JP2003328157A - Plated material, production method thereof and electrical and electronic parts obtained by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plated material which combines satisfactory heat resistance and inserting/extracting properties. <P>SOLUTION: An undercoat layer 2 consisting of any one kind selected from Fe or an Fe alloy, Ni or an Ni alloy, and Co or a Co alloy, the first intermediate plating layer 3 consisting of Sn or an Sn alloy, the second intermediate plating layer 4 consisting of Cu or a Cu alloy and a surface plating layer 5 consisting of Sn or an Sn alloy are formed on the surface of an electrically conductive substrate 1 in this order. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating material, a method for producing the same, and electric / electronic parts using the plating material. More specifically, the present invention relates to a plating material which has good heat resistance and is suitable as a material for a connector used in a high temperature environment such as an automobile engine room. Further, the present invention relates to a plating material suitable as a material for a fitting type connector or a contactor used in a high temperature environment because it has both good heat resistance and insertability / extractability.

[0002]

2. Description of the Related Art A material in which a plating layer made of Sn or Sn alloy is provided on a conductive base material made of Cu or Cu alloy is
It is known as a high-performance conductor having excellent conductivity and strength of a base material and good electrical contact characteristics, corrosion resistance, and solderability of Sn or Sn alloy. This material is widely used for various terminals and connectors.

As such a material, there is usually used a material produced by subjecting a base material to an undercoat of Cu or Ni and then directly plating an Sn or Sn alloy thereon. There is. This base plating layer has a base material component (alloy component such as Cu or Zn) of Sn or S on the surface.
It is provided in order to suppress thermal diffusion to the n alloy. In particular, when the base plating layer is a plating layer made of Ni or a Ni alloy, the effect of delaying the above-mentioned thermal diffusion to Sn or the Sn alloy on the surface is great even in a high temperature environment. Therefore, the characteristics of Sn or Sn alloy on the surface can be secured for a long time.

However, even in the case of the above-mentioned material having the undercoat layer of Ni or Ni alloy, the following problems occur. For example, when it is used in a particularly high temperature place such as in the vicinity of an engine in an engine room of an automobile, Cu of the base material, Ni of the base material, and Ni alloy of the base material also thermally diffuse to the surface plating layer side with time. After a certain period of time, the surface plating layer is not the original Sn or Sn alloy, and the surface plating layer made of Sn or Sn alloy disappears in effect. As a result, the plating material will not exhibit its original performance.

Such a problem can be solved by increasing the thickness of the surface plating layer made of Sn or Sn alloy to prolong the disappearance time of the surface plating layer.
However, such countermeasures waste resources.
Moreover, not only that, but when the plating material is used in, for example, a multi-pole fitting type connector, since the thickness of Sn or Sn alloy is large, the frictional force at the time of fitting becomes large,
This may cause a new problem that the assembling work becomes difficult.

By the way, in the fitting type connector, the male terminal and the female terminal are fitted to each other for electrical connection. In recent years, with regard to connector terminals mounted on automobiles, the amount of transmission information is increasing and electronic control is progressing. Along with that, the number of poles of connectors is increasing. In that case, since the number of contacts to be fitted increases as the number of poles of the connector increases, it is strongly demanded that the insertion force at the time of fitting be reduced for the connector having a lot of poles.

As a terminal which meets such a demand, there is, for example, one in which an Au plating layer is formed on the surface of the terminal. A
By providing the u-plated layer on the surface, the insertion force of the terminal is reduced. However, since Au is very expensive, there is a problem in that the manufactured connector terminals are expensive. Therefore, it is applied only to a part of the connector terminals that require high reliability.

