JP2014162943A - Automotive terminal material and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automotive terminal material having excellent bendability and weldability by achieving the optimization of an Ni plating film as base plating formed on a brass sheet, and a method for producing the same.SOLUTION: The automotive terminal material is composed of composite layer plating in which the surface of a brass sheet 2 is provided with: an Ni plating film 3 as base plating; a Cu plating film 6 as intermediate plating; and an Sn plating film 7 as surface layer plating, where the Ni plating film 3 is formed by alternately laminating at least one glossy Ni plating layer 4 and at least one dull Ni plating layer 5 one by one.

Description

  The present invention relates to an automobile terminal material having a Ni plating film as a base plating, a Cu plating film as an intermediate plating, and an Sn plating film as a surface layer plating on a brass plate and excellent in bending workability and weldability.

  In order to impart or improve desired physical properties such as surface hardness, corrosion resistance, heat resistance, conductivity, weldability, etc. in addition to the properties of the metal material itself, the surface of the metal substrate is usually made of metal. In many cases, a plating film having a composition different from that of the base material is formed and used as a plating material. Such a plating material is widely used in a wide range of technical fields such as can materials, electrical products, and electronic parts such as terminals and connectors. Has been.

  Among these, terminals, particularly automobile terminals used in vehicles such as automobiles, are described in Patent Documents 1 and 2, for example, Ni as a base plating layer on a copper alloy substrate such as brass. In general, it is generally manufactured from a plating material obtained by forming a layer, a Cu layer as an intermediate plating layer, and an Sn layer as a surface plating layer in order, and then performing a reflow treatment.

  In addition, recently, from the viewpoint of reducing the size of the terminal due to the narrowing of the space in the automobile and improving the durability of the connection structure formed by the wire conductor and the terminal, the automobile terminal has a predetermined plate shape. The plated material is punched into a cylindrical shape, the connector is formed, and the tubular crimped portion is temporarily formed. Then, both ends of the bent plated material are laser welded to form a tubular shape Attempts are being made to form a crimped part.

  This automobile terminal can form a connection structure having a sealed structure by inserting the conductor exposed portion of the electric wire into the cylindrical crimped portion and crimping, and moisture does not easily enter the sealed structure. So-called dissimilar metal corrosion can be suppressed between the electric wire conductor and the terminal, and there is an advantage that stable electric conduction can be ensured between the electric wire conductor and the terminal for a long period of time.

  From the viewpoint of weight reduction, an automobile terminal capable of forming a connection structure having such a sealed structure is connected to an electric wire using an electric wire made of aluminum or an aluminum alloy (hereinafter simply referred to as “aluminum electric wire”). When a structure is formed, it is particularly preferable in that corrosion between different metals can be suppressed.

  Moreover, as a base material of the plating material used for the automobile terminal, it is preferable to use a brass base material from the viewpoint of strength and cost.

  However, as described above, the terminal having the tubular crimping portion is bent from a plate-like plating material into a cylindrical shape and then laser-welded, so that it occurs during severe bending conditions and laser welding. Therefore, it is necessary to use a plating material that can withstand both of the welding heat.

  At this time, when laser welding is performed to form a tubular crimping portion of a terminal using a conventional plating material having a plating layer structure as described in Patent Documents 1 and 2, the copper in the copper alloy base material is There is a tendency that heat welding diffuses into the Sn plating layer of the surface plating due to welding heat, and as a result of the formation of the Sn-Cu alloy layer in the Sn plating layer, there is a problem that the electrical contact resistance increases.

In addition, when the copper alloy base material is a brass base material, as described in Non-Patent Documents 1 and 2, the brass base material in which zinc in the brass base material is easily evaporated by welding heat and zinc is evaporated. There was also a problem that the weldability of the steel deteriorated. When brass is melted, a temperature of about 1000 ° C. is required, whereas the boiling point of Zn contained in a large amount of brass is about 907 ° C. under one atmospheric pressure. And volume expansion. As a result, when the brass material is laser-welded, there arises a problem that a lot of welding defects such as a large amount of blowholes, a rough weld surface, and cracks occur.

  As a conventional means for suppressing heat diffusion and evaporation of components in the copper alloy base material due to welding heat, for example, it is useful to form a nickel plating film as a base plating as thick as 1 μm or more. .

