KR101582870B1 - Silver carbon plate-coating for coating silver plating, Coating method thereof, and metal contacting terminal containing that - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon-coated coating liquid for silver-plating coating, and a coating method using the same, wherein the metallic carbon- Mechanical and / or electrical properties can be improved, and in particular, corrosion resistance is excellent.

Description

Technical Field [0001] The present invention relates to a carbon coating solution for silver plating, a method for coating the same, and a metal contact terminal comprising the same,

In order to improve the mechanical and / or electrical properties of the silver contacted metal contact terminal, the present invention provides a method of coating a silver carbon coating liquid for preventing wear and discoloration on the surface of silver plating, .

The contact terminal is used between the movable part and the fixed part in an electronic device or an electric device having a mechanically operating conductive part such as a circuit breaker, a disconnecting contactor, a load switch or a connecter.

The contact resistance of the contact terminal becomes unstable and the resistance becomes higher when the contact point for energizing is slid. At this time, when the contact resistance is increased, the contact portion is heated by the heat generated by the electrical resistance, whereby oxidation phenomenon occurs in the metal used as the contact terminal, particularly copper or copper alloy, And the oxidation phenomenon is further promoted. In order to prevent such an oxidation phenomenon, the surface of the contact terminal is plated. Such silver plating of the contact terminal is mainly performed using silver (Ag), and various attempts have been made to improve the physical properties of silver plating.

For example, Korean Patent Publication No. 10-2006-0127340 discloses a copper or copper alloy contact method using a plating solution containing sulfuric acid, ammonium sulfate, citric acid, ferrous sulfate, ammonia water, particulate carbon, ruthenium, The silver plating solution of such a composition is environmentally friendly in that it does not use a cyanide compound, but has a problem that the manufacturing cost of the plating solution becomes too high.

The present invention relates to a metal contact terminal which can provide a metal contact terminal having a low manufacturing cost and excellent mechanical and / or electrical properties while using a conventional silver plating solution, and a carbon coating liquid for silver plating for this purpose, A method of forming a coating layer, and a metal contact terminal formed with such a carbon coating layer.

In order to solve the above-described problems, the present invention relates to a carbon-coating coating solution for silver plating, which comprises cyanine silver, blue phosphorus, carbonic acid, graphite powder, a dispersion agitator and a surfactant.

In one preferred embodiment of the present invention, the silver-plated coating liquid of the present invention comprises 100 to 200 parts by weight of blue tar, 10 to 70 parts by weight of carbon black, 300 to 550 parts by weight of graphite powder, 10 to 100 parts by weight of the dispersion agitator, and 25 to 70 parts by weight of the surfactant.

As a preferred embodiment of the present invention, in the silver-plated coating liquid of the present invention, the graphite powder may have an average particle diameter of 0.5 to 2 μm.

As a preferred embodiment of the present invention, in the silver-plated coating liquid of the present invention, the surfactant may be at least one selected from the group consisting of an alkyltrimethylammonium compound, a dialkyldimethylammonium compound, a trialkylmethylammonium compound, a tetraalkylammonium compound, At least one cationic interface selected from a diamino dimethyl ammonium compound, a polydiaryl dialkyl ammonium compound, a polyacrylamide compound, a polyethyleneimine diammonium compound, a benzyl compound, a pyridinium compound and a polyvinyl pyridine compound And an activator.

As a preferred embodiment of the present invention, in the silver-plated coating liquid of the present invention, the dispersion agitating agent may be characterized by containing polyoxylethylene lauryl ether, ethylene glycol monobutyl ether, and ethylene glycol.

In a preferred embodiment of the present invention, the dispersion agitator comprises the polyoxylethylene lauryl ether, the ethylene glycol monobutyl ether and the ethylene glycol in a weight ratio of 1: 0.5 to 1: 1 to 2 .

In another preferred embodiment of the present invention, the carbonaceous coating solution of the present invention may have a pH of 10 to 15.

According to another aspect of the present invention, there is provided a method of coating a silver-plated carbon coating layer with the above-described various types of silver-plated carbon coating solution, comprising the steps of: preparing a metal contact terminal having a silver plating layer; And coating the surface of the silver plating layer with the silver plating solution of various types described above to form a silver plating layer.

As a preferred embodiment of the present invention, in the method for forming a silver-plated carbon coating layer of the present invention, the temperature of the silver-plated carbon coating liquid may be 25 ° C to 50 ° C.

As a preferred embodiment of the present invention, in the method for forming a silver-plated carbon coating layer of the present invention, the step of preparing the metal contact terminal comprises plating the silver contact terminal with a silver plating solution to form a silver plating layer, The cyanide may be characterized by containing 100 to 200 parts by weight of blue tar, 10 to 70 parts by weight of the carbon black, and 30 to 60 parts by weight of the brightener, based on 100 parts by weight of the mixture.

In one preferred embodiment of the present invention, the brightener may include a selenium compound, a tartrate, and a surfactant. The brightener may include 5-20 parts by weight of a tartrate, 10 parts by weight.

In one preferred embodiment of the present invention, the brightener is a cellulose brightener (brightener 1) comprising 10 to 20 parts by weight of stannate and 1 to 5 parts by weight of surfactant, based on 100 parts by weight of the cellulose composition. (Brightener 2), which is contained in an amount of 5 to 10 parts by weight of stannate and 5 to 8 parts by weight of a surfactant, based on 100 parts by weight of the cellulose compound, at a weight ratio of 1: 0.1 to 0.3 have.

