JPH07258891A - Method for sealing pinhole on gold-plated material - Google Patents

Abstract

PURPOSE:To completely seal the pinhole in the gold plating layer by forming a gold plating layer on the surface of a substrate metal of a connector with a Ni-base substrate plating layer in between, then electrolyzing the gold plating layer as an anode in a processing soln. of specified composition having a base oil-contg. layer on the surface and then pulling up the electrolysis product. CONSTITUTION:A substrate plating layer of Ni-base metal is formed on the surface of a connector base body of copper alloy, etc., and a thin plating layer of gold or gold alloy is formed thereon. Since the gold plating layer contains many pinholes and the corrosion resistance is poor, the layer is dipped in a processing soln. contg. 10-1000ppm cyclic nitrogen compd. as an inhibitor and having an org. solvent soln. contg. 0.1-5% base-oil component such as paraffin wax on the surface and electrolyzed as an anode at 0.1-5V to oxidize the Ni- base substrate metal at the bottom of the pinhole, and the Ni reacts with the inhibitor to form a complex compd. which fills the pinhole. When the sealed material is pulled up from the processing soln., the base-oil component is adsorbed on the entire surface, and the pinhole is sealed and the lubricity of the gold-plate surface is improved.

Description

Detailed Description of the Invention

[0001]

The present invention relates to gold or gold having a base material made of a metal material such as copper alloy, iron, stainless steel, high nickel alloy, etc. and having nickel or nickel-containing alloy plating applied as a base. The present invention relates to a sealing treatment method for an alloy plated material and a connector contact subjected to the sealing treatment. Sealing treatment liquid with excellent lubricity, high corrosion resistance even with thin gold and gold alloy plating, and long-term stability of electrical contact performance,
The present invention relates to a sealing method and a contact that has been sealed.

[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. The connectors used in so-called industrial electronic devices that require a high degree of reliability such as computers and communication devices are those that are plated with a spring copper alloy such as phosphor bronze or beryllium copper as a base material and are gold plated. It is commonly used. These connectors that require a high degree of reliability are required to have high corrosion resistance, long-term stability of electrical contact performance, and high lubricity, that is, low insertion / removal force when inserting / removing the connector. ing. By the way, since gold is expensive, various methods have been adopted for the purpose of reducing the connector manufacturing cost. A typical method therefor is to reduce the thickness of gold plating. However, there is a problem that as the thickness of gold plating is reduced, the number of pinholes in the coating increases exponentially and corrosion resistance is significantly reduced. One of the methods for solving this problem is sealing treatment. That is, the gold-plated surface is treated with various inorganic or organic chemicals,
The purpose is to close the pinhole and improve the corrosion resistance. There are organic and water-based sealing treatments. The organic type is effective in improving lubricity, but the corrosion resistance is inferior to that of the water type. Further, in the organic system, a halogen-based organic solvent is generally used as the solvent, which causes a problem of environmental pollution. The chromate method is a typical water-based method, which is effective but may cause an increase in contact resistance, and has a problem of environmental pollution. In addition, since the solubility of the lubricating components added to conventional organic sealing treatment liquids such as paraffin in water systems is low, the gold-plated material that has been sealed in water systems has low lubricity and impairs the mating and unmating properties of the connector. there were.

[0003]

Therefore, there is a need for a sealing treatment liquid and a sealing treatment method capable of simultaneously improving the lubricity as well as the corrosion resistance and long-term stability of the electrical contact performance of the gold plated material. Has become. An object of the present invention is to provide a sealing treatment liquid and a sealing treatment method using the same which can satisfy such requirements, and also to provide a connector treated by the same. is there.

[0004]

In view of the above situation, the inventors of the present invention have made earnest studies and, as a result, have invented a sealing method and a sealing-processed connector contact shown below. That is, the present invention relates to (1) a method for sealing a gold or gold alloy plated material having nickel or an alloy plating containing nickel as a base material on a base metal, and forming a chelate with nickel or a base metal as an inhibitor. The total amount of one or more of the cyclic nitrogen compounds is 10
A plating solution is prepared by floating an organic solvent solution containing 0.1 to 5.0 wt% of paraffin wax or petrolatum as a base oil component on an aqueous solution containing 1000 ppm to 1000 ppm. A method for sealing a gold or gold alloy plated material, which is carried out in the range of 0.1 to 5.0 V between electrodes E for direct current electrolysis as an anode, and (2) a connector contact sealed by the above method. Is. Also,
In other words, the sealing treatment method of the present invention is also a method for producing a gold-plated material such as a connector contact having a sealing treatment.

