JP6541038B2 - RTB based sintered magnet - Google Patents

RTB based sintered magnet Download PDF

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JP6541038B2
JP6541038B2 JP2016063822A JP2016063822A JP6541038B2 JP 6541038 B2 JP6541038 B2 JP 6541038B2 JP 2016063822 A JP2016063822 A JP 2016063822A JP 2016063822 A JP2016063822 A JP 2016063822A JP 6541038 B2 JP6541038 B2 JP 6541038B2
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大介 古澤
大介 古澤
西内 武司
武司 西内
宣介 野澤
宣介 野澤
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Hitachi Metals Ltd
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本発明はR−T−B系焼結磁石に関する。   The present invention relates to an RTB-based sintered magnet.

R−T−B系焼結磁石(Rは希土類元素うちの少なくとも一種であり、Nd及びPrの少なくとも1種を必ず含む。TはFe又はFeとCoであり、Bは硼素である)は永久磁石の中で最も高性能な磁石として知られており、ハードディスクドライブのボイスコイルモータ(VCM)、電気自動車用(EV、HV、PHVなど)モータ、産業機器用モータ、家電製品用モータなどの各種モータに使用されている。   RTB based sintered magnet (R is at least one of rare earth elements and always contains at least one of Nd and Pr. T is Fe or Fe and Co, B is boron) is permanent. It is known as the most powerful magnet among magnets, and includes voice coil motor (VCM) for hard disk drive, motor for electric car (EV, HV, PHV etc.) motor, motor for industrial equipment, motor for home appliance etc. It is used for the motor.

R−T−B系焼結磁石は、主としてR14B化合物からなる主相と、この主相の粒界部分に位置する粒界相とから構成されている。主相であるR14B化合物は高い飽和磁化と異方性磁界を持つ強磁性材料であり、R−T−B系焼結磁石の特性の根幹をなしている。 The RTB-based sintered magnet is composed of a main phase mainly composed of an R 2 T 14 B compound and a grain boundary phase located in a grain boundary portion of the main phase. The main phase R 2 T 14 B compound is a ferromagnetic material having high saturation magnetization and anisotropic magnetic field, and forms the basis of the characteristics of the RTB-based sintered magnet.

R−T−B系焼結磁石は、高温で保磁力HcJ(以下、単に「HcJ」という場合がある)が低下するため、不可逆熱減磁が起こる。そのため、特に電気自動車用モータに使用されるR−T−B系焼結磁石では、高いHcJを有することが要求されている。 In the RTB -based sintered magnet, irreversible heat demagnetization occurs because the coercivity H cJ (hereinafter sometimes simply referred to as “H cJ ”) decreases at high temperature. Therefore, in the RTB -based sintered magnet used particularly for a motor for an electric vehicle, it is required to have a high HcJ .

R−T−B系焼結磁石において、R14B化合物中のRに含まれる軽希土類元素RL(例えば、NdやPr)の一部を重希土類元素RH(例えば、DyやTb)で置換すると、HcJが向上することが知られている。RHの置換量の増加に伴い、HcJは向上する。しかし、特にDyなどのRHは、資源存在量が少ないうえ、産出地が限定されているなどの理由から、供給が安定しておらず、価格が大きく変動するなどの問題を有している。そのため、近年、RHをできるだけ使用することなく、HcJを向上させることが求められている。 In the RTB-based sintered magnet, part of the light rare earth element RL (eg, Nd or Pr) contained in R in the R 2 T 14 B compound is a heavy rare earth element RH (eg, Dy or Tb) It is known that substitution improves H cJ . H cJ improves as the amount of substitution of RH increases. However, especially RH such as Dy has problems such as unstable supply and large price fluctuation due to the small amount of resources and limited production area. Therefore, in recent years, it is required to improve H cJ without using RH as much as possible.

また、前記の通りR−T−B系焼結磁石が最も利用される用途はモータであり、特に電気自動車用モータなどの用途で高温安定性を確保するためにHcJの向上は大変有効であるが、それらの特性とともに角形比H/HcJ(以下、単に「H/HcJ」という場合がある)も高くなければならない。H/HcJが低いと減磁し易くなるという問題を引き起こす。そのため、高いHcJを有すると共に、高いH/HcJを有するR−T−B系焼結磁石が求められている。なお、R−T−B系焼結磁石の分野においては、一般に、H/HcJを求めるために測定するパラメータであるHは、J(磁化の強さ)−H(磁界の強さ)曲線の第2象限において、Jが0.9×J(Jは残留磁化、J=B)の値になる位置のH軸の読み値が用いられている。このHを減磁曲線のHcJで除した値(H/HcJ)が角形比として定義される。 In addition, as described above, the application in which the RTB -based sintered magnet is most used is a motor, and the improvement of H cJ is very effective in order to secure high-temperature stability particularly in applications such as motors for electric vehicles. However, along with their properties, the squareness ratio H k / H cJ (hereinafter sometimes simply referred to as “H k / H cJ ”) must also be high. If H k / H cJ is low, this causes a problem that demagnetization is likely to occur. Therefore, an RTB -based sintered magnet having high H cJ and high H k / H cJ is required. In the field of R-T-B based sintered magnet, typically, H k is a parameter to be measured to determine the H k / H cJ is, J (intensity of magnetization) -H (field intensity In the second quadrant of the curve, the H-axis reading of the position where J is 0.9 × J r (J r is the residual magnetization, J r = B r ) is used. A value (H k / H cJ ) obtained by dividing this H k by H cJ of the demagnetization curve is defined as a squareness ratio.

特許文献1には、Dyの含有量を抑制しつつ保磁力を高めたR−T−B系希土類焼結磁石が開示されている。この焼結磁石の組成は、一般に用いられてきたR−T−B系合金に比べてB量が相対的に少ない特定の範囲に限定され、かつ、Al、Ga、Cuのうちから選ばれる1種以上の金属元素Mを含有している。その結果、粒界にR17相が生成され、このR17相から粒界に形成される遷移金属リッチ相(R13M)の体積比率が増加することにより、HcJが向上する。 Patent Document 1 discloses an R-T-B-based rare earth sintered magnet having an increased coercive force while suppressing the content of Dy. The composition of this sintered magnet is limited to a specific range in which the amount of B is relatively small compared to the R-T-B based alloy generally used, and is selected from Al, Ga, and Cu 1 It contains metal element M of a species or more. As a result, R 2 T 17 phase is produced in the grain boundary, by the volume ratio of the R 2 T 17 transition metal-rich phase formed in the grain boundary from phase (R 6 T 13 M) increases, H cJ Improve.

