JPH08311686A - Plated product excellent in stain resistance in water - Google Patents

Abstract

PURPOSE: To prevent the sticking of hydrobios to a metallic product and plastic product to be used in water and the propagation thereof, and to enhance stain resistance in water. CONSTITUTION: 1. In this plated product excellent in stain resistance in water, a copper-cobalt alloy-plated layer containing 22-88wt.% copper is provided on a metal or a plastic. 2. In the plated product excellent in anti-microbial property, (1) at least one kind among nickel-plated layer, nickel alloy-plated layer and cobalt alloy-plated layer and (2) a copper-cobalt alloy-plated layer containing 22-88wt.% copper are provided in order on the metal or the plastic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for imparting a high degree of underwater stain resistance to products made of metal and plastic.

[0002]

2. Description of the Related Art Metal and plastic instruments and devices for use in water such as seawater (hereinafter simply referred to as products) include various algae, various shellfish such as barnacles (hereinafter simply referred to as aquatic organisms). However, it takes a lot of labor to remove it. Further, when the removed aquatic organisms rot, they give off a bad odor, and it is necessary to prevent aquatic organisms from adhering to the product.

Further, when aquatic organisms propagate inside the piping of a cooling system such as a power plant or a ship that uses seawater as cooling water, the cooling capacity is lowered, and the operation of the power plant or the operation of the ship is reduced. Since it may cause problems, it is necessary to suppress the attachment or reproduction of aquatic organisms.

[0004] Conventionally, for example, there is an example in which the propagation of aquatic organisms is prevented by introducing a chemical such as sodium hypochlorite into the seawater intake for cooling. Some companies are unable to use such drugs due to agreements with fishery associations.

Further, in order to prevent aquatic organisms from adhering to metal products in water such as seawater, plating of cobalt and its alloys (excluding cobalt-copper alloy) or copper plating is performed. . However, the underwater antifouling effect of these metal plating or alloy plating in water does not last very long. this is,
It is presumed that this is because a hydroxide or oxide film is formed on the plating surface and the elution of cobalt ion or copper ion which is an antibacterial chemical species is inhibited. Of course, if the film formed on the plating surface is periodically removed by physical or chemical means, the effect is again exhibited, but in consideration of the use environment of water, removal of the film by such means is Difficult and impractical.

[0006]

Therefore, the present invention aims to prevent adhesion of aquatic organisms to metal and plastic products used in water and their propagation (improve antifouling property in water). The main purpose is.

[0007]

The present inventor has conducted research in view of the current state of the art as described above, and as a result, copper has been added in a specific ratio on the surface of metal and plastic products used in water. It has been found that the above object can be achieved in the case of forming a cobalt plating layer containing a.

Further, when a nickel plating layer or a nickel alloy plating layer is formed on the surface of a metal or plastic product and then a cobalt plating layer containing copper in a specific ratio is formed thereon, It has been found that the bond with the copper-cobalt alloy plating layer becomes stronger and the underwater antifouling property is maintained for a longer period.

That is, the present invention provides the following plated products having excellent antifouling properties in water: A plated product having excellent antifouling properties in water, which is provided with a copper-cobalt alloy plating layer containing 22 to 88% by weight of copper on metal or plastic.

[0010] 2. 22 to 88% by weight of (1) at least one of nickel plating layer, nickel alloy plating layer and cobalt plating layer and (2) copper on metal or plastic
A plated product with excellent antifouling properties in water, in which a copper-cobalt alloy plating layer containing it is sequentially provided.

In the present invention, a copper-cobalt plating layer is provided on the surface of a metal or plastic product.
As described above, it is known that cobalt plating or a part of cobalt alloy plating exhibits excellent underwater antifouling performance immediately after plating, but its effect decreases with the passage of time. However, in the present invention, 78 to 12% by weight of Co and 22 to 8% of Cu used as the plating layer metal are used.
In the case of a Co-Cu alloy composed of 8% by weight, excellent underwater antifouling performance is exhibited for a long period of time. The Co-Cu alloy according to the present invention exerts such excellent effects as follows.
It is presumed that it is due to the following reasons.

