Copper-based nickel stripping solution and application thereof

Abstract

The invention provides a copper-based nickel stripping solution and application thereof, and belongs to the technical field of chemical stripping, the copper-based nickel stripping solution comprises the following raw materials by weight per unit volume: 0-60 g / L of sulfuric acid, 15-60 g / L of an oxidant, 1-3 g / L of an oxidant activator, 0.1-4 g / L of a surfactant, 0.3-15 g / L of a corrosion inhibitor, 0.5-21 g / L of a cosolvent, 5-150 g / L of a complexing agent, and the balance of water; the oxidant is persulfate or hydrogen peroxide, and the oxidant activator is a porous carbon material. The copper-based nickel stripping liquid is good in stripping effect and free of damage to a base material, the use amount of an oxidizing agent can be reduced, and the cost is further reduced.

Description

Technical Field

[0001] The invention relates to a stripping agent, in particular to a copper-based nickel stripping solution, and belongs to the technical field of chemical stripping. Background Art

[0002] With economic development, the problem of metal corrosion has become increasingly serious. Metal surface coating technology is an effective anti-corrosion method. However, even with the most advanced technology, some substandard plated parts are inevitable during production. Scrapping these substandard plated parts directly affects the company's economic benefits and also results in a waste of resources.

[0003] In traditional nickel stripping processes, many use cyanide and nitric acid methods, which are highly toxic in operation. Therefore, it is necessary to explore environmentally friendly nickel stripping solutions. Summary of the Invention

[0004] In view of the above problems, the present invention provides a copper-based nickel stripping solution and its application, which are used to improve the nickel stripping effect of copper-based materials.

[0005] To achieve the above objectives, the technical solution of the present invention is: a copper-based nickel stripping solution, which includes the following types of raw materials, by unit volume weight: 0-60g / L sulfuric acid, 15-60g / L oxidant, 1-3g / L oxidant activator, 0.1-4g / L surfactant, 0.3-15g / L corrosion inhibitor, 0.5-21g / L cosolvent, 5-150g / L complexing agent, and the balance is water; the oxidant is persulfate or hydrogen peroxide, and the oxidant activator is a porous carbon material.

[0006] Furthermore, the persulfate is any one of sodium persulfate, potassium persulfate, ammonium persulfate, and potassium peroxymonosulfate composite salt, or a combination of several of them.

[0007] Furthermore, the surfactant is any one of alkylphenol polyoxyethylene ether X-100, OP-10, X-405, fatty alcohol polyoxyethylene ether AES, PEH-6, sodium lauryl sulfate, and sodium lauryl sulfonate.

[0008] Furthermore, the corrosion inhibitor is any one of BTA, TTA, and 2-ethylbenzimidazole.

[0009] Furthermore, the cosolvent is any one of polyethylene glycol 200, glycerol, and isopropyl alcohol.

[0010] Furthermore, the complexing agent is at least one of sodium gluconate, organic phosphine, citric acid monohydrate, and glycine.

[0011] Furthermore, the porous carbon material is prepared by the following steps:

[0012] Step S1, taking a predetermined amount of sodium citrate and calcium chloride, respectively, adding them to water, and stirring them until dissolved, to obtain a sodium citrate solution and a calcium chloride solution;

[0013] Step S2, mixing the sodium citrate solution and the calcium chloride solution, heating and placing in a constant temperature water bath for a predetermined time;

[0014] Step S3, centrifuging to obtain a precipitate, and drying the precipitate;

[0015] Step S4, carbonizing the dried precipitate;

[0016] Step S5, soaking the carbonized product in dilute hydrochloric acid to remove impurities, and then washing with water until neutral;

[0017] Step S6: drying the washed product to obtain a porous carbon material.