As a general connector terminal, Cu is used.
Such a conductive base material having Sn plating on its surface is used. In the case of this terminal, since Sn is an easily oxidizable material, a hard Sn oxide film is always formed on the surface in the atmosphere. Then, when this terminal is inserted, the above-mentioned hard Sn oxide film is broken at the time of fitting with the mating material. Then, the unoxidized Sn plating layer located therebelow and the mating material come into contact with each other, and good electrical connection is realized between them. However, when the formed Sn plating layer is thin, the entire plating layer forms an oxide film, which makes it difficult for the oxide film to break during fitting. Moreover, when the base material is made of Cu or a Cu alloy, when actually used in a high temperature environment, the Sn component of the thin Sn plating layer on the surface reacts with the base component to expose the Cu component to the surface, An oxide film of Cu is formed on. As a result, contact reliability with the mating material is lost.

Such a problem can be suppressed by increasing the thickness of the Sn plating layer on the surface. However, in that case, a new problem arises that the insertion force with the mating material becomes large at the time of fitting. Therefore, especially in the case of a connector terminal used in a high temperature environment, an expensive Au-plated terminal or Sn on the surface is used.
There is a problem that any one of Sn-plated terminals having a large thickness of the plating layer and having a small number of poles must be used.

By the way, when a plating layer made of Sn or a Sn alloy is formed on the surface of a terminal, in general, a gloss Sn is used.
Plating and reflow Sn plating are applied. Among these, in the case of a plating layer formed by bright Sn plating, the plating layer contains a large amount of additive components used during the plating process. Also, the crystal grains of the plating Sn become fine. Therefore, the lubricity of the plating layer surface is excellent,
In addition, the amount of abrasion during fitting / sliding is reduced. as a result,
Excellent mating / unmating properties when mated. However, since the crystal grains are fine, the number of grain boundaries is large, and when used in a high temperature environment, the base material component diffuses through the grain boundaries of the plating layer to the surface and contaminates the surface of the plating layer. Sometimes. Therefore, the material of the bright Sn plating is inferior in heat resistance and is likely to impair the connection reliability.

On the other hand, in the case of reflow Sn plating, the surface plating layer is heated and melted after the entire plating process is completed. Therefore, in the formed reflow plating layer, the crystal grain size is large, and the additive component mixed during the plating process is also removed. Therefore, the number of grain boundaries is small, and even in a high temperature environment, deterioration of connection reliability due to diffusion of base material components does not easily occur, and a plating material with improved heat resistance is obtained. However, since the crystal grain size of Sn on the surface is large, the amount of abrasion at the time of fitting / sliding becomes large, and since the additive component is also small, the lubricity is poor and the insertability thereof is deteriorated.

Under these circumstances, various methods have been proposed in order to enhance the heat resistance and insertability of the Sn plating layer. For example, JP-A-8-7940 and JP-A-4-3
Japanese Patent No. 29891 discloses S for the purpose of improving heat resistance.
A method of forming a plating layer of a refractory metal, especially Ni, as a base of the n plating layer is disclosed. According to this method, when the operating temperature range is about 100 to 120 ° C., the underlying Ni plating layer suppresses the reaction between the base material component (alloy component such as Cu and Zn) and the Sn component of the Sn plating layer. Then
Moreover, since the reaction rate between Ni and Sn is small, it is said that a heat resistance effect can be obtained. However, in a high temperature environment of 140 ° C. or higher, the reaction rate between Ni and Sn becomes large, the surface Sn plating layer is deteriorated, and the heat resistance effect cannot be obtained.

Further, Japanese Patent Laid-Open No. 11-121075 and Japanese Patent Laid-Open No. 10-302864 disclose a method of reducing the thickness of the Sn plating layer on the surface in order to improve the inserting / removing property. In the case of the surface Sn plating layer formed by this method, it is said that the amount of abrasion during fitting / sliding is reduced and the insertability is improved. However, since the Sn plating layer is thin, when used in a high temperature environment,
The Sn plating layer on the surface is deteriorated at an early stage due to diffusion of the base material component, and it becomes difficult to secure electrical connection reliability.

As described above, in the case of the conventional plating material having the Sn plating layer formed on the surface thereof, there is a problem that it is very difficult to achieve both heat resistance and insertability / extractability.

