CN105225780A - A kind of high temperature resistant anisotropic bond samarium iron nitrogen magnet and preparation method thereof - Google Patents

Abstract

A high-temperature-resistant anisotropic samarium-iron-nitrogen bonded magnet and a preparation method thereof belong to the technical field of functional materials. The present invention uses anisotropic samarium-iron-nitrogen magnetic powder as the magnetic substance, uses sodium silicate as the main binder, and uses high-temperature-resistant epoxy resin as the auxiliary binder to obtain an anisotropic bonded samarium-iron-nitrogen magnet that not only has relatively high With high magnetic properties, its temperature resistance has also been greatly improved, and the working environment temperature can reach 200 ° C, and it has the advantages of anti-permeation and corrosion resistance. A high-temperature-resistant anisotropic bonded samarium-iron-nitrogen magnet and its preparation method according to the present invention, the obtained magnet has high magnetic properties and high service temperature, and the equipment is simple, easy to operate and low in cost during the implementation process. It is easy to produce on a large scale, has high economic value, and has great application prospects in the field of permanent magnet materials.

Description

A high temperature resistant anisotropic bonded samarium iron nitrogen magnet and its preparation method

technical field

The patent discloses a high-temperature-resistant anisotropic bonded samarium-iron-nitrogen magnet and a preparation method thereof, belonging to the technical field of functional materials.

Background technique

In 1990, HongSun and Coey synthesized the interstitial intermetallic compound R ₂ Fe ₁₇ N _x by gas-solid reaction, which aroused widespread concern in the magnetic field and immediately became a hot spot in the field of magnetic research at home and abroad. The national "Twelfth Five-Year Plan" 863 major project undertaken by the Applied Magnetics Center of Peking University has successfully developed a samarium-iron-nitrogen anisotropic magnetic powder production line and realized the product supply market.

In recent years, the rapid development of wind power generation, electric vehicles and maglev train motors has put forward higher requirements for the temperature of magnets. The Curie temperature of SmFeN magnetic powder is 470°C, which is higher than that of NdFeB magnetic powder (312°C). Therefore, SmFeN permanent magnet materials are facing new development opportunities due to their good high temperature resistance. Compared with the existing rare earth magnetic powder, the anisotropic SmFeN magnetic powder has high magnetic energy product, good high temperature resistance and low material cost. The bonded SmFeN magnet prepared by using anisotropic SmFeN magnetic powder not only inherits the high magnetic energy product of the magnetic powder, but also can reduce the required magnet volume to meet the development needs of the current miniaturization of electrical appliances. Therefore, the research and development of high temperature resistant bonded SmFeN magnets has good practical significance and application prospects.

The binders initially used for SmFeN permanent magnets include rubber, nylon, epoxy resin, phenolic resin, PS, PPS, polyimide-epoxy composite resin, etc., but due to the shortcomings of the binder itself, the obtained The mechanical properties and thermal stability of the magnets need to be improved (Ye Jinwen, Liu Ying, Zhang Ran, Chen Mei, Zhu Guoli, Gao Shengji, Tu Mingjing. Preparation of isotropic SmFeN magnetic powder and its bonded magnet[J ]. Rare Metal Materials and Engineering, 2007,36(2):329-331.). In recent years, studies have found that low-melting point metals such as Zn, Al, Pb, Sn, and Pb-Sn alloys can be used as binders, and the magnets made can be applied to higher temperatures, but the remanence of the magnets drops seriously (Wang Min , Li Hongwei, Yu Dunbo, Li Kuoshe, Luo Yang. Influencing factors of magnetic properties of SmFeN bonded permanent magnets [J]. Metal Functional Materials, 2010,17(2):72-76.). The high-temperature resistant anisotropic bonded samarium-iron-nitrogen magnet of the present invention uses sodium silicate as the main binder and high-temperature-resistant epoxy resin as the auxiliary binder, which not only can maintain the magnetic properties of the samarium-iron-nitrogen magnetic powder to the greatest extent, It can also effectively improve the temperature resistance of the magnet, and its working environment temperature can reach 200°C.

