Corrosion-resistant powerful magnet material and preparation method thereof

Abstract

The invention relates to the technical field of magnets, in particular to an anti-corrosion powerful magnet material and a preparation method thereof.The anti-corrosion powerful magnet material comprises a magnetic matrix and a high-molecular polymer which is filled in pores of the magnetic matrix and wraps the surface of the magnetic matrix; the magnetic matrix comprises the following raw material components in percentage by mass: 40%-50% of neodymium iron boron powder, 5%-10% of nano-copper, 3%-7% of nano-zinc, 5%-8% of nano-cobalt, 1%-5% of nano-zirconium, 5%-8% of nano-zinc oxide, 6%-10% of nano-silicon dioxide and the balance of nano-iron. The magnet material disclosed by the invention has good magnetism and corrosion resistance.

Description

Technical Field

[0001] The invention relates to the technical field of magnets, and in particular to a corrosion-resistant strong magnet material and a preparation method thereof. Background Art

[0002] NdFeB magnets are the magnets with the highest commercial performance found so far. They are small in size, light in weight and have strong magnetism. They are called "magnet king" and are widely used in electronics, power machinery, medical equipment, toys, packaging, hardware machinery, aerospace and other fields. The more common ones are permanent magnet motors, speakers, magnetic separators, computer disk drives, magnetic resonance imaging equipment and instruments, etc. With the development of science and technology and the progress of society, people have higher and higher requirements for the performance of NdFeB magnets. Since NdFeB magnets are made of rare earth metal neodymium, pure iron and boron by powder metallurgy, their surface is relatively loose and porous, and they are prone to oxidation and rust in the use environment. In addition, they will suffer severe electrochemical corrosion under hot and humid conditions, which will deteriorate the magnetic properties and greatly reduce their service life. Summary of the invention

[0003] The invention provides a corrosion-resistant strong magnet material and a preparation method thereof, which solves the technical problem that the existing NdFeB magnet has poor corrosion resistance.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions: A corrosion-resistant strong magnet material, comprising a magnetic matrix and a high molecular polymer filled in the pores of the magnetic matrix and wrapped on the surface of the magnetic matrix; The magnetic matrix includes the following raw material components in mass percentage: NdFeB powder 40%-50%, nano copper 5%-10%, nano zinc 3%-7%, nano cobalt 5%-8%, nano zirconium 1%-5%, nano zinc oxide 5%-8%, nano silicon dioxide 6%-10%, and the balance is nano iron.

[0005] The method for preparing the above-mentioned corrosion-resistant strong magnet material comprises the following preparation steps: Step 1, after weighing the raw materials according to the raw material ratio of the magnetic matrix, NdFeB powder, nano copper, nano zinc, nano cobalt, nano zirconium, nano zinc oxide, nano silicon dioxide and nano iron are evenly mixed, put into a smelting furnace, continuously heat until all the raw materials are melted into liquid, and then cool until solidified to obtain a rough magnetic matrix; Step 2: grinding the rough magnetic matrix product to obtain magnetic matrix powder; Step 3, placing the magnetic matrix powder obtained in step 2 in a magnetic field under the action of an inert gas shielding gas for orientation molding, and then forming a blank by static pressing; Step 4: Place the blank in a vacuum environment at 700-900°C for primary tempering for 1-1.5 hours, then heat to 1000-1200°C for secondary tempering for 0.5-1.5 hours to obtain a magnetic matrix; Step 5. Add methyltetrahydrophthalic anhydride, epoxy monomer and organic solvent into the reactor and mix them evenly. Then put the magnetic matrix into the reactor so that the magnetic matrix is ​​completely immersed in the mixed solution. Vibrate the solution and control the pressure in the reactor to 100-150MPa and the temperature to 50-60°C. After reacting for 6-7h, take out the magnetic matrix and obtain a corrosion-resistant strong magnet material after drying.

[0006] Furthermore, in step one, the mixing method of the magnetic matrix raw material is to first stir the raw material by mechanical stirring at a speed of 200-400 r / min for 2-3 hours, and then process the raw material by ball milling at a ball-to-material ratio of 10-20:1, a rotation speed of 280 r / min-320 r / min, and a ball milling time of 2-3 hours.

[0007] Furthermore, in step one, the heating temperature is 2000-2500° C., and the heating time is 2-3 hours.

