JP2022119436A - Anti-corrosion terminal material for aluminum core wire, anti-corrosion terminal, and electric wire terminal structure - Google Patents

Abstract

To provide an anti-corrosion terminal material for aluminum core wire, having high anti-corrosion effect as terminal to be crimped to a terminal of electric wire including aluminum core wire, an anti-corrosion terminal made of the anti-corrosion terminal material, and an electric wire terminal structure with use of the anti-corrosion terminal.SOLUTION: The material includes a base material made of metal with a coating. A terminal formed from the material has a portion expected to crimp core wire, as inner surface of the part for crimping the core wire, and a portion other than the portion expected to crimp core wire. The coating includes a first coating formed on the portion expected to crimp core wire, which is made of nickel, copper, cobalt, molybdenum, manganese, lead, iron, silver, gold, platinum, titanium, palladium, antimony, or alloy thereof, and a second coating formed on the portion other than the portion expected to crimp core wire, which has a tin layer made of tin or tin alloy on the surface.SELECTED DRAWING: Figure 1

Description

The present invention uses a corrosion-resistant terminal material for an aluminum core wire which is used as a terminal to be crimped to the end of an electric wire made of an aluminum core wire and has a high corrosion-preventing effect, a corrosion-resistant terminal made of the corrosion-resistant terminal material, and a corrosion-resistant terminal using the corrosion-resistant terminal. It relates to an electric wire terminal structure.

Conventionally, a terminal made of copper or a copper alloy is crimped to the end of a wire made of copper or a copper alloy, and the wire is connected to a device by connecting the terminal to a terminal provided on the device. A connection is being made. Also, in order to reduce the weight of the electric wire, it is being studied to form the core wire of the electric wire from aluminum or an aluminum alloy instead of copper or a copper alloy.

By the way, if the electric wire (conductor) is made of aluminum or an aluminum alloy and the terminal is made of copper or a copper alloy, when an aqueous solution of electrolyte such as salt water adheres to the crimped part of the electric wire and the terminal, the potential difference between the dissimilar metals Galvanic corrosion due to dissimilar metals may occur. Corrosion of the wire may lead to an increase in electrical resistance and a decrease in crimping force at the crimping portion.

Methods for preventing such corrosion between dissimilar metals are described in Patent Documents 1 to 4, for example.
Japanese Patent Laid-Open No. 2004-100003 describes that the exposed region of the crimped portion (core wire crimping portion) of the terminal for crimping the conductor and the entire circumference of the vicinity thereof are covered with a mold resin.

In Patent Document 2, a barrel piece for crimping a conductor is formed longer than the conductor exposed portion, and when the conductor is crimped, the barrel piece continuously and integrally surrounds the conductor exposed portion to the tip of the insulation coating, and the barrel It is described that the tip of the piece is engaged with the bottom surface of the barrel to ensure a water stopping function.

In Patent Document 3, a Zn plating layer having an electrode potential intermediate to that of aluminum is formed on a Sn plating layer covering a terminal material. Further, in Patent Document 4, a Ni—Zn plating layer is formed as a dissimilar metal contact corrosion prevention layer on a Sn plating layer covering a terminal material.

JP 2011-222243 A JP 2017-17036 A Japanese Patent Application Laid-Open No. 2019-90089 JP 2019-178375 A

However, providing a mold resin as described in Patent Document 1 or forming a special-shaped barrel piece as described in Patent Document 2 increases the manufacturing cost.
In addition, when a tin-plated layer is formed as in Patent Documents 3 and 4, tin and aluminum do not form an intermediate phase or an intermetallic compound, resulting in poor adhesion. Therefore, when the pressure of the core wire crimping part weakens due to corrosion, a gap is created between the terminal and the aluminum wire. There is a risk that the contact area that is Patent Documents 1 and 2 specify a general Sn-plated copper alloy terminal structure, and do not discuss the plating inside the core wire crimping portion.

The present invention has been made in view of the above-mentioned problems, and comprises a corrosion-resistant terminal material for an aluminum core wire, which has a high corrosion-preventing effect as a terminal to be crimped to the end of an electric wire made of an aluminum core wire, and the corrosion-resistant terminal material. An object of the present invention is to provide an anti-corrosion terminal and an electric wire terminal structure using the anti-corrosion terminal.

The anti-corrosion terminal material for an aluminum core wire of the present invention is formed by forming a film on a base material made of metal, and when formed into a terminal, a core wire crimping portion that will be the inner surface of the portion to which the core wire of the electric wire is crimped. , and a portion other than the portion to be crimped on the core wire, and the first coating formed on the portion to be crimped on the core wire among the coatings is nickel, copper, cobalt, molybdenum, manganese, lead, iron , silver, gold, platinum, titanium, palladium, antimony, or an alloy thereof, and a second film having a tin layer made of tin or a tin alloy is formed on the surface of the portion other than the portion to be crimped. there is

Elements of nickel, copper, cobalt, molybdenum, manganese, lead, iron, silver, gold, platinum, titanium, palladium, and antimony (hereinafter referred to as designated elements) contained in the first film in the corrosion-proof terminal material for aluminum core wires forms an intermetallic compound with aluminum. Therefore, by using this first film on the portion to be crimped on the core wire, an intermetallic compound is formed in a state in which the aluminum core wire is in contact with the core wire, thereby enhancing adhesion.
An alloy of any of these specified elements can improve the adhesion, but in order to obtain the desired adhesion, it is more preferable that the content of the specified element is 60% by mass or more.
In addition, if the first coating is exposed to a portion other than the portion to be crimped on the core wire, it may corrode if it contacts or approaches the aluminum core wire in a corrosive environment such as salt water. By forming a second film with a tin layer on the surface, it is possible to prevent corrosion and provide a terminal material that is excellent in solder wettability and contact resistance.

