WO2016111346A1 - RFeB系焼結磁石の製造方法 - Google Patents
RFeB系焼結磁石の製造方法 Download PDFInfo
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- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
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- 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
- B22F3/10—Sintering only
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- 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
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- 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
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- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
- B22F2009/044—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by jet milling
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- B—PERFORMING OPERATIONS; TRANSPORTING
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Definitions
- the present invention relates to a method for producing an RFeB-based sintered magnet mainly containing rare earth elements (R) containing Y, iron (Fe), and boron (B).
- the RFeB-based sintered magnet is a permanent magnet manufactured by orienting and sintering RFeB-based alloy powder.
- RFeB magnets were discovered by Sagawa et al. In 1982 and have high magnetic properties far surpassing conventional permanent magnets, and are manufactured from relatively abundant and inexpensive raw materials such as rare earths, iron and boron. It has the feature that it can be.
- RFeB sintered magnets are expected to increase in the future, such as permanent magnets for motors for automobiles used in hybrid vehicles, electric vehicles, fuel cell vehicles, etc. Since the motor for automobiles rises from room temperature to about 180 ° C. during use, the RFeB-based sintered magnet used for automobile motors must be guaranteed to operate in this temperature range. For this purpose, there is a demand for an RFeB-based sintered magnet having a high coercive force over the entire temperature range.
- the coercive force is an index indicating the strength of a magnetic field in which the magnetization becomes zero when a magnetic field opposite to the magnetization direction is applied to the magnet.
- the larger the coercive force value the more resistant to the reverse magnetic field. high.
- the coercive force generally has a temperature characteristic that it decreases as the temperature rises, and the higher the coercive force at normal temperature (room temperature), the higher the coercive force at high temperature. For this reason, conventionally, contrivances have been made to increase the value using the coercive force at normal temperature as an index.
- coercive force it means a coercive force at room temperature.
- Non-patent document 1 One way to improve the coercivity of NdFeB sintered magnets without using RH is to reduce the grain size of the main phase (R 2 Fe 14 B) inside the NdFeB sintered magnet. It is well known that the coercive force of any ferromagnetic material (or ferrimagnetic material) is increased by reducing the grain size of the internal crystal grains.
- HDR processing is known.
- HDDR treatment is performed by heating R 2 Fe 14 B raw material alloy lump or coarse powder (hereinafter collectively referred to as “raw material alloy lump”) in a hydrogen atmosphere at 700 to 1000 ° C. (Hydrogenation).
- Decomposition of R 2 Fe 14 B compound into three phases of RH 2 , Fe 2 B, and Fe (decomposition), while maintaining the temperature, switch the atmosphere from hydrogen to vacuum to release hydrogen from the RH 2 phase ( This causes a recombination reaction to the R 2 Fe 14 B compound.
- crystal grains which are phases of the R 2 Fe 14 B compound having an average diameter of 1 ⁇ m or less and a narrow particle size distribution are formed inside the raw material alloy lump.
- Patent Document 1 discloses a sintered magnet made of powder obtained by pulverizing a raw material alloy lump after the HDDR treatment (hereinafter referred to as a “post-HDDR raw material alloy lump”) with a jet mill using nitrogen gas. Manufacturing is described. However, since the jet mill using nitrogen gas cannot be sufficiently pulverized as described above, the particle diameter of the raw material alloy powder obtained by pulverizing the material alloy lump after HDDR is larger than the conventional one. Despite being small, the particle size of the particle itself is only as large as the conventional one. Thus, in the method of Patent Document 1, since the raw material alloy powder particles include a plurality of crystal grains, even if a magnetic field is applied to the raw material alloy powder particles in the orientation step, the individual crystal grains are oriented. The residual magnetic flux density is reduced.
- the present inventor uses a helium gas instead of nitrogen gas to process the alloy lump with a jet mill (helium jet mill method), so that the raw material alloy lump has an average particle size of 1 ⁇ m or less (submicron size).
- a jet mill helium jet mill method
- this pulverization method was applied to the raw alloy mass after HDDR (Patent Document 2).