In another preferred embodiment of the present invention, in the method for forming a silver-plated carbon coating layer of the present invention, the metal contact terminal formed with the silver plating layer may include: a first step of degreasing the metal contact terminal; Washing the degreased metal contact terminal with water; A third step of acid washing and washing the washed metal contact terminals; A fourth step of copper-plating the re-washed metal contact terminals; 5 steps of washing the copper-plated metal contact terminals with water, Ag strike treatment, and then re-aging; Forming a silver plating layer on the surface of the metal contact terminal re-aged in step 5 by plating with the silver plating solution, followed by washing with water and drying.

In another preferred embodiment of the present invention, the step 6 may further include coating the surface of the silver plated layer of the metal bonding terminal having the silver plating layer formed thereon with water with a discoloration preventing solution to form a discoloration preventing layer after washing with water have.

As another preferred embodiment of the present invention, in the method for forming a silver-plated carbon coating layer of the present invention, the surface of the silver-plated carbon coating layer is coated with a discoloration preventing solution to form a discoloration preventing layer at 5 캜 to 20 캜 The method may further comprise:

In another preferred embodiment of the present invention, the degreasing in the first step is performed by degreasing the metal contact terminal with a degreasing solution containing 2 to 5 parts by weight of cyanogen oxide and 2 to 5 parts by weight of caustic soda with respect to 100 parts by weight of the degreasing agent . ≪ / RTI >

In another preferred embodiment of the present invention, the acid treatment in the above three stages is carried out at 30 ° C to 40 ° C in an acidic solution containing 35 to 59% by volume of nitric acid, 40 to 60% by volume of sulfuric acid and 0.5 to 15% And the like.

According to another preferred embodiment of the present invention, the copper plating in the fourth step is performed by copper plating at a copper plating amount of 40 ° C to 60 ° C, a pH of 12.0 to 13 and a current density of 1 to 1.5 mA / dm ² , 50 to 100 parts by weight of a bluing agent 1, 40 to 60 parts by weight of caustic soda, 20 to 50 parts by weight of rochelle salt and 10 to 25 parts by weight of rosorbite per 100 parts by weight of soda have.

In another preferred embodiment of the present invention, the Ag strike in the 5-step is treated with an Ag strike solution at 20 ° C to 35 ° C, and the Ag strike solution contains 2 to 5 g / L of cyanide, 80 to 100 g / And 10 to 25 g / L of carbonic acid.

In another preferred embodiment of the present invention, in the method of forming the silver-plated carbon coating layer of the present invention, the surface of the silver-plated layer and / or the silver plating layer used for forming the anti-fading layer on the surface of the silver- The discoloration preventing solution used for forming the discoloration preventing layer may be characterized by containing 12 to 125 parts by weight of dichromic acid and 25 to 100 parts by weight of caustic soda with respect to 100 parts by weight of carbonic acid. The discoloration preventing liquid has an average temperature of 5 ° C to 20 ° C.

As another preferred embodiment of the present invention, in the method for forming a silver-plated carbon coating layer of the present invention, the drying step may include coating a silver plating layer of a metal bonding terminal having a silver plating layer formed thereon with a discoloration- The method comprising the steps of:

Another aspect of the present invention relates to a metal contact terminal, and it can be characterized in that it includes a silver-carbon-plated coating layer coated by the above-described coating method using the above-described various types of silver-carbon coating liquid.

As a preferred embodiment of the present invention, the metal contact terminal of the present invention is formed by copper plating on the surface of the metal contact terminal; Silver plated layer; And a silver-plated carbon coating layer coated with the silver-plated coating liquid.

In another preferred embodiment of the present invention, the metallic contact terminal of the present invention may further include a discoloration preventing layer on the surface of the silver-plated coating layer.

As another preferred embodiment of the present invention, the metal contact terminal of the present invention may further include a discoloration preventing layer between the silver plating layer and the silver-plated coating layer.

As another preferred embodiment of the present invention, in the metal contact terminal of the present invention, the silver-plated carbon coating layer may have an average thickness of 3 탆 to 10 탆.

In another preferred embodiment of the present invention, the metal contact terminal of the present invention may include a metal contact terminal for electricity or a metal contact terminal for electrons.

When the coating layer is formed of the silver-plated silver coating liquid of the present invention on the silver-plated metal contact terminals, not only the long-term stability in terms of abrasion resistance, lubricity and conductivity of the metal contact terminals is excellent, but also color stability is secured.

1A is a fixed terminal of a metal contact terminal, B is a movable terminal of a metal contact terminal, and Fig. 1B is a cross-sectional view of a metal contact terminal in which a silver plated layer, a silver plated carbon coating layer, As an example, the hatched portion is a portion where a silver carbon-plated coating layer and a discoloration preventing layer are sequentially stacked on one surface of a silver-plated layer, and a portion without a hatched portion is a portion where a silver-plated coating layer is not formed.
FIGS. 2A and 2B are test results of a neutral salt spray test of the metal contact terminal manufactured in Example 1 conducted in Experimental Example 1, which was submitted to the Korea Chemical Fusion Test Institute.

The term " metal contact terminal " used in the present invention means to include a conductive contact terminal such as an electric / electronic contact terminal, a contactor terminal, or the like.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a silver-carbon coating liquid for forming a silver-plated carbon coating layer on one surface of a silver-plated layer of a metal contact terminal having a silver plating layer formed thereon, Cheonghwagari; Carbonic acid; Graphite powder; A dispersion agitator; And a surfactant.

The silver halide silver is introduced for compatibility and adhesion between the silver-plated carbon coating layer and the silver plating layer. The amount of the blueing agent used is 100 to 200 parts by weight, preferably 120 to 180 parts by weight, more preferably 130 to 170 parts by weight, based on 100 parts by weight of the blueing agent. If the amount of the blue phosphorus is less than 100 parts by weight, the silver chloride does not dissolve well, and there may be a problem that the coating of the silver carbon coating coat is cloudy. If the phosphorus phosphorus is used in an amount exceeding 200 parts by weight, It may dissolve too much, and as a result, the coating film may become rough on the surface of the product.

