JP2019137894A - Corrosion preventing terminal material, method of producing the same, and corrosion preventing terminal - Google Patents

Abstract

To provide a terminal material that is hard to corrode electrically, has a good appearance, and enhances an adhesive property of a coating.SOLUTION: An corrosion preventing terminal material of this invention is stacked with a coating on a base material made of copper or copper alloy and, when molded to a terminal, is formed of a core-wire-contact-intended part that a core wire of an electric wire contacts and a contact-point-intended part which becomes a contact part. A coating to be formed on the core-wire-contact-intended part is stacked with a zinc nickel alloy layer including zinc and nickel, a tin layer made of tin or tin alloy, and a zinc metal layer in this order. A coating formed on the contact-point-intended part includes a tin layer on the base material. The zinc nickel alloy layer includes a tapered part where coating thickness becomes gradually smaller as approaching the contact-point-intended part in an edge part of the core-wire-contact-intended part adjacent to the contact-point-intended part and does not exist on a part of the contact-point-intended part that is beyond the tapered part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an anticorrosion terminal material that is used as a terminal to be crimped to an end of an electric wire made of an aluminum wire, and to a method for producing the same and an anticorrosion terminal.

Conventionally, by crimping a terminal made of copper or a copper alloy to the terminal portion of an electric wire made of copper or a copper alloy, and connecting the terminal to a terminal provided in the equipment, the electric wire is attached to the equipment. Connecting is done. Further, for the purpose of reducing the weight of the electric wire, the core of the electric wire may be made of aluminum or an aluminum alloy instead of copper or a copper alloy.
For example, Patent Document 1 discloses an aluminum wire for an automobile wire harness made of an aluminum alloy.

  By the way, when an electric wire (conductive wire) is made of aluminum or an aluminum alloy and a terminal is made of copper or a copper alloy, when water enters the crimping portion between the terminal and the electric wire, electrolytic corrosion due to a potential difference between different metals occurs. Sometimes. And with the corrosion of the electric wire, there exists a possibility that the electrical resistance value in a crimping | compression-bonding part may raise or the crimping force may fall.

Examples of methods for preventing this corrosion include those described in Patent Document 2 and Patent Document 3.
Patent Document 2 includes a metal part made of a first metal material and a second metal material having a standard electrode potential value smaller than that of the first metal material, and at least a surface of the metal part. It is composed of an intermediate layer that is thinly provided by plating and a third metal material having a standard electrode potential smaller than that of the second metal material, and is thinly provided by plating on at least a part of the surface of the intermediate layer. A terminal having a surface layer is disclosed. The first metal material is copper or an alloy thereof, the second metal material is lead or an alloy thereof, tin or an alloy thereof, nickel or an alloy thereof, zinc or an alloy thereof, and the third metal material is Aluminum or its alloys are described.

  In Patent Document 3, in the terminal region of the covered electric wire, the caulking portion formed at one end of the terminal metal fitting is caulked along the outer periphery of the covering portion of the covered electric wire, and at least the end exposed region of the caulking portion and the vicinity thereof A wire harness terminal structure is disclosed in which the entire outer periphery of the wire harness is completely covered with a mold resin.

JP 2004-134212 A JP 2013-33656 A JP 2011-222243 A

  However, although the structure described in Patent Document 3 can prevent corrosion, there is a problem that the manufacturing cost increases due to the addition of the resin molding process, and further, the miniaturization of the wire harness is hindered by the increase of the terminal cross-sectional area due to the resin. In order to carry out the aluminum-based plating that is the third metal material described in 2, an ionic liquid or the like is used, which causes a problem that it is very expensive.

Therefore, the present applicant, in Japanese Patent Application No. 2017-42713, as the anticorrosion terminal material, the coating formed on the core wire contact planned portion where the core wire of the electric wire is contacted with the zinc-nickel alloy layer in order from the substrate side A layered structure of a tin layer and a metal zinc layer was proposed, and a film formed on the planned contact portion to be a contact portion had at least a tin layer, and a structure without a zinc nickel alloy layer and a metal zinc layer was proposed.
In this case, in the partial plating treatment for forming the zinc-nickel alloy layer, it is necessary to mask the portions that are not plated. A masking tape is generally used for masking the plating. However, the attaching work and the peeling work after the plating process are complicated, the workability is poor, and the cost for the masking tape material is excessive. Further, the outermost surface appearance is impaired by the boundary line between the core wire contact planned part and the contact point planned part, and the adhesion may be lowered.

  An object of the present invention is to further improve this anticorrosion terminal material, to be a terminal material that is less susceptible to electrolytic corrosion, to have a good appearance, and to improve the adhesion of the film.

  The anticorrosion terminal material of the present invention has a coating layer laminated on a base material made of copper or a copper alloy, and a core wire contact planned portion where a core wire of an electric wire is contacted when formed on a terminal, and a contact And the coating formed on the core wire contact planned portion includes a zinc-nickel alloy layer containing zinc and nickel, a tin layer made of tin or a tin alloy, and a metal Zinc layers are laminated in this order, and the coating formed on the planned contact portion has the tin layer on the base material, and the zinc-nickel alloy layer is formed on the planned contact portion. An adjacent edge portion of the core wire contact portion has a gradually decreasing portion that gradually decreases in thickness as the contact portion approaches the contact portion, and the contact point portion beyond the gradually decreasing portion includes the zinc nickel Does not have an alloy layer.

