WO2006079278A1

WO2006079278A1 - Decorative laminate, plating solution and plating method for forming the decorative layer, and products use this decorative layer

Info

Publication number: WO2006079278A1
Application number: PCT/CN2006/000109
Authority: WO
Inventors: Chin-Gar Wu
Original assignee: Roring Industries (Xiamen), Ltd.
Priority date: 2005-01-25
Filing date: 2006-01-23
Publication date: 2006-08-03
Also published as: CN1811017A

Abstract

The present invention involves a decorative laminate which can be used in ornamental members, watch or mobile telephone to obtain a bright finish. This laminate includes a cobalt layer(the concention of cobalt is at least 99%) or a Co-Fe (Mg) alloy layer(it includes Co 95-98%,Fe 1-5% and /or Mg 0.05-0.2%). The Co plating layer can substitute for the conventional Ni plating layer due to their similarly physical and chemical properties, and the Ni releasing amount is less than 0.05ppm, so the thus obtained products are suitable for the buyers who are allergic to Ni. The present invention further provides a plating solution and a plating method for forming this decorative laminate on workpiece.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative plating layer, a plating liquid and a method for forming the decorative plating layer, and a product to which the decorative plating layer is applied. BACKGROUND OF THE INVENTION Eyeglass frames, accessories (such as earrings, watches, jewelry, necklaces, bracelets), mobile phones, or everyday items (such as 3⁄4 buckles, coins, keys) are often provided with decorative coatings on the surface. The coating structure of conventional coatings generally contains nickel plating. However, nickel is the most common allergen for allergic contact dermatitis. For people with special constitution, skin contact with substances containing nickel metal can induce cellular immune reactions. Therefore, the development of nickel-based processes has become a hot topic in the field of decorative plating.

At present, copper-tin alloy coating is the most common nickel-based coating, but the reduction potential of copper and tin is very different (the reduction potential of copper is +0.52V, the reduction potential of tin is -0.14V), so pyrophosphate and lemon are used. Acid stannate or HEDP copper-plated tin alloys can only obtain copper-tin alloy coatings with low tin content (<15%). However, the appearance of low tin bronze is pink or golden yellow, and the hardness of the coating is low, which cannot meet the requirements of nickel plating. In contrast, high tin bronze (40-50% tin) has a silver-white appearance and high hardness, and is a suitable nickel-plated coating. However, in order to achieve this high proportion of tin bronze plating, cyanide ions must be used as a complexing agent to bring the potential of copper tin gold to less than 200 mV, and copper and tin can be co-deposited. However, since gaseous or soluble salt cyanide is highly toxic, during the electroplating process, cyanide fumes are easily absorbed by the operator's skin and respiratory tract into the practitioner. The harm of cyanide to the human body is divided into acute and chronic effects. Acute poisoning is lightly irritating to the eyes and upper respiratory tract, while heavy stimuli cause paroxysmal stagnation of blood pressure, accompanied by cerebral edema and respiratory failure. Chronic effects are characterized by neurasthenia syndrome. Dizziness, headache, fatigue, chest tightness and abdominal pain. At the same time, the cost of sewage treatment of cyanide is also relatively expensive. In addition, high-tin bronze has the disadvantages of low cathode current efficiency, high energy consumption, poor bath stability, and poor thermal stability of the coating.

Therefore, there is an urgent need to develop an environmentally conscious decorative coating that exceeds the performance of nickel plating to meet consumer demand. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a decorative coating for replacing a conventional nickel plating.

Another object of the present invention is to provide an electroplating for forming the aforementioned decorative plating layer. Liquid.

It is still another object of the present invention to provide a method for forming the aforementioned decorative plating. It is still another object of the present invention to provide a product for applying the aforementioned decorative plating which is resistant to skin nickel allergy.

To achieve the above object, the technical solution of the present invention is:

A decorative coating comprising a cobalt coating formed on a surface of a workpiece, the cobalt coating comprising at least 99% cobalt and up to 1% of unavoidable impurities by weight; and a color coating formed on the cobalt coating, The face color coating is selected from the group consisting of tin-cobalt-grey steel plating, palladium plating, gold plating, ruthenium plating, gold-palladium-copper alloy plating, white chrome plating, and black chrome plating.

The workpiece surface material is a copper alloy, and the decorative plating layer further comprises a pre-plated copper layer and a copper sulfate layer disposed between the workpiece and the cobalt plating layer.

