Environment-friendly deplating agent for neodymium iron boron material as well as preparation method and use method of environment-friendly deplating agent

Abstract

The invention relates to the technical field of environment-friendly materials, and provides an environment-friendly deplating agent for neodymium-iron-boron materials and a preparation method and a using method thereof.The deplating agent comprises, by weight, 1%-5% of ammonium carbonate, 5%-10% of sodium dihydrogen phosphate or trisodium phosphate, 1%-5% of sodium hydroxide, 10%-15% of potassium citrate and the balance deionized water. The cleaning agent comprises the following components in percentage by weight: 40-50% of a cleaning agent, 5-10% of amino triethanol, 15-20% of hexamethylenetetramine or ethylenediamine, 40-50% of deionized water, and 0.1-1% of a chelating agent and a surface repairing agent; wherein the surface repairing agent is a composition comprising 0.1-1% by weight of nanoparticles and 0.1-0.5% by weight of a rare earth element compound; the nanoparticles and the rare earth element compound are used for forming a complex for repairing small surface defects; the rare earth element compound comprises one or more of a dysprosium compound, a praseodymium compound and / or a samarium compound; the nano particles comprise nano neodymium oxide and nano iron oxide, and the mass ratio of the nano neodymium oxide to the nano iron oxide is (1: 1)-(2: 3).

Description

Technical Field

[0001] The invention relates to the technical field of fireproof materials, in particular to an environmentally friendly deplating agent for NdFeB materials and a preparation method and a use method thereof. Background Art

[0002] With the widespread application of NdFeB rare earth permanent magnet materials in electronic products, automotive fields, medical equipment and other industries, the demand for its surface treatment technology is also increasing. In order to improve the corrosion resistance and aesthetics of NdFeB materials, it is usually necessary to electroplate them, such as nickel plating, copper plating, zinc plating, zinc-nickel alloy plating and chemical nickel plating. However, due to the limitations of the production process and operational errors, defective products are often produced and need to be reworked and deplated. Traditional deplating methods mostly use sodium cyanide as the main material. Although sodium cyanide has a strong deplating ability, its highly toxic nature poses a great threat to operators and the environment. In addition, the deplating solution configured with sodium cyanide will cause certain damage to the NdFeB substrate and performance, resulting in a decrease in the qualified rate of deplated products.

[0003] In recent years, with the improvement of environmental awareness and the emphasis on safe production, the development of a cyanide-free, environmentally friendly and efficient stripping agent has become an urgent need in the industry. Although the existing cyanide-free stripping agents have solved the toxicity problem of sodium cyanide to a certain extent, they still have shortcomings in stripping efficiency, scope of application and substrate protection. For example, some cyanide-free stripping agents can only strip specific coatings and cannot process multiple coatings at the same time, which increases production costs and operational complexity. In addition, when some cyanide-free stripping agents are used under medium temperature conditions, the stripping speed is slow and the protection effect on the substrate is not ideal. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an environmentally friendly stripping agent for NdFeB materials and a preparation method and a use method thereof, which solve the problems of the above-mentioned background technology.

[0005] According to a first aspect of the present invention, an environmentally friendly deplating agent for NdFeB material is provided. Based on the total weight of the deplating agent, the deplating agent contains, in terms of weight percentage:

[0006] 1-5 wt% of ammonium carbonate, 5-10 wt% of sodium dihydrogen phosphate or trisodium phosphate, 1-5 wt% of sodium hydroxide, 10-15 wt% of potassium citrate, 5-10 wt% of aminotriethanol, 15-20 wt% of hexamethylenetetramine or ethylenediamine, 40-50 wt% of deionized water, and 0.1-1 wt% of a chelating agent and a surface repair agent;

[0007] Wherein, the surface repair agent is a composition comprising 0.1-1 wt% of nanoparticles and 0.1-0.5 wt% of rare earth element compounds; the nanoparticles and rare earth element compounds are used to form a complex for repairing tiny surface defects;

[0008] The rare earth element compound includes one or more of a dysprosium compound, a praseodymium compound and / or a samarium compound;

[0009] The nanoparticles include nano-neodymium oxide and nano-iron oxide, and the mass ratio of the nano-neodymium oxide to the nano-iron oxide is 1:1-2:3.

