JPH05311485A - Hole sealing treatment of noble metal plate material - Google Patents

Abstract

PURPOSE:To allow an eluted metal in the inside of pinholes to react with an organic component to seal by using a noble metal plating material as an anode and electrolyzing by PR method, A.C. method or the like in an aq. solution containing an organic compound having corrosion preventing effect on a base metal or the like. CONSTITUTION:The organic compound (e.g. nitrogen contained cyclic compound, imino acid derivative ethylenediamine or the like) having corrosion preventing effect on the base metal (e.g. copper (alloy), iron, stainless steel or the like) is prepared. Next, a plated material plating the noble metal (gold, silver, rhodium, palladium, ruthenium and these alloy) on the base metal is dipped into the solution containing the organic compound. And electrolysis is executed by the use of the plated material as the anode by PR method, A.C. method, A.C./D.C superimposed method or method using A.C. jointly while irradiating with ultrasonic wave. As a result, a rigid coated film is formed to seal by allowing the base metal eluted from the inside of the plating pinholes to react with the organic component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing treatment liquid for noble metal plated electrical contacts, a sealing treatment method, and a sealed connector contact. In particular, the present invention relates to a sealing treatment liquid, a sealing treatment method, and a connector contact having a sealing treatment, which are excellent in lubricity, rust prevention, and electrical connectivity and are stable for a long period of time.

[0002]

2. Description of the Related Art A connector is the most typical one as a connecting part for electronic equipment, and various types of connectors have been put to practical use. Connectors used for so-called industrial electronic devices that require a high degree of reliability, such as computers and electronic credit devices,
Base material is a spring copper alloy such as phosphor bronze or beryllium copper,
Those plated with noble metal are generally used. However, since precious metals are expensive, various methods have been adopted in order to reduce the manufacturing cost of connectors. A typical method therefor is to reduce the thickness of the noble metal plating. However, there is a problem that the thickness of the noble metal plating is reduced and the number of pinholes in the coating increases exponentially, resulting in a significant decrease in corrosion resistance. One of the methods for solving this problem is a sealing treatment. That is, the precious metal plating surface is treated with various inorganic or organic chemicals to block the pinholes,
It is intended to improve the corrosion resistance. There are water-based and organic-based sealing treatments. The chromate method is typically used for the water system, and although it is effective, the contact resistance may increase and there is a problem of environmental pollution. As the organic type, a halogen type organic solvent is generally used, but there is a problem of environmental pollution. Water is more advantageous in terms of environmental pollution,
The effect is low except for the chromate method.

[0003]

The sealing treatment, particularly the sealing treatment with an organic chemical, has an excellent effect of maintaining the corrosion resistance against the reduction of the thickness of the noble metal plating film. But,
As described above, since the organic sealing treatment liquid is generally a halogen-based organic solvent, it has a problem in environmental pollution.
In terms of environmental pollution, an aqueous system in which the solvent is water is more advantageous than an organic system, but other than the chromate method, the effect is low and the sealing effect is insufficient. Therefore, there is a need for a sealing treatment liquid and a sealing treatment method which have no problem of environmental pollution and have a sealing effect equal to or higher than conventional ones.

An object of the present invention is to provide an improved sealing treatment liquid and a sealing treatment method using the same which can meet such requirements, and also to provide a connector treated therewith. The purpose is that.

[0005]

In view of the above situation, the inventors of the present invention have made earnest studies and, as a result, have invented a sealing treatment method, and a plated material and a connector subjected to the sealing treatment described below. That is, the present invention provides (1) gold, silver, rhodium, palladium, ruthenium, or an alloy plating material thereof, as a base metal or a base metal component thereof, or 2
Sealing treatment of a noble metal plating material, characterized in that the plating material is electrolyzed by a PR method, an alternating current method, an alternating direct superposition method, or an alternating current combined method in an aqueous solution containing an organic compound having a corrosion inhibiting effect for more than one species. A method, (2) a plated material that has been subjected to a sealing treatment by the sealing treatment method, and (3) a contact that has been subjected to a sealing treatment by the treatment method.

