JP2951462B2 - Sealing treatment method for gold plated material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sealing gold or a gold alloy plating material provided with nickel or nickel-containing alloy plating of a copper-based metal material as a base, and a connector contact which has been sealed. Particularly, the present invention relates to a sealing solution, a sealing method, and a connector contact that has been subjected to a sealing process, which is excellent in corrosion resistance even if the thickness of gold or gold alloy plating is thin, and has stable and excellent electrical connectivity over a long period of time. .

[0002]

2. Description of the Related Art A connector is the most typical connector for electronic equipment, and various connectors have been put to practical use. Connectors used in so-called industrial electronic devices that require a high degree of reliability, such as computers and communication devices, are made of a copper alloy for springs such as phosphor bronze and beryllium copper and are plated with gold. It is commonly used. However, since gold is expensive, various methods have been employed to reduce connector manufacturing costs. A typical method is to reduce the thickness of the gold plating. However, there is a problem that the thickness of the gold plating is reduced, the number of pinholes in the coating film increases exponentially, and the corrosion resistance is significantly reduced. One of the methods for solving this problem is a sealing treatment. That is, the surface of the gold plating is treated with various inorganic or organic chemicals to close the pinholes and improve the corrosion resistance. There are aqueous and organic sealing methods. The water system is typically a chromate method, which is effective but may increase the contact resistance and has a problem of environmental pollution. In the case of an organic solvent, a problem of environmental pollution arises because a halogen-based organic solvent is generally used as a solvent. Although an aqueous system is more advantageous in reducing the environmental pollution of the solvent, no effective method of sealing gold or a gold-plated material other than the chromate method has been known.

[0003]

Therefore, there is a need for a sealing solution and a sealing method which have no problem in environmental pollution and have a sealing effect equal to or higher than the conventional one.

[0004] It is an object of the present invention to provide an improved sealing solution capable of satisfying such a demand and a sealing method using the same, and also provide a connector processed by the same. The purpose is to do so.

[0005]

In view of such circumstances, the present inventors have conducted intensive studies and as a result, have come to invent a sealing method and a connector contact which has been subjected to the following sealing treatment. That is, the present invention relates to (1) a method for sealing a gold or gold alloy plating material having a base metal coated with nickel or a nickel-containing alloy as a base, wherein the benzotriazole-based compound shown below is used as an inhibitor. 1 or 2 or more of 10 to 10
Electrolytic potential Ea (V, standard hydrogen electrode potential) in relation to the pH of the sealing solution is 0.5-0.0591 pH <Ea <1 with the plating material as an electrode in a sealing solution containing 00 ppm. DC electrolysis in the pH range of 0.0 to 0.0591 pH

[0006]

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And (2) a connector contact which has been sealed by the above sealing method.

According to the present invention, the electrode potential of a material to be treated is held in an oxidized area of nickel as a base plating and DC electrolysis is performed to oxidize the nickel as a base metal in a pinhole of gold plating, thereby forming nickel and benzo. This is a treatment method in which a triazole-based compound is reacted and a complex compound is filled in a pinhole to have a sealing effect.

The electrolytic potential Ea of the material to be treated is 0.5-0.0
As shown in the potential-pH diagram of nickel in an aqueous solution, nickel is easily passivated at a potential lower than 591 pH (V), and nickel-benzotriazole-based compounds are less likely to be formed at a potential lower than this, and pores are sealed. This is because the processing effect is significantly reduced. And, not limited to nickel, the passivation potential is affected by pH. On the other hand, when Ea is 1.
In the range of 0-0.0591 pH (V) or more, the generation of oxygen is remarkable, and the pH at the electrode interface is significantly lower than the pH of the solution, so that the corrosion and dissolution of nickel is promoted and the formation of a complex compound having a high sealing effect is prevented. .

[0010] The total amount of the inhibitor is 10 to 1000
The concentration of ppm is lower than 10 ppm because the sealing function is low. If the concentration is higher than 1000 ppm, the effect of the sealing treatment is saturated and the solubility of the inhibitor causes problems such as the promotion of dissolution of an inhibitor such as a surfactant or triethylamine. This is because an agent is required and is not useful at all.
However, even when the inhibitor concentration is 1000 ppm or less, there is no particular problem in adding them as a dissolution promoter.

The pH of the aqueous solution for pore treatment is preferably 7.0 or more. This is because at the time of the sealing treatment, the pH of the surface of the material to be treated becomes lower than the pH in the solution due to electrolysis and nickel is corroded and dissolved, but when the pH of the sealing treatment solution is lower than 7.0,
Elution of the oxidized nickel into the sealing solution is accelerated, and the nickel effect in the sealing solution increases with the decrease in the sealing effect, resulting in contamination of the sealing solution and deposition of nickel on the counter electrode. This causes a manufacturing obstacle. In a remarkable case, a corrosion product is found by the sealing treatment. pH
The adjustment is performed using a known buffer solution, and the buffer solution is not limited at all.

The inhibitor used in the present invention is:

[0013]

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## EQU1 ## For example, benzotriazole (R ₁ and R are both hydrogen), 1-methylbenzotriazole (R ₁ is hydrogen and R ₂ is methyl), 1- (N, N-dioctylaminomethyl) benzotriazole (R ₁ is hydrogen, R ₂ N, N-dioctyl amino methyl), tolyltriazole (R ₁ is methyl, R ₂ is hydrogen), sodium tolyltriazole (R ₁ is methyl, R ₂ is sodium) and the like are preferable.

