An environmentally friendly nickel stripping agent

Abstract

The invention relates to an environmentally friendly nickel stripping agent, which mainly solves the problem that the nickel stripping agent in the prior art uses concentrated nitric acid or a strong oxidant such as concentrated nitric acid, which easily causes damage to a metal substrate, or generates toxic and harmful gases such as sulfur dioxide or nitrogen oxides, and is unfriendly to the atmospheric environment. The environmentally friendly nickel stripping agent is used, which comprises, by weight: 8 parts of a nickel oxidizing agent; 0.4 to 24 parts of a base metal corrosion inhibitor; and 4 to 16 parts of a nickel complexing agent. The technical solution that the nickel oxidizing agent comprises a nitrobenzene sulfonic acid compound solves the technical problem well, and can be used in the production of the nickel stripping agent.

Description

Technical Field

[0001] The invention relates to an environmentally friendly nickel stripping agent and application thereof. Background Art

[0002] With the development of modern science and technology, metal nickel plating has been widely used as a mature process technology. Because metal nickel has high chemical stability, it can be used as a protective decorative coating on the surface of steel, zinc die castings, aluminum alloys and copper alloys to protect the base material from corrosion or play a bright decorative role; it is also often used as an intermediate coating for other coatings, on which a thin layer of chromium or a layer of imitation gold is plated, which has better corrosion resistance and a more beautiful appearance. In terms of functional applications, nickel plating about 1 to 3 mm thick on parts in special industries can achieve the purpose of repair. In particular, it is increasingly widely used in continuous casting crystallizers, molds on the surface of electronic components, alloy die-casting molds, complex-shaped aerospace engine parts, and the manufacture of microelectronic components.

[0003] At present, there are three main types of products that need nickel stripping, namely, unqualified nickel-plated products produced in continuous process and large-scale production, nickel-plated workpieces that need to be recycled after use, and metal parts that need to remove the nickel layer at a fixed point. Commonly used nickel stripping methods are divided into electrolytic method and chemical method. Electrolytic nickel stripping requires an external dedicated power supply, which is too expensive and is generally rarely considered. The chemical method can be further divided into acid stripping and alkaline stripping. Acid stripping requires the use of reagents such as concentrated sulfuric acid or concentrated nitric acid, which is extremely damaging to the metal substrate and may produce toxic gases. Alkaline stripping is relatively mild, and it uses the oxide film on the surface of nickel to form a complex with ammonia to dissolve.

[0004] Existing nickel stripping technologies either contain strong acids that damage the substrate and produce toxic gases, or contain solvents that are not very environmentally friendly. Summary of the invention

[0005] The present invention aims to solve the problem that the nickel stripping agent in the prior art uses concentrated nitric acid or a strong oxidant such as concentrated nitric acid, which easily causes damage to the metal substrate, or produces toxic and harmful gases such as sulfur dioxide or nitrogen oxides, which are not friendly to the atmospheric environment. A new nickel stripping agent is provided, which avoids damage to the metal substrate, has mild performance, and is friendly to the atmospheric environment.

[0006] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0007] An environmentally friendly nickel stripping agent, comprising, by weight:

[0008] Nickel oxidant, 8 parts;

[0009] Base metal corrosion inhibitor, 0.4 to 24 parts;

[0010] Nickel complexing agent, 4 to 16 parts;

[0011] The nickel oxidizing agent includes a nitrobenzene sulfonic acid compound.

[0012] Since the oxidant uses nitrobenzene sulfonic acid compounds instead of concentrated nitric acid or other oxidants such as concentrated nitric acid, it avoids damage to the metal substrate, has mild performance, and also avoids the production of toxic and harmful gases such as sulfur dioxide or nitrogen oxides. It is a nickel stripping agent that is friendly to the atmospheric environment.

[0013] In the above technical solution, the nitrobenzenesulfonic acid compound refers to a compound that can ionize into anions as shown in Formula 1 in water:

[0014]

[0015] It should be noted that all nitrobenzene sulfonic acid compounds are measured to provide the same amount of sodium nitrobenzene sulfonate required for the anion. For example, whether the nitrobenzene sulfonic acid compound is nitrobenzene sulfonic acid or a salt of nitrobenzene sulfonic acid, it is measured to provide the same amount of sodium nitrobenzene sulfonate required for the anion.

[0016] In the above technical scheme, as a non-limiting example, the substrate metal corrosion inhibitor can be 0.6 parts, 0.8 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts and the like.

[0017] In the above technical solution, as a non-limiting example, the nickel complexing agent can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.

[0018] In the above technical solution, the nitro compound preferably includes a first nitrobenzene sulfonic acid compound and a second nitrobenzene sulfonic acid compound, the first nitrobenzene sulfonic acid compound is a m-nitrobenzene sulfonic acid compound, and the second nitrobenzene sulfonic acid compound is selected from an o-nitrobenzene sulfonic acid compound or a p-nitrobenzene sulfonic acid compound. The first nitrobenzene sulfonic acid compound and the second nitrobenzene sulfonic acid compound have a mutual synergistic effect in improving the nickel stripping rate.

