Tinned product, method for producing the same, use of the tinned product and method for producing a terminal block comprising the tinned product

Abstract

Tinned product, comprehensive: a base material (10) made of copper or a copper alloy; a copper-tin alloy layer (12) formed on the base material (10), and a tin layer (14) formed on the copper-tin alloy layer (12), wherein the tinned product has a luster of 0.3 to 0.7 and the outermost surface of the tinned product has a mean height Rc of 0.1 to 1.0 µm.

Description

Technical field

[0001] The present invention relates generally to a tinned product and a method for producing it. More specifically, the invention relates to a tinned product which is used as the material for an insertable and extendable terminal block or the like, and a method for producing it. State of the art

[0002] Tin-plated products are commonly used as materials for insertable and retractable terminal blocks, where a tinning film forms the outermost layer of a conductive material such as copper or a copper alloy. Specifically, tin-plated products are used in information communication equipment for motor vehicles, mobile phones, and personal computers; control substrates for industrial equipment such as robots; connectors such as terminal blocks, cable frames, relays, and switches; and busbars due to their low contact resistance, contact reliability, corrosion resistance, solderability, cost-effectiveness, and other properties.

[0003] Tinning is typically carried out by electroplating. After electroplating, a reflow treatment (tin remelting treatment) is performed to remove internal stress in tinned products and suppress the formation of whiskers (needle-shaped single crystals). Therefore, when the reflow treatment is performed after tinning, some of the tin diffuses to the components of the underlying layer to form a compound layer, and a tin or tin alloy layer is formed on top of this.

[0004] A tinned product produced by such a reflow treatment is proposed in which a pure tin layer is formed on a copper-tin compound layer formed on a base material of copper or a copper alloy, wherein the thickness of the pure tin layer is in the range of 0.3 µm to 1.5 µm, and wherein the average particle diameter of the copper-tin compound layer on a surface that is substantially parallel to the interfaces between the layers of the tinned product is 1.3 µm or more, and wherein the arithmetic mean roughness Ra of the surface of the tinned product is 0.15 µm or more (see, for example, patent document 1).

[0005] Tin-plated products are also proposed, such as a connector terminal, wherein a nickel layer, a copper-tin alloy layer, and a tin layer, in that order, are formed as surface coverings on a copper alloy rod, and wherein the tin layer is smoothed by a reflow treatment (see, for example, patent document 2); a copper or copper alloy rod having a molten tinning layer, wherein the specular reflection of its surface is in the range of 25 to 65 (see, for example, patent document 3); and an electrically conductive material for joining parts, wherein a tin covering layer is formed on a copper-tin alloy covering layer formed on the surface of a base material made of a copper alloy rod, and wherein the surface thereof is reflow treated to cause part of the copper-tin alloy layer to be exposed on the surface of the tin covering layer (see, for example, patent document 3).B. Patent document 4). Furthermore, a tin-plated material is known which comprises a base material made of copper, an outer tin layer and an intermediate copper-tin mixed layer and which has an optical density of less than 1.0 (see e.g. patent document 5). Document(s) relating to the state of the art Patent document(s) Patent document 1: Japanese patent disclosure no. JP 2013 - 76 122 A (paragraph number 0013) Patent document 2: Japanese patent disclosure no. JP 2013 - 139 640 A (paragraph numbers 0011-0016) Patent document 3: Japanese patent disclosure no. JP 2014 - 198 889 A (paragraph number 0017) Patent document 4: Japanese patent disclosure no. JP 2014 - 208 904 A (paragraph number 0007) Patent document 5: Japanese patent disclosure no. JP 2012 - 201 932 A (paragraph number 0021) Summary of the invention: Problem to be solved by the invention

[0006] In each of the conventional tin-plated products proposed in patent documents 1-5, the hard tin-copper alloy layer is formed on the underside of the soft, pure tin layer by the reflow treatment as the outermost layer, so that it is possible to suppress the exposure of the base material as a result of sliding when it is used as the material of an insertable and retractable terminal or the like.

[0007] However, if such a tinned product is used as the material for automotive connectors, a problem arises in that the outermost pure tin layer is easily worn by sliding over a small distance (approximately 50 µm) between the contact points of plug and socket connections due to vibrations during vehicle operation (where the connection is held in a high-temperature environment). This tiny sliding wear (fretting corrosion) degrades the contact reliability of the connection. In particular, in the plug-in terminal of the tinned product, when the contact load is reduced, the contact point moves slightly, making it difficult to suppress this tiny sliding wear.

[0008] It is therefore an objective of the present invention to eliminate the aforementioned problems and to provide a tinned product which exhibits excellent resistance to minute sliding wear after being held in a high-temperature environment, and a method for producing the same. Means to solve the problem

[0009] To achieve the aforementioned goal, the inventors carefully investigated and determined that it is possible to provide a tin-plated product exhibiting excellent resistance to minute sliding wear after being held in a high-temperature environment, and a method for producing the same, if the tin-plated product, comprising a tin layer formed on a copper-tin alloy layer on a copper or copper alloy base material, has a luster of 0.3 to 0.7 and the outermost surface of the tin-plated product has an average height Rc of 0.1 to 1.0 µm. Therefore, the inventors have made the present invention.

[0010] According to the present invention, a tin-plated product is provided, comprising: a base material of copper or a copper alloy; a copper-tin alloy layer formed on the base material; and a tin layer formed on the copper-tin alloy layer, wherein the tin-plated product has a gloss of 0.3 to 0.7 and the outermost surface of the tin-plated product has an average height Rc of 0.1 to 1.0 µm.