[0015]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Alternatively, in a plating material on which a Sn alloy plating layer is formed, the diffusion reaction between the plating layer and the base material or underlying plating layer is slowed even under a high temperature environment. To provide a plating material with good heat resistance, and also with good heat resistance as described above, as well as easy insertion / removal, that is suitable as a material for a mating connector or contactor used in a high temperature environment. To aim.

A further object of the present invention is to provide a method for producing the above-mentioned plating material, and an electric / electronic component using the plating material, such as a fitting type connector and a contact.

[0017]

In order to achieve the above-mentioned object, in the present invention, Fe is formed on the surface of the conductive substrate.
Or Fe alloy, Ni or Ni alloy, or Co
Alternatively, a base plating layer made of any one of Co alloys, and a first intermediate plating layer made of Sn or Sn alloys,
A second intermediate plating layer made of Cu or a Cu alloy, and Sn
Alternatively, there is provided a plating material characterized in that the surface plating layer made of Sn alloy is formed in this order.

Further, in the present invention, Fe or Fe alloy, Ni or Ni alloy,
Alternatively, a base plating layer made of any one of Co or Co alloy, a first intermediate plating layer made of Sn or Sn alloy, a second intermediate plating layer made of Cu or Cu alloy, and a surface made of Sn or Sn alloy. Provided is a method for producing a plating material, which comprises forming a plating layer and a plating layer in this order.

Further, the present invention provides an electric / electronic component excellent in heat resistance using the above-mentioned plating material, specifically, a fitting type connector or a contactor.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The plating material of the present invention has a five-layer structure as described later. The constituent materials and thicknesses of the respective layers are designed as described later in relation to the above-mentioned improvement in heat resistance and the simultaneous stabilization and improvement of heat resistance and insertability / extractability. First, the plating material of the present invention, as shown in FIG. 1, as a whole, on a conductive base material 1, a base plating layer 2, a first intermediate plating layer 3, a second intermediate plating layer 4, which will be described later, And the surface plating layer 5 is formed in this order. In this plating material, a first intermediate plating layer 3 and a second intermediate plating layer 4 are interposed between a base plating layer 2 and a surface plating layer 5, and these first intermediate plating layer 3 and second intermediate plating layer 4 will be described later. The most significant feature is that the disappearance of the surface plating layer 5 in a high temperature environment is suppressed by exhibiting the function of.

First, the material of the conductive base material 1 is not particularly limited, and may be appropriately selected according to the required mechanical strength, heat resistance, and conductivity, for example, in consideration of its use as a connector. Good. Commonly used materials include
For example, pure copper; phosphor bronze, brass, nickel silver, beryllium copper,
Copper alloy such as Corson alloy; pure iron, iron alloy such as stainless steel; various nickel alloys; Cu coated Fe material and N
It may be appropriately selected from composite materials such as i-coated Fe material.

Of these materials, Cu or Cu alloy is preferable. If the conductive base material 1 is not a Cu-based material, the surface of the conductive base material 1 may be plated with Cu or a Cu alloy before being used for practical use, so that the adhesion and corrosion resistance of the plated film are further improved. The base plating layer 2 formed on the conductive base material 1 is provided in order to secure the adhesion strength between the base material 1 and the surface plating layer 5, and the components of the base material are thermally diffused to the surface layer side. It also functions as a barrier layer that prevents this.

Specifically, the base plating layer 2 is formed of Fe or Fe alloy, Ni or Ni alloy, Co or Co alloy, or the like. All of these Fe, Ni and Co are high melting point metals having a melting point of 1000 ° C. or higher. And, for example, since the operating environment temperature of the connector is generally 200 ° C. or lower, it is a matter of course that the undercoat plating layer 2 is unlikely to cause thermal diffusion under such an operating environment. Effectively prevent heat diffusion to the.