[0019] In the above technical scheme, the mutual ratio between the second nitro compound and the first nitro compound is not particularly limited, and the two have comparable synergistic effects in improving the nickel stripping rate. Preferably, the molar ratio of the second nitro compound to the first nitro compound is greater than 0 and less than 0.1, for example but not limited to the molar ratio of the second nitro compound to the first nitro compound is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, etc.

[0020] In the above technical solution, the nitrobenzenesulfonic acid compound is preferably nitrobenzenesulfonic acid or a salt of nitrobenzenesulfonic acid.

[0021] In the above technical solutions, those skilled in the art can reasonably select corrosion inhibitors that are effective for the substrate metal according to the substrate metal used for nickel plating, and can achieve comparable technical effects without having to make creative efforts.

[0022] Just as an example, in a specific embodiment of the present invention, an experiment on a base metal corrosion inhibitor was conducted with a base metal of steel as the object.

[0023] In the above technical solution, the substrate metal corrosion inhibitor is at least one alcoholamine selected from the group consisting of monoethanolamine, diethanolamine and triethanolamine.

[0024] Alcoholamines can exist in the form of free alcoholamine molecules or in the form of cations (such as salts with acids) after the alcoholamines absorb protons. Due to the different pH values ​​of the system, the two forms are usually present in different proportions. According to the practice in the art, all these forms of alcoholamines are converted into the form of free alcoholamine molecules. For example, monoethanolamine can exist in the form of free monoethanolamine molecules, or in the form of cations formed after absorbing protons (such as forming monoethanolamine salts with acids). According to the practice in the art, all these forms of monoethanolamine are converted to be measured in the form of free monoethanolamine molecules; diethanolamine can exist in the form of free diethanolamine molecules, or in the form of cations formed after absorbing protons (such as forming diethanolamine salts with acids). According to the practice in the art, all these forms of diethanolamine are converted to be measured in the form of free diethanolamine molecules; triethanolamine can exist in the form of free triethanolamine molecules, or in the form of cations formed after absorbing protons (such as forming triethanolamine salts with acids). According to the practice in the art, all these forms of triethanolamine are converted to be measured in the form of free triethanolamine molecules.

[0025] In the above technical solution, it is preferred that the substrate metal corrosion inhibitor includes both monoethanolamine and triethanolamine; in this case, monoethanolamine and triethanolamine have a mutually promoting effect in reducing the amount of substrate metal corrosion.

[0026] In the above technical solution, the ratio between triethanolamine and monoethanolamine is not particularly limited, and both have comparable mutual promotion effects in reducing the amount of metal corrosion of the substrate. Preferably, the weight ratio of triethanolamine to monoethanolamine is greater than 0 and less than 0.1, for example but not limited to the weight ratio of triethanolamine to monoethanolamine is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, etc.

[0027] In the above technical solution, the nickel complexing agent is preferably selected from citric acid, salts of citric acid, gluconic acid, salts of gluconic acid, and aminocarboxylic acid complexing agents; the aminocarboxylic acid complexing agent is selected from at least one of the material group consisting of glycine, glutamic acid, ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid and their salts. For comparison only, the nickel complexing agent in the specific embodiment of the present invention is tetrasodium ethylenediaminetetraacetic acid.

[0028] As a non-limiting example, the nickel complexing agent is selected from citric acid, citric acid salts, gluconic acid, gluconic acid salts, and aminocarboxylic acid complexing agents; the aminocarboxylic acid complexing agent is selected from at least one of the substance group consisting of glycine, glutamic acid, ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid and their salts.

[0029] When nickel complexing agents exist in the form of acid, salt, or even salt in various acid salt and normal salt forms, they are all converted to the form in the acid form. For example, citric acid can exist in the form of free citric acid molecules or citrate (including various acid salts and normal salts). All these forms of citric acid are converted to the form in the free citric acid molecule form.

[0030] Gluconic acid can exist in the form of free gluconic acid molecules or in the form of gluconate (including various acid salts and normal salts), and all these forms of gluconic acid are converted into the form of free gluconic acid molecules.

[0031] The aminocarboxylic acid complexing agent can exist in the form of a free aminocarboxylic acid complexing agent acid molecule or a salt (including various acid salts and normal salts) of the aminocarboxylic acid complexing agent. All forms of the aminocarboxylic acid complexing agent are converted to the form of the free aminocarboxylic acid complexing agent. For example, free glycine and its salt are converted to the form of free glycine; free glutamic acid and its salt (including acid salts and normal salts) are converted to the form of free glycine; free ethylenediaminetetraacetic acid and its salt (including various acid salts and normal salts) are converted to the form of free ethylenediaminetetraacetic acid.

[0032] In the above technical solution, the nickel stripping agent is preferably alkaline. It is further preferably dissolved in water to a weight concentration of 8% based on sodium nitrobenzene sulfonate and a pH of 8 to 12 measured at 25°C, for example but not limited to 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9 and the like.

