Aluminum-nickel-cobalt magnet and preparation method thereof
By adding corrosion-resistant components and phosphating treatment to AlNiCo magnets, silicon nitride ceramics and phosphating films are generated, solving the problem of decreased corrosion resistance of AlNiCo magnets caused by the addition of heavy rare earth elements, and improving performance stability and corrosion resistance under high temperature environments.
Patent Information
- Application Number
- CN202511702629.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-19
- Publication Date
- 2026-02-24
AI Technical Summary
The addition of heavy rare earth elements to AlNiCo magnets reduces their corrosion resistance at high temperatures, affecting their application under high-temperature conditions.
By adding corrosion-resistant components such as methylvinylsilazane or polysilazane resin to AlNiCo magnets and treating them with a phosphating solution composed of potassium dihydrogen phosphate at high temperature, silicon nitride ceramics and a phosphating film are generated, forming a dense physical barrier to improve corrosion resistance.
While maintaining high intrinsic coercivity, it significantly improves the corrosion resistance of AlNiCo magnets, extends service life, and reduces wear.
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Abstract
Description
Technical Field
[0001] This application relates to the field of AlNiCo magnet preparation, specifically to an AlNiCo magnet and its preparation method. Background Technology
[0002] AlNiCo magnets are alloys composed of elements such as neodymium (Ni), iron (Fe), and boron (Co). Developed and successfully produced in the 1980s, AlNiCo magnets are a third-generation rare-earth permanent magnet material. Due to their high remanence, high coercivity, high energy product, and excellent dynamic recovery characteristics, they are currently the most cost-effective magnetic material. Because of their superior magnetic properties, they are known as the "King of Magnets" and play an important role in fields such as medicine, automobiles, home appliances, aerospace, and communications, showing broad application prospects.
[0003] Intrinsic coercivity is a core indicator used to measure the demagnetization resistance of magnetic materials. In the application of AlNiCo magnets, high-temperature environments are frequently encountered. Only magnetic materials with high intrinsic coercivity can effectively resist thermally activated demagnetization, ensuring that equipment maintains a stable magnetic field strength at high temperatures. Adding heavy rare earth elements is a common method to improve the intrinsic coercivity of AlNiCo magnets. However, the addition of heavy rare earth elements reduces the corrosion resistance of AlNiCo magnets, limiting the application of AlNiCo magnets with high intrinsic coercivity. Summary of the Invention
[0004] To address the issue that the corrosion resistance of AlNiCo magnets containing heavy rare earth elements decreases, this application provides a method for preparing AlNiCo magnets. By combining corrosion-resistant components and potassium dihydrogen phosphate in the phosphating solution at high temperatures, the method ensures high intrinsic coercivity of AlNiCo magnets while maintaining high corrosion resistance.
[0005] In a first aspect, this application provides a method for preparing an AlNiCo magnet, employing the following technical solution: A method for preparing an AlNiCo magnet includes the following steps: Melt casting: Metal raw materials are mixed according to the formula and the mixture is melted to obtain a molten liquid. The molten liquid is then cast into a strip to obtain a cast strip. Hydrogen-crushed grinding: The belt sheet is hydrogen-crushed into coarse powder, and the coarse powder is then passed through an air jet mill to obtain alloy powder. Press molding: The obtained alloy powder and corrosion-resistant components are placed in a mold and pressed to obtain a sintered green body; Sintering process: The green blank is sintered under nitrogen protection. After sintering, it is rapidly cooled to room temperature in stages and tempered to obtain AlNiCo magnets. Phosphating treatment: After surface treatment of the AlNiCo magnet, it is immersed in phosphating solution for high-temperature phosphating treatment, and then taken out and rinsed to obtain phosphated AlNiCo magnet; The metal raw material comprises the following components in parts by weight: Al 6.5-7 parts, Ni 19.5-21 parts, Co 0.90-1.03 parts, Tb 4-6 parts, Dy 0-1 parts, Co 1-2 parts, Fe 64-68 parts; The corrosion-resistant component includes at least one of methyl vinyl silazane and polysilazane resin; The phosphating solution comprises the following components at the following concentrations: potassium dihydrogen phosphate 30-100 g / L, phosphoric acid 100-200 g / L, and manganese nitrate 5-10 g / L; the temperature range of the high-temperature phosphating treatment is 85-98℃.
