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CN-120511132-B - Antioxidant neodymium-iron-boron magnet and preparation method thereof

CN120511132BCN 120511132 BCN120511132 BCN 120511132BCN-120511132-B

Abstract

The invention relates to an antioxidant neodymium-iron-boron magnet and a preparation method thereof, wherein the antioxidant neodymium-iron-boron magnet comprises a neodymium-iron-boron substrate and a protective coating coated on the outer surface of the neodymium-iron-boron substrate, the protective coating is prepared from a protective coating, the protective coating comprises, by weight, 80-90 parts of bisphenol A type epoxy resin, 40-50 parts of solvent, 10-15 parts of organic silicon resin, 6-9 parts of PVDF resin, 11-15 parts of inorganic filler, 6-10 parts of zinc powder, 5-10 parts of zirconium isopropoxide, 4-7 parts of styrene-acrylonitrile-glycidyl methacrylate copolymer, 2-4 parts of silane coupling agent, 7-11 parts of graphene and 2-4 parts of hydroxypropyl methyl cellulose, and the component B comprises a curing agent. The protective coating is tightly combined with the NdFeB matrix, so that the oxidation resistance and corrosion resistance of the NdFeB magnet are improved, and the service life of the NdFeB magnet is prolonged.

Inventors

  • ZHAO CHUNHU

Assignees

  • 广东华九新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20250610

Claims (9)

  1. 1. The anti-oxidation neodymium-iron-boron magnet is characterized by comprising a neodymium-iron-boron substrate and a protective coating coated on the outer surface of the neodymium-iron-boron substrate, wherein the protective coating is prepared from a protective coating, the protective coating comprises, by weight, 80-90 parts of bisphenol A type epoxy resin, 40-50 parts of solvent, 10-15 parts of organic silicon resin, 6-9 parts of PVDF resin, 11-15 parts of inorganic filler, 6-10 parts of zinc powder, 5-10 parts of zirconium isopropoxide, 4-7 parts of styrene-acrylonitrile-glycidyl methacrylate copolymer, 2-4 parts of silane coupling agent, 7-11 parts of graphene and 2-4 parts of hydroxypropyl methyl cellulose, the inorganic filler is at least one of zinc oxide, titanium dioxide and silicon dioxide, and the B component comprises a curing agent.
  2. 2. The neodymium-iron-boron magnet according to claim 1, wherein the silane coupling agent is at least one of gamma-aminopropyl triethoxysilane, gamma- (methacryloyloxy) propyl trimethoxysilane, vinyl trimethoxysilane and vinyl triethoxysilane.
  3. 3. The oxidation resistant neodymium-iron-boron magnet according to claim 1, wherein the neodymium-iron-boron substrate comprises, by mass, 20.8-23.2% of neodymium, 6.9-7.5% of praseodymium, 0.9-1.15% of boron, 3.2-3.8% of dysprosium, 1.5-1.9% of cerium, 2.1-2.4% of lanthanum, 0.5-0.7% of cobalt, 0.3-0.5% of zirconium, 0.15-0.18% of copper, 2.2-4.1% of graphene and the balance of iron.
  4. 4. The method for preparing the antioxidant neodymium-iron-boron magnet according to any one of claims 1 to 3, comprising the following steps: (1) Mixing neodymium, praseodymium, boron, dysprosium, cerium, lanthanum, cobalt, zirconium and copper in proportion, smelting to obtain an alloy ingot, preparing the alloy ingot into a rapid hardening sheet by adopting a rapid hardening method, and carrying out hydrogen crushing treatment on the rapid hardening sheet to obtain hydrogen broken fragments; (2) Uniformly mixing the magnet alloy powder and the graphene powder to prepare neodymium iron boron magnetic powder, then orienting the neodymium iron boron magnetic powder in a magnetic field under the protection of inert gas, and performing compression molding to prepare a magnet green body; (3) Carrying out isostatic pressing treatment on the magnet green body, then placing the magnet green body into a sintering furnace for sintering, and then carrying out tempering treatment to obtain a neodymium iron boron matrix; (4) And (3) immersing the neodymium-iron-boron matrix in protective coating, and then drying to obtain the antioxidant neodymium-iron-boron magnet.
  5. 5. The method of claim 4, wherein in the step (1), the rapid hardening method comprises the steps of crushing the melted alloy ingot, heating the alloy ingot by a high-frequency induction coil to melt the alloy ingot, charging argon gas, spraying the melted alloy on a water-cooled copper roller for rapid hardening, wherein the linear speed of the copper roller is 25-35m/s, and cooling the alloy to form a rapid hardening sheet.
  6. 6. The method of claim 4, wherein in the step (1), the hydrogen pressure of the hydrogen crushing treatment is 0.06-0.09MPa, the treatment temperature is 360-380 ℃, the hydrogen absorption time is 2.5-3.5h, and then the dehydrogenation is performed at 400-420 ℃.
  7. 7. The method of claim 4, wherein in the step (2), the NdFeB magnetic powder is oriented in a magnetic field having a magnetic field strength of 1.8 to 2.4T.
  8. 8. The method of claim 4, wherein in the step (3), the green body is subjected to isostatic pressing at a pressure of 230-280MPa for 100-150s, and then sintered in a vacuum sintering furnace, and tempered to obtain the NdFeB magnet.
  9. 9. The method of claim 4, wherein in the step (4), the neodymium-iron-boron substrate is immersed in the protective coating for 40-70s, the neodymium-iron-boron substrate is taken out, spin-dried at a rotation speed of 200-300r/min, and then the coating is cured at a temperature of 60-70 ℃ for 10-30min to obtain the anti-oxidation neodymium-iron-boron magnet coated with the protective coating.