[0010] Optionally, the chelating agent is used to form a stable chelate with the metal ion.

[0011] Optionally, the surface repair agent is used to chemically react with the surface of the NdFeB material during the stripping process to repair tiny defects or damages on the surface.

[0012] Optionally, the surface repair agent can chemically react with the surface of the NdFeB material during the stripping process to repair tiny defects or damage on the surface and improve the surface quality and performance.

[0013] Optionally, the chelating agent is selected from one or more of ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), and hydroxyethylidene diphosphonic acid (HEDP).

[0014] Optionally, the particle size of the nanoparticles is between 1-100 nanometers.

[0015] Alternatively, nanoparticles can be evenly dispersed in the stripping agent and attached to the surface of NdFeB to fill tiny defects and improve the surface quality.

[0016] Optionally, the ratio of the mass of the dysprosium compound to the mass of the praseodymium compound and / or the samarium compound is 1:2-1:4;

[0017] The dysprosium compound includes one or both of dysprosium nitrate and dysprosium chloride;

[0018] The praseodymium compound includes one or both of praseodymium nitrate and praseodymium chloride;

[0019] The samarium compound includes one or more of samarium nitrate and samarium chloride.

[0020] Optionally, praseodymium nitrate (Pr(NO3)3) and praseodymium chloride (PrCl3) can provide a repairing effect and have good solubility. Praseodymium compounds can form stable complexes with the neodymium element in neodymium iron boron, which helps to repair surface defects.

[0021] Optionally, dysprosium nitrate (Dy(NO3)3) and dysprosium chloride (DyCl3) can also provide a repair effect and help improve the corrosion resistance of the material. Dysprosium compounds can also work synergistically with the neodymium element in NdFeB, especially in improving magnetic properties.

[0022] Optionally, samarium nitrate (Sm(NO3)3) and samarium chloride (SmCl3) can form stable complexes with the neodymium element in NdFeB, which helps to repair surface defects, can also provide a repair effect, and help improve the corrosion resistance of the material.

[0023] Compounds of praseodymium nitrate, praseodymium chloride, dysprosium nitrate, dysprosium chloride, samarium nitrate and samarium chloride can react chemically with the neodymium element in the NdFeB material during the stripping process to form stable complexes. These complexes help repair tiny surface defects and provide an additional protective layer. The enrichment of neodymium in the NdFeB material is limited, and nano-neodymium oxide can increase the complexation between the compound and the neodymium element, thereby forming a film on the surface of the NdFeB material and filling the tiny defects on the surface of the NdFeB material. Nano-iron oxide can be evenly dispersed in the stripping agent, attached to the surface of the NdFeB, and fill the tiny defects. The compounding effect of compounds of praseodymium nitrate, praseodymium chloride, dysprosium nitrate, dysprosium chloride, samarium nitrate and samarium chloride and nanoparticles enhances the density and smoothness of the surface, reduces the occurrence of oxidation and corrosion, and improves the surface quality.

[0024] Since the particle size of nano-neodymium oxide is very small (between 1 and 100 nanometers), nano-neodymium oxide has an extremely high specific surface area. This means that the unit mass of nano-neodymium oxide can provide a larger surface contact area, has better dispersibility, can form a more dense complex with the compound, and can fill tiny gaps more stably. In addition, the content of nano-neodymium oxide added in the present invention is slightly less than that of the compound, thereby reducing the risk of agglomeration between neodymium oxide and the compound when not in use.

[0025] More importantly, as a permanent magnet material, NdFeB rare earth will affect its magnetic effect when there is slight damage on its surface, while praseodymium and samarium can improve the remanence and maximum magnetic energy product of NdFeB materials, thereby enhancing its magnetic properties and reducing the damage to magnetic properties caused by stripping agents. Dysprosium can significantly improve the coercivity and thermal stability of NdFeB materials, especially under high temperature conditions. These compounds have high oxidation resistance and corrosion resistance, which can reduce the oxidation and corrosion of NdFeB materials during the stripping process.

[0026] Optionally, the surface repair agent further comprises one of neodymium nitrate, neodymium chloride, ferric sulfate, ferric chloride, boric acid and borax.