When the surface of the workpiece is made of β-titanium, pure titanium or titanium alloy, the decorative plating layer further comprises a pre-plated nickel layer or a pre-gold plating layer disposed between the workpiece and the cobalt plating layer.

When the surface material of the workpiece is non-metal, the decorative plating layer further comprises a chemical nickel layer disposed between the workpiece and the cobalt plating layer.

A decorative coating comprising an alloy coating formed on a surface of a workpiece comprising 95 - 98% cobalt, 1 - 5% iron, and unavoidable impurities by weight.

The decorative plating layer further comprises a color plating layer formed on the alloy plating layer, wherein the surface color coating layer is composed of tin-cobalt gray steel plating layer, ba-plating layer, gold plating layer, ruthenium plating layer, gold-palladium-copper alloy plating layer, white chrome plating layer and black chrome plating layer. Elected among the ethnic groups.

The workpiece surface material is a copper alloy, and the decorative plating layer further comprises a pre-plated copper layer and a copper sulfate layer disposed between the workpiece and the alloy plating layer.

When the surface of the workpiece is made of β-titanium, pure titanium or titanium alloy, the decorative plating layer further comprises a pre-plated nickel layer or a pre-gold plating layer disposed between the workpiece and the alloy plating layer.

When the surface material of the workpiece is non-metal, the decorative plating layer further comprises a chemical nickel layer disposed between the workpiece and the alloy plating layer.

The alloy coating further comprises 0.05 - 0.2% magnesium.

A plating solution for forming a cobalt plating layer, comprising: 250 - 300 g/l of CoS0 ₄ · 7H ₂ 0; 30 - 60 g/l of sodium chloride; 30 - 40 g/l of boric acid; 0.1 to 0.5 g / l class I additive; and 5 - lOg / 1 class II additive; wherein class I additive is an organic compound containing C = 0, OC, C = N, N = N or N = 0 unsaturated bond, class II additive It is an organic compound having a structure of OC—C—S0 ₂ , C=C—S0 ₂ — or C≡C—C—S0 ₂ -- wherein the pH of the plating solution is not more than 4.

The class I additive is selected from the group consisting of trichloroethanol, coumarin butanediol, acridine and quinine; the class II additive is composed of saccharin, naphthalenesulfonic acid and p-methylsulfonate. Selected from the group consisting of amines.

A plating solution for forming a cobalt-iron alloy plating layer, comprising: 250 - 300 g/l of CoS0 ₄ · 7H ₂ 0; 1-lOg/l of FeS0 ₄ · 7H ₂ 0; 40 - 60 g/l of sodium chloride ; 35 - 55g/l Boric acid; 0.2 - 0.5g / l of Class I additives; and 4 _ 8g / l of Class II additives; wherein Class I additives contain 00, C = C, C = N, N = N or N = 0 is not saturated The organic compound of the bond, the type II additive is an organic compound containing a structure of C=C—C—S0 ₂ , C=C—S0 ₂ — or C≡C—C—S0 ₂ ; wherein the pH of the plating solution is not greater than 4.

The class I additive is selected from the group consisting of trichloroethanol, coumarin butanediol, acridine and quinine; the class II additive is composed of saccharin, "acid" and p- guanamine Selected among the ethnic groups formed.

A plating solution for forming a cobalt-iron-magnesium alloy plating layer, comprising: 240 - 280 g/l of CoS0 ₄ · 7H ₂ 0; 1 to 8 g/l of FeS0 ₄ · 7H ₂ 0; 0.5 to 2 g/l of MgS0 ₄ - 7H ₂ 0; 50 - 70g/l sodium chloride; 40 - 60g/l boric acid; 0.1 - 0.3g/l class I additive; and 5 - lOg/1 class II additive; For an organic compound containing a C-0, C=C, C=N, N=N or N=0 unsaturated bond, the class II additive contains C=C—C—S0 ₂ , C=C — S0 ₂ — or C≡C—C—S0 ₂ — an organic compound of the structure; wherein the pH of the plating solution is not more than 4.

The class I additive is selected from the group consisting of trichloroethanol, coumarin butanediol, acridine and quinine; the class II additive is composed of saccharin, acid and p-metylamine. Elected among the ethnic groups.

