Method for improving chemical nickel plating rate and corrosion resistance

Abstract

The invention discloses a chemical nickel plating method, and belongs to the technical field of nickel plating method.The chemical nickel plating method comprises the following steps that S1, a workpiece to be plated is put into a chemical nickel plating solution to be subjected to chemical nickel plating, and a plated workpiece with a primary plating layer is obtained; and S2, a cathode is added into the chemical nickel plating solution in the step S1, a plating workpiece with a primary plating layer serves as an anode, electrification is conducted, the anode current density is controlled to be smaller than 0.5 A / dm < 2 >, the electrification time is smaller than 40 s, and the chemical nickel plating process is completed. By adopting the chemical nickel-plating method, the chemical nickel-plating rate can be obviously improved under the action of the anode current, and the corrosion resistance of the obtained chemical nickel-plating layer is obviously enhanced.

Description

Technical Field

[0001] The invention belongs to the field of nickel plating methods, and more specifically, relates to a method for improving chemical nickel plating rate and corrosion resistance. Background Art

[0002] Chemical nickel plating technology has become an important technical choice in the manufacture of many industrial and consumer products because of its good corrosion resistance, good all-plating ability and ability to enhance the hardness and wear resistance of the substrate. However, the deposition rate of nickel in the current industrial application of chemical nickel plating technology is relatively low, and with the development of modern science and technology, people's requirements for new materials are getting higher and higher. Further improving the corrosion resistance of nickel coatings has become a research focus of nickel plating. In the prior art, the deposition rate of chemical nickel plating can be accelerated and the corrosion resistance of the nickel layer can be improved by adding different types of organic or inorganic additives, but the addition of additives is prone to various side effects, such as high nickel plating temperature, difficult process control, high energy consumption, poor plating solution stability, easy volatility, short service life, etc.

[0003] In order to increase the rate of chemical nickel plating, patent CN201710730006.8 proposes to use an accelerator to accelerate the nickel plating rate, but the ferrous sulfate used will pollute the chemical nickel plating solution, which is irritating and not environmentally friendly, and the plating temperature needs to be 90°C, which consumes a lot of energy, and the nickel plating solution is volatile. Patent CN201911334558.2 proposes to use organic acids, amino acid accelerators, sodium fluoride and ammonium chloride to increase the rate of chemical nickel plating, but too many additives will pollute the nickel plating solution, and it is difficult to master the appropriate compounding ratio and pH of the nickel plating solution.

[0004] In order to improve the corrosion resistance of the chemical nickel layer, patent CN202310818483.5 proposes to use a chemical nickel plating solution and a combined stabilizer to improve the corrosion resistance of the chemical nickel plating layer, wherein the combined stabilizer includes modified binaphthylthiourea, chromium sulfate and thiodipropionic acid, but the preparation process of modified binaphthylthiourea is complicated, and the substances such as chloroform and dichloromethane used in the preparation process are toxic and not environmentally friendly. Patent CN202410633397.1 proposes to use a composite complexing agent, iodate and rare earth compound to improve the corrosion resistance of the chemical nickel plating layer, but the plating temperature needs to be 85-90°C, which consumes a lot of energy and the nickel plating solution is volatile. Summary of the invention

[0005] In order to solve the above-mentioned defects of the prior art, the object of the present invention is to provide a method for improving the rate and corrosion resistance of chemical nickel plating.

[0006] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0007] A chemical nickel plating method comprises the following steps:

[0008] S1. The workpiece to be plated is placed in a chemical nickel plating solution for chemical nickel plating to obtain a plated workpiece having a primary coating;

[0009] S2. Add a cathode to the chemical nickel plating solution of step S1, use the workpiece with the primary coating as the anode, turn on the power, and control the anode current density to <0.5A / dm 2 , power-on time is less than 40s, and the chemical nickel plating process is completed.