In this anti-corrosion terminal material for aluminum core wires, the film thickness of the first film is preferably 0.1 μm or more and 8.0 μm or less.
If the thickness of the first coating is less than 0.1 μm, the coating may be broken during bending or crimping.

In this anti-corrosion terminal material for an aluminum core wire, it is preferable that the second film is formed by forming the tin layer on a nickel-zinc alloy layer.

Even if the core wire is crimped at the core wire crimping part of the terminal, if the tip of the core wire is exposed from the core wire crimping part, corrosion will occur between the exposed surface of the terminal other than the core wire crimping part. Concerned.
In this anti-corrosion terminal material, the second film in the portion other than the portion to be crimped on the core wire has a laminated structure of a nickel-zinc alloy layer and a tin layer, and zinc in the nickel-zinc alloy layer diffuses into the tin layer. Therefore, the corrosion potential of the tin layer is close to that of aluminum, and the occurrence of galvanic corrosion can be suppressed even if the tin layer comes into contact with or comes close to the aluminum core wire. In addition, the second coating has a zinc layer under the tin layer, so even if all or part of the tin layer disappears due to wear or the like, galvanic corrosion of different metals will occur due to the zinc layer underneath. can be suppressed, and an increase in the contact resistance value can be suppressed.

In this anti-corrosion terminal material for an aluminum core wire, a third coating may be formed in place of the second coating on the intended contact portion that will become a contact when formed into a terminal, and the surface of the third coating is It is formed by the tin layer and does not have the nickel-zinc alloy layer.

Since the contact part when formed into a terminal is separated from the aluminum core wire, the influence of corrosion is small, and zinc may be omitted. Moreover, since it does not have a zinc layer, it has the effect of suppressing an increase in contact resistance at the contact portion due to diffusion of zinc into the tin layer when a thermal load is applied.

Further, the corrosion-resistant terminal for an aluminum core wire of the present invention is a terminal made of the above-described corrosion-resistant terminal material, and the electric wire end portion structure of the present invention is an electric wire end in which the corrosion-resistant terminal is made of an aluminum or aluminum alloy aluminum core wire. is crimped to
In this case, an intermetallic compound may be formed in a state in which the anti-corrosion terminal and the aluminum core wire are in contact with each other.

According to the present invention, since the designated element contained in the surface of the first coating forms an intermetallic compound with aluminum, by using it in the core wire crimping part, the adhesion to the aluminum core wire is enhanced, It is possible to suppress an increase in contact resistance even in a corrosive environment.

BRIEF DESCRIPTION OF THE DRAWINGS It is principal part sectional drawing which shows typically 1st Embodiment of the corrosion-proof terminal material of this invention. It is a top view of the anti-corrosion terminal material of embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the example of the corrosion-proof terminal to which the corrosion-proof terminal material of embodiment is applied. FIG. 4 is a cross-sectional view showing a terminal portion of an electric wire to which the anticorrosive terminal of FIG. 3 is crimped; FIG. 5 is a cross-sectional view schematically showing a third embodiment of the present invention; FIG. 5 is a cross-sectional view schematically showing a fourth embodiment of the invention; It is an enlarged view of the member for terminals in the corrosion-proof terminal material of 3rd Embodiment. FIG. 8 is a cross-sectional view showing a state of connection between a corrosion-resistant terminal formed of the corrosion-resistant terminal material of FIG. 7 and a male terminal;

An anti-corrosion terminal material for an aluminum core wire, an anti-corrosion terminal, and an electric wire end portion structure of an embodiment of the present invention will be described.

A corrosion-proof terminal material for aluminum core wires (hereinafter simply referred to as a corrosion-proof terminal material) 1 of the present embodiment is, as shown in FIG. ), and a plurality of terminal members 22 formed as terminals are arranged at intervals in the length direction of the carrier portion 21 between a pair of long strip-shaped carrier portions 21 extending in parallel. , each terminal member 22 is connected to both carrier portions 21 via narrow connecting portions 23 . Each terminal member 22 is molded into, for example, a shape as shown in FIGS. 3 and 4, and is cut from the connecting portion 23 to complete the anticorrosion terminal 10 .

The anti-corrosion terminal 10 is a female terminal in the examples of FIGS. A core wire crimping portion 13 to be crimped and a covering crimping portion 14 to which a covering portion 12b of the electric wire 12 is crimped are arranged in this order and integrally formed. The connecting portion 11 is formed in a square tubular shape, and a spring piece 11a continuing to the tip thereof is inserted so as to be folded inside.
FIG. 4 shows the structure of the terminal portion in which the corrosion-proof terminal 10 is crimped to the electric wire 12. As shown in FIG. In this electric wire end portion structure, the core wire crimping portion 13 and its vicinity are in direct contact with the core wire 12 a of the electric wire 12 .