[0008] Furthermore, in step 2, a tube mill is used for continuous grinding for 6-7 hours to obtain a magnetic matrix powder with a particle size of 100-200 nm.

[0009] Furthermore, in step three, the magnetic field strength is 20000Gs-25000Gs, and the static pressure is 400-450MPa.

[0010] Furthermore: in step five, the epoxy monomer is at least one of propylene oxide, ethylene oxide, and butylene oxide.

[0011] Furthermore, in step five, the mass ratio of the methyltetrahydrophthalic anhydride, the epoxy monomer and the organic solvent is 1-2:20-30:50-60.

[0012] Furthermore, in step five, the vibration frequency is 25-55 Hz, the vibration amplitude is 10-15 mm, and the vibration time is 20-60 min.

[0013] Beneficial effects of the present invention: The magnetic matrix of the present invention is composed of NdFeB powder, nano copper, nano zinc, nano cobalt, nano zirconium, nano zinc oxide, nano silicon dioxide and nano iron, and the mass ratio of each raw material component is strictly controlled to regulate the intercrystalline structure, ensure the uniform distribution of each phase, and at the same time, the grain size is small and the structure is more compact, so that the pores in the magnetic matrix are smaller, and the corrosion products are more likely to block the pores, thereby blocking corrosion and improving the corrosion resistance of the magnetic matrix. On the other hand, the present invention further achieves the purpose of corrosion resistance by filling the pores of the magnetic matrix with high molecular polymers and wrapping the high molecular polymers on the surface of the magnetic matrix to block the diffusion channels of the corrosive medium.

[0014] The preparation method of the present invention comprises the following steps: firstly mixing the raw material components of the magnetic matrix and then melting them, then cooling and solidifying them, then grinding them into powder, then orienting and molding them in a magnetic field and statically pressing them into blanks, and finally performing two tempering treatments to obtain the magnetic matrix. The obtained magnetic matrix has higher density and corrosion resistance. The preparation method of the present invention also includes immersing the magnetic substrate in a mixed solution containing methyltetrahydrophthalic anhydride, epoxy monomers and an organic solvent, and adopting technical means of vibrating the solution and controlling the pressure in the reactor. During the vibration process, the reagents in the mixed solution will enter the pores of the magnetic substrate and adhere to the surface of the magnetic substrate. Controlling the pressure in the reactor to 100-150MPa is conducive to squeezing more reaction reagents into the pores of the magnetic substrate. Then, the temperature in the reactor is controlled to 50-60°C, so that the epoxy monomers undergo polymerization reaction to generate high-molecular epoxy polymers, and then the pores of the magnetic substrate are blocked by the high-molecular epoxy polymers, and the surface of the magnetic substrate is coated with a high-molecular epoxy polymer layer, so that media such as oxygen and water can no longer enter the interior of the magnetic substrate through the pores of the magnetic substrate to induce a corrosion reaction of the magnetic substrate, thereby effectively improving the corrosion resistance of the magnet material. Since the pores of the magnetic matrix made of the raw material components of the magnetic matrix of the present invention are very small, the present invention subsequently uses epoxy monomers with smaller molecular weights to mix with other reaction reagents, and uses the method of pressurizing and vibrating the solution to allow the reaction reagents to fully enter the pores of the magnetic matrix. Subsequently, the temperature is controlled to allow the epoxy monomers to undergo polymerization to generate macromolecular substances, which can achieve the purpose of blocking the channels of the corrosive medium from inside the magnetic matrix to achieve an anti-corrosion effect. Compared with the method of directly placing the magnetic matrix into a polymer solution, since the polymer substance is larger in volume and more difficult to enter the pores of the magnetic matrix, it is difficult to achieve the anti-corrosion effect of the present invention by directly mixing the polymer with the magnetic matrix. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical scheme and technical effect of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention is clearly and completely described. The embodiments described below are part of the embodiments of the present invention, rather than all of the embodiments. In conjunction with the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer; if the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0016] In the description of the present invention, the term "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0017] In the description of the present invention, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0018] It should be understood that the weight of the relevant components mentioned in the embodiments of the present invention can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components in the embodiments of the present invention is proportionally enlarged or reduced, it is within the scope disclosed by the present invention. Specifically, the weight described in the embodiments of the present invention can be a mass unit known in the chemical industry such as μg, mg, g, kg, etc.