- the raw material alloy powder thus obtained has a high content of particles consisting of only one crystal grain. Therefore, by orienting this raw material alloy powder in a magnetic field, individual crystal grains can be easily oriented, and the residual magnetic flux density can be increased. And, as described above, the coercive force can be increased by reducing the crystal grain size.
- Patent Document 3 describes that Nd and Bd alloy masses after HDDR processing are crushed so that the average particle size is about 100 ⁇ m, Nd and Mixing fine powder of alloy containing Cu, applying a magnetic field to this mixture, then heating to 700 ° C with a hot press machine and heating at 2 ton / cm 2 pressure to produce a compact of NdFeB magnet It is described to do.
- an envelope layer made of Nd and Cu is formed around the Nd 2 Fe 14 B type crystal grains, and magnetic interaction between adjacent crystal grains is blocked by the envelope layer, thereby improving the coercive force.
- this method is not a sintering method and uses a magnet raw material having a particle size about two orders of magnitude larger than that of the sintering method, the residual magnetic flux density cannot be increased.
- the method of Patent Document 2 is excellent in that both the coercive force and the residual magnetic flux density can be improved.
- the present inventor has found that the width of a two-grain boundary, which is a grain boundary sandwiched between two adjacent crystal grains. It was found that the distance between crystal grains (hereinafter referred to as “grain boundary width”) is narrower than that of a conventional RFeB-based sintered magnet. If the grain boundary width of the two grain boundaries is narrow, a magnetic interaction called exchange coupling occurs between adjacent crystal grains, and a magnetic domain in which magnetization is reversed is easily formed.
- the present inventor further considered the reason why the grain boundary width of some of the two grain boundaries is narrowed by the method described in Patent Document 2.
- a rare earth-rich phase having a higher content of rare earth R than R 2 Fe 14 B between the particles of the raw material alloy powder in the stage immediately before sintering. It is desirable to exist as uniformly as possible. The reason will be explained.
- the rare earth-rich phase Since the rare earth-rich phase has a lower melting point than R 2 Fe 14 B, the rare earth-rich phase is melted by heating for sintering and penetrates between the particles of the raw material alloy powder. As described above, in the method described in Patent Document 2, since the particles of the raw material alloy powder are composed of only one crystal grain at a high rate, if a state in which the rare earth-rich phase exists uniformly between the particles can be realized, In an RFeB-based sintered magnet obtained by sintering such raw material alloy powder, a rare earth-rich phase extends over the two grain boundaries of the crystal grains, and the grain boundary width of the two grain boundaries becomes wide.
- the raw material alloy lump before the HDDR treatment is typically produced by a strip casting method.
- a thin plate-like rare earth-rich phase is formed at intervals of 3 to 5 ⁇ m (lamellar). Called the structure), the rare earth-rich phase does not sufficiently penetrate all of the RFeB-based crystal grains formed between the rare earth-rich phases forming the lamellar structure, and the uneven distribution of the rare earth-rich phase It can be seen. It is difficult to uniformly disperse the rare earth-rich phase even by a method other than the strip casting method.
- the distribution of the rare earth-rich phase becomes non-uniform.
- the rare earth-rich phase does not reach the grain boundaries uniformly, so a two-grain grain boundary with a wide grain boundary width is not formed, and the coercive force decreases. Resulting in.
- the problem to be solved by the present invention is that the average grain size of the crystal grains is 1 ⁇ m or less and the rare earth-rich phase is evenly distributed over the grain boundaries, so that the two-grain grain boundaries having a wide grain boundary width are uniform. It is to provide a method of manufacturing an RFeB-based sintered magnet having a high coercive force by being formed.
- the present invention made to solve the above problems is a method for producing an RFeB-based sintered magnet mainly composed of rare earth elements R, Fe and B, a) An HDDR that heats an RFeB alloy ingot with a rare earth element R content of 26.5 to 29.5% by weight in a hydrogen atmosphere at a temperature of 700 to 1000 ° C and then maintains the temperature at 750 to 900 ° C to create a vacuum
- a process for producing a raw material alloy post-HDDR composed of a polycrystalline body of crystal grains having an average grain diameter of 1 ⁇ m or less with an equivalent circle diameter determined from an electron microscope image; b) Heating to a temperature of 700 to 950 ° C.
