KR102531345B1 - Silver carbon plating agent having excellent discoloration resistance, abrasion resistance, heat resistance, electro-conductive property and lubricant property and Plating method using the same - Google Patents

Abstract

The present invention relates to a silver-carbon plating solution used for plating to improve the corrosion resistance and discoloration resistance of parts made of copper (Cu) and/or copper alloy with a silver (Ag) plating layer formed thereon, and a method for manufacturing the same. The silver-carbon plating solution contains 30 to 45 g/L of KAg(CN)_2, 80 to 135 g/L of KCN, 5 to 40 g/L of K_2CO_3, 2 to 15 g/L of KOH, 2 to 8 mg/L of metal brightener, 1 to 7 ml/L of nonionic surfactant, 50 to 200 g/L of dispersed graphite suspension, and water as solvent.

Description

Silver carbon plating agent having excellent discoloration resistance, abrasion resistance, heat resistance, electro-conductive property and lubricant property and Plating method using the same same}

The present invention is a composite plating method (COMPOSITE PLATING METHOD) in which inert particles are deposited from a plating electrolyte. In order to prevent oxidation of copper or copper alloy as a material for conventional sliding contact parts such as switch contacts or connectors, silver plating was used. A method of forming a silver carbon plating film with excellent heat resistance, wear resistance, lubrication, and discoloration resistance by dispersing carbon particles in an Ag matrix to improve the problem of easy wear due to sliding because the film is soft and has low wear resistance and high friction coefficient. am.

A sliding contact is used between a moving part and a fixed part in an electric device having a mechanically operated conductive part, such as a circuit breaker, disconnection contactor, load switch or connect.

In addition, the sliding contact is made of copper and/or copper alloy, but has a short lifespan due to oxidation. In order to prevent this oxidation phenomenon, the sliding contact with low current resistance and no oxidation phenomenon was plated, and silver plating was usually used for plating.

In the conventional silver plating method, a composition containing a cyanide compound was usually used, but the cyanide compound has a fatal effect on the human body, and its use has been gradually reduced in recent years. is being proposed The cyanide compounds include metal salts of HCN, such as KCN and NaCN, and complex cyanates such as potassium ferrocyanide and potassium ferrocyanide. In addition, the metal salt of HCN easily liberates cyan ions in water and is highly toxic and causes severe poisoning, resulting in a very high mortality rate. Cyan complex salts are formed of metal complexes, and there are complex salts such as zinc or cadmium, which are relatively easy to dissociate, whereas complex salts such as copper, cobalt, and iron are very stable and have very low toxicity. When KCN or NaCN, a cyanide compound, enters the body through the oral route, HCN is released by gastric acid, which is absorbed in the body and combines with iron, a component of cytochrome oxidase, to form a safe complexing agent, It becomes hemoglobin, and by the above, the enzyme transport function of hemoglobin is inhibited, and oxygen cannot be supplied to the living body, resulting in asphyxiation. In addition, symptoms of poisoning include dizziness, headache, loss of consciousness, and convulsions, and in the case of high concentrations, respiratory arrest due to paralysis of the respiratory center causes death.

Accordingly, an environmentally friendly silver plating method that does not use cyanide is developed and applied. For example, in Korean Publication No. 10-2006-0127340, silver sulfate, ammonium sulfate, citric acid, ferrous sulfate, ammonia water, particle carbon , Ruthenium, Teflon, and PTFE using a plating solution to form a copper or copper alloy contact terminal silver plating technology has been disclosed, the silver plating solution of this composition is environmentally friendly in that it does not use a cyanide compound, but, There is a problem such as an excessively high manufacturing cost of the plating solution.

Republic of Korea Publication No. 10-2006-0127340 (Announcement date 2006.12.12.)