In the strip material shown in FIG. 2, the same reference numerals as those used when forming the anticorrosion terminal 10 are given to the respective parts. Also, in this strip material, a portion to be the inner surface of the core wire crimping portion 13 when the corrosion-proof terminal 10 is formed is defined as a core wire crimping planned portion 25 .
In the figure, reference numeral 16 denotes a serration portion formed on the surface of the portion 25 to be crimped. Become.

[First embodiment]
As shown schematically in cross section in FIG. 1, the anticorrosive terminal material 1 of the first embodiment has a base material 2 made of metal and a first film 3 is formed on a portion 25 to be crimped on the core wire. A second film 4 is formed on a region other than the portion to be crimped 25 .

The composition of the base material 2 is not particularly limited as long as it is made of a metal having conductivity, but is preferably made of copper or a copper alloy. A -Mg-based copper alloy (C18665) or the like can be applied. Alternatively, it may be composed of a plated material obtained by applying copper plating, copper alloy plating, tin plating, or tin alloy plating to the surface of a base material made of metal.

The first film 3 formed on the core wire crimping portion 25 includes nickel, copper, cobalt, molybdenum, manganese, lead, iron, silver, gold, platinum, titanium, palladium, and antimony (these elements are referred to as designated elements). or an alloy thereof, and in the case of an alloy, these designated elements should be present in the coating in the largest amount in terms of mass percentage.
These specified elements are elements capable of forming an intermetallic compound with aluminum. By forming the first coating 3 containing these designated elements on the core wire crimping portion 25, the surface of the first coating 3 is crimped to the aluminum core wire 12a or is bitten into the aluminum core wire 12a by the serration portion 16. In this state, an intermetallic compound is formed between the designated element in the first coating 3 and the aluminum of the aluminum core wire 12a, thereby enhancing adhesion.

If this specified element is not present in the film in the highest amount, the effect of forming an intermetallic compound with the aluminum of the aluminum core wire is poor, the desired adhesion cannot be obtained, and the contact resistance may increase in a corrosive environment. There is The content of the designated element is preferably 60% by mass or more. When two or more specified elements are contained, the total mass percentage of these specified elements should be the largest, and the total is preferably 60 mass % or more.
Moreover, the film thickness of the first film 3 is preferably 0.1 μm or more and 8.0 μm or less. If the film thickness of the first coating 3 is less than 0.1 μm, the coating may be broken during bending or crimping.

The second film 4 formed on the region other than the portion to be crimped 25 has a tin layer made of tin or a tin alloy as the outermost layer.
In the first embodiment, the second film 4 is formed by laminating a nickel layer 6 made of nickel or a nickel alloy, a nickel-zinc alloy layer 7 made of a nickel-zinc alloy, and a tin layer 8 made of a tin alloy in this order. there is In this case, zinc in the nickel-zinc alloy layer 7 diffuses into the tin layer 8 . Therefore, the tin layer 8 of the second coating 4 has a corrosion potential close to that of aluminum, and corrosion can be suppressed when the tin layer 8 comes close to the aluminum core wire 12a.

The nickel layer 6 preferably has a thickness of 0.1 μm or more and 5.0 μm or less and a nickel content of 80% by mass or more. This nickel layer 6 has a function of preventing diffusion of copper from the substrate 2 . If the thickness of the nickel layer 6 is less than 0.1 μm, the effect of preventing the diffusion of copper is poor.
Moreover, if the nickel content of the nickel layer 6 is less than 80% by mass, the effect of preventing copper from diffusing into the second coating 4 is small. More preferably, the nickel content is 90% by mass or more.

The nickel-zinc alloy layer 7 has a film thickness of 0.1 μm or more and 5.0 μm or less. The content of zinc in the nickel-zinc alloy layer 7 is preferably 30% by mass or more and 95% by mass or less.
If the zinc content of the nickel-zinc alloy layer 7 is less than 30% by mass, the corrosion resistance of the nickel-zinc alloy layer 7 deteriorates, and the nickel-zinc alloy layer 7 quickly disappears from corrosion when exposed to a corrosive environment such as salt water. , and core wire 12a. On the other hand, if the zinc content of the nickel-zinc alloy layer 7 exceeds 95% by mass, the diffusion of zinc into the tin layer 8 becomes excessive, and the surface of the tin layer 8 tends to discolor.

Also, if the thickness of the nickel-zinc alloy layer 7 is less than 0.1 μm, the effect of lowering the corrosion potential of the surface (tin layer 8) of the second coating 4 is poor, and if it exceeds 5.0 μm, press workability decreases. Therefore, there is a risk that cracks may occur when the terminal 10 is pressed.

