WO2017210957A1 - 一种稀土永磁材料的制备方法 - Google Patents

一种稀土永磁材料的制备方法 Download PDF

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WO2017210957A1
WO2017210957A1 PCT/CN2016/089872 CN2016089872W WO2017210957A1 WO 2017210957 A1 WO2017210957 A1 WO 2017210957A1 CN 2016089872 W CN2016089872 W CN 2016089872W WO 2017210957 A1 WO2017210957 A1 WO 2017210957A1
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rare earth
magnetic
ndfeb
magnet
alloy powder
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PCT/CN2016/089872
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French (fr)
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郝忠彬
韩相华
章晓峰
洪群峰
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浙江东阳东磁稀土有限公司
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/14—Both compacting and sintering simultaneously
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0576—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together pressed, e.g. hot working
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/06—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/08—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/14—Both compacting and sintering simultaneously
    • B22F2003/145—Both compacting and sintering simultaneously by warm compacting, below debindering temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B22F2003/248—Thermal after-treatment

Definitions

  • the present invention relates to the technical field of magnetic materials, and in particular to a method for preparing a rare earth permanent magnet material.
  • NdFeB permanent magnet materials are the most excellent permanent magnetic materials with comprehensive magnetic properties. They are known as "Magnetic King” and are of great significance for miniaturization, integration and high efficiency of devices.
  • the NdFeB magnets are mainly divided into sintered, bonded, hot-pressed/thermally deformed magnets, in which the amount of sintered NdFeB is the largest.
  • the preparation process of the sintered NdFeB magnet is mainly obtained by a rapid setting process to obtain a NdFeB alloy, and then the alloy is ground to obtain a powder of 3-5 ⁇ , and the powder is placed in a magnetic field to form a green body, and the green body is
  • the sintered NdFeB blank is obtained by sintering at a temperature of 1040-1100 ° C, and the blank is mechanically processed to finally obtain a sintered NdFeB product.
  • the main advantage of sintered magnets is their high magnetic properties.
  • the maximum magnetic energy product of general commercial magnets is generally 200-400 kJm - 3 , and the NEOMAX laboratory level in Japan is up to 474 kJm - 3 , which is the highest record of magnetic materials to date.
  • the main disadvantage of sintered NdFeB is the low material utilization. This is because, in addition to a small number of large-size products that can be produced by monolithic molding, most other sintered NdFeB products require machining, and the overall material utilization rate is about 66%, while for some sheets and shaped products, materials The utilization rate is less than 50%.
  • the sintering shrinkage rate of the sintered NdFeB magnet is about 30%, and the density of the green body is not uniform, so the deformation cracking of the sintered NdFeB is unavoidable, so the sintered NdFeB magnet improves the space utilization ratio. Still very big.
  • the hot-pressing/heat-deformed NdFeB magnet is prepared by compacting a nanocrystalline quenched NdFeB magnetic powder having a particle size of about 200 ⁇ at 500-600 °C to obtain an isotropic magnet, and then passing 850-950. An anisotropic NdFeB magnet is obtained by thermal deformation at °C.
  • the coercive force of the hot-pressed/thermally deformed magnet is slightly higher than that of the sintered NdFeB, because the temperature used for hot pressing/thermal deformation is lower than the sintering temperature, and the time is short, so the crystal grains are finer. .
  • the hot-pressed/hot-deformed magnet can be formed into a net size or a nearly net-size molding, and at the same time, the deformation and cracking of the magnet can be effectively suppressed, so that the material utilization rate is high.
  • the main disadvantage of hot pressed/thermally deformed magnets is their high cost.
  • the nanocrystalline quick-quenching magnetic powder used for hot pressing has a higher price; at the same time, the thermal deformation process has a low production efficiency, so the production cost is high.
  • Bonded NdFeB magnets are also prepared by using nanocrystalline quenched magnetic powder to bond magnetic powder into a magnet by adding a certain proportion of adhesive.
  • the material utilization rate of the bonded NdFeB magnet is very high, close to 100%, and the preparation of the shaped product can be realized.