国際公開第2013/008756号International Publication No. 2013/008756

特許文献1に開示されているR−T−B系希土類焼結磁石では、Dyの含有量を低減しつつ高いHcJが得られるものの、近年、電気自動車用モータ等の用途において更に高いHcJを有するR−T−B系焼結磁石が求められている。また、特許文献1に記載されているような、一般的なR−T−B系焼結磁石よりもB量を少なく(R14B型化合物の化学量論比のB量よりも少なく)し、Ga等を添加した組成の焼結磁石は、一般的なR−T−B系焼結磁石(B量がR14B型化合物の化学量論比よりも多い)と比べてH/HcJが低下するという問題点があった。特に1600kA/m以上(20kOe以上)の高いHcJを有する場合には特許文献1の表4〜表6に示されるように、角形比(特許文献1ではSq(角形性))は80%台が多く、高いレベルにあるとは言い難い。なお、特許文献1には角形比の定義は記載されていないが、特許文献1の先行技術文献として引用されている、同一出願人による特開2007−119882号公報に「磁化が飽和磁化の90%となる外部磁場の値をで割った値を%表記したもの」と記載されていることから、特許文献1の角形比の定義も同様であると思われる。つまり、特許文献1の角形比の定義は前記の一般的に用いられている定義と同様であると思われる。 The R-T-B rare earth sintered magnets disclosed in Patent Document 1, although the high H cJ while reducing the content of Dy is obtained, in recent years, higher H cJ in applications such as a motor for an electric vehicle There is a need for an RTB based sintered magnet having the Also, the amount of B is smaller than that of a general R-T-B-based sintered magnet as described in Patent Document 1 (less than the amount of B in the stoichiometric ratio of R 2 T 14 B-type compound ) And a sintered magnet of a composition to which Ga or the like is added, as compared to a general R-T-B-based sintered magnet (the amount of B is larger than the stoichiometric ratio of the R 2 T 14 B type compound) There is a problem that H k / H cJ decreases. In particular, when high H cJ of 1600 kA / m or more (20 kOe or more) is present, as shown in Tables 4 to 6 of Patent Document 1, the squareness ratio (Sq (squareness in Patent Document 1) is 80% or so It is difficult to say that there are many, high level. In addition, although the definition of the squareness ratio is not described in Patent Document 1, the same applicant cited Japanese Patent Application Laid-Open No. 2007-119882 cited by the same applicant as “prior art document of Patent Document 1”. The definition of the squareness ratio in Patent Document 1 seems to be the same because it is described as "the value obtained by dividing the value of the external magnetic field to be% by i H c ". That is, it is considered that the definition of the squareness ratio in Patent Document 1 is the same as the generally used definition described above.

本開示の実施形態は、RHの含有量を低減しつつ、高いHcJと高いH/HcJを有するR−T−B系焼結磁石を提供する。 Embodiments of the present disclosure provide RTB -based sintered magnets having high H cJ and high H k / H cJ while reducing the content of RH.

本開示のR−T−B系焼結磁石は、R(RはR1とR2とからなり、R1はDy、Tb、Gd及びHoを除く希土類元素のうち少なくとも一種でありNd及び/又はPrを必ず含む、R2はDy、Tb、Gd及びHoの少なくとも一種であり、R−T−B系焼結磁石全体の1.5質量%以下である):32.0質量%以上、34.0質量%以下、
B:0.88質量%以上、0.92質量%以下、
Ga:0.60質量%以上、1.10質量%以下、
Cu:0.20質量%以上、0.35質量%以下、
Ti:0.05質量%以上、0.13質量%以下、
Al:0.05質量%以上、0.50質量%以下、
を含有し、残部T(TはFe又はFeとCo)及び不可避的不純物からなり、且つ、下記式(1)を満足する組成を有する。
14.4≦[(Fewt/Feat)+(Cowt/Coat)+(Alwt/Alat)]/[(Bwt/Bat)−2×(Tiwt/Tiat)]≦15.4 (1)
(FewtはFeの質量%の値であり、FeatはFeの原子量の値であり、CowtはCoの質量%の値であり、CoatはCoの原子量の値であり、AlwtはAlの質量%の値であり、AlatはAlの原子量の値であり、BwtはBの質量%の値であり、BatはBの原子量の値であり、TiwtはTiの質量%の値であり、TiatはTiの原子量の値である)
The RTB-based sintered magnet of the present disclosure comprises R (R is composed of R 1 and R 2, R 1 is at least one of rare earth elements excluding Dy, Tb, Gd and Ho, and Nd and / or Pr Indispensably, R2 is at least one of Dy, Tb, Gd and Ho, and is 1.5% by mass or less of the whole RTB based sintered magnet): 32.0% by mass or more, 34.0% %Less than,
B: 0.88 mass% or more, 0.92 mass% or less,
Ga: 0.60 mass% or more, 1.10 mass% or less,
Cu: 0.20 mass% or more, 0.35 mass% or less,
Ti: 0.05% by mass or more and 0.13% by mass or less,
Al: 0.05% by mass or more, 0.50% by mass or less,
And a balance T (T is Fe or Fe and Co) and unavoidable impurities, and has a composition satisfying the following formula (1).
14.4 ≦ [(Fe wt / Fe at ) + (Co wt / Co at ) + (Al wt / Al at )] / [(B wt / B at ) −2 × (Ti wt / Ti at )] ≦ 15.4 (1)
(Fe wt is a value of mass% of Fe, Fe at is a value of atomic weight of Fe, Co wt is a value of mass% of Co, Co at is a value of atomic weight of Co, Al wt is It is a value of mass% of Al, Al at is a value of atomic weight of Al, B wt is a value of mass% of B, B at is a value of atomic weight of B, and Ti wt is a mass% of Ti Where Ti at is the atomic weight value of Ti)

ある実施形態において、前記Rの含有量が33.0質量%以上、34.0質量%以下である。   In one embodiment, the content of R is 33.0% by mass or more and 34.0% by mass or less.

ある実施形態において、前記Gaの含有量が0.70質量%超、1.10質量%以下である。   In one embodiment, the content of Ga is more than 0.70% by mass and 1.10% by mass or less.

ある実施形態において、前記組成がさらに下記式(2)を満足する。
14.8≦[(Fewt/Feat)+(Cowt/Coat)+(Alwt/Alat)]/[(Bwt/Bat)−2×(Tiwt/Tiat)]≦15.4 (2)
In one embodiment, the composition further satisfies the following formula (2).
14.8 ≦ [(Fe wt / Fe at ) + (Co wt / Co at ) + (Al wt / Al at )] / [(B wt / B at ) −2 × (Ti wt / Ti at )] ≦ 15.4 (2)

ある実施形態において、前記Rは、Dy、Tb、Gd及びHoをいずれも含有しない。   In one embodiment, R does not contain any of Dy, Tb, Gd and Ho.

ある実施形態において前記R−T−B系焼結磁石の酸素量が0.2質量%以下である。   In one embodiment, the oxygen content of the RTB-based sintered magnet is 0.2% by mass or less.

本開示の実施形態によると、RHの含有量を低減しつつ、高いHcJと高いH/HcJを有するR−T−B系焼結磁石を提供することができる。 According to an embodiment of the present disclosure, an RTB -based sintered magnet having high H cJ and high H k / H cJ can be provided while reducing the content of RH.