The tin layer 8 of the second coating 4 has a zinc concentration of 0.4% by mass or more and 15% by mass or less. As described above, when the tin layer 8 of the second coating 4 contains zinc, it has the effect of lowering the corrosion potential and preventing the core wire 12a made of aluminum from being corroded. If the zinc concentration of the tin layer 8 is less than 0.4% by mass, the corrosion potential becomes base and the effect of preventing corrosion of the core wire 12a is poor. If exposed, the tin layer 8 may be corroded, and the contact resistance between the second coating 4 and the core wire 12a may deteriorate. More preferably, the tin layer 8 has a zinc concentration of 1.5% by mass or more and 6.0% by mass or less.
Moreover, the film thickness of the tin layer 8 of the second film 4 is preferably 0.1 μm or more and 6.0 μm or less. If the thickness of the tin layer 8 is less than 0.1 μm, the thickness of the tin layer 8 is too thin, and it is difficult to form a uniform layer in manufacturing. There is a risk that it will be On the other hand, when the thickness of the tin layer 8 exceeds 6.0 μm, the thickness of the tin layer 8 is too thick, which causes an increase in the coefficient of dynamic friction on the surface of the second coating 4, resulting in a decrease in attachment/detachment resistance when used in a connector or the like. tends to increase. Moreover, it leads to an increase in material cost.

The second film 4 having the layer structure described above is present on the front and back surfaces of the portion excluding the core wire crimping portion 25 as described above. If an electrolytic liquid such as salt water adheres, there is a possibility that the portion other than the core wire crimping portion 25 may be electrically connected to the aluminum core wire 12a, and in the galvanic corrosion of dissimilar metals, a corrosion current may occur even from a distant portion. It is preferable to use the second film 4 in which the nickel-zinc alloy layer 7 is present because the nickel-zinc alloy layer 7 is present.

Next, a method for manufacturing the anticorrosive terminal material 1 will be described.
A plate material made of copper or a copper alloy is prepared as the base material 2 . By subjecting this plate material to processing such as cutting and punching, a strip material formed by connecting a plurality of terminal members 22 to a carrier portion 21 via connecting portions 23 is formed as shown in FIG. Then, the surface of the strip material is cleaned by degreasing, pickling, or the like.

By covering the area of the base material 2 other than the portion to be crimped 25 with a mask (not shown), only the portion 25 to be crimped is exposed, and the first film 3 is applied to the portion 25 to be crimped. Form. Although the method of forming each film including the first film 3 is not particularly limited, it is preferable to use an electrolytic plating method from the viewpoint of productivity. Besides the plating method, it is also possible to use a vapor deposition method or the like.

The plating bath for forming the first film 3 may be of any type as long as it can form a uniform film. If the first film 3 is a nickel-plated layer, a Watts bath, a sulfamic acid bath, a citric acid bath, or the like can be used. If the first film 3 is a copper-plated layer, a copper sulfate bath. a plating bath containing cobalt sulfate for a cobalt plating layer, and a plating bath containing manganese sulfate for a manganese plating layer.

Next, the mask covering the portion other than the portion to be crimped 25 is removed, and the portion to be crimped 25 is covered with the mask to expose the portion other than the portion 25 to be crimped. Nickel plating, nickel-zinc alloy plating, and tin plating are applied in order.
Nickel plating for forming the nickel layer 6 is not particularly limited as long as a dense nickel-based film can be obtained, and is formed by electroplating using a known sulfamic acid bath, Watt bath, citric acid bath, or the like. do it. The thickness of the nickel plating layer formed by this nickel plating is preferably 0.1 μm or more and 5.0 μm or less, more preferably 0.5 μm or more and 2.0 μm or less.

Nickel-zinc alloy plating for forming the nickel-zinc alloy layer 7 is not particularly limited as long as a dense film can be obtained with a desired composition, and electroplating using a sulfate bath, a chloride bath, or an alkali bath. can do. The film thickness of the nickel-zinc alloy plating layer formed by this nickel-zinc alloy plating is 0.1 μm or more and 5.0 μm or less, preferably 0.5 μm or more and 3.0 μm or less.

Tin plating or tin alloy plating for forming the tin layer 8 can be performed by a known method. Electroplating can be performed using an acidic bath such as an acid bath, a halogen bath, a sulfuric acid bath, a pyrophosphate bath, or an alkaline bath such as a potassium bath or sodium bath. The thickness of the tin-plated layer formed by this tin plating is preferably 0.1 μm or more and 6.0 μm or less, more preferably 0.5 μm or more and 3.0 μm or less.

In addition, in order to promote mutual diffusion between the nickel-zinc alloy layer 7 and the tin layer 8 at normal temperature (25° C.), the surface of the nickel-zinc alloy plating layer should be cleaned before the tin plating layer is laminated. Since hydroxides and oxides are rapidly formed on the surface of the nickel-zinc alloy plating layer, when continuously forming films by plating, an aqueous solution of sodium hydroxide or It is preferable to form a tin-plated layer immediately after washing with an aqueous solution of ammonium chloride. When the tin layer is formed by a dry method such as vapor deposition, the surface of the nickel-zinc alloy plated layer is preferably etched by argon sputtering before forming the tin layer.

In the anticorrosion terminal material 1 manufactured in this manner, the first film 3 containing the above specified element is formed on the portion 25 to be crimped on the core wire, and the nickel layer 6, A second film 4 consisting of a nickel-zinc alloy layer 7 and a tin layer 8 is formed.