[0006] This application improves the corrosion resistance and intrinsic coercivity of AlNiCo magnets with added Tb and Dy by sintering corrosion-resistant components to generate silicon nitride ceramics. At the same time, the sintered AlNiCo magnets are subjected to phosphating treatment. The potassium ions in the phosphating solution react with the silicon nitride ceramics at high temperature to form a highly adhesive phosphating film, which further improves the corrosion resistance of the AlNiCo magnets, thereby preparing AlNiCo magnets.
[0007] By employing the aforementioned technical solution, the addition of heavy rare earth metals such as Tb and Dy to AlNiCo magnets is primarily aimed at enhancing the intrinsic coercivity of the magnets, thereby improving their performance stability under high-temperature environments. However, the addition of these heavy rare earth metals does indeed reduce the corrosion resistance of AlNiCo magnets.
[0008] Methylvinylsilazane and polysilazane resins can form a temporary adhesive network at low temperatures. This network structure provides additional support during the magnet greening stage, enhancing the mechanical strength of the green body. By reducing crack formation, these resins help improve the density and molding accuracy of the compact, thereby ensuring the structural integrity and performance consistency of the final magnet. During sintering, methylvinylsilazane and polysilazane resins decompose at high temperatures, producing silicon nitride ceramics. Silicon nitride ceramics can coat the grain boundaries and surfaces of AlNiCo magnets, forming a dense physical barrier. This barrier effectively inhibits the penetration of oxygen and corrosive media, thereby improving the corrosion resistance of the magnet.
[0009] Phosphating treatment forms a dense phosphating film on the magnet surface. This film effectively covers micropores and defects on the magnet surface, reducing direct contact between corrosive media and the magnet substrate, thus preventing these defects from becoming the starting point of corrosion. The formation of the phosphating film also makes the magnet surface smoother, reducing surface roughness. This helps reduce friction and wear between the magnet and its surrounding environment during use, extending the magnet's service life.
[0010] Potassium dihydrogen phosphate is a key component in the phosphating solution. After sintering, the corrosion-resistant component produces silicon nitride ceramics. Potassium ions form coordination bonds with nitrogen atoms on the silicon nitride ceramics at 85-98℃, thus generating a stable complex. The resulting phosphating film has stronger adhesion, further protecting the magnet substrate from corrosive media and improving the corrosion resistance of AlNiCo magnets.
[0011] This application improves the corrosion resistance of AlNiCo magnets with added Tb and Dy by sintering corrosion-resistant components to generate silicon nitride ceramics. At the same time, the sintered AlNiCo magnets are subjected to phosphating treatment. The potassium ions in the phosphating solution react with the silicon nitride ceramics at high temperature to form a highly adhesive phosphating film, which further improves the corrosion resistance of the AlNiCo magnets, thereby preparing AlNiCo magnets.
[0012] Preferably, the corrosion-resistant component is a polysilazane resin.
[0013] By employing the above-mentioned technical solutions, methyl vinyl silazane and polysilazane resins may release gases such as ammonia and carbon dioxide during high-temperature sintering, which could actually increase the porosity of the AlNiCo magnets. When the porosity is too high, defects such as micropores and surface roughness easily appear inside and on the surface of the magnet. These defects can easily become the starting point for corrosion in high-temperature and high-humidity environments, accelerating the corrosion process. In comparison, AlNiCo magnets with added polysilazane resin exhibit better corrosion resistance than those with added methyl vinyl silazane, possibly because polysilazane resin releases less gas.
[0014] Preferably, the corrosion-resistant component is 0.2-0.5 parts by weight.
[0015] Preferably, the corrosion-resistant component is 0.4 parts by weight.
[0016] By adopting the above technical solution, when the content of corrosion-resistant components is too low, the effect on improving the corrosion resistance of AlNiCo magnets is not obvious; when the content of corrosion-resistant components is too high, the corrosion-resistant components will generate more gas during high-temperature sintering, and defects such as micropores and surface roughness are prone to appear inside and on the surface of the magnet, which will reduce the corrosion resistance of AlNiCo magnets. Therefore, after a lot of research and experimental verification, the applicant finally determined that the weight of corrosion-resistant components in this application should be as described above.
[0017] Preferably, the concentration of potassium dihydrogen phosphate is 50-90 g / L.
[0018] Preferably, the concentration of potassium dihydrogen phosphate is 75 g / L.