A method for forming a cobalt plating layer, comprising the steps of: adding a plating solution for forming a cobalt plating layer to a plating bath; immersing a cobalt plate in a plating solution of the plating bath as an anode; and immersing a workpiece The plating bath is used as a cathode in the plating solution; and a direct current is applied between the anode and the cathode; wherein the current density is controlled at 3 - 5 ASD, and the temperature in the plating bath is controlled at 50 - 60 °C.

A method for forming a cobalt-iron alloy plating layer, comprising the steps of: adding a plating solution for forming a cobalt-iron alloy plating layer to a plating bath; and plating a cobalt plate or a cobalt-iron alloy plate as an anode for immersing the plating bath In the liquid, the cobalt has a reverse iron content of about 2 - 5%; a workpiece is immersed in the plating solution of the plating bath as a cathode; and a direct current is passed between the anode and the cathode; wherein the current density is controlled at 2 - 5ASD, and the temperature in the plating bath is controlled at 50 - 60. C.

A method for forming a cobalt-iron-magnesium alloy plating layer, comprising the steps of: adding a plating solution for forming a cobalt-iron-magnesium alloy plating layer to an electroplating bath; and immersing a cobalt plate or a cobalt-iron alloy plate for electroplating of the electroplating bath In the liquid as an anode, the cobalt-iron alloy plate has an iron content of about 2 - 5 %; a workpiece is immersed in the plating solution of the plating bath as a cathode; and a direct current is passed between the anode and the cathode; wherein the current density is controlled 1.5 - 5ASD, and the temperature in the plating bath is controlled at 50 - 60 °C.

A decorative plating product comprising: a workpiece; and a decorative coating formed on the surface of the workpiece, the decorative coating comprising a cobalt coating or an alloy coating, wherein the cobalt coating comprises at least 99% cobalt by weight and Up to 1% of unavoidable impurities, the alloy coating contains 95 - 98% cobalt, 2 - 5 % iron and unavoidable impurities by weight.

The surface of the workpiece is made of a copper alloy, and the decorative coating further comprises a pre-plated layer and a A copper sulfate layer is disposed between the workpiece and the cobalt plating layer or the cobalt iron alloy layer.

The workpiece is made of a copper-nickel or copper-iron alloy having a nickel content of up to 30 - 40%, and the cobalt or cobalt-iron alloy layer has a thickness of at least 2 μm.

When the surface of the workpiece is made of β-titanium, pure titanium or titanium alloy, the decorative plating layer further comprises a pre-plated nickel layer or a pre-gold plating layer disposed between the workpiece and the cobalt plating layer or the cobalt-iron alloy layer.

When the surface of the workpiece is non-metallic, the decorative coating further comprises a layer of chemical nickel disposed between the workpiece and the cobalt coating or the cobalt-iron alloy layer.

It further comprises a color coating formed on the cobalt plating layer or the cobalt iron alloy layer, the color coating layer is tin cobalt cobalt copper plating, palladium plating, gold plating, ruthenium plating, gold palladium copper alloy plating, white chrome plating and black chrome Selected from the group consisting of plating.

The workpiece is selected from the group consisting of a spectacle frame, a watch, an earring, a ring, a necklace, a cell phone button, a cell phone case, and a mobile phone accessory.

The alloy coating further comprises 0.05 - 0.2% magnesium.

After adopting the above scheme, since the decorative coating of the present invention mainly comprises a cobalt plating layer (containing at least 99% cobalt) or a cobalt iron (magnesium) alloy plating layer (including 95 - 98% cobalt, 5% to 5% iron and / Or 0.05 - 0.2% traces of magnesium :), and cobalt and nickel have very similar physicochemical properties, so it can be used to replace the conventional nickel coating, the nickel dry amount is less than 0.05ppm, so the product can be supplied to special body to nickel For allergic consumers, there will be no allergies. The decorative coating is generally used to form a bright finish on a workpiece such as a jewelry, watch or mobile phone.

In addition, the cobalt plating solution of the present invention uses cobalt sulfate (250-300 g/l) as a main salt, sodium chloride (30-60 g/l) as an anode activator, and boric acid (30-40 g/l) as a Buffer to control the pH to no more than 4. Cobalt plating solution is also added with Class I additives (0.1-0.5 g/1) and Group II additives (5-10 g/1) to obtain a coating with good gloss and flatness. The stress and coating ductility can also be well controlled. . The class I additive is an organic compound containing a C=0, C=C, C=N, N=N or N=0 unsaturated bond, such as trichloroethanol, coumarin butanediol, acridine or quinine; The type II additive is an organic compound (for example, saccharin, p-toluenesulfonamide or naphthalenesulfonic acid) having a structure of C=C—C—S0 ₂ , OC—S0 ₂ — or C≡C—C—S0 ₂ —.