Sodium silicate is used as the bonded magnet binder. Japanese patents have reported a method for preparing bonded magnet parts by mixing sodium silicate and magnetic powder and then molding them. The bonded magnet parts can be used in motors, generators, etc. It works normally in a slightly high temperature environment, but there is a problem of large moisture absorption in the magnet parts, and necessary surface treatment is required before use (MinamiTadashi, NakamuraKatsuya, OdakaneMasaaki.Manufactureofbondmagnet.Japan, H01F41/02, 1997.). If sodium silicate and high-temperature epoxy resin are used for bonded magnets at the same time, the resulting magnets will combine the advantages of epoxy bonded magnets and sodium silicate bonded magnets, and have the advantages of high temperature resistance, strengthening and toughening, anti-permeation and moisture absorption. , corrosion resistance and other aspects have unique advantages. Sodium silicate has good heat resistance and strength, which can make up for the lack of high temperature resistance of epoxy resin and improve the strength performance of magnets; at the same time, epoxy resin penetrates into the sodium silicate system on a molecular scale, and forms silicon after cross-linking and curing. The interpenetrating network structure of sodium bicarbonate and epoxy resin will improve the anti-permeation performance and corrosion resistance of the magnet, and further reduce its hygroscopicity.

The present invention uses anisotropic samarium-iron-nitrogen magnetic powder as the magnetic substance, uses sodium silicate as the main binder, and uses high-temperature-resistant epoxy resin as the auxiliary binder, and the anisotropic bonded samarium-iron-nitrogen magnet prepared not only has With high magnetic properties, its temperature resistance has also been greatly improved, and the working environment temperature can reach 200 ° C, and it has the advantages of anti-permeation and corrosion resistance.

Contents of the invention

The object of the present invention is to provide a high-temperature resistant anisotropic bonded samarium-iron-nitrogen magnet and its preparation method, the raw materials are easy to obtain, large-scale production is possible and the cost is low.

A high-temperature-resistant anisotropic bonded SmFeN magnet of the present invention is a bonded magnet made by using anisotropic SmFeN magnetic powder and binder as main raw materials, and then adding an appropriate amount of surfactant and lubricant . The mass ratios of the main components of the magnet are: anisotropic samarium-iron-nitrogen magnetic powder 90-96%, sodium silicate binder 3-6.5%, epoxy binder 0.5-3.3%, surfactant 0.1- 0.3%, lubricant 0.1-0.3%.

The sodium silicate binder is an aqueous sodium silicate solution with a modulus of 3.1-3.4 and a Baume degree of 39-41°.

The surfactant is preferably selected from: KH-550, KH-560, KH-570, stearic acid, aluminate, titanate.

Described lubricant is preferably selected from: paraffin, glycerol, silicate, silicone oil.

The preparation method of a high temperature resistant anisotropic bonded samarium iron nitrogen magnet of the present invention is as follows:

The first step is to mix anisotropic samarium iron nitrogen magnetic powder with a certain quality of surfactant, and stir evenly to obtain bonded magnetic powder A;

In the second step, the bonded magnetic powder A obtained in the first step is mixed with the epoxy binder according to a certain mass ratio, and stirred evenly until the magnetic powder is loose, and the bonded magnetic powder B is obtained;

The third step is to mix the bonded magnetic powder B obtained in the second step with the sodium silicate binder according to the mass ratio, and stir evenly until the magnetic powder is loose to obtain the bonded magnetic powder C;

The fourth step is to mix the bonded magnetic powder C obtained in the third step with a certain quality of lubricant, and stir evenly to obtain the bonded magnetic powder D;

The fifth step is to spray a little organic solvent into the bonded magnetic powder D obtained in the fourth step to accelerate the volatilization of water in the binder, and stir until the magnetic powder becomes loose to obtain the bonded magnetic powder E;

The sixth step is to place the appropriate amount of bonded magnetic powder E obtained in the fifth step into a mold and vibrate it, firstly orientate it in a magnetic field in an orientation molding machine, and then press molding, and demoulding to obtain an initial magnet blank F;

In the seventh step, the initial magnet blank F obtained in the sixth step is placed in an isostatic pressing device to make it densified to obtain a densified magnet blank G;

In the eighth step, the densified magnet blank G obtained in the seventh step is placed in a vacuum or an inert gas environment for curing to obtain a high-temperature-resistant anisotropic bonded SmFeN magnet. The curing temperature is 175-200 °C and the time is 30-40 minutes. .