[0019] When the potassium dihydrogen phosphate content is low, the number of potassium ions may be insufficient to form a complete complex with the silicon-nitrogen bonds on the silicon nitride ceramic, resulting in low adhesion of the phosphating film and thus minimal improvement in the corrosion resistance of the AlNiCo magnet. Conversely, when the potassium dihydrogen phosphate content in the phosphating solution is too high, the potassium ion concentration in the solution becomes excessive. Excessive potassium ions may form excessive intermetallic compounds or potassium-rich phases in the phosphating film. These phases may reduce the hardness and wear resistance of the phosphating film, thereby reducing the corrosion resistance of the AlNiCo magnet.
[0020] Preferably, the high-temperature phosphating treatment time is 8-15 minutes.
[0021] By adopting the above technical solution, when the phosphating treatment time is too short, the phosphating reaction is insufficient, the concentration of film-forming ions does not reach the solubility product, resulting in a phosphating film that is too thin and difficult to form a dense protective layer; when the phosphating treatment time is too long, the phosphating reaction continues, resulting in a phosphating film that is too thick, the roughness increases, and the adhesion is affected. Therefore, after a lot of research and experimental verification, the applicant finally determined that the high-temperature phosphating treatment time of this application is as described above.
[0022] Secondly, this application provides an AlNiCo magnet, which adopts the following technical solution: An AlNiCo magnet is prepared by the above-described method for preparing AlNiCo magnets.
[0023] In summary, this application has the following beneficial effects: This application improves the corrosion resistance of AlNiCo magnets with added Tb and Dy by sintering corrosion-resistant components to generate silicon nitride ceramics. At the same time, the sintered AlNiCo magnets are subjected to phosphating treatment. The potassium ions in the phosphating solution react with the silicon nitride ceramics at high temperature to form a highly adhesive phosphating film, which further improves the corrosion resistance of the AlNiCo magnets, thereby preparing AlNiCo magnets. Detailed Implementation
[0024] The raw materials in this application include the following: Methylvinylsilazane: 1,1,3,3-tetramethyl-1,3-divinyldisilazane (hereinafter referred to as tetramethyldivinyldisilazane), 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasilazane, and tetramethyldivinyldisilazane are all acceptable options. This application uses tetramethyldivinyldisilazane with CAS number 7691-02-3 as an example.
[0025] Polysilazane resin: a commercially available product with CAS number 475645-84-2.
[0026] The present application will be further described in detail below with reference to embodiments and comparative examples.
[0027] Example 1 A method for preparing an AlNiCo magnet includes the following steps: Melting and spinning: 68g Al, 205g Ni, 9.5g Co, 50g Tb, 5g Dy, 15g Co, and 660g Fe are mixed and put into a vacuum melting furnace to melt, and the melt is cast and spun to obtain a spun sheet; Hydrogen-crushed grinding: The belt sheet is hydrogen-crushed into coarse powder, and the coarse powder is then passed through an air jet mill to obtain alloy powder. Press molding: The obtained alloy powder and 4g of polysilazane resin are placed in a mold and pressed to obtain a sintered green blank; Sintering process: The sintered green blank is sintered under nitrogen protection at a temperature of 1100℃ for 3 hours. After sintering, it is rapidly cooled to room temperature in stages and tempered to obtain an AlNiCo magnet. Phosphating treatment: After surface treatment of the AlNiCo magnet, heat 10L of phosphating solution to 93°C, then immerse the AlNiCo magnet in the phosphating solution for 12 minutes, and then take it out and rinse to obtain phosphated AlNiCo magnet.
[0028] The cooling process after sintering the green compact consists of three stages. In the first stage, the sintering temperature is reduced from 1100℃ to 800℃ at a cooling rate of 7℃ / min, and held for 3 hours. In the second stage, the sintering temperature is further reduced from 800℃ to room temperature at a rate of 4℃ / min. The tempering process consists of two stages. In the first stage, the tempering temperature is 800℃ and the tempering time is 2 hours. After the tempering is completed, argon gas is used to cool the magnetic material to room temperature. Then, the second stage of tempering begins, with a tempering temperature of 500℃ and a tempering time of 3 hours. After the tempering is completed, argon gas is used to cool the magnetic material to room temperature.
[0029] The surface treatment described above involves cleaning the AlNiCo magnets with an alkaline cleaning solution (a mixture of 100g / L potassium hydroxide solution and 50g sodium silicate solution, with a volume ratio of potassium hydroxide solution to sodium silicate solution = 1:3), followed by cleaning with alcohol and non-woven cloth, and finally air drying. Then, the cleaned AlNiCo magnets are immersed in molten potassium nitrate solution for 4 minutes, removed, dissolved in 35℃ water, rinsed, and dried.