[0010] The present invention performs chemical nickel plating on a workpiece to be plated so that a nickel plating layer is formed on the workpiece to be plated, and then uses the workpiece to be plated as an anode connected to the positive electrode of a power source, uses an inert electrode or a nickel electrode as a cathode, and continues to perform chemical nickel plating after current is passed. Within a selected current density and power-on time, the rate of chemical nickel plating and the corrosion resistance of the chemical nickel plating layer are significantly improved.

[0011] Furthermore, in step S2, the anode current density is controlled to be 0.1-0.3 A / dm 2 .

[0012] Furthermore, the power-on time in step S2 is 5 to 35 seconds.

[0013] Furthermore, the cathode in step S2 is an inert electrode or a nickel electrode, and preferably, the inert electrode is a platinum electrode.

[0014] In the present invention, the conditions for chemical nickel plating in step S1 can refer to the prior art.

[0015] Furthermore, the time for chemical nickel plating in step S1 is 5 to 60 minutes.

[0016] Furthermore, the temperature of the chemical nickel plating in step S1 is 70-75°C.

[0017] Furthermore, the pH value of the chemical nickel plating solution in step S1 is 4.5-5.0.

[0018] Furthermore, the pH value of the chemical nickel plating solution in step S1 can be adjusted by adding acid or alkali, such as dilute sulfuric acid, sodium hydroxide, ammonia water, etc.

[0019] Furthermore, the chemical nickel plating solution in step S1 includes nickel salt, reducing agent, complexing agent, stabilizer components, and further, may also include accelerator, wetting agent and other components.

[0020] Furthermore, the nickel salt is one or more of nickel sulfate, nickel chloride, nickel acetate, and nickel carbonate.

[0021] Furthermore, the reducing agent of the chemical nickel plating solution in step S1 is sodium hypophosphite and / or sodium hypophosphite.

[0022] In some embodiments of the present invention, the composition of the chemical nickel plating solution is: NiSO4·6H2O18~25g / L, NaH2PO2·H2O 15~25g / L, sodium succinate 5~15g / L, malic acid 5~15g / L, CH3COONa 15g / L, lactic acid 5~15mL / L, lead acetate 0.5~1.5mg / L, and the solvent is deionized water.

[0023] In step S1, the workpiece to be plated is pre-treated before chemical nickel plating, including degreasing, micro-etching, and activation steps. The degreasing, micro-etching, and activation steps can be performed with reference to the prior art.

[0024] Furthermore, the degreasing is to place the workpiece to be plated in a degreasing liquid at a temperature of 50° C. and soak it for 1 to 10 minutes, and then take out the workpiece to be plated and wash it with water.

[0025] Furthermore, the degreasing liquid comprises the following components: NaOH 5-10 g / L, NaCO3 5-15 g / L, Na3PO4 15-25 g / L, and the solvent is deionized water.

[0026] Furthermore, the micro-etching is to immerse the workpiece to be plated in a micro-etching solution for 1 to 2 minutes, and then take out the workpiece to be plated and wash it with water.

[0027] Furthermore, the micro-etching solution includes the following components: Na2S2O8 25-35 g / L, concentrated sulfuric acid 50-100 mL / L, and the solvent is deionized water.

[0028] Furthermore, the activation is to place the workpiece to be plated into the activation solution and soak it for 1 to 2 minutes, and then take out the workpiece to be plated and wash it with water.

[0029] Furthermore, the activation solution comprises the following components: PdCl2 0.1-0.5 g / L, NH4Cl 0.5-2.0 g / L, and the solvent is deionized water.

[0030] Furthermore, the workpiece to be plated used in the present invention is a copper sheet.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention forms a primary nickel coating by chemically plating nickel on a workpiece to be plated, and then uses the workpiece to be plated as an anode to pass an anode current, controls the anode current density and the power-on time, and continues to perform chemical nickel plating. Under the action of the anode current, the deposition rate of the chemical nickel plating and the corrosion resistance of the coating can be significantly improved, and the process is performed at a relatively low temperature, which is beneficial to maintaining the stability of the plating solution. The present invention has a simple process, no additional additives, low cost, and is suitable for industrial production. DETAILED DESCRIPTION

[0033] The content of the present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present embodiment are conventional reagents, methods and equipment in the art.