Then, the strip material is processed into a terminal shape by press working or the like, and the connection portion 23 is cut, thereby forming the anticorrosive terminal 10 shown in FIG.
FIG. 4 shows a terminal portion structure in which the anti-corrosion terminal 10 is crimped to the electric wire 12, and the core wire crimping portion 13 and its vicinity come into direct contact with the core wire 12a of the electric wire 12. FIG.

This anti-corrosion terminal 10 has nickel, copper, cobalt, molybdenum, manganese, lead, iron, silver, gold, platinum, titanium, palladium, and antimony in the core wire crimping portion 25 , which is the inner surface portion of the core wire crimping portion 13 . Contains 60% by mass or more of any one or two or more of the designated elements, and since these designated elements form an intermetallic compound with aluminum, the adhesion in the cord crimping portion 25 is improved, The occurrence of galvanic corrosion of dissimilar metals can be suppressed.
A second film 4 is formed by laminating a nickel layer 6, a nickel-zinc alloy layer 7, and a tin layer 8 on the surface other than the portion 25 to be crimped. Since the tin layer 8 also contains zinc whose corrosion potential is close to that of aluminum, the corrosion potential of the tin layer 8 is close to that of aluminum. Therefore, the corrosion prevention effect is high in the vicinity of the core wire crimping portion 13 that contacts or is adjacent to the aluminum core wire 12a, and the progress of galvanic corrosion can be effectively prevented. Moreover, since the nickel-zinc alloy layer 7 is formed under the tin layer 8, even if all or part of the tin layer 8 disappears due to wear or the like, the underlying nickel-zinc alloy layer 7 remains intact. and the corrosion potential are close to each other, the progress of galvanic corrosion can be reliably suppressed.

In the present embodiment, since the strip material shown in FIG. 2 is plated, the base material 2 is not exposed on the end face of the anticorrosion terminal 10, so that an excellent anticorrosion effect can be exhibited.

[Second embodiment]
In the corrosion-resistant terminal material 1 of the first embodiment, the nickel layer 6, the nickel-zinc alloy layer 7, and the tin layer 8 are laminated in order as the second film 4 formed in the region other than the core wire crimping portion 25. , a nickel layer, a copper-tin alloy layer, and a tin layer may be laminated in this order. The first coating 3 is the same as that of the first embodiment. Therefore, since the cross-sectional layer structure of the corrosion-resistant terminal material of the second embodiment is the same as that shown in FIG. 1, illustration thereof is omitted. Such a terminal material can be used depending on the degree of corrosive environment.
The second film of the second embodiment is formed by sequentially applying nickel plating made of nickel or a nickel alloy, copper plating made of copper or a copper alloy, and tin plating made of tin or a tin alloy onto a base material, followed by heating and melting. A copper-tin alloy layer made of a copper-tin alloy such as Cu ₆ Sn ₅ or Cu ₃ Sn and a tin layer remaining unalloyed are formed on the nickel layer. The interface between the copper-tin alloy layer and the tin layer is uneven.

When manufacturing the corrosion-resistant terminal material of the second embodiment, first, the portion other than the portion to be crimped 25 of the base material 2 was exposed by covering the portion to be crimped 25 of the base material 2 with a mask (not shown). In this state, nickel plating, copper plating or copper alloy plating, and tin plating are applied in order, and finally the mask is removed and heat treatment is performed. After that, by covering the area other than the portion to be crimped 25 with a mask (not shown), only the portion 25 to be crimped is exposed, and the first film 3 is formed on the portion 25 to be crimped. .

Of these platings, nickel plating and tin plating may be performed under the same conditions as the nickel plating and tin plating in the first embodiment.
On the other hand, for copper plating, a general copper plating bath may be used, such as a copper sulfate bath containing copper sulfate (CuSO ₄ ) and sulfuric acid (H ₂ SO ₄ ) as main components. The film thickness of the copper plating layer formed by this copper plating is preferably 0.3 μm or more and 1.0 μm or less.

The heat treatment is carried out by raising the surface temperature of the substrate to 200° C. or higher and 270° C. or lower, holding the substrate at the temperature for 3 seconds or longer and 10 seconds or lower, and then rapidly cooling the substrate. By this heat treatment, the copper in the copper plating layer and the tin in the tin plating layer react to form a copper-tin alloy layer composed of the compound, and the remaining tin layer is disposed thereon. The interface between the copper-tin alloy layer and the tin layer is uneven.
This second film has a low coefficient of friction and is excellent as a connector terminal because the hard copper-tin alloy layer is arranged under the relatively soft tin layer via the uneven interface.
Although the nickel layer is provided as the second coating, the copper-tin alloy layer and the tin layer may be formed without forming the nickel layer, if necessary.

[Third Embodiment]
FIG. 5 shows a corrosion-proof terminal material 101 of the third embodiment.
This anti-corrosion terminal material 101 is the same as the first embodiment and the like in that the first film 3 made of the aforementioned specified element or its alloy is formed on the portion 25 to be crimped on the core wire. The second film 41 formed on the portion other than 25 has a tin layer 81 made of tin or a tin alloy formed on a nickel layer 61 made of nickel or a nickel alloy formed as necessary. Such a terminal material can be used depending on the degree of corrosive environment. The thickness of the tin layer 81 is preferably 0.1 μm or more and 6.0 μm or less.