The cobalt iron plating solution of the present invention uses cobalt sulfate (250-300 g/l) and iron sulfate (1-10 g1) as the main salt, and sodium chloride (40-60 g/1) as the anode activator. Boric acid (35 - 55 g/1) is used as a buffer to control the pH to less than 4. In addition, the cobalt-iron plating solution is also added with a class I additive (0.2-0.5 g/1) and a class II additive (4- 8 g/l).

The invention further finds that adding a small amount of barium sulfate (0.5-2 g/1) to the cobalt iron electroplating solution can further improve the anti-tarnishing ability of the plating layer, but it is necessary to coat the surface layer and maintain the silver white color under oxygen without oxidative discoloration. Organic film (Varnish). In this embodiment, the other components of the plating solution are as follows: cobalt cobalt (240 - 280 g / 1), iron carbonate (1 - 8 g / l), sodium chloride (50 - 70 g / 1), boric acid ( 40-60 g/l), class I additives (0.1 - 0.3 g/1) and class II additives (5-10 g/l).

The present invention further provides a method of forming the aforementioned cobalt plating layer or alloy plating layer: First, in electroplating Adding the foregoing cobalt plating solution or cobalt iron plating solution to the tank; then, immersing a workpiece in the plating solution of the plating bath as a cathode, and a cobalt plate having a purity greater than 99% (for forming a cobalt plating layer or an alloy plating layer) Or a cobalt-iron plate with an iron content of about 2 - 5 % (used to form an alloy coating) as an anode in the plating bath immersed in the plating bath; finally, a direct current is applied between the anode and the cathode; current density of the cobalt plating layer is formed Controlled at 3 - 5ASD, and the temperature in the plating bath is controlled at 50 - 60 °C; the current density of the alloy plating layer is controlled at 2 - 5 ASD (the plating solution is not added with magnesium sulfate) or 1.5 - 5 ASD (the plating solution is added with magnesium sulfate). And the temperature in the plating bath is controlled at 50-60 Ό (the magnesium plating solution is not added with magnesium silicate) or 60-70 ° C (the plating solution is added with magnesium sulfate).

In addition, since the plating solution of the present invention does not contain cyanide, not only the sewage treatment cost is low, but also the health of the plating process worker can be effectively ensured; the decorative coating according to the present invention not only satisfies the needs of consumers, but also The process is environmentally conscious. BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have found that a decorative coating which replaces a conventional nickel plating layer can be developed by utilizing physicochemical properties of cobalt and nickel (see Table 1 below).

Table I

The decorative plating according to an embodiment of the present invention mainly comprises a cobalt plating layer instead of a conventional nickel plating layer formed on a surface of the workpiece, the cobalt plating layer comprising at least 99% of cobalt and up to 1% of unavoidable impurities by weight. .

The plating solution for forming the aforementioned cobalt plating layer uses cobalt sulfate (CoS0 ₄ · 73⁄40 ) (250 - 300 g / 1 ) as a main salt, and sodium chloride ( 30 - 60 g / 1 ) as an anode activator, boric acid (30 - 40 g/1 ) As a buffer to control the pH to no more than 4. In addition, the cobalt plating solution is also added with a class I additive (0.1 - 0.5 g/1) class II additive (5 - 10 g/1) to obtain a coating with good gloss and flatness, and the stress and coating ductility can also be controlled. good. Class I additives are organic compounds containing c=o, OC, C=N, N=N or N=0 unsaturated bonds, such as trichloroethanol, coumarin butanediol, acridine or quinine; II The additive is an organic compound (for example, saccharin, p-toluenesulfonamide or naphthalenesulfonic acid) having a structure of C=C—C—S0 ₂ , C=C — S0 ₂ — or C≡C—C—S0 ₂ —.

Since the cobalt plating layer and the nickel plating layer have the same problem of oxidative darkening in an aerobic environment, it is preferable to apply a layer of color plating on the cobalt plating layer by electroplating. (surface plating), such as tin-cobalt-grey steel plating, thin chrome (such as white chrome plating and black chrome plating) or precious metal plating (such as palladium plating, gold plating, ruthenium plating, and gold-palladium-copper alloy plating), Increase its corrosion resistance and aesthetics.