  • the biggest disadvantage of bonding NdFeB is that the magnetic properties are low, and the magnetic energy product of the bonded NdFeB magnets is mostly 60-90 kJm- 3 .
  • the advantages of sintered NdFeB magnets are that the magnetic powder is cheap, the production process is simple, the efficiency is high, and the cost is low; the disadvantage is that the sintering temperature is high (above 1040 ° C), the crystal grains of the magnet are easy to grow, and the material utilization rate is low. Easy to deform and crack.
  • the advantage of the hot-pressed/thermally deformed magnet is that the magnet crystal is fine and the material utilization rate is high; the disadvantage is that the magnetic powder (hot pressing/heat deformation special quick quenching powder) has high price, low heat deformation efficiency and high cost.
  • the advantage of the bonded NdFeB magnet is that the material utilization rate is high, and the production of the shaped magnet can be realized; the main disadvantage is that the magnetic property is low, and the magnetic energy product of the bonded NdFeB magnet is mostly 60-90 kJnr 3 .
  • the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a method for preparing a rare earth permanent magnet material having high magnetic properties and low production cost.
  • a method for preparing a rare earth permanent magnet material includes the following steps:
  • the NdFeB alloy is prepared by a vacuum melting furnace, and then coarsely crushed by a hydrogen explosion method or a mechanical crushing method, and then ground by a jet milling process to obtain a NdFeB alloy powder;
  • Secondary molding The primary molded product is placed in a secondary molded mold, and the molded product is heated under vacuum or inert gas, and then pressure is applied for secondary molding to obtain a densified magnet. ;
  • the second-molded magnet is placed in a vacuum furnace for heat treatment, and at least includes a homogenization heat treatment for passivating the sharp corners of the grains and a tempering heat treatment for optimizing the grain boundary phase distribution.
  • the NdFeB alloy powder is used to prepare a neodymium iron boron magnet by two successive molding processes; an orientation magnetic field is applied during one molding to obtain an anisotropic NdFeB green body, which is passed during the secondary molding.
  • the NdFeB alloy powder used is a microcrystalline or single crystal particle, and the average particle size range of the NdFeB alloy powder obtained by the grinding is controlled to be 1-10 ⁇ .
  • the NdFeB powder used is a microcrystalline or single crystal particle, so that it can be prepared by an ordinary vacuum melting furnace, and the cost of the magnetic powder is low.
  • the rare earth-rich alloy powder is added, and the composition of the rare earth-rich alloy powder is: one of rare earth elements lanthanum, cerium, lanthanum, cerium or a plurality of other non-rare earth elements are one or more of aluminum, copper, gallium, and iron, and the sum of the mass percentages of the rare earth elements lanthanum, cerium, lanthanum, and cerium is more than 50%; the proportion of the rare earth-rich alloy powder is 0-30% of NdFeB alloy powder. This can reduce the temperature of the secondary molding, help to suppress grain growth and extend the life of the mold, while improving production efficiency.
  • the rare earth-rich alloy powder has an average particle size range of 0.3 to 4 ⁇ m. It is made similar to the average particle diameter of the NdFeB alloy powder to suppress grain growth.
  • the overmolded mold is designed according to the shape and size of the final desired product to be prepared, and in the step (2), the one-time molded mold is designed according to the second-molded mold. .
  • This design allows the product to be close to the size of the final product and the material utilization rate is high when the molding process is employed.
  • the primary molded product is heated to 550 to 1000 ° C, the hot pressing time is 1 to 30 minutes, and then a pressure of 1 to 500 MPa is applied for secondary molding. Since the heating temperature of the secondary molding is much lower than the sintering temperature, the magnet crystal grains are finer than the conventional sintered magnets, and the magnetic properties are high.
  • the homogenization heat treatment process for passivating the sharp corners of the crystal grains is as follows: the heat treatment is performed at 700-1000 ° C for 1-15 hours; the tempering heat treatment process for optimizing the grain boundary phase distribution is as follows: Incubate at 650 ° C for 1-6 hours.