[0030] The phosphating solution contains the following components at the following concentrations: potassium dihydrogen phosphate 75 g / L, phosphoric acid 150 g / L, and manganese nitrate 8 g / L.
[0031] Example 2-3 Examples 2-3 are based on the preparation method of Example 1, but the composition ratio of the AlNiCo magnet is adjusted as shown in Table 1.
[0032] Comparative Examples 1-4 Comparative Example 1 was prepared using the same method as in Example 1, but without the addition of 4g of polysilazane resin and without phosphating treatment, while keeping all other conditions unchanged.
[0033] Comparative Example 2 was prepared using the same method as Comparative Example 1, but without the addition of Tb and Dy, while keeping all other conditions unchanged.
[0034] Comparative Example 3 was prepared using the same method as in Example 1, but without the addition of 4g of polysilazane resin, while keeping all other conditions unchanged.
[0035] Comparative Example 4 was prepared using the same method as in Example 1, except that potassium dihydrogen phosphate in the phosphating solution was replaced with zinc dihydrogen phosphate, while all other conditions remained unchanged.
[0036] Performance testing The AlNiCo magnets of Examples 1-3 and Comparative Examples 1-4 were analyzed using the following specific testing methods: Magnetic properties The comprehensive magnetic properties of permanent magnet (hard magnet) materials were tested according to GCo / T3217-2013 "Magnetic Test Methods for Permanent Magnet (Hard Magnet) Materials".
[0037] Corrosion resistance A neutral salt spray test was conducted using a 5 wt% sodium chloride aqueous solution to spray the magnetic material samples at a temperature of 35°C. Since the corrosion reaction of AlNiCo magnets in neutral salt spray is primarily oxidation and exfoliation, the weight loss rate was used as the basis for assessing the corrosion resistance of the magnetic material samples. Weight loss rate = (mass before immersion - mass after immersion) / mass before immersion.
[0038] Based on the above detection method, the test results of Examples 1-3 and Comparative Examples 1-4 were obtained, as shown in Table 1 below: Table 1. Composition ratios and performance test results of AlNiCo magnets in Examples 1-3 and Comparative Examples 1-4 (unit: g) Referring to Table 1, comparing Examples 1-3 and Comparative Examples 1-4, it can be seen that, compared to Example 1 and Comparative Examples 1-2, the addition of heavy rare earth elements such as Tb and Dy to the formulation of AlNiCo magnets can significantly improve the intrinsic coercivity of the magnets. This is likely because Tb and Dy, as heavy rare earth elements, possess special magnetic properties in magnets, which can effectively enhance the intrinsic coercivity of the magnets.
[0039] Similarly, it can be observed that adding a significant amount of heavy rare earth elements (Tb and Dy) to the AlNiCo magnet formulation reduces the corrosion resistance of the magnet. This may be because when Tb and Dy partially replace neodymium, they further increase the density of the main Ni2Fe phase. 14The electrochemical potential difference between Co and neodymium-rich phases such as Ni-rich makes magnets more susceptible to corrosion in electrochemical environments.
[0040] Compared to Examples 1 and Comparative Examples 3-4, phosphating alone offers limited improvement in the corrosion resistance of AlNiCo magnets. Furthermore, replacing potassium dihydrogen phosphate with zinc dihydrogen phosphate in the phosphating solution also negatively impacts the corrosion resistance of AlNiCo magnets. This is likely because the polysilazane resin produces silicon nitride ceramics after sintering. These silicon nitride ceramics can cover the grain boundaries and surface of the AlNiCo magnets, forming a dense physical barrier. This barrier effectively inhibits the penetration of oxygen and corrosive media, thereby improving the magnet's corrosion resistance. In addition, potassium ions form coordination bonds with nitrogen atoms on the silicon nitride ceramic at 85-98°C, generating stable complexes. The resulting phosphating film has stronger adhesion, further protecting the magnet substrate from corrosive media and improving the corrosion resistance of the AlNiCo magnets.
[0041] Therefore, it is necessary to add heavy rare earth elements such as Tb and Dy to improve the intrinsic coercivity of AlNiCo magnets. Simultaneously, it is necessary to add corrosion-resistant components such as polysilazane resin and perform phosphating treatment. The phosphating solution includes potassium dihydrogen phosphate, which can significantly improve the corrosion resistance of AlNiCo magnets.