The present inventors have found that when graphite powder, which is a carbon powder used in a silver carbon plating solution, is introduced into a graphite suspension subjected to dispersion treatment, hydrophobic organic substances on the surface of the graphite powder are removed, and the graphite powder having a high surface resistance improves the homogeneity and dispersibility of the graphite powder in the plating solution. , it was found that a silver carbon plating layer having excellent corrosion resistance and discoloration resistance could be formed by forming a silver carbon plating layer in which the carbon component was uniformly distributed, and the present invention was completed. That is, the present invention is to provide a silver carbon plating solution and a silver carbon plating treatment method using the same.

The present invention for solving the above problems relates to a silver carbon plating solution, and includes KAg(CN) ₂ , KCN, K ₂ CO ₃ , KOH, a metal polishing agent, a nonionic surfactant, a dispersion-treated graphite suspension, and a solvent.

In addition, the present invention relates to a plating treatment method using a silver carbon plating solution, comprising the steps of preparing a copper-based or copper-alloy-based component having a silver (Ag) plating layer formed thereon; and a second step of forming a silver carbon (Ag-C) plating layer by plating the surface of the silver plating layer with the silver carbon plating solution of any one of claims 1 to 7.

The silver carbon plating layer plated with the silver carbon plating solution of the present invention has excellent corrosion resistance and discoloration resistance as the carbon component (C) is uniformly distributed in the plating layer, as well as excellent heat resistance, wear resistance and electrical properties.

1 is an EDS measurement image of Examples 1 to 3 and Comparative Examples 1 to 3 conducted in Experimental Example 1.
Figure 2 is a photograph taken after measuring the discoloration resistance of Examples 1 to 3 and Comparative Examples 1 to 3 conducted in Experimental Example 2.
3 is a photograph taken after measuring the heat resistance of Examples 1 to 3 and Comparative Examples 1 to 3 conducted in Experimental Example 2.

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

The silver carbon plating solution of the present invention includes KAg(CN) ₂ , KCN, K ₂ CO ₃ , KOH, a metal polishing agent, a nonionic surfactant, a graphite suspension subjected to dispersion treatment, and a solvent.

KAg(CN) ₂ serves to increase the silver concentration as a main source of silver (Ag) ions forming a silver carbon plating layer, and KCN dissolves KAg(CN) ₂ well in a solvent and serves to dissolve the anode do

The appropriate concentration of KAg(CN) ₂ in the silver carbon plating solution is 20 to 50 g/L, preferably 30 to 45 g/L, and more preferably 35 to 43 g/L. At this time, the concentration of KAg(CN) ₂ in the plating solution If the concentration is less than 20g/L, the bonding strength between the silver plating layer and the silver carbon plating layer may be poor, resulting in poor corrosion resistance and wear resistance. . In addition, the appropriate concentration of KCN in the silver carbon plating solution is 80 to 150 g/L, preferably 80 to 135 g/L, and more preferably 90 to 120 g/L. At this time, when the KCN concentration is less than 80 g/L, KAg (CN ) ₂ may have insufficient solubility in the solvent, decrease in carbon vacancy rate, and continuous decrease in Ag concentration. There may be a problem in which is continuously increasing.

Among the components of the silver carbon plating solution, the K ₂ CO ₃ serves to improve surface uniformity and electrical conductivity of the silver carbon plating layer, and the appropriate concentration of K ₂ CO ₃ in the silver carbon plating solution is 1 to 50 g/L, preferably is 5 to 40 g/L, more preferably 8 to 20 g/L. At this time, if the K ₂ CO ₃ concentration of the silver carbon plating solution is less than 1 g/L, the amount used is too small and _the effect _of improving the surface uniformity of the plating layer may be insignificant. It is good to use it within the above range because there may be a problem that is not formed.

In addition, the KOH among the components of the silver carbon plating solution serves to adjust the pH, and the appropriate concentration of KOH in the silver carbon plating solution is 1 to 20 g/L, preferably 2 to 15 g/L, and more preferably 3 to 10 g/L. is L. At this time, if the KOH concentration in the silver carbon plating solution is less than 1 g / L, the amount used is too small, and the effect of correcting the pH may be insufficient. Therefore, it is recommended to use it within the above range.