  • the magnetic properties reach 200 kJnr 3 or more, which is much higher than the bonded NdFeB magnet, which is also a key process for the process to produce a commercially valuable magnet.
  • the stress relief treatment process is further increased: the temperature is maintained at 150-350 ° C for 0.5-3 hours. This helps to improve the magnetic properties and bending strength of the magnet.
  • the beneficial effects of the invention are:
  • the densification temperature is low, the grain growth can be inhibited, the crystal grains are smaller than the sintered magnet, and the magnetic properties are high. It can be found from the microstructure observation that the crystal size of the magnet obtained by the invention is small, 1-5 ⁇ ⁇ . , similar to the average particle size of the NdFeB alloy powder, no significant grain growth occurred during the secondary molding densification process;
  • the magnet size is close to the size of the final product, and the material utilization rate is much higher than that of the conventional sintered NdFeB magnet;
  • the magnetic performance is high, and the maximum magnetic energy product reaches 200 kJnr 3 or more, which is much higher than the bonded NdFeB magnet.
  • the NdFeB alloy is prepared by vacuum melting furnace, and the alloy with the main alloy composition of Nd26.25Pr8.75Fe64Bl (mass percentage) is made into a thin film by using the quick-condensing sheet technology; then the hydrogen explosion method and the air jet grinding process are used to speed up.
  • the condensed sheet is made into a powder having an average particle diameter of 3.5 ⁇ m;
  • Example 1 Using the magnet of Example 1, adding 5% Nd70Cu30 (mass percent) of rare earth-rich alloy powder to the NdFeB alloy powder obtained after Step 1, wherein the average particle size of the beryllium copper alloy powder is 3 ⁇ ;
  • step 3 the hot pressing temperature is 680 ° C, and the other processes are the same as in the first embodiment.
  • Example 2 The magnet of Example 2 was subjected to a heat treatment after the step 4, and subjected to a stress relief tempering treatment at 340 ° C for X 2.5 hours.
  • Example 2 The same batch of magnetic powder orientation molding as in Example 1 was carried out, and the green size was 43.56X39.6X29.82, which was sintered and densified at 1068 ° C according to the conventional sintering process, and heat-treated in the same manner as in Example 1.
  • Example 1 The preparation process and product characteristics of Example 1, Example 2, Example 3 and Comparative Example 1 are shown in Table 1.
  • the average grain size of the magnetized and compacted magnets in Example 2 and Example 3 was about 3.6 ⁇ m, which was close to the particle size of the magnetic powder; the average grain size of the magnet in Example 1 was 3.8 ⁇ m, which was in the process of high temperature molding densification. The grain growth is very small.
  • the average grain size of the magnet of Comparative Example 1 was about 5.5 ⁇ m, which indicates that the technique has a significant effect on grain refinement. It shows that the preparation process using the invention can be obviously The magnet grain size is reduced, and the grain boundary phase distribution is more uniform. Since the shape of the magnet product prepared by using the invention can meet some customer requirements without processing, the material utilization rate is close.
  • NdFeB magnets prepared by different processes are shown in Table 2.
  • the magnetic properties of NdFeB magnets produced by the secondary molding process, especially Hqj, are low, failing to meet the requirements of commercial magnets, and must be properly heat treated; the heat treatment process of secondary molded magnets and the heat treatment process of traditional NdFeB magnets There is a significant difference.
  • a homogenization heat treatment is required to passivate the sharp corners of the grains, and then a tempering heat treatment for optimizing the grain boundary structure is performed.
  • the magnetic properties of the magnet after the above heat treatment have been significantly improved, which is similar to that of the sintered NdFeB magnet, and some indexes are superior to the sintered NdFeB magnet, which is much higher than the bonded NdFeB magnet.
  • the densification temperature of the magnet can be lowered, thereby further refining the crystal grains, and the magnet Hcj is also somewhat improved.
  • the stress relief treatment can further improve the magnetic properties of the magnet, especially the magnet side.
  • the shape (Hk/Hcj) is advantageous for increasing the maximum magnetic energy product of the magnet and reducing the irreversible magnetic flux loss of the magnet.