Description

Antioxidant neodymium-iron-boron magnet and preparation method thereof Technical Field The invention relates to the technical field of magnets, in particular to an antioxidant neodymium iron boron magnet and a preparation method thereof. Background The main components of the neodymium-iron-boron magnet are neodymium, iron, boron, rare earth elements and the like, and the neodymium-iron-boron permanent magnet can be divided into sintered neodymium-iron-boron and bonded neodymium-iron-boron according to different production processes. With the development of economy and the progress of science and technology, the performance of the neodymium-iron-boron magnet is continuously improved. The sintered NdFeB adopts a powder metallurgy technology, the smelted alloy is made into powder and pressed into a pressing block in a magnetic field, and then the pressing block is sintered in inert gas or vacuum to achieve densification, so that the NdFeB magnet has been widely applied to fields of electronics, electric machinery, medical equipment, toys, packaging, hardware machinery, aerospace and the like due to excellent magnetic performance and higher cost benefits, and has good application prospect and market potential. However, in the prior art, due to the fact that the gaps on the surface of the neodymium-iron-boron magnet are more, the problems of easy oxidation and rust, poor corrosion resistance and the like often exist, the performance of the neodymium-iron-boron magnet is reduced, and the application method of the neodymium-iron-boron magnet is limited, so that the neodymium-iron-boron magnet with excellent oxidation resistance, corrosion resistance and magnetic performance is developed, the application range of the neodymium-iron-boron magnet is widened, the market competitiveness is improved, the development of the magnet industry is promoted, and the application method has important significance. Disclosure of Invention In order to overcome the defects and shortcomings in the prior art, the invention aims to provide an antioxidant NdFeB magnet and a preparation method thereof, the invention is characterized in that the outer surface of a NdFeB matrix is coated with a protective coating, the anti-oxidation NdFeB magnet is prepared, the protective coating is tightly combined with the NdFeB matrix, so that the oxidation resistance and corrosion resistance of the NdFeB magnet are improved, and the service life of the NdFeB magnet is prolonged. The preparation method of the antioxidant neodymium iron boron magnet is convenient to operate and control, high in production efficiency, stable in product quality and beneficial to large-scale production. The invention discloses an anti-oxidation neodymium-iron-boron magnet which comprises a neodymium-iron-boron substrate and a protective coating coated on the outer surface of the neodymium-iron-boron substrate, wherein the protective coating is prepared from the following raw materials, by weight, 80-90 parts of bisphenol A type epoxy resin, 40-50 parts of a solvent, 10-15 parts of organic silicon resin, 6-9 parts of PVDF resin, 11-15 parts of inorganic filler, 6-10 parts of zinc powder, 5-10 parts of zirconium isopropoxide, 4-7 parts of a styrene-acrylonitrile-glycidyl methacrylate copolymer, 2-4 parts of a silane coupling agent, 7-11 parts of graphene and 2-4 parts of hydroxypropyl methyl cellulose. According to the invention, the anti-oxidation neodymium-iron-boron magnet is prepared by coating the outer surface of the neodymium-iron-boron substrate with the protective coating, the protective coating is prepared by compounding bisphenol A type epoxy resin with raw materials such as organic silicon resin, PVDF resin, zirconium isopropoxide, styrene-acrylonitrile-glycidyl methacrylate copolymer and the like, the prepared protective coating is tightly combined with the neodymium-iron-boron substrate, the anti-oxidation and corrosion resistance of the neodymium-iron-boron magnet are improved, and the neodymium-iron-boron magnet has good magnetic property and mechanical property and excellent comprehensive performance. Further, the inorganic filler is at least one of zinc oxide, titanium dioxide and silicon dioxide. Further, the inorganic filler is composed of zinc oxide, titanium dioxide and silicon dioxide according to a weight ratio of 2-4:1-2:1-2. The particle size of the inorganic filler is 10-30nm. The particle size of the zinc powder is 50-100nm. Further, the silane coupling agent is at least one of gamma-aminopropyl triethoxysilane, gamma- (methacryloyloxy) propyl trimethoxysilane, vinyl trimethoxysilane and vinyl triethoxysilane. Further, the component B comprises the following raw materials, by weight, 2-6 parts of a curing agent and 4-8 parts of a diluent. Further, the curing agent is at least one of ethylenediamine, hexamethylenediamine and diethylenetriamine. Further, the neodymium iron boron matrix comprises, by mass, 20.8-23.2% of neodymium, 6.9-7.5% of praseo