  However, a normal Ni plating film has a high internal stress in the film and a high film hardness. Therefore, when a Ni plating film with a thickness exceeding 1 μm is formed on a copper alloy substrate, the Ni plating film is formed during bending. There is a problem that cracks are likely to occur, and in some cases there is a possibility that cracks generated in the plating film may propagate to the base material, especially in the case of severe bending conditions as described above, Conceivable.

  Patent Documents 1 and 2 do not describe the thermal diffusion and evaporation of components in a copper alloy base material, particularly a brass base material, which accompanies welding heat, and the thickness of each Ni plating film is 1 μm or less. Therefore, it is not possible to sufficiently suppress the components in the copper alloy base material from being thermally diffused and evaporated by welding heat.

JP 2003-171790 A JP 2004-68026 A

Yasuhiro Nishio and two others, “Welding of copper and copper alloys”, Journal of the Japan Welding Society, Japan Welding Society, 1969, Vol. 38, No. 9, p. 18-27 “Basics and Industrial Technology of Copper and Copper Alloys (Revised Version)”, Japan Copper and Brass Association, 1994, p. 358

  An object of the present invention is to provide an automobile terminal material excellent in bending workability and weldability by providing an appropriate Ni plating film as a base plating formed on a brass plate, and a method for producing the same.

In order to achieve the above object, the gist of the present invention is as follows.
(1) In an automobile terminal material having a Ni plating film as a base plating, a Cu plating film as an intermediate plating, and a Sn plating film as a surface plating on a brass plate, the Ni plating film has at least one layer of bright Ni An automotive terminal material comprising a multilayer plating formed by alternately laminating a plating layer and at least one matte Ni plating layer one by one.

(2) The plating according to the above (1), wherein the ratio of the thickness of the bright plating layer to the matte plating layer constituting the multilayer plating is in the range of 0.1 to 10 in comparison with each layer. material.

(3) The bright plating layer and the matte plating layer constituting the multilayer plating each have a thickness of 1 μm or less per layer, and the thickness of the multilayer plating exceeds 1 μm. The plating material as described in 1) or (2).

(4) The above (1), (2) or (3), wherein the Ni plating film is composed of a multi-layer plating of one bright plating layer and one non-gloss plating layer located on the bright plating layer. Automotive terminal materials described in 1.

(5) The above (1), (2) or (3), wherein the Ni plating film is composed of a multi-layer plating of one matte plating layer and one glossy plating layer located on the matte plating layer. Automotive terminal materials described in).

(6) In a method for manufacturing an automobile terminal material, comprising a step of sequentially forming a Ni plating film as a base plating, a Cu plating film as an intermediate plating, and a Sn plating film as a surface plating on a brass plate, the Ni plating film Is formed as a multi-layer plating by alternately laminating at least one glossy Ni plating layer and at least one matte Ni plating layer one by one, and then by the electrodeposition method, A method for producing an automobile terminal material, comprising sequentially forming a Cu plating film and a Sn plating film and then performing a reflow treatment.

  According to the present invention, it is possible to provide an automobile terminal material excellent in bending workability and weldability and a manufacturing method thereof by optimizing a Ni plating film as a base plating formed on a brass plate. became.

FIG. 1 is a cross-sectional view of a typical plating material according to the present invention. FIG. 2 is a cross-sectional view of another plating material of the present invention. FIG. 3 is a cross-sectional view of another plating material of the present invention. FIG. 4 is a cross-sectional view of another plating material of the present invention.

Next, embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 schematically shows a cross-sectional configuration of a typical automobile terminal material according to the present invention. An automobile terminal material 1 shown in FIG. 1 sequentially forms a Ni plating film 3 as a base plating, a Cu plating film 6 as an intermediate plating, and an Sn plating film 7 as a surface plating on a brass plate 2 as a base material. It has become the composition.

  The reason why the base material of the automobile terminal material is limited to brass is that it is excellent in cost. Particularly, since the zinc content is contained in a large amount of about 30% by mass, the brass plate is generated by the welding heat accompanying laser welding. This is because the effect of improving laser weldability is remarkably recognized because zinc is easily evaporated from the inside.

