JPH051367A - Copper alloy material for electric and electronic equipment - Google Patents

Abstract

PURPOSE:To obtain a copper alloy for electric and electronic equipment excellent in formability, corrosion resistance, heat resistance and contact resistance by applying Ni plating on the surface of a copper alloy, thereafter diffusing Ni into the copper alloy by heat treatment or furthermore plating its surface with Au, Sn or the like. CONSTITUTION:The surface of a contact and terminal material made of various copper alloys is plated with Ni at 0.01 to 0.5mum thickness. After that, it is subjected to heat treatment in an atmosphere of a reducing gas mixed with a nitrogen gas and a hydrogen gas, e.g., at 450 deg.C for 1hr to diffuse the Ni plated layer into the copper alloy and to alloy the Ni. By the alloying of the Ni-plated layer, cracking and peeling are not generated at the time of forming such as press working, so that excellent workability can be obtd. Moreover, at the time of plating the surface of the Cu alloy finished with the Ni plating diffusing treatment with Au, Sn, solder or the like, by the presence of the Ni plating diffusing layer, the atomic diffusion of the plated layer such as Au into the Cu allay can be prevented, the secular degradation of the Au plated layer or the like can be prevented and its contact resistance value can always be held to low one.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy material for electric / electronic equipment used as a contact / terminal material for various electric / electronic equipment parts.

[0002]

2. Description of the Related Art Currently, contacts for various electric and electronic equipment parts
In addition to the strength and spring properties of the material, the terminal material is required to have corrosion resistance, heat resistance, solderability, low contact resistance, molding workability, etc. as reliability in the contact area. Various copper alloy materials suitable for the environment are used.

On the other hand, with the recent miniaturization and high-density mounting of electric / electronic equipment parts, a copper alloy material excellent in electrical conductivity and mountability has been demanded, and the copper alloy material alone is sufficient for this request. In fields that cannot meet these requirements, various plated copper alloy materials are used.

In other words, in the field of industrial connectors and the like where there is a strong demand for high reliability of contacts, gold-plated copper alloy materials, which are excellent in low stability of contact resistance, are the mainstream. Further, in fields where there is a strong demand for cost reduction of consumer connectors and the like, inexpensive copper alloy materials coated with tin or tin alloy (solder) are generally used instead of expensive gold plating. Further, a Ni alloy-plated copper alloy material has been put into practical use for the purpose of improving decorativeness, corrosion resistance, and heat resistance reliability.

[0005]

However, since the conventional copper alloy materials have the following problems, the requirements for higher reliability and cost reduction of electric / electronic devices cannot be satisfied. It was

(1) Copper alloy materials alone, except for copper alloys containing a large amount of Ni such as nickel silver and cupronickel, generally have poor corrosion resistance and heat reliability, including brass, and cause poor contact. .

(2) Since the Ni plating layer applied for the purpose of improving the corrosion resistance and the heat resistance reliability is hard and lacks in malleability, when the forming processing such as pressing is performed after plating, the bending portion is cracked. And the plating layer is likely to be lost. Plating may be applied after molding, but management becomes complicated,
It is more expensive than pre-plating.

(3) In the case of a copper alloy material plated with tin and tin alloy (solder), the intermetallic compound is formed by the tin in the plating and the copper in the copper alloy base material. This intermetallic compound becomes brittle over time. Further, this embrittlement is further promoted when heat is applied to the material continuously or intermittently, which causes the plating layer to peel from the base material. Further, in an alloy system containing a large amount of Zn such as brass, Zn passes through the plating layer and is deposited as an oxide on the surface with the lapse of time, so that the solderability is significantly deteriorated.

(4) In the case of a copper alloy material plated with gold, gold diffuses over time into the surface of copper in the copper alloy base material and is taken into the base material, so that the contact resistance increases. It may cause poor contact. On the other hand, Ni is widely used as the undercoat for the purpose of preventing such a diffusion phenomenon, but for the same reason as in (2), the formability after plating deteriorates.