[0011] In this tin-plated product, the tin layer preferably has a structure obtained by solidification after melting. The outermost surface of the tin-plated product preferably has an arithmetic mean roughness Ra of 0.05 to 0.20 µm. The outermost surface of the tin-plated product preferably has an oil retention depth Rvk of 0.03 to 0.20 µm and preferably a mean rough curve element length RSm of 2 to 7 µm. Furthermore, a nickel layer or a nickel alloy layer is preferably formed between the base material and the copper-tin alloy layer, and a lubricant layer is preferably formed on the tin layer. Moreover, the tin layer is preferably formed over the entire surface of the copper-tin alloy layer.

[0012] According to the present invention, a method for producing a tinned product is provided, wherein the method comprises the steps of: applying a tinning layer with a thickness of 0.4 to 3 µm to the surface of a base material made of copper or a copper alloy by electroplating at a current density of 5 to 13 A / dm² 2The tinning layer is formed in a tinning bath consisting of water, tin sulfate, sulfuric acid, and a surfactant; the surface of the tinning layer is dried; the dried surface of the tinning layer is heated to melt the tin; and the heated surface of the tinning layer is cooled to cause a layer of the tinning layer on the outermost surface to be a tin layer exhibiting a structure obtained by solidification after melting, while a layer of the tinning layer between the tin layer and the base material is a copper-tin alloy layer. In this process for producing a tinned product, a lubricant is preferably applied to the tin layer to form a lubricant layer.

[0013] According to the present invention, a connection is provided which uses the tinned product described above as one of its materials. Effects of the invention

[0014] According to the present invention, it is possible to produce a tinned product that exhibits excellent resistance to minute sliding wear after being held in a high-temperature environment, even when a volatile lubricant is applied to it. Brief description of the drawings Fig. Figure 1 is a sectional view schematically showing the preferred embodiment of a tinned product according to the present invention. Fig. Figure 2 is a scanning ion microscope image (SEM image) of the surface of a tinned layer obtained in Example 2; and Fig. Figure 3 is a SEM image of a cross-section of the tinning layer obtained in Example 2. Method for carrying out the invention

[0015] With reference to the attached drawings, the preferred embodiment of a tinned product and a method for producing it according to the present invention are described in detail below.

[0016] As in Fig. As shown in Figure 1, in a preferred embodiment of a tin-plated product according to the present invention, a copper-tin alloy layer 12 is formed on a base material 10 made of copper or a copper alloy, and a tin layer 14 is formed on the copper-tin alloy layer 12 (the outermost surface) of the tin-plated product and has a gloss of 0.3 to 0.7. This gloss of the tin-plated product is lower than the gloss of conventional, reflow-treated tin-plated products and is in the range of dull to semi-bright. The outermost surface of the tin-plated product also has an average thickness Rc of 0.1 to 1.0 µm.

[0017] In this tin-plated product, the tin layer 14 is preferably a tin layer with a structure obtained by solidification after melting. The tin layer 14 is preferably formed over the entire surface of the copper-tin alloy layer 12. Furthermore, the copper-tin alloy layer 12 can be exposed on a portion of the outermost surface of the tin-plated product.

[0018] A lubricant layer 16 is preferably formed on the tin layer 14. If the lubricant layer 16 is formed on the tin layer 14 in this way, when the tinned product is used as the material for an insertable and removable terminal block, it is possible to suppress the oxidation of abrasive powder due to minute sliding wear, thus suppressing the increase in contact resistance and increasing the reliability of the electrical connection. Furthermore, even if the copper-tin alloy layer 12 is exposed due to minute sliding wear, the lubricant can suppress the oxidation of abrasive powder due to minute sliding wear. If the gloss of the surface of the tinned product is less than 0.3, the convexity-concavity (irregularity) of the surface is too great.When a lubricant is applied to such a surface to form the lubricant layer 16, a difference in the holding power of the lubricant layer 16 arises between the strong and weak sections. In the weaker section, it is not possible to sufficiently suppress the oxidation of the abrasive powder due to minute sliding wear, so the resistance to minute sliding wear is slightly impaired. Conversely, if the gloss exceeds 0.7, the convexity-concavity (irregularity) of the surface of the tinned product is too small (too flat). When a lubricant is applied to such a surface to form the lubricant layer 16, the holding power of the lubricant layer 16 is weak.For this reason, it is not possible to sufficiently maintain the effect of suppressing the oxidation of the abrasive powder due to the minute sliding wear, so that the resistance to minute sliding wear is slightly impaired.

[0019] The arithmetic mean roughness Ra of the outermost surface of the tinned product is preferably 0.05 to 0.20 µm and more preferably 0.09 to 0.18 µm. If the arithmetic mean roughness Ra of the outermost surface of the tinned product is less than 0.05 µm, the convexity-concavity (irregularity) of the surface of the tinned product is too small (too flat). If a lubricant is applied to such a surface to form the lubricant layer 16, the holding force of the lubricant layer 16 is weak. For this reason, it is not possible to sufficiently maintain the effect of suppressing the oxidation of the abrasive powder due to minute sliding wear, so that the resistance to minute sliding wear is slightly impaired.On the other hand, if the arithmetic mean roughness Ra of the outermost surface of the tinned product exceeds 0.20 µm, the convexity-concavity (irregularity) of the surface is too large. If a lubricant is applied to such a surface to form the lubricant layer 16, a difference in the holding power of the lubricant layer 16 will simply occur between the strong and weak sections. In the weak section, it is not possible to sufficiently suppress the oxidation of the abrasive powder due to minute sliding wear, so the resistance to minute sliding wear is slightly impaired.