The base metal in the present invention includes a base metal of noble metal plating and a raw material metal. The present invention elutes the base metal of the material to be treated inside the noble metal plated pinhole by subjecting the material to be treated as an anode to direct current electrolysis, and the base metal and the eluted metal react with the organic component to form a strong coating. This is a treatment method that has a sealing treatment. The pH of the sealing treatment aqueous solution is preferably higher than 7.0. This is because during the sealing treatment, the pH of the surface of the material to be treated becomes lower than the pH in the liquid due to electrolysis.
Is too low, the amount of base metal eluted is large, and the coordinating force of the organic component is weakened, which is not preferable.
The pH adjustment is performed using a known buffer solution, and the buffer solution is not limited at all.

The AC / DC superposition method is an energization method in which AC and DC are simultaneously used, and the AC combined method is a method in which AC and DC are used individually and alternately. In direct current electrolysis, a difference is likely to occur in the current density on the surface of the material to be treated, the sealing treatment coating becomes non-uniform, which is not preferable, and this tendency becomes stronger as the shape of the material to be treated becomes complicated. In the sealing treatment method of the present invention, the electrolytic treatment is carried out by the electrolytic method such as the PR method, the alternating current method, the alternating direct superposition method or the alternating current combined method, so that the difference in the current density on the surface of the material to be treated hardly occurs and the sealing treatment The coating becomes almost uniform.

When the material to be treated is electrolytically treated by immersing it in the sealing treatment solution of the present invention, if the sealing treatment solution of the present invention does not penetrate into the pinholes of the noble metal plating, the underlying metal and the sealing hole of the present invention are used. Since the treatment liquid does not come into contact with the treatment liquid, a complex compound is not formed, and thus a sufficient sealing treatment effect cannot be obtained. Therefore, the cavitation effect can be obtained by performing the sealing treatment while irradiating ultrasonic waves, and the sealing treatment liquid of the present invention penetrates into the pinholes of the noble metal plating, and the base metal and the sealing treatment liquid of the present invention contact each other. It becomes possible to generate a complex compound. The installation position of the ultrasonic transducer may be on the floor surface or the side surface in the processing tank, and is not limited in any way.

The treatment temperature of the pore-sealing treatment is not limited in any way, but it is desirable to set the temperature to about 60 to 80 ° C. because the higher temperature allows easier drying.

The following organic compounds are preferable as the organic compound having a corrosion inhibiting effect used in the present invention.

That is, it has a nitrogen-containing cyclic compound, an imino acid derivative, ethylenediamine, ethylenediaminetetraacetic acid, gluconic acid, nitrotriacetic acid, hydroxyethyl, ethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, a carbon number of 6 to 30, and α One or two of monocarboxylic acid having OH group at the position and its derivative, metal salt of higher fatty acid having 6 to 30 carbon atoms, alkyl-substituted naphthalene sulfonate, amine having 6 to 30 carbon atoms
It is more than a seed.

As the nitrogen-containing cyclic compound,

[0013]

[Chemical 1]

(In the above formulas, R ₁ represents hydrogen, alkyl or substituted alkyl, and R ₂ represents alkali metal, hydrogen, alkyl or substituted alkali) and the like.

The benzotriazole type compounds include benzotriazole (both R ₁ and R ₂ are hydrogen), 1-methylbenzotriazole (R ₁ is hydrogen, R ₂ is methyl), 1- (N,
N-dioctylaminomethyl) benzotriazole (R
₁ is hydrogen, R ₂ is N, N-dioctylaminomethyl), tolyltriazole (R ₁ is methyl, R ₂ is hydrogen), sodium tolyltriazole (R ₁ is methyl, R ₂ is sodium) and the like are preferable.

Examples of the indazole system include indazole (both R ₁ and R ₂ are hydrogen), 2-methylindazole (R ₁ is hydrogen, R ₂ is methyl), 2-benzylindazole (R ₁ is hydrogen, R ₂ is C). ₆ H ₅ CH ₂ ), 1-acetylindazole (R ₁ is hydrogen, R ₂ is COCH ₃ ) and the like are preferable.

Examples of the benzimidazole type compounds include benzimidazole (both R ₁ and R ₂ are hydrogen), N-acetylbenzimidazole (R ₁ is hydrogen, R ₂ is COC).
H _3), N-benzoyl benzimidazole (R ₁ is hydrogen, R ₂ is COC ₆ H ₅₎ are preferred.

Examples of the indole system include indole (both R ₁ and R ₂ are hydrogen), indole-1-carboxylic acid (R ₁ is hydrogen, R ₂ is COOH), 1-methylindole (R ₁ is hydrogen, R ₂ Is preferably CH ₃ ).