試料No.2〜6におけるTi量とHcJの関係を示すグラフである。Sample No. It is a graph which shows the relationship between the amount of Ti in 2-6, and HcJ . 試料No.2〜6におけるTi量とBの関係を示すグラフである。Sample No. Is a graph showing the relationship between the Ti content and B r at 2-6. 試料No.2及び試料No.7〜9におけるB量とHcJの関係を示すグラフである。Sample No. 2 and sample no. It is a graph which shows the relationship between B amount and HcJ in 7-9. 試料No.2及び試料No.7〜9におけるB量とH/HcJの関係を示すグラフである。Sample No. 2 and sample no. It is a graph showing the relationship between the B content and H k / H cJ at 7-9. 試料No.2及び試料No.10、11におけるTRE量とHcJの関係を示すグラフである。Sample No. 2 and sample no. It is a graph which shows the relationship between the amount of TRE and HcJ in 10 and 11. 試料No.2及び試料No.12〜14におけるGa量とHcJの関係を示すグラフである。Sample No. 2 and sample no. It is a graph which shows the amount of Ga in 12-14, and the relationship of HcJ . 試料No.2及び試料No.15、16におけるCu量とHcJの関係を示すグラフである。Sample No. 2 and sample no. It is a graph which shows the relationship between the amount of Cu in 15, 16 and HcJ . 試料No.17〜20における式(1)及び式(2)とHcJの関係を示すグラフである。Sample No. It is a graph which shows the relationship of Formula (1) in Formula 17 and Formula (2), and HcJ in 17-20 .

本発明者らは検討の結果、特定範囲のTi及びBを用い、前記式(1)を満たすことで、製造工程中にTiの硼化物を生成させることにより、R−T−B系焼結磁石全体のB量からTiの硼化物生成により消費されたB量を差し引いたB量、言い替えると、Tiと硼化物を生成しなかった残りのB量(以下、「有効B量」又は「Beff量」と記載することがある)を一般的なR−T−B系焼結磁石全体のB量より少なく(R14B型化合物の化学量論比のB量よりも少なく)した上で、さらに、R、Ga、Cuを比較的多く添加した組成のR−T−B系焼結磁石は、高いHcJを有すると共に高いH/HcJを有することを見出した。これは、R−T−Ga相及び/又はR−T−Ga−Cu相を比較的多く生成させることができるからだと考えられる。これにより高いHcJを得ることができる。また、本発明者らの検討の結果、Tiの硼化物、R−T−Ga相及びR−T−Ga−Cu相は原料段階では生成され難く、その後の焼結時や熱処理時に生成され易いことが分かった。そのため、原料段階から既にB量が少ない場合は、原料の段階でR−T−Ga相やR−T−Ga−Cu相はあまり生成せずにR17相等の異相が生成し、それにより得られたR−T−B系焼結磁石のH/HcJが低下すると考えられる。すなわち、特許文献1は、B量を少なくして原料合金中(R−T−B系合金中)にR17相を生成させているため、H/HcJが低下していると考えられる。これに対し本開示の実施形態は、Tiを用いて主に焼結時や熱処理時にTiの硼化物(典型的には、TiB)を生成させることで前記Beff量を一般的なR−T−B系焼結磁石全体のB量よりも少なくすることができるため、原料段階におけるB量を多くすることができる。これにより原料段階におけるR17相等の異相の生成を抑制することができ、高いH/HcJを有するR−T−B系焼結磁石を得ることができると考えられる。更に、本発明者らは検討の結果、原料のB量が多すぎると、そのB量に見合ったTi量が必要となり、焼結磁石中でのTiの硼化物の体積比率が増加して主相の体積比率が低下したり、主相中のTi濃度が高くなるなどにより、Bの低下を招くことが分かった。よって、原料段階で異相が出ない最小限のB量に設定し、Tiを必要最小限添加する。これにより、Bの低下を抑制しつつ高いH/HcJを有するR−T−B系焼結磁石を得ることができると考えられる。 As a result of investigations, the present inventors use Ti and B in a specific range and satisfy the above-mentioned formula (1), thereby generating a boride of Ti during the manufacturing process, thereby making the RTB-based sintering The amount of B which deducted the amount of B consumed by boride formation of Ti from the amount of B of the whole magnet, in other words, the remaining amount of B which did not form boride with Ti (hereinafter, “effective B amount” or “B The amount of “ eff ” may be described as “the amount of B” of the entire R-T-B sintered magnet as a whole (less than the amount of B of the stoichiometric ratio of R 2 T 14 B type compound) Above, it was further found that an RTB -based sintered magnet having a composition in which R, Ga, and Cu are added relatively frequently has high H cJ and high H k / H cJ . It is considered that this is because relatively large amounts of RT-Ga phase and / or RT-Ga-Cu phase can be generated. Thereby, high H cJ can be obtained. Moreover, as a result of studies by the present inventors, the boride of Ti, R-T-Ga phase and R-T-Ga-Cu phase are hard to be generated at the raw material stage, and are easily generated at the time of subsequent sintering and heat treatment I found that. Therefore, when the amount of B is already small from the raw material stage, R-T-Ga phase and R-T-Ga-Cu phase are not generated so much at the raw material stage, but different phase such as R 2 T 17 phase is generated. It is considered that H k / H cJ of the RTB -based sintered magnet obtained by the above decreases. That is, in Patent Document 1, when the amount of B is reduced and the R 2 T 17 phase is generated in the raw material alloy (in the RTB -based alloy), it is assumed that H k / H cJ is lowered. Conceivable. On the other hand, the embodiment of the present disclosure uses Ti to generate a boride of Ti (typically, TiB 2 ) mainly at the time of sintering or at the time of heat treatment, so that the amount of B eff can be generally R The amount of B in the raw material stage can be increased because the amount of B can be made smaller than the whole of the T-B based sintered magnet. It is thought that this can suppress the formation of heterophases such as the R 2 T 17 phase in the raw material stage, and can obtain an RTB -based sintered magnet having high H k / H cJ . Furthermore, as a result of investigations, the inventors of the present invention have found that if the amount of B in the raw material is too large, the amount of Ti corresponding to the amount of B is required, and the volume ratio of the boride of Ti in the sintered magnet increases. or it reduces the volume ratio of the phases, such as by Ti concentration in the main phase is high, it has been found that lowering the B r. Therefore, the B content is set to a minimum amount of B that does not generate a different phase in the raw material stage, and Ti is added as necessary. Thereby, it is considered that an RTB -based sintered magnet having a high H k / H cJ can be obtained while suppressing a decrease in B r .