[0020] The mean height Rc of the outermost surface of the tinned product is preferably 0.1 to 0.7 µm. If the mean height Rc of the outermost surface of the tinned product is less than 0.1 µm, the convexity-concavity (irregularity) of the surface of the tinned product is too small (too flat). If a lubricant is applied to such a surface to form the lubricant layer 16, the holding force of the lubricant layer 16 is weak. For this reason, it is possible to sufficiently maintain the effect of suppressing the oxidation of the abrasive powder due to minute sliding wear, so that the resistance to minute sliding wear is slightly impaired. On the other hand, if the mean height Rc of the outermost surface of the tinned product exceeds 1.0 µm, the convexity-concavity (irregularity) of the surface is too large.When a lubricant is applied to such a surface to form the lubricant layer 16, a difference in the holding force of the lubricant layer 16 is created between the strong and weak sections. In the weak section, it is not possible to sufficiently suppress the oxidation of the abrasive powder due to minute sliding wear, so the resistance to minute sliding wear is slightly impaired.

[0021] The oil retention depth Rvk of the outermost surface of the tinned product is preferably 0.03 to 0.20 µm and more preferably 0.03 to 0.16 µm. If the oil retention depth Rvk of the outermost surface of the tinned product is less than 0.03 µm, it is too shallow. If a lubricant is applied to such a surface to form the lubricant layer 16, the holding force of the lubricant layer 16 is weak. For this reason, it is not possible to adequately maintain the effect of suppressing the oxidation of the abrasive powder due to minute sliding wear, so that the resistance to minute sliding wear is slightly impaired. On the other hand, if the oil retention depth Rvk of the outermost surface of the tinned product exceeds 0.20 µm, it is too deep.When a lubricant is applied to such a surface to form the lubricant layer 16, a difference in the holding force of the lubricant layer 16 is created between the strong and weak sections. In the weak section, it is not possible to sufficiently suppress the oxidation of the abrasive powder due to minute sliding wear, so the resistance to minute sliding wear is slightly impaired.

[0022] The mean roughness length RSm of the outermost surface of the tinned product is preferably 2 to 7 µm. If the mean roughness length RSm of the outermost surface of the tinned product is less than 2 µm, the width of the convexity-concavity (irregularity) of the surface of the tinned product is too narrow. When a lubricant is applied to such a surface to form the lubricant layer 16, it is not possible to apply the lubricant continuously in the recessed areas of the surface, so the holding force of the lubricant layer 16 is weak. For this reason, it is not possible to sufficiently maintain the effect of suppressing the oxidation of the abrasive powder due to microscopic sliding wear, so the resistance to microscopic sliding wear is slightly impaired.If, on the other hand, the mean rough curve element length RSm of the outermost surface of the tinned product exceeds 7 µm, the width of the convexity-concavity (irregularity) of the surface of the tinned product is too large, so that a difference between the strong and weak sections of the holding force of the lubricant layer 16 is easily caused. In the weak section of the holding force, it is not possible to sufficiently maintain the effect of suppressing the oxidation of the abrasive powder due to minute sliding wear, so that the resistance to minute sliding wear is slightly impaired.

[0023] Furthermore, the thickness of the tin layer 14 is preferably 0.2 to 1.5 µm. If the outermost surface of the tinned product has a convexity-concavity (irregularity) of a predetermined size to increase the amount of lubricant that can be absorbed, it is possible to further improve the resistance to minute sliding wear of the tinned product after it has been held in a high-temperature environment.

[0024] In the process for producing a tinned product according to the present invention, a tinning layer with a thickness of 0.4 to 3 µm is applied to the surface of a base material made of copper or a copper alloy by electroplating at a current density of 5 to 13 A / dm². 2A tinning bath consisting of water, tin sulfate, sulfuric acid, and a surfactant is formed, and the surface of the tinning layer is dried. The dried surface of the tinning layer is then heated to melt the tin and subsequently cooled. This process results in a tin layer 14 on the outermost surface, exhibiting a structure obtained through solidification after melting, while a copper-tin alloy layer 12 is formed between the tin layer 14 and the base material 10. Furthermore, a non-ionic, anionic, or amphoteric surfactant can be used.

[0025] In this process for producing a tinned product, a lubricant is preferably applied to the tin layer 14 to form a lubricant layer 16. The lubricant can be a lubricant produced by mixing a base oil, such as a paraffinic mineral oil, a naphthenic mineral oil, or a synthetic oil, with any of several lubricant additives. Pressing oil used for pressing can be used as such a lubricant. If such a pressing oil is used, even if no other lubricant is applied, it can be used as is, without removing the pressing oil used to press the tinned product. The pressing oil can be applied to the tin layer 14 to form the lubricant layer 16.Once the pressing oil has been applied, the tinned product can be pressed as is (without using any other pressing oil), and it is not necessary to perform any cleaning after pressing.

[0026] The tinning bath is preferably an aqueous solution containing 60 to 80 g / l tin sulfate, 65 to 85 g / l sulfuric acid and 1 to 3 ml / l surfactant.

[0027] Before the tinning layer is formed on the base material 10, a nickel plating layer (or a nickel alloy electroplating layer) can be formed on the base material 10, and a copper plating layer can be formed on the nickel plating layer (or the nickel alloy electroplating layer), so that a nickel plating layer (or a nickel alloy electroplating layer) can be formed as an underlying layer between the base material 10 and the copper-tin alloy layer 12. Examples

[0028] Examples of a tinned product and a method for producing the same according to the present invention are described in detail below. [Example 1]

[0029] First, a conductive, rolled sheet of a Cu-Ni-Sn alloy (a copper alloy containing 1.0 wt% nickel, 0.9 wt% tin, 0.05 wt% phosphorus, and the remainder copper, with an arithmetic mean roughness Ra of 0.133 µm and a maximum height Ry of 1.042 µm) (NB-109-EH, manufactured by DOWA METALTECH CO., LTD.) measuring 50 mm × 50 mm × 0.25 mm was prepared as the base material (the material to be electroplated). The base material was then electrolytically degreased and subsequently washed with water. Finally, it was pickled and then washed with water.