[0018] Furthermore, the porous carbon material is prepared by the following steps:

[0019] Step S1: add 18-19 g of sodium citrate and 10-11 g of calcium chloride to 500 ml of water, respectively, and stir until dissolved to obtain a sodium citrate solution and a calcium chloride solution;

[0020] Step S2, mixing the sodium citrate solution and the calcium chloride solution, heating to 75-80° C. and placing in a constant temperature water bath for 10-15 minutes;

[0021] Step S3, centrifuging to obtain a precipitate, and placing the precipitate in a freeze dryer for drying for 24 hours;

[0022] Step S4, placing the dried precipitate in a horizontal tube furnace for carbonization within a temperature range, heating the temperature from room temperature to 700°C at a heating rate of 5°C / min under an argon atmosphere, and keeping the temperature for 2 hours;

[0023] Step S5, soaking the carbonized product in dilute hydrochloric acid to remove impurities, and then washing with water until neutral;

[0024] Step S6: drying the washed product in a vacuum drying oven at 120° C. for 12 hours to obtain a porous carbon material.

[0025] The copper-based nickel stripping liquid is used for stripping nickel on the surface of copper-based plated materials.

[0026] Furthermore, the copper-based nickel stripping liquid is used for copper-based stripping treatment according to the following steps: first, concentrated sulfuric acid is diluted, and then an oxidant and an oxidant activator are added and stirred until dissolved to obtain an intermediate liquid, and then a surfactant, a corrosion inhibitor, a cosolvent and a complexing agent are mixed to obtain a mixed liquid, and the mixed liquid is added to the intermediate liquid and stirred until the solution is uniform, and the volume is fixed, and finally, the copper-based plated parts are placed therein for stripping treatment.

[0027] The beneficial effects of the copper-based nickel stripping solution of the present invention and its application are as follows:

[0028] The copper-based nickel stripping solution of the present invention has good stripping effect, does not damage the substrate, and can reduce the amount of oxidant used, thereby further reducing costs.

[0029] In the present invention, the oxidant is the main component of the stripping solution that corrodes the coating. The addition of the oxidant activator activates the oxidant, so that the persulfate is activated to generate sulfate radicals, thereby enhancing the corrosiveness to the coating and improving the stripping efficiency. Simultaneously, due to the improved effect of the activated oxidant, the amount of the oxidant can be further reduced, thereby reducing the stripping cost. The oxidant activator can also enhance the corrosive effect of hydrogen peroxide on the coating.

[0030] The surfactant of the present invention increases the corrosion inhibition effect of the corrosion inhibitor and stabilizes the solution; the cosolvent increases the dissolution amount of the corrosion inhibitor and has a synergistic effect on corrosion inhibition due to the formation of a liquid film.

[0031] The complexing agent of the present invention can improve the stripping speed to a certain extent and improve the utilization rate of the oxidant by complexing nickel ions. The oxidant activator of the present invention is prepared by carbonizing calcium citrate. A certain amount of citric acid component may remain in the final product, which can synergistically act with the complexing agent to chelate nickel in the nickel stripping solution. In addition, since the oxidant activator has a porous structure, it has a certain adsorption effect on flocs formed after citric acid chelates nickel, which can further promote the corrosion of the nickel layer by the oxidant, thereby improving the stripping efficiency. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely below. Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0033] A copper-based nickel stripping solution comprises the following raw materials by weight per unit volume: 0-60g / L sulfuric acid, 15-60g / L oxidant, 1-3g / L oxidant activator, 0.1-4g / L surfactant, 0.3-15g / L corrosion inhibitor, 0.5-21g / L cosolvent, 5-150g / L complexing agent, and the balance is water; the oxidant is persulfate or hydrogen peroxide, and the oxidant activator is a porous carbon material. Preferably,

[0034] The persulfate is any one of sodium persulfate, potassium persulfate, ammonium persulfate, and potassium monopersulfate complex salt, or a combination thereof; the surfactant is any one of alkylphenol polyoxyethylene ether X-100, OP-10, X-405, fatty alcohol polyoxyethylene ether AES, PEH-6, sodium lauryl sulfate, and sodium lauryl sulfonate; the corrosion inhibitor is any one of BTA, TTA, and 2-ethylbenzimidazole; the cosolvent is any one of polyethylene glycol 200, glycerol, and isopropyl alcohol; and the complexing agent is at least one of sodium gluconate, organic phosphine, citric acid monohydrate, and glycine.