  • Example 1 From the comparison of Example 1, Example 2, Example 3 and Comparative Example 1 in Tables 1 and 2 above, it is understood that the present invention can produce rare earth grains with small crystal grains and low cost by hot-pressing sintered NdFeB green body. Magnetic material.

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Abstract

提供一种稀土永磁材料的制备方法，采用钕铁硼合金粉末，通过连续两次模压工艺制备钕铁硼磁体；在一次模压时需施加取向磁场，得到各向异性的钕铁硼生坯，在二次模压时通过加热加压，得到致密的钕铁硼磁体，而且磁体的尺寸接近最终产品的尺寸；并通过特殊的热处理工艺来提高磁体磁性能。其有益效果是：致密化温度低，可抑制晶粒长大，晶粒较烧结磁体细小，磁性能高；采用模压工艺，磁体尺寸接近最终成品的尺寸，材料利用率远高于传统烧结钕铁硼磁体；不需要专用快淬磁粉，不需要热变形，工艺简单，生产效率高，生产成本远低于热压/热变形磁体；磁性能高，最大磁能积达到200kJm ‑3以上，远高于粘结钕铁硼磁体。

Description

一种稀土永磁材料的制备方法
技术领域
本发明涉及磁性材料相关技术领域， 尤其是指一种稀土永磁材料的制备 方法。
背景技术
自上世纪 80年代钕铁硼磁体问世以来， 由于其优异的磁性能迅速在电 子、 通讯、 交通运输、 自动化、 医疗和新能源等领域获得广泛的应用。 到目 前为止， 钕铁硼永磁材料是综合磁性能最优异的永磁材料， 被誉为 "磁王"， 对器件小型化、 集成化和高效率具有重要意义。
按制备方法分， 钕铁硼磁体主要分为烧结、 粘结、 热压 /热变形磁体， 其 中以烧结钕铁硼用量最大。 烧结钕铁硼磁体的制备工艺主要是采用速凝工艺 得到钕铁硼合金， 然后将合金磨碎得到 3-5 μ πι的粉末，将粉末放入磁场中取 向成型得到生坯， 将生坯在 1040-1100°C温度烧结得到烧结钕铁硼毛坯， 毛坯 再经过机械加工最终得到烧结钕铁硼产品。烧结磁体的主要优点是磁性能高， 一般商用磁体的最大磁能积一般在 200-400 kJm-3 , 日本 NEOMAX公司实验 室水平最高达到 474 kJm-3， 这也是迄今为止磁性材料的最高纪录。 而烧结钕 铁硼的主要缺点是材料利用率低。 这是因为除了少部分大规格产品可以通过 单片成型制得以外， 其他大部分烧结钕铁硼产品都需要机械加工， 综合材料 利用率约为 66%， 而对于一些薄片和异形产品来说材料利用率不到 50%。 另 外， 烧结钕铁硼磁体的烧结收缩率约为 30%， 加之生坯的密度不均匀， 所以 烧结钕铁硼的变形开裂是不可避免的， 所以说烧结钕铁硼磁体提高材料利用 率的空间还很大。 热压 /热变形钕铁硼磁体的制备工艺是将粒度约为 200 μ πΐ的纳米晶快淬 钕铁硼磁粉在 500-600 °C热压致密得到各向同性磁体， 然后再经过 850-950°C 下热变形得到各向异性钕铁硼磁体。 一般来说， 热压 /热变形磁体的内禀矫顽 力要比烧结钕铁硼的略高， 这是因为热压 /热变形采用的温度比烧结温度低， 时间短， 所以晶粒更细小。 而且热压 /热变形磁体可以实现净尺寸或接近净尺 寸成型， 同时也可以有效地抑制磁体的变形开裂， 所以材料利用率较高。 热 压 /热变形磁体的主要缺点是成本高。 首先热压所用的纳米晶快淬磁粉价格较 高； 同时热变形工艺生产效率很低， 所以生产成本高。