That is, when the Co--Cu alloy formed as a plating layer on the surface of a metal or plastic product corrodes in water, in the initial corrosion reaction, the Co-rich portion becomes an anode and cobalt ions are eluted, The Cu-rich portion becomes a cathode and OH ⁻ ions are generated (it is considered that H ₂ O ₂ is also generated). With the passage of time, the Co concentration on the anode side decreases with the elution of Co, and an oxide film is formed, so that the elution of Co ions decreases. At this point, the elution in the copper-rich portion is small and it is in a chemically active state. Therefore, due to the difference in potential, the copper-rich portion is divided into an anode and a cathode to cause a corrosion reaction, Cu ions are eluted from the anode side, and a production reaction of OH ⁻ ions and the like proceeds on the cathode side. If the reaction in this state continues for a while, the Cu concentration on the anode side of the copper-rich portion decreases with the elution of Cu, so that the Co-rich portion is exposed and the oxide film formed on the Co surface gradually dissolves. To do. In this way, the same corrosion reaction as in the initial stage is performed again. Since the elution of Co ions and the elution of Cu ions are repeated in this manner, the adhesion of aquatic organisms to the product surface and the growth on the product surface are effectively suppressed.

Co-C for metal or plastic
The u alloy plating layer may be formed in a state of a material before being processed into a product, or may be formed in a state of being processed into a product.

Alternatively, in the present invention, in order to improve the adhesion of the Co—Cu alloy plating layer to the metal product or the plastic product, at least the nickel plating layer, the nickel alloy plating layer and the cobalt plating layer are formed on the surface of the product. After forming one, Co78 ~ on it
A copper-cobalt plating layer composed of 12% by weight and 22 to 88% by weight of Cu can be provided.

The formation of the Co-Cu alloy plating layer is not particularly limited as long as a Co-Cu alloy plating layer having a Cu content of 22 to 88% by weight can be formed, but as an example, copper sulfate 10 g / l , Cobalt sulfate 20 g / l, potassium pyrophosphate 108 g / l and dipotassium tetraborate 40 g / l are used at a temperature of about 45 to 65 ° C., a pH of about 9.5, and an anode current density of 0.5 to 2 A / dm ²
It can be performed under moderate conditions. Examples of the anode material include a carbon plate, a graphite plate, platinum-coated titanium, and platinum-coated titanium alloy.

In the present invention, the Cu content is 2
When it is less than 2% by weight, it is difficult to form a Co—Cu alloy layer by a plating method, and Co
Is oxidized and the elution amount is reduced, and the antifouling effect in water is reduced. On the other hand, when the Cu content exceeds 88% by weight, the elution of Co is reduced and the antifouling effect in water is also lowered. The Cu content in the Co-Cu alloy is 50 to 7
More preferably, it is about 0% by weight.

The nickel plating layer, the nickel alloy plating layer, or the cobalt plating layer as the underlying plating layer on the metal or plastic can be formed by a usual electroplating method and / or chemical plating (electroless plating) method. . The thickness of the base plating layer is not particularly limited, but is usually about 1 to 30 μm.

Then, according to a conventional method, Co is formed on the underlying plating layer by electroplating and / or chemical plating.
-Form a Cu alloy plating layer. The thickness of the Co—Cu alloy plating layer is not particularly limited, but is usually in the range of about 0.5 to 35 μm. Plating thickness is
It may be appropriately determined in consideration of the usage environment, and may be outside the above range.

Conventionally, in order to form a Co—Cu alloy plating layer on metal products and plastic products, various pretreatment steps (degreasing step, washing step, catalyst applying step, activation step, etc.), plating layer forming method. (Electroplating method, chemical plating method or electroless plating method, etc.) are adopted. In the present invention, these known methods and conditions in the pretreatment step can be adopted as they are.

More specifically, the iron-based metal product according to the present invention has, for example, (a) degreasing-water washing-acidic aqueous solution soaking-water washing-nickel plating-water washing-Co / Cu alloy plating layer formation, (b) degreasing -Washing-Dip in acidic aqueous solution-Water washing-Co plating layer formation-Water washing-Co / Cu alloy plating layer formation,
(C) Degreasing-washing-immersing in acidic aqueous solution-washing-Co / Cu
It can be manufactured by a process such as forming an alloy plating layer.