The alloys containing them as main components include, for example, Ni-P, Ni-Sn, Co-P, and Ni-.
Co, Ni-Co-P, Ni-Cu, Ni-Cr, Ni
-Zn, Ni-Fe, etc. can be mentioned. Here, the thickness of the base plating layer 2 in the plating material is 0.0
It is preferably set within the range of 5 to 2 μm.

If the thickness of the base plating layer 2 is too thin, the above-mentioned effects cannot be sufficiently exhibited, and if it is too thick, the adhesion strength with the base material 1 becomes low and peeling from the base material 1 becomes easy. is there. Next, the first intermediate plating layer 3 formed on the base plating layer 2 is made of Sn or Sn alloy.

The first intermediate plating layer 3 is a second intermediate plating layer which will be described later when the plating material for which the plating up to the surface plating layer 5 is completed is subjected to high temperature treatment or is exposed to a high temperature environment. The component of the layer 4 (Cu component) reacts with the component of the base plating layer 2 (Ni, Fe, Co component, etc.) described above. And, Sn is formed between the second intermediate plating layer 4 and
A Cu-based metal compound is formed, and an Sn- (Ni, Fe, Co) -based metal compound is formed between the Cu-based metal compound and the underlying plating layer 2. Therefore, the thickness of the first intermediate plating layer 3 made of Sn or Sn alloy becomes smaller. Then, when all the Sn components of the first plating layer 3 are consumed and become Sn-Cu-based intermetallic compound or Sn- (Ni, Fe, Co) -based intermetallic compound, the first intermediate plating layer 3 is , As a whole, is converted into the first intermetallic compound layer 3 '.

This first intermetallic compound layer 3'is formed on the substrate 1
The thermal diffusion of the component of the above and the component of the base plating layer 2 to the surface plating layer 5 is delayed, and the surface plating layer 5 concerned is delayed.
Acts to prevent the deterioration of. However, on the other hand, it is brittle. The thickness of the first intermediate plating layer 3 that changes as described above under heat treatment or high temperature environment is 0.05 to 0.5 μ.
It is preferably set to m. If the thickness is too thin, the above-mentioned first intermetallic compound layer 3'is not sufficiently formed, which causes deterioration of the surface plating layer 5, and if it is too thick, the base plating layer 2 and the first plating layer 2 are not formed. This is because peeling easily occurs between the two intermediate plating layers 4.

Next, the second intermediate plating layer 4 formed on the first intermediate plating layer 3 is made of Cu or Cu alloy. When the second intermediate plating layer 4 is subjected to heat treatment or exposed to a high temperature environment, the Cu component of the second intermediate plating layer 4 and the first intermediate plating layer 4 become
A Cu—Sn based intermetallic compound is formed with the Sn component of the intermediate plating layer 3, and a Cu—Sn based intermetallic compound is also formed with the Sn component of the surface plating layer 5. As a result, the second intermediate plating layer 4 has the second intermediate plating layer 4 as shown in FIG.
Of the Sn-Cu intermetallic compound is converted into a layer 4 '.

Also in this second intermetallic compound layer 4 ', like the above-mentioned first intermetallic compound layer 3', the base material component and the component of the base plating layer are thermally diffused toward the surface plating layer 4. It functions as a barrier to prevent this. The thickness of the second intermediate plating layer 4 which changes as described above under heat treatment or high temperature environment is preferably set to 0.05 to 0.29 μm. If the thickness is made too thin, the second intermetallic compound layer 4'is not sufficiently formed, which causes alteration of the surface plating layer 5, and if it is made too thick, for example, a connector terminal is made from the manufactured plating material. This is because the plating material is likely to peel off at the second intermediate plating layer 4 during processing.

Although the first intermetallic compound layer 3'and the second intermetallic compound layer 4'described above are automatically formed in a high temperature environment, heat treatment during the production of the plating material, It is also possible to form the produced plating material by further subjecting it to reflow treatment. In that case, the plating material is stable in the initial state. For example, when it is formed in the manufacturing process of the plating material, batch heat treatment at 100 to 600 ° C. for several hours or more, running heat treatment at 180 to 230 ° C. for about several seconds (surface is not melted), actual temperature 230 to 300. ℃
Reflow treatment (melting and re-solidifying the surface) can be applied.