A decorative coating according to another embodiment of the present invention, which mainly comprises a cobalt-iron alloy plating layer instead of a conventional nickel plating layer formed on a surface of the workpiece, the cobalt-iron alloy plating layer comprising at least 95 - 98% cobalt, 5% to 5% by weight Iron and inevitable impurities. Since the cobalt-iron alloy coating can overcome the disadvantage that the cobalt plating layer is easily discolored in oxygen, the cobalt-iron alloy plating layer can be coated with a color coating layer to achieve durability and no discoloration, but the surface layer is Maintaining silver whiteness under oxygen does not oxidize and discoloration requires coating of organic film (Varnish). In addition, cobalt-iron alloy coating has higher corrosion resistance and toughness than conventional bright nickel plating, and hardness is equivalent to that of nickel plating, so it can replace bright nickel. The coating is used as a decorative coating.

The plating solution for forming the cobalt-iron alloy plating layer is cobalt sulfate (250-300 g/l) and iron sulfate (1 - lOg/1) as the main salt, and sodium chloride (40-60 g/l) as the anode activator. Boric acid (35 - 55 g / 1 as a buffer to control the pH value is not more than 4. In addition, cobalt iron plating solution is also added to the class I additive (0.2 - 0.5 g / 1) and class II additives (4 - 8 g / 1) ).

The invention further finds that adding a small amount of magnesium sulfate (0.5-2 g/l) to the plating solution can further improve the anti-tarnishing ability of the plating layer, but it is necessary to apply the organic film to be the surface layer and maintain the silver white color under oxygen without oxidative discoloration. (Vamish). In this embodiment, the other components of the plating solution are as follows: cobalt ruthenate (240 - 280 g / 1), iron sulfate (1 - 8 g / 1), sodium chloride (50 - 70g / l), boric acid ( 40 - 60 g/1), Class I additives (0.1 - 0.3g/l) and Group II additives (5 - 10 g/l). When a small amount of magnesium sulfate (0.5 - 2 g/1) is added to the plating solution, the formed plating layer contains 0.05-0.2% trace of magnesium in addition to cobalt and iron.

The cobalt plating layer or the alloy plating layer according to the present invention can be formed by an electroplating method using the aforementioned plating solution. The current density for forming the cobalt plating layer is preferably controlled at 3 - 5 ASD, and the temperature in the plating bath is preferably controlled at 50 - 60 °C. The current density of the alloy plating layer is preferably controlled at 2 - 5 ASD (electroplating solution into magnesium sulfate) or 1.5 - 5 ASD (electroplating solution is added with magnesium sulfate), and the temperature in the plating bath is preferably controlled at 50 - 60 ° C (electroplating) The liquid is not added with magnesium succinate or 60 - 70 ° C (the plating solution is added with magnesium sulfate).

It is to be understood that the decorative plating layer according to the present invention preferably further comprises an undercoat layer disposed between the workpiece and the cobalt plating layer or the cobalt-iron alloy plating layer to increase the adhesion of the workpiece to the cobalt plating layer or the cobalt-iron alloy plating layer, and increase Coating surface gloss. When the surface of the workpiece is made of a copper alloy, the underplating layer comprises a pre-plated copper layer and a copper sulfate layer. When the surface of the workpiece is made of white iron or stainless steel, the underplating layer is a pre-plated nickel layer. When the surface of the workpiece is a zinc or zinc alloy, the underplating layer includes an alkaline copper plating layer and a copper pyrophosphate plating layer. When the workpiece is made of aluminum, aluminum alloy or tantalum alloy, the workpiece must be first treated with immersion and chemical nickel. When the workpiece is β-titanium, pure titanium or titanium alloy, the underplating layer is a pre-nickel layer or a pre-plated layer.