The present invention is a sealing treatment method for simultaneously providing a rust preventive effect and a lubricating effect of a gold plated material. By holding the electrode potential of the material to be treated in the oxidized area of nickel which is the base plating and subjecting it to direct current electrolysis, the nickel that is the base metal inside the pinhole of the gold plating is oxidized and the nickel reacts with the inhibitor to form a complex. It has a rust preventive effect by filling the compound in the pinhole, and when pulling the material to be treated from the sealing treatment liquid, it must pass through the organic solvent solution containing the base oil component floating on the inhibitor aqueous solution. At this time, the base oil component is adsorbed on the surface of the gold plating to have a lubricating effect. That is,
INDUSTRIAL APPLICABILITY The present invention is a method capable of exerting the effects of both the conventional organic sealing treatment and the aqueous sealing treatment. In the DC electrolysis, the inter-electrode voltage E between the material to be treated as the anode and the counter electrode is set to 0.1 to 5.0 V because the rustproofing effect is remarkably reduced at a voltage of less than 0.1 V. . Also,
This is because if the voltage exceeds 5.0 V, the rust preventive film becomes thick and the contact resistance increases. Examples of the cyclic nitrogen compound which can be used as an inhibitor in the present invention to form a chelate compound with a base metal such as copper or nickel:
For example, a benzotriazole compound represented by the following formula (1), an indazole compound represented by the following formula (2), a benzimidazole compound represented by the following formula (3), and an indole compound represented by the following formula (4). ,
A 1,3,5-triazinethiol compound represented by the following formula (5) and a mercaptobenzothiazole compound represented by the following formula (6) are effective.

[0006]

[Chemical 1]

(In the formula, R ₁ represents hydrogen, alkyl, or substituted alkyl, and R ₂ represents alkali metal, hydrogen, alkyl,
Represents a substituted alkyl)

[0008]

[Chemical 2]

(In the formula, R ₁ represents hydrogen, alkyl or substituted alkyl, and R ₂ represents alkali metal, hydrogen, acyl, alkyl or substituted alkyl)

[0010]

[Chemical 3]

(Wherein R ₁ represents hydrogen, alkyl or substituted alkyl, and R ₂ represents alkali metal, hydrogen, acyl, alkyl or substituted alkyl)

[0012]

[Chemical 4]

(Wherein R ₁ represents hydrogen, alkyl or substituted alkyl, R ₂ represents a carboxyl group, an alkali metal,
Represents hydrogen, alkyl, substituted alkyl)

[0014]

[Chemical 5]

(Wherein R ₁ represents —SH, or an amino group substituted with an alkyl group or an aryl group, and M ₁ ,
M ₂ represents hydrogen or an alkali metal. )

[0016]

[Chemical 6]

(Wherein R ₁ represents hydrogen, alkyl, substituted alkyl or halogen, R ₂ represents an alkali metal, hydrogen,
Alkyl, substituted alkyl, and substituted amino group are represented) The alkyl represented by R ₁ or R ₂ in the benzotriazole-based compound represented by the formula (1) is, for example, a straight chain having 1 to 10 carbon atoms, preferably 1 to 3 carbon atoms. A straight or branched alkyl is used. The substituent is preferably a carboxyl group or an alkali metal salt thereof. R
_{When 2} represents an alkali metal, sodium, potassium and lithium are preferred. Particularly preferable specific examples are, for example,

[0018]

[Chemical 7]

There are, for example,

The alkyl represented by R ₁ or R ₂ in the indazole compound represented by the above formula (2) is, for example, a linear or branched alkyl having 1 to 10 carbon atoms, preferably 1 to 3 carbon atoms. Used. As the substituent, for example, phenyl, carboxyl group, alkali metal salt thereof and the like are preferable. When R ₂ represents an acyl group, it is preferably an acetyl group or a benzoyl group. When R ₂ represents an alkali metal, sodium, potassium and lithium are preferable. Specific examples of particularly preferable indazole-based compounds include, for example,