The amount of the silver halide to be coated is 25 to 70 parts by weight, preferably 30 to 60 parts by weight, more preferably 30 to 50 parts by weight, based on 100 parts by weight of the silver halide, If the amount of the carbonic acid is less than 25 parts by weight, the surface of the carbon-coating layer may not be smooth. When the amount of the carbon-coating layer is more than 70 parts by weight, Therefore, it is preferable to use within the above range.

The graphite powder serves as a carbon component and improves mechanical properties such as abrasion resistance of the coating layer. The graphite powder has an average particle diameter of 0.5 to 2 탆, preferably an average particle diameter of 0.5 to 1.5 탆, If the average particle diameter of graphite powder is less than 0.5 탆 or more than 2 탆, graphite powder electrodeposited on the metal contact terminal may cause an abnormality in electric conductivity or electrical resistivity, It is preferable to use graphite powder having an average particle size within the above range. The appropriate amount of the blending is preferably 300 to 550 parts by weight, preferably 300 to 500 parts by weight, more preferably 320 to 450 parts by weight, based on 100 parts by weight of the blending, The effect of improving the abrasion resistance of the backcoat layer can be reduced. If the amount is more than 550 parts by weight, the coating amount may be excessively increased, resulting in a poor coating property and the coating layer may not be uniformly formed.

In addition, the dispersion agitator serves to disperse the graphite powder well in the coating layer and to improve the usability among other compositions. The amount of the dispersion agitator is 10 to 100 wt. Preferably 15 to 80 parts by weight, more preferably 20 to 60 parts by weight, based on 100 parts by weight of the total amount of the dispersing agent. When the amount of the dispersing and stirring agent is less than 10 parts by weight, the graphite powder to be obtained is not uniformly formed However, if it is used in an amount exceeding 100 parts by weight, the use amount thereof may be too much, and the compatibility between the compositions may be deteriorated, so that the physical properties such as abrasion resistance of the coating layer may decrease.

The dispersing and stirring agent may include polyoxylethylene lauryl ether, ethylene glycol monobutyl ether and ethylene glycol, preferably polyoxyethylenelauryl ether, ethylene glycol monobutyl ether and ethylene glycol at a ratio of 1: 0.5 To 1: 1 to 2: 1, more preferably from 1: 0.5 to 0.8: 1.4 to 1.8, by weight. If the weight ratio of the ethylene glycol monobutyl ether is less than 0.5 parts by weight based on the weight of the polyoxyethylenelauryl ether, the dispersibility of the graphite powder may deteriorate and the conductivity, lubricity, and coating formability may deteriorate. The dispersibility of the graphite powder can not be further improved. If the weight ratio of ethylene glycol to the polyoxyethylenelauryl ether is less than 1 part by weight, the effect of improving the compatibility between the coating liquid compositions may be reduced. If the weight ratio of ethylene glycol is more than 2 parts by weight, the abrasion resistance of the coating layer may decrease It is recommended to use it within the above range.

In addition, the surfactant serves to reduce the surface tension of the silver-carbon coating solution to form a uniform coating layer. The cation surfactant is preferably used in combination with an alkyltrimethylammonium compound, a dialkyldimethylammonium compound, Trialkylammonium compounds, tetraalkylammonium compounds, polydiaminodimethylammonium compounds, polydialyldialkylammonium compounds, polyacrylamide compounds, polyethyleneimine diammonium compounds, benzyl compounds, pyridinium compounds Compounds and polyvinyl pyridine-based compounds may be used alone or in combination of two or more. The surfactant may be used in an amount of 25 to 70 parts by weight, preferably 30 to 65 parts by weight, and more preferably 35 to 50 parts by weight, based on 100 parts by weight of the cyanide, wherein the amount of the surfactant If the amount is less than 25 parts by weight, the carbon-plated coating layer may be uneven. If it is used in an amount of more than 70 parts by weight, the coating layer may be formed uniformly, but the moldability may be lowered. good.

The silver-plated carbon coating solution of the present invention preferably has a pH of 10 to 15, preferably a pH of 11 to 14. When the pH is less than 10, the carbon coating layer is uniformly formed on the surface of the silver plating layer When the pH is more than 15, the surface of the carbon-coated coating layer may not be formed cleanly and the coated surface may be roughened. Therefore, there is a problem that the pH It is preferable to adjust the pH of the carbon-coating coating solution.

Hereinafter, a method of forming the silver-plated coating layer on the silver plating layer of the metal contact terminal formed with the silver plating layer using the silver plating solution of the present invention will be described.

The method for forming a silver-plated carbon coating layer of the present invention includes the steps of: preparing a metal contact terminal having a silver plating layer; And coating the surface of the silver plating layer with the silver plating solution to form a silver plating layer on the surface of the carbon plating layer to form a discoloration preventing layer, The method further comprising the steps of:

First, a step of preparing a metal contact terminal having a silver plating layer will be described in detail.

The metal contact terminal may be a metal contact terminal including a metal such as copper (Cu), iron (Fe), aluminum (Al), tin (Sn), tungsten (W)

The metal contact terminal formed with the silver plating layer may include: a first step of degreasing the metal contact terminal; Washing the degreased metal contact terminal with water; A third step of acid washing and washing the washed metal contact terminals; A fourth step of copper-plating the re-washed metal contact terminals; 5 steps of washing the copper-plated metal contact terminals with water, Ag strike treatment, and then re-aging; Forming a silver plating layer on the surface of the metal contact terminal re-aged in step 5 by plating with the silver plating solution, followed by washing with water and drying.