[0042] Comparing the intrinsic coercivity of Examples 1-3, Example 1 has the highest intrinsic coercivity and its corrosion resistance is basically equivalent to that of Example 2, so it is preferred.
[0043] Examples 4-7 Examples 4-6 are based on the preparation method of Example 1, but the amount of polysilazane resin added is adjusted, as shown in Table 2.
[0044] In Example 7, based on the preparation method of Example 1, in the pressing step, the obtained alloy powder and 4g of tetramethyldivinyldisilazane were placed in a mold and pressed to obtain a sintered green body.
[0045] Based on the above detection method, the test results of Examples 4-7 were obtained, as shown in Table 2 below.
[0046] Table 2 Performance test data for Examples 1 and 4-7 project Example 1 Example 4 Example 5 Example 6 Example 7 Polysilazane resin / g 4 2 5 6 / 96h weight loss rate / % 0.232 0.368 0.246 0.278 0.241 Referring to Table 2, a comparison of Examples 1 and 4-7 shows that the addition of tetramethyldivinyldisilazane or polysilazane resin can increase the corrosion resistance of AlNiCo magnets. This is likely because during the sintering process, methyldivinyldisilazane and polysilazane resin decompose under high-temperature conditions, producing silicon nitride ceramics. Simultaneously, silicon nitride ceramics can cover the grain boundaries and surface of the AlNiCo magnets, forming a dense physical barrier. This barrier effectively inhibits the penetration of oxygen and corrosive media, thereby significantly improving the corrosion resistance of the magnets.
[0047] In comparison, AlNiCo magnets with added polysilazane resin have better corrosion resistance than AlNiCo magnets with added tetramethyldivinyldisilazane. This may be because polysilazane resin releases less gas, resulting in fewer defects such as micropores and surface roughness inside and on the magnet, thus giving it higher corrosion resistance.
[0048] Examples 8-11 Examples 8-11 are based on the preparation method of Example 1, but the concentrations of each component of the phosphating solution are adjusted as shown in Table 3.
[0049] Comparative Example 5 Comparative Example 5, based on the preparation method of Example 1, adjusted the concentrations of each component of the phosphating solution to 10 g / L potassium dihydrogen phosphate, 350 g / L phosphoric acid, and 10 g / L potassium nitrate.
[0050] The performance tests of the AlNiCo magnets of Examples 8-11 and Comparative Example 5 were performed as described above, and the test results are shown in Table 3.
[0051] Table 3. Phosphating solution composition ratios and performance test data for Examples 1, 8-11, and Comparative Example 5. Referring to Table 3, comparing Examples 1, 8-11, and Comparative Example 5, it can be seen that as the concentration of potassium dihydrogen phosphate increases, the 96-hour weight loss rate of the AlNiCo magnets shows a trend of first increasing and then decreasing. This may be because as the concentration of potassium dihydrogen phosphate increases, the potassium ion content increases, gradually and fully forming complexes with the silicon-nitrogen bonds on the silicon nitride ceramic, thus gradually improving the adhesion of the phosphating film and continuously enhancing the corrosion resistance of the AlNiCo magnets. However, when the concentration exceeds a certain range, excessive potassium ions may form excessive intermetallic compounds or potassium-rich phases in the phosphating film. These phases may reduce the hardness and wear resistance of the phosphating film, thereby reducing the corrosion resistance of the AlNiCo magnets.
[0052] Compared to Examples 1, 8, and Comparative Example 5, the 96-hour weight loss rate of Comparative Example 5 was significantly greater than that of Examples 1 and 8. Manganese ions can improve the hardness and adhesion of the phosphating film. However, the absence of manganese ions in the solution may lead to changes in the composition and structure of the phosphating film, affecting its formation rate and density, thereby reducing the corrosion resistance of the AlNiCo magnet.
[0053] Examples 12-13 Examples 12-13 are based on the preparation method of Example 1, but the heating temperature in the phosphating step is adjusted. The specific adjustments are shown in Table 4.
[0054] Comparative Examples 6-7 Comparative Examples 6-7 are based on the preparation method of Example 1, but the heating temperature in the phosphating step is adjusted. The specific adjustments are shown in Table 4.
[0055] The performance tests of the AlNiCo magnets of Examples 12-13 were performed as described above, and the test results are shown in Table 4.