[0033] In the above technical solution, the nickel stripping agent preferably includes 0.05 to 5 parts of a stabilizer. The stabilizer is more preferably a reducing agent, which is used to prevent the pH of the nickel stripping agent working solution from decreasing as the nickel stripping proceeds, thereby preventing corrosion of the metal substrate of the nickel-plated workpiece and preventing corrosion of the substrate metal.

[0034] In the above technical solution, as non-limiting examples, the stabilizer is 0.10 parts, 0.15 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, etc.

[0035] In the above technical solution, preferably, the stabilizer includes a salt of sulfite or a salt of thiosulfate.

[0036] In the above technical scheme, those skilled in the art can reasonably select the stabilizer without creative work and can achieve the effect of the stabilizer. For comparison only, the stabilizer in the embodiments of the present invention and the comparative examples is sodium sulfite.

[0037] In the above technical solution, the nickel stripping agent preferably includes 0.05 to 5 parts of a surfactant. The use of a surfactant can improve the wettability of the coating surface, increase the reaction area, and also reduce the activation energy of the interface reaction and increase the reaction rate; in addition, the surfactant is conducive to the dispersion of the nickel metal chelate product after the reaction, avoiding aggregation on the workpiece surface and preventing the reaction from continuing.

[0038] In the above technical scheme, as non-limiting examples, the surfactant is 0.10 parts, 0.15 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts and the like.

[0039] In the above technical solution, the surfactant is preferably an anionic surfactant.

[0040] In the above technical solution, the anionic surfactant is preferably at least one selected from the group consisting of salts of alkylbenzene sulfonic acid, salts of alkyl sulfate, salts of fatty alcohol polyoxyethylene sulfate and salts of α-olefin sulfonic acid.

[0041] In the above technical scheme, those skilled in the art can reasonably select a specific surfactant and can expect the surfactant to have an effect. For comparison only, the surfactant in the embodiments of the present invention and the comparative examples is sodium lauryl sulfate.

[0042] The salt is not particularly limited and can be an alkali metal salt, an organic base salt (for example, but not limited to, ammonia, monoethanolamine, diethanolamine, triethanolamine, etc., salts obtained by neutralizing an organic base containing a nitrogen atom in the molecule with a corresponding acid), and the alkali metal is preferably K or Na.

[0043] As a non-limiting example, the salt of m-nitrobenzenesulfonic acid may be sodium m-nitrobenzoate or potassium m-nitrobenzoate, and the like.

[0044] As a non-limiting example, the salt of o-nitrobenzenesulfonic acid may be sodium o-nitrobenzoate or potassium o-nitrobenzoate, and the like.

[0045] As a non-limiting example, the salt of p-nitrobenzenesulfonic acid may be sodium p-nitrobenzoate or potassium p-nitrobenzoate, and the like.

[0046] As a non-limiting example, the salt of citric acid can be an acid salt or a normal salt obtained by neutralizing 1 to 3 protons in the three protons in the citric acid molecule by sodium hydroxide and / or sodium hydroxide, such as monosodium citrate, monopotassium citrate, monopotassium citrate, dipotassium citrate, tripotassium citrate, potassium sodium hydrogen citrate, potassium sodium citrate, and the like.

[0047] By way of non-limiting example, the salt of gluconic acid may be sodium gluconate or potassium gluconate.

[0048] By way of non-limiting example, the salt of glycine may be sodium glycinate or potassium glycinate.

[0049] As a non-limiting example, the salt of glutamic acid may be an acid salt of glutamic acid (such as monosodium glutamate or monopotassium glutamate) or a normal salt of glutamic acid (such as disodium glutamate or dipotassium glutamate).

[0050] As a non-limiting example, the salt of EDTA may be an acid salt (eg, disodium EDTA, tetrasodium EDTA, or tetrapotassium EDTA).

[0051] By way of non-limiting example, the salt of sulfurous acid may be sodium sulfite or potassium sulfite.

[0052] By way of non-limiting example, the salt of thiosulfate may be sodium thiosulfate or potassium thiosulfate.

[0053] As a non-limiting example, the salt of alkylbenzene sulfonic acid may be sodium alkylbenzene sulfonate or potassium alkylbenzene sulfonate.

[0054] By way of non-limiting example, the salt of alkyl sulfate may be sodium alkyl sulfate or potassium alkyl sulfate.

[0055] As a non-limiting example, the salt of fatty alcohol polyoxyethylene sulfate may be sodium fatty alcohol polyoxyethylene sulfate or potassium fatty alcohol polyoxyethylene sulfate.

[0056] As a non-limiting example, the salt of alpha olefin sulfonic acid may be sodium alpha olefin sulfonate or potassium alpha olefin sulfonate.

[0057] In the above technical scheme, the nickel stripping agent preferably includes 0.05 to 5 parts of a defoaming agent. The use of a defoaming agent prevents vibration during cleaning or the heating of the solution to produce air bubbles that adhere to the surface of the workpiece, resulting in uneven and incomplete stripping. When a surfactant is used, it can also prevent the surfactant from generating a large amount of foam during cleaning and causing overflow. There is no special restriction on the selection of a specific defoaming agent. Those skilled in the art can reasonably choose it without having to make creative efforts and can achieve comparable results. Just as a comparison, in the specific embodiment of the present invention, the defoaming agent uses the RQ-421 silicone defoaming agent provided by Rongqiang Technology Co., Ltd.