In this anticorrosion terminal material, a metal zinc layer is formed in the portion where the core wire is to be contacted. Since the corrosion potential of this metal zinc is close to that of aluminum, the occurrence of electrolytic corrosion when contacting with the aluminum core wire is suppressed. be able to. In addition, the base has a zinc-nickel alloy layer, and the zinc diffuses to the surface of the tin layer, so that the metal zinc layer is maintained at a high concentration. Even if all or part of the metal zinc layer or tin layer disappears due to wear or the like, the occurrence of electrolytic corrosion can be suppressed by the zinc-nickel alloy layer therebelow.
On the other hand, when the metal zinc layer is present on the surface of the tin layer, connection reliability may be impaired in a high temperature and high humidity environment. For this reason, it is possible to suppress the increase in contact resistance even when exposed to a high-temperature and high-humidity environment with a structure in which only the planned contact portion has no metal zinc layer. In the planned contact portion, there is no zinc-nickel alloy layer under the tin layer in order to suppress a decrease in connection reliability due to diffusion of zinc from the base.
In addition, at the edge of the core contact planned portion adjacent to the planned contact portion, a gradually decreasing portion is provided in which the thickness of the zinc-nickel alloy layer is gradually reduced. During processing, cracks and the like are unlikely to occur, and therefore peeling of the film is unlikely to occur.

As a preferred embodiment of the anticorrosion terminal material of the present invention, the gradually decreasing portion has a thickness of 10% from a position where the thickness of the zinc-nickel alloy layer other than the gradually decreasing portion is t and the thickness is 80% of t. Assuming that the width to a position that is less than W is W, the width W is preferably 0.5 mm or more and 15 mm or less.
If the width W is less than 0.5 mm, the width of the gradually decreasing portion is small, so that the portion of the gradually decreasing portion is likely to appear linearly on the surface of the tin layer, and cracking is likely to occur in the portion of the gradually decreasing portion when bent. On the other hand, if the width W exceeds 15 mm, the effect of lowering the corrosion potential of the surface in the gradually decreasing portion becomes poor.

  As a preferred embodiment of the anticorrosion terminal material of the present invention, a base layer made of nickel or a nickel alloy is preferably formed between the base material and the zinc-nickel alloy layer.

The underlayer between the base material and the zinc-nickel alloy layer has an effect of suppressing the diffusion of copper from the base material to the coating surface and increasing the contact resistance when a thermal load is applied.
In this case, the average film thickness of the underlayer is 0.1 μm or more and 5.0 μm or less, the average film thickness of the zinc-nickel alloy layer is 0.1 μm or more and 5.0 μm or less, and the average film thickness of the tin layer Is preferably 0.1 μm or more and 10 μm or less.

In addition, as a preferred embodiment of the anticorrosion terminal material of the present invention, a terminal member having the core wire contact planned portion and the contact planned portion is formed on the carrier portion along the length direction while being formed in a strip shape. A plurality of the carrier portions are connected at intervals in the length direction.
And the anticorrosion terminal of this invention is a terminal which consists of said anticorrosion terminal material, and the electric wire terminal part structure of this invention is crimped | bonded to the terminal of the electric wire which the anticorrosion terminal consists of aluminum or an aluminum alloy.

  In the method for producing a corrosion-resistant terminal material of the present invention, when the zinc-nickel alloy layer is formed by electrolytic plating on the core wire contact planned portion of the base material, the electrode between the electrode in the electrolytic plating tank and the base material is used. Then, a shielding plate is disposed so as to face the planned contact point.

  Since the zinc-nickel alloy layer is not formed on the planned contact portion of the base material by the shielding plate, the masking tape removal operation and the like can be eliminated compared with the method using the masking tape, and the workability is good. When this shielding plate is used, since a current flows around the edge portion of the shielding plate, the gradually decreasing portion can be efficiently formed.

  According to the present invention, since a zinc metal layer having a corrosion potential close to that of aluminum is formed on the surface of the core wire contact planned portion, it is possible to suppress the occurrence of electrolytic corrosion when contacting with the aluminum core wire. Since zinc diffuses from the zinc-nickel alloy layer under the tin layer to the surface portion of the tin layer, the metal zinc layer can be maintained at a high concentration, and has excellent long-term corrosion resistance. 1. Even when all or part of the tin layer disappears due to wear, etc., the zinc-nickel alloy layer below it can suppress the occurrence of electrolytic corrosion, increase the electrical resistance value, and decrease the crimping force to the core wire Can be suppressed. On the other hand, since the planned contact portion has no metallic zinc layer, an increase in contact resistance can be suppressed even when exposed to a high temperature and high humidity environment. In addition, since the thickness of the zinc-nickel alloy layer gradually decreases at the edge of the core contact planned portion adjacent to the planned contact portion, the appearance of the outermost surface is smooth, and the planned contact portion and It is possible to suppress the occurrence of surface peeling and cracking due to the bending process with the core wire contact planned portion.

It is sectional drawing which shows typically embodiment of the anti-corrosion terminal material of this invention. It is a top view of the corrosion-proof terminal material of an embodiment. It is a perspective view which shows the example of the terminal to which the corrosion-proof terminal material of embodiment is applied. It is a front view which shows the terminal part of the electric wire which crimped | bonded the terminal of FIG. It is sectional drawing which shows the plating tank for performing zinc nickel alloy plating to a part of surface of the base material in which the base layer was formed.