In addition, the method may further include forming a discoloration preventing layer by coating the surface of the silver plating layer of the metal bonding terminal having the silver plating layer formed thereon with water before the drying, , And washing with water. In this case, the discoloration preventing solution may be a conventional discoloration preventing solution for silver plating used in the art. Preferably, the discoloring preventing solution is composed of 12 to 125 parts by weight of dichromic acid per 100 parts by weight of carbonic acid, To 100 parts by weight, and more preferably, the discoloration preventive liquid includes 30 to 90 parts by weight of dichromic acid and 40 to 60 parts by weight of caustic soda with respect to 100 parts by weight of carbonic acid. .

The degreasing in the first step is for removing oil or other foreign matter on the surface of the metal contact terminal. The metal contact terminal is degreased with 2 to 5 parts by weight of selenized soda and 2 to 5 parts by weight of caustic soda with respect to 100 parts by weight of the degreasing agent. Deg.] C. At this time, the degreasing agent may be a general degreasing agent used in the art. After performing degreasing, washing with water may be carried out 2 to 4 times, preferably 3 to 4 times, by a general method used in the industry.

The acid treatment in the above three stages is for peeling the surface of the metal contact terminal primarily by acid treatment of the metal contact terminal degreased with acid solution for 15 to 20 minutes at 30 ° C to 40 ° C, . Particularly, when the metal contact terminal is made of non-iron (brass, new alloy, etc.), the acid solution used for the acid treatment contains 35 to 59 vol% nitric acid, 40 to 60 vol% sulfuric acid, and 0.5 to 15 vol% It is good to do. The acid treatment is carried out at a temperature of 30 ° C to 40 ° C to remove impurities on the surface of the raw material and to peel the surface of the raw material uniformly and uniformly. The acid-treated metal contact terminals are washed with water, and washing with water can be carried out 2 to 4 times, preferably 3 to 4 times, by a general method used in the industry.

The copper plating in the fourth step may be performed using a copper plating solution at a temperature of 40 ° C to 60 ° C and a current density of 1 mA / dm ² to 1.5 mA / dm ^2. If the copper plating temperature is less than 40 ° C, There may be a problem of coming out in a dark, dark red color. If the temperature is higher than 60 ° C, it may cause a problem that the surface of the product may come out roughly while passing the current much. The pH of the copper plating solution is preferably 12.0 to 13.0, more preferably 12.2 to 12.6. If the pH of the copper plating solution is less than 12.0, , and when the pH exceeds 13.0, there is a problem that the coating film is roughly formed on the surface of the product (this phenomenon may be referred to as "coating film rubbing phenomenon"

The amount of the copper plating solution is 50 to 100 parts by weight of a bluing agent 1, 40 to 60 parts by weight of caustic soda, 20 to 50 parts by weight of rochelle salt and 10 to 25 parts by weight of rosorbite per 100 parts by weight of sodium cyanide Preferably 60 to 85 parts by weight of a bluing agent per 100 parts by weight of cyanide soda, 45 to 55 parts by weight of caustic soda, 25 to 40 parts by weight of Rochelle salt and 15 to 20 parts by weight of rosanguard .

The copper-plated metal contact terminal is washed with water, and washing with water is carried out 2 to 4 times, preferably 3 to 4 times, by a general method used in the industry.

The Ag strike in the fifth step can treat the metal contact terminal plated with the Ag strike liquid at 20 캜 to 35 캜 at normal temperature. The Ag strike solution can treat 2 to 5 g / L of blue stain and 80 to 100 g / And 10 to 25 g / L of carbonic acid, and preferably 2 to 4 g / L of blue coloration, 85 to 95 g / L of blue color and 15 to 20 g / L of carbonic acid.

The silver plating solution in step 6 may be a silver plating solution used in the art and a general silver plating method. Preferably 100 to 200 parts by weight of the silver halide, 100 to 200 parts by weight of blue silver halide, 25 to 70 parts by weight A silver plating solution containing 30 to 60 parts by weight of a brightening agent, and more preferably, a silver plating solution containing 140 to 200 parts by weight of a blueing tarnish, 30 to 60 parts by weight of a carbonating aid and 35 to 55 parts by weight of a brightening agent, It is preferable to form a silver plating layer on the metal contact terminal by using the liquid.

If the amount of the silver chelating agent in the silver plating solution is less than 100 parts by weight based on 100 parts by weight of silver, silver may not completely dissolve and the surface of the silver plating layer may appear cloudy. When the silver plating layer is used in excess of 200 parts by weight, There may be a problem that a rough surface appears. If the amount of the silver plating solution is less than 25 parts by weight based on 100 parts by weight of the silver plating solution, the surface of the silver plating layer may be rough. If the silver plating layer is used in excess of 70 parts by weight, There may be a problem that the phenomenon occurs. Therefore, it is preferable to use within the above range.

The brightener serves to improve the luster of the silver plating layer, and may be a general brightener used in the art. Preferably, the brightener is used in an amount of 5 to 20 parts by weight with respect to 100 parts by weight of the cellulose compound, A brightener containing 1 to 10 parts by weight of a surfactant may be used. More preferably, a brightener containing 10 to 20 parts by weight of a stannate and 1 to 5 parts by weight of a surfactant, based on 100 parts by weight of the cellulose, One); And 5 to 8 parts by weight of a surfactant, based on 100 parts by weight of a celmentium compound, can be mixed and used.

When two kinds of brighteners are used in combination, it is preferable to mix the brighteners 1 and 2 in a weight ratio of 1: 0.1 to 0.3. At this time, when the polishing agent 2 is less than 0.1 weight ratio, gloss of the low current portion may be lowered, and the gloss may be lowered. When the polishing agent 2 is used in a ratio of more than 0.3, the surface of the product may have spots, oil film may be formed, and unevenness may occur.