[0058] In the above technical solution, as a non-limiting example, the defoaming agent is 0.10 parts, 0.15 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts and the like.

[0059] In the above technical solution, the defoamer can be selected from at least one of the group consisting of fatty acid ester defoamers, amide defoamers, phosphate defoamers, silicone defoamers, polyether defoamers and polyether-modified polysiloxane defoamers.

[0060] As a non-limiting example, the defoaming agent is one of the defoaming agents selected from the group consisting of fatty acid esters, amides, phosphates, silicones, polyethers, and polyether-modified polysiloxanes.

[0061] There is no particular limitation on the preparation of the nickel stripping agent described in the present invention. Those skilled in the art can mix the required components, or use a solvent (such as water) to prepare the nickel stripping agent into a liquid form. The liquid form can be higher than the concentration of the nickel stripping agent working solution at the nickel stripping production site and diluted to the required concentration at the nickel stripping production site, or it can be directly prepared into the concentration of the nickel stripping agent working solution at the nickel stripping production site.

[0062] The technical key of the present invention is the selection of the nickel stripping agent components. Once the composition of the nickel stripping agent is determined, the preparation method of the nickel stripping agent itself is not particularly limited. Those skilled in the art can reasonably select the mixing order according to the required components to achieve comparable technical effects without having to pay creative labor.

[0063] The second technical problem to be solved by the present invention is the application of the above-mentioned nickel stripping agent.

[0064] To solve the second of the above technical problems, the technical solution of the present invention is as follows:

[0065] Application of the nickel stripping agent described in any one of the above technical solutions in nickel stripping.

[0066] The technical key of the present invention is the selection of nickel stripping agent components and component dosages. As for the specific use of the nickel stripping agent, those skilled in the art can reasonably determine it without having to make creative efforts.

[0067] The third technical problem to be solved by the present invention is to provide a method for stripping nickel.

[0068] To solve the third of the above technical problems, the technical solution of the present invention is as follows:

[0069] The method for stripping nickel comprises the following steps:

[0070] (1) obtaining a nickel stripping agent working solution containing the nickel stripping agent described in any one of the above technical solutions;

[0071] (2) contacting the nickel-plated workpiece to be stripped of nickel with the nickel stripping agent working solution to convert the nickel plating layer into a black substance to obtain a semi-finished nickel stripped workpiece;

[0072] (3) The semi-finished nickel-stripped workpiece is brought into contact with a cleaning solution, and the black matter is removed from the surface of the semi-finished nickel-stripped workpiece by means of physical force.

[0073] In the above technical solution, preferably, the weight concentration of the nickel stripping agent working solution in step (1) is 4-12% in terms of sodium nitrobenzene sulfonate; for example, but not limited to, the weight concentration is 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, etc. For the sake of comparison, the weight concentration of the nickel stripping agent working solution in step (1) in the embodiment of the present invention and the comparative example is 8% in terms of sodium nitrobenzene sulfonate.

[0074] In the above technical scheme, preferably, the pH of the nickel stripping agent working solution in step (1) is 8 to 12, for example, but not limited to the pH of the nickel stripping agent working solution is, for example, but not limited to, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, etc.; more preferably, the pH is 8 to 10. For comparison purposes, the pH of the nickel stripping agent working solution in step (1) of the embodiments of the present invention and the comparative examples is 9.0.

[0075] In the above technical solution, preferably, the solvent of the nickel stripping agent working solution in step (1) is preferably water or preferably mainly water, and the meaning of mainly water is that the weight content of water in the solvent is 60-100%; for example, but not limited to, the weight content of water in the solvent is 65%, 70%, 75%, 80%, 85%, 90%, 95%, etc. For the convenience of comparison, the solvents of the embodiments and comparative examples of the present invention are all water.

[0076] In the above technical solution, the contact described in step (2) is, for example but not limited to, immersing the nickel-plated workpiece to be stripped into a nickel stripping agent working liquid, or spraying the nickel-plated workpiece to be stripped with the nickel stripping agent working liquid.

[0077] In the above technical scheme, the contact temperature of step (2) is preferably above 40°C and below the boiling point of the nickel stripping agent working solution. For example, but not limited to, the temperature is 45°C, 50°C, 55°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, 93°C, 94°C, etc., more preferably 50-95°C, more preferably 60-90°C.

[0078] In the above technical scheme, as for the contact time required for the contact described in step (2), or the time required for the nickel coating to be converted into a black substance, those skilled in the art can reasonably grasp it, but as a general principle, the greater the thickness of the nickel coating of the nickel-plated workpiece to be stripped, the lower the concentration of the nickel stripping agent working solution, the lower the contact temperature, and the longer the required contact time. Conversely, the smaller the thickness of the nickel coating of the nickel-plated workpiece to be stripped, the higher the concentration of the nickel stripping agent working solution, the higher the contact temperature, and the shorter the required contact time.