[0027] Alternatively, the neodymium salt can chemically react with defects on the surface of NdFeB to fill the tiny pores.

[0028] Optionally, the iron salt can react with the iron element on the surface of NdFeB to enhance the density of the surface.

[0029] Optionally, the boron compound can react with the boron element on the surface of NdFeB to repair minor damage on the surface.

[0030] Optionally, the pH value of the stripping agent is 10-15, and the pH value of the stripping agent is controlled by adjusting the amount of sodium hydroxide to optimize the stripping effect and protect the NdFeB substrate.

[0031] Optionally, the stripping agent further contains 0.5-2 wt % of an antioxidant, which can effectively prevent oxidation of the metal surface during the stripping process, thereby improving the stripping efficiency and the surface quality of the NdFeB substrate.

[0032] Optionally, the antioxidant is selected from one or more of ascorbic acid, sodium sulfite and sodium metabisulfite.

[0033] In a second aspect, an embodiment of the present invention provides a method for preparing an environmentally friendly stripping agent for NdFeB materials, comprising the following steps:

[0034] S1: 40-50 wt % of deionized water, 15-20 wt % of hexamethylenetetramine or ethylenediamine, and 0.1-0.5 wt % of corrosion inhibitor W are mixed to form a solution a;

[0035] S2: mixing the remaining deionized water with 1-5 wt % of ammonium carbonate, 5-10 wt % of sodium dihydrogen phosphate or trisodium phosphate, 1-5 wt % of sodium hydroxide, 10-15 wt % of potassium citrate, and 0.1-1 wt % of a chelating agent to form a solution b;

[0036] S3: Mixing solution a in S1 with solution b in S2 to form solution c;

[0037] S4: mixing the solution c in step S3 with 5-10 wt % of aminotriethanol, 0.5-2 wt % of an antioxidant and a surface repair agent to prepare the stripping agent.

[0038] In a third aspect, an embodiment of the present invention provides a method for using an environmentally friendly stripping agent on a NdFeB material, comprising the following steps:

[0039] (1) Soaking the NdFeB product that needs to be reworked and deplated in the deplating agent, and adjusting the deplating time according to the thickness of the coating, ranging from 5 to 180 minutes;

[0040] (2) After the stripping is completed, use ultrasonic cleaning to complete the stripping process;

[0041] (3) During the stripping process, the stripping agent is used at 70-100°C without damaging the NdFeB substrate and its performance.

[0042] Optionally, different immersion times can be used for different coatings, for example, for nickel coating, the immersion time is 10 minutes; for copper coating, the immersion time is 15 minutes; for zinc coating, the immersion time is 20 minutes; for zinc-nickel alloy coating, the immersion time is 25 minutes; for chemical nickel coating, the immersion time is 30 minutes.

[0043] Optionally, when the stripping agent is used under medium temperature conditions, the chelating agent forms a stable chelate with metal ions such as nickel, copper, and zinc, which significantly improves the stripping efficiency and reduces harmful byproducts generated during the stripping process.

[0044] Optionally, the antioxidant effectively prevents oxidation of the metal surface during the stripping process, thereby improving the stripping efficiency and the surface quality of the NdFeB substrate.

[0045] Optionally, during the stripping process, the components of the stripping agent work synergistically to significantly improve the stripping efficiency, shorten the stripping time, and do not damage the NdFeB substrate and performance.

[0046] The environmentally friendly stripping agent for NdFeB materials provided by the present invention not only significantly improves the stripping efficiency and surface quality, but also enhances the magnetic properties of NdFeB materials by introducing nanoparticles and rare earth element compounds in a specific proportion. In addition, the flexibility and environmental friendliness of the formula make it suitable for a variety of application scenarios, with broad application prospects and significant competitive advantages. Through unique formula design and component selection, it is possible to quickly and efficiently remove a variety of coatings such as nickel, copper, zinc, zinc-nickel alloy and chemical nickel plating on the surface of NdFeB materials.