The epoxy adhesive is diluted and dissolved with a small amount of acetone before use, and can be used immediately after dissolving.

The organic solvent is one or more of acetone, methanol, ethanol and ethyl acetate.

Conventional anisotropic bonded SmFeN magnets mostly use epoxy resin as a binder, which is easy to mass produce and has precise dimensions. It is a common molding method for magnetic materials, but it has the disadvantage of low long-term use temperature, generally not exceeding 110 ℃, which limits the use of bonded magnets in some fields. Therefore, the development of anisotropic bonded SmFeN magnets with high temperature resistance not only has important application prospects in the field of permanent magnet materials, but also has very large economic value.

Compared with the prior art, the present invention has the following beneficial effects.

A high-temperature-resistant anisotropic bonded samarium-iron-nitrogen magnet of the present invention and its preparation method not only have high magnetic properties and a relatively high service temperature (200°C), but also have simple equipment and The method has the advantages of simple operation, low cost, easy large-scale production and high economic value. Therefore, the invention has great application prospects in the field of permanent magnet materials.

detailed description

The present invention will be further described below in conjunction with the examples, but the present invention is not limited to the following examples.

Embodiment 1: A method for preparing a high-temperature-resistant anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnet is carried out according to the following steps.

In the first step, mix 96g of anisotropic Sm ₂ Fe ₁₇ N ₃ magnetic powder with 0.3g of KH-550 and stir evenly to obtain bonded magnetic powder A1;

In the second step, mix the bonded magnetic powder A1 obtained in the first step with 0.5 g of epoxy binder, and stir evenly until the magnetic powder is loose to obtain the bonded magnetic powder B1;

In the third step, mix the bonded magnetic powder B1 obtained in the second step with 3 g of sodium silicate binder (modulus 3.1, Baume degree 40°), and stir evenly until the magnetic powder is loose to obtain bonded magnetic powder C1;

The fourth step is to mix the bonded magnetic powder C1 obtained in the third step with 0.2 g of paraffin, and stir evenly to obtain the bonded magnetic powder D1;

In the fifth step, spray 5ml of acetone into the bonded magnetic powder D1 obtained in the fourth step, and stir until the magnetic powder becomes loose to obtain the bonded magnetic powder E1;

The sixth step is to put the appropriate amount of bonded magnetic powder E1 obtained in the fifth step into the mold and vibrate it, first use a 10T magnetic field in the orientation molding machine to orientate, then press and form, and demould to obtain the initial magnet blank F1;

In the seventh step, the initial magnet blank F1 obtained in the sixth step is placed in an isostatic pressing device to make it densified to obtain a densified magnet blank G1;

In the eighth step, the densified magnet blank G1 obtained in the seventh step is placed in a vacuum environment for curing to obtain a high-temperature-resistant anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnet. The curing temperature is 175° C. for 40 minutes.

Using the same process steps in this implementation example, replace the sodium silicate binder with an epoxy binder of the same quality to obtain an anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnet 1"#. The obtained Table 1 shows the temperature coefficient data of two anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 1# and 1"#. The magnetic properties at room temperature and 200°C of the anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 1# and 1"# obtained in this embodiment are shown in Table 2.

Table 1 Temperature coefficient of magnetic properties (easy axis) of anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 1# and 1”#

Note: Bonded magnet 1”# only uses epoxy resin as the adhesive, and its working environment does not exceed 110°C.

Table 2 Magnetic properties (easy axis) of anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 1# and 1”#

Note: The bonded magnet 1"# only uses epoxy resin as the adhesive, and it crumbles when tested at 200°C, and there is no data.

Embodiment 2: A method for preparing a high-temperature-resistant anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnet is carried out according to the following steps.

