JP6812852B2 - Anti-corrosion terminal material, anti-corrosion terminal, and electric wire terminal structure - Google Patents

Description

The present invention relates to an anticorrosion terminal material which is used as a terminal to be crimped to an electric wire terminal made of an aluminum wire and is less likely to cause electrolytic corrosion, an anticorrosion terminal made of the terminal material, and an electric wire terminal portion structure using the terminal.

Conventionally, a terminal made of copper or a copper alloy is crimped to a terminal part of an electric wire made of copper or a copper alloy, and this terminal is connected to a terminal provided in the device to connect the electric wire to the device. The connection is being made. Further, in order to reduce the weight of the electric wire, the core wire 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 electric wire for an automobile wire harness made of an aluminum alloy.

By the way, if the electric wire (lead wire) is made of aluminum or an aluminum alloy and the terminal is made of copper or a copper alloy, electrolytic corrosion occurs due to the potential difference between different metals when water enters the crimping portion between the terminal and the electric wire. Sometimes. Then, as the electric wire is corroded, the electric resistance value at the crimping portion may increase or the crimping force may decrease.

As a method for preventing this corrosion, for example, there are those described in Patent Document 2 and Patent Document 3.
Patent Document 2 describes at least a bare metal portion 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. It is composed of an intermediate layer partially provided thinly by plating and a third metal material having a smaller standard electrode potential value than the second metal material, and is provided thinly by plating at least a part of the surface of the intermediate layer. A terminal having a surface layer is disclosed. Copper or this alloy is described as the first metal material, lead or this alloy, or tin or this alloy, nickel or this alloy, zinc or this alloy is described as the second metal material, and the third metal material is Aluminum or this alloy is described.

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

Japanese Unexamined Patent Publication No. 2004-134212 Japanese Unexamined Patent Publication No. 2013-33656 Japanese Unexamined Patent Publication No. 2011-222243

However, although corrosion can be prevented by the structure described in Patent Document 3, 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 in the terminal cross-sectional area due to the resin. Since an ionic liquid or the like is used to carry out the aluminum-based plating which is the third metal material described in 2, there is a problem that it is very costly.

The present invention has been made in view of the above-mentioned problems, and uses a copper or copper alloy base material as a terminal to be crimped to the terminal of an electric wire having an aluminum core wire, and an anticorrosion terminal material which is less likely to cause electrolytic corrosion and the terminal material thereof. It is an object of the present invention to provide an anticorrosion terminal made of a terminal material and an electric wire terminal portion structure using the terminal.

In the anticorrosion terminal material of the present invention, a film is laminated on a base material made of copper or a copper alloy, and a contact point with a core wire contact portion to which the core wire of the electric wire is contacted when formed into a terminal. A contact portion to be a contact portion is formed, and the film formed on the core wire contact schedule portion includes a zinc-nickel alloy layer containing zinc and nickel, a tin layer made of tin or a tin alloy, and a metal. and zinc layer are laminated in this order, wherein the film to be formed on the contact portions to be, the zinc-nickel alloy layer, the tin layer, of the metal zinc layer has a pre Kisuzuso, said zinc It does not have a nickel alloy layer and the metallic zinc layer.

In this anticorrosion terminal material, a metallic zinc layer is formed at the planned core wire contact portion, and since the corrosion potential of this metallic zinc is close to that of aluminum, the occurrence of electrolytic corrosion when contacting the aluminum core wire is suppressed. be able to. Moreover, since it has a zinc-nickel alloy layer as a base and the zinc diffuses to the surface of the tin layer, the metallic zinc layer is maintained at a high concentration. Even if all or part of the metallic 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 underneath.
On the other hand, if the metallic zinc layer is present on the surface of the tin layer, the connection reliability may be impaired in a high temperature and high humidity environment. For this reason, it is possible to suppress an increase in contact resistance even when exposed to a high-temperature and high-humidity environment by adopting a structure in which only the planned contact portion does not have a metallic zinc layer. In the contact portion to be, not zinc-nickel alloy layer beneath the tin layer in order to suppress the reduction in connection reliability due to the diffusion of zinc from the underlying not exist.

In the anticorrosion terminal material of the present invention, the metal zinc layer preferably has a coverage of 30% or more and 80% or less on the surface after being molded as a terminal.