[組成等の限定理由について]
(R)
RはR1とR2とからなり、R1はDy、Tb、Gd及びHoを除く希土類元素のうち少なくとも一種でありNd及び/又はPrを必ず含む、R2はDy、Tb、Gd及びHoの少なくとも一種であり、R−T−B系焼結磁石全体の1.5質量%以下である。Rの含有量は32.0質量%以上、34.0質量%以下である。Rが32.0質量%未満であると高いHcJが得られない恐れがある。一方、Rが34.0質量%を超えても本開示の実施形態の効果を得ることができるが、焼結体の製造工程中における合金粉末が非常に活性になり、合金粉末の著しい酸化や発火などが生じたり、得られたR−T−B系焼結磁石のBが大幅に低下したり、耐食性が悪化する可能性があるため、34.0質量%以下が好ましい。Rは33.0質量%以上、34.0質量%以下であることがより好ましい。重希土類元素であるR2(Dy、Tb、Gd及びHoの少なくとも一種)の含有量は、R−T−B系焼結磁石全体の1.5質量%以下である。本開示の実施形態は重希土類元素を含有しなくても高いBと高いHcJ を得ることができるため、より高いHcJ を求められる場合でも重希土類元素の含有量を削減できる。好ましくは、Rは、R2(Dy、Tb、Gd及びHo)を含有しない。
[About the reasons for limitation such as composition]
(R)
R is composed of R 1 and R 2, R 1 is at least one of rare earth elements except Dy, Tb, Gd and Ho and necessarily contains Nd and / or Pr, R 2 is at least one of Dy, Tb, Gd and Ho And 1.5% by mass or less of the whole RTB-based sintered magnet. The content of R is 32.0% by mass or more and 34.0% by mass or less. If R is less than 32.0% by mass, high H cJ may not be obtained. On the other hand, although the effect of the embodiment of the present disclosure can be obtained even if R exceeds 34.0 mass%, the alloy powder becomes very active during the manufacturing process of the sintered body, and significant oxidation of the alloy powder or it is or generated or fire, B r of R-T-B based sintered magnet is lowered significantly obtained, because there is a possibility that the corrosion resistance is deteriorated, preferably 34.0 mass% or less. R is more preferably 33.0% by mass or more and 34.0% by mass or less. The content of the heavy rare earth element R2 (at least one of Dy, Tb, Gd and Ho) is at most 1.5% by mass of the entire RTB-based sintered magnet. The embodiment of the present disclosure can obtain high B r and high H cJ without containing a heavy rare earth element, and therefore can reduce the content of the heavy rare earth element even when higher H cJ can be obtained. Preferably, R does not contain R2 (Dy, Tb, Gd and Ho).

(B)
Bの含有量は、0.88質量%以上、0.92質量%以下である。Bが0.88質量%未満であるとHが著しく低下する恐れがある。一方、Bが0.92質量%を超えるとR−T−Ga相及びR−T−Ga−Cu相の生成量が少なすぎて高いHcJが得られない恐れがある。Bの含有量を上記範囲とし、Tiの範囲を後述する範囲とするとともに下記式(1)を満足することにより、高いH/HcJを得ることができる。
(B)
Content of B is 0.88 mass% or more and 0.92 mass% or less. If B is less than 0.88% by mass, H k may be significantly reduced. On the other hand, if B exceeds 0.92% by mass, the generation amounts of the R-T-Ga phase and the R-T-Ga-Cu phase may be too small to obtain high HcJ . The content of B is within the above range, by satisfying the following formula (1) together with the range to be described later range of Ti, it is possible to obtain a high H k / H cJ.

(Ga)
Gaの含有量は、0.60質量%以上、1.10質量%以下である。Bを上記範囲とし、且つ、Cu、Tiを後述する範囲とし、式(1)を満足した上でGaを0.60質量%以上、1.10質量%以下含有させることによりR−T−Ga相を比較的多く生成させることができ、高いHcJを得ることができる。Gaが0.60質量%未満であるとR−T−Ga相及びR−T−Ga−Cu相の生成量が少なすぎて高いHcJが得られない。一方、Gaが1.10質量%を超えると不要なGaが存在してBが低下する恐れがある。Gaは、0.70質量%超、1.10質量%以下であることが好ましい。より高いHcJを得ることができる。ここでR−T−Ga相及びR−T−Ga−Cu相の典型例としてR13Ga化合物及びGaの一部がCuで置換されたNdFe13(Ga,Cu)化合物が挙げられる。また、R13Ga化合物及びNdFe13(Ga,Cu)化合物はLaCo11Ga型結晶構造を有する。R13Ga化合物はその状態によってはR13−δGa1+δ化合物の状態にある場合があり得る。R−T−B系焼結磁石中にCu、Al及びSiが比較的多く含有される場合、R−T−Ga相は、R13−δ(Ga1−x−y−zCuAlSi1+δであり得る。
(Ga)
The content of Ga is 0.60% by mass or more and 1.10% by mass or less. R-T-Ga by making B into the above-mentioned range and making Cu, Ti into a range to be described later, and by containing Ga 0.60 mass% or more and 1.10 mass% or less after satisfying the formula (1) A relatively large number of phases can be generated, and high H cJ can be obtained. If the content of Ga is less than 0.60% by mass, the amounts of R-T-Ga phase and R-T-Ga-Cu phase formed are too small to obtain high HcJ . On the other hand, Ga is the B r unnecessary Ga is present exceeds 1.10 mass% may decrease. Ga is preferably more than 0.70% by mass and 1.10% by mass or less. Higher H cJ can be obtained. Here, as typical examples of the R-T-Ga phase and the R-T-Ga-Cu phase, an R 6 T 13 Ga compound and an Nd 6 Fe 13 (Ga, Cu) 1 compound in which part of Ga is substituted with Cu are used. It can be mentioned. The R 6 T 13 Ga compound and the Nd 6 Fe 13 (Ga, Cu) 1 compound have a La 6 Co 11 Ga 3 type crystal structure. Depending on its state, the R 6 T 13 Ga compound may be in the state of R 6 T 13-δ Ga 1 + δ compound. When relatively large amounts of Cu, Al and Si are contained in the R-T-B based sintered magnet, the R-T-Ga phase is formed by R 6 T 13-δ (Ga 1-x-y-z Cu x It may be Al y Si z ) 1 + δ .

(Cu)
Cuの含有量は、0.20質量%以上、0.35質量%以下である。Cuが0.20質量%未満であると高いHcJが得られない恐れがある。一方、Cuが0.35質量%を超えると不要なCuが存在してBが大幅に低下する恐れがある。
(Cu)
The content of Cu is 0.20% by mass or more and 0.35% by mass or less. If Cu is less than 0.20% by mass, high H cJ may not be obtained. On the other hand, Cu is the B r unnecessary Cu is present exceeds 0.35 mass% may decrease significantly.

(Ti)
Tiの含有量は、0.05質量%以上、0.13質量%以下である。Tiを含有することによりTiの硼化物を生成し、且つ、後述する式(1)を満たすことで、主に焼結時や熱処理時に前記Beff量を一般的なR−T−B系焼結磁石全体のB量より少なくする。これにより、高いH/HcJを有するR−T−B系焼結磁石を得ることができる。Tiが0.05質量%未満であると高いHcJを得ることができず、また高いH/HcJを得ることができない恐れがある。一方、Tiが0.13質量%を超えるとBが低下するとともに高いH/HcJを得ることができない恐れがある。
(Ti)
The content of Ti is 0.05% by mass or more and 0.13% by mass or less. By forming a boride of Ti by containing Ti, and satisfying the formula (1) described later, the B eff amount is generally reduced during general sintering or heat treatment. Make it less than the B amount of the whole of the magnet. Thereby, an RTB -based sintered magnet having high H k / H cJ can be obtained. If Ti is less than 0.05% by mass, high H cJ can not be obtained, and high H k / H cJ may not be obtained. On the other hand, there is a fear that Ti can not obtain a high H k / H cJ with B r decreases exceeds 0.13 mass%.