[0030] Then, the pretreated base material and a tin electrode plate were used as a cathode and an anode, respectively, to heat the base material at a current density of 5 A / dm². 2 and electroplating at a liquid temperature of 25 °C for 45 seconds in an aqueous solution containing 70 g / l tin sulfate (SnSO4), 75 g / l sulfuric acid (H2SO4), and 2 g / l of a polyoxyethylene stearylamine (anionic surfactant, used as a surfactant) to form a tin layer on the base material. The thickness of the tin layer was measured using an X-ray fluorescence thickness gauge (SFT3300S, manufactured by Seiko Nanoscience Inc.) (within an analysis range of 0.5 mm ϕ over an analysis time of 15 seconds using an excitation method). The measured thickness of the tin layer was 1 µm.

[0031] After a tinned product produced by forming the tin layer on the base material was washed with water and dried, a reflow treatment (tin melting treatment) was performed. For this reflow treatment, a near-infrared heater (HYW-8N, manufactured by HYBEC CORPORATION, rated voltage = 100 V, rated power = 560 W) was used to heat the tinned product in the atmosphere for 11 seconds at a current of 10.8 A, set by a power controller (HYW-20CCR-α N, manufactured by HYBEC CORPORATION), to melt the surface of the tin layer. Immediately after the surface of the tin layer melted, the tinned product was immersed in a water tank at 20 °C to cool.

[0032] The outermost surface of the tinned product thus produced was observed at a magnification of 5,000 using a scanning ion microscope (SEM) mounted on a focused ion beam processing observation device (JIB-4000, manufactured by JEOL Ltd.). Furthermore, after carbon (C) had been deposited on the outermost surface of the tinned product to a thickness of approximately 1 µm, the product was sectioned with a focused ion beam (FIB) using the focused ion beam processing observation device described above to expose a cross-section perpendicular to the rolling direction of the base material. The exposed cross-section was then observed at a magnification of 10,000 using the scanning ion microscope (SEM) described above. The surface and cross-section of the tinned product were thus observed to obtain SEM images.The SEM images of the surface and cross-section of the tin-plated product confirmed that the outermost layer was pure tin, and that a copper-tin alloy layer approximately 0.6 µm thick formed on its underside (on the base material side). The thickness of the pure tin layer and the copper-tin alloy layer were measured using an electrolytic film thickness gauge (TH11, manufactured by CHUO SEISA-KUSHO LTD.) according to the JIS H8501 electrolytic test procedure. The result showed a thickness of 0.5 µm for the pure tin layer.

[0033] The surface roughness of the tinned product thus produced was calculated as follows: the arithmetic mean roughness Ra and the maximum height Ry, which were parameters showing the surface roughness based on ISO4287-1997, were calculated from the results of measurements using a contact surface roughness measuring device (Surfcoder SE4000, manufactured by Kosaka Laboratory Ltd.); and the mean rough curve element length RSm (the mean length RSm of a rough curve element), the mean height Rc, and the oil reservoir depth Rvk (the depth of a groove part offset by an effective loading roughness of an oil reservoir), which were parameters showing the surface roughness Rk based on JIS B0601 (2001), were calculated from the results of measurements using a laser microscope (Laser Microscope VK-X100, manufactured by Keyence Corporation). As a result, the arithmetic mean roughness Ra was 0.166 µm and the maximum height Ry was 1.125 µm.The mean rough curve element length RSm was 3.48 µm, the mean height Rc was 0.66 µm, and the oil storage depth Rvk was 0.12 µm.

[0034] The gloss of the tinned product was measured parallel to the rolling direction of the base material using a densitometer (ND-1 densitometer, manufactured by NIPPON DENSHOKU INDUSTRIES CO., LTD.). The resulting gloss was 0.42.

[0035] The base material (material to be plated) is a Cu-Ni-Sn alloy (NB-109-EH, manufactured by DOWA METALTECH CO., LTD.) with a thickness of 0.25 mm and a width of 250 mm. The base material was then plated at a current density of 9 A / dm². 2The material was electroplated in a tinning bath containing an aqueous solution of 70 g / l tin sulfate (SnSO4), 75 g / l sulfuric acid (H2SO4), 30 g / l cresolsulfonic acid (as a leveling agent), and 2 g / l polyoxyethylene stearylamine (anionic surfactant) using a continuous reel-to-reel electroplating line to form a 1 µm thick tin layer on the base material, thus producing a tinned product. Subsequently, a reflow treatment was performed, in which the tinned product was immersed in a water tank at 20 °C for cooling immediately after the surface of the tin layer had been melted by heating it to 700 °C for 6.5 seconds, to produce a reflow-treated, tinned product.