As the 1,3,5-triazine compound, for example, 6-substituted-1,3,5-triazinethiol-sodium salt

[0020]

[Chemical 2]

(R is --SH, or an amino group substituted with an alkyl group or an aryl group, for example --NHC.
_{H 3, -NHC 2 H 5,} -N (CH 3) 2, -N (C
_{2 H 5) 2, -NHC 6} H 5, -N (C 4 H 9) 2, -N (C 8
_{H 17) 2, -N (C} 12 H 24) 2, -N (CH 2 CH = C
H _{2) 2,} etc. _{-NHC 8 H 16 CH = CHC 8} H 17 are preferable. ) Cyanuric acid (2,4,6-trioxy-1,3,3
5-triazine),

[0022]

[Chemical 3]

Melamine compound (2-substituted-4,6 diamino-1,3,5-triazine)

[0024]

[Chemical 4]

{R is --NH ₂ ,

[0026]

[Chemical 5]

(R 'is an alkyl group such as CH ₃ , C ₂ H ₅ , C ₁₁ H ₂₃ )}.

Examples of the imino acid derivative include imino diacetonitrile {NH- (CH ₂ CN) ₂ }, imino dicarboxylic acid {NH- (COOH) ₂ } and imino diacetic acid {NH-.
(CH ₂ COOH) ₂ } and the like are preferable.

Further, ethylenediamine, ethylenediaminetetraacetic acid (EDTA), gluconic acid, nitrotriacetic acid (N
TA), hydroxyethyl ethylenediamine triacetic acid (H
EDTA), diethylenetriaminepentaacetic acid (DTPA)
Etc. are also effective as a component of the sealing treatment liquid used in the present invention.

The general formula of the monocarboxylic acid having 6 to 30 carbon atoms and having OH at the α-position, which is effective as a component of the sealing treatment liquid of the present invention, is as follows:

[0031]

[Chemical 6]

It is shown by. Examples thereof include maleic acid, oleic acid, naphthenic acid and the like. Examples of the monocarboxylic acid derivative having C _{6 to} C ₃₀ and OH in the α-position include maleic oil of nuka oil and sodium naphthenate.

Examples of the metal salt of higher fatty acid having 6 to 30 carbon atoms include metal stearate, metal laurate, metal ricinolenate, metal myristicate, metal oleate, metal naphthenate and naphthene. Examples thereof include acid metal salts, and the metal salts are not particularly limited, but calcium, aluminum, barium, lead salts and the like are preferable.

Alkyl-substituted naphthalene sulfonates include barium dinolyl naphthalene sulfonates,
Calcium salt of dinolylnaphthalene sulfonic acid, zinc salt of dinolyl naphthalene sulfonic acid, basic salt of dinolyl naphthalene sulfonic acid barium salt, dinolyl naphthalene sulfonic acid ethylenediamine salt, dinolyl naphthalene sulfonic acid sodium salt, dinolyl naphthalene sulfonic acid lithium salt, Dinolyl naphthalene sulfonic acid lead salt,
Examples thereof include ammonium dinolylnaphthalene sulfonic acid, triethanolamine dinolyl naphthalene sulfonic acid, and the like.

As the amine having 6 to 30 carbon atoms,
Octadecylamine, dodecylamine, decylamine,
Examples thereof include octylamine and cyclohexylamine.

The addition of a surfactant as a component of the sealing treatment liquid of the present invention is effective in improving the wettability between the sealing treatment liquid of the present invention and the material to be treated, and is not limited in any way. Further, addition of a lubricant as a component of the sealing treatment liquid of the present invention is effective in reducing the friction of the sealing treatment material of the present invention and is not limited in any way.

It is also effective to perform a sealing treatment on the plated product after pressing with the sealing treatment liquid and the sealing treatment method of the present invention. Even with a metal material that has been subjected to a pore-sealing treatment after plating, the effect of the pore-sealing treatment decreases in the step of washing the press oil that has adhered in the subsequent press working. Therefore, the sealing treatment again becomes effective.

Also in the subsequent connector processing steps,
If there is a step of washing the plated product until the final electronic device is assembled, the effect of the sealing treatment is similarly reduced. Therefore, it is effective to appropriately perform the sealing treatment according to the present invention. Furthermore, when the sealing treatment effect decreases with the amount used after being incorporated in an electronic device, it can be appropriately treated by the method of the present invention. Therefore, the present invention also includes a connector processed by the sealing method of the present invention.