[0019] In addition, unless the context clearly uses otherwise, the expression of the singular form of a word should be understood to include the plural form of the word. The term "includes" or "having" is intended to specify the existence of a feature, quantity, step, operation, element, part or combination thereof, but is not used to exclude the existence or possible addition of one or more other features, quantities, steps, operations, elements, parts or combinations thereof.

[0020] An embodiment of the present invention provides a corrosion-resistant strong magnet material, which includes a magnetic matrix and a high molecular polymer filled in the pores of the magnetic matrix and wrapped on the surface of the magnetic matrix; The magnetic matrix includes the following raw material components in mass percentage: NdFeB powder 40%-50%, nano copper 5%-10%, nano zinc 3%-7%, nano cobalt 5%-8%, nano zirconium 1%-5%, nano zinc oxide 5%-8%, nano silicon dioxide 6%-10%, and the balance is nano iron.

[0021] Since NdFeB magnetic materials have a porous and uneven organizational structure, the organizational structure causes NdFeB magnetic materials to be prone to corrosion. In order to solve this technical problem, the magnetic matrix of the present invention is composed of NdFeB powder, nano copper, nano zinc, nano cobalt, nano zirconium, nano zinc oxide, nano silicon dioxide, and nano iron. The mass ratio of each raw material component is strictly controlled to regulate the intercrystalline structure and ensure uniform distribution of each phase. At the same time, the grain size is small and the structure is more compact, so that the pores in the magnetic matrix are smaller, and the corrosion products are more likely to block the pores, thereby blocking corrosion and improving the corrosion resistance of the magnetic matrix. On the other hand, the present invention further achieves the purpose of corrosion resistance by filling the pores of the magnetic matrix with high molecular polymers and wrapping the surface of the magnetic matrix with high molecular polymers to block the diffusion channels of the corrosive medium.

[0022] The method for preparing the above-mentioned corrosion-resistant strong magnet material comprises the following preparation steps: Step 1, after weighing the raw materials according to the raw material ratio of the magnetic matrix, NdFeB powder, nano copper, nano zinc, nano cobalt, nano zirconium, nano zinc oxide, nano silicon dioxide and nano iron are evenly mixed, put into a smelting furnace, continuously heat until all the raw materials are melted into liquid, and then cool until solidified to obtain a rough magnetic matrix; Step 2: grinding the rough magnetic matrix product to obtain magnetic matrix powder; Step 3, placing the magnetic matrix powder obtained in step 2 in a magnetic field under the action of an inert gas shielding gas for orientation molding, and then forming a blank by static pressing; Step 4: Place the blank in a vacuum environment at 700-900°C for primary tempering for 1-1.5 hours, then heat to 1000-1200°C for secondary tempering for 0.5-1.5 hours to obtain a magnetic matrix; Step 5. Add methyltetrahydrophthalic anhydride, epoxy monomer and organic solvent into the reactor and mix them evenly. Then put the magnetic matrix into the reactor so that the magnetic matrix is ​​completely immersed in the mixed solution. Vibrate the solution and control the pressure in the reactor to 100-150MPa and the temperature to 50-60°C. After reacting for 6-7h, take out the magnetic matrix and obtain a corrosion-resistant strong magnet material after drying.

[0023] The present invention mixes raw material components of the magnetic matrix and then melts them, cools and solidifies them, grinds them into powder, then orients them in a magnetic field and statically presses them into blanks, and finally obtains the magnetic matrix through two tempering treatments. The obtained magnetic matrix has higher density and corrosion resistance. The preparation method of the present invention also includes immersing the magnetic substrate in a mixed solution containing methyltetrahydrophthalic anhydride, epoxy monomers and an organic solvent, and adopting technical means of vibrating the solution and controlling the pressure in the reactor. During the vibration process, the reagents in the mixed solution will enter the pores of the magnetic substrate and adhere to the surface of the magnetic substrate. Controlling the pressure in the reactor to 100-150MPa is conducive to squeezing more reaction reagents into the pores of the magnetic substrate. Then, the temperature in the reactor is controlled to 50-60°C, so that the epoxy monomers undergo polymerization reaction to generate high-molecular epoxy polymers, and then the pores of the magnetic substrate are blocked by the high-molecular epoxy polymers, and the surface of the magnetic substrate is coated with a high-molecular epoxy polymer layer, so that media such as oxygen and water can no longer enter the interior of the magnetic substrate through the pores of the magnetic substrate to induce a corrosion reaction of the magnetic substrate, thereby effectively improving the corrosion resistance of the magnet material. Since the pores of the magnetic matrix made of the raw material components of the magnetic matrix of the present invention are very small, the present invention subsequently uses epoxy monomers with smaller molecular weights to mix with other reaction reagents, and uses the method of pressurizing and vibrating the solution to allow the reaction reagents to fully enter the pores of the magnetic matrix. Subsequently, the temperature is controlled to allow the epoxy monomers to undergo polymerization to generate macromolecular substances, which can achieve the purpose of blocking the channels of the corrosive medium from inside the magnetic matrix to achieve an anti-corrosion effect. Compared with the method of directly placing the magnetic matrix into a polymer solution, since the polymer substance is larger in volume and more difficult to enter the pores of the magnetic matrix, it is difficult to achieve the anti-corrosion effect of the present invention by directly mixing the polymer with the magnetic matrix.