In addition, among the components of the silver carbon plating solution, the metal brightener serves to increase the gloss of the silver carbon plating layer and increase the hardness of the plating film, and includes at least one selected from KSeCN, Na ₂ Se, and Na ₂ SeO ₄ Se-based compound; K ₂ Sb ₂ C ₈ H ₄ O _12, O ₁₂ S ₃ Sb ₂ (Antimony sulfate), Sb ₂ O ₃ , Sb ₂ S ₅ Sb-based compound containing at least one selected from; Bi ₂ O ₃ , BiCl ₂ , Bi-based compound containing at least one selected from NaBiO ₃ ; One or more selected from among may be used. In addition, the proper concentration of the metal polishing agent in the plating solution is 0.5 to 50mg/L, preferably 1 to 20mg/L, and more preferably 1 to 10mg/L. At this time, if the concentration of the metal polishing agent is less than 1mg/L, the usage amount If it is too small, the surface of the silver carbon plating layer is rough and the leveling effect is insufficient, and if it is used in excess of 10 mg/L, there may be a problem of reducing carbon vacancies, so it is good to use it within the above range.

In addition, the nonionic surfactant among the components of the silver carbon plating solution acts as a hydrophilic agent to form an even coating layer by reducing the surface tension of the silver carbon plating solution, and polysorbate, octyldodeches and polyoxyethylene It is good to use at least one selected from among alkyl ethers, preferably polysorbate. In addition, the appropriate concentration of the nonionic surfactant in the plating solution is 1 to 10 ml / L, preferably 1.0 to 7.0 ml / L, more preferably 1.5 to 4.5 ml / L, and at this time, the nonionic surfactant concentration is 1 ml If it is less than /L, the surface of the silver carbon plating layer may be formed rough because the amount is too small, and if it is used in excess of 10 ml / L, the bonding strength with the silver plating layer is deteriorated, and the corrosion resistance and wear resistance of the silver carbon plating layer may deteriorate. Therefore, it is recommended to use it within the above range.

In addition, the graphite suspension dispersed among the components of the silver carbon plating solution is an oxidizing agent containing at least one selected from sulfuric acid, nitric acid, hydrogen peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, potassium permanganate and potassium periodate, Graphite powder whose surface is oxidized to remove hydrophobic organic materials; and a dispersion wetting agent.

The dispersion wetting agent may include at least one selected from glycol ethers and lauryl alcohol ethoxylate, preferably lauryl alcohol ethoxylate and ethylene glycol monoethyl ether. ), and one to three selected from acetic acid salts of ethylene glycol monoethyl ether and ethylene glycol monobutyl ether.

In the dispersion-treated graphite suspension manufacturing process, first, oxidation treatment is performed to remove hydrophobic organic substances present on the surface of the graphite powder, and graphite powder of carbon material having a large surface resistance that improves homogeneity and dispersibility by oxidation treatment This is uniformly suspended and dispersed in the plating solution, so that a plating layer having a uniform carbon distribution rate in the silver carbon plating can be formed.

As a preferred embodiment of a method for preparing a dispersion-treated graphite suspension, 200 g of graphite powder and 1 L of pure water are added to a beaker, heated to 50 ° C, and stirred at 100 rpm using an impeller agitator for 2 hours. In a separate container, 0.2 ~ 0.5M of persulfate is dissolved in 500ml of pure water while heating to 50℃. After 2 hours of stirring, a persulfate solution dissolved in the graphite solution was slowly added. After addition, the mixture is stirred at 100 to 120 rpm using an impeller stirrer for 5 hours. When stirring is completed, the graphite solution is filtered. When filtering, wash with pure water until the filtered water has a pH of 7. To the filtered graphite powder, 200 g of pure water and 8 to 12 g of lauryl alcohol ethoxylate and 8 to 10 g of ethylene glycol monoethyl ether were added as nonionic surfactants, and stirred for 2 hours at 50 rpm using an impeller stirrer to obtain a dispersion treatment. A graphite suspension can be prepared.