[0056] Table 4. Heating temperature and performance test data for Examples 1, 12-13, and Comparative Examples 6-7. project Example 1 Example 12 Example 13 Comparative Example 6 Comparative Example 7 Temperature / °C 93 85 98 80 105 96h weight loss rate / % 0.232 0.336 0.293 0.436 0.507 Referring to Table 4, comparing Examples 1, 12-13 and 6-7, it can be seen that as the heating temperature during phosphating treatment continuously increases, the 96-hour weight loss rate of AlNiCo magnets shows a trend of first increasing and then decreasing. This may be because as the heating temperature during phosphating treatment continuously increases, potassium ions and silicon nitride ceramics formed by polysilazane resin continuously form coordination bonds, enhancing the adhesion of the phosphating film and thus enhancing the corrosion resistance of AlNiCo magnets. However, when the temperature exceeds a certain range, excessively high temperatures may cause the phosphating film structure to become loose, thereby reducing the corrosion resistance of AlNiCo magnets.
[0057] Examples 14-17 Examples 14-17 are based on the preparation method of Example 1, but the phosphating time in the phosphating step is adjusted. The specific adjustments are shown in Table 5.
[0058] The performance tests of the AlNiCo magnets in Examples 14-17 were performed as described above, and the test results are shown in Table 5.
[0059] Table 5. Phosphating treatment time and performance test data for Examples 1 and 14-17 project Example 1 Example 14 Example 15 Example 16 Example 17 Time / min 12 6 8 15 20 96h weight loss rate / % 0.232 0.389 0.338 0.264 0.351 Referring to Table 5, a comparison of Examples 1 and 14-17 shows that as the phosphating time increases, the 96-hour weight loss rate of AlNiCo magnets first increases and then decreases. This may be because as the phosphating time increases, the phosphating reaction becomes more complete, forming a dense protective layer, thereby enhancing the corrosion resistance of AlNiCo magnets. When a certain range is exceeded, the phosphating reaction continues, resulting in an excessively thick phosphating film, increased roughness, and reduced adhesion, thus decreasing the corrosion resistance of AlNiCo magnets.
[0060] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A method for preparing an AlNiCo magnet, characterized in that, Includes the following steps: Melt casting: Metal raw materials are mixed according to the formula and the mixture is melted to obtain a molten liquid. The molten liquid is then cast into a strip to obtain a cast strip. Hydrogen-crushed grinding: The belt sheet is hydrogen-crushed into coarse powder, and the coarse powder is then passed through an air jet mill to obtain alloy powder. Press molding: The obtained alloy powder and corrosion-resistant components are placed in a mold and pressed to obtain a sintered green body; Sintering process: The green blank is sintered under nitrogen protection. After sintering, it is rapidly cooled to room temperature in stages and tempered to obtain AlNiCo magnets. Phosphating treatment: After surface treatment of the AlNiCo magnet, it is immersed in phosphating solution for high-temperature phosphating treatment, and then taken out and rinsed to obtain phosphated AlNiCo magnet; The metal raw material comprises the following components in parts by weight: Al 6.5-7 parts, Ni 19.5-21 parts, Co 0.90-1.03 parts, Tb 4-6 parts, Dy 0-1 parts, Co 1-2 parts, Fe 64-68 parts; The corrosion-resistant component includes at least one of methyl vinyl silazane and polysilazane resin; The phosphating solution comprises the following components at the following concentrations: potassium dihydrogen phosphate 30-100 g / L, phosphoric acid 100-200 g / L, and manganese nitrate 5-10 g / L; The temperature range for the high-temperature phosphating treatment is 85-98℃.
2. The method for preparing the AlNiCo magnet according to claim 1, characterized in that: The corrosion-resistant component is polysilazane resin.
3. The method for preparing the AlNiCo magnet according to claim 1, characterized in that: The corrosion-resistant component is present in an amount of 0.2-0.5 parts by weight.
4. The method for preparing the AlNiCo magnet according to claim 3, characterized in that: The corrosion-resistant component is 0.4 parts by weight.
5. The method for preparing an AlNiCo magnet according to claim 1, characterized in that: The concentration of potassium dihydrogen phosphate is 50-90 g / L.
6. The method for preparing an AlNiCo magnet according to claim 5, characterized in that: The concentration of potassium dihydrogen phosphate is 75 g / L.
7. The method for preparing an AlNiCo magnet according to claim 1, characterized in that: The high-temperature phosphating treatment takes 8-15 minutes.
8. An AlNiCo magnet, characterized in that: It is prepared by the method for preparing AlNiCo magnets according to any one of claims 1-7.