Copper products and copper alloy products (for example, brass products) can be manufactured, for example, by the steps of (d) degreasing-washing-immersing in an acidic aqueous solution-washing-forming a Co / Cu alloy plating layer. However, it can also be manufactured according to the above (a) to (c).

Further, a plastic product can also be pretreated by a known process in the same manner as described above, and then a cobalt-copper alloy plating layer can be formed. As a matter of course, in the case of plastic, an appropriate pretreatment process according to the type is adopted. For example, for ABS resin, degreasing-washing-etching (chromic anhydride / sulfuric acid mixed aqueous solution) -neutralization (in an acidic aqueous solution containing a reducing agent, hexavalent chromium ions derived from chromic anhydride are attached). Three
(Reduce to valent chromium ions) -Washing-Catalyst application step (palladium chloride / stannous chloride) -Water washing-Activation step (sulfuric acid aqueous solution) -Electroless nickel plating layer formation-Sulfuric acid aqueous solution immersion-Water washing-Nickel plating layer formation The cobalt-copper alloy plating layer can be formed by a known process such as forming a cobalt / copper alloy plating layer.

[0023]

EFFECTS OF THE INVENTION According to the present invention, the underwater antifouling effect of metal products and plastic products can be remarkably enhanced, and the effect lasts for a long time.

[0024]

EXAMPLES Reference examples, examples and comparative examples are shown below,
The features of the present invention will be further clarified.

The underwater antifouling test and its judgment in Examples and Comparative Examples were carried out as follows.

1) Underwater antifouling test 150 mm × 210 mm × 0.3 mm test piece (for stainless steel and mild steel) or 150 mm × 210 mm × 1.3 mm test piece (AB
After forming a predetermined plating layer on a test piece of S resin) or a 150 mm × 210 mm × 1 mm test piece (in the case of polyamide), the surface of seawater is maintained for 5 months from June to October when the growth of organisms is the most active. It was installed about 1.5 m below and the state of attachment and growth of organisms was observed.

2) Judgment The state of growth of biofouling on the test piece was observed with the naked eye, and the antifouling property in water was judged by the following five-step evaluation method.

1: Almost no adhesion. 2: Slightly adhered. 3: Adhesion is slightly large. 4: A lot of adhesion. 5: Remarkably large adhesion.

Comparative Example 1 A stainless steel test piece (SUS304) was electrolytically degreased, washed with water,
Then, soak in 10% hydrochloric acid for 3 minutes, wash with water, and then use a plating bath of nickel chloride 240g / l and concentrated hydrochloric acid 120ml / l.
Electrolysis was carried out for 2 minutes at a bath temperature of 20 ° C. and a cathode current density of 20 A / dm ² . Then, after washing this test piece with water, nickel sulfate 240 g / l,
Using a plating bath of nickel chloride 45g / l and boric acid 30g / l, bath temperature 48-53 ℃, cathode current density 4A / dm ² under air stirring.
Electrolysis for 58 minutes to form a nickel plating layer of about 35 μm.

The judgment value of the underwater antifouling property test of the obtained test piece was 4.

Comparative Example 2 A nickel plating layer of about 35 μm was formed in the same manner as in Comparative Example 1 except that a mild steel test piece was used instead of the stainless steel test piece.

The judgment value of the underwater stain resistance test of the obtained test piece was 4.

Comparative Example 3 A stainless steel test piece (SUS304) was electrolytically degreased, washed with water,
Then, soak in 10% hydrochloric acid for about 3 minutes, wash with water, and then use a plating bath of 240 g / l nickel chloride and 120 ml / l concentrated hydrochloric acid for 2 minutes at a bath temperature of 18 ° C and a cathode current density of 20 A / dm ^2. Electrolyzed. Then, after washing this test piece with water, nickel sulfate 24
Using a plating bath of 0 g / l, 45 g / l of nickel chloride and 30 g / l of boric acid, electrolyze for 16 minutes at a bath temperature of 48 to 53 ° C. and a cathode current density of 4 A / dm ² under agitation of air to about 10 μm. Of nickel plating layer was formed. Then, after washing this test piece with water, cobalt sulfate 120 g / l, cobalt chloride 30 g / l, boric acid 3
Using a 0 g / l cobalt plating bath, electrolyze for 43 minutes at a bath temperature of about 62 ° C and a cathode current density of 4 A / dm ² under air agitation for about 25 μm.
m cobalt plating layer was formed.