The graphite powder having a particle size of 1 to 10 μm, preferably a particle size of 1 to 7 μm, and more preferably a particle size of 2 to 5 μm is used as a material for the plating solution of the present invention. At this time, the oxidized graphite powder If the particle diameter is less than 1㎛, there may be a problem that the electrical resistivity of the silver carbon plating layer increases and the lubricity decreases. Since there may be, it is preferable to use one having a particle diameter in the above range.

In addition, the appropriate concentration of the graphite suspension dispersed in the plating solution is 50 to 200 g/L, preferably 100 to 180 g/L, and more preferably 140 to 160 g/L. At this time, the concentration If it is less than 50 g/L, the amount used is too small and there may be a problem of reducing carbon vacancies, and if it is used in excess of 200 g/L, it is excessive use, and the bath voltage decreases the plating rate and increases the bath voltage. There may be, so it is good to use it within the above range.

The plating layer plated with the silver carbon plating solution of the present invention described above may have a carbon vacancy amount of 1 to 10%, preferably 3 to 10%, more preferably, when analyzed by EDS mapping (Energy dispersive X-ray spectrometry mapping). It may be 7-9%.

A method of forming the silver carbon plating layer on a body to be plated on which the silver plating layer is formed using the silver carbon plating solution of the present invention described above will be described.

A method of forming a silver carbon plating layer of the present invention includes preparing a body to be plated on which a silver plating layer is formed; and forming a silver carbon plating layer by coating the surface of the silver plating layer with the silver carbon plating solution in various forms described above, and further forming an anti-discoloration layer by coating the surface of the silver carbon plating layer with an anti-discoloration liquid. It may further include;

First, the step of preparing a body to be plated on which a silver-plated layer is formed will be described in detail.

The object to be plated may be an electrical or electronic component including metals such as copper (Cu) and its alloys, iron (Fe), aluminum (Al), and stainless steel, or alloy components thereof.

Then, a first step of degreasing the object to be plated on which the silver plating layer is formed; A second step of washing the degreased object to be plated with water; a third step of washing the washed object to be plated with water again after acid treatment; 4th step of copper-plating the again-washed object to be plated; Step 5 of washing the copper-plated object to be plated with water, then Ag strike treatment, and then washing again with water; It can be manufactured by performing a process including: forming a silver plating layer by plating the surface of the object to be plated with the silver plating solution washed again in step 5, then washing with water and drying.

The first step of degreasing is to remove oil or other foreign substances on the surface of the metal contact terminal, and can be performed by degreasing the plated body with a degreasing agent, a degreasing solution containing NaCN and NaOH. At this time, as the degreasing agent, a general degreasing agent used in the art may be used. And, after performing the degreasing, water washing may be performed 2 to 4 times, preferably 3 to 4 times by a general method used in the art.

The acid treatment in the third step is to oxidize and remove the metal surface of the metal contact terminal by acid treating the plated body degreased with an acid solution for 5 to 20 minutes at 20 to 40 ° C. This is to improve adhesion. In particular, when the object to be plated is non-ferrous (copper, brass, phosphor bronze, etc.), the acidic solution used for the acid treatment is preferably one containing 10 to 30 vol% of sulfuric acid or 10 to 30 vol% of hydrochloric acid. In addition, acid treatment at a temperature of 20 to 40 ° C can remove impurities on the surface of the raw material and remove the surface of the material uniformly, cleanly and uniformly. Then, the acid-treated object to be plated is washed with water, and the washing with water can be performed 2 to 4 times, preferably 3 to 4 times, by a general method used in the art.