A layer 3'comprising the above-mentioned intermetallic compound,
When 4'is formed, the surface plating layer 4 of the outermost layer becomes
The thickness becomes thinner. Then, each of the first intermediate plating layer 3 and the second intermediate plating layer 4 has the first
When the conversion to the intermetallic compound layer 3'and the second intermetallic compound layer 4'is completed, the intermetallic reaction based on thermal diffusion ends. Therefore, as shown in FIG.
Alternatively, it is possible to leave a surface plating layer of a certain thickness without losing the surface plating layer 5 made of Sn alloy.

When the thicknesses of the base plating layer 2, the first intermediate plating layer 3 and the second intermediate plating layer 4 are set as described above, the thickness of the surface plating layer 5 during plating is set to 0.1 μm or more. If so, it is possible to prevent the plating material from disappearing even when the plating material is heated at high temperature or exposed to a high temperature environment. The plating material of the present invention sequentially forms a base plating layer, a first intermediate plating layer, a second intermediate plating layer, and a surface plating layer on the surface of a base material using a predetermined alloy plating bath for each plating layer. Can be manufactured. In that case,
Regarding the formation of the first intermediate plating layer and the surface plating layer, it is preferable to apply the following method because the manufacturing cost can be significantly reduced.

That is, first, an Sn plating layer is formed on the surface of the lower layer (the base plating layer in the case of the first intermediate plating layer, the second intermediate plating layer in the case of the surface plating layer), and Ag, Ag, A plating layer of one or more metals of Bi, Cu, In, Pb and Sn is formed. The Sn plating layer described above may be a Sn alloy plating layer. Then, the entire laminate is subjected to a reflow treatment or a heat treatment to cause selective thermal diffusion between the metal of the metal plating layer and Sn of the Sn layer (or Sn alloy plating layer), Both are alloyed. In this way, the first intermediate layer 3 and the surface plating layer 5 made of Sn alloy are formed. For example, in the case of reflow processing, the actual temperature 230 to 3
Reflow treatment is performed at 00 ° C. for 5 seconds or less, and in the case of heat treatment, the temperature may be 100 to 120 ° C. for several hours.
This is because at this temperature, thermal diffusion between other layers hardly occurs.

[0034]

[Examples] Examples 1 to 9 and Comparative Examples 1 to 5 Brass strips were sequentially subjected to electrolytic degreasing and pickling, and were then provided with a base plating layer, a first intermediate plating layer, a second intermediate plating layer, and a surface plating layer. By sequentially forming, various plating materials shown in Table 2 were manufactured. The plating conditions for forming each layer are as shown in Table 1.

[0035]

[Table 1]

Each produced plating material was heated to the temperature shown in Table 2, and the remaining thickness of the surface plating layer and the contact resistance at that time were measured according to the following specifications. Moreover, the dynamic friction coefficient at the initial stage was measured according to the following specifications. Remaining thickness: The plating material was left in an air bath at a temperature of 100 to 160 ° C. for 120 hours and then measured by a constant current melting method.

Contact resistance: 1 at a plating material temperature of 160 ° C.
Measured after heating for 20 hours. Dynamic friction coefficient: Load 294 using Bowden type friction tester
Measured under conditions of mN, sliding distance of 10 mm, sliding speed of 100 M / min, and number of sliding times of 1. The mating material used was a brass strip having a plate thickness of 0.25 mm, plated with 1 μm of reflow Sn, and then overhanged to 0.5 mmR. The following results are collectively shown in Table 2.