In addition, when the surface of the workpiece is made of non-metal, such as: ABS, a chemical nickel layer is first formed on the surface of the workpiece, and then the cobalt plating or cobalt-iron alloy plating is applied, and then the color or baking varnish is applied. When the thickness of the cobalt plating layer or the alloy plating layer of the present invention is 2 μ η or more, although the workpiece material is copper nickel or copper-iron alloy having a nickel content of 30-40% or the surface of the workpiece has a chemical nickel layer, the cobalt of the present invention The coating or alloy coating has good coverage and porosity. The nickel release can be less than 0.05 parts per million according to EN1811 - EN12412, which can achieve the definition of nickel-free products. This product can supply special body to allergic to nickel. Consumers use it, there will be no allergies. Therefore, the present invention is very suitable for use in protective decorative plating, for example, for glasses frames, watches, earrings, rings, necklaces and the like, mobile phone cases, mobile phone accessories or other products that are in contact with the skin of the face to ensure Consumer health.

The results of the comparison of the thickness, hardness, nickel release amount, anti-tarnishing ability, salt spray test and artificial sweat test with the conventional nickel plating layer and the copper-tin alloy plating layer of the cobalt plating layer or alloy plating layer according to the present invention are shown in Table 2 below. Table 2 (The data source of this table is the workpiece of copper alloy)

It can be seen from Table 2 that the thickness of the nickel plating layer, the cobalt plating layer and the alloy plating layer can be greater than 2 μ η, but the copper-tin alloy plating layer cannot be formed to a thickness greater than 2 μ πι. The hardness of nickel plating is 500 - 550HV, the hardness of cobalt coating is 450 - 500HV, the hardness of alloy coating is 400 - 500HV, the hardness of copper-tin alloy coating is the highest, 550 - 650HV; the release of nickel is determined by EN1811 - EN12412 The results show that the nickel release of nickel coating is much larger than 0.05ppm, the nickel release of cobalt coating and alloy coating is less than 0.05ppm, the nickel release of copper-tin alloy coating is more than 0.05ppm; in terms of anti-tarnishing ability, nickel coating and cobalt The coating is the worst, the cobalt-iron alloy plating layer formed by the plating solution without adding magnesium sulfate and the copper-tin alloy plating layer, electricity The cobalt-iron-magnesium alloy plating layer formed by adding magnesium sulfate to the plating solution has the best anti-tarnishing ability.

Example

The cobalt plating or alloy plating according to the present invention is formed by the following process. First, a plating solution is added to the plating bath (see Tables 3 to 5 below for composition and concentration). Next, the workpiece is immersed in the plating solution of the plating bath as a cathode, and a cobalt plate having a purity of more than 99% (for forming a cobalt plating layer or an alloy plating layer) or a cobalt iron alloy sheet having an iron content of about 2 - 5% (for The plating solution in which the plating bath is immersed in the formation of an alloy plating layer serves as an anode. Finally, a direct current is applied between the anode and the cathode. The workpiece is preferably at least 7 cm away from the anode to ensure uniformity of the coating. The power supply used selects the appropriate size DC rectifier depending on the surface area of the workpiece. The current density of the plating layer and the temperature inside the plating bath are shown in Tables 3 to 5 below. The outside of the anode must be covered with a PP braid to prevent defects such as electric rough. Cobalt coating

Table 4 Cobalt-iron lr coating (no barium sulfate added to the plating solution)

Table 5 Cobalt-iron-magnesium alloy coating (with magnesium sulfate added to the plating solution)

The cobalt plating solution and the cobalt iron plating solution according to the present invention are all free of cyanide, so that not only the sewage treatment cost is low, but also the health of the plating process worker can be effectively ensured. Therefore, the decorative coating according to the present invention not only satisfies the needs of consumers, but also has an environmentally conscious process. The decorative coating according to the present invention has a nickel release amount of less than 0.05 ppm, so that the finished product can be supplied to consumers who are allergic to nickel with a special constitution, and there is no allergic reaction.

While the invention has been described in terms of the foregoing preferred embodiments, it is not intended to Therefore, the scope of protection of the present invention should be defined by the patent claims.

Claims

Rights request

A decorative coating comprising a cobalt coating formed on a surface of the member, the cobalt coating comprising at least 99% cobalt by weight and up to 1% of unavoidable impurities; and a color plating layer formed thereon On the cobalt plating layer, the color coating layer is selected from the group consisting of tin-cobalt-grey steel plating, palladium plating, gold plating, ruthenium plating, gold-palladium-copper alloy plating, white chrome plating, and black chrome plating.

2. The decorative coating according to claim 1, wherein: the surface of the workpiece is made of a copper alloy, and the decorative coating further comprises a pre-plated copper layer and a copper sulfate layer disposed between the workpiece and the cobalt plating layer.