[0036] Then, a test piece cut from the reflow-treated, tinned product was used as a plate test piece (a test piece serving as a plug connector). Additionally, 0.3 mg / cm² was measured. 2A chlorine-free, low-viscosity pressing oil (Unipress PA5, manufactured by JX Nippon Oil & Energy Corporation), serving as a lubricant (for plastic processing such as pressing or cutting), was applied to the surface of the tinned product produced in this embodiment. Subsequently, a test piece cut from the tinned product, onto which the lubricant had been applied, was pressed in (embossed in a hemispherical shape with R=1 mm) to serve as a pressed-in test piece (a test piece serving as a bushing connection). After the pressed-in test piece and the plate test piece were held at atmospheric temperature (ETTAS OF450, manufactured by AS ONE Corporation) at 120 °C for 120 hours, the pressed-in test piece and the plate test piece were removed.The plate specimen was then mounted on the table of a precision sliding test fixture (type CRS-G2050-DWA, manufactured by Yamasaki-Seiki Co., Ltd.), and the indentation of the indented specimen was brought into contact with the surface of the plate specimen. A sliding test was then performed in which the table supporting the plate specimen was moved back and forth horizontally at a sliding rate of one movement per second within a range of 50 µm in one direction, while the indented specimen was pressed against the surface of the slotted plate specimen with a load of 0.7 N. As a result, the base material was not exposed even after the specimen was moved back and forth 1000 times.Thus, it was found that the tinned product manufactured in this embodiment exhibits excellent resistance to minute sliding wear. [Example 2]

[0037] A tinned product was produced using the same method as in Example 1, except that the tinning layer was applied by electroplating at a current density of 10 A / dm². 2 The tinning layer was formed for 21 seconds. Furthermore, the thickness of the tinning layer was measured using the same method as in Example 1. The result was a tinning layer thickness of 1 µm.

[0038] Regarding the tin-plated product thus produced, its surface and cross-section were examined using the same procedure as in Example 1. The results confirmed that the outermost layer was a pure tin layer, and that a copper-tin alloy layer had formed on its underside (on the base material side). The SEM images of the surface and cross-section of this tin-plated product are shown in the Fig. 2 and 3 are shown. Furthermore, regarding layers above and below the dotted line in Fig.3. The layer above the dotted line is a layer (protective film) of carbon that was deposited when the tinned product was cut off, and the layer below the dotted line is the pure layer. The thickness of the pure tin layer and the thickness of the copper-tin alloy layer were measured using the same procedure as in Example 1. As a result, the thickness of the pure tin layer was 0.5 µm, and the thickness of the copper-tin alloy layer was approximately 0.6 µm. The arithmetic mean roughness Ra, the maximum height Ry, the mean rough curve element length RSm, the mean height Rc, and the oil storage depth Rvk were calculated using the same procedures as in Example 1. As a result, the arithmetic mean roughness Ra was 0.104 µm, and the maximum height Ry was 0.622 µm. The mean rough curve element length RSm was 2.13 µm, the mean height Rc was 0.16 µm, and the oil storage depth Rvk was 0.06 µm.The gloss of the tinned product was measured using the same method as in Example 1. The result was a gloss of 0.52. The sliding test was also performed using the same method as in Example 1. The result was that the base material was not exposed, even after the test piece was moved back and forth 1000 times. Thus, the tinned product manufactured in this embodiment was found to have excellent resistance to minute sliding wear. [Example 3]

[0039] A tinned product was produced using the same method as in Example 1, except that the tinning layer was applied by electroplating at a current density of 12 A / dm². 2 The tinning layer was formed for 18 seconds. Furthermore, the thickness of the tinning layer was measured using the same method as in Example 1. The result was a tinning layer thickness of 1 µm.

[0040] Regarding the tin-plated product thus produced, its surface and cross-section were examined using the same procedure as in Example 1. The results confirmed that the outermost layer was a pure tin layer and that a copper-tin alloy layer had formed on its underside (on the base material side). The thickness of the pure tin layer and the copper-tin alloy layer were measured using the same procedure as in Example 1. The thickness of the pure tin layer was found to be 0.5 µm, and the thickness of the copper-tin alloy layer was approximately 0.6 µm. The arithmetic mean roughness Ra, the maximum height Ry, the mean rough curve element length RSm, the mean height Rc, and the oil storage depth Rvk were calculated using the same procedures as in Example 1.As a result, the arithmetic mean roughness Ra was 0.092 µm, and the maximum height Ry was 0.786 µm. The mean rough curve element length RSm was 2.33 µm, the mean height Rc was 0.13 µm, and the oil retention depth Rvk was 0.04 µm. The gloss of the tinned product was measured using the same method as in Example 1. The result was a gloss of 0.59. The sliding test was performed using the same method as in Example 1. As a result, the base material was not exposed even after the test piece was moved back and forth 1000 times. Thus, it was found that the tinned product produced in this embodiment exhibits excellent resistance to minute sliding wear. [Example 4]

[0041] A tinned product was manufactured using the same procedure as in Example 1, except that the tinning layer was formed by electroplating for 20 seconds. Furthermore, the thickness of the tinning layer was measured using the same procedure as in Example 1. The result was a tinning layer thickness of 0.5 µm.

[0042] Regarding the tin-plated product thus produced, its surface and cross-section were examined using the same procedure as in Example 1. The results confirmed that the outermost layer was a pure tin layer, and that a copper-tin alloy layer formed on its underside (on the base material side). The thickness of the pure tin layer and the copper-tin alloy layer were measured using the same procedure as in Example 1. The thickness of the pure tin layer was found to be 0.2 µm, and the thickness of the copper-tin alloy layer was approximately 0.5 µm. The arithmetic mean roughness Ra, the maximum height Ry, the mean rough curve element length RSm, the mean height Rc, and the oil storage depth Rvk were calculated using the same procedures as in Example 1. As a result, the arithmetic mean roughness Ra was 0.176 µm, and the maximum height Ry was 1.336 µm.The mean rough curve element length RSm was 4.86 µm, the mean height Rc was 0.30 µm, and the oil retention depth Rvk was 0.15 µm. The gloss of the tinned product was measured using the same method as in Example 1. The result was a gloss of 0.31. The sliding test was performed using the same method as in Example 1. The result was that the base material was not exposed, even after the test piece was moved back and forth 1000 times. Thus, the tinned product produced in this embodiment was found to have excellent resistance to minute sliding wear. [Example 5]

[0043] The same base material was prepared as in Example 1. The base material was then electrolytically degreased as a pretreatment and subsequently washed with water. Following this, the base material was pickled and then washed with water.