[0038]

[Table 2]

The following is clear from Table 2. Comparing the example and the comparative example, the example shows that the surface plating layer (Sn) remains and the coefficient of dynamic friction is small even if the environmental temperature becomes high. And
The thicker the surface plating layer formed is, the thicker the surface plating layer (Sn) remains after heating and the more heat resistant it is. On the other hand, however, the coefficient of dynamic friction is smaller in the embodiment in which the thickness of the surface plating layer is thinner. For this reason, the thinner surface plating layer is more advantageous in terms of insertability and removal.

[0040]

As is apparent from the above description, the plating material of the present invention has a first plating layer between the undercoating layer and the surface plating layer.
The intermediate plating layer and the second intermediate plating layer are interposed, and the thicknesses of the surface plating layer and these intermediate plating layers are designed so that Sn or Sn alloy of the surface plating layer remains even in a high temperature environment. ing.

Therefore, this plating material has good heat resistance, and also has good heat resistance and insertability / extractability. For example, a connector arranged in a high temperature environment such as an automobile engine room, or a fitting. It is useful as a material for various electrical and electronic parts such as mold connectors and contacts.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a plating material of the present invention.

FIG. 2 is a cross-sectional view showing a layer structure when the plating material of FIG. 1 is exposed to a high temperature environment.

[Explanation of symbols]

1 Conductive substrate 2 Undercoat layer 3 First intermediate plating layer 3'first intermetallic compound layer 4 Second intermediate plating layer 4'second intermetallic compound layer 5 Surface plating layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Suzuki             2-6-1, Marunouchi, Chiyoda-ku, Tokyo             Kawa Electric Industry Co., Ltd. (72) Inventor Morimasa Tanimoto             2-6-1, Marunouchi, Chiyoda-ku, Tokyo             Kawa Electric Industry Co., Ltd. F-term (reference) 4K024 AA03 AA04 AA07 AA09 AA14                       AA21 AB04 BA01 BA02 BA04                       BA09 BB10 DB02 GA16                 4K044 BA06 BA10 BB05 BC06 BC11                       CA18 CA61

Claims (9)

[Claims] 1. Fe or Fe on the surface of a conductive substrate
Alloy, Ni or Ni alloy, or Co or Co
A base plating layer made of any one of alloys, a first intermediate plating layer made of Sn or Sn alloy, and Cu or C
A plating material characterized in that a second intermediate plating layer made of a u alloy and a surface plating layer made of Sn or a Sn alloy are formed in this order. 2. The thickness of the base plating layer is 0.05 to 2
μm, and the thickness of the first intermediate plating layer is 0.05 to
The plating material according to claim 1, which has a thickness of 0.5 μm and a thickness of the second intermediate plating layer of 0.05 to 0.29 μm. 3. The plating material according to claim 1, wherein the surface plating layer is a layer that has been subjected to heat treatment or reflow treatment. 4. The Sn alloy of the first intermediate plating layer and the surface plating layer is Ag, Bi, Cu, In, Pb, Sb.
1. At least one selected from the group
Any of the plating materials of 3. 5. Fe or Fe on the surface of the conductive substrate
Alloy, Ni or Ni alloy, or Co or Co
A base plating layer made of any one of alloys, a first intermediate plating layer made of Sn or Sn alloy, and Cu or C
A method for producing a plating material, characterized in that a second intermediate plating layer made of a u alloy and a surface plating layer made of Sn or a Sn alloy are formed by plating in this order. 6. The thickness of the base plating layer is 0.05 to 2
μm, the thickness of the first intermediate plating layer is 0.05 to 0.5 μm
m, and the thickness of the second intermediate plating layer is 0.05 to 0.5.
The method for producing a plating material according to claim 5, wherein the plating material has a thickness of 29 μm. 7. The method for producing a plating material according to claim 5, wherein a reflow treatment is performed after forming the surface plating layer. 8. An electric / electronic component excellent in heat resistance, characterized by using the plating material according to any one of claims 1 to 4. 9. The electric / electronic component according to claim 8, wherein the electric / electronic component is a fitting type connector or a contact.