[0035] Further preferably, the porous carbon material is prepared by the following steps:

[0036] Step S1: add 18-19 g of sodium citrate and 10-11 g of calcium chloride to 500 ml of water, respectively, and stir until dissolved to obtain a sodium citrate solution and a calcium chloride solution;

[0037] Step S2, mixing the sodium citrate solution and the calcium chloride solution, heating to 75-80° C. and placing in a constant temperature water bath for 10-15 minutes;

[0038] Step S3, centrifuging to obtain a precipitate, and placing the precipitate in a freeze dryer for drying for 24 hours;

[0039] Step S4, placing the dried precipitate in a horizontal tube furnace for carbonization within a temperature range, heating the temperature from room temperature to 700°C at a heating rate of 5°C / min under an argon atmosphere, and keeping the temperature for 2 hours;

[0040] Step S5, soaking the carbonized product in dilute hydrochloric acid to remove impurities, and then washing with water until neutral;

[0041] Step S6: drying the washed product in a vacuum drying oven at 120° C. for 12 hours to obtain a porous carbon material.

[0042] The copper-based nickel stripping solution is used to strip the nickel on the surface of a copper-based plated material. Preferably, the copper-based nickel stripping solution is used for stripping the nickel on the surface of a copper-based plated material according to the following steps:

[0043] First, dilute concentrated sulfuric acid, then add the oxidant and the oxidant activator and stir until dissolved to obtain an intermediate liquid (in a clear and transparent state, the temperature of the dissolution process after the oxidant and the oxidant activator are added should not be higher than 50°C), then mix the surfactant, corrosion inhibitor, co-solvent and complexing agent to obtain a mixed solution (if white precipitate appears before weighing, it may be due to the precipitation of the material due to low temperature storage. The components can be heated to 60°C in a water bath to dissolve the precipitate before weighing), add the mixed solution to the intermediate liquid and stir until the solution is uniform (a colorless and transparent liquid), adjust the volume, and finally place the copper-based plated parts in it for stripping treatment.

[0044] When diluting concentrated sulfuric acid, add four-fifths of deionized water to the stripping container. Slowly add the weighed concentrated sulfuric acid to the deionized water in the stripping container. Be sure to stir continuously during the addition process. Note that the sulfuric acid dilution process releases a lot of heat and the temperature should be controlled below 60°C.

[0045] Example 1

[0046] A copper-based nickel stripping solution comprises the following raw materials: 5 g / L sulfuric acid, 60 g / L sodium persulfate, 1 g / L oxidant activator, 1 g / L surfactant, 15 g / L BTA, 1 g / L polyethylene glycol 200, 100 g / L citric acid monohydrate, and the balance is water; the oxidant activator is a porous carbon material prepared by the above steps.

[0047] According to the preparation method of the copper-based nickel stripping solution, the raw materials in Example 1 were prepared into a copper-based nickel stripping solution for stripping. The specific stripping conditions and stripping results are as follows:

[0048] Stripping conditions: 25℃, hanging stripping;

[0049] Copper is stripped to 2 microns of nickel;

[0050] Nickel stripping rate: 0.1μm / min, no corrosion to copper base, nickel stripping amount 7g / L, after nickel stripping, the surface is smooth with metallic luster, no color difference, and can be directly electroplated.

[0051] Among them, the nickel stripping rate is calculated according to the following formula:

[0052]

[0053] In the above formula, the unit of nickel stripping rate is μm / min.

[0054] M0 is the weight of the plated part before stripping, in g;

[0055] M1 is the weight of the plated part after stripping, in g;

[0056] ρ is the density of nickel, specifically 8.9 g / cm 3 ;

[0057] S is the surface area of the piece to be stripped, in cm 2 ;

[0058] T is the stripping time, in min.

[0059] The nickel stripping rate can also be calculated according to the following formula:

[0060]

[0061] In the above formula, the unit of nickel stripping rate is μm / min.

[0062] L0 is the thickness of the plated part before stripping, in mm;

[0063] L1 is the thickness of the plated part after stripping, in mm;

[0064] T is the stripping time, in min;

[0065] The 2 in the formula means that the plated part has two surfaces that need to be stripped.

[0066] The amount of nickel stripping is determined by continuously processing the stripped parts until they meet the standards, and then the total amount of nickel plating stripped is measured, that is, the quality difference between the stripped parts before and after stripping.