[0079] In the above technical scheme, there is no particular limitation on the way of providing the physical force in step (3), and those skilled in the art can reasonably choose it without creative work. For example, it can be wiping, ultrasound, etc. The cleaning liquid can be a pure solvent, such as clean water, or a washing surfactant and a washing auxiliary agent commonly used in the art. For ease of comparison, the embodiments and comparative examples in the specific embodiments of the present invention all use clean water as the cleaning liquid and ultrasound as the way of providing the physical force.

[0080] In the present specification, when the required components exist or can exist in the form of crystalline hydrates, they are measured in the form without crystal water.

[0081] In the present invention, when the required pH value of the nickel stripping agent (or the nickel stripping agent working solution) is adopted, those skilled in the art know to add an acidic regulator or an alkaline regulator to the nickel stripping agent (or the nickel stripping agent working solution). As for when to use the acidic regulator and when to use the alkaline regulator, as for which substances to use as the acidic regulator and which substances to use as the alkaline regulator, those skilled in the art can all reasonably choose without having to make creative efforts and can all achieve comparable technical effects of the present invention.

[0082] Evaluation of the Corrosiveness of Nickel Stripping Agents

[0083] Use nickel stripping agent working solution as the test solution and follow the test method specified in Section 5.9 (Corrosiveness) of GB / T35759-2017 (Metal Cleaning Agents).

[0084] Evaluation of nickel stripping rate of nickel stripping agent

[0085] Except for using a nickel sheet (specifications: 30mm×10mm×1.5mm, with a small hole of 2mm in diameter in the middle of the narrow side 2.5mm away from the narrow side), and immersing the nickel sheet in the test solution for 1 hour instead of 2 hours, the rest of the operations are the same as those for evaluating the corrosion of the nickel stripping agent.

[0086] The nickel stripping rate is calculated according to the following formula:

[0087] V=10000×(W1-W2) / (ρ×S×t)

[0088] Where: V─nickel stripping rate, μm / h;

[0089] ρ─Nickel density, g / cm 3 ;

[0090] W1─Nickel sheet mass before reaction, g;

[0091] W2─mass of nickel sheet after reaction, g;

[0092] S─ Area of ​​nickel sheet, cm 2 ;

[0093] t─reaction time, h.

[0094] The present invention is described in detail below through specific implementation modes. DETAILED DESCRIPTION

[0095] [Example 1]

[0096] 1. Nickel stripping agent formula

[0097] Sodium m-nitrobenzene sulfonate, 8.0 parts;

[0098] Monoethanolamine, 1.6 parts;

[0099] EDTA-4Na, (calculated as EDTA), 8.0 parts;

[0100] Na2SO3, 0.4 parts;

[0101] Sodium lauryl sulfate, 0.8 part;

[0102] Defoaming agent, 0.8 parts.

[0103] 2. Preparation of nickel stripping agent working solution

[0104] (1) Take 70 parts of water, add 8.0 parts of sodium m-nitrobenzene sulfonate, 1.6 parts of monoethanolamine, and 8.0 parts of EDTA-4Na (calculated as EDTA), and stir to dissolve;

[0105] (2) Add 0.4 parts of Na2SO3 and stir to dissolve;

[0106] (3) adding 0.8 parts of sodium lauryl sulfate and 0.8 parts of defoamer and stirring to dissolve;

[0107] (4) Add water to 100 parts and stir evenly;

[0108] (5) Use a small amount of 10% by weight sulfuric acid aqueous solution to adjust the pH of the working solution to 9.0.

[0109] 3. Nickel stripping rate and corrosion evaluation

[0110] The above nickel stripping agent working solution was used as a test solution to evaluate the corrosion of the nickel stripping agent and the nickel stripping rate of the nickel stripping agent.

[0111] For ease of comparison, the nickel stripping agent formula is listed in Table 1, the corrosion evaluation is listed in Table 2, and the nickel stripping rate is listed in Table 3.

[0112] [Example 2]

[0113] 1. Nickel stripping agent formula

[0114] Sodium o-nitrobenzenesulfonate, 8.0 parts;

[0115] Monoethanolamine, 1.6 parts;

[0116] EDTA-4Na, (calculated as EDTA), 8.0 parts;

[0117] Na2SO3, 0.4 parts;

[0118] Sodium lauryl sulfate, 0.8 part;

[0119] Defoaming agent, 0.8 parts.

[0120] 2. Preparation of nickel stripping agent working solution

[0121] (1) Take 70 parts of water, add 8.0 parts of sodium o-nitrobenzene sulfonate, 1.6 parts of monoethanolamine, and 8.0 parts of EDTA-4Na (calculated as EDTA), and stir to dissolve;

[0122] (2) Add 0.4 parts of Na2SO3 and stir to dissolve;

[0123] (3) adding 0.8 parts of sodium lauryl sulfate and 0.8 parts of defoamer and stirring to dissolve;

[0124] (4) Add water to 100 parts and stir evenly;

[0125] (5) Use a small amount of 10% by weight sulfuric acid aqueous solution to adjust the pH of the working solution to 9.0.