(Al)
更に、通常含有される程度のAl(0.05質量%以上、0.50質量%以下)を含有する。Alを含有することによりHcJを向上させることができる。Alは通常、製造工程中で不可避的不純物として0.05質量%以上含有されるが、不可避的不純物で含有される量と意図的に添加した量の合計で0.50質量%以下含有する。
(Al)
Furthermore, it contains Al (0.05% by mass or more and 0.50% by mass or less) to the extent normally contained. H cJ can be improved by containing Al. Although Al is usually contained as 0.05% by mass or more as an unavoidable impurity in the production process, it is 0.50% by mass or less in the total of the amount contained as the unavoidable impurity and the amount intentionally added.

(残部T)
残部はT(TはFe又はFeとCo)であり、Tは、式(1)を満足する。質量比でTの90%以上がFeであることが好ましい。Feの一部をCoで置換することができる。但し、Coの置換量が、質量比でT全体の10%を超えるとBrが低下するため好ましくない。さらに、本開示の実施形態のR−T−B系焼結磁石は、ジジム合金(Nd−Pr)、電解鉄、フェロボロンなどの合金中及び製造工程中に通常含有される不可避的不純物並びに少量の上記以外の元素(上記R、B、Ga、Cu、Ti、Al以外の元素)を含有してもよい。例えば、V、Cr、Mn、Ni、Si、La、Ce、Sm、Ca、Mg、O(酸素)、N(炭素)、C(窒素)、Zr、Nb、Mo、Hf、Ta、W、Inなどをそれぞれ含有してもよい。但し、O(酸素)量は、0.2質量%以下が好ましい。酸素を多く含有しすぎるとRの一部が酸素と結合することにより、磁石中で有効に活用されるR量が減少し、高いHcJが得られない恐れがある。
(Remaining part T)
The balance is T (T is Fe or Fe and Co), and T satisfies the formula (1). It is preferable that 90% or more of T in mass ratio is Fe. A part of Fe can be replaced by Co. However, the substitution amount of Co is greater than 10% of the total T by mass ratio is not preferable because the B r drops. Furthermore, the RTB-based sintered magnet according to the embodiment of the present disclosure includes unavoidable impurities and small amounts of impurities usually contained in alloys such as didymium alloy (Nd-Pr), electrolytic iron, ferroboron, etc. Elements other than the above (elements other than the above R, B, Ga, Cu, Ti, and Al) may be contained. For example, V, Cr, Mn, Ni, Si, La, Ce, Sm, Ca, Mg, O (oxygen), N (carbon), C (nitrogen), Zr, Nb, Mo, Hf, Ta, W, In Each may be contained. However, the amount of O (oxygen) is preferably 0.2% by mass or less. If too much oxygen is contained, a part of R bonds to oxygen, which may reduce the amount of R effectively utilized in the magnet, and high H cJ may not be obtained.

(式(1)及び式(2))
式(1)を満足することにより、前記Beff量を一般的なR−T−B系焼結磁石のB量より少なく(R14B型化合物の化学量論比のB量よりも少なく)する。
前記Beff量がR14B型化合物の化学量論比を下回ると、Feと、主相のFeサイトを容易に置換することができるCo、Alの和が余剰となる(すなわち、前記Beffに対する、FeとCoとAlの合計の比がR14B型化合物のB量とT量の化学量論比(=14)よりも大きくなる)。よって、全てのTiがTiBになった場合、前記Beff量をR14B型化合物の化学量論比のB量よりも少なくするためには、[(Fewt/Feat)+(Cowt/Coat)+(Alwt/Alat)]/[(Bwt/Bat)−2×(Tiwt/Tiat)]が14よりも大きい(FeとCoとAlが余剰になる)必要がある。そして、さらにBeffに対する、FeとCoとAlの合計の比が14.4以上、15.4以下であることを規定しているのが式(1)である。14.4以上、15.4以下とすることにより、R−T−Ga相を適切に生成させることができ、高いHcJを得ることができる。14.4未満であると、R−T−Ga相の生成量が少なくなり、高いHcJが得られない恐れがある。一方、15.4超であると、主相やR−T−Ga相以外のFeリッチな相(R17相など)の量が増加し、高いHcJを得られない恐れがある。好ましくは、さらに式(2)を満足する。式(2)は式(1)の下限の値(14.4)を更に引き上げたものである。式(2)を満たすことによりさらに高いHcJを得ることができる。尚、式(1)及び式(2)におけるFewtはFeの質量%の値であり、FeatはFeの原子量の値であり、CowtはCoの質量%の値であり、CoatはCoの原子量の値であり、AlwtはAlの質量%の値であり、AlatはAlの原子量の値であり、BwtはBの質量%の値であり、BatはBの原子量の値であり、TiwtはTiの質量%の値であり、TiatはTiの原子量の値である。
(Formula (1) and Formula (2))
By satisfying the formula (1), the amount of B eff is smaller than the amount of B of a general R-T-B-based sintered magnet (the amount of B of the stoichiometric ratio of R 2 T 14 B-type compound is Reduce.
When the B eff amount is less than the stoichiometric ratio of the R 2 T 14 B type compound, the sum of Fe and Co and Al capable of easily replacing the Fe site of the main phase becomes surplus (ie, the above The ratio of the total of Fe, Co, and Al to B eff is larger than the stoichiometric ratio (= 14) of the amounts of B and T of the R 2 T 14 B-type compound). Therefore, when all the Ti becomes TiB 2 , in order to make the amount of B eff smaller than the amount of B of the stoichiometric ratio of the R 2 T 14 B type compound, [(Fe wt / Fe at ) + (Co wt / Co at ) + (Al wt / Al at )] / [(B wt / B at ) -2 × (Ti wt / Ti at )] is larger than 14 (Fe, Co and Al are surplus Needs to be Further, formula (1) defines that the ratio of the total of Fe, Co and Al to B eff is 14.4 or more and 15.4 or less. By setting it as 14.4 or more and 15.4 or less, R-T-Ga phase can be generated appropriately and high HcJ can be obtained. If it is less than 14.4, the generation amount of the R-T-Ga phase may be small, and high H cJ may not be obtained. On the other hand, if it exceeds 15.4, the amount of Fe-rich phases (such as R 2 T 17 phase) other than the main phase and R-T-Ga phase may increase, and high H cJ may not be obtained. Preferably, the formula (2) is further satisfied. Formula (2) further raises the value (14.4) of the lower limit of Formula (1). By satisfying the formula (2), it is possible to obtain even higher H cJ . In the formulas (1) and (2), Fe wt is a value of mass% of Fe, Fe at is a value of atomic weight of Fe, Co wt is a value of mass% of Co, and Co at is The atomic weight value of Co, Al wt is the value of mass% of Al, Al at is the value of atomic weight of Al, B wt is the value of mass% of B, and B at is the atomic weight of B It is a value, Ti wt is a value of the mass% of Ti, Ti at is a value of the atomic weight of Ti.