The metallic zinc layer does not exist in the planned contact portion, but must exist in the core wire contact scheduled portion. The portion other than these does not necessarily have to be present, but it is desirable that the ratio of the portion where the metallic zinc layer is present is high, and it is preferable that the portion has a coverage of 30% or more and 80% or less of the entire surface.

In the anticorrosion terminal material of the present invention, the metallic zinc layer preferably has a zinc concentration of 5 at% or more and 40 at% or less and a thickness of 1 nm or more and 10 nm or less in terms of SiO ₂ .

If the zinc concentration of the metallic zinc layer is less than 5 at%, the effect of lowering the corrosion potential is poor, and if it exceeds 40 at%, the contact resistance may deteriorate. If the SiO ₂ equivalent thickness of the metallic zinc layer 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.

In the anticorrosion terminal material of the present invention, the zinc-nickel alloy layer preferably has a nickel content of 5% by mass or more and 35% by mass or less.

If the nickel content in the zinc-nickel alloy layer is less than 5% by mass, a substitution reaction may occur during tin plating for forming the tin layer, and the adhesion of the tin plating may decrease. If it exceeds 35% by mass, the effect of lowering the corrosion potential on the surface becomes poor.

In the anticorrosion terminal material of the present invention, the tin layer at the planned core wire contact portion is preferably made of a tin alloy containing 0.4% by mass or more and 15% by mass or less of zinc.

When the tin layer contains zinc, it has the effect of lowering the corrosion potential and preventing corrosion of the aluminum core wire, but when the zinc concentration is less than 0.4% by mass, the anticorrosion effect is poor, and when it exceeds 15% by mass, the effect is poor. The corrosion resistance of the tin layer is reduced, and when exposed to a corrosive environment, the tin layer may be corroded and the contact resistance may deteriorate.

In the anticorrosion terminal material of the present invention, it is preferable that a base layer made of nickel or a nickel alloy is formed between the base material and the zinc-nickel alloy layer.

The base layer between the base material and the zinc-nickel alloy layer has the effect of suppressing copper from diffusing from the base material to the surface of the film when a heat load is applied, thereby increasing the contact resistance.

Further, in the anticorrosion terminal material of the present invention, a terminal member having the core wire contact planned portion and the contact scheduled portion is formed in the carrier portion in the carrier portion along the length direction of the strip plate. Multiple pieces are connected at intervals in the length direction.
The anticorrosion terminal of the present invention is a terminal made of the above-mentioned anticorrosion terminal material, and in the electric wire terminal portion structure of the present invention, the anticorrosion terminal is crimped to the terminal of an electric wire made of aluminum or an aluminum alloy.

According to the present invention, since a metallic zinc layer having a corrosion potential close to that of aluminum is formed on the surface of the planned core wire contact portion, it is possible to suppress the occurrence of electrolytic corrosion when the core wire is in contact with the aluminum core wire. Since zinc diffuses from the zinc-nickel alloy layer under the tin layer to the surface part of the tin layer, the metallic zinc layer can be maintained at a high concentration, and it has excellent long-term corrosion resistance. 1. Even if all or part of the tin layer disappears due to wear, etc., the zinc-nickel alloy layer underneath can suppress the occurrence of electrolytic corrosion, resulting in an increase in electrical resistance and a decrease in pressure on the core wire. Can be suppressed. On the other hand, since there is no metallic zinc layer in the planned contact portion, it is possible to suppress an increase in contact resistance even when exposed to a high temperature and high humidity environment.

It is sectional drawing which shows typically the embodiment of the anticorrosion terminal material of this invention. It is a top view of the anticorrosion terminal material of an embodiment. It is a perspective view which shows the example of the terminal to which the anticorrosion terminal material of an embodiment is applied. It is a front view which shows the terminal part of the electric wire which crimped the terminal of FIG. It is a micrograph of the cross section of the terminal material of the sample 10. It is a micrograph of the cross section of the terminal material of the sample 12. FIG. 5 is a concentration distribution diagram of each element in the depth direction by XPS analysis on the surface portion of the terminal material of Sample 9. It is a chemical state analysis chart in the depth direction in the surface part of the terminal material of the sample 7, (a) is an analysis chart about tin, (b) is zinc. It is a graph which measured the galvanic corrosion progress of each of the terminal material of sample 7, the terminal material of sample 12, and the copper terminal material without plating.