[0126] 3. Nickel stripping rate and corrosion evaluation

[0127] The above nickel stripping agent working solution was used as a test solution to evaluate the corrosion of the nickel stripping agent and the nickel stripping rate of the nickel stripping agent.

[0128] For ease of comparison, the nickel stripping agent formula is listed in Table 1, the corrosion evaluation is listed in Table 2, and the nickel stripping rate is listed in Table 3.

[0129] [Example 3]

[0130] 1. Nickel stripping agent formula

[0131] Sodium p-nitrobenzenesulfonate, 8.0 parts;

[0132] Monoethanolamine, 1.6 parts;

[0133] EDTA-4Na, (calculated as EDTA), 8.0 parts;

[0134] Na2SO3, 0.4 parts;

[0135] Sodium lauryl sulfate, 0.8 part;

[0136] Defoaming agent, 0.8 parts.

[0137] 2. Preparation of nickel stripping agent working solution

[0138] (1) Take 70 parts of water, add 8.0 parts of sodium p-nitrobenzenesulfonate, 1.6 parts of monoethanolamine, and 8.0 parts of EDTA-4Na (calculated as EDTA), and stir to dissolve;

[0139] (2) Add 0.4 parts of Na2SO3 and stir to dissolve;

[0140] (3) adding 0.8 parts of sodium lauryl sulfate and 0.8 parts of defoamer and stirring to dissolve;

[0141] (4) Add water to 100 parts and stir evenly;

[0142] (5) Use a small amount of 10% by weight sulfuric acid aqueous solution to adjust the pH of the working solution to 9.0.

[0143] 3. Nickel stripping rate and corrosion evaluation

[0144] The above nickel stripping agent working solution was used as a test solution to evaluate the corrosion of the nickel stripping agent and the nickel stripping rate of the nickel stripping agent.

[0145] For ease of comparison, the nickel stripping agent formula is listed in Table 1, the corrosion evaluation is listed in Table 2, and the nickel stripping rate is listed in Table 3.

[0146] [Example 4]

[0147] 1. Nickel stripping agent formula

[0148] Sodium m-nitrobenzene sulfonate, 7.6 parts;

[0149] Sodium o-nitrobenzenesulfonate, 0.4 part;

[0150] Monoethanolamine, 1.6 parts;

[0151] EDTA-4Na, (calculated as EDTA), 8.0 parts;

[0152] Na2SO3, 0.4 parts;

[0153] Sodium lauryl sulfate, 0.8 part;

[0154] Defoaming agent, 0.8 parts.

[0155] 2. Preparation of nickel stripping agent working solution

[0156] (1) Take 70 parts of water, add 7.6 parts of sodium m-nitrobenzene sulfonate, 0.4 parts of sodium o-nitrobenzene sulfonate, 1.6 parts of monoethanolamine, and 8.0 parts of EDTA-4Na (calculated as EDTA), and stir to dissolve;

[0157] (2) Add 0.4 parts of Na2SO3 and stir to dissolve;

[0158] (3) adding 0.8 parts of sodium lauryl sulfate and 0.8 parts of defoamer and stirring to dissolve;

[0159] (4) Add water to 100 parts and stir evenly;

[0160] (5) Use a small amount of 10% by weight sulfuric acid aqueous solution to adjust the pH of the working solution to 9.0.

[0161] 3. Nickel stripping rate and corrosion evaluation

[0162] The above nickel stripping agent working solution was used as a test solution to evaluate the corrosion of the nickel stripping agent and the nickel stripping rate of the nickel stripping agent.

[0163] For ease of comparison, the nickel stripping agent formula is listed in Table 1, the corrosion evaluation is listed in Table 2, and the nickel stripping rate is listed in Table 3.

[0164] [Example 5]

[0165] 1. Nickel stripping agent formula

[0166] Sodium m-nitrobenzene sulfonate, 8.0 parts;

[0167] Diethanolamine, 1.6 parts;

[0168] EDTA-4Na, (calculated as EDTA), 8.0 parts;

[0169] Na2SO3, 0.4 parts;

[0170] Sodium lauryl sulfate, 0.8 part;

[0171] Defoaming agent, 0.8 parts.

[0172] 2. Preparation of nickel stripping agent working solution

[0173] (1) Take 70 parts of water, add 8.0 parts of sodium m-nitrobenzene sulfonate, 1.6 parts of diethanolamine, and 8.0 parts of EDTA-4Na (calculated as EDTA), and stir to dissolve;

[0174] (2) Add 0.4 parts of Na2SO3 and stir to dissolve;

[0175] (3) adding 0.8 parts of sodium lauryl sulfate and 0.8 parts of defoamer and stirring to dissolve;

[0176] (4) Add water to 100 parts and stir evenly;

[0177] (5) Use a small amount of 10% by weight sulfuric acid aqueous solution to adjust the pH of the working solution to 9.0.