[0047] The present invention effectively resists oxidation of the metal surface and improves the stripping efficiency by adding ammonium carbonate and aminotriethanol as surfactants; sodium dihydrogen phosphate or trisodium phosphate and sodium hydroxide are used as corrosion inhibitors to stabilize the pH value of the stripping agent and prevent corrosion of the NdFeB substrate; potassium citrate and hexamethylenetetramine or ethylenediamine are used as complexing agents to form stable chelates with metal ions such as nickel, copper, and zinc to enhance the complexing effect of the stripping agent. These components not only significantly improve the stripping efficiency and shorten the stripping time through synergistic effects, but also do not damage the NdFeB substrate and performance, thereby ensuring the high quality of the stripping product. In addition, the stripping agent reduces the generation of harmful byproducts and has good environmental performance and economic benefits.

[0048] The pH value of the stripping agent of the present invention is controlled between 10 and 15, which not only ensures efficient stripping effect, but also avoids the corrosion risk that may be caused by too high pH value. Adding an antioxidant (such as ascorbic acid) helps to prevent oxidation of the metal surface during the stripping process, improves the stripping efficiency and the surface quality of the NdFeB substrate, and meets environmental protection requirements.

[0049] Although some rare earth element compounds and nanoparticles are more expensive, their significant performance improvements can offset the cost issue, especially in high-end applications such as high-performance magnet manufacturing and repair. Since the surface quality and magnetic properties of the material after stripping are effectively protected and improved, the scrap rate caused by surface defects is reduced, which indirectly reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The present invention is a flow chart of a method for preparing an environmentally friendly stripping agent for NdFeB materials according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The embodiments of the present application provide an environmentally friendly stripping agent for NdFeB materials and a preparation method and a use method thereof. DETAILED DESCRIPTION

[0053] Example 1: Basic formulation

[0054] Ammonium carbonate: 3%

[0055] Sodium dihydrogen phosphate: 7%

[0056] Sodium hydroxide: 3%

[0057] Potassium citrate: 12%

[0058] Aminotriethanol: 7%

[0059] Hexamethylenetetramine: 18%

[0060] Deionized water: 45%

[0061] Chelating agent (EDTA): 0.5%

[0062] Surface repair agent (nano-neodymium oxide: nano-iron oxide = 1:1, dysprosium nitrate: praseodymium chloride = 1:2): 0.6% (0.3% nanoparticles + 0.3% rare earth element compounds)

[0063] Antioxidant (ascorbic acid): 1%

[0064] Example 2: Increasing the content of nanoparticles

[0065] Changes: Nanoparticle content increased from 0.3% to 0.6%, rare earth element compounds remained unchanged.

[0066] Other ingredients remain unchanged

[0067] Example 3: Increasing the content of rare earth element compounds

[0068] Changes: Rare earth element compound content increased from 0.3% to 0.5%, nanoparticles remained unchanged.

[0069] Other ingredients remain unchanged

[0070] Example 4: Adjusting the ratio of dysprosium to praseodymium

[0071] Change: The ratio of dysprosium compound (dysprosium nitrate) to praseodymium compound (praseodymium chloride) was adjusted from 1:2 to 1:4.

[0072] Other ingredients remain unchanged

[0073] Comparative Example 1: No Nanoparticles

[0074] Variation: Nanoparticles removed, only rare earth element compounds (0.3%) retained.

[0075] Other ingredients remain unchanged

[0076] Comparative Example 2: No rare earth element compound

[0077] Variation: rare earth element compounds were removed, leaving only nanoparticles (0.3%).

[0078] Other ingredients remain unchanged

[0079] Experimental example:

[0080] According to the formulations in the embodiments and comparative examples, different stripping agents were prepared respectively.

[0081] During mixing, ensure that all ingredients are evenly dispersed and adjust the pH to 10-15 by gradually adding sodium hydroxide.

[0082] (1) Stripping experiment:

[0083] Prepare NdFeB samples of the same size and coating thickness.

[0084] Immerse the sample in the deplating agent, control the temperature within the range of 70-100°C, and record the deplating time.

[0085] Use ultrasonic cleaning to clean, observe and record the state of the sample surface.

[0086] The surface state after stripping was analyzed using electron microscopy and energy dispersive spectroscopy (EDS).

[0087] The experimental data are shown in Table 1:

[0088] Table 1. Deplating experimental data of the deplating agent in Examples 1-4 and Comparative Examples 1-2

[0089]

[0090]

[0091] From this we can see that:

[0092] Chelating agent: Increasing the content of EDTA can significantly improve the stripping efficiency and reduce the stripping time.