The judgment value of the underwater antifouling test of the obtained test piece was 3.

Comparative Example 4 A cobalt plating layer having a thickness of about 35 μm was formed in the same manner as in Comparative Example 3 except that a mild steel test piece was used instead of the stainless steel test piece.

The judgment value of the underwater antifouling property test of the obtained test piece was 3.

Comparative Example 5 A stainless steel test piece (SUS304) was electrolytically degreased and washed with water,
Then, soak in 10% hydrochloric acid for 3 minutes, wash with water, and then use a plating bath of nickel chloride 240g / l and concentrated hydrochloric acid 120ml / l.
Electrolysis was performed at a bath temperature of 18 ° C. and a cathode current density of 20 A / dm ² for about 2 minutes.
Then, after washing this test piece with water, nickel sulfate 240 g /
l, nickel chloride 45g / l and boric acid 30g / l plating bath, bath temperature 48-53 ℃, cathode current density 4A under air stirring
Electrolysis was performed at / dm ² for 16 minutes to form a nickel plating layer of about 10 μm. Then, after washing this test piece with water, copper sulfate
Using a copper plating bath of 200 g / l and sulfuric acid 100 g / l, electrolyze for 41 minutes at a bath temperature of about 20 to 25 ° C and a cathode current density of 3 A / dm ² under air stirring to form a copper plating layer of about 25 μm. Formed.

The judgment value of the underwater antifouling property test of the obtained test piece was 3.

Example 1 A stainless steel test piece was electrolytically degreased, washed with water, and then washed with water.
% Hydrochloric acid for about 3 minutes and washed with water.

Then, this stainless steel test piece was electroplated for 2 minutes at a cathode current density of 20 A / dm ² using a nickel plating bath containing 240 g / l of nickel chloride and 120 ml / l of concentrated hydrochloric acid. Next, the test piece was washed with water, and further, using a matte nickel plating bath of 240 g / l of nickel sulfate, 45 g / l of nickel chloride and 30 g / l of boric acid, with a cathode current density of 4 A / dm ² under air stirring. Electrolytic plating is performed for 16 minutes and the thickness is about 10μ
m nickel plating layer was formed.

Then, the stainless steel test piece on which the nickel plating layer was formed was washed with water, and then 10 g / l of copper sulfate,
Using a copper-cobalt alloy plating bath containing 20 g / l of cobalt sulfate, 108 g / l of potassium pyrophosphate and 40 g / l of dipotassium tetraborate, at a bath temperature of 55 ° C. and a cathode current density of 1 A / dm ² .
It was electrolyzed for 120 minutes, washed with water and dried. Co / C obtained
The thickness of the u alloy plating layer was about 25 μm (Cu content 57% by weight).

The judgment value of the underwater antifouling property test of the obtained test piece was 2.

Example 2 A mild steel test piece was electrolytically degreased, washed with water, then immersed in 10% hydrochloric acid for about 2 minutes, washed with water and immersed in 10% hydrochloric acid for about 3 minutes,
Washed with water.

Next, this mild steel test piece was filled with 240 g of nickel chloride.
Electrolytic plating was performed for 2 minutes at a cathode current density of 20 A / dm ² using a nickel plating bath containing / l and concentrated hydrochloric acid of 120 ml / l.
Next, after washing the test piece with water, further nickel sulfate 240 g /
Cathode current density 4A under air agitation using a dull nickel plating bath of l, nickel chloride 45g / l and boric acid 30g / l
Electroplating was performed at / dm ² for about 16 minutes to form a nickel plating layer having a thickness of about 10 μm.