  The main feature of the configuration of the present invention is to optimize the Ni plating film 3 as the base plating formed on the brass plate 2, more specifically, the Ni plating film 3 has at least one layer. Of the Ni plating layer 4 and the at least one non-glossy Ni plating layer 5 are formed by alternately laminating one layer at a time. The bending workability and weldability of the material 1 can be satisfied at a high level.

  That is, the inventors suppress the crimping of the terminal by bending workability under severe conditions, thermal diffusion of the copper component in the brass plate 2 due to welding heat during laser welding, and evaporation of the zinc component. As a result of earnestly examining means for satisfying both of the laser weldability by the high level, unexpectedly, the Ni plating film 3 as the base plating is formed with a relatively hard glossy Ni plating layer 4 having a high internal stress. When the multi-layer Ni plating is formed by laminating the relatively soft matte Ni plating layer 5 having a low internal stress, the overall internal stress of the Ni plating film 3 decreases with time, and the Ni plating film 3 is hardened. Has been found to decrease significantly.

  For this reason, in the automobile terminal 1 of the present invention, the thickness of the Ni plating film 3 exceeds 1 μm by forming the Ni plating film 3 made of the multilayer Ni plating as the base plating on the brass plate 2. In addition, good bending workability is obtained, and the Ni plating film 3 is formed thick, so that it is effective for the thermal diffusion of the copper component in the brass plate by the welding heat during laser welding and the evaporation of the zinc component. As a result, it has succeeded in satisfying both bending workability and weldability at a high level.

  In addition, although it is not certain about the mechanism in which the overall internal stress of the Ni plating film 3 constituting the automobile terminal material 1 of the present invention decreases with time, the bright Ni plating layer 4 having a high internal stress and the internal stress is low. By laminating the matte Ni plating layer 5 so as to be in contact with each other at the interface between them, recrystallized grains are generated at the boundary of the plated layer, and eventually the Ni plating crystal grains with low internal stress are formed. It is estimated to be.

  The mechanism by which the zinc component in the brass plate 2 is prevented from evaporating due to the welding heat during laser welding by forming the Ni plating film 3 thick is probably because zinc in the brass plate 2 is contained in the Ni plating film 3. It is considered that the amount of Ni necessary for forming the compound with zinc is present by forming a compound with Ni and forming the Ni plating film 3 thick.

  Further, when the Ni plating film 3 is formed as a multilayer Ni plating by laminating the bright Ni plating layer 4 and the matte Ni plating layer 5, the hardness of the Ni plating film 3 is a relatively hard glossy Ni plating. It has also been found that it does not fall between the hardness of the layer 4 and the hardness of the relatively soft matte Ni plating layer 5 and is surprisingly even smaller than the hardness of the matte Ni plating layer 5. For example, the Knoop hardness HK of the Ni plating film 3 constituting the automobile terminal material 1 is preferably 250 or less, and more preferably in the range of 100 to 200. In addition, the measurement of Knoop hardness was performed based on "Knoop hardness test-test method" prescribed | regulated to JISZ2251: 2009, and test conditions were 5 gf and 15 seconds.

  In addition, regarding the distinction between the glossy Ni plating layer 4 and the matte Ni plating layer 5, for example, when these plating layers 4 and 5 are formed by an electrodeposition method, surface gloss is generated when the plating layer is formed. A plating layer formed by adding an additive such as a brightening agent to the plating bath composition is referred to as a bright Ni plating layer 4 and is formed without adding an additive for generating surface gloss to the plating bath composition. The plating layer was made the matte Ni plating layer 5 to distinguish them.

  Further, in the present invention, since the bright Ni plating layer 4 and the matte plating layer 5 constituting the Ni plating film 3 may be laminated so as to be in contact with each other, for example, the Ni plating film 3 is shown in FIG. 1, the order of lamination of the plating layers 4 and 5 is opposite, that is, the Ni plating film 3 is laminated in the order of the matte Ni plating layer 5 and the bright Ni plating layer 4 from the brass plate 2 side. It consists of a multilayer Ni plating of one glossy Ni plating layer 4 and one matte Ni plating layer 5, and, as shown in FIG. 3, from the brass plate 2 side, the glossy Ni plating layer 4a, It is composed of a multilayer Ni plating of two glossy Ni plating layers 4a and 4b and one matte Ni plating layer 5 laminated in the order of the bright Ni plating layer 5 and the bright Ni plating layer 4b, or FIG. As shown in FIG. 4, the plating film 3 is formed from the brass plate 2 side. Consists of a multilayer Ni plating of one glossy Ni plating layer and two matte Ni plating layers laminated in the order of the bright Ni plating layer 5a, the bright Ni plating layer 4 and the matte Ni plating layer 5b. Also good.

