JPH08260193A - Sealing method of gold plated material - Google Patents

Abstract

PURPOSE: To produce a plated material excellent in corrosion resistance and lubricity by electrolyzing a material as an anode in a specific solution and, after that, applying a solution of a specific component on the plated material. CONSTITUTION: A material is electrolyzed as an anode in an aq. solution containing 0.01-1wt.% one or more kinds selected from a benzotriazole based compound expressed formula I, a mercaptobenzothiazole based compound expressed by formula II and a triazine based compound expressed by formula III. After that, a solution consisting essentially of 0.05-2wt.% one or more kinds of fatty acids expressed the formula R7 COOH and 0.05-2wt.% one or two kinds selected from alkyl phosphoric esters expressed by a specific formula is applied on the taken-out plated material. In the formulas, R1 expresses hydrogen, an alkyl group or the like, R2 expresses an alkali metal, a substituted alkyl group or the like, R3 expresses an alkali metal or the like, R4 expresses SH and each of R5 and R6 expresses NH2 , SH or the like. As a result, the sealing solution containing no environmental contaminant can be obtained.

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 a gold or gold alloy plated material having nickel or nickel-containing alloy plating of a metal material such as iron alloy, iron, stainless steel, high nickel alloy as an underlayer. It is a thing.

[0002]

2. Description of the Related Art A connector, which is a connecting component for electronic equipment, is generally made of brass or phosphor bronze, which is plated with nickel underlayer and further plated with gold.
However, since gold is expensive, various methods have been adopted in order to reduce the connector manufacturing cost. A typical method thereof is a method of reducing 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 film exponentially increases and the corrosion resistance significantly decreases. One of the methods for solving this problem is sealing treatment. That is, the gold plating surface is treated with various kinds of inorganic or organic chemicals to close the pinholes and improve the corrosion resistance. There are two types of sealing liquids, organic and water-based. Since a halogen-based organic solvent is generally used as a solvent in an organic system, the use of an organic sealing treatment liquid is currently greatly restricted due to problems such as ozone layer destruction. On the other hand, in the water system, since water is used as a solvent, there is no problem in terms of environmental pollution, but since it is not possible to use a lubricant such as paraffin, which is hardly soluble in the water used in conventional organic sealing treatment liquids, The treated plating had low lubricity and had a problem that the durability of the connector was inferior to that of the solvent-based plating.

[0003]

Therefore, there is a need for a pore-sealing solution and a pore-sealing method that have no environmental pollution and have the same or higher level of pore-sealing effect as conventional ones. The present invention aims to provide an improved method for sealing treatment which can meet such requirements.

[0004]

As a result of the research conducted by the present inventor to solve the above problems, the inventors have invented the following surface treatment method. That is, the present invention provides: (1) In a method for sealing a gold or gold alloy plated material, which comprises a metal material containing nickel or an alloy containing nickel as an undercoat, a step of the general formula (1)
A benzotriazole compound represented by the general formula (2)
0.001 to a total of one kind or two or more kinds selected from the group consisting of the mercaptobenzothiazole-based compound represented by and the triazine-based compound represented by the general formula (3).
After electrolyzing the material as an anode in an aqueous solution containing 1 wt%, the plated material is taken out of the aqueous solution,
In step 2, one or more fatty acids represented by the general formula (4) are added in a total amount of 0.05 to 2 wt% and an alkyl selected from the group represented by the general formulas (5) and (6). One or two phosphate ester in total 0.05
A surface treatment method, which comprises applying a liquid containing 2 wt% as an essential component to the plating material.