[0021]

[Chemical 8]

There are, for example,

The alkyl represented by R ₁ and R ₂ in the benzimidazole compound represented by the above formula (3) is, for example, a linear or branched alkyl having 1 to 10 carbon atoms, preferably 1 to 3 carbon atoms. Is used. The substituent is preferably a carboxyl group or an alkali metal salt thereof. When R ₂ represents an acyl group, it is preferably an acetyl group, a benzoyl group or the like. When R ₂ represents an alkali metal, sodium, potassium and lithium are preferable. Specific examples of particularly preferable benzimidazole compounds include, for example,

[0024]

[Chemical 9]

There are, for example,

Examples of the alkyl represented by R ₁ and R ₂ in the indole compound represented by the formula (4) include linear or branched alkyl having 1 to 10 carbon atoms, preferably 1 to 3 carbon atoms. Used. As the substituent,
Carboxyl groups and their alkali metal salts are preferred.
When R ₂ represents an alkali metal, it is preferably sodium, potassium or lithium. If a particularly preferred specific example of the indole compound is given,

[0027]

[Chemical 10]

Etc.

The alkyl substituent of the substituted amino group represented by R ₁ in the 1,3,5-triazinethiol compound represented by the above formula (5) has, for example, 1 to 30 carbon atoms,
Preferably 4 to 18 linear or branched alkyl are used. As the aryl substituent, for example, phenyl, tolyl and the like are preferable. When M ₁ and M ₂ represent an alkali metal, preferred are sodium, potassium and lithium. If the particularly preferred specific examples of the 1,3,5-triazinethiol compound are given,

[0030]

[Chemical 11]

Etc.

In the mercaptobenzothiazole compound represented by the formula (6), the alkyl represented by R ₁ and R ₂ has, for example, 1 to 10 carbon atoms, preferably 1 carbon atom.
~ 3 straight-chain or branched alkyl, and the alkyl substituent includes a carboxyl group, an alkali metal salt thereof, fluorocarbon, and the like. Further, as the substituted amino group, (C ₄
H _{9) 2} N-and the like are preferable. As the alkali metal, sodium, potassium and lithium are preferable.

Particularly preferred mercaptobenzothiazole compounds are:

[0034]

[Chemical 12]

The total amount of these inhibitors is 10 to 100
The reason for setting 0 ppm is that the sealing treatment function is low at a concentration of less than 10 ppm, and the contact resistance increases at a concentration of more than 1000 ppm. The paraffin wax used as a base oil component, which is another essential component of the present invention, is a saturated hydrocarbon mixture having a molecular weight of about 300 to 500, which is mainly composed of a linear hydrocarbon having an average carbon number of about 20 to 35. is there. Petrolatum is a jelly-like semi-solid wax obtained from petroleum, and is an ointment-like petroleum wax obtained by solvent dewaxing, centrifugation, etc. from a vacuum distillation residue.
The total amount of these base oil components is set to 0.1 to 5.0 wt% because the lubricity improving effect is low at a concentration of less than 0.1 wt% and the contact resistance increases at a concentration of more than 5.0 wt%. This is because.

The solvent used in the organic solvent solution can be appropriately selected from known organic solvents and is not particularly limited. Examples thereof include petroleum-based solvents such as toluene and xylene, alcohol-based solvents such as isopropyl alcohol, and paraffin-based solvents such as normal decane. In the present invention, it is sufficient that the solution of the base oil component in the organic solvent floats on the aqueous solution of the inhibitor in a thickness of about 1 to 10 mm. When the sealing treatment is performed after plating at the stage of a raw material such as a wire material, a plate material, a strip material, it is also effective to perform the sealing treatment with the sealing treatment liquid and the sealing treatment method of the present invention after pressing the plated product. Even in the case of metallic materials that have been subjected to sealing treatment after plating, in the process of washing the press oil and other substances that have adhered in the subsequent pressing process,
The effect of the sealing treatment may decrease. Therefore, the sealing treatment again becomes effective. It is also possible to perform plating and sealing treatment after pressing.