[0067] The appearance smoothness and color difference after nickel stripping are observed by visual inspection.

[0068] The detection methods in other embodiments are the same as that in this embodiment.

[0069] Example 2

[0070] A copper-based nickel stripping solution comprises the following raw materials: 20 g / L sulfuric acid, 15 g / L potassium persulfate, 2 g / L oxidant activator, 4 g / L fatty alcohol polyoxyethylene ether (AES), 5 g / L TTA, 20 g / L glycerol, 150 g / L sodium gluconate, and the balance is water; the oxidant activator is a porous carbon material prepared by the above steps.

[0071] According to the preparation method of the copper-based nickel stripping solution, the raw materials in Example 2 were prepared into a copper-based nickel stripping solution for stripping. The specific stripping conditions and stripping results are as follows:

[0072] Stripping conditions: 55℃, hanging stripping.

[0073] Brass back 5 micron nickel plating

[0074] Nickel stripping rate: 0.2μm / min, no corrosion to copper base, nickel stripping amount 8g / L, after nickel stripping, the surface is smooth with metallic luster, no color difference, and can be directly electroplated.

[0075] Example 3

[0076] A copper-based nickel stripping solution comprises the following raw materials: 60 g / L sulfuric acid, 30 g / L hydrogen peroxide, 3 g / L oxidant activator, 0.5 g / L sodium dodecylsulfonate, 0.5 g / L 2-ethylbenzimidazole, 10 g / L isopropyl alcohol, 5 g / L glycine, and the balance is water; the oxidant activator is a porous carbon material prepared by the above steps.

[0077] According to the preparation method of the copper-based nickel stripping solution, the raw materials in Example 2 were prepared into a copper-based nickel stripping solution for stripping. The specific stripping conditions and stripping results are as follows:

[0078] Stripping conditions: 45℃, hanging stripping.

[0079] Copper is stripped to 5 microns of chemical nickel.

[0080] Nickel stripping rate: 0.3μm / min, no corrosion to copper base, nickel stripping amount 9g / L, after nickel stripping, the surface is smooth with metallic luster, no color difference, and can be directly electroplated.

[0081] Comparative Example 1

[0082] Comparative Example 1 is carried out on the basis of Example 1, except that no oxidant activator is added to the copper-based nickel stripping solution in Comparative Example 1, and the rest is the same as Example 1.

[0083] According to the preparation method of the copper-based nickel stripping solution, the raw materials in Comparative Example 1 were prepared into a copper-based nickel stripping solution for stripping. The specific stripping conditions and stripping results are as follows:

[0084] Stripping conditions: 25℃, hanging stripping;

[0085] Copper is stripped to 2 microns of nickel;

[0086] Nickel stripping rate: 0.05μm / min, no corrosion to copper base, nickel stripping amount 7g / L, after nickel stripping, the surface is smooth with metallic luster, no color difference, and can be directly electroplated.

[0087] Comparative Example 2

[0088] Comparative Example 2 was carried out on the basis of Example 1, except that the amount of the oxidant activator added in Comparative Example 2 was 0.5 g / L, and the rest was the same as Example 1.

[0089] According to the preparation method of the copper-based nickel stripping solution, the raw materials in Comparative Example 2 were prepared into a copper-based nickel stripping solution for stripping. The specific stripping conditions and stripping results are as follows:

[0090] Stripping conditions: 25℃, hanging stripping;

[0091] Copper is stripped to 2 microns of nickel;

[0092] Nickel stripping rate: 0.07μm / min, no corrosion to copper base, nickel stripping amount 7g / L, after nickel stripping, the surface is smooth with metallic luster, no color difference, and can be directly electroplated.

[0093] Comparative Example 3

[0094] Comparative Example 3 was carried out on the basis of Example 1, except that the amount of the oxidant activator added in Comparative Example 3 was 4 g / L, and the rest was the same as Example 1.