[0093] Effect of nanoparticles: Increasing the content of nanoparticles can significantly improve the stripping efficiency (from 60 minutes to 55 minutes) and provide better surface repair effect, making the surface smoother and filling small defects.

[0094] Role of rare earth element compounds: Increasing the content of rare earth element compounds can further improve surface quality and magnetic properties while reducing surface defects.

[0095] Adjustment of the ratio of dysprosium to praseodymium: Adjusting the ratio of dysprosium to praseodymium to 1:4 can make the surface very smooth and the minor defects are almost completely repaired.

[0096] Comparative experimental results: A control sample without nanoparticles or rare earth element compounds showed that these two ingredients are essential for improving stripping efficiency, surface quality and magnetic properties.

[0097] (2) Magnetic performance test

[0098] Sample preparation: Use NdFeB samples of the same size and coating thickness.

[0099] Stripping treatment: Stripping treatment was carried out according to the formulations in the embodiments and comparative examples, the temperature was controlled within the range of 70-100° C., and the stripping time was recorded.

[0100] Cleaning: Use ultrasonic cleaning to ensure that there is no residual deplating agent on the surface.

[0101] Magnetic properties test: The remanence (Br), coercive force (Hc) and maximum magnetic energy product (BHmax) of the sample after stripping were measured using a vibrating sample magnetometer (VSM). The results are shown in Table 2:

[0102] Table 2. Magnetic performance experimental data of the stripping agent in Examples 1-4 and Comparative Examples 1-2

[0103]

[0104]

[0105] By comparing Example 2 with Example 1, it can be seen that increasing the content of nanoparticles (from 0.3% to 0.6%) increases the remanence, coercive force and maximum magnetic energy product, indicating that nanoparticles help improve magnetic properties.

[0106] By comparing Example 3 with Example 1, it can be seen that increasing the rare earth element compound content (from 0.3% to 0.5%) further improves the remanence, coercive force and maximum magnetic energy product, indicating that the rare earth element compound has a significant improvement effect on the magnetic properties.

[0107] By comparing Example 4 with Example 1, it can be seen that by adjusting the ratio of dysprosium to praseodymium to 1:4, the remanence, coercive force and maximum magnetic energy product are significantly improved, especially the coercive force is increased by about 15%, indicating that appropriately adjusting the ratio of rare earth elements can significantly optimize the magnetic properties.

[0108] By comparing Comparative Example 1 and Example 1, it can be seen that without the nanoparticles, the remanence, coercive force and maximum magnetic energy product are all reduced, indicating that nanoparticles are crucial to maintaining and improving magnetic properties.

[0109] By comparing Comparative Example 2 with Example 1, it can be seen that without rare earth element compounds, the remanence, coercive force and maximum magnetic energy product are significantly reduced, especially the coercive force is reduced by about 10%, indicating that rare earth element compounds are also important for improving magnetic properties.

[0110] It can be seen that the effect of nanoparticles is that increasing the content of nanoparticles (from 0.3% to 0.6%) reduces the stripping time from 60 minutes to 55 minutes. This shows that nanoparticles can significantly increase the reaction rate of the stripping agent, thereby shortening the stripping time and improving production efficiency.

[0111] Nanoparticles and rare earth element compounds work together: In all examples containing nanoparticles and rare earth element compounds, the surface of the NdFeB material after stripping is smoother, and tiny defects are repaired or filled. The comparative samples without nanoparticles or rare earth element compounds show obvious corrosion marks and more surface defects, further verifying the important contribution of these two components to surface quality.

[0112] Improvement of remanence, coercivity and maximum magnetic energy product: The remanence (Br), coercivity (Hc) and maximum magnetic energy product (BHmax) of all embodiments are improved to varying degrees. In particular, when the ratio of dysprosium to praseodymium is adjusted to 1:4, the coercivity is increased by about 15% and the maximum magnetic energy product reaches 450 kJ / m 3 The magnetic properties of the comparative samples without nanoparticles or rare earth element compounds decreased significantly, especially the coercivity decreased by 10%-15%, indicating that these components are essential for maintaining and improving the magnetic properties.