- a process of producing a high-content raw material alloy lump (rare earth grain boundary infiltration process); c) producing a raw material alloy powder by pulverizing the rare earth-rich raw material alloy ingot so that the average particle size is 1 ⁇ m or less; d) storing the raw material alloy powder in a mold and applying a magnetic field to the raw material alloy powder without performing compression molding; and e) a sintering step of heating the raw material alloy powder after the orientation step to a temperature of 850 to 1050 ° C.
- an HDDR-treated raw material alloy lump made of a polycrystal of fine crystal grains having an average value of the particle size distribution due to the equivalent circle diameter of 1 ⁇ m or less is produced by the HDDR treatment, and then contains R more than the RFeB-based alloy.
- a contact made of a second alloy having a high rate is heated to a temperature of 700 to 950 ° C. in a contact state.
- the second alloy melts and uniformly penetrates into the grain boundaries in the raw material alloy block after the HDDR treatment.
- individual crystal grains are in contact with the second alloy.
- the second alloy is present on the surface of each particle composed of only one crystal grain at a high rate as described above.
- the second alloy (rare earth-rich phase) melts and reaches the two-grain grain boundary, so that the composition and grain of the two-grain grain boundary
- An RFeB-based sintered magnet with a uniform field width can be obtained.
- the RFeB-based sintered magnet manufactured according to the present invention has a high coercive force due to a two-grain grain boundary having a small average grain size of 1 ⁇ m or less and a wide grain boundary width.
- the content of the rare earth element R in the raw RFeB alloy ingot is lower than 26.5% by weight, the rare earth element R in the crystal grains of the manufactured RFeB sintered magnet will be insufficient. Further, if the content of the rare earth element R in the RFeB-based alloy ingot is higher than 29.5% by weight, the residual magnetic flux density of the RFeB-based sintered magnet is lowered. Therefore, in the present invention, the content of the rare earth element R in the RFeB-based alloy ingot is 26.5 to 29.5% by weight.
- the second alloy is not particularly limited as long as it melts at the heating temperature in the rare earth grain boundary infiltration treatment step, and the components other than the rare earth element R are not particularly limited.
- the raw material RFeB alloy ingot should be made by a strip cast method that can increase the uniformity of the rare earth-rich phase dispersion compared to other methods (although there is a problem due to the lamellar structure described above). Is desirable.
- the average grain size of the crystal grains is 1 ⁇ m or less, and the rare earth-rich phase is uniformly distributed at the grain boundaries, so that a two-grain grain boundary having a wide grain boundary width is formed uniformly.
- an RFeB-based sintered magnet having a high coercive force can be produced.
- the figure (a) which shows the flow of the process in the Example of the manufacturing method of the RFeB type sintered magnet concerning this invention, and the figure (b) which shows the flow of the process of a comparative example.
- the graph which shows the temperature history and gas atmosphere at the time of the HDRD process in a present Example.
- Reflected electron image of the rare earth-rich raw material alloy lump (a) produced in the course of the manufacturing method of the RFeB-based sintered magnet of Example 2 and the pre-HDDR raw material alloy lump (b), which was the previous stage, observed with an electron microscope .
- the backscattered electron images of the post-HDDR raw material alloy ingot produced in the process of manufacturing the RFeB sintered magnet of the comparative example were observed with an electron microscope.
- (A) is a comparative example 1
- (b) is a comparative example. Two things.
- Example 1 [Method for producing RFeB-based sintered magnet of Example 1]
- the HDRR process (Step S1), rare earth particles
- An RFeB-based sintered magnet was manufactured by five processes: a field penetration treatment process (step S2), a raw material alloy powder production process (step S3), an orientation process (step S4), and a sintering process (step S5).