The copper plating in step 4 may be performed using a copper plating solution at 40 to 60°C and a current density of 1 to 2A/dm ² . At this time, if the temperature is less than 40°C during copper plating, the surface of the raw material is dark and has a dark red color. There may be a problem of coming out, and if the temperature exceeds 60 ° C, a problem may occur that the surface of the product comes out rough while the current flows strongly, so it is good to perform copper plating within the above temperature. In addition, it is preferable that the copper plating solution has a pH of 12.0 to 13.0. At this time, if the pH of the copper plating solution is less than 12.0, there may be a problem in that the thickness of the coating film is deposited on the surface of the product late. Since there may be a problem in that the coating film is formed roughly, it is preferable to have the above pH range.

In addition, the copper plating solution may include NaCN, cuprous cyanide, NaOH, rochelle salt, and potassium thiocyanate.

Then, the copper-plated metal contact terminal is washed with water, and the water washing may be performed 2 to 4 times, preferably 3 to 4 times, by a general method used in the art.

The Ag strike in the 5th step can treat copper-plated objects with Ag strike liquid at room temperature of 20 to 35 ° C, and the Ag strike liquid may contain KAg(CN) ₂ or AgCN, KCN and potassium carbonate. can

In addition, the silver plating solution in step 6 may be a silver plating solution used in the art and a general silver plating method, preferably a silver plating solution containing KAg(CN) ₂ or AgCN, KCN, potassium carbonate, KOH, and a brightener It is preferable to form a silver plating layer on the surface of the object to be plated by using.

In addition, the metal bonding terminal having the silver-plated layer may be washed with water 2 to 4 times, preferably 3 to 4 times, by a general method used in the art.

Next, in the method of forming the silver carbon plating layer of the present invention, the step of forming the silver carbon plating layer will be described in detail. A silver carbon plating layer may be formed by plating with a carbon plating solution.

In this case, the characteristics of the composition and composition ratio of the silver-carbon plating solution are the same as those described above. In addition, during plating, the temperature of the silver carbon plating solution is preferably 18 to 30 ° C, preferably 18 to 25 ° C, more preferably 18 to 23 ° C. At this time, if the temperature of the carbon coating solution is less than 18 ° C, plating There may be a problem of poor moldability, and if the temperature exceeds 30 ° C, there may be a problem of causing denaturation to the surface of the silver plating layer or the surface of the anti-discoloration layer formed on the silver plating layer. A state in which the silver carbon plating solution has a temperature within the above range Plating treatment is good. In addition, as a method of plating the silver carbon plating solution, a general method used in the art may be used.

In addition, the pH of the silver carbon plating solution is preferably 11 to 13, preferably 11.5 to 13.0, and more preferably 12.0 to 13.0. At this time, if the pH of the silver carbon plating solution is less than 11, there may be a problem of deterioration in gloss. In addition, if the pH of the silver carbon plating solution exceeds 13, there may be a problem that the plating film becomes rough.

In addition, the thickness of the silver carbon plating layer is preferably formed to an average thickness of 3 to 12㎛, preferably an average thickness of 6 to 10㎛. At this time, if the average thickness of the silver carbon plating layer is less than 4㎛, sufficient wear resistance and corrosion resistance are secured. If the average thickness of the silver carbon plating layer exceeds 12 μm, there may be a problem in that the current rate is lowered and productivity is lowered in terms of price. Therefore, it is preferable to form the silver carbon plating layer to have an average thickness within the above range.

After plating, post-treatment is performed to enhance corrosion resistance and discoloration resistance. After general plating treatment, post-treatment is performed to enhance corrosion resistance or discoloration resistance. Most industries use organic compounds or hexavalent chromium for post-treatment. -400EP Manufacturer: Youngin Plachem Co., Ltd.) is used to show excellent discoloration resistance.

Hereinafter, the present invention will be described in more detail based on examples. However, the scope of the present invention should not be limited and interpreted by the following examples.