The present invention has been made in order to solve the above-mentioned problems, and has better corrosion resistance and heat resistance than a single copper alloy material, and also has good moldability and is inexpensive electrical and electronic equipment. The purpose of the present invention is to obtain a copper alloy material for electric use, and also to obtain a copper alloy material for electric / electronic equipment capable of preventing deterioration of various platings over time and maintaining a low contact resistance.

[0011]

(1) In the copper alloy material for electric / electronic equipment according to the present invention, after Ni plating is applied to the surface of the copper alloy to a thickness of 0.01 to 0.5 μm, This is a product that is diffused in the base material by heat treatment (hereinafter,
The first copper alloy material). The reason for limiting the thickness of the Ni plating to the above range is that if it is less than 0.01 μm, it is too thin and the effect of Ni cannot be sufficiently obtained. If it exceeds 0.5 μm, the cost is high. This is because it lacks practicality.

(2) In the copper alloy material for electric / electronic equipment according to the present invention, the above copper alloy material having Ni diffused is plated with any one of gold, tin, and tin alloy (solder). (Hereinafter referred to as the second copper alloy material).

[0013]

(1) Ni is known as a metal that improves the corrosion resistance and heat resistance of copper alloys. The effect of this improvement is that even if a single layer such as plating is not formed, the concentration in the copper alloy is If it is contained above, it can be obtained. In the first copper alloy material, since Ni is diffused and alloyed on the surface of the copper alloy, the above-mentioned improvement effect can be expected. Further, in the Ni single layer, the formability is poor, but in the first copper alloy material, since Ni is diffused in the base material and alloyed, the formability is improved. Furthermore, conventional Ni
Compared with plated copper alloys, thin plating is easier to process, and complicated plating after molding can be omitted, resulting in low cost.

(2) Ni has an effect of suppressing atomic diffusion between Cu or Zn in the copper alloy base material and the gold or tin of the plating component, prevents deterioration of the plating over time, and improves contact resistance. It has the effect of holding it at a low level. This effect can be obtained even if a single layer is not formed unlike plating, as long as the copper alloy contains Ni at a certain concentration or higher. In the second copper alloy material, since Ni is diffused and alloyed on the surface of the copper alloy, the above effect can be expected.

[0015]

Example Using the representative copper alloys of phosphor bronze and brass as the base material, the copper alloy materials of Examples 1 to 16 and Comparative Examples 17 to 28 shown in Table 2 were prepared in the process of Table 1.

[0016]

[Table 1] The following test was performed about the copper alloy produced by the above process. (1) Heat-resistant adhesion test: [Test conditions] Test temperature: 1
00 ° C. Heat resistance time: 500, 1000 Hr Adhesion test: 180 ° adhesion Bending heat resistance Adhesion was evaluated by performing N = 20 and by the number of occurrences of peeling.

(2) Molding workability test: [Test conditions] Evaluation method: 90 ° V bending 0.2 ^R Molding workability was evaluated with and without cracks in the appearance of the bent portion.

(3) Contact resistance test: [Test conditions]
Test temperature: 85 ° C. Test humidity: 85% RH Test time: 350 Hr Measuring load: 50 gf Contact resistance was measured by N = 5 and evaluated by an average value.

(4) Corrosion resistance (ammonia stress corrosion resistance) test: [Test conditions] Atmosphere: 12.5% Ammonia reagent maximum bending stress: Tensile strength x 0.8 hours: 20Hr Corrosion resistance is the tensile strength before and after the test. The ratio was evaluated.

Table 2 summarizes the above test results. Each test result can be evaluated as follows.

[0021]

[Table 2] (1) Heat resistance adhesion: In the copper alloy materials of Examples 1 to 16,
In both cases, no peeling occurred in the surface layer of the base material or the boundary layer between the base material and the plating even after heat resistance of 1000 hours. On the other hand, in the tin and tin alloy (solder) plated materials of Comparative Examples 20, 21, 23 and 24, 1000 Hr
The peeling is markedly observed. This is due to the embrittlement of the plating interface accompanying the formation and growth of the intermetallic compound due to Sn during Cu plating in the copper alloy base material. Even if the copper alloy materials of Examples 6, 7, 8, 9, and 10 were the same tin and tin alloy (solder) plated materials, peeling did not occur. This is considered to be due to the diffusion suppressing effect of Ni.