If the amount of the brightening agent is less than 30 parts by weight based on 100 parts by weight of the cyanating agent, the glossy effect to be obtained may be insufficient. If the brightening agent is used in an amount exceeding 60 parts by weight, It is recommended to use it within the range because it may cause stains.

The washing of the metal bonding terminal with the silver plating layer may be carried out by a general method used in the industry 2 to 4 times, preferably 3 to 4 times.

The drying in step 6 may be performed by a conventional drying method used in the art, preferably by hot air drying or at room temperature (10 ° C to 35 ° C).

Next, the step of forming the silver-plated carbon coating layer in the method for forming the silver-plated carbon coating layer of the present invention will be described in detail. Can be coated with a silver-plated carbon coating solution to form a silver-plated coating layer.

At this time, the characteristics such as the composition, the composition ratio and the pH of the silver-plated coating liquid are the same as those described above. If the temperature of the carbon coating liquid is less than 25 캜, there may be a problem that the coating formability is poor. In addition, If it exceeds 50 캜, there may be a problem that the surface of the silver plating layer or the surface of the discoloration preventing layer formed on the silver plating layer may be denatured. Therefore, it is preferable to coat the silver plating solution with the silver plating coating solution having the temperature within the above range. The method for coating the silver-plated carbon coating solution may be a general method used in the art.

The average thickness of the carbon coating layer is preferably in the range of 3 to 10 μm, preferably in the range of 4 to 8 μm. If the average thickness of the carbon coating layer is less than 3 μm, sufficient abrasion resistance is secured If the average thickness of the carbon coating layer exceeds 10 μm, the conductivity may be lowered and the productivity may be lowered in terms of cost. Therefore, it is preferable to form the carbon coating layer so as to have an average thickness within the above range.

In addition, as described above, in order to improve the long-term discoloration stability of the metal contact terminal, the carbon coating layer may be formed on the surface of the carbon coating layer to form a discoloration preventing layer. The discoloration preventing solution may contain 12 to 125 parts by weight of dichromic acid and 25 to 100 parts by weight of caustic soda, based on 100 parts by weight of carbonic acid. Preferably, the discoloration preventing solution is at least one selected from the group consisting of bichromic acid 30 to 90 parts by weight of glycerol and 40 to 60 parts by weight of caustic soda. If the amount of the dichromic acid is less than 12 parts by weight, there is a problem that there is little discoloration prevention effect. If the amount exceeds 125 parts by weight, there is a problem that the color of the surface of the product appears black. If the amount of the caustic soda is less than 25 parts by weight, there may be a problem that the discoloration prevention layer is not easily formed on the surface of the product. If the amount exceeds 100 parts by weight, the coating on the surface of the product may be peeled off. It is good to do. When the temperature of the discoloration preventing solution is less than 5 ° C, the time for forming the discoloration preventing layer becomes too long, and the productivity may be lowered. If the temperature exceeds 20 ° C, there may be a problem that the discoloration preventing solution is not formed uniformly.

The metal contact terminal of the present invention, which is manufactured through the carbon coating liquid and the carbon coating layer forming method of the present invention described above, Silver plated layer; And a silver-plated coating layer; and a silver plating layer on the surface of the metal contact terminal; A carbon-plated coating layer; And a discoloration preventing layer are stacked in this order, or a silver plating layer is formed on the surface of the metal contact terminal; A discoloration prevention layer; A carbon-plated coating layer; And a discoloration prevention layer may be stacked in this order.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples should not be construed as limiting the scope of the present invention, and should be construed to facilitate understanding of the present invention.

[ Example ]

Preparation Example  One : Silver plating layer  Fabrication of formed metal contact terminals

(1) Preparation of pre-treated metal contact terminals

Contact terminals (fixed terminals and movable terminals) of copper (cu) material schematically shown in Figs. 1A and 1B were prepared, degreased with a degreasing solution, and then washed three times. At this time, the degreasing solution was prepared by mixing 3 parts by weight of sodium cyanide and 3.5 parts by weight of caustic soda (98% concentration) with respect to 100 parts by weight of a degreasing agent (product of Company D of D-50).

Next, the washed contact terminals were acid-treated at 35 캜 for 20 minutes in acidic solution, and then washed three times. At this time, the acid solution was prepared by mixing 55 ml / L of nitric acid (concentration 68%), sulfuric acid (concentration 35%) and 8 ml / L of hydrochloric acid (concentration 35%).

Next, acid-treated and water-contacted contact terminals were placed in the copper plating solution, copper plating was carried out at 50 캜 under a current density of 1.2 to 1.3 mA / dm ² , and three times of washing were performed. At this time, 75 parts by weight of the bluing agent 1, 50 parts by weight of caustic soda, 35 parts by weight of rochelle salt, and 18 parts by weight of rosorbite were mixed with 100 parts by weight of cyanide soda.

Next, the copper-plated and washed contact terminals were immersed in an Ag striking liquid mixed at 3.5 g / L of chlorination at 25 ° C., 18 g / L of blue tarnish (H Company), 90 g / L of carbon black (H Company) After the Ag strike treatment, the metal contact terminal was pretreated by washing with water three times.

 (2) Silver-plated  formation

A silver plating solution was prepared by mixing and stirring 35 g / L of blue color, 50 g / L of blue tar, 15 g / L of carbon dioxide and 40 g / L of brightener. At this time, the brightener was prepared by mixing LSP 100 (product H) and LSP 200 (product H) at a weight ratio of 1: 0.2.

After the pre-treated metal contact terminals were put in the silver plating solution, plating was performed at a contact pressure of 1.5V to 1.6V to form and wash a silver plating layer having an average thickness of 7.5 mu m to manufacture a metal contact terminal having a silver plating layer Respectively. At this time, when the plating process was carried out, the temperature of the silver plating solution was 35 占 폚.

