) image as a layer with larger crystal grains compared to the crystal grains of the first plating layer (81).

18. The fastener stringer according to claim 17, wherein the fastener elements (4a, 4b) have a main surface (51) oriented along the tape surface that defines the 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), The fastener stringer according to claim 18, wherein each leg of the pair of legs (22, 23) includes a front side surface (52) connected to the front edge of the main surface (51) and a rear side surface (53) connected to the rear edge of the main surface (51), and the second plating layer (82), the first plating layer (81), the substrate (83), the first plating layer (81), and the second plating layer (82) are formed in this order between the front side surface (52) and the rear side surface (53).

Images