[R−T−B系焼結磁石の製造方法]
本開示のR−T−B系焼結磁石は、公知の製造方法を用いて作製することができる。
公知の製造方法の一例を説明する。公知の製造方法は、合金粉末を得る工程、成形工程、焼結工程、熱処理工程を有する。以下、各工程について説明する。
[Method of producing RTB based sintered magnet]
The RTB-based sintered magnet of the present disclosure can be manufactured using a known manufacturing method.
An example of a well-known manufacturing method is demonstrated. The known manufacturing method has a step of obtaining an alloy powder, a forming step, a sintering step, and a heat treatment step. Each step will be described below.

(1)合金粉末を得る工程
合金粉末は、1種類の合金粉末(単合金粉末)を用いてもよいし、2種類以上の合金粉末を混合することにより合金粉末(混合合金粉末)を得る、いわゆる2合金法を用いてもよい。単合金粉末の場合、所定の組成となるようにそれぞれの元素の金属又は合金を準備し、これらにストリップキャスティング法等を適用して、フレーク状の合金を製造する。得られたフレーク状の原料合金を水素粉砕し、粗粉砕粉のサイズを例えば1.0mm以下とする。次に、粗粉砕粉をジェットミル等により微粉砕することで、例えば粒径D50(気流分散法によるレーザー回折法で得られた体積基準メジアン径)が3μm以上、7μm以下の微粉砕粉(単合金粉末)を得る。なお、ジェットミル粉砕前の粗粉砕粉、ジェットミル粉砕中及びジェットミル粉砕後の合金粉末に助剤として公知の潤滑剤を使用してもよい。混合合金粉末を用いる場合、2種以上の合金粉末を所定の組成となるようにそれぞれの元素の金属又は合金を準備し、上述した単合金粉末の場合と同様に、まずストリップキャスティング法によりフレーク状の合金を製造し、次にフレーク状の合金を水素粉砕し粗粉砕粉末を得る。得られた2種以上の合金粉末をV型混合機等に投入して混合し、混合合金粉末を得る。尚、混合合金粉末を用いる場合、混合合金粉末の組成が本開示の組成範囲内となるように調整する。このように粗粉砕粉末の段階で混合した場合は、得られた混合合金粉末をジェットミル等により微粉砕し微粉砕粉末となし混合合金粉末を得る。もちろん、2種以上の合金粉末をそれぞれジェットミル等により微粉砕し微粉砕粉末となした後混合し混合合金粉末を得てもよい。尚、Tiは、合金粉末に含有されてもよいし、Tiの全部又は一部を含む原料合金の粗粉砕粉あるいは微粉砕粉にTiの金属の粉末あるいはTiを含む合金や化合物の粉末を添加してもよい。
(1) Step of obtaining alloy powder As the alloy powder, one kind of alloy powder (single alloy powder) may be used, or an alloy powder (mixed alloy powder) may be obtained by mixing two or more kinds of alloy powders. A so-called two-alloy method may be used. In the case of a single alloy powder, a metal or an alloy of each element is prepared to have a predetermined composition, and a strip casting method or the like is applied to these to produce a flake-like alloy. The obtained flake-like raw material alloy is subjected to hydrogen grinding, and the size of the roughly ground powder is adjusted to, for example, 1.0 mm or less. Next, the coarsely pulverized powder is finely pulverized by a jet mill or the like to obtain, for example, finely pulverized powder (single particle diameter D50 (volume-based median diameter obtained by laser diffraction method by air flow dispersion method) 3 μm or more and 7 μm or less Alloy powder is obtained. Lubricants known in the art may be used as auxiliary agents for coarsely pulverized powder before jet milling and alloy powder during jet milling and after jet milling. In the case of using a mixed alloy powder, a metal or an alloy of each element is prepared so that two or more alloy powders have a predetermined composition, and flakes are first formed by a strip casting method as in the case of the single alloy powder described above. The alloy in the form of is then produced, and then the flake-like alloy is subjected to hydrogen grinding to obtain a roughly ground powder. The obtained two or more types of alloy powders are put into a V-type mixer and the like and mixed to obtain a mixed alloy powder. In addition, when using mixed alloy powder, it adjusts so that the composition of mixed alloy powder may become in the composition range of this indication. Thus, when mixed at the stage of coarsely pulverized powder, the obtained mixed alloy powder is pulverized by a jet mill or the like to obtain a pulverized powder and a mixed alloy powder. Of course, two or more types of alloy powders may be finely pulverized by a jet mill or the like to form finely pulverized powders, which may then be mixed to obtain a mixed alloy powder. Ti may be contained in the alloy powder, or a powder of Ti metal or a powder of an alloy or compound containing Ti is added to a coarsely pulverized powder or finely pulverized powder of a raw material alloy containing all or part of Ti. You may

(2)成形工程
得られた合金粉末(単合金粉末又は混合合金粉末)を用いて磁界中成形を行い、成形体を得る。磁界中成形は、金型のキャビティー内に乾燥した合金粉末を挿入し、磁界を印加しながら成形する乾式成形法、金型のキャビティー内にスラリー(分散媒中に合金粉末が分散している)を注入し、スラリーの分散媒を排出しながら成形する湿式成形法を含む既知の任意の磁界中成形方法を用いてよい。
(2) Forming Step The obtained alloy powder (single alloy powder or mixed alloy powder) is used for forming in a magnetic field to obtain a formed body. In the magnetic field molding, dry alloy powder is inserted into the cavity of the mold, and dry molding is performed while applying a magnetic field, and the slurry (the alloy powder is dispersed in the dispersion medium) in the cavity of the mold. Any known magnetic field molding method may be used, including a wet molding method of injecting and molding while discharging the dispersion medium of the slurry.

(3)焼結工程
成形体を焼結することにより焼結体を得る。成形体の焼結は公知の方法を用いることができる。なお、焼結時の雰囲気による酸化を防止するために、焼結は真空雰囲気中又は雰囲気ガス中で行うことが好ましい。雰囲気ガスは、アルゴンなどの不活性ガスを用いることが好ましい。
(3) Sintering process A sintered body is obtained by sintering a molded body. A known method can be used to sinter the shaped body. In addition, in order to prevent the oxidation by the atmosphere at the time of sintering, it is preferable to perform sintering in vacuum atmosphere or atmosphere gas. It is preferable to use an inert gas such as argon as the atmosphere gas.