The structure of the anticorrosion terminal material, the anticorrosion terminal, and the electric wire terminal portion according to the embodiment of the present invention will be described.
As shown as a whole in FIG. 2, the anticorrosion terminal material 1 of the present embodiment is a hoop material formed in a strip shape for molding a plurality of terminals, and is a hoop material formed on both sides thereof along the length direction. A plurality of terminal members 22 to be molded as terminals are arranged between the formed carrier portions 21 at intervals in the length direction of the carrier portions 21, and the terminal members 22 form a narrow connecting portion 23. It is connected to the carrier portion 21 via the carrier portion 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 shows a female terminal in the example of FIG. 3, and a core in which a connecting portion 11 into which a male terminal 15 (see FIG. 4) is fitted and an exposed core wire 12a of an electric wire 12 are crimped from the tip. The wire crimping portion 13 and the covering crimping portion 14 to which the covering portion 12b of the electric wire 12 is crimped are integrally formed in this order. The connecting portion 11 is formed in a square cylinder shape, and a spring piece 11a continuous from the tip thereof is inserted so as to be folded (see FIG. 4).
FIG. 4 shows a terminal portion structure in which the anticorrosion terminal 10 is crimped to the electric wire 12, and the vicinity of the core wire crimping portion 13 comes into direct contact with the core wire 12a of the electric wire 12.
In the hoop material described above, in the portion that becomes the connection portion 11 when formed into the anticorrosion terminal 10, the portion that contacts the male terminal 15 and becomes the contact portion is the contact portion 25, and the core wire 12a is located near the core wire crimping portion 13. The surface of the contacted portion is designated as the core wire contact scheduled portion 26.
In this case, the planned contact portion 25 is formed on the inner surface of the connecting portion 11 formed in a square cylinder shape and the facing surface of the spring piece 11a folded in the connecting portion 11 in the female terminal of the embodiment. Will be done. In the expanded state of the connecting portion 11, the front surfaces of both side portions of the connecting portion 11 and the back surface of the spring piece 11a are the scheduled contact portions 25.

Then, as the cross section (corresponding to the cross section along the line AA of FIG. 2) is schematically shown in FIG. 1, the anticorrosion terminal material 1 has a film 8 on a base material 2 made of copper or a copper alloy. On the surface of the portion of the film 8 other than the planned contact portion 25, a base layer 3 made of nickel or a nickel alloy, a zinc-nickel alloy layer 4, and a tin layer 5 are laminated in this order, and further. , A metallic zinc layer 7 is formed on the tin layer 5 and under 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 metallic zinc layer 7 are not provided. It is desirable that the metallic zinc layer 7 exists at a coverage of 30% or more and 80% or less of the surface (the surface of the terminal member 22) after being molded as the terminal 10.

The composition of the base material 2 is not particularly limited as long as it is made of copper or a copper alloy.
Hereinafter, with respect to the film 8, first, the portion excluding the planned contact portion 25 (including the scheduled core wire contact portion 26) will be described for each layer.
The base layer 3 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. The base layer 3 has a function of preventing the diffusion of copper from the base material 2 to the zinc-nickel alloy layer 4 and the tin layer 5, and if the thickness is less than 0.1 μm, the effect of preventing the diffusion of copper is poor. If it exceeds 0.0 μm, cracks are likely to occur during press working. The thickness of the base layer 3 is more preferably 0.3 μm or more and 2.0 μm or less.
Further, if 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 a thickness of 0.1 μm or more and 5.0 μm or less, and 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 on the surface is poor, and if it exceeds 5.0 μm, cracks may occur during press working on 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.
If the nickel content of the zinc-nickel alloy layer 4 is less than 5% by mass, a substitution reaction occurs during 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 on 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 and does not exist 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% by mass or more and 15% by mass or less. If the zinc concentration of the tin layer 5 is less than 0.4% by mass, the effect of lowering the corrosion potential and preventing corrosion of the aluminum wire is poor, and if it exceeds 15% by mass, the corrosion resistance of the tin layer 5 is significantly reduced, so that the tin layer 5 is exposed to a corrosive environment. If this is done, the tin layer 5 may be corroded and the 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.
The thickness of the tin layer 5 is preferably 0.1 μm or more and 10 μm or less. If it is too thin, the solder wettability may be lowered and the contact resistance may be lowered. If it is too thick, the dynamic friction coefficient of the surface may be increased and the connector There is a tendency for the attachment / detachment resistance to increase when used in such cases.