粘结钕铁硼磁体也是采用纳米晶快淬磁粉制备的， 通过添加一定比例的 粘接剂将磁粉粘结成的磁体。粘结钕铁硼磁体的材料利用率很高，接近 100%， 而且可以实现异形产品的制备。 粘结钕铁硼的最大缺点是磁性能低， 粘结钕 铁硼磁体磁能积大都在 60-90kJm-3。
综上所述， 烧结钕铁硼磁体的优点是磁粉便宜， 生产工艺简单， 效率高， 成本低； 缺点是烧结温度高（1040°C以上）， 磁体晶粒容易长大， 材料利用率 低， 易变形开裂。 热压 /热变形磁体的优点是磁体晶粒细小， 材料利用率高； 缺点是磁粉 （热压 /热变形专用快淬粉） 价格高， 热变形效率低， 成本高。 粘 结钕铁硼磁体的优点是材料利用率高， 可以实现异形磁体的生产； 主要缺点 是磁性能低， 粘结钕铁硼磁体磁能积大都在 60-90kJnr3。
发明内容
本发明是为了克服现有技术中存在上述的不足，提供了一种磁性能高且生 产成本低的稀土永磁材料的制备方法。
为了实现上述目的， 本发明采用以下技术方案： 一种稀土永磁材料的制备方法， 包括如下步骤：
( 1 ) 磁粉准备： 采用真空熔炼炉制备钕铁硼合金， 之后采用氢爆法或机 械破碎法进行粗破碎， 再采用气流磨工艺进行研磨制得钕铁硼合金 粉末；
(2 ) 一次模压： 将粉末放入一次模压的模具中模压成型， 同时对磁粉施 加大于 1T的磁场；
(3 ) 二次模压： 将一次模压的产品置入二次模压的模具内， 在真空或惰 性气体保护下， 将一次模压的产品加热后， 然后施加压力进行二次 模压， 得到致密化的磁体；
(4 ) 热处理： 将经过二次模压的磁体置入真空炉内进行热处理， 至少包 括钝化晶粒尖角的均匀化热处理和优化晶界相分布的回火热处理。 本发明中， 采用的钕铁硼合金粉末， 通过连续两次模压工艺制备钕铁硼 磁体； 在一次模压时需施加取向磁场， 得到各向异性的钕铁硼生坯， 在二次 模压时通过加热加压， 得到致密的钕铁硼磁体， 而且磁体的尺寸接近最终产 品的尺寸； 由于二次模压后得到的磁体磁性能很低， 所以需要通过特殊的热 处理工艺来提高磁体磁性能。 采用模压工艺， 产品接近最终成品的尺寸， 材 料利用率高； 无需热变形， 生产效率高， 所以成本远低于热压 /热变形磁体； 磁性能达到 200 kJm-3以上， 远高于粘结钕铁硼磁体。
作为优选， 在步骤（1 ) 中， 所采用的钕铁硼合金粉末为微米晶或单晶颗 粒， 研磨制得的钕铁硼合金粉末平均粒径范围控制在 1-10 μ πι。 所采用的钕 铁硼粉末为微米晶、 单晶颗粒， 故而采用普通真空熔炼炉制备即可， 磁粉成 本低。 作为优选， 在步骤（1 ) 中， 在研磨制得钕铁硼合金粉末之后， 加入富稀 土合金粉末， 富稀土合金粉末的组成成分为： 稀土元素镨、 钕、 镝、 铽中的 一种或多种， 其他非稀土元素是铝、 铜、 镓、 铁中的一种或多种， 且稀土元 素镨、 钕、 镝、 铽的质量百分比之和大于 50%; 富稀土合金粉末的添加比例 为钕铁硼合金粉末的 0-30%。 这样可以降低二次模压的温度， 有助于抑制晶 粒长大并延长模具使用寿命， 同时提高生产效率。
作为优选， 所述的富稀土合金粉末平均粒径范围控制在 0.3-4 μ πι。 使其 与钕铁硼合金粉末的平均粒径相近， 抑制晶粒长大。
作为优选， 在步骤（3 ) 中， 二次模压的模具是根据最终所需制备产品的 形状尺寸而设计的， 在步骤（2) 中， 一次模压的模具是根据二次模压的模具 而设计的。 这样设计使得在采用模压工艺时， 产品接近最终成品的尺寸， 材 料利用率高。
作为优选， 在步骤（3 ) 中， 将一次模压的产品加热到 550-1000°C， 热压 时间为 1-30分钟， 然后施加 l-500MPa的压力进行二次模压。 由于二次模压 的加热温度远低于烧结温度， 所以磁体晶粒比传统烧结磁体细小， 磁性能高。