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. Therefore, the present invention also includes a connector processed by the sealing method of the present invention. The metal material serving as the plating base material in the present invention can be appropriately selected according to the required characteristics of the copper, brass, phosphor bronze, titanium copper, various copper alloys such as beryllium copper, iron, stainless steel, high nickel alloy, etc. , There is no limit. A known plating method such as electroplating, electroless plating, or dry plating such as CVD or PVD can be applied to the plating method of the plating material, and is not limited. Further, known methods can be applied to the plating conditions. The gold alloy plating is gold-based alloy plating and is appropriately selected depending on the application. Hard plating containing a small amount of cobalt is widely used for connector applications in order to improve wear resistance. The undercoat is generally nickel, nickel alloyed with 80 to 90% of palladium, nickel alloyed with 60 to 80% of cobalt, or the like. It is valid.

[0038]

The present invention will be described in detail below with reference to examples. Thickness 0.2m of phosphor bronze for spring (C5210-H)
Using the cold rolled material of m, the male and female continuous terminals were press-molded. These were electroplated through a reel-to-reel continuous electroplating line. In the plating line, after degreasing and pickling, 1 μm with Watt bath
Nickel plating, or 0.5 μm Pd80% -Ni20% alloy plating with an ammonia-based plating solution, and gold or gold-cobalt alloy 0.1 μm on it.
The contact portion was partially plated with a thickness of m. Further, in the continuous plating line, a sealing treatment step was provided after gold plating, and the sealing treatment was performed by inserting a continuous terminal. After the surface-treated male and female terminals were cut from the carrier part and the lead wires were pressure-bonded, they were fitted and subjected to an evaluation test.

Contact resistance is DC 10 mA, open-circuit voltage 200.
It was measured at mV. The lubricity was evaluated by measuring the insertion / extraction force of the connector terminal after the treatment. 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 Table 1.

[0040]

[Table 1]

Note 1) However, the abbreviations of plating types and sealing treatment liquids in the table are as follows. N1: Ni N2: Pd-Ni K1: Au K2: Au-Co A-1: Benzotriazole compound represented by the above formula (1) (R ₁ = R ₂ = H) A-2: The above formula (2) Indazole-based compound (R ₁ = R ₂ = H) A-3: Benzimidazole-based compound (R ₁ = R ₂ = H) represented by the formula (3) A-4: In the formula (4) indole compound represented _{(R 1 = R 2 = H} ) A-5: formula (5) represented by 1,3,5-triazine-thiol compound _{(R 1 = N (C 4} H 9), M 1 = H,
M ₂ = Na) A-6: mercaptobenzothiazole compound represented by the formula (6) (R ₁ = R ₂ = H) B-1: paraffin wax B-2: petrolatum Note 2) The criteria for the test are: It is as follows.

Initial contact resistance, contact resistance after corrosion test (average value of n = 5) ○: 10 mΩ or less △: 10 to 20 mΩ ×: 20 mΩ or more Appearance after corrosion test ○: No corrosion product Δ: Corrosion product Dotted x: Corrosion points are observed on the entire surface Lubricity (insertion / removal force) ○: Insertion force per contact pin 290g or less Extraction force 220g or less △: Insertion force per contact pin 290-300g
Removal force 220-230g ×: Insertion force per contact pin is 300g or more Removal force is 230g or more

[0043]

As described above, the gold-plated product which has been subjected to the sealing treatment according to the present invention has a low contact resistance immediately after the sealing treatment and has a long-term stability of the contact performance (high corrosion resistance, even in a severe corrosive environment). It has a low contact resistance value) and has an advantage of high lubricity.

Claims (2)

[Claims] 1. A method for sealing a gold or gold alloy plated material, which comprises a base metal such as nickel or an alloy plating containing nickel as a base material, and a chelate-forming cyclic nitrogen with nickel or a base metal as an inhibitor. 10 to 1000 pp in total of one or more compounds
paraffin wax and petrolatum as a base oil component on the aqueous solution containing 0.1 to 5.
Gold for which direct-current electrolysis is carried out in a range of 0.1 to 5.0 V between electrodes during direct current electrolysis using the plated material as an anode in a sealing treatment solution containing a 0 wt% organic solvent solution. Alternatively, a method for sealing a gold alloy plated material. 2. A connector contact, which has been subjected to a sealing treatment by the method according to claim 1.