The metallic zinc layer 7 has a zinc concentration of 5 at% or more and 40 at% or less and a thickness of 1 nm or more and 10 nm or less in terms of SiO ₂ . If the zinc concentration of this metallic 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 metallic zinc layer 7 is more preferably 10 at% or more and 25 at% or less.
On the other hand, if the thickness of the metal zinc layer 7 in terms of SiO ₂ 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 thickness is more preferably 1.25 nm or more and 3 nm or less.
An oxide layer 6 of zinc or tin is formed on the surface of the metallic zinc layer 7.

As described above, the film 8 having the above layer structure exists on the surface of the portion other than the planned contact portion 25. As described above, it is desirable that the film 8 having the metallic zinc layer 7 has a coverage of 30% or more and 80% or less of the surface when molded 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 nickel alloy are present. The composition, film thickness, and the like of each of the base layer 3 and the tin layer 5 are the same as those constituting the film 8 existing on the surface of the portion other than the planned contact portion 25.

Next, a method for manufacturing the anticorrosion terminal material 1 will be described.
As the base material 2, a plate material made of copper or a copper alloy is prepared. By performing processing such as cutting and drilling on this plate material, a plurality of terminal members 22 are formed into a hoop material formed by being connected to the carrier portion 21 via the connecting portion 23 as shown in FIG. Then, the surface of this hoop material is cleaned by degreasing, pickling, or the like, and then nickel or nickel alloy plating for forming the base layer 3 is applied to the entire surface of the hoop material. It is covered with a mask (not shown), and in that state, zinc-nickel alloy plating is applied to form the zinc-nickel alloy layer 4, the mask is removed, and tin or tin alloy plating is applied to the entire surface to form the tin layer 5. ..

The nickel or nickel alloy plating for forming the base layer 3 is not particularly limited as long as a dense nickel-based film can be obtained, and electroplating is performed using a known watt bath, sulfamic acid bath, citric acid bath, or the like. Can be formed by Nickel alloy plating includes 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, etc. Nickel zinc (Ni—Zn) alloy, nickel boron (Ni—B) alloy and 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 the sulfamic acid bath is desirable.

The zinc-based 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 is known as a sulfate bath, a chloride salt bath, a neutral bath, or the like. Can be used.

The tin or tin alloy plating for forming the tin layer 5 can be carried out 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 pyrophosphate bath, or an alkaline bath such as a potassium bath or a sodium bath.

In this way, the base material 2 is plated and then heat-treated.
In this heat treatment, the surface temperature of the material is 30 ° C. or higher and 190 ° C. or lower. By this heat treatment, zinc in the zinc-based alloy plating layer is diffused in the tin plating layer and on the tin plating layer in the portion other than the planned contact portion 25, and a thin metallic zinc layer is formed on the surface. Since the diffusion of zinc 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 repellent portion in the tin layer 5, it is not heated to a temperature exceeding 190 ° C.

In the anticorrosion terminal material 1 produced in this manner, a base layer 3 made of nickel or a nickel alloy is formed on the base material 2, and the contact portion 25 covered with a mask is above the base layer 3. A zinc layer 5 is formed in the base layer 5, and a zinc-based alloy layer 4, a tin layer 5, and a metallic zinc layer 7 are formed on the base layer 3 in a portion other than the planned contact portion 25, and the surface of the metallic zinc layer 7 is formed. The oxide layer 6 is formed thinly.
Then, the hoop material is processed into the shape of the terminal shown in FIG. 3 by press working or the like, and the connecting portion 23 is cut to form the anticorrosion terminal 10.
FIG. 4 shows a terminal portion structure in which the terminal 10 is crimped to the electric wire 12, and the vicinity of the core wire caulking portion 13 comes into direct contact with the core wire 12a of the electric wire 12.