The anticorrosion terminal material, anticorrosion terminal, and electric wire terminal part structure of embodiment of this invention are demonstrated.
The anticorrosion terminal material 1 of this embodiment is a strip-shaped material (hoop material) for forming a plurality of terminals, as shown in FIG. 2 as a whole, and along the length direction on both sides thereof. Between the formed carrier parts 21, a plurality of terminal members 22 to be molded as terminals are arranged at intervals in the length direction of the carrier parts 21, and each terminal member 22 has a narrow connecting part 23. Via the carrier part 21. Each terminal member 22 is formed into a terminal shape as shown in FIG. 3, for example, and is cut from the connecting portion 23 to complete the anticorrosion terminal 10.

The anticorrosion terminal 10 is a female terminal in the example of FIG. 3, and a connection portion 11 to which a male terminal 15 (see FIG. 4) is fitted and a core 12 a exposed from the electric wire 12 are caulked from the tip. A wire crimping portion 13 and a covering crimping portion 14 on which the covering portion 12b of the electric wire 12 is caulked are integrally formed in this order. The connecting portion 11 is formed in a rectangular tube shape, and is inserted so that a continuous spring piece 11a is folded from the tip (see FIG. 4).
FIG. 4 shows a terminal structure in which the anticorrosion terminal 10 is caulked to the electric wire 12, and the vicinity of the core wire crimping portion 13 is in direct contact with the core wire 12 a of the electric wire 12. Further, the male terminal 15 contacts the inner surface of the rectangular tube-shaped connecting portion 11 and the spring piece 11 a folded into the connecting portion 11.
Therefore, the part that becomes the connection part 11 and the part that becomes the spring piece 11a in FIG. 2 are the contact point planned part 25, and the part that includes the core wire crimping part 13 below is the core line contact scheduled part 26. Strictly speaking, a portion indicated by a broken line in the planned contact portion 25 is in contact with the male terminal 15, and a portion indicated by a broken line in the core wire contact planned portion 26 is in contact with the core wire. Since it is formed separately on the other side, one side from the midway position in the width direction is a contact planned portion 25 and the other side is a core contact planned portion 26. In addition, since the spring piece 11a is folded back, the planned contact portion 25 is formed on both surfaces of the belt-shaped material.

  And this anti-corrosion terminal material 1 is a film | membrane 8 on the base material 2 which consists of copper or a copper alloy so that the cross section (equivalent to the cross section along the AA line of FIG. 2) was typically shown in FIG. In the surface of the portion excluding the planned contact portion 25, the underlayer 3 made of nickel or a nickel alloy, the zinc-nickel alloy layer 4, and the tin layer 5 are laminated in this order. A zinc metal layer 7 is formed on the tin layer 5 and below the oxide layer 6 formed on the outermost surface thereof. On the other hand, in the planned contact portion 25, the base layer 3 and the tin layer 5 are laminated in this order, and the zinc-nickel alloy layer 4 and the metal zinc layer 7 are not provided. The metal zinc layer 7 is desirably present at a coverage of 30% or more and 80% or less of the surface (the surface of the terminal member 22) after being formed as the terminal 10.

  In this case, the zinc-nickel alloy layer 4 is provided with a uniform film thickness on the entire surface in most of the core wire contact planned portion 26, but in the edge portion adjacent to the contact planned portion 25, the contact planned portion 25, a gradually decreasing portion 4a having a gradually decreasing film thickness as it approaches 25 is provided, and is not provided in the contact planned portion 25 in a portion beyond the gradually decreasing portion 4a. The gradually decreasing portion 4a is formed in a strip shape along the edge of the core contact planned portion 26 adjacent to the planned contact portion 25, and the width of the zinc-nickel alloy layer 4 other than the gradually decreasing portion 4a is formed. Is W, and the width from the position where the film thickness is 80% of t to the position where the film thickness is less than 10% is W, the width W is preferably 0.5 mm or more and 15 mm or less.

If the base material 2 consists of copper or a copper alloy, the composition in particular will not be limited.
Hereinafter, with respect to the film 8, first, a portion excluding the contact planned portion 25 (including the core contact contact portion 26) will be described for each layer.
The underlayer 3 has an average film thickness of 0.1 μm or more and 5.0 μm or less and a nickel content of 80% by mass or more. This underlayer 3 has a function of preventing the diffusion of copper from the base material 2 to the zinc-nickel alloy layer 4 or the tin layer 5, and when the film thickness is less than 0.1 μm, the effect of preventing the diffusion of copper is poor. If it exceeds 5.0 μm, cracking is likely to occur during press working. The film thickness of the underlayer 3 is more preferably 0.3 μm or more and 2.0 μm or less.
Further, when the nickel content is less than 80% by mass, the effect of preventing copper from diffusing into the zinc-nickel alloy layer 4 and the tin layer 5 is small. The nickel content is more preferably 90% by mass or more.