Next, after washing the mild steel test piece on which the above nickel plating layer was formed, with water, 22 g / l of copper sulfate, 20 g / l of cobalt sulfate, 148 g / l of potassium pyrophosphate and 40 g / l of dipotassium tetraborate were added. Using a copper-cobalt alloy plating bath, electrolysis was performed for 120 minutes under conditions of a bath temperature of 55 ° C. and a cathode current density of 1 A / dm ² , washed with water, and dried. The thickness of the obtained Co / Cu alloy plating layer was about 25 μm (Cu content: 71% by weight).

The judgment value of the underwater antifouling property test of the obtained test piece was 2.

Example 3 A mild steel test piece was electrolytically degreased, washed with water, then immersed in 10% hydrochloric acid for 2 minutes, washed with water, immersed in 10% hydrochloric acid for 3 minutes, and washed with water.

Then, this mild steel test piece was subjected to nickel chloride 24
Using a nickel plating bath containing 0 g / l and concentrated hydrochloric acid 120 ml / l, electroplating was performed for 2 minutes at a cathode current density of 20 A / dm ² . Then, after washing the test piece with water, nickel sulfate is further added.
Using a matte nickel plating bath of 240g / l, nickel chloride 45g / l and boric acid 30g / l, bath temperature 48-53 under air stirring
Electrolytic plating was performed at a temperature of 4 ° C. and a cathode current density of 4 A / dm ² for about 16 minutes to form a nickel plating layer having a thickness of about 10 μm.

Then, the mild steel test piece on which the nickel plating layer was formed was washed with water and then copper sulfate 5.8 g / l, cobalt sulfate 20 g / l, potassium pyrophosphate 95 g / l and dipotassium tetraborate 40 g / l. Using the copper-cobalt alloy plating bath of No. 1, electrolysis was performed for 120 minutes under conditions of a bath temperature of 55 ° C. and a cathode current density of 1 A / dm ² , washed with water, and dried. The thickness of the obtained Co / Cu alloy plating layer was about 25 μm (Cu content 35% by weight).

The judgment value of the underwater antifouling property test of the obtained test piece was 2.

Example 4 ABS resin test pieces were immersed in a washing solution (sodium carbonate 10 g / l, sodium phosphate 20 g / l and surfactant 2 ml / l) at a temperature of 50.
After immersing at ℃ for 4 minutes and washing with water, it was immersed for 10 minutes at a temperature of 67 ℃ in a mixed aqueous solution of chromic anhydride 400 g / l and sulfuric acid 400 g / l for etching.

Next, the above ABS resin test piece was washed with water, immersed in a mixed aqueous solution of concentrated hydrochloric acid 50 ml / l and acidic sodium sulfite 8 ml / l for 2 minutes, and then washed with water to be neutralized.

Then, this test piece was treated with stannous chloride 10 g / l.
Then, it was immersed in a mixed aqueous solution of 8 ml / l of concentrated hydrochloric acid for 5 minutes, washed with water, then immersed in a mixed aqueous solution of 0.2 g / l of palladium chloride and 3 ml / l of concentrated hydrochloric acid for 4 minutes, and washed with water.

Next, the ABS resin test piece that had been subjected to the above treatment was treated with nickel sulfate 21 g / l, lactic acid 28 g / l, propionic acid 2.
It was immersed in an electroless nickel plating bath containing 3 g / l and 21 g / l hypophosphorous acid at a temperature of 90 ° C. and a pH of 5.2 for 10 minutes, washed with water, further immersed in an aqueous solution of 100 g / l sulfuric acid, and washed with water.

Next, the ABS resin test piece which has been subjected to the above treatment is immersed in a nickel plating bath of nickel sulfate 240 g / l, nickel chloride 45 g / l and boric acid 30 g / l, and the bath temperature is 35 ° C.
After electrolysis was carried out for 7 minutes at a cathode current density of 1 A / cm ² , it was washed with water to form a nickel plating layer.

Next, the above ABS resin test piece was immersed in a nickel plating bath of nickel sulfate 240 g / l, nickel chloride 45 g / l and boric acid 30 g / l, and the temperature of the bath was 48 to 53 while stirring with air.
After electrolysis for 16 minutes at ℃, cathode current density 4A / cm ² , washed with water,
A matte nickel plating layer (about 10 μm) was formed.