In the present invention, in addition to the above-mentioned benzotriazole-based compounds, indazole-based compounds, benzimidazole-based compounds, indole-based compounds, 1,3,5-triazinethiol-based compounds and the like, which are known to have a corrosion inhibiting effect on nickel. It is effective to appropriately add an inhibitor to the sealing solution, and this is not prevented.

In addition, various surfactants for increasing wettability, alkylene glycols for increasing lubricity, and the like may be appropriately added to the sealing liquid.

In the case where the sealing treatment is performed after plating at the stage of a material such as a wire, a plate, and a strip, the plated product may be subjected to press working and then subjected to the sealing treatment with the sealing treatment solution and the sealing treatment method of the present invention. It is valid. Even in the case of a metal material that has been subjected to a sealing treatment after plating, the effect of the sealing treatment may be reduced in a step of cleaning press oil adhered in a subsequent press working. Therefore, the re-sealing process is effective. After the press working, plating and sealing can be performed.

In the subsequent connector processing step,
If there is a step of washing the plated product until the final assembly of the electronic device, the sealing effect is similarly reduced, so that it is effective to appropriately perform the sealing process according to the present invention. Therefore, the present invention also includes a connector processed by the sealing method of the present invention.

In the present invention, the metal material used as the plating base material is required characteristics of connectors such as various copper alloys such as copper, brass, phosphor bronze, titanium copper, beryllium copper, iron, stainless steel, and high nickel alloy. Can be appropriately selected in accordance with the above, and is not limited at all. A known plating method such as electroplating, electroless plating, or dry plating such as CVD or PVD can be applied to the plating method, and is not limited.

Further, a known method can be applied to the plating conditions. The gold alloy plating is an alloy plating based on gold, and is appropriately selected depending on the application. Hard plating containing a small amount of cobalt is widely used in connectors for improving wear resistance. The base plating is generally made of nickel alone or a palladium alloyed with nickel of 10 to 20%, but the present invention is effective if the alloy contains nickel.

[0021]

The present invention will be described in more detail with reference to the following examples.

Male and female continuous terminals were press-formed from cold-rolled phosphor bronze (C5210-H) having a thickness of 0.2 mm. These were electroplated through a continuous reel-to-reel electroplating line. In the plating line, after degreasing and pickling, nickel plating of 1 μm was performed in a Watt bath, and gold was partially plated on the contact portion with a thickness of 0.1 μm. In the continuous plating line, a sealing process was provided after gold plating, and the sealing process was performed by passing a continuous terminal.
The pH of the sealing solution was adjusted using a buffer solution. After the surface-treated male and female terminals were cut from the carrier portion and lead wires were crimped, they were fitted and subjected to an evaluation test.

Further, gold-cobalt alloy plating was applied to the gold plating, and phosphor bronze was applied to the phosphor bronze for the Pd 80% -Ni 20% alloy plating from an ammonia-based plating solution.

Contact resistance: DC 10 mmA, open voltage 50
It was measured in mmV. The corrosion test was performed under the following conditions.

Gas composition: H ₂ S 3 ppm SO ₂ 10 ppm Temperature: 40 ± 2 ° C. Humidity: 80 ± 5% RH Time: 96 hours The results are shown in Table 1.

[0026]

[Table 1]

Note 1) However, the abbreviations of the sealing liquid in the table are as follows.

A-1: benzotriazole A-2: 1-methylbenzotriazole A-3: tolyltriazole A-4: sodium tolyltriazole A-5: 1- (N, N-dioctylaminomethyl) benzotriazole ( R ₁ is hydrogen, R ₂ is N, N-dioctyl amino methyl) Note 2) criteria of the test are as follows.

(1) Initial contact resistance, contact resistance after corrosion test (average value of n = 5) ○: 10 mmΩ or less △: 10 to 20 mmΩ ×: 20 mmΩ or more (2) Appearance after corrosion test ○: Corrosion product None △: Corrosion products scattered ×: Corrosion spots are observed on the entire surface

[0030]

As described above, the contacts of the gold-plated material sealed according to the present invention have low contact resistance after the sealing treatment and exhibit excellent corrosion resistance even in a severe corrosive environment.
There is an advantage that the contact resistance does not increase and the contact performance is stable.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C25D 5/48 C25D 7/00

Claims (3)

(57) [Claims] 1. A method for sealing a gold or gold alloy plating material comprising a base metal coated with nickel or a nickel-containing alloy as a base material, wherein one of the following benzotriazole-based compounds or Electrolytic potential Ea (V, standard hydrogen electrode potential) was measured using the plating material as an electrode in an aqueous solution for sealing treatment containing a total of 10 to 1000 ppm of two or more kinds.
DC electrolysis in the range of 0.5-0.0591 pH <Ea <1.0-0.0591 pH in relation to the above method. Embedded image 2. The method according to claim 1, wherein the pH of the sealing solution is 7.0 or more. 3. A connector contact which has been sealed by the method according to claim 1.