[0005]

Embedded image

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

[0007]

[Chemical 6]

(In the formula, R ₃ represents an alkali metal or hydrogen)

[0009]

[Chemical 7]

[Wherein R ₄ is —SH, an amino group substituted with an alkyl group or an aryl group, or an alkyl-substituted imidazolylalkyl, and R ₅ and R ₆ are —NH ₂ , —SH or —S
M (M represents an alkali metal) represent] R ₇ -COOH (4) (wherein, R ₇ represents a 10 to 20 saturated and unsaturated chain hydrocarbon having a carbon number)

[0011]

Embedded image

(Wherein R ₈ represents alkyl or substituted alkyl, M represents hydrogen or alkali metal) (2) Electrolysis voltage between electrodes 1 to 5 V, current density 0.1 A / m
The sealing treatment method according to (1) above, which is carried out at ² or more. (3) The seal according to (1) or (2) above, wherein the anode is a processed gold or gold alloy plated material having nickel or an alloy containing nickel as a base plating in a metal material. This is a hole treatment method.

In the aqueous solution used in step 1 of the sealing treatment method of the present invention, one or two compounds selected from the compounds shown below as an inhibitor, that is, benzotriazole compounds, mercaptobenzothiazole compounds and triazine compounds, are used. More than one species are selected and added to the treatment liquid. These inhibitors react with nickel, which is the base metal inside the gold-plated pinhole, to form a complex compound, and the complex compound fills the pinhole.
As a result, the corrosion resistance of gold plating is improved. The benzotriazole-based compound used in the present invention has the general formula (1)

[0014]

[Chemical 9]

(In the formula, R ₁ represents hydrogen, alkyl or substituted alkyl, and R ₂ represents alkali metal, hydrogen, alkyl,
Represents a substituted alkyl). Among the compounds represented by the general formula (1), preferred examples include, for example, benzotriazole (R ₁ and R ₂ are both hydrogen), 1-methylbenzotriazole (R ₁ is hydrogen, R ₂
Is methyl), tolyltriazole (R ₁ is methyl, R ₂ is hydrogen), 1- (N, N-dioctylaminomethyl) benzotriazole (R ₁ is hydrogen, R ₂ is N, N-dioctylaminomethyl), etc. is there.

The mercaptobenzothiazole compound used in the present invention has the general formula (2)

[0017]

[Chemical 10]

(In the formula, R ₃ represents an alkali metal or hydrogen). Preferred examples of the compound represented by the general formula (2) include mercaptobenzothiazole, mercaptobenzothiazole sodium salt, and mercaptobenzothiazole potassium salt. In the general formula (2), when R ₃ is an alkali metal, the mercaptobenzothiazole compound can be easily dissolved in water. The triazine-based compound has the general formula (3)

[0019]

[Chemical 11]

[Wherein R ₄ is —SH, an amino group substituted with an alkyl group or an aryl group, or an alkyl-substituted imidazolylalkyl, and R ₅ and R ₆ are —NH ₂ , —SH or —S
M (M represents an alkali metal)]. Preferred examples of the compound represented by the general formula (3) include the following.

[0021]

[Chemical 12]

Alternatively, there is an alkali metal salt such as Na or K. In the general formula (3), R ₅ and R ₆ are −
In the case of SM, the triazine compound can be easily dissolved in water. The amount of inhibitor added is 0.001 to 1w
If the amount is less than 0.001 wt%, the effect of sealing treatment is not observed, and if it exceeds 1 wt%, the contact resistance is adversely affected. In step 1, the plated product is immersed in the treatment liquid, and the material is used as an anode and a direct current or a pulse current is passed between the electrodes. By making the plated product an anode, the inhibitor in the solution is adsorbed to the base metal inside the pinhole of the plated product and prevents its corrosion. The inter-electrode voltage during electrolysis is in the range of 1 to 5 V, and if the inter-electrode voltage is less than 1 V, no sufficient effect can be obtained, and if it exceeds 5 V, the plating film is more dissolved and the sealing treatment effect cannot be obtained. Current density is 0.1A /
If it is m ² or more and less than 0.1 A / m ² , the effect of sealing treatment cannot be obtained. The processing time is preferably 1 to 10 seconds. After the treatment, the plated material is taken out of the aqueous solution and the treatment of step 2 is performed.