The zinc-nickel alloy layer 4 has an average film thickness of 0.1 μm or more and 5.0 μm or less, contains zinc and nickel, and also contains tin because it is in contact with the tin layer 5. The nickel content of the zinc-nickel alloy layer 4 is 5% by mass or more and 35% by mass or less.
If the thickness of the zinc-nickel alloy layer 4 is less than 0.1 μm, the effect of lowering the corrosion potential of the surface is poor, and if it exceeds 5.0 μm, there is a possibility that cracking may occur during pressing of the terminal 10. The thickness of the zinc-nickel alloy layer 4 is more preferably 0.3 μm or more and 2.0 μm or less.
When the nickel content of the zinc-nickel alloy layer 4 is less than 5% by mass, a substitution reaction occurs during the later-described tin plating for forming the tin layer 5, and the adhesion of the tin plating (tin layer 5) is lowered. When the nickel content in the zinc-nickel alloy layer 4 exceeds 35% by mass, the effect of lowering the corrosion potential of the surface is small. The nickel content is more preferably 7% by mass or more and 20% by mass or less. It is preferable that the zinc-nickel alloy layer is formed at least in the planned contact portion of the core wire and is not present in the planned contact portion in order to prevent contact failure due to zinc diffusion from the base.

The tin layer 5 has a zinc concentration of 0.4 mass% or more and 15 mass% or less. If the zinc concentration of the tin layer 5 is less than 0.4% by mass, the corrosion potential is reduced and the effect of preventing the aluminum wire from being corroded is poor, and if it exceeds 15% by mass, the corrosion resistance of the tin layer 5 is remarkably lowered, so If so, the tin layer 5 may be corroded and contact resistance may deteriorate. The zinc concentration of the tin layer 5 is more preferably 1.5% by mass or more and 6.0% by mass or less.
Moreover, the average film thickness of the tin layer 5 is preferably 0.1 μm or more and 10 μm or less, and if it is too thin, there is a risk of lowering the solder wettability and contact resistance, and if it is too thick, the dynamic friction coefficient of the surface is increased. The attachment / detachment resistance during use with a connector or the like tends to increase.

The metal zinc layer 7 has a zinc concentration of 5 at% to 40 at% and a film thickness of 1 nm to 10 nm in terms of SiO ₂ . If the zinc concentration of the metal zinc layer is less than 5 at%, there is no effect of lowering the corrosion potential, and if it exceeds 40 at%, the contact resistance deteriorates. The zinc concentration of the metal zinc layer 7 is more preferably 10 at% or more and 25 at% or less.
On the other hand, if the SiO ₂ equivalent film thickness of the metal zinc layer 7 is less than 1 nm, the effect of lowering the corrosion potential is poor, and if it exceeds 10 nm, the contact resistance may deteriorate. The SiO ₂ equivalent film thickness is more preferably 1.25 nm or more and 3 nm or less.
A zinc or tin oxide layer 6 is formed on the surface of the metal zinc layer 7.

As described above, the coating 8 having the above layer structure exists on the surface of the portion excluding the contact planned portion 25. As described above, the film 8 having the metal zinc layer 7 is desirably present at a coverage of 30% or more and 80% or less of the surface when formed as the terminal 10.
On the other hand, in the planned contact portion 25, only the base layer 3 and the tin layer 5 made of nickel or a nickel alloy are present in the most part. The composition, film thickness, and the like of each of the foundation layer 3 and the tin layer 5 are the same as those constituting the coating 8 existing on the surface of the portion excluding the contact planned portion 25. Further, a gradually decreasing portion 4 a that gradually decreases in thickness as it approaches the planned contact portion 25 is formed at an edge portion adjacent to the planned contact portion 25 in the planned core wire contact portion 26.

The nickel content in the zinc-nickel alloy layer 4, the zinc concentration in the tin layer 5, the film thickness and zinc concentration in the metal zinc layer 7, and the coverage of the metal zinc layer 7 can be measured by the following methods.
The nickel content of the zinc-nickel alloy layer 4 was determined by preparing an observation sample obtained by thinning the sample to 100 nm or less using a focused ion beam device: FIB (model number: SMI3050TB) manufactured by Seiko Instruments Inc. Is observed at an acceleration voltage of 200 kV using a scanning transmission electron microscope manufactured by JEOL Ltd .: STEM (model number: JEM-2010F), and an energy dispersive X-ray analyzer attached to STEM: EDS (manufactured by Thermo) ) To measure.
The zinc concentration in the tin layer 5 is measured using an electron beam microanalyzer: EPMA (model number JXA-8530F) manufactured by JEOL Ltd. with an acceleration voltage of 6.5 V and a beam diameter of 30 μm.

As for the thickness and zinc concentration of the metal zinc layer 7, for each sample, an XPS (X-ray Photoelectron Spectroscopy) analyzer manufactured by ULVAC-PHI Co., Ltd .: ULVAC PHI model-5600LS was used, and the sample surface was etched with argon ions. Measured by XPS analysis. The analysis conditions are as follows, for example.
X-ray source: Standard MgKα 350W
Path energy: 187.85 eV (Survey), 58.70 eV (Narrow)
Measurement interval: 0.8 eV / step (Survey), 0.125 eV (Narrow)
)
Photoelectron extraction angle with respect to sample surface: 45 deg
Analysis area: about 800μmφ

For the film thickness, the “SiO ₂ equivalent film thickness” is calculated from the time required for the measurement using the etching rate of SiO ₂ measured in advance by the same model.
The etching rate of SiO ₂ is calculated by dividing the SiO ₂ film having a thickness of 20 nm by argon ions in a rectangular area of 2.8 × 3.5 mm and dividing the time required for etching 20 nm. Calculated by In the case of the above analysis apparatus, for example, it took 8 minutes, so the etching rate is 2.5 nm / min. XPS has an excellent depth resolution of about 0.5 nm, but the etching time with the Ar ion beam varies depending on the material. Therefore, to obtain a numerical value of the film thickness, a sample with a known and flat film thickness is procured. Then, the etching rate must be calculated. Since the above is not easy, the “SiO ₂ equivalent film thickness” calculated from the time required for etching is defined by the etching rate calculated for the SiO ₂ film whose film thickness is known. Therefore, it should be noted that the “SiO ₂ equivalent film thickness” is different from the actual oxide film thickness. When the film thickness is defined by the SiO ₂ conversion etching rate, even if the actual film thickness is unknown, the film thickness is unambiguous and can be quantitatively evaluated.
Note that this SiO ₂ equivalent film thickness is the thickness of the portion where the metal zinc concentration is equal to or higher than the predetermined value. Even when the concentration of the metal zinc can be measured partially, the layer is extremely thinly dispersed. In some cases, it is not possible to measure the film thickness in terms of SiO ₂ .