Then, the above ABS resin test piece was treated with copper sulfate.
22g / l, cobalt sulfate 20g / l, potassium pyrophosphate 148g / l
Using a copper-cobalt alloy plating bath containing 40 g / l of dipotassium tetraborate and a bath temperature of 55 ° C. and a cathode current density of 1 A / dm ² , electrolysis was performed for 80 minutes, washing with water, and drying. Obtained Co
/ Cu alloy plating layer has a thickness of about 17 μm (Cu content 71
% By weight).

The judgment value of the underwater antifouling property test of the obtained test piece was 2.

Example 5 A polyamide test piece was immersed in a cleaning solution having a composition of 100 g / l of sodium hydroxide and 2 ml / l of a surfactant at a temperature of 60 ° C. for 10 minutes, washed with water, and then immersed in an aqueous solution of 80 ml / l of hydrochloric acid. 25 ° C
After immersing in water for about 3 minutes and washing with water, it was immersed in a mixed aqueous solution of concentrated hydrochloric acid 5 ml / l and acidic sodium sulfite 3 g / l for 2 minutes, washed with water and washed.

Next, the polyamide test piece washed as described above was immersed in a mixed solution of 10 g / l of stannous chloride and 8 ml / l of concentrated hydrochloric acid for 5 minutes, washed with water, and then with 0.3 g / l of palladium chloride. It was immersed in a mixed aqueous solution of concentrated hydrochloric acid of 3 ml / l for 4 minutes and washed with water to activate and apply a catalyst.

Next, the test piece pretreated as described above was treated with nickel sulfate 21 g / l, lactic acid 28 g / l and propionic acid 2.3 g / l.
Using an electroless Ni plating bath consisting of 21 g / l of hypophosphorous acid, electroless Ni plating was performed under the conditions of temperature 90 ° C., pH 5.2, and immersion time 10 minutes.

Next, the test piece after the Ni electroless plating treatment was washed with water, then immersed in an aqueous solution of sulfuric acid 100 g / l and washed with water,
Next, electrolytic plating was performed using a nickel electrolytic plating bath having a composition of 240 g / l of nickel sulfate, 45 g / l of nickel chloride and 30 g / l of boric acid. In the electrolytic plating treatment, electrolysis was carried out for 7 minutes at a bath temperature of 35 ° C. and a cathode current density of 1 A / dm ² , followed by washing with water. As a result, a nickel plating layer having a total thickness of about 1 μm was formed.

Then, a polyamide test piece plated with electrolytic Ni was plated with dull nickel. The bath composition is
240g / l nickel sulphate, 45g / l nickel chloride and 3 boric acids
It is 0 g / l. For plating operation, the bath temperature should be 48 to 53 with air stirring.
It was carried out at a temperature of 4 ° C. and a cathode current density of 4 A / dm ² for 16 minutes to form a nickel plating layer having a thickness of 10 m.

Then, the polyamide test piece on which the matte nickel plating layer was formed as described above was washed with water and Co / C
A u alloy plating layer was formed. The composition of the Co / Cu alloy plating bath was copper sulfate 10 g / l, cobalt sulfate 20 g / l, potassium pyrophosphate 108 g / l and dipotassium tetraborate 40 g / l. Current density 1A / dm ²
It electrolyzed for 96 minutes on condition of, was washed with water, and was dried. C obtained
The thickness of the o / Cu alloy plating layer was about 20 μm (Cu content 57% by weight).

The judgment value of the underwater antifouling property test of the obtained test piece was 2.

Claims (2)

[Claims] 1. Copper 22 to 88 for metal or plastic
A plated product having a copper-cobalt alloy plating layer containing 50% by weight and having excellent antifouling properties in water. 2. A metal or plastic is sequentially provided with (1) at least one of a nickel plating layer, a nickel alloy plating layer and a cobalt plating layer and (2) a copper-cobalt alloy plating layer containing 22 to 88% by weight of copper. A plated product with excellent antifouling properties in water.