[0113] By adjusting the content of nanoparticles, rare earth element compounds, and the ratio of dysprosium to praseodymium, the stripper formulation can be flexibly optimized in different application scenarios to meet specific performance requirements. The stripper is suitable for applications that require efficient stripping, high-quality surface, and good magnetic property retention, such as reworking of high-performance NdFeB magnets.

[0114] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0115] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. An environmentally friendly stripping agent for NdFeB materials, characterized in that: Based on the total weight of the stripping agent, the stripping agent contains, by weight percentage: 1-5 wt% of ammonium carbonate, 5-10 wt% of sodium dihydrogen phosphate or trisodium phosphate, 1-5 wt% of sodium hydroxide, 10-15 wt% of potassium citrate, 5-10 wt% of aminotriethanol, 15-20 wt% of hexamethylenetetramine or ethylenediamine, 40-50 wt% of deionized water, and 0.1-1 wt% of a chelating agent and a surface repair agent; Wherein, the surface repair agent is a composition comprising 0.1-1 wt% of nanoparticles and 0.1-0.5 wt% of rare earth element compounds; the nanoparticles and rare earth element compounds are used to form a complex for repairing tiny surface defects; The rare earth element compound includes one or more of a dysprosium compound, a praseodymium compound and / or a samarium compound; The nanoparticles include nano-neodymium oxide and nano-iron oxide, and the mass ratio of the nano-neodymium oxide to the nano-iron oxide is 1:1-2:

3.

2. The environmentally friendly stripping agent for NdFeB materials according to claim 1, characterized in that: The chelating agent is selected from one or more of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and hydroxyethylidene diphosphonic acid.

3. The environmentally friendly stripping agent for NdFeB materials according to claim 1, characterized in that: The surface repair agent also includes one of neodymium nitrate, neodymium chloride, ferric sulfate, ferric chloride, boric acid and borax.

4. The environmentally friendly stripping agent for NdFeB materials according to claim 1, characterized in that: The particle size of the nanoparticles is between 1 and 100 nanometers.

5. The environmentally friendly stripping agent for NdFeB materials according to claim 1, characterized in that: The ratio of the mass of the dysprosium compound to the mass of the praseodymium compound and / or the samarium compound is 1:2-1:4; The dysprosium compound includes one or both of dysprosium nitrate and dysprosium chloride; The praseodymium compound includes one or both of praseodymium nitrate and praseodymium chloride; The samarium compound includes one or more of samarium nitrate and samarium chloride.

6. The environmentally friendly stripping agent for NdFeB materials according to claim 1, characterized in that: The pH value of the stripping agent is 10-15.

7. The environmentally friendly stripping agent for NdFeB materials according to claim 1, characterized in that: The stripping agent also contains 0.5-2 weight % of an antioxidant.

8. The environmentally friendly stripping agent for NdFeB materials according to claim 7, characterized in that: The antioxidant is selected from one or more of ascorbic acid, sodium sulfite and sodium pyrosulfite.

9. A method for preparing an environmentally friendly stripping agent for NdFeB materials as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: Mixing 40-50 wt % of deionized water and 15-20 wt % of hexamethylenetetramine or ethylenediamine to form a solution a; The remaining deionized water is mixed with 1-5 wt % of ammonium carbonate, 5-10 wt % of sodium dihydrogen phosphate or trisodium phosphate, 1-5 wt % of sodium hydroxide, 10-15 wt % of potassium citrate, and 0.1-1 wt % of a chelating agent to form a solution b; Mixing the solution a with the solution b to form a solution c; The solution c is mixed with 5-10 wt % of aminotriethanol, 0.5-2 wt % of an antioxidant and a surface repair agent to prepare the deplating agent.

10. A method for using the stripping agent according to any one of claims 1 to 8, characterized in that: The following steps are involved: Soak the NdFeB product that needs to be reworked and deplated in the deplating agent, and adjust the deplating time according to the thickness of the coating, ranging from 5 to 180 minutes; After the stripping is completed, use ultrasonic cleaning to complete the stripping process; During the stripping process, the stripping agent is used at 70-100° C. without damaging the NdFeB substrate and its performance.

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