- “TRE” in Table 1 indicates the total content of all rare earth elements (Nd and Pr in Example 1) contained in the RFeB alloy ingot.
- the HDDR process will be described with reference to the graph of FIG.
- an RFeB alloy ingot with an equivalent circle diameter of 100 ⁇ m to 20 mm prepared by a strip casting method is prepared.
- the RFeB alloy ingot is fully occluded with hydrogen at room temperature and then heated in a hydrogen atmosphere at 950 ° C and 100 kPa for 60 minutes to convert the Nd 2 Fe 14 B compound (main phase) in the raw alloy alloy after HDDR to NdH Decomposition into two phases, Fe 2 B phase and Fe phase (“HD process” in FIG. 2).
- the temperature was lowered to 800 ° C.
- the resulting alloy material after HDDR was coarsely pulverized with a Wonder Blender (Osaka Chemical Co., Ltd.) to an equivalent circle diameter of 100 ⁇ m or less. It is included in the raw material alloy block after HDDR in the invention.
- the coarsely pulverized raw material alloy after HDDR and the second alloy powder previously pulverized to a mean particle size of 4 ⁇ m by a jet mill using nitrogen gas were mixed at a weight ratio of 95: 5, and 700
- a rare earth-rich raw material alloy ingot was produced by heating at a temperature of 10 ° C. for 10 minutes.
- the rare earth-rich raw material alloy lump is embrittled by maintaining it in a hydrogen atmosphere at a temperature of 200 ° C. for 5 hours, and then the average particle size is reduced to 1 ⁇ m or less by the helium jet mill method.
- the raw material alloy powder was produced by pulverizing.
- an organic lubricant was mixed with the raw material alloy powder, and the mold was filled at a filling density of 3.5 g / cm 3 , and a pulse magnetic field of about 5 T was applied without performing compression molding.
- the raw material alloy powder filled in the mold was sintered by heating at a temperature of 940 ° C. for 1 hour in vacuum without performing compression molding.
- heat treatment was performed in an argon atmosphere for 10 minutes at a temperature between 500 ° C. and 660 ° C. with the highest coercive force.
- a cylindrical RFeB sintered magnet having a diameter of 9.8 mm and a length of 7.0 mm was produced.
- Example 2 [Method for producing RFeB-based sintered magnet of Example 2]
- an RFeB-based alloy ingot having the composition shown in Table 2 below and the powder of the second alloy were used as materials, and an RFeB-based sintered magnet was basically produced by the same method as in Example 1. .
- Example 1 the differences from Example 1 other than the composition of the materials are listed.
- the powder of the 2nd alloy was produced using the wonder blender instead of the jet mill using nitrogen gas. Therefore, the average particle diameter of the second alloy powder is larger than that of the first embodiment.
- the mixing ratio of the raw alloy alloy mass after HDDR and the powder of the second alloy was 94: 6 by weight, and the heating time was 30 minutes (heating temperature is 700 ° C. as in Example 1). . -The sintering temperature in the sintering process was 860 ° C.
- Example 3 [Methods for producing RFeB-based sintered magnets of Examples 3 to 7]
- the same composition (different from Examples 1 and 2) is used for the RFeB alloy ingot, and the powder of the second alloy has a different composition Was used.
- the composition of the powder of the second alloy of Example 3 is the same as that of Examples 1 and 2.
- the differences from Example 1 are as follows. In the rare earth grain boundary infiltration treatment process, the mixing ratio of the raw alloy alloy mass after HDDR and the powder of the second alloy was 95: 5 by weight, and the heating time was 60 minutes (heating temperature is 700 ° C. same as in Example 1). .
- the sintering temperature in the sintering process was 890 ° C. in Examples 3 and 4, and 880 ° C. in Examples 5-7.
- the raw alloy alloy mass after HDDR is maintained in a hydrogen atmosphere at a temperature of 200 ° C. for 5 hours in the raw alloy powder production step.
- a raw material alloy powder was produced by pulverizing so as to have an average particle diameter of 1 ⁇ m or less by a helium jet mill method.