The second film 41 having the tin layer 81 is formed by plating the base material 2 with nickel or a nickel alloy, or tin or a tin alloy, and then heat-melting (reflowing) it. It is formed by
The heat treatment is carried out by raising the surface temperature of the substrate 2 to 200° C. or more and 270° C. or less, holding the temperature for 3 seconds or more and 10 seconds or less, and then quenching.

In the anticorrosion terminal material 101, the second film 41 is made of so-called reflow tin, so that the tin layer 81 has a glossy surface and the internal stress is relieved to prevent the generation of whiskers.

[Fourth Embodiment]
FIGS. 6 to 8 show the anticorrosion terminal material of the fourth embodiment.
In the first to third embodiments, the film of the corrosion-resistant terminal material is divided into the core wire crimping planned portion 25 and the other regions. The region other than the planned portion 25 is further divided into two regions. A portion other than the portion to be linearly crimped 25 is defined as a surface exposed portion 27 .

In the case of the anti-corrosion terminal (female terminal) 100 of the embodiment shown in FIG. , the portion between the spring piece 11a and the top surface of the connection portion 11 and the upper half portion of the inner surface of the connection portion 11 in the inner surface of the connection portion 11 are the contact points that contact the male terminal 15. is.
As shown in FIG. 7, when the connecting portion 11 and the spring piece 11a are unfolded, the front surface of the portion that becomes the connecting portion 11 is indicated by the two-dot chain line, and the back surface of the spring piece 11a is partially indicated by the dashed line. These are the expected contact points 26 respectively.
The exposed surface portion 27 is the surface excluding the portion to be contacted 26 and the portion to be crimped 25 .

Then, as shown in FIG. 6 , the first film 3 is formed on the portion 25 to be crimped, and the second film 4 is formed on the exposed surface portion 27 . These first coating 3 and second coating 4 may be any combination of the coatings of the above embodiments. FIG. 7 shows the same combination of the first film 3 and the second film 4 as in the first embodiment.

On the other hand, the third film 5 is formed on the contact-provisioning portion 26 . The third film 5 is formed by forming a tin layer 82 made of tin or a tin alloy on a nickel layer 6 made of nickel or a nickel alloy formed as necessary. Even if the second coating 4 has the nickel-zinc alloy layer 7 and the tin layer 8 as in the first embodiment, the third coating 5 does not have the nickel-zinc alloy layer 7 . Even when the tin layer 82 is made of a tin alloy, it is preferable that the layer does not contain zinc. If zinc is present in the tin layer 81 on the surface of the third film 5, zinc oxide may be deposited in a high-temperature environment, resulting in loss of connection reliability as a contact. Therefore, in the third film 5 of the contact-proposed portion 26, the contact resistance can be increased even when exposed to a high-temperature environment by forming a structure that does not have a zinc layer. In addition, since the contact prospective portion 26 exists at a position separated from the core wire 12a, it is electrically connected through an electrolytic aqueous solution such as salt water, and is less likely to affect the corrosion reaction. In order to further reduce the possibility that the third film 5 of the prospective contact portion 26 affects the corrosion reaction, the narrower the prospective contact portion 26 without the zinc layer is, the better. In the example shown in FIG. 7, on the back surface of the spring piece 11a, the third film 5 is formed as the expected contact portion 26 only on the portion with which the male terminal 15 contacts.

The thickness of the nickel layer 6 of the third film 5 is preferably 0.1 μm or more and 5.0 μm or less, and the thickness of the tin layer 82 is preferably 0.1 μm or more and 6.0 μm or less. If the thickness of the tin layer 82 is less than 0.1 μm, it is difficult to form a uniform layer in manufacturing, and the plating may be broken during bending in the process of manufacturing terminals. On the other hand, when the film thickness of the tin layer 82 exceeds 6.0 μm, the film thickness is too thick, which causes an increase in the coefficient of dynamic friction, which tends to increase attachment/detachment resistance during use in a connector or the like. Moreover, it leads to an increase in material cost.

When manufacturing the corrosion-resistant terminal material of the fourth embodiment, first, nickel plating made of nickel or a nickel alloy for the third coating 5 in a state where the region other than the portion to be the contact portion 26 is covered with a mask, Tin plating consisting of tin or a tin alloy is applied in order. Next, by removing the mask and performing heat treatment, the third film 5 is formed on the contact prospective portion 26 . Next, the first film 3 is formed in a state in which the region other than the portion to be the core wire crimping portion 25 is covered with a mask. Next, the first film 3 and the third film 5 are covered with a mask, and nickel plating made of nickel or nickel alloy is applied. Then, plating for the second film 4 (for example, nickel-zinc alloy plating and tin plating made of tin or a tin alloy) is applied. Finally, the mask is removed, and the first film 3 is formed on the portion 25 to be crimped, the second film 4 is formed on the exposed surface portion 27, and the third film 5 is formed on the portion 26 to be contacted.
The heat treatment is carried out by raising the surface temperature of the substrate 2 to 200° C. or more and 270° C. or less, holding the temperature for 3 seconds or more and 10 seconds or less, and then quenching.