3. The decorative coating according to claim 1, wherein: when the surface of the workpiece is made of β-titanium, pure titanium or titanium alloy, the decorative coating further comprises a pre-nickel layer or a pre-gold plating layer. Between the workpiece and the cobalt coating.

4. The decorative coating according to claim 1, wherein: when the surface of the workpiece is non-metallic, the decorative coating further comprises an electroless nickel layer disposed between the workpiece and the cobalt plating layer.

A decorative coating characterized in that it comprises an alloy coating formed on the surface of the workpiece, the alloy coating comprising 95 - 98% cobalt, 2 - 5% iron and unavoidable impurities by weight.

6. The decorative coating according to claim 5, further comprising: a color plating layer formed on the alloy plating layer, the surface color coating layer is coated with tin-cobalt gray steel, palladium plating layer, gold plating layer, ruthenium plating layer, gold palladium Selected from the group consisting of copper alloy plating, white chrome plating, and black chrome plating.

The decorative coating according to claim 5, wherein the surface of the workpiece is made of a copper alloy, and the decorative coating further comprises a pre-plated copper layer and a copper sulfate layer disposed between the workpiece and the alloy plating layer.

The decorative coating according to claim 5, wherein: when the surface of the workpiece is made of β-titanium, pure titanium or titanium alloy, the decorative coating further comprises a pre-nickel layer or a pre-gold plating layer. Between the workpiece and the alloy plating.

9. The decorative coating according to claim 5, wherein: when the surface of the workpiece is non-metallic, the decorative coating further comprises an electroless nickel layer disposed between the workpiece and the alloy plating.

10. The decorative coating according to claim 5, wherein: the alloy plating layer further comprises 0.05 - 0.2% magnesium.

11. A plating bath for forming a cobalt coating, characterized in that it comprises:

250 - 300g/l of CoS0 ₄ · 7H ₂ 0;

30 - 60 g / l of sodium chloride;

30 - 40 g / l of boric acid;

0.1 - 0.5g / l of Class I additives; 5 - 10g / l of Class II additives;

The type I additive is an organic compound containing C=0, C=C, C=N, N=N or N=0 unsaturated bond, and the type II additive contains C=C—C—S0 ₂ , C=C— S0 ₂ — or C ≡ C—C—S0 ₂ — an organic compound of the structure; wherein the pH of the plating solution is not more than 4.

12. The plating solution for forming a cobalt plating layer according to claim 11, wherein: the class I additive is a group consisting of trichloroethanol, coumarin butanediol, acridine and quinine. Selected; the Group II additive is selected from the group consisting of saccharin, naphthalenesulfonic acid, and sulfonamide.

13. A plating solution for forming a cobalt-iron alloy plating layer, characterized in that it comprises: 250 - 300 g/l of CoS0 ₄ · 7H ₂ 0;

1-lOg/l of FeS0 ₄ · 7H ₂ 0;

40 - 60g / l of sodium chloride;

35-55 g/l boric acid;

0.2 - 0.5g / l of Class I additives;

4 - 8g / l of Class II additives;

Wherein the type I additive is an organic compound containing a C=0, CK, C=N, N=N or N=0 unsaturated bond, and the type II additive contains C=C—C—S0 ₂ , OC—S0 ₂ — or (≡ C—C—S0 ₂ — an organic compound of the structure; wherein the pH of the plating solution is not more than 4.

A plating solution for forming a cobalt-iron alloy plating layer according to claim 13, wherein: said class I additive is in a group consisting of trichloroethanol, coumarin butanediol, acridine and quinine. Selected; the Class II additive is selected from the group consisting of saccharin, fulvic acid, and acesulfame.

15. A plating solution for forming a cobalt-iron-magnesium alloy plating layer, characterized in that it comprises: 240 - 280 g/l of CoS0 ₄ · 7H ₂ 0;

1 - 8g/l of FeS0 ₄ · 7H ₂ 0;

0.5 - 2g / l of MgS0 ₄ · 7H ₂ 0;

50 - 70g / l of sodium chloride;

40 - 60 g / l of boric acid;

0.1 - 0.3g / l of Class I additives;

5 - 10g / l of Class II additives;

Wherein the type I additive is an organic compound containing a C=0, OC, C=NN=N or N=0 unsaturated bond, and the type II additive contains C=C—C—S0 ₂ , C=C—S0 ₂ — or C≡ C—C—S0 ₂ — an organic compound of the structure; wherein the pH of the plating solution is not more than 4.