- the raw material alloy powder thus obtained was subjected to the same orientation step and sintering step as in Examples 1 and 2, thereby obtaining a RFeB sintered magnet of a comparative example.
- Table 4 shows the results of measuring the composition at the stage of the raw material alloy powder (considered to be close to the composition of the obtained RFeB-based sintered magnet) in Examples 1 and 2 and Comparative Examples 1 and 2. Paying attention to the value of TRE, both the examples and comparative examples are higher than the TRE value of the main phase of 26 to 27% by weight (when the rare earth element R is Nd, Pr), and the raw material alloy powder as a whole is higher than the main phase. The content of the rare earth element R is high.
- the composition of the RFeB-based alloy ingot and the mixing ratio of the RFeB-based alloy ingot and the second alloy powder are the same as those in Examples 3 and 4, and the second alloy powder contains Ga. This is different from the third and fourth embodiments. Thus, it became clear that both high saturation magnetization and high coercive force can be obtained by containing Ga in the powder of the second alloy.
- FIG. 3 (a) shows a rare earth-rich raw material alloy ingot of Example 2
- FIG. 3 (b) shows a post-HDDR raw material alloy ingot of Example 2
- FIG. 4 (a) shows a post-HDDR raw material alloy ingot of Comparative Example 1
- FIG. 4 (b) shows an electron micrograph of the post-HDDR raw material alloy ingot of Comparative Example 2. Comparing the photographs of the alloy lumps just before the raw material alloy powder production process, that is, comparing FIG. 3 (a) and FIGS. 4 (a) and (b), the gray particles in FIG. In contrast, in FIGS. 4 (a) and 4 (b), which are comparative examples, white portions can be seen in the form of dots in a wide gray area.
- Example 2 the rare earth-rich phase composed of the second alloy spreads uniformly at the grain boundaries of the crystal grains (gray particles) in the rare earth-rich raw material alloy ingot, whereas in the comparative example, the rare earth This means that the rich phase is not distributed uniformly at the grain boundary but is localized at the point-like portion. Therefore, in the raw material alloy powder obtained by pulverizing the rare earth-rich raw material alloy lump of Example 2, the rare earth rich phase is uniformly distributed between the particles, and in the RFeB sintered magnet obtained by sintering the raw material alloy powder, the rare earth rich phase is crystallized.
- a two-grain grain boundary with a wide grain boundary width is formed because it is uniformly distributed between grains, whereas the rare earth-rich phase is uniform between grains in the raw alloy powder obtained by grinding the raw alloy mass after HDDR of the comparative example. Even in the RFeB sintered magnet obtained by sintering the raw material alloy powder, the rare earth-rich phase does not spread uniformly between the crystal grains, so that a two-grain grain boundary with a wide grain boundary width is not formed. Conceivable.
- Example 2 In the electron micrograph of the raw material alloy post-HDDR in Example 2 shown in FIG. 3 (b), a white portion is hardly seen. This is because the TRE value of the post-HDDR raw material alloy lump (and the pre-stage raw material alloy lump) in Example 2 is close to the TRE value in the main phase and has almost no rare earth-rich phase. As shown in FIG. 3 (a), the rare earth-rich phase is made of crystal grains as shown in FIG. A rare earth-rich raw material alloy ingot that reaches the boundary is obtained.