[0024] Furthermore, in step one, the mixing method of the magnetic matrix raw material is to first stir the raw material by mechanical stirring at a speed of 200-400 r / min for 2-3 hours, and then process the raw material by ball milling at a ball-to-material ratio of 10-20:1, a rotation speed of 280 r / min-320 r / min, and a ball milling time of 2-3 hours.

[0025] The present invention mechanically stirs the magnetic matrix raw material powder first and then ball mills it, and controls the stirring speed, the ball-to-material ratio and the ball milling speed, so that the raw material powder can be mixed more evenly, the density of the prepared magnet material is higher, and the corrosion resistance of the magnet material is improved, and the magnetic property is better.

[0026] Furthermore, in step one, the heating temperature is 2000-2500° C., and the heating time is 2-3 hours.

[0027] Furthermore, in step 2, a tube mill is used to grind continuously for 6-7 hours to obtain a magnetic matrix powder with a particle size of 100-200 nm. By grinding the magnetic matrix powder to 100-200 nm, it is more conducive to improving the density of the magnet material, and ultimately improving the anti-corrosion performance and magnetic properties of the magnet material.

[0028] Furthermore, in step three, the magnetic field strength is 20000Gs-25000Gs, and the static pressure is 400-450MPa.

[0029] Furthermore: in step five, the epoxy monomer is at least one of propylene oxide, ethylene oxide, and butylene oxide.

[0030] Furthermore, in step five, the mass ratio of the methyltetrahydrophthalic anhydride, the epoxy monomer and the organic solvent is 1-2:20-30:50-60.

[0031] Furthermore, in step 5, the vibration frequency is 25-55 Hz, the vibration amplitude is 10-15 mm, and the vibration time is 20-60 min. By controlling the vibration frequency and the vibration amplitude, it is more conducive to the reaction reagent to enter the pores of the magnetic matrix, so that the epoxy monomer can undergo polymerization reaction in the pores of the magnetic matrix to generate macromolecular epoxy polymers to block the pores of the magnetic matrix, thereby blocking the corrosion channel of the magnetic matrix and achieving an anti-corrosion effect.

[0032] In order to enable those skilled in the art to clearly understand the implementation details and operations of the present invention, and to significantly demonstrate the improved performance of the embodiments of the present invention, the above technical solutions are illustrated by multiple embodiments below.

[0033] Example 1 A corrosion-resistant strong magnet material comprises a magnetic matrix and a high molecular polymer filled in the pores of the magnetic matrix and wrapped on the surface of the magnetic matrix; the magnetic matrix comprises the following raw material components in mass percentage: 40% neodymium iron boron powder, 5% nano copper, 3% nano zinc, 5% nano cobalt, 1% nano zirconium, 5% nano zinc oxide, 6% nano silicon dioxide, and the balance is nano iron.