[0034] The components of the degreasing solution used in the following examples include 5 g / L of sodium hydroxide, 10 g / L of sodium carbonate, and 20 g / L of trisodium phosphate, and the solvent is deionized water; the components of the micro-etching solution include 30 g / L of sodium persulfate and 50 mL / L of 98% concentrated sulfuric acid, and the solvent is deionized water; the components of the activation solution include 0.1 g / L of palladium chloride and 1 g / L of ammonium chloride, and the solvent is deionized water.

[0035] The workpiece to be plated used in the following embodiments is a 2cm×2cm copper sheet. The pretreatment steps performed before chemical nickel plating on the workpiece to be plated are: placing the copper sheet in the above-mentioned degreasing solution and soaking it at a temperature of 50°C for 1 min, and after washing with water, the copper sheet is placed in the above-mentioned micro-etching solution and soaked for 1 min. After washing with water, the copper sheet is placed in the above-mentioned activation solution and soaked for 1 min. Washing with water obtains the copper sheet to be plated used in each embodiment and comparative example.

[0036] The components of the chemical nickel plating solution used in the following examples include NiSO4·6H2O 20g / L, NaH2PO2·H2O 25g / L, sodium succinate 10g / L, sodium acetate 15g / L, malic acid 5g / L, lactic acid 8mL / L, lead acetate 0.8mg / L, and the solvent is deionized water. The solution is prepared according to the above formula, and then the pH value is adjusted to 4.8 to obtain the chemical nickel plating solution.

[0037] Example 1

[0038] A chemical nickel plating method comprises the following steps: placing a copper sheet to be plated in a chemical nickel plating solution at 75°C for 20 minutes without removing the copper sheet, using a platinum electrode as a cathode and the copper sheet as an anode to apply an anodic current, and controlling the anodic current density to be 0.25A / dm 2 The power-on time is 10s, followed by water washing and drying to obtain a nickel coating.

[0039] Example 2

[0040] A chemical nickel plating method comprises the following steps: placing a copper sheet to be plated in a chemical nickel plating solution at 75°C for 20 minutes without removing the copper sheet, using a platinum electrode as a cathode and the copper sheet as an anode to apply an anodic current, and controlling the anodic current density to be 0.25A / dm 2 The power-on time is 20s, followed by water washing and drying to obtain a nickel coating.

[0041] Example 3

[0042] A chemical nickel plating method comprises the following steps: placing a copper sheet to be plated in a chemical nickel plating solution at 75°C for 20 minutes without removing the copper sheet, using a platinum electrode as a cathode and the copper sheet as an anode to apply an anodic current, and controlling the anodic current density to be 0.25A / dm 2 The power-on time is 30s, followed by water washing and drying to obtain a nickel coating.

[0043] Example 4

[0044] A chemical nickel plating method comprises the following steps: placing a copper sheet to be plated in a chemical nickel plating solution at 75°C for 5 minutes without removing the copper sheet, using a platinum electrode as a cathode and the copper sheet as an anode to apply an anodic current, and controlling the anodic current density to be 0.25A / dm 2 The power-on time is 10s, followed by water washing and drying to obtain a nickel coating.

[0045] Example 5

[0046] A chemical nickel plating method comprises the following steps: placing a copper sheet to be plated in a chemical nickel plating solution at 75°C for 5 minutes without removing the copper sheet, using a platinum electrode as a cathode and the copper sheet as an anode to apply an anodic current, and controlling the anodic current density to be 0.25A / dm 2 The power-on time is 30s, followed by water washing and drying to obtain a nickel coating.

[0047] Comparative Example 1

[0048] The copper sheet to be plated is placed in a chemical nickel plating solution and plated at 75° C. for 20 minutes and 30 seconds, followed by water washing and drying to obtain a nickel plating layer.