(4)熱処理工程
得られた焼結体に対し、磁気特性を向上させることを目的とした熱処理を行うことが好ましい。熱処理温度、熱処理時間などは公知の条件を採用することができる。例えば、比較的低い温度(400℃以上600℃以下)のみでの熱処理(一段熱処理)、あるいは比較的高い温度(700℃以上焼結温度以下(例えば1050℃以下))で熱処理を行った後比較的低い温度(400℃以上600℃以下)で熱処理する(二段熱処理)などの条件を採用することができる。好ましい条件としては、730℃以上1020℃以下で5分から500分程度の熱処理を施し、冷却後(室温又は440℃以上550℃以下まで冷却後)、さらに440℃以上550℃以下で5分から500分程度熱処理することが挙げられる。熱処理雰囲気は、真空雰囲気あるいは不活性ガス(アルゴンなど)で行うことが好ましい。
得られた焼結磁石に磁石寸法の調整のため、研削などの機械加工を施してもよい。その場合、熱処理は機械加工前でも機械加工後でもよい。さらに、得られた焼結磁石に、表面処理を施してもよい。表面処理は、公知の手法で良く、例えばAl蒸着や電気Niめっきや樹脂塗装などを採用することができる。
(4) Heat Treatment Step The obtained sintered body is preferably subjected to a heat treatment for the purpose of improving the magnetic properties. Known conditions can be adopted for the heat treatment temperature, heat treatment time and the like. For example, comparison is performed after heat treatment at a relatively low temperature (400 ° C. or more and 600 ° C. or less) (one-step heat treatment) or heat treatment at a relatively high temperature (700 ° C. or more and sintering temperature or less (eg, 1050 ° C. or less)) Conditions such as heat treatment (two-step heat treatment) at a very low temperature (400.degree. C. or more and 600.degree. C. or less) can be employed. As preferable conditions, a heat treatment of about 5 minutes to 500 minutes is performed at 730 ° C. to 1020 ° C., and after cooling (after cooling to room temperature or 440 ° C. to 550 ° C.), 5 minutes to 500 minutes at 440 ° C. to 550 ° C. Some degree of heat treatment may be mentioned. The heat treatment atmosphere is preferably performed in a vacuum atmosphere or an inert gas (such as argon).
The obtained sintered magnet may be subjected to machining such as grinding to adjust the size of the magnet. In that case, the heat treatment may be before or after machining. Furthermore, surface treatment may be applied to the obtained sintered magnet. The surface treatment may be a known method, and for example, Al deposition, electric Ni plating, resin coating or the like can be adopted.

本開示の実施形態を実施例によりさらに詳細に説明するが、本開示の実施形態はそれらに限定されるものではない。   The embodiments of the present disclosure will be described in more detail by way of examples, but the embodiments of the present disclosure are not limited thereto.

<実験例1>
電解鉄、Ndメタル、Prメタル、フェロボロン合金、電解Co、Alメタル、Cuメタル及びGaメタルを用いて(メタルはいずれも純度99%以上)、Ti以外の組成が表1の試料No.1〜16に示すR−T−B系焼結磁石の組成となるように配合し、それらの原料を溶解してストリップキャスト法により鋳造し、厚み0.2mm以上、0.4mm以下のフレーク状の原料合金を得た。得られたフレーク状の原料合金を水素加圧雰囲気で水素脆化させた後、550℃まで真空中で加熱、冷却する脱水素処理を施し、粗粉砕粉を得た。次に、得られた粗粉砕粉に、潤滑剤としてステアリン酸亜鉛を粗粉砕粉100質量%に対して0.035質量%添加、混合した後、気流式粉砕機(ジェットミル装置)を用いて、窒素流気中で乾式粉砕し、粒径D50が4μmの微粉砕粉(合金粉末)を得た。なお、本実験例では、粉砕時の窒素ガス中の酸素濃度を50ppm以下とすることにより、最終的に得られる焼結磁石の酸素量が0.1質量%前後となるようにした。また、粒径D50は、気流分散法によるレーザー回折法で得られた値(体積基準メジアン径)である。
前記微粉砕粉に、粒径D50が10μm以下のTiH粉末を0〜0.21質量%の範囲内で添加し、さらに潤滑剤としてステアリン酸亜鉛を微粉砕粉100質量%に対して0.05質量%添加、混合した後、磁界中で成形し、成形体を得た。なお、成形装置には、磁界印加方向と加圧方向とが直行する、いわゆる直角磁界成形装置(横磁界成形装置)を用いた。
得られた成形体を、真空中で1030℃以上、1050℃以下(試料ごとに焼結による緻密化が十分起こる温度を選定)で4時間保持して焼結し、R−T−B系焼結磁石を得た。R−T−B系焼結磁石の密度はいずれも7.5Mg/m以上であった。焼結後のR−T−B系焼結磁石に、真空中で900℃で2時間保持した後室温まで冷却し、次いで真空中で500℃で2時間保持した後、室温まで冷却する熱処理を施した。得られたR−T−B系焼結磁石の成分の分析結果を表1に示す。なお、表1におけるFe、Nd、Pr、Dy、B、Co、Al、Cu、Ga及びTiは、高周波誘導結合プラズマ発光分光分析法(ICP−OES)を使用して測定した。また、O(酸素量)は、ガス融解−赤外線吸収法、N(窒素量)は、ガス融解−熱伝導法、C(炭素量)は、燃焼−赤外線吸収法、によるガス分析装置を使用して測定した。また、表1において、TREは全てのRの量(Nd、Pr、Dy)を合計した値(以下同様)である。
Experimental Example 1
Using electrolytic iron, Nd metal, Pr metal, ferroboron alloy, electrolytic Co, Al metal, Cu metal and Ga metal (all metals have a purity of 99% or more), the composition of sample No. 1 in Table 1 other than Ti is used. Compounded so as to become the composition of RTB based sintered magnet shown in 1 to 16, melt those raw materials, cast by strip casting method, flake shape with a thickness of 0.2 mm or more and 0.4 mm or less The raw material alloy was obtained. The obtained flake-like raw material alloy was subjected to hydrogen embrittlement in a hydrogen pressurized atmosphere, and then subjected to dehydrogenation treatment of heating and cooling in vacuum to 550 ° C. to obtain roughly crushed powder. Next, to the obtained coarsely pulverized powder, 0.035% by mass of zinc stearate as a lubricant is added with respect to 100% by mass of the coarsely pulverized powder and mixed, and then using an air flow crusher (jet mill apparatus) was dry milled in a nitrogen Nagareki, the particle size D 50 was obtained finely pulverized powder of 4μm (the alloy powder). In the present experimental example, by setting the oxygen concentration in nitrogen gas at the time of pulverization to 50 ppm or less, the oxygen amount of the sintered magnet finally obtained was made to be about 0.1 mass%. The particle size D 50 is a value obtained by laser diffraction method using air flow dispersion method (volume-based median diameter).
To the finely pulverized powder, TiH 2 powder having a particle diameter D 50 of 10 μm or less is added in the range of 0 to 0.21 mass%, and zinc stearate as a lubricant is further added to 0 mass per 100 mass% of finely pulverized powder. After adding and mixing .05 mass%, it shape | molded in the magnetic field and obtained the molded object. As a forming apparatus, a so-called perpendicular magnetic field forming apparatus (transverse magnetic field forming apparatus) in which the magnetic field application direction and the pressing direction are orthogonal to each other was used.
The resulting compact is held and sintered in vacuum for 10 hours at 1030 ° C. or more and 1050 ° C. or less (select the temperature at which densification by sintering sufficiently occurs for each sample) and sinter RTB-based sintering I got a magnet. The densities of the RTB-based sintered magnets were all at least 7.5 Mg / m 3 . The sintered R-T-B based sintered magnet is maintained at 900 ° C. in vacuum for 2 hours and then cooled to room temperature, and then kept in vacuum at 500 ° C. for 2 hours and then cooled to room temperature. gave. The analysis results of the components of the obtained RTB-based sintered magnet are shown in Table 1. In addition, Fe, Nd, Pr, Dy, B, Co, Al, Cu, Ga and Ti in Table 1 were measured using high frequency inductively coupled plasma emission spectrometry (ICP-OES). In addition, O (oxygen content), gas melting-infrared absorption method, N (nitrogen content), gas melting-heat conduction method, C (carbon content), using a gas analyzer by combustion-infrared absorption method Measured. Further, in Table 1, TRE is a value obtained by adding up all the amounts of R (Nd, Pr, Dy) (the same applies hereinafter).