[0178] 3. Nickel stripping rate and corrosion evaluation

[0179] The above nickel stripping agent working solution was used as a test solution to evaluate the corrosion of the nickel stripping agent and the nickel stripping rate of the nickel stripping agent.

[0180] For ease of comparison, the nickel stripping agent formula is listed in Table 1, the corrosion evaluation is listed in Table 2, and the nickel stripping rate is listed in Table 3.

[0181] [Example 6]

[0182] 1. Nickel stripping agent formula

[0183] Sodium m-nitrobenzene sulfonate, 8.0 parts;

[0184] Triethanolamine, 1.6 parts;

[0185] EDTA-4Na, (calculated as EDTA), 8.0 parts;

[0186] Na2SO3, 0.4 parts;

[0187] Sodium lauryl sulfate, 0.8 part;

[0188] Defoaming agent, 0.8 parts.

[0189] 2. Preparation of nickel stripping agent working solution

[0190] (1) Take 70 parts of water, add 8.0 parts of sodium m-nitrobenzene sulfonate, 1.6 parts of triethanolamine, and 8.0 parts of EDTA-4Na (calculated as EDTA), and stir to dissolve;

[0191] (2) Add 0.4 parts of Na2SO3 and stir to dissolve;

[0192] (3) adding 0.8 parts of sodium lauryl sulfate and 0.8 parts of defoamer and stirring to dissolve;

[0193] (4) Add water to 100 parts and stir evenly;

[0194] (5) Use a small amount of 10% by weight sulfuric acid aqueous solution to adjust the pH of the working solution to 9.0.

[0195] 3. Nickel stripping rate and corrosion evaluation

[0196] The above nickel stripping agent working solution was used as a test solution to evaluate the corrosion of the nickel stripping agent and the nickel stripping rate of the nickel stripping agent.

[0197] For ease of comparison, the nickel stripping agent formula is listed in Table 1, the corrosion evaluation is listed in Table 2, and the nickel stripping rate is listed in Table 3.

[0198] [Example 7]

[0199] 1. Nickel stripping agent formula

[0200] Sodium m-nitrobenzene sulfonate, 8.0 parts;

[0201] Monoethanolamine, 1.5 parts;

[0202] Triethanolamine, 0.1 part;

[0203] EDTA-4Na, (calculated as EDTA), 8.0 parts;

[0204] Na2SO3, 0.4 parts;

[0205] Sodium lauryl sulfate, 0.8 part;

[0206] Defoaming agent, 0.8 parts.

[0207] 2. Preparation of nickel stripping agent working solution

[0208] (1) Take 70 parts of water, add 8.0 parts of sodium m-nitrobenzene sulfonate, 1.5 parts of monoethanolamine, 0.1 parts of triethanolamine, and 8.0 parts of EDTA-4Na (calculated as EDTA), and stir to dissolve;

[0209] (2) Add 0.4 parts of Na2SO3 and stir to dissolve;

[0210] (3) adding 0.8 parts of sodium lauryl sulfate and 0.8 parts of defoamer and stirring to dissolve;

[0211] (4) Add water to 100 parts and stir evenly;

[0212] (5) Use a small amount of 10% by weight sulfuric acid aqueous solution to adjust the pH of the working solution to 9.0.

[0213] 3. Nickel stripping rate and corrosion evaluation

[0214] The above nickel stripping agent working solution was used as a test solution to evaluate the corrosion of the nickel stripping agent and the nickel stripping rate of the nickel stripping agent.

[0215] For ease of comparison, the nickel stripping agent formula is listed in Table 1, the corrosion evaluation is listed in Table 2, and the nickel stripping rate is listed in Table 3.

[0216] [Example 8]

[0217] 1. Nickel stripping agent formula

[0218] Sodium m-nitrobenzene sulfonate, 7.6 parts;

[0219] Sodium o-nitrobenzenesulfonate, 0.4 part;

[0220] Monoethanolamine, 1.5 parts;

[0221] Triethanolamine, 0.1 part;

[0222] EDTA-4Na, (calculated as EDTA), 8.0 parts;

[0223] Na2SO3, 0.4 parts;

[0224] Sodium lauryl sulfate, 0.8 part;

[0225] Defoaming agent, 0.8 parts.

[0226] 2. Preparation of nickel stripping agent working solution

[0227] (1) Take 70 parts of water, add 7.6 parts of sodium m-nitrobenzene sulfonate, 0.4 parts of sodium o-nitrobenzene sulfonate, 1.5 parts of monoethanolamine, 0.1 parts of triethanolamine, and 8.0 parts of EDTA-4Na (calculated as EDTA), and stir to dissolve;

[0228] (2) Add 0.4 parts of Na2SO3 and stir to dissolve;

[0229] (3) adding 0.8 parts of sodium lauryl sulfate and 0.8 parts of defoamer and stirring to dissolve;

[0230] (4) Add water to 100 parts and stir evenly;

[0231] (5) Use a small amount of 10% by weight sulfuric acid aqueous solution to adjust the pH of the working solution to 9.0.