Next, the manufacturing method of this anti-corrosion terminal material 1 is demonstrated.
A plate material made of copper or a copper alloy is prepared as the substrate 2. By cutting or punching the plate material, as shown in FIG. 2, a plurality of terminal members 22 are connected to the carrier portion 21 via a connecting portion 23 to form a long strip-shaped material. To do. Then, after the surface is cleaned by performing degreasing, pickling, etc. on the belt-shaped material, nickel or nickel alloy plating for forming the underlayer 3 is applied to the entire surface, and then the cord contact planned portion 26 is subjected to zinc-nickel alloy plating for forming the zinc-nickel alloy layer 4 and then tin or tin-alloy plating for forming the tin layer 5 on the entire surface.

The nickel or nickel alloy plating for forming the underlayer 3 is not particularly limited as long as a dense nickel-based film can be obtained, and electroplating using a known watt bath, sulfamic acid bath, citric acid bath, or the like. Can be formed. As nickel alloy plating, nickel tungsten (Ni-W) alloy, nickel phosphorus (Ni-P) alloy, nickel cobalt (Ni-Co) alloy, nickel chromium (Ni-Cr) alloy, nickel iron (Ni-Fe) alloy, A nickel boron (Ni-B) alloy or the like can be used.
Considering the press bendability to the anticorrosion terminal 10 and the barrier property against copper, pure nickel plating obtained from a sulfamic acid bath is desirable.

The zinc-nickel alloy plating for forming the zinc-nickel alloy layer 4 is not particularly limited as long as a dense film can be obtained with a desired composition, and a known sulfate bath, chloride salt bath, neutral bath, etc. Can be used.
When this zinc-nickel alloy plating is performed, electrolytic plating is performed using a shielding plate so that the zinc-nickel alloy layer 4 is not formed on the planned contact portion 25. FIG. 5 shows a plating tank for applying a zinc-nickel alloy plating to a part of the surface while continuously feeding a strip-shaped material (material to be plated) 51 in which the base layer 3 is formed on the base material 2 in the length direction. FIG. A plating material 51 is caused to travel along the length direction in the central portion of the plating tank 52 in which the plating solution 53 is stored. The plating material 51 is used as a cathode, and a current is passed between the anode electrodes 54 arranged on both sides thereof. The zinc nickel alloy is adhered to the surface of the material 51 to be plated. At this time, the shielding plate 55 is disposed so as to cover the surface of the contact planned portion 25 of the material 51 to be plated.

In this case, the to-be-plated material 51 is arrange | positioned so that the width direction may be made into the up-down direction, the core wire contact plan part 26 of the lower side part of the width is arrange | positioned, and the contact plan part 25 is arrange | positioned in the upper part. .
The shielding plate 55 is formed of a material which is not corroded by the plating solution with an insulator made of, for example, non-conductive vinyl chloride resin, acrylic resin or the like, and has a slight gap on the surface of the contact point planned portion 25 of the material 51 to be plated. And facing each other and arranged parallel to the material 51 to be plated. The gap g between the material to be plated 51 and the shielding plate 55 is preferably 1 mm or more and 10 mm or less. If the gap g is less than 1 mm, the material to be plated 51 and the shielding plate 55 may come into contact with each other and damage the surface of the material to be plated 51. If the gap g exceeds 10 mm, the shielding function is impaired. Then, plating is performed on the surface facing the shielding plate 55 in a wide range.
In FIG. 5, shielding plates 55 are provided so as to face both surfaces of the material 51 to be plated. However, when the core contact portion 26 is disposed only on one surface, the opposite surface is tape or The entire surface may be masked with the same shielding plate.

  As described above, since the gradually decreasing portion 4a is formed at the edge portion of the zinc-nickel alloy layer 4, the shielding plate 55 is disposed in anticipation of the region where the gradually decreasing portion 4a is formed. Specifically, the shielding plate 55 covers the entire contact point portion 25 arranged on the upper portion of the width of the material 51 and further gradually decreases from the boundary between the core wire contact portion 26 and the contact point portion 25. 4a is formed at the lower end edge of the shielding plate 55 such that the edge of the shielding plate 55 is disposed at a position (a position indicated by a chain line in FIG. 5) that enters the core wire contact planned portion 26 side by an amount corresponding to the width formed. Is arranged so as to cover the upper edge portion of the core wire contact planned portion 26. In other words, the position of the edge of the shielding plate 55 is set so that the gradually decreasing portion 4 a is not formed on the planned contact portion 25.