In the first step, mix 93g of anisotropic Sm ₂ Fe ₁₇ N ₃ magnetic powder with 0.2g of KH-560 and stir evenly to obtain bonded magnetic powder A2;

In the second step, mix the bonded magnetic powder A2 obtained in the first step with 1.5 g of epoxy binder, and stir evenly until the magnetic powder is loose to obtain the bonded magnetic powder B2;

In the third step, mix the bonded magnetic powder B2 obtained in the second step with 5 g of sodium silicate binder (modulus 3.2, Baume degree 39°), and stir evenly until the magnetic powder is loose to obtain bonded magnetic powder C2;

The fourth step is to mix the bonded magnetic powder C2 obtained in the third step with 0.3 g of silicone oil, and stir evenly to obtain the bonded magnetic powder D2;

In the fifth step, spray 4ml of ethanol into the bonded magnetic powder D2 obtained in the fourth step, and stir until the magnetic powder becomes loose to obtain the bonded magnetic powder E2;

The sixth step is to put the appropriate amount of bonded magnetic powder E2 obtained in the fifth step into a mold and vibrate it, first use a 10T magnetic field in the orientation molding machine to orientate, then press and form, and demould to obtain the initial magnet blank F2;

The seventh step is to place the initial magnet blank F2 obtained in the sixth step in an isostatic pressing device to densify it to obtain a densified magnet blank G2;

In the eighth step, the densified magnet blank G2 obtained in the seventh step is placed in an argon atmosphere for curing to obtain a high-temperature-resistant anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnet. The curing temperature is 188° C. for 35 minutes.

Using the same process steps in this implementation example, replace the sodium silicate binder with an epoxy binder of the same quality to obtain an anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnet 2"#. The obtained in this implementation example The temperature coefficient data of two anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 2# and 2”# are shown in Table 3. The magnetic properties at room temperature and 200°C of the anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 2# and 2"# obtained in this embodiment are shown in Table 4.

Table 3 Temperature coefficient of magnetic properties (easy axis) of anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 2# and 2”#

Note: Bonded magnet 2”# only uses epoxy resin as the adhesive, and its working environment does not exceed 110°C.

Table 4 Magnetic properties of anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 2# and 2”# (easy axis)

Note: The bonded magnet 1"# only uses epoxy resin as the adhesive, and it crumbles when tested at 200°C, and there is no data.

Embodiment 3: A method for preparing a high-temperature resistant anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnet is carried out according to the following steps.

In the first step, mix 90g of anisotropic Sm ₂ Fe ₁₇ N ₃ magnetic powder with 0.1g of KH-570 and stir evenly to obtain bonded magnetic powder A3;

In the second step, mix the bonded magnetic powder A3 obtained in the first step with 3.3 g of epoxy binder, and stir evenly until the magnetic powder is loose to obtain the bonded magnetic powder B3;

In the third step, mix the bonded magnetic powder B3 obtained in the second step with 6.5 g of sodium silicate binder (modulus 3.4, Baume degree 41°), and stir evenly until the magnetic powder is loose, and obtain bonded magnetic powder C3 ;

The fourth step is to mix the bonded magnetic powder C3 obtained in the third step with 0.1 g of paraffin, and stir evenly to obtain the bonded magnetic powder D3;

In the fifth step, spray 5ml of acetone into the bonded magnetic powder D3 obtained in the fourth step, and stir until the magnetic powder becomes loose to obtain the bonded magnetic powder E3;

The sixth step is to put the appropriate amount of bonded magnetic powder E3 obtained in the fifth step into a mold and vibrate it, first use a 10T magnetic field in the orientation molding machine to orientate, then press and form, and demould to obtain the initial magnet blank F3;

In the seventh step, the initial magnet blank F3 obtained in the sixth step is placed in an isostatic pressing device to densify it to obtain a densified magnet blank G3;

In the eighth step, the densified magnet blank G3 obtained in the seventh step is placed in a vacuum environment for curing to obtain a high-temperature-resistant anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnet. The curing temperature is 200° C. for 30 minutes.