Preparation Example  2 : Silver plating layer  Fabrication of formed metal contact terminals

A metal contact terminal having a silver plating layer formed thereon was prepared in the same manner as in Preparation Example 1.

Next, on the surface of the silver plated layer of the metal contact terminal having the silver plating layer formed thereon, a color fading inhibitor (trade name: DL-3005, manufactured by DAE Co., Ltd.) containing 75 parts by weight of dichromic acid and 48 parts by weight of caustic soda, Metal) was coated thereon to form a discoloration preventing layer to prepare a metal contact terminal in which a copper plating layer, a silver plating layer, and a discoloring prevention layer were sequentially laminated on the surface of the metal contact terminal.

Example  One

(One) Carbon plating  Preparation of coating liquid

150 parts by weight of blue phosphorus, 34 parts by weight of carbon dioxide, 430 parts by weight of graphite powder having an average particle diameter of 1 탆 to 1.5 탆, 35 parts by weight of a tetramethylammonium cationic surfactant and 45 parts by weight of a dispersing and stirring agent And the mixture was sufficiently stirred for 1 hour to prepare a silver-carbon coating solution having a pH of 12.5.

The dispersing and stirring agent used herein was a mixture of polyoxyethylenelauryl ether, ethylene glycol monobutyl ether and ethylene glycol at a weight ratio of 1: 0.7: 1.5.

(2) Carbon plating  Formation of coating layer

A portion of the metal contact terminal formed with the silver plating layer prepared in Preparation Example 1 was immersed in the silver-plated carbon coating liquid (40 ° C), and then taken out and sufficiently washed with water for about five times to remove the electrodeposited graphite powder, A metal contact terminal having a silver carbon-plated coating layer (average thickness of 6 mu m) formed on the surface of the silver-plated layer was prepared.

(3) Discoloration prevention layer  formation

remind The copper plating - silver plating layer-product was a product which contained 60 parts by weight of dichromic acid and 50 parts by weight of caustic soda (DL-3000, manufactured by Daelim Co., Ltd.) as a discoloring inhibitor on the surface of the metal contact terminal where the carbon- (Average thickness: 6 占 퐉) and a discoloration prevention layer were successively laminated on the surface of the metal contact terminal, thereby forming a metal contact Terminal.

Example  2

(Average thickness: 7.5 mu m) - carbon coating layer (average thickness: 6 mu m) - discoloration (thickness: 5 mu m) was formed using the silver carbon coating solution having the following composition instead of the silver carbon coating solution of Example 1, Barrier layer were sequentially stacked on the metal contact terminal.

The carbon-plated coating solution of Example 2 was prepared by blending 120 parts by weight of blue tarnish, 55 parts by weight of carbon black, 450 parts by weight of graphite powder having an average particle size of 3 mu m to 3.5 mu m, a tetramethylammonium cation surfactant 40 And 50 parts by weight of a dispersion stirrer were sufficiently mixed and stirred for 1 hour to prepare a silver-carbon coating solution having a pH of 12.5.

The dispersing and stirring agent used herein was a mixture of polyoxyethylenelauryl ether, ethylene glycol monobutyl ether and ethylene glycol at a weight ratio of 1: 0.7: 1.5.

Example  3 ~ Example  4

A silver-plated coating solution was prepared in the same manner as in Example 1, except that a silver-plated layer (average thickness of 7.5 mu m) -carbon coating layer (average thickness of 6 mu m) Were used in Examples 3 and 4, respectively.

Example  5 ~ Example  6

A metal contact terminal in which a silver plating layer (average thickness of 7.5 mu m) - carbon coating layer (average thickness of 6 mu m) and a discoloring prevention layer were laminated in this order was manufactured using the same method as in Example 1, Example 5 was carried out using a dispersion agitator containing polyoxyethylenelauryl ether, ethylene glycol monobutyl ether and ethylene glycol as a stirring agent at a weight ratio of 1: 0.5: 1.6.

Example 6 was carried out using a dispersion agitator comprising polyoxyethylenelauryl ether, ethylene glycol monobutyl ether and ethylene glycol in a weight ratio of 1: 0.7: 1.

Example  7 ~ Example  8

A metal contact terminal in which a silver plating layer (average thickness of 7.5 mu m) - carbon coating layer (average thickness of 6 mu m) and a discoloring prevention layer were laminated in this order was prepared in the same manner as in Example 1, and the pH of the silver carbon coating solution was adjusted to 11.2 Example 7 was carried out.

In Example 8, the silver carbon coating solution was adjusted to pH 14.3.

Example  9

The silver contact layer of the preparation example 2 instead of the metal contact terminal having the silver plating layer prepared in Preparation Example 1 was produced in the same manner as in Example 1 except that the silver contact layer having a silver- Using the metal contact terminals, a metal contact terminal having a silver plated layer (average thickness of 7.0 mu m) - a discoloration preventing layer - a carbon-plated coating layer (average thickness: 8.5 mu m)

division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Cheonghwa 100 100 100 100 100 100 100 100 100 Cheonghapgari 150 120 200 150 150 150 150 150 150 Carbonate 34 55 35 30 34 34 34 34 34 Graphite powder 430 450 430 400 430 430 430 430 430 Surfactants 35 40 40 35 35 35 35 35 35 Dispersion agitator 45 50 45 60 45 45 45 45 45 pH 12.5 12.4 12.5 12.7 12.4 12.5 11.1 14.3 12.5

Comparative Example  One

A metal contact terminal in which a silver plating layer (average thickness of 7.0 mu m) - a discoloration preventing layer was laminated was prepared in the same manner as in Example 1 except that a silver carbon coating layer was not formed.