[0044] Then the pretreated base material (the material to be electroplated) and a nickel electrode plate were used as a cathode and an anode, respectively, to electroplate the base material at a current density of 4 A / dm². 2 and electroplating at a liquid temperature of 50 °C for 40 seconds at 50 °C in a nickel plating solution containing 80 ml / l nickel sulfamate and 45 g / l boric acid to form a nickel plating layer on the base material.

[0045] Then, the base material was nickel-plated, and a copper electrode plate was used as a cathode and an anode, respectively, to charge the material at a current density of 4 A / dm². 2 and to electroplate at a liquid temperature of 25 °C for 50 seconds in a copper plating solution containing 110 g / l copper sulfate and 100 ml / l sulfuric acid to form a copper layer on the nickel plating layer.

[0046] A tinning layer was then formed on the copper plating layer to produce a tinned product using the same procedure as in Example 1, except that the tinning layer was formed by electroplating for 30 seconds. Furthermore, the thickness of each of the nickel plating, copper plating, and tinning layers was measured using the same procedure as in Example 1 for measuring the tinning layer. As a result, the thickness of the nickel plating layer was 0.3 µm, the thickness of the copper plating layer was 0.3 µm, and the thickness of the tinning layer was 0.7 µm.

[0047] Regarding the tin-plated product thus produced, its surface and cross-section were examined using the same procedure as in Example 1. The results confirmed that the outermost layer was a pure tin layer, and that a copper-tin alloy layer formed on its underside (on the base material side). The thickness of the pure tin layer and the copper-tin alloy layer were measured using the same procedure as in Example 1. The thickness of the pure tin layer was found to be 0.3 µm, and the thickness of the copper-tin alloy layer was approximately 0.6 µm. The arithmetic mean roughness Ra, the maximum height Ry, the mean rough curve element length RSm, the mean height Rc, and the oil storage depth Rvk were calculated using the same procedures as in Example 1. As a result, the arithmetic mean roughness Ra was 0.126 µm and the maximum height Ry was 0.964 µm.The mean rough curve element length RSm was 5.31 µm, the mean height Rc was 0.49 µm, and the oil retention depth Rvk was 0.08 µm. The gloss of the tinned product was measured using the same method as in Example 1. The result was a gloss of 0.45. The sliding test was performed using the same method as in Example 1. The result was that the base material was not exposed, even after the test piece was moved back and forth 1000 times. Thus, the tinned product produced in this embodiment was found to have excellent resistance to minute sliding wear. [Example 6]

[0048] A tinned product was manufactured using the same procedure as in Example 1, except that the tinning layer was formed by electroplating for 100 seconds. Furthermore, the thickness of the tinning layer was measured using the same procedure as in Example 1. The result was a tinning layer thickness of 2.3 µm.

[0049] Regarding the tin-plated product thus produced, its surface and cross-section were examined using the same procedure as in Example 1. The results confirmed that the outermost layer was a pure tin layer, and that a copper-tin alloy layer formed on its underside (on the base material side). The thickness of the pure tin layer and the copper-tin alloy layer were measured using the same procedure as in Example 1. The results showed that the pure tin layer was 1.5 µm thick, and the copper-tin alloy layer was approximately 0.6 µm thick. The arithmetic mean roughness Ra, the maximum height Ry, the mean rough curve element length RSm, the mean height Rc, and the oil storage depth Rvk were calculated using the same procedures as in Example 1. As a result, the arithmetic mean roughness Ra was 0.157 µm, and the maximum height Ry was 1.147 µm.The mean rough curve element length RSm was 4.40 µm, the mean height Rc was 0.56 µm, and the oil retention depth Rvk was 0.09 µm. The gloss of the tinned product was measured using the same method as in Example 1. The result was a gloss of 0.69. The sliding test was performed using the same method as in Example 1. The result was that the base material was not exposed, even after the test piece was moved back and forth 1000 times. Thus, the tinned product produced in this embodiment was found to have excellent resistance to minute sliding wear. [Comparison example 1]

[0050] First, a Cu-Ni-Sn alloy (NB-109-EH, manufactured by DOWA METALTECH CO., LTD.) with a thickness of 0.25 mm and a width of 250 mm was prepared as the base material (material to be electroplated). Then, a tinned product was manufactured using the same process as in Example 1, except that a tinning layer was applied by electroplating at a current density of 9 A / dm². 2 Tinning was carried out in a tinning bath containing an aqueous solution of 70 g / l tin sulfate (SnSO4), 75 g / l sulfuric acid (H2SO4), 30 g / l cresolsulfonic acid (serving as a leveling agent), and 2 g / l polyoxyethylene stearylamine (anionic surfactant, serving as a surfactant) using a continuous reel-to-reel electroplating line. The thickness of the tinning layer was then measured using the same method as in Example 1. The result was a tinning layer thickness of 1 µm.