  In addition, the number of layers of the bright Ni plating layer 4 and the matte Ni plating layer 5 is different from that of each of the bright Ni plating layer 4 and the matte plating layer 5 from the viewpoint of effectively reducing the internal stress of the Ni plating film. Although it is preferable to reduce the thickness as much as possible to increase the number of arranged layers in order to promote the growth of recrystallization, the upper limit of the number of arranged layers is substantially limited from the viewpoint of manufacturing.

  In the present invention, the ratio of the thickness of the bright Ni plating layer 4 to the non-gloss Ni plating layer 5 constituting the multilayer Ni plating 3 is in the range of 0.1 to 10 in comparison with each layer. More preferably, it is 0.3-3, More preferably, it is 0.8-1.2. If the thickness ratio is out of the range of 0.1 to 10, either the bright Ni plating layer 4 or the matte Ni plating layer 5 becomes too thick, and thus occurs between these plating layers 4 and 5. This is because the recrystallized grains tend not to be generated up to the entire plating layer having a larger thickness, and the Ni plating film 3 tends not to be sufficiently soft.

  Furthermore, in the present invention, each of the bright Ni plating layer 4 and the matte Ni plating layer 5 constituting the multilayer Ni plating 3 has a thickness of 1 μm or less per layer, and the multilayer Ni plating 3 The thickness is preferably more than 1 μm. When the thickness per layer of one or both of the bright Ni plating layer 4 and the dull Ni plating layer 5 is more than 1 μm, the recrystallization generated between the plating layers 4 and 5 is a plating layer having a thickness exceeding 1 μm. This is because there is a tendency that the Ni plating film 3 cannot be made sufficiently soft. Moreover, when the thickness of the multilayer Ni plating 3 is 1 μm or less, good bending workability is obtained, but the copper component, which is a metal component in the brass plate 2, is thermally diffused into the Sn plating layer 7 during welding. This is because it may not be possible to sufficiently suppress the evaporation of the zinc component.

  The thickness of the underlying Ni plating layer is preferably in the range of 0.1 μm to 6.0 μm, more preferably 0.8 to 3.0 μm or less. If the Ni plating thickness is too thin, the effect of improving laser weldability cannot be obtained. If it is too thick, the amount of energy for welding the plating layer itself is required, so that laser weldability is reduced.

  Moreover, the automotive terminal material of the present invention has a Cu plating layer 6 as an intermediate plating, as shown in FIGS. 1 to 4 on the Ni plating film 3 because heat resistance and contact reliability are required. The Sn plating layer 7 as the surface layer plating is sequentially laminated.

  In the above-described embodiment, the case where the bright Ni plating layer 4 and the matte Ni plating layer 5 constituting the Ni plating film 3 are formed by the electrodeposition method has been described as an example. Other wet plating methods and dry plating methods such as vapor deposition can also be used.

Next, an example of the manufacturing method of the plating material of this invention is demonstrated below.
The manufacturing method of the automobile terminal material of the present invention is such that after degreasing and pickling are sequentially performed by a conventional method, at least one bright plating layer 4 and at least one layer are directly deposited on the brass plate 2 by electrodeposition. The matte plating layer 5 is formed by alternately laminating one layer at a time, and then, by forming both the Cu plating layer 6 and the Sn plating layer 7 in order by an electrodeposition method, by performing a reflow process, The automobile terminal material of the present invention can be manufactured.

  Table 1 shows, as an example, plating baths and plating conditions suitable for forming the bright Ni plating layer 4, the matte Ni plating layer 5, the Cu plating layer 6 and the Sn plating layer 7 constituting the automobile terminal material of the present invention. Shown in The thickness of the plating layer was adjusted according to the plating time. Confirmation of the thickness of the plating layer can be confirmed, for example, by measuring the fluorescent X-ray with a plating thickness analysis or the like.