[0034] The method for preparing the above-mentioned corrosion-resistant strong magnet material comprises the following preparation steps: Step 1, after weighing the raw materials according to the raw material ratio of the magnetic matrix, NdFeB powder, nano copper, nano zinc, nano cobalt, nano zirconium, nano zinc oxide, nano silicon dioxide and nano iron are mixed, the raw materials are first stirred by mechanical stirring at a stirring speed of 200r / min for 3h, and then the raw materials are processed by ball milling at a ball-to-material ratio of 10:1, a ball milling speed of 320r / min, and a ball milling time of 3h to mix the raw materials evenly, and then put them into a melting furnace, and continue to heat and heat until all the raw materials are melted into liquid, the heating temperature is 2000℃, the heating time is 3h, and then cooled to solidify to obtain a rough magnetic matrix; Step 2: grinding the coarse magnetic matrix product continuously for 6 hours using a tube mill to obtain a magnetic matrix powder with an average particle size of 100 nm; Step 3: Place the magnetic matrix powder obtained in step 2 in a magnetic field with a magnetic field strength of 20000 Gs under the action of argon protective gas for orientation molding, and then statically press it into a blank at a pressure of 400 MPa; Step 4: Place the blank in a vacuum environment at 700°C for primary tempering for 1.5 hours, then heat to 1000°C for secondary tempering for 1.5 hours to obtain a magnetic matrix; Step 5. Add methyltetrahydrophthalic anhydride, propylene oxide and ethanol into the reactor in a mass ratio of 1:20:50 and mix evenly. Then put the magnetic matrix into the reactor so that the magnetic matrix is ​​completely immersed in the mixed solution. Vibrate the solution with a vibration frequency of 25 Hz, a vibration amplitude of 10 mm, and a vibration time of 60 min. Control the pressure in the reactor to 100 MPa and the temperature to 50 ° C. After reacting for 7 hours, take out the magnetic matrix and obtain a corrosion-resistant strong magnet material after drying.

[0035] Example 2 A corrosion-resistant strong magnet material comprises a magnetic matrix and a high molecular polymer filled in the pores of the magnetic matrix and wrapped on the surface of the magnetic matrix; the magnetic matrix comprises the following raw material components in percentage by mass: 45% of neodymium iron boron powder, 7.5% of nano copper, 5% of nano zinc, 6.5% of nano cobalt, 3% of nano zirconium, 6.5% of nano zinc oxide, 8% of nano silicon dioxide, and the balance is nano iron.

[0036] The method for preparing the above-mentioned corrosion-resistant strong magnet material comprises the following preparation steps: Step 1, after weighing the raw materials according to the raw material ratio of the magnetic matrix, NdFeB powder, nano copper, nano zinc, nano cobalt, nano zirconium, nano zinc oxide, nano silicon dioxide and nano iron are mixed, the raw materials are first stirred by mechanical stirring at a stirring speed of 300 r / min for 2.5 hours, and then the raw materials are processed by ball milling at a ball-to-material ratio of 15:1, a ball milling speed of 300 r / min, and a ball milling time of 2.5 hours to mix the raw materials evenly, and then put them into a melting furnace, continue to heat and heat until all the raw materials are melted into liquid, the heating temperature is 2250°C, the heating time is 2.5 hours, and then cooled to solidify to obtain a rough magnetic matrix; Step 2: Grind the coarse magnetic matrix product continuously for 6.5 hours using a tube mill to obtain a magnetic matrix powder with an average particle size of 150 nm; Step 3: Place the magnetic matrix powder obtained in step 2 in a magnetic field with a magnetic field strength of 22500 Gs under the action of argon protective gas for orientation molding, and then statically press the powder into a blank at a pressure of 425 MPa; Step 4: Place the blank in a vacuum environment at 800°C for primary tempering for 1.25 hours, then heat to 1100°C for secondary tempering for 1.25 hours to obtain a magnetic matrix; Step 5. Add methyltetrahydrophthalic anhydride, ethylene oxide and ethanol into the reactor in a mass ratio of 1.5:25:55 and mix evenly. Then put the magnetic matrix into the reactor so that the magnetic matrix is ​​completely immersed in the mixed solution. Vibrate the solution with a vibration frequency of 40 Hz, a vibration amplitude of 12.5 mm, and a vibration time of 40 min. Control the pressure in the reactor to 125 MPa and the temperature to 55 ° C. After reacting for 6.5 hours, take out the magnetic matrix and obtain a corrosion-resistant strong magnet material after drying.

[0037] Example 3 A corrosion-resistant strong magnet material comprises a magnetic matrix and a high molecular polymer filled in the pores of the magnetic matrix and wrapped on the surface of the magnetic matrix; the magnetic matrix comprises the following raw material components in mass percentage: 50% neodymium iron boron powder, 10% nano copper, 7% nano zinc, 8% nano cobalt, 5% nano zirconium, 8% nano zinc oxide, 10% nano silicon dioxide, and the balance is nano iron.