The anticorrosion terminal 10 is made of aluminum because the tin layer 5 contains zinc in the core wire contact portion 26 and the metallic zinc layer 7 is formed under the oxide layer 6 on the outermost surface of the tin layer 5. Even in the state of being crimped to the core wire 12a, since the corrosion potential of metallic zinc is very close to that of aluminum, it is possible to prevent the occurrence of electrolytic corrosion. In this case, since the base material 2 is not exposed on the end face of the terminal 10 because the hoop material of FIG. 2 is plated and heat-treated, an excellent anticorrosion effect can be exhibited.
Moreover, since the zinc-nickel alloy layer 4 is formed under the tin layer 5 and the zinc diffuses to the surface portion of the tin layer 5, the disappearance of the metallic zinc layer 7 due to wear or the like is suppressed, and the metallic zinc is suppressed. Layer 7 is maintained at a high concentration. Further, even if all or a part of the tin layer 5 disappears due to wear or the like, the zinc-nickel alloy layer 4 under the tin layer 5 has a corrosion potential close to that of aluminum, so that the occurrence of electrolytic corrosion can be suppressed.

On the other hand, if the metallic zinc layer 7 is present on the surface of the tin layer 5, the connection reliability may be impaired in a high temperature and high humidity environment. However, in this embodiment, the metallic zinc layer 7 is formed on the planned contact portion 25. By adopting a structure that does not have zinc, it is possible to suppress an increase in contact resistance even when exposed to a high temperature and high humidity environment.

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.
For example, in the embodiment, as a method of not forming the metallic zinc layer 7 on the planned contact portion 25, in the embodiment, zinc-nickel alloy plating or the like is performed with the planned contact portion 25 covered with a mask, but the planned contact portion 25 is formed. A method may be used in which zinc-nickel alloy plating is applied to the entire surface including the zinc-nickel alloy, and the zinc-nickel alloy plating layer of the planned contact portion 25 is removed by partial etching.
Further, although the metallic zinc layer 7 on the surface is formed by diffusion from the zinc-based alloy layer 4 in the portion other than the planned contact portion 25, the metallic zinc layer 7 may be formed on the surface of the tin layer 5 by galvanizing. .. This zinc plating can be performed by a known method, and for example, electroplating can be performed using a zincate bath, a sulfate bath, a zinc chloride bath, or a cyanide bath. In this case, it is preferable that the zinc-nickel alloy layer 4 does not exist in the planned contact portion 25, but it may exist.

The copper plate of the base material was punched into the hoop material shown in FIG. 2, degreased and pickled, and then zinc-nickel alloy plating was applied except for the planned contact portion 25 of FIG. Further, after that, tin plating is performed on the entire surface, and 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 to form the metallic zinc layer 7. , An anticorrosion terminal material 1 having a metallic zinc layer 7 in a portion other than the planned contact portion 25 was obtained.
As a comparative example, a metal-zinc layer 7 is formed on the planned contact portion 25 by plating the entire surface with zinc-nickel alloy plating without covering the planned contact portion 25 with a mask (Sample 11), and the planned contact portion 25. A copper plate was degreased, pickled, and then nickel-plated and then tin-plated in that order (Sample 12) without performing zinc-based alloy plating including the parts other than the above.

The conditions for each plating were as follows, and the nickel content of the zinc-nickel alloy plating was adjusted by varying the ratio of nickel sulfate hexahydrate and zinc sulfate heptahydrate. The zinc-nickel alloy plating conditions below are examples in which the nickel content is 15% by mass. Further, although the samples 1 to 9 were not nickel-plated as the base layer 3, the sample 10 was nickel-plated to form the base layer 3.

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

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

With respect to the obtained sample, the nickel content in the zinc-nickel alloy layer 4, the zinc concentration in the tin layer 5, the thickness and zinc concentration in the metallic zinc layer 7, and the coverage of the metallic zinc layer 7 were measured.
For the nickel content of the zinc-nickel alloy layer 4, an observation sample was prepared by diluting the sample to 100 nm or less using a focused ion beam device: FIB (model number: SMI3050TB) manufactured by Seiko Instruments Co., Ltd., and this observation sample was prepared. The energy dispersive X-ray analyzer attached to STEM: EDS (manufactured by Thermo) was observed at an acceleration voltage of 200 kV using a scanning transmission type electron microscope: STEM (model number: JEM-2010F) manufactured by Nippon Denshi Co., Ltd. ) Was used for measurement.
The zinc concentration in the tin layer 5 was measured on the sample surface using an electron probe microanalyzer manufactured by JEOL Ltd .: EPMA (model number JXA-8530F) with an acceleration voltage of 6.5 V and a beam diameter of φ30 μm.