The liquid used in step 2 of the sealing treatment method of the present invention is one or more selected from fatty acids as the first essential component and added to the treatment liquid. Fatty acids contribute to improving the lubricity of gold-plated products. The fatty acid used in the present invention is represented by the general formula (4) R ₇ —COOH (4) (wherein R ₇ represents a saturated or unsaturated chain hydrocarbon having 10 to 20 carbon atoms). This general formula (4)
Preferred examples of the compound represented by are lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid and the like. The total amount added is in the range of 0.05 wt% to 2 wt%, and 0.0
If it is less than 5 wt%, a sufficient lubricating effect cannot be obtained, and 2 wt%
If it exceeds the range, the appearance of the material after the sealing treatment is adversely affected.

In the liquid used in the sealing treatment step 2 of the present invention, one or more compounds selected from the compounds shown below as the second essential component, that is, monoalkyl phosphates and dialkyl phosphates are used. Selectively added,
It is added to the processing solution. These alkyl phosphates function as an emulsifier and a lubricant for lubricants.
The monoalkyl phosphate used in the present invention has the general formula (5):

[0025]

[Chemical 13]

(In the formula, R ₈ represents alkyl and substituted alkyl, M represents hydrogen and alkali metal). Preferred examples of the compound represented by the general formula (5) include lauryl acid phosphoric acid monoester. The dialkyl phosphate ester has the general formula (6)

[0027]

Embedded image

(In the formula, R ₈ represents alkyl and substituted alkyl, M represents hydrogen and alkali metal). Preferred examples of the compound represented by the general formula (6) include lauryl acid diphosphate. The total amount of alkyl phosphate ester added is 0.05
The content is in the range of 2 wt% to 2 wt%, and if it is less than 0.05 wt%, the emulsifying effect cannot be obtained, and if it exceeds 2 wt%, the solderability is adversely affected. The solvent of the liquid used in step 2 can be appropriately selected from water and halogen-free organic solvents such as ethanol, acetone, and normal paraffin. When the solvent is water, heating the temperature of the solution to 40 to 80 ° C. accelerates the emulsification of the components into water and further facilitates the drying of the material after the sealing treatment. In step 2, the above-mentioned liquid is applied to the gold-plated material, but the application method may be any method such as dipping or spraying.

In the present invention, the shape of the plated product is a plate
It has been found that, regardless of whether it is a strip or a pressed part, in both step 1 and step 2, if it is a continuous line immediately after plating, that is, if it is a continuous line, it is highly effective to enhance various functions of the sealing treatment. . Further, it is also effective to subject the plated product to a sealing treatment with the sealing treatment liquid of the present invention after processing such as pressing. Even if the metal material is subjected to the sealing treatment after plating, most of the sealing treatment function is lost in the step of washing the press oil adhered in the subsequent press working. Therefore, the sealing treatment again becomes effective.

[0030]

The present invention will be described in detail below with reference to examples. Male and female continuous terminals were press-molded using a cold-rolled material of spring phosphor bronze (C5210) having a thickness of 0.2 mm. These were electroplated through a continuous reel-to-reel plating line. In the plating line, after degreasing and pickling, 1 μm nickel plating in Watts bath or 0.5 μm P in alkaline bath
d80% -Ni20% alloy plating was performed, and gold or gold-cobalt alloy was plated on the contact portion to a thickness of 0.1 μm. Further, in the continuous plating line, a sealing treatment step was provided after gold plating, and a continuous terminal was inserted and treated. The conditions of step 1 are a treatment liquid temperature of 25 ° C., a voltage between electrodes of 2 V, a current density of 0.6 A / m ² , and a treatment time of 5 seconds. The conditions of step 2 are a treatment liquid temperature of 60 ° C. (solvent is water) and an immersion time. 5 seconds. The male and female terminals thus sealed were cut from the carrier part and the lead wires were crimped, and then fitted to each other and subjected to an evaluation test.