  In addition, the place mentioned above only showed the example of embodiment of this invention, and can change a various change in a claim.

Next, an automobile terminal material according to the present invention was prototyped and performance evaluation was performed, which will be described below.
Inventive Examples 1 to 8 use brass having a thickness of 0.25 mm (manufactured by Furukawa Electric Co., Ltd., JIS C2600) as the metal substrate, and the plating bath composition and plating conditions shown in Table 1 are provided on this brass plate. Then, a plating film having a film structure shown in Table 2 was formed, and then a reflow treatment was performed under the conditions shown in Table 2 to produce a plating material.

  For comparison, a Ni-plated film was also prototyped for Comparative Examples 1 and 2 formed with one matte Ni-plated layer or one glossy Ni-plated layer, so performance was evaluated in the same manner as the inventive examples. .

  The performance evaluation of each prototype was performed for laser weldability.

(Performance evaluation)
-Laser weldability Each metal base material in which the plating film was formed was deformed into a cylindrical shape, and both ends thereof were laser-welded to form a cylindrical crimp portion of the terminal. A fiber laser (model number: ASF1J23, laser wavelength: 1084 nm) manufactured by Furukawa Electric Co., Ltd. was used as the laser. The laser beam output was fixed at 400 W, and laser weldability was evaluated at a speed at which penetration welding was possible. Here, from the relationship between speed and time, it can be considered that the speed is fast = the time is short = the amount of energy required for laser welding is small. Evaluation criteria were as follows: ◎: through welding at 400 mm / sec or more, ○: through welding at 300 mm / sec or more, ×: slower than 200 mm / sec.
The measurement conditions are as follows.
-Laser light source: Furukawa Electric 500W CW fiber laser ASF1J233 (wavelength 1084nm single mode oscillation laser light)
・ Laser light output: 400W
・ Sweep distance: 10mm
・ Laser beam irradiation with all conditions just focus (spot size: 0.02mm)

From the evaluation results shown in Table 2, Invention Examples 1 to 8 were all excellent in laser weldability and bending workability.
On the other hand, Comparative Examples 1 and 2 were inferior in laser weldability.

  According to the present invention, it is possible to provide an automobile terminal material excellent in bending workability and weldability and a manufacturing method thereof by optimizing a Ni plating film as a base plating formed on a brass plate. became.

1, 1A, 1B, 1C Automotive terminal material 2 Brass plate 3 Ni plating film (or Ni multilayer plating)
4, 4a, 4b Glossy Ni plating layer 5, 5a, 5b Matte Ni plating layer 6 Cu plating layer 7 Sn plating layer

Claims (6)

An automotive terminal material having a Ni plating film as a base plating, a Cu plating film as an intermediate plating, and a Sn plating film as a surface plating on a brass plate,
An automobile terminal material, wherein the Ni plating film comprises a multilayer plating formed by alternately laminating at least one glossy Ni plating layer and at least one matte Ni plating layer one by one .   2. The automobile terminal material according to claim 1, wherein the ratio of the thickness of the bright plating layer to the matte plating layer constituting the multilayer plating is in a range of 0.1 to 10 in comparison with each other.   3. The bright plating layer and the matte plating layer constituting the multilayer plating each have a thickness of 1 μm or less per layer, and the thickness of the multilayer plating exceeds 1 μm. Automotive terminal materials described in 1.   The automobile terminal material according to claim 1, 2 or 3, wherein the Ni plating film comprises a multilayer plating of one gloss plating layer and one matte plating layer located on the gloss plating layer.   4. The automobile terminal material according to claim 1, wherein the Ni plating film comprises a multilayer plating of one matte plating layer and one gloss plating layer located on the matte plating layer. A method of manufacturing an automobile terminal material including a step of sequentially forming a Ni plating film as a base plating, a Cu plating film as an intermediate plating, and a Sn plating film as a surface layer plating on a brass plate,
The Ni plating film is formed as a multilayer plating by alternately laminating at least one glossy Ni plating layer and at least one matte Ni plating layer one by one by an electrodeposition method, and then electrodeposition A method for producing an automobile terminal material, comprising sequentially forming a Cu plating film and a Sn plating film by a method and then performing a reflow treatment.

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