Regarding the thickness and zinc concentration of the metallic zinc layer 7, for each sample, the sample surface was etched with argon ions using an XPS (X-ray Photoelectron Spectroscopy) analyzer: ULVAC PHI model-5600LS manufactured by ULVAC-PHI, Inc. However, it was measured by XPS analysis. The analysis conditions are as follows.
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 the sample surface: 45 deg
Analysis area: Approximately 800 μmφ

Regarding the thickness, the “SiO ₂ equivalent film thickness” was calculated from the time required for the measurement using the etching rate of SiO ₂ measured in advance with the same model.
The etching rate of SiO ₂ is calculated by etching a SiO ₂ film having a thickness of 20 nm with argon ions in a rectangular region of 2.8 × 3.5 mm and dividing by the time required to etch 20 nm. Calculated. In the case of the above analyzer, it took 8 minutes, so the etching rate was 2.5 nm / min. XPS has an excellent depth resolution of about 0.5 nm, but the etching time with an Ar ion beam differs depending on each material. Therefore, in order to obtain the numerical value of the film thickness itself, a sample with a known film thickness is procured. And the etching rate must be calculated. Since the above is not easy, the etching rate calculated for the SiO ₂ film whose film thickness is known is specified, and the "SiO ₂ equivalent film thickness" calculated from the time required for etching is used. Therefore, it should be noted that the "SiO ₂ equivalent film thickness" is different from the actual oxide film thickness. If the film thickness is defined by the SiO ₂ equivalent etching rate, even if the actual film thickness is unknown, the film thickness can be quantitatively evaluated because it is unique.
The SiO ₂ equivalent film thickness is the film thickness of the portion where the metallic zinc concentration is equal to or higher than a predetermined value, and even if the metallic zinc concentration can be partially measured, the layer is extremely thinly dispersed. May not be measurable as the SiO ₂ equivalent film thickness.
The results of these measurements are shown in Table 1. In Table 1, it is shown that the SiO ₂ equivalent film thickness of the metallic zinc layers of Samples 1 to 11 could not be measured.

The obtained sample was molded into a 090 type terminal and crimped with a pure aluminum wire. After the terminals crimped with this pure aluminum wire are left in a corrosive environment, a high temperature and high humidity environment, and a high heat environment, the contact resistance between the aluminum wire and the terminals, or the contact resistance between the terminals when the terminals are fitted together, is measured. It was measured.
<Corrosive environment leaving 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 at 85 ° C. and 85% RH under high temperature and high humidity for 24 hours. Then, the contact resistance between the aluminum wire and the terminal was measured by the four-terminal method. The current value was 10 mA.
<High temperature and high humidity environment test>
A 090 type female terminal crimped with a pure aluminum wire was left at 85 ° C. and 85% RH for 96 hours. Then, the contact resistance between the aluminum wire and the terminal was measured by the four-terminal method. The current value was 10 mA.
<High heat environment leaving test>
The terminals crimped with pure aluminum wire were left at 150 ° C. for 500 hours. Then, 090 type tin-plated male terminals were fitted and the contact resistance between the terminals was measured by the four-terminal method.
These results are shown in Table 2.

FIG. 5 is an electron micrograph of a cross section of the sample 10 at the core wire contact portion, and it can be confirmed that the base layer (nickel layer), the zinc-nickel alloy layer, and the tin layer are formed from the base material side. The outermost surface of the tin layer cannot be identified. On the other hand, FIG. 6 is an electron micrograph of a cross section of the core wire contact portion of the sample 12 and does not have a zinc-nickel alloy layer.

FIG. 7 is a concentration distribution diagram of each element in the depth direction on the surface portion of the surface portion of the core wire contact portion of the sample 9 by XPS analysis, and the metallic zinc layer having a zinc concentration of 5 at% to 43 at% is 5 in terms of SiO ₂ thickness. It is present at 0.0 nm and has a zinc concentration of 22 at%. The zinc concentration of the metallic zinc layer was taken as the average value of the zinc concentration in the thickness direction of the portion where 5 at% or more of metallic zinc was detected by XPS. The zinc concentration of the metallic zinc layer in the present invention is an average value of the zinc concentration in the thickness direction of the portion where 5 at% or more of metallic zinc is detected by XPS analysis.