Contact resistance is DC 10 mA, open voltage 200
It was measured at mV. The lubricity was evaluated by the insertion / removal force of the connector terminal after the treatment. The corrosion resistance was evaluated by performing a sulfurous acid gas corrosion test under the following conditions and observing the surface of the sample after the test and measuring the contact resistance. Gas composition: SO ₂ 10 ppm Temperature: 40 ± 2 ° C. Humidity: 80 ± 5% RH Time: 240 hours Table 1 shows the test results.

[0032]

[Table 1]

Note 1) However, the abbreviations for the sealing treatment liquid in the table are as follows. A-1 Benzotriazole A-2 Sodium salt of mercaptobenzothiazole A-3 Sodium salt of 1,3,5-triazinethiol B-1 Oleic acid C-1 Lauryl acid phosphoric acid monoester (phosphoric acid monolauryl ester) C -2 Lauryl acid phosphoric acid diester (phosphoric acid dilauryl ester) Note 2) Test criteria (1) Initial contact resistance, contact resistance after corrosion test ○: 10 mΩ or less △: 10 to 20 mΩ ×: 20 mΩ or more (2) Appearance after corrosion test ○: The number of corrosion points is 10 or less in the range of 5 cm square of the 50 times enlarged photograph. Δ: The number of corrosion points is 10 to 50 in the range of 5 cm square of the 50 times enlarged photograph. The number of corrosion points is 50 or more in the 5 cm square area of the 50 times magnified photograph. (3) Lubricity (insertion / extraction force) ○: Insertion force 100 g or less per pin Removal force 50g
Below Δ: Insertion force per pin of 100 to 150 g, removal force 5
0 to 100g ×: Insertion force per pin is 150g or more, removal force is 100
g or more

[0034]

As described above, the sealing treatment liquid of the present invention does not contain a substance polluting the environment, and the gold and gold alloy plated materials treated with this liquid have excellent corrosion resistance and lubricity. Have.

Claims (3)

[Claims] 1. A method for sealing a gold or gold alloy plated material, which comprises a metal material containing nickel or an alloy containing nickel as an undercoat, the step 1 comprising a benzotriazole-based compound represented by the following general formula (1): Compound,
0.001 to 1 wt% in total of one kind or two or more kinds selected from the group consisting of a mercaptobenzothiazole compound represented by the following general formula (2) and a triazine compound represented by the following general formula (3) After electrolyzing the material as an anode in an aqueous solution, the plating material is taken out from the aqueous solution, and then, as Step 2, the following general formula (4)
One or more of the fatty acids represented by
5 to 2 wt% and the following general formula (5) and general formula (6)
1 alkylphosphoric acid ester selected from the group
A sealing treatment method, characterized in that a liquid containing 0.05 to 2 wt% of one or two kinds as an essential component is applied to the plating material. Embedded image (In the formula, R ₁ represents hydrogen, alkyl, or substituted alkyl, and R ₂ represents alkali metal, hydrogen, alkyl, or substituted alkyl.) (In the formula, R ₃ represents an alkali metal or hydrogen) [In the formula, R ₄ is —SH, an amino group substituted with an alkyl group or an aryl group, or an alkyl-substituted imidazolylalkyl, and R ₅ and R ₆ are —NH ₂ , —SH or —SM (M represents an alkali metal. ) represent] R ₇ -COOH (4) (wherein, R ₇ represents a 10 to 20 saturated and unsaturated chain hydrocarbon having a carbon number) embedded image (In the formula, R ₈ represents alkyl or substituted alkyl, M represents hydrogen or alkali metal) 2. Electrolysis is carried out with a voltage between electrodes of 1 to 5 V and a current density of 0.
The sealing treatment method according to claim 1, which is carried out at 1 A / m ² or more. 3. The sealing hole according to claim 1, wherein the anode is formed by processing a gold or gold alloy plated material having nickel or an alloy containing nickel as a base plating on a metal material. Processing method.