[0051] Regarding the tin-plated product thus produced, its surface and cross-section were examined using the same procedure as in Example 1. The results confirmed that the outermost layer was a pure tin layer, and that a copper-tin alloy layer formed on its underside (on the base material side). The thickness of the pure tin layer and the copper-tin alloy layer were measured using the same procedure as in Example 1. The thickness of the pure tin layer was found to be 0.6 µm, and the thickness of the copper-tin alloy layer was approximately 0.5 µm. The arithmetic mean roughness Ra, the maximum height Ry, the mean rough curve element length RSm, the mean height Rc, and the oil storage depth Rvk were calculated using the same procedures as in Example 1. As a result, the arithmetic mean roughness Ra was 0.021 µm, and the maximum height Ry was 0.300 µm.The mean rough curve element length RSm was 1.90 µm, the mean height Rc was 0.02 µm, and the oil retention depth Rvk was 0.01 µm. The gloss of the tinned product was measured using the same procedure as in Example 1. The result was a gloss of 1.60. The sliding test was performed using the same procedure as in Example 1. The result was that the base material was exposed after the test piece was moved back and forth 143 times. Thus, the resistance to micro-sliding wear of the tinned product produced in this comparative embodiment was found to be poor. [Comparative example 2]

[0052] A tinned product was produced using the same method as in Example 1, except that the tinning layer was applied by electroplating at a current density of 4 A / dm². 2The tinning layer was formed for 55 seconds. Furthermore, the thickness of the tinning layer was measured using the same method as in Example 1. The result was a tinning layer thickness of 1 µm.

[0053] Regarding the tin-plated product thus produced, its surface and cross-section were examined using the same procedure as in Example 1. The results confirmed that the outermost layer was a pure tin layer, and that a copper-tin alloy layer formed on its underside (on the base material side). The thickness of the pure tin layer and the copper-tin alloy layer were measured using the same procedure as in Example 1. The thickness of the pure tin layer was found to be 0.5 µm, and the thickness of the copper-tin alloy layer was approximately 0.6 µm. The arithmetic mean roughness Ra, the maximum height Ry, the mean rough curve element length RSm, the mean height Rc, and the oil storage depth Rvk were calculated using the same procedures as in Example 1. As a result, the arithmetic mean roughness Ra was 0.379 µm, and the maximum height Ry was 2.743 µm.The mean rough curve element length RSm was 7.43 µm, the mean height Rc was 1.66 µm, and the oil retention depth Rvk was 0.26 µm. The gloss of the tinned product was measured using the same procedure as in Example 1. The result was a gloss of 0.22. The sliding test was performed using the same procedure as in Example 1. The result was that the base material was exposed after the test piece was moved back and forth 373 times. Thus, the resistance to micro-sliding wear of the tinned product produced in this comparative embodiment was found to be poor. [Comparative example 3]

[0054] A tinned product was produced using the same method as in Example 1, except that the tinning layer was applied by electroplating at a current density of 14 A / dm². 2The tinning layer was formed for 15 seconds. Furthermore, the thickness of the tinning layer was measured using the same method as in Example 1. The result was a tinning layer thickness of 1 µm.

[0055] Regarding the tin-plated product thus produced, its surface and cross-section were examined using the same procedure as in Example 1. The results confirmed that the outermost layer was a pure tin layer, and that a copper-tin alloy layer formed on its underside (on the base material side). The thickness of the pure tin layer and the copper-tin alloy layer were measured using the same procedure as in Example 1. The thickness of the pure tin layer was found to be 0.5 µm, and the thickness of the copper-tin alloy layer was approximately 0.6 µm. The arithmetic mean roughness Ra, the maximum height Ry, the mean rough curve element length RSm, the mean height Rc, and the oil storage depth Rvk were calculated using the same procedures as in Example 1. As a result, the arithmetic mean roughness Ra was 0.091 µm, and the maximum height Ry was 0.743 µm.The mean rough curve element length RSm was 1.53 µm, the mean height Rc was 0.03 µm, and the oil retention depth Rvk was 0.01 µm. The gloss of the tinned product was measured using the same procedure as in Example 1. The result was a gloss of 0.72. The sliding test was performed using the same procedure as in Example 1. The result was that the base material was exposed after the test piece was moved back and forth 605 times. Thus, the resistance to micro-sliding wear of the tinned product produced in this comparative embodiment was found to be poor. [Comparative example 4]

[0056] A tinned product was manufactured using the same procedure as in Example 1, except that the tinning layer was formed by electroplating for 15 seconds. Furthermore, the thickness of the tinning layer was measured using the same procedure as in Example 1. The result was a tinning layer thickness of 0.3 µm.

[0057] Regarding the tin-plated product thus produced, its surface and cross-section were examined using the same procedure as in Example 1. The results confirmed that the outermost layer was a pure tin layer, and that a copper-tin alloy layer formed on its underside (on the base material side). The thickness of the pure tin layer and the copper-tin alloy layer were measured using the same procedure as in Example 1. The thickness of the pure tin layer was found to be 0.1 µm, and the thickness of the copper-tin alloy layer was approximately 0.3 µm. The arithmetic mean roughness Ra, the maximum height Ry, the mean rough curve element length RSm, the mean height Rc, and the oil storage depth Rvk were calculated using the same procedures as in Example 1. As a result, the arithmetic mean roughness Ra was 0.186 µm, and the maximum height Ry was 1.447 µm.The mean rough curve element length RSm was 6.72 µm, the mean height Rc was 1.02 µm, and the oil retention depth Rvk was 0.12 µm. The gloss of the tinned product was measured using the same procedure as in Example 1. The result was a gloss of 0.20. The sliding test was performed using the same procedure as in Example 1. As a result, the base material was exposed after the test piece was moved back and forth 161 times. Thus, it was found that the resistance to micro-sliding wear of the tinned product produced in this comparative embodiment was not good. [Comparative example 5]

[0058] A tin-plated product was manufactured using the same procedure as in Example 1, except that the tinning layer was formed by electroplating for 100 seconds. Furthermore, the thickness of the tinning layer was measured using the same procedure as in Example 1. The result was a tinning layer thickness of 3.2 µm.