[0038] The method for preparing the above-mentioned corrosion-resistant strong magnet material comprises the following preparation steps: Step 1, after weighing the raw materials according to the raw material ratio of the magnetic matrix, NdFeB powder, nano copper, nano zinc, nano cobalt, nano zirconium, nano zinc oxide, nano silicon dioxide and nano iron are mixed, the raw materials are first stirred by mechanical stirring at a stirring speed of 400r / min for 2h, and then the raw materials are processed by ball milling at a ball-to-material ratio of 20:1, a ball milling speed of 280r / minr / min, and a ball milling time of 2h to mix the raw materials evenly, and then put them into a melting furnace, continue to heat and heat until all the raw materials are melted into liquid, the heating temperature is 2500℃, the heating time is 2h, and then cooled to solidify to obtain a rough magnetic matrix; Step 2: grinding the coarse magnetic matrix product continuously for 7 hours using a tube mill to obtain a magnetic matrix powder with an average particle size of 200 nm; Step 3: Place the magnetic matrix powder obtained in step 2 in a magnetic field with a magnetic field strength of 25000 Gs under the action of argon protective gas for orientation molding, and then statically press the powder into a blank at a pressure of 450 MPa; Step 4: Place the blank in a vacuum environment at 900°C for primary tempering for 1 hour, then heat to 1200°C for secondary tempering for 0.5 hour to obtain a magnetic matrix; Step 5. Add methyltetrahydrophthalic anhydride, butylene oxide and ethanol into the reactor in a mass ratio of 2:30:60 and mix them evenly. Then put the magnetic matrix into the reactor so that the magnetic matrix is ​​completely immersed in the mixed solution. Vibrate the solution with a vibration frequency of 55 Hz, a vibration amplitude of 15 mm, and a vibration time of 20 min. Control the pressure in the reactor to 150 MPa and the temperature to 60 ° C. After reacting for 6 hours, take out the magnetic matrix and obtain a corrosion-resistant strong magnet material after drying.

[0039] Comparative Example 1 A method for preparing a magnet material. The difference between the preparation method of comparative example 1 and the preparation method of embodiment 2 is that the preparation method of comparative example 1 does not include step five, that is, the magnet material prepared in comparative example 1 is the magnetic matrix of embodiment 2, and the other steps and conditions of comparative example 1 are the same as those of embodiment 2, which are not repeated here.

[0040] Comparative Example 2 A method for preparing a magnetic material. The difference between the preparation method of comparative example 2 and embodiment 2 is that step five of comparative example 2 is: adding methyltetrahydrophthalic anhydride, ethylene oxide and ethanol into a reactor at a mass ratio of 1.5:25:55 and mixing them evenly, then placing a magnetic matrix into the reactor so that the magnetic matrix is ​​completely immersed in the mixed solution, and controlling the temperature in the reactor to be 55°C. After reacting for 6.5 hours, taking out the magnetic matrix and obtaining the magnetic material after drying.

[0041] Steps 1 to 4 of Comparative Example 2 are the same as those of Example 2 and are not described in detail here.

[0042] Comparative Example 3 A magnetic material. The difference between the magnetic material of comparative example 3 and embodiment 2 is that the magnetic material of comparative example 3 includes a magnetic matrix and a high molecular polymer filled in the pores of the magnetic matrix and wrapped on the surface of the magnetic matrix; the magnetic matrix includes the following raw material components in percentage by mass: 45% neodymium iron boron powder, 7.5% nano copper, 6.5% nano cobalt, 3% nano zirconium, 8% nano silicon dioxide, and the balance is nano iron.

[0043] The difference between the preparation method of the magnetic material of Comparative Example 3 and the preparation method of Example 2 lies in step one. Step one of Comparative Example 3 is: after weighing the raw materials according to the raw material ratio of the magnetic matrix, mix the neodymium iron boron powder, nano copper, nano cobalt, nano zirconium, nano silicon dioxide and nano iron, first stir the raw materials by mechanical stirring at a speed of 300 r / min for 2.5 hours, then process the raw materials by ball milling, the ball-to-material ratio is 15:1, the speed during ball milling is 300 r / min, the ball milling time is 2.5 hours, so that the raw materials are evenly mixed, and then put into a smelting furnace, continuously heated until all the raw materials are melted into liquid, the heating temperature is 2250°C, the heating time is 2.5 hours, and then cooled to solidify to obtain a crude magnetic matrix.

[0044] Steps 2 to 5 of Comparative Example 3 are the same as those of Example 2 and are not described in detail here.