作为优选， 在步骤（4) 中， 钝化晶粒尖角的均匀化热处理工艺如下： 采 用 700-1000°C保温 1-15小时； 优化晶界相分布的回火热处理工艺如下： 采用 400-650°C保温 1-6小时。 通过上述特殊的热处理工艺来提高磁体磁性能， 使 得磁性能达到 200 kJnr3以上， 远高于粘结钕铁硼磁体， 这也是该工艺能制得 有商用价值磁体的关键工序。
作为优选， 在步骤 （4) 之后， 再增加去应力处理工艺： 采用 150-350°C 保温 0.5-3小时。 这样有助于提高磁体的磁性能和抗弯强度。 本发明的有益效果是：
1、 致密化温度低， 可抑制晶粒长大， 晶粒较烧结磁体细小， 磁性能高； 通过显微结构观察可以发现， 本发明制得的磁体晶粒尺寸细小， 为 1-5 μ πΐ， 与钕铁硼合金粉末的平均粒径相近， 在二次模压致密化过程中没有发生明显 晶粒长大的现象；
2、 采用模压工艺， 磁体尺寸接近最终成品的尺寸， 材料利用率远高于传 统烧结钕铁硼磁体；
3、 不需要专用快淬磁粉， 不需要热变形， 工艺简单， 生产效率高， 生产 成本远低于热压 /热变形磁体；
4、 磁性能高， 最大磁能积达到 200 kJnr3以上， 远高于粘结钕铁硼磁体。 具体实施方式
下面结合具体实施方式对本发明做进一步的描述。
实施例 1 :
1、采用真空熔炼炉制备钕铁硼合金， 利用速凝薄片技术将主合金成分为 Nd26.25Pr8.75Fe64Bl (质量百分含量） 的合金制成薄片； 然后利用氢爆法和 气流磨工艺将速凝薄片制成平均粒径为 3.5 μ m 的粉末；
2、 施加 1.5T 的磁场， 一次模压得到毛坯尺寸 R8.1 X R3.6 X 10， 毛坯重 量 29.97g;
3、将一次模压得到的毛坯置于二次模压的模具内， 二次模压的模具处于 一个密闭的空间， 先抽空至 8 X 10-3Pa， 再充氩气到 8 X 104Pa， 然后升温至 780°C， 沿厚度 10的方向加压 200MPa， 保压 6分钟后冷却取出； 4、将经过二次模压的磁体置入真空炉内进行二次热处理，分别采用 900 °C 保温 8小时以及 500°C保温 4小时工艺对热压毛坯进行热处理， 制得规格为 R8.1XR3.6X5.3的磁体， 材料利用率 100%， 无掉角开裂， 成品率 100%。
实施例 2:
1、采用实施例 1中的磁体， 在步骤 1之后制得的钕铁硼合金粉末中添加 5%Nd70Cu30 (质量百分含量） 富稀土合金粉末， 其中钕铜合金粉末的平均 粒径为 3 μπΐ;
2、 在步骤 3中， 热压温度为 680°C， 其他工艺与实施例 1相同。
实施例 3:
将实施例 2的磁体在经过步骤 4的热处理后， 进行 340°C X2.5小时的去 应力回火处理。
比较例 1:
采用与实施例 1同批磁粉取向成型， 生坯规格 43.56X39.6X29.82， 按传 统烧结工艺在 1068°C烧结致密化， 与实施例 1相同工艺热处理。
烧结毛坯规格 33X30X2， 线切害 IJ成 R8.1XR3.6X5.5的黑片并进行内外 弧磨加工， 最终得到 R8.1XR3.6X5.3的磁体， 材料利用率 76%， 机械加工费 用 0.3元 /只， 加工过程中有掉角， 成品率 98%。
实施例 1、 实施例 2、 实施例 3与比较例 1的制备工艺及产品特性对比见 表 1。 实施例 2和实施例 3中模压致密化后磁体的平均晶粒尺寸大约为 3.6 μ m， 与磁粉的粒度接近； 实施例 1中磁体平均晶粒尺寸为 3.8 μπι， 在高温模 压致密化过程中晶粒长大非常小。比较例 1磁体的平均晶粒尺寸约为 5.5 μπι， 这说明该技术对晶粒细化有明显效果。 表明采用本发明的制备工艺可以明显 的减小磁体晶粒尺寸， 而且晶界相分布更均匀。 由于使用该发明制备的磁体 产品外形尺寸无需加工即可满足部分客户使用要求， 所以材料利用率接近