[0049] Comparative Example 2

[0050] The copper sheet to be plated was placed in a chemical nickel plating solution at 75°C for 20 minutes without removing the copper sheet. The platinum electrode was used as the cathode and the copper sheet was used as the anode to apply an anodic current. The anodic current density was controlled to be 0.25A / dm 2 The power-on time is 40s, followed by water washing and drying to obtain a nickel coating.

[0051] Comparative Example 3

[0052] The copper sheet to be plated was placed in a chemical nickel plating solution at 75°C for 20 minutes without removing the copper sheet. The platinum electrode was used as the cathode and the copper sheet was used as the anode to apply an anodic current. The anodic current density was controlled to be 0.5A / dm 2 The power-on time is 30s, followed by water washing and drying to obtain a nickel coating.

[0053] Performance Testing

[0054] Plating thickness test: The nickel plating obtained in the embodiment and the comparative example was measured using a thickness gauge, and the results are shown in Table 1.

[0055] Test of corrosion resistance of coating: A nitric acid solution with a nitric acid: water ratio of 1:2 (volume ratio concentration) was dropped onto the surface of the nickel coating obtained in the embodiment and the comparative example, and the time when bubbles began to appear on the surface of the coating (i.e., corrosion began) was recorded. The test results are shown in Table 2.

[0056] Table 1

[0057]

[0058] Table 2

[0059]

[0060] It can be seen from the data in Table 1 that, in the present invention, after a nickel coating is formed on the workpiece to be plated, the introduction of an anodic current can promote the deposition rate of chemical nickel plating and increase the thickness of the nickel coating; from the data of Example 3 and Comparative Examples 2 and 3, it can be seen that an excessively large anodic current density or an excessively long power-on time is not conducive to improving the deposition rate of chemical nickel plating.

[0061] From the data in Table 2, it can be seen that the present invention can enhance the corrosion resistance of the chemical nickel plating layer by passing the anodic current after the nickel plating layer is formed on the workpiece to be plated; from the data of Example 3 and Comparative Examples 2 and 3, it can be seen that too large an anodic current density or too long a current-on time is not conducive to improving the corrosion resistance of the chemical nickel plating layer. The chemical nickel plating method of the present invention is simple to operate, does not require additional additives, and has good application prospects.

[0062] The above embodiments are preferred experimental methods of the present invention, but the implementation methods of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A chemical nickel plating method, characterized in that: The following steps are involved: S1. The workpiece to be plated is placed in a chemical nickel plating solution for chemical nickel plating to obtain a plated workpiece having a primary coating; S2. Add a cathode to the chemical nickel plating solution of step S1, use the workpiece with the primary coating as the anode, turn on the power, and control the anode current density to <0.5A / dm 2 , power-on time is less than 40s, and the chemical nickel plating process is completed.

2. The chemical nickel plating method according to claim 1, characterized in that: In step S2, the anode current density is controlled to be 0.1-0.3 A / dm 2 .

3. The chemical nickel plating method according to claim 1, characterized in that: The power-on time in step S2 is 5 to 35 seconds.

4. The chemical nickel plating method according to claim 1, characterized in that: In the step S2, the cathode is an inert electrode or a nickel electrode.

5. The chemical nickel plating method according to claim 1, characterized in that: The time for chemical nickel plating in step S1 is 5 to 60 minutes.

6. The chemical nickel plating method according to claim 1, characterized in that: The temperature of the chemical nickel plating in step S1 is 70-75°C.

7. The chemical nickel plating method according to claim 1, characterized in that: The pH value of the chemical nickel plating solution in step S1 is 4.5-5.

0.

8. The chemical nickel plating method according to claim 1, characterized in that: The chemical nickel plating solution in step S1 includes nickel salt, reducing agent, complexing agent and stabilizer components.

9. The chemical nickel plating method according to claim 8, characterized in that: The nickel salt is one or more of nickel sulfate, nickel chloride, nickel acetate and nickel carbonate.

10. The chemical nickel plating method according to claim 8, characterized in that: The reducing agent is sodium hypophosphite and / or sodium hypophosphite.

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