[0095] According to the preparation method of the copper-based nickel stripping solution, the raw materials in Comparative Example 3 were prepared into a copper-based nickel stripping solution for stripping. The specific stripping conditions and stripping results are as follows:

[0096] Stripping conditions: 25℃, hanging stripping;

[0097] Copper is stripped to 2 microns of nickel;

[0098] Nickel stripping rate: 0.1μm / min, no corrosion to copper base, nickel stripping amount 8g / L, after nickel stripping, the surface is smooth with metallic luster, no color difference, and can be directly electroplated.

[0099] Comparative Example 4

[0100] Comparative Example 4 was carried out on the basis of Example 1, except that the amount of co-solvent added in Comparative Example 4 was 0.3 g / L, and the rest was the same as Example 1.

[0101] According to the preparation method of the copper-based nickel stripping solution, the raw materials in Comparative Example 4 were prepared into a copper-based nickel stripping solution for stripping. The specific stripping conditions and stripping results are as follows:

[0102] Stripping conditions: 25℃, hanging stripping;

[0103] Copper is stripped to 2 microns of nickel;

[0104] Nickel stripping rate: 0.1μm / min, no corrosion to copper base, nickel stripping amount 7g / L, unevenness after nickel stripping (with bumps), metallic luster without bumps, no color difference, further polishing is required before direct electroplating.

[0105] Comparative Example 5

[0106] Comparative Example 5 is carried out on the basis of Example 1, except that the amount of complexing agent added in Comparative Example 5 is 4 g / L, and the rest is the same as Example 1.

[0107] According to the preparation method of the copper-based nickel stripping solution, the raw materials in Example 1 were prepared into a copper-based nickel stripping solution for stripping. The specific stripping conditions and stripping results are as follows:

[0108] Stripping conditions: 25℃, hanging stripping;

[0109] Copper is stripped to 2 microns of nickel;

[0110] Nickel stripping rate: 0.9μm / min, no corrosion to copper base, nickel stripping amount 6g / L, after nickel stripping, the surface is smooth with metallic luster, no color difference, and can be directly electroplated.

[0111] Comparative Example 6

[0112] Comparative Example 6 is carried out on the basis of Example 1, except that no oxidant activator is added in Comparative Example 6, but the amount of oxidant is increased to 150 g / L, and the rest is the same as Example 1.

[0113] According to the preparation method of the copper-based nickel stripping solution, the raw materials in Comparative Example 6 were prepared into a copper-based nickel stripping solution for stripping. The specific stripping conditions and stripping results are as follows:

[0114] Stripping conditions: 25℃, hanging stripping;

[0115] Copper is stripped to 2 microns of nickel;

[0116] Nickel stripping rate: 0.1μm / min, no corrosion to copper base, nickel stripping amount 7g / L, after nickel stripping, the surface is smooth with metallic luster, no color difference, and can be directly electroplated.

[0117] Comparative Example 7

[0118] Comparative Example 7 is carried out on the basis of Example 1, except that the oxidant activator in Comparative Example 7 uses the same amount of activated carbon, and the rest is the same as Example 1.

[0119] According to the preparation method of the copper-based nickel stripping solution, the raw materials in Comparative Example 7 were prepared into a copper-based nickel stripping solution for stripping. The specific stripping conditions and stripping results are as follows:

[0120] Stripping conditions: 25℃, hanging stripping;

[0121] Copper is stripped to 2 microns of nickel;

[0122] Nickel stripping rate: 0.04μm / min, no corrosion to copper base, nickel stripping amount 6g / L, after nickel stripping, the surface is smooth with metallic luster, no color difference, and can be directly electroplated.

[0123] The copper base of the present invention includes red copper and brass, and the coating includes chemically plated low-phosphorus nickel and electroplated nickel. The coating thickness is 2-10 microns, the electroplated nickel is generally 2-5 microns, and the chemical nickel is 3-10 microns.

[0124] The nickel stripping rate of the invention is 0.1-0.3 μm / min, has no corrosion to the copper base, and the nickel stripping amount is 7-10 g / L. After nickel stripping, the surface is flat, has metallic luster, has no color difference, and can be directly electroplated.

[0125] The copper-based nickel stripping solution of the present invention can be used for stripping by hanging or rolling. Hanging stripping involves hanging the stripped parts on a hanger and placing them in a stripping tank for stripping. Rolling stripping involves placing the stripped parts in a drum, immersing the drum in the stripping solution, and rotating the drum for stripping.