A plating solution for forming a cobalt-iron-magnesium alloy plating layer according to claim 15, wherein: the class I additive is composed of trichloroethanol, coumarin butanediol, acridine and quinine. Selected from the group; the class II additive is selected from the group consisting of saccharin, naphthalene sulfonic acid, and p-xanthine.

A method of forming a cobalt plating layer, comprising the steps of: adding a plating for forming a cobalt plating layer according to claim 11 to an electroplating bath; Liquid

Immersing a cobalt plate in the plating solution of the plating bath as an anode;

Immersing a workpiece in a plating solution of the plating bath as a cathode;

Direct current is passed between the anode and the cathode;

The current density is controlled at 3 - 5ASD, and the temperature in the plating bath is controlled at 50 - 60 °C.

18. A method of forming a cobalt-iron alloy coating, characterized in that it comprises the steps of: adding a plating solution for forming a cobalt-iron alloy plating layer according to claim 13 to an electroplating bath;

a cobalt plate or a cobalt iron alloy plate is used as an anode, and is immersed in the plating solution of the plating tank, wherein the cobalt-iron alloy plate has an iron content of about 2 - 5 % _;

Immersing a workpiece in a plating solution of the plating bath as a cathode;

Direct current is passed between the anode and the cathode;

The current density is controlled at 2 - 5ASD, and the temperature in the plating bath is controlled at 50 - 60 °C.

19. A method of forming a cobalt-iron-magnesium alloy coating, characterized in that it comprises the following steps:

Adding a plating solution for forming a cobalt iron magnesium alloy plating layer according to claim 15 to the plating tank;

A cobalt plate or a cobalt iron alloy plate is immersed in the plating solution of the plating tank as an anode, and the iron content of the cobalt iron alloy plate is about 2 - 5 % _;

Immersing a workpiece in a plating solution of the plating bath as a cathode;

Direct current is passed between the anode and the cathode;

The current density is controlled at 1.5 - 5ASD, and the temperature in the plating bath is controlled at 50 - 60 °C.

20. A product for applying a decorative coating, characterized in that it comprises:

a workpiece

A decorative plating layer is formed on the surface of the workpiece, the decorative plating layer comprises a cobalt plating layer or an alloy plating layer, wherein the cobalt plating layer comprises at least 99% cobalt and at most 1% of unavoidable impurities by weight, the alloy plating layer is by weight Contains 95 - 98% cobalt, 2-4 % iron and unavoidable impurities.

The decorative plating product according to claim 20, wherein: the workpiece surface material is a copper alloy, and the decorative plating layer further comprises a pre-plated copper layer and a copper sulfate layer disposed on the workpiece and the cobalt plating layer or Between the cobalt-iron alloy layers.

22. The decorative plating product according to claim 20, wherein: the workpiece material is a copper-nickel or copper-iron alloy having a nickel content of up to 30-40%, and the cobalt plating layer or the cobalt-iron alloy layer has a thickness of at least 2 μ ηι.

The decorative plating product according to claim 20, wherein: when the surface of the workpiece is made of β-titanium, pure titanium or titanium alloy, the decorative coating further comprises a pre-nickel layer or a pre-plated layer. Between the workpiece and the cobalt or cobalt-iron alloy layer.

The decorative plating product according to claim 20, wherein: when the surface material of the workpiece is non-metal, the decorative plating layer further comprises a chemical nickel layer disposed on the workpiece And between the cobalt plating layer or the cobalt iron alloy layer.

The decorative plating product according to claim 20, further comprising: a color plating layer formed on the cobalt plating layer or the cobalt iron alloy layer, wherein the color coating layer is made of tin-cobalt gray copper plating layer, palladium plating layer, Selected from the group consisting of gold plating, ruthenium plating, gold-palladium-copper alloy plating, white chrome plating, and black chrome plating.

26. The decorative plating product according to claim 20, wherein: the workpiece is selected from the group consisting of a spectacle frame, a watch, an earring, a ring, a necklace, a cell phone button, a mobile phone case, and a mobile phone accessory. .

27. A decorative plating product according to claim 20, wherein: said alloy coating further comprises 0.05 - 0.2% magnesium.