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Abstract
Description
a) 希土類元素Rの含有率が26.5~29.5重量%であるRFeB系合金塊を700~1000℃の温度の水素雰囲気中で加熱した後に、750~900℃の温度に維持しつつ真空にするHDDR処理を行うことにより、電子顕微鏡画像から求められた円相当径による平均粒径が1μm以下である結晶粒の多結晶体から成るHDDR後原料合金塊を作製する工程と、
b) 前記HDDR後原料合金塊に、前記RFeB系合金よりも希土類元素Rの含有率が高い第2合金から成る接触物を接触させた状態で700~950℃の温度に加熱することにより、希土類高含有原料合金塊を作製する工程(希土類粒界浸透処理工程)と、
c) 前記希土類高含有原料合金塊を、平均粒径が1μm以下になるように微粉砕することにより原料合金粉末を作製する工程と、
d) 前記原料合金粉末をモールドに収容し、圧縮成形を行うことなく該原料合金粉末に磁界を印加する配向工程と、
e) 該配向工程後の原料合金粉末を850~1050℃の温度に加熱する焼結工程と
を有することを特徴とする。
実施例1では、下掲の表1に示す組成を有するRFeB系合金塊及び第2合金の粉末を材料として用いて、図1(a)に示すように、HDDR工程(ステップS1)、希土類粒界浸透処理工程(ステップS2)、原料合金粉末作製工程(ステップS3)、配向工程(ステップS4)及び焼結工程(ステップS5)の5つの工程によりRFeB系焼結磁石を製造した。なお、表1中の「TRE」は、RFeB系合金塊が含有する全ての希土類元素(実施例1ではNd及びPr)を合わせた含有率を示している。
実施例2では、下掲の表2に示す組成を有するRFeB系合金塊及び第2合金の粉末を材料として用い、基本的には実施例1と同様の方法でRFeB系焼結磁石を作製した。以下では、材料の組成以外の実施例1との相違点を列挙する。
・第2合金の粉末は、窒素ガスを用いたジェットミルの代わりにワンダーブレンダーを用いて作製した。そのため、第2合金の粉末の平均粒径は第1実施例よりも大きい。
・希土類粒界浸透処理工程におけるHDDR後原料合金塊と第2合金の粉末の混合比は重量比で94:6とし、加熱時間は30分間とした(加熱温度は実施例1と同じ700℃)。
・焼結工程における焼結温度は860℃とした。
実施例3~7では、下掲の表3に示すように、RFeB系合金塊には同じ組成の(実施例1及び2とは異なる)ものを用い、第2合金の粉末では異なる組成のものを用いた。なお、実施例3の第2合金の粉末の組成は、実施例1及び2と同じである。材料の組成以外の条件につき、実施例1との相違点は以下の通りである。
・希土類粒界浸透処理工程におけるHDDR後原料合金塊と第2合金の粉末の混合比は重量比で95:5とし、加熱時間は60分間とした(加熱温度は実施例1と同じ700℃)。
・焼結工程における焼結温度は、実施例3及び4では890℃、実施例5~7では880℃とした。
比較例では、下掲の表3に示す組成を有する2種類のRFeB系合金塊を用いて、図1(b)に示すHDDR工程(ステップS91)、原料合金粉末作製工程(ステップS93)、配向工程(ステップS94)及び焼結工程(ステップS95)の4つの工程によりRFeB系焼結磁石を製造した。HDDR工程では、RFeB系合金塊に対して実施例1及び2と同じHDDR処理を行うことにより、HDDR後原料合金塊を作製した。次いで、実施例1及び2における希土類粒界浸透処理工程に相当する工程を行うことなく、原料合金粉末作製工程において、HDDR後原料合金塊を200℃の温度の水素雰囲気中で5時間維持することによって脆化させた後、ヘリウムジェットミル法により、平均粒径が1μm以下になるように粉砕することにより、原料合金粉末を作製した。こうして得られた原料合金粉末に対して、実施例1及び2と同様の配向工程及び焼結工程を行うことにより、比較例のRFeB系焼結磁石が得られた。
実施例1及び2、並びに比較例1及び2において、(得られたRFeB系焼結磁石の組成に近いと考えられる)原料合金粉末の段階における組成を測定した結果を表4に示す。TREの値に注目すると、実施例、比較例共に、主相のTRE値である26~27重量%(希土類元素RがNd, Prの場合)よりも高く、原料合金粉末全体では主相よりも希土類元素Rの含有率が高い状態となっている。
実施例及び比較例で得られたRFeB系焼結磁石の保磁力を測定したところ、下掲の表6の通りとなった。実施例3~7については、飽和磁化も測定した。この表に示すように、希土類粒界浸透処理工程の有無を除いてほぼ同じ条件で作製したにも関わらず、比較例よりも実施例の方が、保磁力が高くなった。また、実施例5~7は、実施例3及び4よりも飽和磁化が高く、保磁力は他の実施例と同程度に高い。これら実施例5~7は、RFeB系合金塊の組成やRFeB系合金塊と第2合金の粉末の混合比が実施例3及び4と同じであり、第2合金の粉末にGaが含まれている点で実施例3及び4と相違している。このように、第2合金の粉末にGaを含有させることにより、高い飽和磁化と高い保磁力の両方が得られることが明らかになった。