Using the same process steps in this implementation example, replace the sodium silicate binder with an epoxy binder of the same quality to obtain an anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnet 3 "#. The obtained in this implementation example Table 5 shows the temperature coefficient data of two anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 3# and 3”#. The magnetic properties at room temperature and 200°C of the anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 3# and 3"# obtained in this embodiment are shown in Table 6.

Table 5 Temperature coefficient of magnetic properties (easy axis) of anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 3# and 3”#

Note: Bonded magnet 3”# only uses epoxy resin as the adhesive, and its working environment does not exceed 110°C.

Table 6 Magnetic properties of anisotropic bonded Sm ₂ Fe ₁₇ N ₃ magnets 3# and 3”# (easy axis)

Note: The bonded magnet 1"# only uses epoxy resin as the adhesive, and it crumbles when tested at 200°C, and there is no data.

Claims (7)

1. A high-temperature-resistant anisotropic bonded SmFeN magnet is characterized in that it is made of anisotropic SmFeN magnetic powder and binder as the main raw materials, and then added an appropriate amount of surfactant and lubricant bonded magnets. The mass ratios of the main components of the magnet are: anisotropic samarium-iron-nitrogen magnetic powder 90-96%, sodium silicate binder 3-6.5%, epoxy binder 0.5-3.3%, surfactant 0.1- 0.3%, lubricant 0.1-0.3%. 2. A high-temperature-resistant anisotropic bonded samarium-iron-nitrogen magnet according to claim 1, characterized in that the sodium silicate binder is an aqueous solution of sodium silicate, with a modulus of 3.1 to 3.4 and a Baume degree of 39 ~41°. 3. A high temperature resistant anisotropic bonded samarium iron nitrogen magnet according to claim 1, characterized in that the surfactant is preferably selected from: KH-550, KH-560, KH-570, stearic acid , aluminate, titanate. 4. A high temperature resistant anisotropic bonded samarium iron nitrogen magnet according to claim 1, characterized in that the lubricant is preferably selected from: paraffin wax, glycerin, silicate, silicone oil. 5. The method for preparing the high temperature resistant anisotropic bonded samarium iron nitrogen magnet of claim 1, is characterized in that, comprises the following steps: The first step is to mix anisotropic samarium iron nitrogen magnetic powder with a certain quality of surfactant, and stir evenly to obtain bonded magnetic powder A; In the second step, the bonded magnetic powder A obtained in the first step is mixed with the epoxy binder according to a certain mass ratio, and stirred evenly until the magnetic powder is loose, and the bonded magnetic powder B is obtained; The third step is to mix the bonded magnetic powder B obtained in the second step with the sodium silicate binder according to the mass ratio, and stir evenly until the magnetic powder is loose to obtain the bonded magnetic powder C; The fourth step is to mix the bonded magnetic powder C obtained in the third step with a certain quality of lubricant, and stir evenly to obtain the bonded magnetic powder D; The fifth step is to spray a little organic solvent into the bonded magnetic powder D obtained in the fourth step to accelerate the volatilization of water in the binder, and stir until the magnetic powder becomes loose to obtain the bonded magnetic powder E; The sixth step is to place the appropriate amount of bonded magnetic powder E obtained in the fifth step into a mold and vibrate it, firstly orientate it in a magnetic field in an orientation molding machine, and then press molding, and demoulding to obtain an initial magnet blank F; In the seventh step, the initial magnet blank F obtained in the sixth step is placed in an isostatic pressing device to make it densified to obtain a densified magnet blank G; In the eighth step, the densified magnet blank G obtained in the seventh step is placed in a vacuum or an inert gas environment for curing to obtain a high-temperature-resistant anisotropic bonded SmFeN magnet. The curing temperature is 175-200 °C and the time is 30-40 minutes. . 6. according to the method for claim 5, it is characterized in that, described epoxy binding agent is diluted with acetone and dissolved earlier before use, instant use. 7. according to the method for claim 5, it is characterized in that, described organic solvent is the mixing of one or more in acetone, methyl alcohol, ethanol, ethyl acetate.