When the shielding plate 55 is thus arranged and electrolytic plating is performed, the current flowing between the material to be plated 51 and the anode electrode 54 flows at a high current density in a region not covered by the shielding plate 55, whereas The portion covered with the shielding plate 55 is shielded by the shielding plate 55 and hardly flows. Since the zinc-nickel alloy plating does not adhere to the material 51 to be plated when the current density is low, it does not adhere to the portion covered with the shielding plate 55. However, since the current flows around the edge of the shielding plate 55, plating according to the current density adheres to form the gradually decreasing portion 4a.
If an organic additive is added to the plating solution in order to improve the film thickness distribution, the current efficiency is improved even in the low current density portion, and the zinc-nickel alloy plating may be uniformly formed on the strip material. Therefore, it is desirable to reduce or not add the organic additive in order to form the gradually decreasing portion of the zinc-nickel alloy plating.

  Tin or tin alloy plating for forming the tin layer 5 can be performed by a known method. For example, an organic acid bath (for example, a phenol sulfonic acid bath, an alkane sulfonic acid bath or an alkanol sulfonic acid bath), borofluoric acid Electroplating can be performed using an acidic bath such as a bath, a halogen bath, a sulfuric acid bath, or a pyrophosphoric acid bath, or an alkaline bath such as a potassium bath or a sodium bath.

Thus, after plating on the base material 2, heat treatment is performed.
In this heat treatment, heating is performed at a temperature at which the surface temperature of the material becomes 30 ° C. or higher and 190 ° C. or lower. By this heat treatment, zinc in the zinc-nickel alloy plating layer diffuses in the tin plating layer and on the tin plating layer at portions other than the planned contact portion 25, and a thin metal zinc layer 7 is formed on the surface. Since zinc diffusion occurs rapidly, the metallic zinc layer 7 can be formed by exposing it to a temperature of 30 ° C. or higher for 24 hours or longer. However, since the zinc-nickel alloy repels molten tin and forms a tin repelling portion in the tin layer 5, it is not heated to a temperature exceeding 190 ° C.

The anticorrosion terminal material 1 manufactured in this way has a base layer 3 made of nickel or a nickel alloy formed on a base material 2, and the planned contact portion 25 covered with a mask has an upper surface of the base layer 3. A tin layer 5 is formed on the base layer 3, and a zinc-nickel alloy layer 4, a tin layer 5, and a metal zinc layer 7 are formed on the surface of the metal zinc layer 7. The oxide layer 6 is thinly formed.
And it forms in the shape of the terminal shown in FIG. 3 with a strip | belt shape by press work etc., and it forms in the corrosion-proof terminal 10 by cut | disconnecting the connection part 23. FIG.
FIG. 4 shows a terminal portion structure in which the terminal 10 is caulked to the electric wire 12, and the vicinity of the core caulking portion 13 is in direct contact with the core wire 12 a of the electric wire 12.

In the anticorrosion terminal 10, the core wire contact portion 26 includes zinc in the tin layer 5, and the metal zinc layer 7 is formed under the outermost oxide layer 6 of the tin layer 5. Even in the state of being crimped to the core wire 12a, the corrosion potential of the metallic zinc is very close to that of aluminum, so that the occurrence of electrolytic corrosion can be prevented. In this case, since the base material 2 is not exposed on the end face of the terminal 10 because the plating treatment is performed in the state of the strip-shaped material in FIG. 2 and the heat treatment is performed, an excellent anticorrosive effect can be exhibited.
Moreover, since the zinc-nickel alloy layer 4 is formed under the tin layer 5 and the zinc diffuses into the surface portion of the tin layer 5, the disappearance of the metal zinc layer 7 due to wear or the like is suppressed, and the metal zinc Layer 7 is maintained at a high concentration. Even if all or part of the tin layer 5 disappears due to wear or the like, the zinc-nickel alloy layer 4 therebelow has a corrosion potential close to that of aluminum, so that the occurrence of electrolytic corrosion can be suppressed.

  On the other hand, when the metal zinc layer 7 is present on the surface of the tin layer 5, connection reliability may be impaired in a high-temperature and high-humidity environment. In this embodiment, the contact point portion 25 includes the metal zinc layer 7. By adopting a structure that does not exist, an increase in contact resistance can be suppressed even when exposed to a high temperature and high humidity environment.

Further, as described above, at the end edge portion of the core wire contact planned portion 26 adjacent to the planned contact portion 25, the gradually decreasing portion gradually decreases as the thickness of the zinc-nickel alloy layer 4 approaches the planned contact portion 25. 4a is formed. For this reason, the surface of the tin layer 5 formed over the entirety of the contact planned portion 25 and the core wire contact planned portion 26 is formed smoothly, and a step is formed at the boundary between the contact planned portion 25 and the core wire contact planned portion 26. Is produced and a good appearance is achieved.
When the planned contact portion 25 is masked with a masking tape at the time of zinc-nickel alloy plating, the adhesive component of the masking tape may remain even if the masking tape is peeled off after the zinc-nickel alloy plating treatment. Organic solvents, electrolytic degreasing, strong acids, and strong alkalis are used to remove this adhesive component, but organic solvents have high safety risks (local exhaust requires organic only, explosion-proof specifications due to flash point issues, etc.) Chemical cost is high. Furthermore, treatments such as electrolytic degreasing may damage the zinc-nickel alloy layer. Further, when the masking tape is applied, it is necessary to dry the surface of the material. However, since a thick oxide film is easily formed by drying, particularly when the underlayer 3 made of nickel is dried, a strong nickel oxide film is formed. It has produced | generated and became the cause of reducing the adhesiveness of the plating on it (a contact point plan part is tin plating, and a core wire contact plan part is zinc nickel alloy plating).
On the other hand, in the case of this embodiment, since the masking is performed by the shielding plate 55, the workability is good because there is no need for a peeling operation or a drying operation after the plating process like the masking tape, and the masking tape is used. In this case, the problem can be solved and a film having excellent adhesion can be formed.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