上記のように保磁力の相違が生じる理由を確かめるために、実施例2、並びに比較例1及び2における原料合金粉末作製工程の直前の合金塊の電子顕微鏡写真を撮影した。原料合金粉末作製工程の直前の合金塊は、実施例2では希土類高含有原料合金塊であり、比較例1及び2ではHDDR後原料合金塊である。実施例2に関しては、HDDR後原料合金塊についても電子顕微鏡写真を撮影した。
Claims (5)
- 希土類元素R、Fe及びBを主成分とするRFeB系焼結磁石の製造方法であって、
a) 希土類元素Rの含有率が26.5~29.5重量%であるRFeB系合金塊を700~1000℃の温度の水素雰囲気中で加熱した後に、750~900℃の温度に維持しつつ真空にするHDDR処理を行うことにより、電子顕微鏡画像から求められた円相当径による平均粒径が1μm以下である結晶粒の多結晶体から成るHDDR後原料合金塊を作製する工程と、
b) 前記HDDR後原料合金塊に、前記RFeB系合金よりも希土類元素Rの含有率が高い第2合金から成る接触物を接触させた状態で700~950℃の温度に加熱することにより、希土類高含有原料合金塊を作製する工程と、
c) 前記希土類高含有原料合金塊を、平均粒径が1μm以下になるように微粉砕することにより原料合金粉末を作製する工程と、
d) 前記原料合金粉末をモールドに収容し、圧縮成形を行うことなく該原料合金粉末に磁界を印加する配向工程と、
e) 該配向工程後の原料合金粉末を850~1050℃の温度に加熱する焼結工程と
を有することを特徴とするRFeB系焼結磁石製造方法。 - 前記RFeB系合金塊がストリップキャスト法により作製されたものであることを特徴とする請求項1に記載のRFeB系焼結磁石製造方法。
- 前記接触物が粉末状であることを特徴とする請求項1又は2に記載のRFeB系焼結磁石製造方法。
- 前記微粉砕を、ヘリウムガスを用いたジェットミル法により行うことを特徴とする請求項1~3のいずれかに記載のRFeB系焼結磁石製造方法。
- 前記第2合金がGaを含有することを特徴とする請求項1~4のいずれかに記載のRFeB系焼結磁石製造方法。
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EP16735085.9A EP3244426A1 (en) | 2015-01-09 | 2016-01-08 | PROCESS FOR PRODUCING RFeB-BASED SINTERED MAGNET |
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---|---|---|---|---|
JP2018152526A (ja) * | 2017-03-15 | 2018-09-27 | インターメタリックス株式会社 | RFeB系焼結磁石の製造方法 |
CN109148133A (zh) * | 2017-06-16 | 2019-01-04 | 中国科学院宁波材料技术与工程研究所 | 一种稀土永磁体及其制备方法 |
WO2023046005A1 (zh) * | 2021-09-22 | 2023-03-30 | 烟台正海磁性材料股份有限公司 | 一种高剩磁钕铁硼磁体及其制备方法和应用 |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
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JP7013992B2 (ja) | 2018-03-26 | 2022-02-01 | 東京電力ホールディングス株式会社 | 架線の撤去方法及び架線撤去用具 |
CN108922765B (zh) * | 2018-07-11 | 2021-02-09 | 江西开源自动化设备有限公司 | 一种稀土烧结永磁体的制造方法 |
US11232890B2 (en) * | 2018-11-06 | 2022-01-25 | Daido Steel Co., Ltd. | RFeB sintered magnet and method for producing same |
CN110444385A (zh) * | 2019-08-09 | 2019-11-12 | 浙江英洛华磁业有限公司 | 一种提升Nd-Fe-B磁体矫顽力的工艺 |
KR102632582B1 (ko) * | 2019-10-07 | 2024-01-31 | 주식회사 엘지화학 | 소결 자석의 제조 방법 |
CN115472408A (zh) * | 2021-06-10 | 2022-12-13 | 赣州市东磁稀土有限公司 | 钕铁硼磁体及其制备方法 |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2011004894A1 (ja) * | 2009-07-10 | 2011-01-13 | インターメタリックス株式会社 | NdFeB焼結磁石及びその製造方法 |