Since the surface of the third film 5 is formed of the tin layer 82, the anticorrosive terminal material 102 has good solder wettability and low contact resistance, and has excellent electrical properties. . In this case, since the third film 5 does not have a zinc layer under the tin layer 82, an increase in contact resistance can be suppressed even when exposed to a high-temperature environment.

As a method for forming the third film 5, after the first film 3 is formed, only the first film 3 is covered with a mask, for example, nickel plating and nickel-zinc alloy plating are sequentially applied, and then the contacts are planned by partial etching. After removing the nickel-zinc alloy plating layer of the portion 26, tin or tin alloy plating is applied to the entire surface, and finally the mask is removed and heat treatment is performed to form the second coating 4 and the third coating 5. good.

In addition, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, in the previous embodiment, various types of plating were applied to the pressed strip material. good.

A C1020 copper plate was used as the base material, and after degreasing and pickling the copper plate, a part of the plate was covered with a mask and plated with the specified elements shown in Table 1 to form the first film. The second coating shown in Table 1 was formed by covering the first coating with a mask and removing the mask from the portions other than the first coating. In addition, a part was also produced in which a third film was formed in place of the second film.

The following three types of plating films were used as the second film and the third film.
Plating A: The base material is plated with nickel to a thickness of 1.0 μm, and tin is plated thereon to a thickness of 1.5 μm, followed by heating at a temperature of 200° C. to 270° C. for 3 to 10 seconds. Heat treated.
Plating B: The substrate is plated with nickel to a thickness of 1.0 μm, copper is plated thereon to a thickness of 0.5 μm, and tin is plated thereon to a thickness of 1.5 μm. After that, heat treatment was performed at a temperature of 200° C. to 270° C. for 3 seconds to 10 seconds.
Plating C: The substrate is plated with nickel to a thickness of 1.0 μm, a nickel-zinc alloy is plated thereon to a thickness of 1.0 μm, and tin is plated to a thickness of 1.5 μm. was applied.

The main plating conditions were as follows, and the content of each additive metal element in each layer was adjusted by varying the amount of the additive metal element ions in the plating solution.
Further, as a comparative example, a tin-plated layer was used as the first film and a plating A was used as the second film.

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

<Nickel-zinc alloy plating conditions>
・Plating bath composition sodium sulfate 70g/L
Nickel sulfate 250g/L
Zinc sulfate 100g/L
Sulfuric acid 2g/L
・Anode: Nickel plate ・Bath temperature: 50°C
・Current density: 3 A/dm ²

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

<Copper plating conditions>
・Plating bath composition Copper sulfate pentahydrate 250g/L
Sulfuric acid 50g/L
・Bath temperature: 50℃
・Current density: 3 A/dm ²
・Anode: Phosphorus-containing copper

<Palladium plating conditions>
・Plating bath composition Palladium chloride 17g/L
Ammonium phosphate 100ml/L
Ammonium chloride 25g/L
・Bath temperature: 30℃
・Current density: 1 A/dm ²
・Anode: Pt/Ti (Insoluble electrode made by coating a titanium plate with platinum)

<Cobalt plating conditions>
・Plating bath composition Cobalt sulfate heptahydrate 140g/L
Boric acid 40g/L
・Bath temperature: 30℃
・Current density: 1 A/dm ²
・Anode: Pt/Ti

<Manganese plating conditions>
・Plating bath composition manganese sulfate 200g/L
Ammonium sulfate 100g/L
・Bath temperature: 30℃
・Current density: 8 A/dm ²
・Anode: Pt/Ti

<Silver plating conditions>
・Plating bath composition Potassium silver cyanide 55g/L
Potassium cyanide 130g/L
Potassium carbonate 15g/L
Nonionic surfactant 1g/L
2,2 thioethanol 5 g/L
・Bath temperature: 25℃
・Current density: 5 A/dm ²
・Anode: pure silver plate

<Nickel-cobalt alloy plating conditions>
・Plating bath composition Nickel sulfate hexahydrate 200g/L
Cobalt sulfate heptahydrate 10g/L
Boric acid 35g/L
・Bath temperature: 55℃
・Current density: 3 A/dm ²
・Anode: Nickel plate

<Copper-silver alloy plating conditions>
・Plating bath composition Potassium copper cyanide 50g/L
Potassium silver cyanide 2g/L
Potassium cyanide 5g/L
Potassium carbonate 20g/L
・Bath temperature: 30℃
・Current density: 0.3 A/dm ²
・Anode: silver plate and copper plate

<Lead plating conditions>
・Plating bath composition Lead methanesulfonate 50g/L
Methanesulfonic acid 150g/L
Brightener 1g/L
・Bath temperature: 30℃
・Current density: 1 A/dm ²
・Anode: lead plate

<Iron plating conditions>
・Plating bath composition Iron (II) sulfate heptahydrate 150g/L
Boric acid 30g/L
・Bath temperature: 40℃
・Current density: 1 A/dm ²
・pH = 2.0
・Anode: Iron plate