[Example]

Preparation Example 1: Preparation of dispersed graphite suspension

Graphite powder having a particle size of 2.2 to 5.5 μm was prepared.

200 g of graphite powder and 1 L of pure water were added to a beaker, heated to 50° C., and stirred at 100 rpm using an impeller agitator for 2 hours. In a separate container, 0.2 ~ 0.5M of persulfate is dissolved in 500ml of pure water while heating to 50℃.

Next, after 2 hours of stirring, a persulfate solution dissolved in the graphite solution was slowly added.

Next, the mixture was stirred at 100 to 120 rpm using an impeller stirrer for 5 hours after addition. When stirring was completed, the graphite solution was filtered. When filtering, wash with pure water until the filtered water has a pH of 7.

Next, 200 g of pure water and nonionic surfactants, 10 g of lauryl alcohol ethoxylate and 9 g of ethylene glycol monoethyl ether were added to the filtered graphite powder, and stirred for 2 hours at 50 rpm using an impeller stirrer to disperse graphite A suspension was prepared, and the graphite powder in the suspension had a particle diameter of 2.2 to 5.5 μm (average particle diameter of about 3.0 μm).

Example 1: Manufacturing and Plating Treatment of Silver Carbon Plating Layer

(1) Manufacture of silver carbon plating solution

KAg(CN) ₂ 40g/L, KCN 100g/L, K ₂ CO ₃ 10g/L, KOH 5g/L, Se 4mg/L as a metal brightener, polysorbate as a nonionic surfactant, 2ml/L in water as a solvent , 80 g/L of the dispersion-treated graphite suspension prepared in Preparation Example 1 was added to prepare a silver carbon plating solution having a pH of 12.5.

(2) Plating the object to be plated with a silver carbon plating solution

A specimen of brass material having an area of 0.3 dm2 was prepared as an object to be plated.

A plating process was performed on the object to be plated with the silver carbon plating solution (20° C.) having a pH of 12.5 under a current density of 1 A/dm ² . Next, it was sufficiently washed with water about 5 times to remove non-electrodeposited graphite powder, and then dried to prepare a silver carbon plated specimen having a silver carbon plated layer (8 μm in thickness) on the surface.

Example 2

A silver carbon plating solution was prepared in the same manner as in Example 1, except that 120 g/L of the graphite suspension prepared in Preparation Example 1 was added to the dispersion treatment.

Example 3

A silver carbon plating solution was prepared in the same manner as in Example 1, except that 160 g/L of the dispersion-treated graphite suspension prepared in Preparation Example 1 was added.

Comparative Example 1

It was carried out in the same manner as in Example 1, but silver plating was performed without adding a graphite suspension, and a commercially available organic type post-treatment agent was used for post-treatment.

Comparative Example 2

Carried out in the same way as in Example 1, A silver carbon plating solution was prepared by adding 16 g/L of CNT (MWNT, Multi walled nanotube) without adding graphite suspension.

Comparative Example 3

In the same manner as in Example 1, a silver carbon plating solution was prepared by adding 16 g/L of CNT (SWNT, Single walled nanotube) without adding a graphite suspension.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 menstruum 1L 1L 1L 1L 1L 1L KAg(CN) ₂ (g/L) 40 40 40 40 40 40 KCN(g/L) 100 100 100 100 100 100 K ₂ CO ₃ (g/L) 10 10 10 10 10 10 KOH (g/L) 5 5 5 5 5 5 Metal polish (mg/L) 4 4 4 4 4 4 nonionic surfactant
(ml/L) 2 2 2 2 2 2 Distributed
Graphite suspension (g/L) 80 120 160 - - - CNT (MWNT, Multi-walled nanotube) (g/L) - - - - 16 - CNT(SWNT,Single walled nanotube)(g/L) - - - - - 16 Plating solution pH/temperature 12.5/20℃ 12.5/20℃ 12.5/30℃ 12.5/20℃ 12.5/20℃ 12.5/20℃