JP2014099594A (ja) * | 2012-10-17 | 2014-05-29 | Shin Etsu Chem Co Ltd | 希土類焼結磁石の製造方法及び希土類焼結磁石 |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7056393B2 (en) * | 2001-05-30 | 2006-06-06 | Neomax, Co., Ltd. | Method of making sintered compact for rare earth magnet |
US6955729B2 (en) * | 2002-04-09 | 2005-10-18 | Aichi Steel Corporation | Alloy for bonded magnets, isotropic magnet powder and anisotropic magnet powder and their production method, and bonded magnet |
JP5057111B2 (ja) * | 2009-07-01 | 2012-10-24 | 信越化学工業株式会社 | 希土類磁石の製造方法 |
JP2011216720A (ja) * | 2010-03-31 | 2011-10-27 | Nitto Denko Corp | 永久磁石及び永久磁石の製造方法 |
JP5757394B2 (ja) * | 2010-07-30 | 2015-07-29 | 日立金属株式会社 | 希土類永久磁石の製造方法 |
CN105206372A (zh) * | 2011-12-27 | 2015-12-30 | 因太金属株式会社 | NdFeB系烧结磁体 |
EP2975619A4 (en) * | 2013-03-12 | 2016-03-09 | Intermetallics Co Ltd | PROCESS FOR PRODUCING RFEB SINTERED MAGNET AND RFEB SINTERED MAGNET PRODUCED THEREBY |
CN105431915B (zh) * | 2013-08-09 | 2018-05-08 | Tdk株式会社 | R-t-b系烧结磁铁以及电机 |
CN103745823A (zh) * | 2014-01-24 | 2014-04-23 | 烟台正海磁性材料股份有限公司 | 一种R-Fe-B系烧结磁体的制备方法 |
-
2016
- 2016-01-08 JP JP2016568752A patent/JP6205511B2/ja active Active
- 2016-01-08 EP EP16735085.9A patent/EP3244426A1/en not_active Withdrawn
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- 2016-01-08 WO PCT/JP2016/050443 patent/WO2016111346A1/ja active Application Filing
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2011004894A1 (ja) * | 2009-07-10 | 2011-01-13 | インターメタリックス株式会社 | NdFeB焼結磁石及びその製造方法 |
JP2014099594A (ja) * | 2012-10-17 | 2014-05-29 | Shin Etsu Chem Co Ltd | 希土類焼結磁石の製造方法及び希土類焼結磁石 |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2018152526A (ja) * | 2017-03-15 | 2018-09-27 | インターメタリックス株式会社 | RFeB系焼結磁石の製造方法 |
JP7052201B2 (ja) | 2017-03-15 | 2022-04-12 | 大同特殊鋼株式会社 | RFeB系焼結磁石の製造方法 |
CN109148133A (zh) * | 2017-06-16 | 2019-01-04 | 中国科学院宁波材料技术与工程研究所 | 一种稀土永磁体及其制备方法 |
CN109148133B (zh) * | 2017-06-16 | 2020-11-06 | 中国科学院宁波材料技术与工程研究所 | 一种稀土永磁体及其制备方法 |
WO2023046005A1 (zh) * | 2021-09-22 | 2023-03-30 | 烟台正海磁性材料股份有限公司 | 一种高剩磁钕铁硼磁体及其制备方法和应用 |
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