The metal material used as the plating base material in the present invention is copper, brass, phosphor bronze, titanium copper, beryllium copper, or other various copper alloys, iron, stainless steel, high nickel alloys, or other plating materials such as connectors. Can be appropriately selected according to the required characteristics of, and is not limited in any way. Also, regarding the base plating,
Nickel, nickel-cobalt, palladium-nickel, tin-nickel, silver and the like are used, and nickel is particularly preferable. The plating material can be plated by electroplating, electroless plating, or dry plating such as CVD or PVD. Known ones can be applied and are not limited.

[0040]

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

Male and female continuous terminals were each press-molded using a 0.2 mm-thick cold-rolled material of spring phosphor bronze (C5210-H). These were electroplated through a reel-to-reel continuous electroplating line. In the plating line, after degreasing and pickling, 1 μm nickel plating was performed in a Watts bath, and gold was partially plated on the contact portion with a thickness of 0.1 μm. Further, in the continuous plating line, a sealing treatment step was provided after gold plating, and the continuous terminal was inserted to perform the sealing treatment at 70 ° C. The pH of the sealing treatment liquid was adjusted using a buffer solution.

After the surface-treated male and female terminals were cut from the carrier and the lead wires were crimped, the terminals were fitted and subjected to an evaluation test.

Contact resistance is DC 10 mmA, open voltage 50
It was measured in mmV. The corrosion conditions were as follows.

Gas composition: H ₂ S 3 ppm SO ₂ 10 ppm Temperature: 40 ± 2 ° C. Humidity: 80 ± 5% RH time: 240 hours The results are shown in Tables 1 to 4.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

[Table 4]

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

A-1: benzotriazole A-2: 1-methylbenzotriazole A-3: tolyltriazole A-4: indazole A-5: benzimidazole A-6: indole A-7: 1,3,5- Triazine-2,4,6-trithiol monosodium A-8: 6-Dimethylamino-1,3,5-triazine-2,4-dithiol monosodium A-9: Cyanuric acid A-10: Melamine A-11 : Iminodiacetonitrile A-12: iminodicarboxylic acid A-13: iminodiacetic acid A-14: ethylenediamine A-15: ethylenediaminetetraacetic acid A-16: nitrotriacetic acid A-17: hydroxyethyl, ethylenediaminetriacetate A-18: Diethylenetriamine pentaacetic acid B-1: Maleic acid B-2: Oleic acid B-3: Na Tenic acid B-4: Barium stearate B-5: Barium laurate B-6: Calcium oleate B-7: Calcium naphthenate B-8: Barium dinolylnaphthalene sulfonate B-9: Lithium dinolynaphthalene sulfonate B-10: Triethanolamine dinolylnaphthalene sulfonic acid B-11: Octadecylamine B-12: Dodecylamine B-13: Decylamine Note 2) The criteria for the test are as follows.

Initial contact resistance, contact resistance after corrosion test (average value of n = 5) A: 10 mmΩ or less B: 10 to 20 mmΩ C: 20 to 50 mmΩ D: 50 to 100 mmΩ E: 100 mmΩ or more Appearance after corrosion test A : No corrosion products B: Corrosion products scattered C: Corrosion points are observed on the entire surface

[0052]

As described above, the noble metal plating material which has been subjected to the sealing treatment according to the present invention has a low contact resistance immediately after the sealing treatment and exhibits excellent corrosion resistance even in a severe corrosive environment.
It has advantages that the contact resistance does not increase and the contact performance is stable.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C25D 5/18 5/20

Claims (4)

[Claims] 1. An aqueous solution containing gold, silver, rhodium, palladium, ruthenium, or an alloy plating material of these, containing an organic compound having a corrosion-inhibiting effect on the underlying metal or one or more of the underlying metal components. A method for sealing a noble metal plated material, which comprises electrolyzing the plated material with an anode by a PR method, an alternating current method, an alternating direct superposition method, or an alternating current combined method. 2. The sealing treatment method according to claim 1, wherein the sealing treatment is performed while irradiating ultrasonic waves. 3. A plated material which has been subjected to a sealing treatment by the sealing treatment method according to claim 1. 4. A connector contact that has been subjected to a sealing treatment by the sealing treatment method according to claim 1.