[0126] Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

Claims

1. A copper-based nickel stripping solution, characterized in that: The invention comprises the following raw materials by weight per unit volume: 0-60 g / L sulfuric acid, 15-60 g / L oxidant, 1-3 g / L oxidant activator, 0.1-4 g / L surfactant, 0.3-15 g / L corrosion inhibitor, 0.5-21 g / L co-solvent, 5-150 g / L complexing agent, and the balance is water; the oxidant is persulfate or hydrogen peroxide, and the oxidant activator is a porous carbon material.

2. A copper-based nickel stripping solution according to claim 1, characterized in that The persulfate is any one of sodium persulfate, potassium persulfate, ammonium persulfate, and potassium peroxymonosulfate composite salt, or a combination of several of them.

3. A copper-based nickel stripping solution according to claim 1, characterized in that The surfactant is any one of alkylphenol polyoxyethylene ether X-100, OP-10, X-405, fatty alcohol polyoxyethylene ether AES, PEH-6, sodium lauryl sulfate, and sodium lauryl sulfonate.

4. A copper-based nickel stripping solution according to claim 1, characterized in that The corrosion inhibitor is any one of BTA, TTA, and 2-ethylbenzimidazole.

5. A copper-based nickel stripping solution according to claim 1, characterized in that The cosolvent is any one of polyethylene glycol 200, glycerol, and isopropyl alcohol.

6. A copper-based nickel stripping solution according to claim 1, characterized in that The complexing agent is at least one of sodium gluconate, organic phosphine, citric acid monohydrate and glycine.

7. A copper-based nickel stripping solution according to claim 1, characterized in that The porous carbon material is prepared by the following steps: Step S1, taking a predetermined amount of sodium citrate and calcium chloride, respectively, adding them to water, and stirring them until dissolved, to obtain a sodium citrate solution and a calcium chloride solution; Step S2, mixing the sodium citrate solution and the calcium chloride solution, heating and placing in a constant temperature water bath for a predetermined time; Step S3, centrifuging to obtain a precipitate, and drying the precipitate; Step S4, carbonizing the dried precipitate; Step S5, soaking the carbonized product in dilute hydrochloric acid to remove impurities, and then washing with water until neutral; Step S6: drying the washed product to obtain a porous carbon material.

8. A copper-based nickel stripping solution according to claim 7, characterized in that: The porous carbon material is prepared by the following steps: Step S1: add 18-19 g of sodium citrate and 10-11 g of calcium chloride to 500 ml of water, respectively, and stir until dissolved to obtain a sodium citrate solution and a calcium chloride solution; Step S2, mixing the sodium citrate solution and the calcium chloride solution, heating to 75-80° C. and placing in a constant temperature water bath for 10-15 minutes; Step S3, centrifuging to obtain a precipitate, and placing the precipitate in a freeze dryer for drying for 24 hours; Step S4, placing the dried precipitate in a horizontal tube furnace for carbonization within a temperature range, heating the temperature from room temperature to 700°C at a heating rate of 5°C / min under an argon atmosphere, and keeping the temperature for 2 hours; Step S5, soaking the carbonized product in dilute hydrochloric acid to remove impurities, and then washing with water until neutral; Step S6: drying the washed product in a vacuum drying oven at 120° C. for 12 hours to obtain a porous carbon material.

9. The use of the copper-based nickel stripping solution according to any one of claims 1 to 8, characterized in that: The copper-based nickel stripping solution is used to strip the nickel on the surface of a copper-based plated material.

10. The use according to claim 9, characterized in that The copper-based nickel stripping solution is used for copper-based stripping treatment according to the following steps: first, concentrated sulfuric acid is diluted, then an oxidant and an oxidant activator are added and stirred until dissolved to obtain an intermediate solution, then a surfactant, a corrosion inhibitor, a cosolvent and a complexing agent are mixed to obtain a mixed solution, the mixed solution is added to the intermediate solution and stirred until the solution is uniform, the volume is fixed, and finally, the copper-based plated parts are placed therein for stripping treatment.

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