<Nickel molybdenum alloy plating conditions>
・Plating bath composition Nickel sulfate hexahydrate 20g/L
Sodium molybdate 40g/L
Trisodium citrate 70g/L
・Bath temperature: 40℃
・Current density: 4 A/dm ²
・pH = 5.0
・Anode: Nickel plate

<Gold plating conditions>
・Plating bath composition Potassium gold cyanide 5 g/L
Potassium cyanide 30g/L
Dipotassium hydrogen phosphate 30g/L
・Bath temperature: 60℃
・Current density: 0.3 A/dm ²
・Anode: Pt/Ti

<Platinum plating conditions>
・Plating bath composition Platinum chloride 5g/L
Hydrochloric acid 100g/L
Dipotassium hydrogen phosphate 30g/L
・Bath temperature: 60℃
・Current density: 3.5 A/dm ²
・Anode: Platinum plate

The film thickness of the first film and the concentration of the specified element were measured for the obtained samples.
The film thickness of the first coating was measured by observing the cross section with a scanning ion microscope.
In addition, the concentration of the designated element is determined by using a focused ion beam device: FIB (model number: SMI3050TB) manufactured by Seiko Instruments Inc. to prepare an observation sample by thinning the sample to 100 nm or less. Scanning transmission electron microscope manufactured by Co., Ltd.: STEM (model number: JEM-2010F) was used for observation at an acceleration voltage of 200 kV, and an energy dispersive X-ray analyzer attached to the STEM: EDS (manufactured by Thermo) was used. measured by The density was determined by averaging five values measured at equal intervals in the film thickness direction.

Table 1 shows combinations of the first to third coatings. As for the third coating, "-" indicates that the third coating was not provided and the second coating was formed in the region other than the portion 25 to be crimped. The column of concentration of the first coating shows the concentration of the designated element, and when the designated element consists of a plurality of elements, the elements and their contents are written together in the column of concentration. Also, in the column for the remainder of the first coating, the elements constituting the first coating other than the specified elements and inevitable impurities are described.

The obtained sample was formed into a female terminal and crimped with an aluminum core wire. As a corrosive environment exposure test, the terminal crimped with the aluminum core wire was immersed in a 5% sodium chloride aqueous solution at 23° C. for 24 hours and then left in a high temperature and high humidity environment of 75° C. and 90% RH for 48 hours. After that, the contact resistance between the aluminum core wire and the terminal was measured by the four-probe method. A current value was 10 mA.
Table 2 shows the results.

As can be seen from the results in Table 2, the examples in which the first coating containing the designated element was used exhibited a low contact resistance after the corrosive environment exposure test, exhibiting excellent anticorrosion properties. The sample using Plating C as the second coating had extremely low contact resistance. Since Plating C contains zinc, it is considered that zinc was appropriately diffused on the surface of the second film, thereby suppressing an increase in the contact resistance value.
On the other hand, in the comparative example, the contact resistance was high in the corrosive environment test because the first coating was a coating containing tin as the main component.

1, 101, 102 Corrosion-proof terminal material 2 Base material 3 First coatings 4, 41 Second coating 5 Third coatings 6, 61 Nickel layer 7 Nickel-zinc alloy layers 8, 81, 82 Tin layers 10, 100 Corrosion-proof terminal 11 Connection part 11a spring piece 12 electric wire 12a core wire (aluminum core wire)
12b Coating portion 13 Core wire crimping portion 14 Coating crimping portion 25 Core wire crimping portion 26 Contacting portion 27 Surface exposed portion

Claims (7)

A core wire crimping portion that is formed by forming a film on a base material made of metal and becomes the inner surface of the portion to which the core wire of the electric wire is crimped when formed into a terminal, and a portion other than the core wire crimping portion. Among the coatings, the first coating formed on the portion to be crimped on the core wire includes nickel, copper, cobalt, molybdenum, manganese, lead, iron, silver, gold, platinum, titanium, palladium, and antimony. or an alloy thereof, and a second film having a tin layer made of tin or a tin alloy is formed on the surface of the portion other than the portion to be crimped. material. 2. The anti-corrosion terminal material for an aluminum core wire according to claim 1, wherein the film thickness of said first film is 0.1 [mu]m or more and 8.0 [mu]m or less. 3. The anti-corrosion terminal material for an aluminum core wire according to claim 1, wherein the second coating comprises the tin layer formed on the nickel-zinc alloy layer. A third film is formed in place of the second film on a portion to be a contact that becomes a contact when molded into a terminal, and the surface of the third film is formed of the tin layer and the nickel-zinc alloy layer. The anti-corrosion terminal material for an aluminum core wire according to claim 3, characterized in that it does not have An anti-corrosion terminal for an aluminum core wire, comprising the anti-corrosion terminal material for an aluminum core wire according to any one of claims 1 to 4. 6. An electric wire end portion structure, wherein the anti-corrosion terminal according to claim 5 is crimped to the end of an electric wire comprising an aluminum core wire of aluminum or an aluminum alloy. 7. An electric wire end structure according to claim 6, wherein an intermetallic compound is formed in a state where said corrosion-proof terminal and said aluminum core wire are in contact with each other.

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