100%， 对于公差要求较高的产品需要进行简单加工。 采用该技术制备的产品 在机械加工性能方面优于传统工艺， 所以成品率有所提升， 甚至可以达到
100%。
表 1
Figure imgf000009_0001
采用不同工艺制备的钕铁硼磁体各项磁性能指标见表 2。 采用二次模压 工艺制得的钕铁硼磁体磁性能， 特别是 Hqj很低， 达不到商用磁体的要求， 必须进行适当的热处理； 二次模压磁体的热处理工艺与传统钕铁硼磁体热处 理工艺有明显不同， 首先需要进行均匀化热处理用以钝化晶粒尖角， 然后进 行优化晶界结构的回火热处理。 通过上述热处理后磁体的磁性能有了明显提 升， 与烧结钕铁硼磁体相近， 甚至有部分指标优于烧结钕铁硼磁体， 远高于 粘结钕铁硼。
在实施例 2中， 通过添加富稀土合金粉末， 可以降低磁体致密化温度， 从而进一步细化晶粒， 磁体 Hcj也有一定提高。
在实施例 3中， 去应力处理可以进一步改善磁体磁性能， 特别是磁体方 形度（Hk/Hcj )，有利于提高磁体的最大磁能积和减小磁体的不可逆磁通损失。
表 2
Figure imgf000010_0001
从上述表 1和表 2中实施例 1、 实施例 2、 实施例 3和对比例 1的比较可 知， 本发明通过热压烧结钕铁硼生坯能够制得晶粒细小、 成本低廉的稀土永 磁材料。

Claims

WO 2017/210957 权 利 要 求 书 PCT/CN2016/089872
1. 一种稀土永磁材料的制备方法， 其特征是， 包括如下步骤：
( 1 ) 磁粉准备：采用真空熔炼炉制备钕铁硼合金，之后采用氢爆法或机械破 碎法进行粗破碎， 再采用气流磨工艺进行研磨制得钕铁硼合金粉末；
(2 ) 一次模压：将粉末放入一次模压的模具中模压成型， 同时对磁粉施加大 于 1T的磁场；
( 3 ) 二次模压：将一次模压的产品置入二次模压的模具内，在真空或惰性气 体保护下， 将一次模压的产品加热后， 然后施加压力进行二次模压， 得 到致密化的磁体；
(4 ) 热处理：将经过二次模压的磁体置入真空炉内进行热处理，至少包括钝 化晶粒尖角的均匀化热处理和优化晶界相分布的回火热处理。
2. 根据权利要求 1所述的一种稀土永磁材料的制备方法，其特征是，在步骤（1 ) 中， 所采用的钕铁硼合金粉末为微米晶或单晶颗粒， 研磨制得的钕铁硼合金 粉末平均粒径范围控制在 1-10 μ πι。
3. 根据权利要求 1或 2所述的一种稀土永磁材料的制备方法， 其特征是， 在步 骤（1 ) 中， 在研磨制得钕铁硼合金粉末之后， 加入富稀土合金粉末， 富稀土 合金粉末的组成成分为： 稀土元素镨、 钕、 镝、 铽中的一种或多种， 其他非 稀土元素是铝、 铜、 镓、 铁中的一种或多种， 且稀土元素镨、 钕、 镝、 铽的 质量百分比之和大于 50%; 富稀土合金粉末的添加比例为钕铁硼合金粉末的 0-30%。
4. 根据权利要求 3所述的一种稀土永磁材料的制备方法， 其特征是， 所述的富 稀土合金粉末平均粒径范围控制在 0.3-4 μ m。
5. 根据权利要求 1所述的一种稀土永磁材料的制备方法，其特征是，在步骤（3 ) WO 2017/210957 权 利 要 求 书 PCT/CN2016/089872 中， 二次模压的模具是根据最终所需制备产品的形状尺寸而设计的， 在步骤
(2 ) 中， 一次模压的模具是根据二次模压的模具而设计的。
6. 根据权利要求 1所述的一种稀土永磁材料的制备方法，其特征是，在步骤（3 ) 中， 将一次模压的产品加热到 550-1000°C， 热压时间为 1-30分钟， 然后施加 l-500MPa的压力进行二次模压。