[0232] 3. Nickel stripping rate and corrosion evaluation

[0233] The above nickel stripping agent working solution was used as a test solution to evaluate the corrosion of the nickel stripping agent and the nickel stripping rate of the nickel stripping agent.

[0234] For ease of comparison, the nickel stripping agent formula is listed in Table 1, the corrosion evaluation is listed in Table 2, and the nickel stripping rate is listed in Table 3.

[0235] It can be seen from the data in Table 1 and Table 2 that the corrosion amount of Example 7 using both monoethanolamine and triethanolamine is significantly smaller than that of Example 1 using only monoethanolamine and Example 6 using only triethanolamine, and the corrosion resistance is significantly improved. Monoethanolamine and triethanolamine have an obvious synergistic effect in improving the corrosion resistance.

[0236] It can be seen from Table 1 and Table 3 that, compared with Examples 1 and 2, the nickel stripping rate of Example 4 is significantly improved. The reason is that sodium m-nitrobenzene sulfonate and sodium o-nitrobenzene sulfonate cooperate with each other, reduce side reactions, and improve the nickel stripping rate; and compared with Example 1 and Example 6, the nickel stripping rate of Example 7 is also improved. When monoethanolamine and triethanolamine exist at the same time, it is beneficial to the complexation of nickel and has a mutually promoting effect; in addition, the nickel stripping rate of Example 8 is greatly improved compared with other examples. This is because the system simultaneously contains sodium m-nitrobenzene sulfonate and sodium mono- and triethanolamine, which cooperate to jointly promote the removal of nickel.

[0237] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

[0238] Table 1

[0239] (parts by weight)

[0240]

[0241] Table 2

[0242]

[0243] Table 3

[0244] (μm / h)

[0245]

Claims

1. An environmentally friendly nickel stripping agent, comprising, by weight: Nickel oxidant, 8 parts; Base metal corrosion inhibitor, 0.4~24 parts; Nickel complexing agent, 4 to 16 parts; The nickel oxidant comprises a nitrobenzene sulfonic acid compound; The nitrobenzene sulfonic acid compound comprises a first nitrobenzene sulfonic acid compound and a second nitrobenzene sulfonic acid compound, the first nitrobenzene sulfonic acid compound is an m-nitrobenzene sulfonic acid compound, and the second nitrobenzene sulfonic acid compound is an o-nitrobenzene sulfonic acid compound; the molar ratio of the second nitrobenzene compound to the first nitrobenzene sulfonic acid compound is greater than 0 and less than 0.

1.

2. The nickel stripping agent according to claim 1, characterized in that The substrate metal corrosion inhibitor is at least one alcohol amine selected from the group consisting of monoethanolamine, diethanolamine and triethanolamine.

3. The nickel stripping agent according to claim 1, characterized in that The nickel complexing agent is selected from citric acid, citric acid salts, gluconic acid, gluconic acid salts, and aminocarboxylic acid complexing agents; the aminocarboxylic acid complexing agent is selected from at least one of the material group consisting of glycine, glutamic acid, ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid and their salts.

4. The nickel stripping agent according to claim 1, characterized in that Nickel stripping agent is alkaline.

5. The nickel stripping agent according to claim 4, characterized in that The nickel stripping agent includes 0.05 to 5 parts of a stabilizer.

6. The nickel stripping agent according to claim 5, characterized in that The stabilizer includes a salt of sulfurous acid or a salt of thiosulfuric acid.

7. The nickel stripping agent according to claim 1, characterized in that The nickel stripping agent includes 0.05 to 5 parts of a surfactant.

8. The nickel stripping agent according to claim 7, characterized in that The surfactant is an anionic surfactant.

9. The nickel stripping agent according to claim 8, characterized in that The anionic surfactant is at least one selected from the group consisting of salts of alkylbenzene sulfonic acid, salts of alkyl sulfate, salts of fatty alcohol polyoxyethylene sulfate and salts of α-olefin sulfonic acid.

10. The nickel stripping agent according to claim 1, characterized in that The nickel stripping agent includes 0.05 to 5 parts of a defoaming agent.

11. The nickel stripping agent according to claim 10, characterized in that The defoamer is at least one selected from the group consisting of fatty acid ester defoamers, amide defoamers, phosphate defoamers, silicone defoamers, polyether defoamers and polyether-modified polysiloxane defoamers.

12. Use of the nickel stripping agent according to any one of claims 1 to 11 in nickel stripping.

13. A method for stripping nickel, comprising the following steps: (1) obtaining a nickel stripping agent working solution containing the nickel stripping agent according to any one of claims 1 to 11; (2) contacting the nickel-plated workpiece to be stripped of nickel with the nickel stripping agent working solution to convert the nickel plating layer into a black substance to obtain a semi-finished nickel stripped workpiece; (3) The semi-finished nickel-stripped workpiece is brought into contact with a cleaning solution, and the black matter is removed from the surface of the semi-finished nickel-stripped workpiece by means of physical force.

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