Comparative Example  2

A metal contact terminal having a silver plating layer (average thickness of 7.5 mu m) - carbon coating layer (average thickness of 6 mu m) - a discoloration preventing layer was produced in the same manner as in Example 1, and Comparative Example 2 was produced in the same manner as in Example 1 except that graphite powder having an average thickness of 2.5 to 3 [ Was used to fabricate a metal contact terminal.

Comparative Example  3

In the same manner as in Example 1, A metal contact terminal having a silver plating layer (average thickness of 7.5 mu m) - silver carbon coating layer (average thickness of 6 mu m) - discoloration preventing layer was prepared, and a carbon coating solution of pH 9 was used in Comparative Example 2.

Comparative Example  4 ~ Comparative Example  9

In the same manner as in Example 1, A carbon-plated coating layer (average thickness of 7.5 mu m) - silver carbon-coated coating layer (average thickness of 6 mu m) - A carbon-coated coating solution prepared to have the composition ratio shown in Table 2, To Comparative Example 9 were carried out.

division Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Cheonghwa 100 100 100 100 100 100 100 100 Cheonghapgari 150 150 70 150 150 150 150 150 Carbonate 34 34 34 10 34 34 34 34 Graphite powder 430 430 430 430 250 430 430 430 Surfactants 35 35 35 35 35 10 35 35 Dispersion agitator 45 45 45 45 45 45 4 120 pH 12.3 9 12.5 12.5 12.4 12.5 12.5 12.6

Comparative Example  10 ~ Comparative Example  11

A metal contact terminal having a silver plating layer (average thickness of 7.5 mu m) -carbon coating layer (average thickness of 6 mu m) -decolorization preventing layer formed thereon was prepared in the same manner as in Example 1, except that, as the dispersion agitator, polyoxyl ethylene lauryl ether, ethylene Comparative Example 10 was carried out using a dispersion stirrer containing glycol monobutyl ether and ethylene glycol at a weight ratio of 1: 0.3: 1.5.

Comparative Example 11 was carried out using a dispersing and stirring agent comprising polyoxyethylenelauryl ether, ethylene glycol monobutyl ether and ethylene glycol as a dispersion agent at a weight ratio of 1: 0.7: 2.5.

Experimental Example  1: Measurement of physical properties of metal contact terminals

The durability, lubricity, conductivity, and discoloration resistance of the metal contact terminals prepared in the above Examples and Comparative Examples were measured and the results are shown in Table 3 below. Each measuring method is shown below.

(1) Method of measuring corrosion resistance

The metal contact terminals prepared in Examples and Comparative Examples were measured and submitted to the Korea Chemical Fusion Test Institute. The neutral salt spray test was carried out in accordance with KS D 9502: 2009. The results of the neutral salt spray test were based on the discoloration and the occurrence of bluish green after 48 hours.

The test result of the metal contact terminal manufactured in Example 1 is shown in Figs. 2A and 2B.

(2) Method of measuring abrasion resistance

The abrasion resistance of the carbon-plated coating layers of Examples and Comparative Examples was measured, and the results are shown in Table 3 below. The abrasion resistance test was based on KS D 8335: 2001. Specifically, the abrasion resistance test was carried out using a CC-800 abrasive paper as a table-type abrasion method, and the degree of abrasion was tested without using a lubricant at a load of 5N. At this time, the number of times when the coating layer was peeled off, that is, when the wear occurred, is shown in Table 3.

 (3) Conductivity  How to measure

After a voltage of 220 V was applied to the metal contact terminals prepared in Examples and Comparative Examples, the electric current difference between the portions where the silver-plated coating layer was formed and the portions where the silver-plated coating layer was not formed were measured using a circuit tester, Respectively. The electrical conductivity was measured based on 100% of the measurement value of the metal contact terminal (stationary terminal) in which the silver-carbon coating layer of Comparative Example 1 was not formed.

As a result of the measurement of the above Table 1, the corrosion resistance, abrasion resistance and electric conductivity of the examples 1 to 9 were excellent. However, in the case of Comparative Example 2 using 2.5 to 3 탆 graphite powder, there was a problem that conductivity was greatly reduced. In the case of the silver-plated coating layer of Comparative Example 3 having a pH of less than 10, Comparative Example 5 using less than 25 parts by weight of carbonic acid and Comparative Example 7 using less than 25 parts by weight of the surfactant, There was a problem in that it was not uniformly and neatly formed. However, this had some influence on the conductivity, so that the electrical conductivity was relatively lowered compared with the examples, and a part was discolored. Also, in the case of Comparative Example 4 in which the bluish purple color was used in an amount of less than 100 parts by weight, the coating film of the silver-plated carbon coating was cloudy, and the electric conductivity was somewhat lowered as compared with Example 1. In the case of Comparative Example 6 in which the graphite powder was used in an amount of less than 300 parts by weight, there was a problem that the abrasion resistance was poor. In addition, in the case of Comparative Example 8 using less than 10 parts by weight of the dispersing agitator, the abrasion resistance and electric conductivity were poor. This is because the graphite powder was not uniformly dispersed in the silver-plated coating layer. In the case of Comparative Example 9 in which the dispersing and stirring agent was used in an amount exceeding 100 parts by weight, the abrasion resistance was deteriorated as compared with the Examples.

Further, in the case of Comparative Example 10 prepared from a silver-carbon coating liquid containing a dispersing and stirring agent containing less ethylene glycol monobutyl ether, the dispersibility of the graphite powder was somewhat lowered, and the abrasion resistance and electrical conductivity were somewhat lower Results. In Comparative Example 11 prepared from a silver carbon coating solution containing a dispersing and stirring agent in which ethylene glycol was used in a large amount, the abrasion resistance was relatively lower than that in Example 1.

Through the above Examples and Experimental Examples, it was confirmed that the metal contact terminal formed with the silver carbon coating layer by using the silver carbon coating liquid having the method and composition shown by the present invention not only has excellent conductivity, but also has excellent corrosion resistance and wear resistance there was.