7. 根据权利要求 1所述的一种稀土永磁材料的制备方法，其特征是，在步骤（4 ) 中，钝化晶粒尖角的均匀化热处理工艺如下：采用 700-1000°C保温 1-15小时； 优化晶界相分布的回火热处理工艺如下： 采用 400-650Ό保温 1-6小时。
8. 根据权利要求 1所述的一种稀土永磁材料的制备方法，其特征是，在步骤（4 ) 之后， 再增加去应力处理工艺： 采用 150-350°C保温 0.5-3小时。
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Cited By (1)

* Cited by examiner, † Cited by third party
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1696324A (zh) * 2005-05-18 2005-11-16 西北有色金属研究院 一种高使用温度的耐热钕铁硼合金材料及其制备方法
CN103594243A (zh) * 2013-11-20 2014-02-19 宁波科田磁业有限公司 防止烧结钕铁硼磁体开裂的制造方法
CN104851544A (zh) * 2015-05-21 2015-08-19 唐海峰 一种低能耗钕铁硼磁性材料的制备方法
JP2015225880A (ja) * 2014-05-26 2015-12-14 大同特殊鋼株式会社 焼結磁石製造方法
CN105225782A (zh) * 2015-07-31 2016-01-06 浙江东阳东磁稀土有限公司 一种无重稀土的烧结钕铁硼磁体及其制备方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103123843B (zh) * 2011-11-21 2015-10-07 中国科学院宁波材料技术与工程研究所 一种细晶粒各向异性致密化钕铁硼永磁体的制备方法
JP5870914B2 (ja) * 2012-12-25 2016-03-01 トヨタ自動車株式会社 希土類磁石の製造方法
CN103680918B (zh) * 2013-12-11 2016-08-17 烟台正海磁性材料股份有限公司 一种制备高矫顽力磁体的方法
CN104269238B (zh) * 2014-09-30 2017-02-22 宁波科田磁业有限公司 一种高性能烧结钕铁硼磁体和制备方法
CN105118649A (zh) * 2015-06-18 2015-12-02 浙江东阳东磁稀土有限公司 一种改善钕铁硼磁体晶界相的方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1696324A (zh) * 2005-05-18 2005-11-16 西北有色金属研究院 一种高使用温度的耐热钕铁硼合金材料及其制备方法
CN103594243A (zh) * 2013-11-20 2014-02-19 宁波科田磁业有限公司 防止烧结钕铁硼磁体开裂的制造方法
JP2015225880A (ja) * 2014-05-26 2015-12-14 大同特殊鋼株式会社 焼結磁石製造方法
CN104851544A (zh) * 2015-05-21 2015-08-19 唐海峰 一种低能耗钕铁硼磁性材料的制备方法
CN105225782A (zh) * 2015-07-31 2016-01-06 浙江东阳东磁稀土有限公司 一种无重稀土的烧结钕铁硼磁体及其制备方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108417378A (zh) * 2018-03-30 2018-08-17 严高林 一种含镝的钕铁硼磁体及其制备方法

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