Experimental Example 1: Carbon Vacancy Rate of Silver Carbon Plating Layer

Carbon vacancies of the metal contact terminals prepared in Examples and Comparative Examples were measured, and the results are shown in Table 2 below. In addition, the measurement method was measured with an Energy Dispersive X-Ray Spectrometer (EDS) using OXFORD's X-MAX20, and mapping images for Examples and Comparative Examples are shown in FIG.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Carbon vacancy rate (% by weight) 5.50 7.12 7.57 - 1.02 1.24

Experimental Example 2: Measurement of discoloration resistance, abrasion resistance, conductivity, heat resistance, and lubricity of silver carbon plating layer

(1) Measurement of discoloration resistance

Discoloration resistance of the silver carbon plating layers prepared in Examples and Comparative Examples was evaluated by performing a K ₂ S discoloration test, and the discoloration test was evaluated by measuring the discoloration time in a 1% K ₂ S aqueous solution. After soaking for 3 hours, discoloration was evaluated. (KSM ISO2812-4)

The surface image after measuring the discoloration resistance for Example 1 is shown in FIG. 2 . And, the immersion time is shown in Table 3 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Immersion time (minutes) 180 180 180 10 180 180

(2) wear resistance measurement

The abrasion resistance of the silver carbon plating layer of Examples and Comparative Examples was judged by looking at whether the plating layer was peeled off when reciprocating 1,000 times at a sliding distance of 10 mm and a sliding speed of 3 mm/sec with a constant load of 2N using an abrasion tester do.

(3) Conductivity measurement

The conductivity of the silver carbon plating layer prepared in Examples and Comparative Examples was measured by measuring the contact resistance of the silver carbon plating layer formed portion and the silver carbon plating layer not formed portion of Comparative Example 1 Measurement of the plating layer without the silver carbon plating coating layer formed Values were determined on a 100% basis. For contact resistance, the change in contact resistance according to the load change was measured using an electrical contact simulator (CRS-1, Yamasaki) manufactured based on ASTM-B667. The contact resistance per specimen was measured 5 times and the average value is shown in Table 4.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 load 50g 0.0177 0.0176 0.0176 0.0175 0.0180 0.0184 load 75g 0.0162 0.0160 0.0159 0.0157 0.0171 0.0173 load 100g 0.0156 0.0152 0.0151 0.0151 0.0162 0.0164 Conductivity (%) 97.51% 98.96% 99.37% 100% 93.78% 92.13

(4) heat resistance

As for the heat resistance of the silver carbon plating layers prepared in Examples and Comparative Examples, since the silver plating layer is rapidly oxidized at 350 ° C, heat treatment was performed at 450 ° C for 10 minutes in a nitrogen atmosphere to evaluate the heat resistance by checking whether the surface was oxidized. ( Manufacturer: Daeheung Science, product name: DF-333GFS). And, a photograph after high-temperature heat treatment is shown in FIG. 3 .

(5) Lubricity

Load cell: 29N, speed: 150mm/min, vertical load: 2.09N (the sum of the weight of the weight 200g (1.96N) and the weight of the sample) value), the friction coefficient was measured with the friction material (STS) to evaluate the lubricity, and the results are shown in Table 5 below.

division Vertical load (N) Average value of static friction coefficient (-) Mean value of dynamic friction coefficient (-) Example 1 2.09 0.149 0.151 Example 2 2.09 0.145 0.148 Example 3 2.09 0.142 0.148 Comparative Example 1 2.09 0.148 0.165 Comparative Example 2 2.09 0.153 0.158 Comparative Example 3 2.09 0.155 0.157

The friction coefficient is the relative ratio of the frictional force divided by the vertical contact force, and is divided into static friction coefficient and dynamic friction coefficient. The static friction coefficient is the value between two objects at rest, and the dynamic friction coefficient is the relative As a value that is in motion, the friction coefficient appears higher in the case where lubricity is not present than in the case where lubricity exists.