[0059] Regarding the tin-plated product thus produced, its surface and cross-section were examined using the same procedure as in Example 1. The results confirmed that the outermost layer was a pure tin layer, and that a copper-tin alloy layer formed on its underside (on the base material side). The thickness of the pure tin layer and the copper-tin alloy layer were measured using the same procedure as in Example 1. The thickness of the pure tin layer was found to be 2.3 µm, and the thickness of the copper-tin alloy layer was approximately 0.6 µm. The arithmetic mean roughness Ra, the maximum height Ry, the mean rough curve element length RSm, the mean height Rc, and the oil storage depth Rvk were calculated using the same procedures as in Example 1. As a result, the arithmetic mean roughness Ra was 0.209 µm, and the maximum height Ry was 1.930 µm.The mean rough curve element length RSm was 1.90 µm, the mean height Rc was 0.02 µm, and the oil retention depth Rvk was 0.01 µm. The gloss of the tinned product was measured using the same method as in Example 1. The result was a gloss of 0.71. The sliding test was performed using the same method as in Example 1. The result was that the base material was exposed when the test piece was moved back and forth 1000 times. Thus, it was found that the resistance to micro-sliding wear of the tinned product produced in this comparative embodiment was not good.

[0060] The manufacturing conditions and key figures for the tinned products in these examples and comparison examples are given in Tables 1 and 2. Table 1 tinning Thickness (µm) Current density (A / dm³) 2 ) Leveler Example 1 1 5 - Example 2 1 10 - Example 3 1 12 - Example 4 0,5 5 - Example 5 0,7 5 - Example 6 2,3 5 - See 1 1 9 Cresolsulfonic acid See 2 1 4 - See 3 1 14 - See 4 0,3 5 - See 5 3,2 5 - Table 2 Sn thickness (µm) Surface roughness (µm) shine Number of sliding processes at the time of exposure of the base material Ra Ry RSm RC Rvk Example 1 0,5 0,166 1,125 3,48 0,66 0,12 0,42 > 1000 Example 2 0,5 0,104 0,662 2,13 0,16 0,06 0,52 > 1000 Example 3 0,5 0,092 0,786 2,33 0,13 0,04 0,59 > 1000 Example 4 0,2 0,176 1,336 4,86 0,30 0,15 0,31 > 1000 Example 5 0,3 0,126 0,964 5,31 0,49 0,08 0,45 > 1000 Example 6 1,5 0,157 1,147 4,40 0,56 0,09 0,69 > 1000 See 1 0,6 0,021 0,300 1,90 0,02 0,01 1,60 143 See 2 0,5 0,379 2,743 7,43 1,66 0,26 0,22 373 See 3 0,5 0,091 0,743 1,53 0,03 0,01 0,72 605 See 4 0,1 0,186 1,447 6,72 1,02 0,13 0,20 161 See 5 2,3 0,209 1,930 1,90 0,02 0,01 0,71 < 1000 Description of the reference numbers 10 Basic materials 12 copper-tin alloy layer 14 tin layer 16 Lubricant layer

Claims

[1] Tinned product comprising: a base material (10) made of copper or a copper alloy; a copper-tin alloy layer (12) formed on the base material (10), and a tin layer (14) formed on the copper-tin alloy layer (12), wherein the tinned product has a luster of 0.3 to 0.7 and the outermost surface of the tinned product has a mean height Rc of 0.1 to 1.0 µm. [2] Tinned product according to claim 1, wherein the tin layer (14) has a structure obtained by solidification after melting. [3] Tinned product according to claim 1, wherein the outermost surface of the tinned product has an arithmetic mean roughness Ra of 0.05 to 0.20 µm. [4] Tinned product according to claim 1, wherein the outermost surface of the tinned product has an oil storage depth Rvk of 0.03 to 0.20 µm. [5] Tinned product according to claim 1, wherein the outermost surface of the tinned product has a mean rough curve element length RSm of 2 to 7 µm. [6] Tin-plated product according to claim 1, which further comprises a nickel layer or a nickel alloy layer, wherein the nickel layer or the nickel alloy layer is formed between the base material (10) and the copper-tin alloy layer (12). [7] Tinned product according to claim 1, which further comprises a lubricant layer (16) formed on the tin layer (14). [8] Tinned product according to claim 1, wherein the tin layer (14) is formed on the entire surface of the copper-tin alloy layer (12). [9] Method for producing a tinned product, the method comprising the steps of: a tinning layer with a thickness of 0.4 to 3 µm on the surface of a base material (10) made of copper or a copper alloy by electroplating at a current density of 5 to 13 A / dm² 2 is formed in a tinning bath consisting of water, tin sulfate, sulfuric acid and a surfactant; the surface of the tinning layer is dried; the dried surface of the tinning layer is heated to melt the tin; and the heated surface of the tinning layer is cooled to cause a layer of the tinning layer on the side of the outermost surface to be a tin layer having a structure obtained by solidification after melting, while causing a layer of the tinning layer between the tin layer and the base material (10) to be a copper-tin alloy layer. [10] Method for producing a tinned product according to claim 9, which further comprises a step for applying a lubricant to the tin layer in order to form a lubricant layer (16) thereon. [11] Use of a tinned product according to claim 1 as a material in a connector. [12] Method for manufacturing an insertable and extendable terminal block, the method comprising the steps of: a product produced by a method for producing a tinned product according to claim 10; and A pressing process is carried out on the tinned product to produce a usable and extendable terminal block.

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