(2) Formability: As can be seen from the copper alloy materials of Comparative Examples 25 and 26, the conventional Ni-plated ones have poor formability, while those of Examples 1 and 2 are poor. In the copper alloy material, since Ni is diffused in the copper alloy base material, cracks are not generated and the moldability is good. It should be noted that cracks are not observed in the copper alloys of Comparative Examples 27 and 28 alone, but cracks are observed in the Ni plated materials of Comparative Examples 25 and 26. This is considered to be due to the poor formability of Ni plating.

(3) Contact resistance: When the base material and plating (2) conditions are the same, for example, when comparing the copper alloy materials of Examples 5 and 8 and Comparative Example 19, the Example is the comparative example. The contact resistance is lower than that. In addition, Examples 1, 2,
Since the copper alloy materials 3 and 4 have been subjected to the diffusion treatment of Ni into the copper alloy material, the contact resistance is remarkably improved and the Ni plating is applied when compared with the copper alloy material alone of Comparative Examples 27 and 28. You can see that it is close to what you did. This is nothing but the fact that Ni, which is originally rich in corrosion resistance, shows its effect even when it diffuses into the base material instead of a single layer like plating. In addition, as seen in Comparative Examples 17 and 18, if the Ni plating thickness is too thin, the effect is not exhibited. When a copper alloy material is plated, N
It can be seen that i suppresses the diffusion phenomenon between the base material components of Cu and Zn and the plating components of gold and tin and keeps the contact resistance low.

(4) Stress corrosion resistance: As in (3), as can be seen from the comparison between Examples 1, 2, 3, 4 and Comparative Examples 17, 18, 27, 28, Ni base diffusion treatment was applied to the base material. It can be seen that the copper alloy material subjected to is significantly improved in corrosion resistance as compared with the copper alloy material alone.

In the above embodiment, after the final rolling, the Ni
Although the plating and diffusion treatments are performed, the same effect can be obtained even if these treatments are performed before the final rolling in the copper alloy manufacturing process.

In the heat treatment for the purpose of diffusion treatment, the same diffusion effect can be obtained under conditions other than the above-mentioned conditions, for example, heat treatment at high temperature for a short time and at low temperature for a long time. Other reducing atmosphere such as butane incomplete annealing gas may be used. Furthermore, after the heat treatment, pickling and chemical polishing treatment to the extent that the Ni diffusion layer on the surface is not damaged,
Useful for retaining surface activity.

[0027]

As described above, according to the invention described in claim 1, since the surface of the copper alloy is plated with Ni, it is diffused in the base material by heat treatment.
It is possible to obtain an inexpensive copper alloy material for electric / electronic devices, which is significantly richer in corrosion resistance and heat resistance than a copper alloy alone, and has good formability, and according to the invention of claim 2, The copper alloy material according to item 1 is plated with gold, tin, or a tin alloy (solder), so that deterioration of the plating over time is prevented, and therefore, the electrical resistance is excellent in low stability of contact resistance. -A copper alloy material for electronic devices can be obtained.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 25, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009] (4) When the copper alloy material subjected to gold plating, gold, over time, copper of the copper alloy base material is diffused into the front <br/> surface, since incorporated therein preform However, the contact resistance increases, which causes poor contact. On the other hand, Ni is widely used as the undercoat for the purpose of preventing such a diffusion phenomenon, but for the same reason as in (2), the formability after plating deteriorates.

Claims (2)

[Claims] 1. The surface of a copper alloy is plated with Ni to 0.01
A copper alloy material for electric / electronic devices, which is applied to a thickness of 0.5 μm and then diffused in a base material by heat treatment. 2. A copper alloy material for electric / electronic devices, which is obtained by plating the copper alloy material for electric / electronic devices according to claim 1 with gold, tin, or tin alloy (solder).