In addition, the results of discoloration resistance, abrasion resistance, conductivity, heat resistance, and lubricity measurements previously performed are shown in Table 6 below.

division discoloration resistance wear resistance
(peeling occurs) continuity measurement
(%) heat resistance lubricity
(average of dynamic friction coefficient) Example 1 no discoloration clear 97.51 clear 0.151 Example 2 no discoloration clear 98.96 clear 0.148 Example 3 no discoloration clear 99.37 clear 0.148 Comparative Example 1 discoloration occurs peeling occurs 100 oxidized 0.165 Comparative Example 2 Some discoloration occurs peeling occurs 93.78 clear 0.158 Comparative Example 3 Some discoloration occurs clear 92.13 clear 0.157

As can be confirmed through Table 6, which summarizes the physical property measurement results, it was confirmed that the silver carbon-coated specimens of Examples 1 to 3 had excellent discoloration resistance, wear resistance, electrical conductivity, heat resistance, and lubricity.

On the other hand, Comparative Example 1 in which the plating process was performed with a silver plating solution without adding the graphite suspension was found to have significantly poor overall physical properties.

In addition, Comparative Examples 2 and 3, which were plated with a silver plating solution containing MW-CNT or SW-CNT, showed poorer results than Examples 1 to 3 in terms of discoloration resistance and conductivity.

Through the above examples and experimental examples, the silver carbon plating layer plated with the silver carbon plating solution of the present invention has excellent corrosion resistance and discoloration resistance because the carbon component (C) is uniformly distributed in the plating layer, as well as heat resistance, wear resistance and It was confirmed that the electrical characteristics were also excellent.

Claims (10)

delete delete KAg(CN) ₂ 30 ~ 45g/L, KCN 80 ~ 135g/L, K ₂ CO ₃ 5 ~ 40g/L, KOH 2 ~ 15g/L, metal polish 2 ~ 8 mg/L, nonionic surfactant 1 ~ 7 ml / L, including 50 ~ 200 g / L of the graphite suspension dispersed and water as a solvent,
The metal brightener is a Se-based compound containing at least one selected from Na ₂ Se and Na ₂ SeO ₄ ; a Sb-based compound including at least one selected from K ₂ Sb ₂ C ₈ H ₄ O _12, O ₁₂ S ₃ Sb ₂ (Antimony sulfate), Sb ₂ O ₃ and Sb ₂ S ₅ ; and Bi ₂ O ₃ , BiCl ₂ and NaBiO ₃ Bi-based compound containing at least one selected from; Including one or more selected from among,
The nonionic surfactant includes at least one selected from polysorbate and octyldodeceth,
The dispersion-treated graphite suspension includes graphite powder from which hydrophobic organic materials are removed by oxidizing the surface of graphite powder having a particle size of 1 to 10 μm with an oxidizing agent; And a dispersion wetting agent; including,
The oxidizing agent includes at least one selected from sulfuric acid, nitric acid, hydrogen peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, potassium permanganate and potassium periodate,
The dispersion wetting agent is silver carbon plating solution with excellent discoloration resistance, abrasion resistance, conductivity, heat resistance and lubricity, characterized in that it comprises at least one selected from glycol ethers and lauryl alcohol ethoxylate. delete delete delete delete A first step of preparing a copper-based or copper-alloy-based component on which a silver (Ag) plating layer is formed; and
The plating treatment method of the silver carbon plating solution comprising a second step of plating the surface of the silver plating layer with the silver carbon plating solution of claim 3 to form a silver carbon (Ag-C) plating layer. [Claim 9] The method of claim 8, wherein the plating in the second step is electroplating at 18 to 30°C and pH of 11 to 13. [Claim 9] The method of claim 8, wherein the silver carbon plating layer has a carbon vacancy amount of 1 to 10% according to EDS mapping analysis.

Images