[0045] Performance Testing Magnetic testing: The magnetic materials prepared by the preparation methods of Examples 1-3 and Comparative Examples 1-3 were tested with reference to GB / T3217-2013 "Magnetic Test Methods for Permanent Magnetic (Hard Magnetic) Materials"; Corrosion resistance test: The magnetic materials prepared by the preparation methods of Examples 1-3 and Comparative Examples 1-3 were immersed in a sodium chloride aqueous solution with a concentration of 50 g / L for a neutral salt spray test. The test temperature was 30°C. After the immersion, the weight loss rate of the magnetic material was calculated. Weight loss rate = (mass before immersion - mass after immersion) / mass before immersion.

[0046] Table 1 Magnetic material performance test results It can be seen from the test results in Table 1 that the magnet material prepared by the preparation method of the present invention has better magnetism and corrosion resistance.

[0047] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A corrosion-resistant strong magnet material, characterized in that: It includes a magnetic matrix and a high molecular polymer filled in the pores of the magnetic matrix and wrapped on the surface of the magnetic matrix; The magnetic matrix includes the following raw material components in mass percentage: NdFeB powder 40%-50%, nano copper 5%-10%, nano zinc 3%-7%, nano cobalt 5%-8%, nano zirconium 1%-5%, nano zinc oxide 5%-8%, nano silicon dioxide 6%-10%, and the balance is nano iron.

2. The method for preparing a corrosion-resistant strong magnet material according to claim 1, characterized in that: The method comprises the following preparation steps: Step 1, after weighing the raw materials according to the raw material ratio of the magnetic matrix, NdFeB powder, nano copper, nano zinc, nano cobalt, nano zirconium, nano zinc oxide, nano silicon dioxide and nano iron are evenly mixed, put into a smelting furnace, continuously heat until all the raw materials are melted into liquid, and then cool until solidified to obtain a rough magnetic matrix; Step 2: grinding the rough magnetic matrix product to obtain magnetic matrix powder; Step 3, placing the magnetic matrix powder obtained in step 2 in a magnetic field under the action of an inert gas shielding gas for orientation molding, and then forming a blank by static pressing; Step 4: Place the blank in a vacuum environment at 700-900°C for primary tempering for 1-1.5 hours, then heat to 1000-1200°C for secondary tempering for 0.5-1.5 hours to obtain a magnetic matrix; Step 5. Add methyltetrahydrophthalic anhydride, epoxy monomer and organic solvent into the reactor and mix them evenly. Then put the magnetic matrix into the reactor so that the magnetic matrix is ​​completely immersed in the mixed solution. Vibrate the solution and control the pressure in the reactor to 100-150MPa and the temperature to 50-60°C. After reacting for 6-7h, take out the magnetic matrix and obtain a corrosion-resistant strong magnet material after drying.

3. The method for preparing a corrosion-resistant strong magnet material according to claim 2, characterized in that: In step one, the mixing method of the magnetic matrix raw materials is to first stir the raw materials by mechanical stirring at a speed of 200-400r / min for 2-3h, and then process the raw materials by ball milling at a ball-to-material ratio of 10-20:1, a rotation speed of 280r / min-320r / min, and a ball milling time of 2-3h.

4. The method for preparing a corrosion-resistant strong magnet material according to claim 2, characterized in that: In step 1, the heating temperature is 2000-2500° C. and the heating time is 2-3 hours.

5. The method for preparing a corrosion-resistant strong magnet material according to claim 2, characterized in that: In step 2, a tube mill is used to continuously grind for 6-7 hours to obtain a magnetic matrix powder with a particle size of 100-200 nm.

6. The method for preparing a corrosion-resistant strong magnet material according to claim 2, characterized in that: The magnetic field strength in step three is 20000Gs-25000Gs, and the static pressure is 400-450MPa.

7. The method for preparing a corrosion-resistant strong magnet material according to claim 2, characterized in that: In step five, the epoxy monomer is at least one of propylene oxide, ethylene oxide, and butylene oxide.

8. The method for preparing a corrosion-resistant strong magnet material according to claim 2, characterized in that: In step 5, the mass ratio of the methyltetrahydrophthalic anhydride, the epoxy monomer and the organic solvent is 1-2:20-30:50-60.

9. The method for preparing a corrosion-resistant strong magnet material according to claim 2, characterized in that: In step five, the vibration frequency is 25-55 Hz, the vibration amplitude is 10-15 mm, and the vibration time is 20-60 min.

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