Claims (22)

Cheonghwa Eun; Cheonghwagari; Carbonic acid; Graphite powder having an average particle diameter of 0.5 to 2 占 퐉; A dispersion agitator comprising polyoxyethylenelauryl ether, ethylene glycol monobutyl ether and ethylene glycol in a weight ratio of 1: 0.5 to 1: 1 to 2; And a surfactant,
Wherein the blend comprises 100 to 200 parts by weight of blue phosphorus, 25 to 70 parts by weight of the carbon black, 300 to 550 parts by weight of the graphite powder, 10 to 100 parts by weight of the dispersion stirrer and 25 to 70 By weight based on the total weight of the coating liquid. delete The method according to claim 1, wherein the surfactant is at least one selected from the group consisting of alkyltrimethylammonium compounds, dialkyldimethylammonium compounds, trialkylmethylammonium compounds, tetraalkylammonium compounds, polydiaminodimethylammonium compounds, A silver plating coating characterized by comprising a cationic surfactant containing at least one selected from the group consisting of a polyimide compound, a polyimide compound, a polyacrylamide compound, a polyethyleneimine diammonium compound, a benzyl compound, a pyridinium compound and a polyvinyl pyridine compound Coating solution for carbon plating. delete The silver plating coating solution for silver plating according to claim 1 or 3, wherein the pH is 10-15. Preparing a metal contact terminal having a silver plating layer formed thereon; And
And coating the surface of the silver plated layer with the silver carbon coating liquid of claim 5 to form a silver plated carbon coating layer. The method according to claim 6, wherein the temperature of the silver-plated coating liquid is 20 ° C to 30 ° C. The method as claimed in claim 6, wherein the step of preparing the metal contact terminal having the silver plating layer is formed by plating a metal contact terminal with a silver plating solution,
Wherein the silver plating solution comprises 100 to 200 parts by weight of blue phosphorus, 25 to 70 parts by weight of carbon black, and 30 to 60 parts by weight of a brightener, based on 100 parts by weight of silver chloride. The method of claim 8, wherein the brightener comprises 5 to 20 parts by weight of stannate and 1 to 10 parts by weight of a surfactant based on 100 parts by weight of the cellulose. 10. The method of claim 9,
A selinium-based brightener comprising 10 to 20 parts by weight of a tartrate and 1 to 5 parts by weight of a surfactant based on 100 parts by weight of the cellulose composition; And
5 to 10 parts by weight of a tartrate and 5 to 8 parts by weight of a surfactant based on 100 parts by weight of a celinium compound;
In a weight ratio of 1: 0.1 to 0.3. The method as claimed in claim 8, wherein the metal contact terminal
A first step of degreasing the metal contact terminal; Washing the degreased metal contact terminal with water; A third step of acid washing and washing the washed metal contact terminals; A fourth step of copper-plating the re-washed metal contact terminals; 5 steps of washing the copper-plated metal contact terminals with water, Ag strike treatment, and then re-aging; Forming a silver plating layer on the surface of the re-aged metal contact terminal by plating with the silver plating solution, and washing and drying the silver plating layer. Lt; / RTI > 12. The method according to claim 11, wherein the step (6)
And forming a discoloration preventing layer by coating the surface of the silver plating layer of the metal bonding terminal having the silver plating layer with a discoloration preventing solution. The method according to claim 11, wherein the degreasing in the first step is performed by degreasing the metal contact terminal with a degreasing solution containing 2 to 5 parts by weight of sodium chloride and 2 to 5 parts by weight of caustic soda with respect to 100 parts by weight of the degreasing agent Lt; / RTI > coating a carbon-plated coating layer. 12. The method according to claim 11,
Characterized in that the method is carried out with an acidic solution comprising 35 to 59% by volume of nitric acid, 40 to 60% by volume of sulfuric acid and 0.5 to 15% by volume of hydrochloric acid at 30 占 폚 to 40 占 폚. 12. The method of claim 11, wherein the copper plating in step
Copper plating was carried out at a copper amount of 40 ° C to 60 ° C and a pH of 12.0 to 13 and at a current density of 1 to 1.5 mA / dm ² ,
The copper plating solution contains 50-100 parts by weight of a bluing agent 1, 40-60 parts by weight of caustic soda, 20-50 parts by weight of rochelle salt and 10-25 parts by weight of rosiglitazone per 100 parts by weight of cyanide soda ≪ / RTI > wherein the silver-plated coating layer is coated with a silver-plated coating layer. 12. The method according to claim 11, wherein the Ag strike in the step
Treated with an Ag strike liquid at 20 ° C to 35 ° C,
Wherein the Ag strike solution contains 2 to 5 g / L of cyanide, 80 to 100 g / L of blue tar, and 10 to 25 g / L of carbonic acid. The method according to claim 6, further comprising the step of coating the surface of the silver-plated carbon coating layer with a discoloration preventing solution to form a discoloration preventing layer at a temperature of 5 ° C to 20 ° C to coat the carbon- . [18] The method of claim 17, wherein the discoloration preventing solution comprises 12 to 125 parts by weight of dichromic acid and 25 to 100 parts by weight of caustic soda with respect to 100 parts by weight of carbonic acid. On the surface of metal contact terminals
Copper plating; Silver plated layer; And a silver-carbon-plated coating layer coated with the carbon-plating coating solution of claim 5 are laminated in this order. The metal contact terminal according to claim 19, wherein a discoloration preventing layer is further laminated on the surface of the silver-plated coating layer. The metal contact terminal according to claim 19, further comprising a discoloration preventing layer between the silver plating layer and the silver carbon coating layer. The metal contact terminal according to claim 19, wherein the silver-plated coating layer has an average thickness of 3 to 10 mu m.

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