After degreasing and pickling the belt-shaped material made of the copper plate of the base material, the entire surface thereof is plated with nickel to form the underlayer 3, and then the contact planned portion 25 using the shielding plate 55 as shown in FIG. Zinc-nickel alloy plating was applied. At this time, the gap g between the belt-shaped material and the shielding plate 55 is changed from 2 mm to 12 mm, and the contact point planned portion 25 and the core wire contact planned portion 26 have a 1: 1 area ratio. A plurality of samples having different widths of the gradually decreasing portions were produced by changing the position of the edge portion. Further, after that, tin plating was performed on the entire surface. This series of processes was continuously performed while the belt-shaped material 51 was running. Further, the planned contact portion 25 and the planned core wire contact portion 26 were formed to have the same area so that the area ratio was 1: 1. Next, heat treatment is performed at a temperature of 30 ° C. to 190 ° C. for 1 hour to 36 hours to diffuse zinc from the base to the surface, thereby forming the metal zinc layer 7, thereby forming a metal in a portion excluding the contact planned portion 25. An anticorrosion terminal material 1 having a zinc layer 7 was obtained. The coverage of the metal zinc layer 7 is 50%.
For comparison, after drying the belt-shaped material formed up to the base layer 3 in the same manner as in the example, a film (K-2140B) manufactured by Hitachi Chemical Co., Ltd. In order to remove the oxide film generated on the surface of the base layer 3 by masking and drying, pickling with hydrochloric acid was performed. Next, after the zinc-nickel alloy plating for forming the zinc-nickel alloy layer 4 is performed, the film (hereinafter referred to as masking tape) is peeled off, washed with hot water to remove the adhesive component residue of the masking tape, and then the entire surface is tinned. Tin or tin alloy plating to form layer 5 was applied.

The conditions for each plating were as follows.
<Nickel plating conditions>
・ Plating bath composition Nickel sulfamate: 300 g / L
Nickel chloride: 5g / L
Boric acid: 30 g / L
・ Bath temperature: 45 ℃
・ Current density: 5 A / dm ²

<Zinc-nickel alloy plating conditions>
・ Plating bath composition Zinc sulfate heptahydrate: 75 g / L
Nickel sulfate hexahydrate: 180 g / L
Sodium sulfate: 140 g / L
・ PH = 2.0
・ Bath temperature: 45 ℃
・ Current density: 5 A / dm ²

<Tin plating conditions>
・ Plating bath composition Tin methanesulfonate: 200 g / L
Methanesulfonic acid: 100 g / L
Brightener and bath temperature: 25 ° C
・ Current density: 5 A / dm ²

About the obtained sample, each average film thickness of the base layer, the zinc nickel alloy layer, and the tin layer was measured. These film thicknesses were measured by observing the cross section with a scanning ion microscope.
Moreover, the external appearance of the boundary part of a contact plan part and a core wire contact plan part was visually observed. And the thing which can confirm that the boundary as a line less than 0.5 mm in width | variety is set to "x", and the thing which cannot be confirmed as a line is set to "(circle)".
In addition, it was confirmed whether or not there was unevenness that could be visually determined for each of the contact planned portion and the core wire contact planned portion. The case where the unevenness was confirmed was indicated as “×”, and the case where the unevenness was not confirmed was indicated as “◯”. The cause of this unevenness is due to the residue of the oxide film of the underlayer before the zinc-nickel alloy plating, the hydrogen gas is generated during the zinc-nickel alloy plating, the masking tape before the tin plating Examples include those caused by residues and those caused by residues of the oxide film of the base layer before tin plating.
Regarding the width of the gradually decreasing portion, the thickness of the zinc-nickel alloy layer other than the gradually decreasing portion is t, and the width from the position where the film thickness is 80% of t to the position where the film thickness is less than 10% is measured. Further, when the width of the gradually decreasing portion was less than 0.1 mm, the measurement result of the width of the gradually decreasing portion was set to 0 mm.
These results are shown in Table 1.

For the above samples, the following cross-cut test and bending test were performed in order to examine the adhesion of the film.
<Cross cut test>
A planned contact portion and a core wire contact portion are cut out from the test piece, tested by the cross-cut method described in JISK5600-5-6, and “○” indicates that the film was not peeled off, and “×” indicates that the film was peeled off. It was.
<Bending test>
Cut the test piece into a strip with a width of 10 mm so that the area of the planned contact portion and the planned core contact portion is 1: 1, and bend so that the boundary between the planned contact portion and the planned core contact portion is a bent portion. After 120 ° bending with a radius of 1.5 mm, bending back was performed. The surface of the bent outer peripheral portion of the sample was observed with an optical microscope (magnification 50 times) to examine whether there was any abnormality. The plate thickness of the copper or copper alloy substrate was 0.3 mm. The case where a state different from the flat plate state such as peeling, cracking or cracking was observed in the bent back portion was indicated as “X”, and the case where no abnormality was observed was indicated as “◯”.