FIG. 8 is a chemical state analysis diagram in the depth direction at the core wire contact portion of the sample 7. From the chemical shift of the binding energy, it can be determined that the depth from the outermost surface to 1.25 nm is mainly oxide, and after 2.5 nm it is mainly metallic zinc.

From these results, it can be seen that the portion where the aluminum core wire comes into contact has a metallic zinc layer formed on the surface thereof, and thus has excellent corrosion resistance. Among the samples 4 to 10 in which the zinc concentration of the metallic zinc layer is 5 at% or more and 40 at% or less and the SiO ₂ equivalent thickness is 1 nm or more and 10 nm or less, the contact resistance after the corrosive environment leaving test is higher than that of samples 1 to 3. It was low. In particular, Sample 10 having a nickel base layer between the base material and the zinc-nickel alloy layer has the best corrosion resistance among Samples 1 to 10.
On the other hand, since the sample 11 of the comparative example had a metallic zinc layer at the contact portion, the contact resistance increased in the tests of high temperature and high humidity leaving and high heat leaving. Further, since the sample 12 did not have a metallic zinc layer at the core wire contact portion, severe corrosion was observed in the corrosive environment leaving test, and the contact resistance was remarkably increased.

Note that FIG. 9 shows the measurement results of the corrosion current at the core wire contact portion of the sample 7 and the sample 12. For reference, the values are also shown for the terminal material of oxygen-free copper (C1020) that is not plated. The larger the positive value of the corrosion current, the more galvanic corrosion is applied to the aluminum wire. As shown in FIG. 9, it can be seen that the sample 7 of the example has a small corrosion current and can suppress the occurrence of electrolytic corrosion.

1 Anticorrosion terminal material 2 Base material 3 Base layer 4 Zinc nickel alloy layer 5 Tin layer 6 Oxide layer 7 Metallic zinc layer 10 Terminal 11 Connection part 12 Electric wire 12a Core wire 12b Coating part 13 Core wire crimping part 14 Coating crimping part 25 Contact Scheduled part 26 Core line contact Scheduled part

Claims (9)

A film is laminated on a base material made of copper or a copper alloy, and a core wire contact portion that is in contact with the core wire of the electric wire when formed into a terminal and a contact schedule portion that is a contact portion are The film formed at the planned core wire contact portion is formed by laminating a zinc-nickel alloy layer containing zinc and nickel, a tin layer made of tin or a tin alloy, and a metallic zinc layer in this order. and, wherein the film to be formed on the contact portions to be, the zinc-nickel alloy layer, the tin layer, among the metallic zinc layer, before have Kisuzuso, the zinc-nickel alloy layer and the metallic zinc layer Anti-corrosion terminal material characterized by not having. The anticorrosion terminal material according to claim 1, wherein the metallic zinc layer has a coverage of 30% or more and 80% or less on the surface after being molded as a terminal. The anticorrosion terminal material according to claim 1 or 2, wherein the metallic zinc layer has a zinc concentration of 5 at% or more and 40 at% or less and a thickness of 1 nm or more and 10 nm or less in terms of SiO2. The anticorrosion terminal material according to any one of claims 1 to 3, wherein the zinc-nickel alloy layer has a nickel content of 5% by mass or more and 35% by mass or less. The anticorrosion terminal material according to any one of claims 1 to 4, wherein the tin layer at the planned core wire contact portion is made of a tin alloy containing 0.4% by mass or more and 15% by mass or less of zinc. The anticorrosion terminal material according to any one of claims 1 to 5, wherein a base layer made of nickel or a nickel alloy is formed between the base material and the zinc-nickel alloy layer. A plurality of terminal members having the core wire contact planned portion and the contact scheduled portion are connected to the carrier portion formed in a strip shape and along the length direction at intervals in the length direction of the carrier portion. The anticorrosion terminal material according to any one of claims 1 to 6, wherein the anticorrosion terminal material is provided. An anticorrosion terminal comprising the anticorrosion terminal material according to any one of claims 1 to 7. The electric wire terminal portion structure according to claim 8, wherein the anticorrosion terminal is crimped to the terminal of an electric wire made of aluminum or an aluminum alloy.

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