Moreover, the sample was shape | molded into the 090 type | mold terminal and the pure aluminum wire was crimped. After leaving the terminals crimped with pure aluminum wires in corrosive environment, high temperature and high humidity environment, and high temperature environment, contact resistance between aluminum wires and terminals, or contact resistance between terminals when terminals are fitted together It was measured.
<Salt water environment test>
A 090 type female terminal crimped with a pure aluminum wire was immersed in a 5% sodium chloride aqueous solution at 23 ° C. for 24 hours, and then left under high temperature and high humidity at 85 ° C. and 85% RH for 24 hours. Thereafter, the contact resistance between the aluminum wire and the terminal was measured by a four-terminal method. The current value was 10 mA.
<Corrosion gas environment test>
090 type female terminal crimped with pure aluminum wire, compliant with JIS C60068-2-42, SO ₂ gas concentration 25 ± 5 ppm, temperature 25 ± 2 ° C., humidity 75 ± 5%, air flow rate 1000 L / h And left in a corrosive environment for 96 hours. Then, the male terminal which implemented 090 type tin plating was fitted, and the contact resistance between terminals was measured by the four-terminal method.
These results are shown in Table 2.

From these results, Samples 1 to 9 having a gradually decreasing width W of 0.5 mm or more and 15 mm or less have a smooth appearance near the boundary between the contact planned portion and the core wire contact planned portion, no unevenness, and good adhesion. there were. Moreover, peeling, cracks, cracks, and the like were not observed in the bending test at the gradually decreasing portion.
Among them, Samples 1 to 7 had satisfactory results in the salt water environment leaving test and the corrosive gas environment leaving test because each of the underlayer, the zinc nickel alloy layer, and the tin layer had a sufficient film thickness. .
On the other hand, Samples 10 and 11 had a gradually decreasing width and a high contact resistance value after the salt water environment leaving test. This is because, as the width of the gradually decreasing portion is larger, the range in which the thickness of the zinc-nickel alloy layer is thinner becomes larger, and the effect of lowering the corrosion potential on the surface is reduced.
In Samples 12 to 15, the width of the gradually decreasing portion was small, and a line was visually confirmed at the boundary portion between the contact planned portion and the core wire contact planned portion. In particular, Samples 12 and 14 were cracked at the interface. Moreover, peeling occurred in the cross-cut test of the planned contact portion. This is considered to be because an oxide film was generated in the nickel plating of the underlayer when it was once dried for masking the planned contact portion as a comparison process. Alternatively, it may be due to an adhesive component residue of the masking tape that could not be removed from the planned contact portion.

DESCRIPTION OF SYMBOLS 1 Corrosion-proof terminal material 2 Base material 3 Base layer 4 Zinc nickel alloy layer 5 Tin layer 6 Oxide layer 7 Metal zinc layer 10 Terminal 11 Connection part 12 Electric wire 12a Core wire 12b Covering part 13 Core wire crimping part 14 Covering crimping part 25 Contact Scheduled portion 26 Core wire contact planned portion 51 Strip material 52 Electrolytic plating tank 53 Plating solution 54 Anode electrode 55 Shielding plate

Claims (7)

  A coating is laminated on a base made of copper or a copper alloy, and a core contact planned portion where the core of the electric wire is contacted when formed into a terminal, and a planned contact portion serving as a contact portion The coating formed on the core wire contact portion is formed by laminating a zinc-nickel alloy layer containing zinc and nickel, a tin layer made of tin or tin alloy, and a metal zinc layer in this order. The coating formed on the planned contact portion has the tin layer on the base material, and the zinc-nickel alloy layer is adjacent to the planned contact portion of the core wire. The end edge portion has a gradually decreasing portion that gradually decreases in thickness as it approaches the contact planned portion, and the contact point portion beyond the gradually decreasing portion does not have the zinc-nickel alloy layer. Corrosion-proof terminal material.   When the thickness from the position where the film thickness of the zinc-nickel alloy layer other than the gradually decreasing part is t and the film thickness is 80% of the thickness to the position where the film thickness is less than 10% is W, The width W is 0.5 mm or more and 15 mm or less, The anticorrosion terminal material of Claim 1 characterized by the above-mentioned.   The anticorrosion terminal material according to claim 1 or 2, wherein a base layer made of nickel or a nickel alloy is formed between the base material and the zinc-nickel alloy layer.   The undercoat layer has an average film thickness of 0.1 μm or more and 5.0 μm or less, the zinc-nickel alloy layer has an average film thickness of 0.1 μm or more and 5.0 μm or less, and the tin layer has an average film thickness of 0.00. It is 1 micrometer or more and 10 micrometers or less, The anticorrosion terminal material of Claim 3 characterized by the above-mentioned.   A plurality of terminal members having the core wire contact planned portion and the contact point planned portion are connected to the carrier portion along the length direction thereof at intervals in the length direction of the carrier portion. The anticorrosion terminal material according to any one of claims 1 to 4, wherein the anticorrosion terminal material is formed.   An anticorrosion terminal comprising the anticorrosion terminal material according to any one of claims 1 to 5.   It is a method of manufacturing the corrosion-proof terminal material as described in any one of Claim 1 to 6, Comprising: When forming the said zinc nickel alloy layer on the said core wire contact plan part of the said base material by electroplating, it is electrolysis The manufacturing method of the corrosion-proof terminal material characterized by arrange | positioning a shielding board so that the said contact scheduled part may be opposed between the electrode in a plating tank, and the said base material.

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