Figure 0006541038
Figure 0006541038

熱処理後の焼結磁石に機械加工を施し、縦7mm、横7mm、厚み7mmの試料を作製し、3.2MA/mのパルス磁界で着磁した後、B−Hトレーサによって各試料の磁気特性を測定した。測定結果を表2に示す。なおHはJ(磁化の大きさ)−H(磁界の強さ)曲線の第2象限において、Jが0.9×J(Jは残留磁化、J=B)の値になる位置のHの値(以下同様)である。 The sintered magnet after heat treatment is machined to prepare a sample of 7 mm long, 7 mm wide and 7 mm thick, magnetized with a pulse magnetic field of 3.2 MA / m, and then magnetic properties of each sample by B-H tracer. Was measured. The measurement results are shown in Table 2. Note that H k is a value of 0.9 × J r (J r is residual magnetization, J r = B r ) in the second quadrant of the J (magnitude of magnetization) -H (intensity of magnetic field) curve. Value of H (see below).

Figure 0006541038
Figure 0006541038

表2の試料No.1、2はTi添加の効果を示す実験例である。表2に示すように、
試料No.1、2はいずれも1600kA/mを超える高いHcJが得られたが、B量が少なく、Tiを添加していない試料No.1は、H/HcJが低い。これに対し、本発明の実施形態である試料No.2は高いH及びH/HcJが得られている。
Sample No. in Table 2 1 and 2 are experimental examples showing the effect of Ti addition. As shown in Table 2,
Sample No. Samples No. 1 and No. 2 each obtained high H cJ exceeding 1600 kA / m, but the amount of B was small and sample No. 1 in which Ti was not added. 1 has a low H k / H cJ . On the other hand, sample No. 1 which is an embodiment of the present invention. 2 gives high H k and H k / H cJ .

表2の試料No.2〜6はTi量の限定理由の根拠を示す実験例である。図1に試料No.2〜6におけるTi量とHcJの関係をグラフにしたものを、図2に試料No.2〜6におけるTi量とBの関係をグラフにしたものをそれぞれ示す。図1、2において黒塗りのプロットは実施例(本開示の実施形態)、白抜きのプロットは比較例をそれぞれ表しており、グラフ内の数字は試料No.を表している(以下同様)。試料No.2、4のように、Ti量が本発明の範囲内(0.05質量%以上、0.13質量%以下)にあるとき1600kA/mを超える高いHcJが得られ、さらに高いH及びH/HcJも得られた。一方、試料No.3のようにTiが0.05質量%未満であると、HcJが低下した。また、試料No.5のようにTiが0.13質量%を超えると、HcJは1600kA/mを超える高い水準であったが、Bが大きく低下した。さらに、試料No.6のようにTi量が0.13質量%を大きく超えると、HcJ及びBがともに低下した。 Sample No. in Table 2 2 to 6 are experimental examples showing the basis of the limitation reason of the amount of Ti. In FIG. A graph of the relationship between the Ti content and H cJ in 2 to 6 is shown in FIG. The thing which made the graph the relation of the amount of Ti in 2-6, and B r is shown, respectively. The solid plots in FIGS. 1 and 2 represent the example (the embodiment of the present disclosure), and the white plots represent the comparative examples. (The same applies to the following). Sample No. As in 2 and 4, when the amount of Ti is within the range of the present invention (0.05% by mass or more and 0.13% by mass or less), high H cJ exceeding 1600 kA / m is obtained, and further higher H k and H k / H cJ was also obtained. On the other hand, for sample no. H cJ decreased when Ti was less than 0.05% by mass as in No. 3 . Also, for sample no. When Ti is more than 0.13 mass% as 5, H cJ but was a high level of more than 1600kA / m, B r is decreased significantly. Furthermore, sample no. When the amount of Ti as 6 greatly exceeds 0.13 mass%, H cJ and B r are both reduced.

表2の試料No.2及び試料No.7〜9はB量の限定理由の根拠を示す実験例である。図3、図4に試料No.2及び試料No.7〜9におけるB量とHcJ及びB量とH/HcJの関係をグラフにしたものをそれぞれ示す。試料No.2、8のように、B量が本発明の範囲内(0.88質量%以上、0.92質量%以下)にあるとき1600kA/mを超える高いHcJが得られ、さらに高いH/HcJも得られた。一方、試料No.7のようにBが0.88質量%未満であると、H/HcJが低下した。また、試料No.9のようにBが0.92質量%を超えると、HcJが低下した。 Sample No. in Table 2 2 and sample no. 7-9 are experimental examples which show the grounds of the reason for limitation of B amount. Sample Nos. 3 and 4 are shown in FIGS. 2 and sample no. The graph of the relationship between the amounts of B and H cJ and the amounts of B and H k / H cJ in 7 to 9 is shown. Sample No. As in 2 and 8, when the B content is within the range of the present invention (0.88 mass% or more, 0.92 mass% or less), high H cJ exceeding 1600 kA / m can be obtained, and even higher H k / H cJ was also obtained. On the other hand, for sample no. H k / H cJ decreased when B was less than 0.88% by mass as in No. 7 . Also, for sample no. HcJ decreased when B exceeded 0.92% by mass as in No. 9 .

表2のNo.2及び試料No.10、11はR量の限定理由の根拠を示す実験例である。図5に試料No.2及び試料No.10、11におけるTRE量(すべてのR量の合計)とHcJの関係をグラフにしたものを示す。試料No.11のように、TRE量が本発明の範囲内(32.0質量%以上、34.0質量%以下)にあるとき1600kA/mを超える高いHcJが得られ、さらに高いH及びH/HcJも得られた。さらに、試料No.2のようにTRE量が33.0質量%以上、34.0質量%以下の範囲内にあるとき1700kA/mとさらに高いHcJが得られた。そのため、より高いHcJを得るためには、TRE量が33.0質量%以上、34.0質量%以下であることが好ましい。一方、試料No.10のようにRが32.0質量%未満であると、HcJが低下した。 Table 2 No. 2 and sample no. 10 and 11 are experiment examples which show the ground of the reason for limitation of R amount. In FIG. 2 and sample no. The graph of the relationship between the TRE amount (total of all R amounts) and H cJ at 10 and 11 is shown. Sample No. As in 11, when the TRE content is within the range of the present invention (32.0 mass% or more, 34.0 mass% or less), high H cJ exceeding 1600 kA / m is obtained, and further higher H k and H k / H cJ was also obtained. Furthermore, sample no. 2 as TRE weight 33.0% by mass or more, even higher H cJ and 1700kA / m when in the range of 34.0 mass% or less was obtained. Therefore, in order to obtain higher HcJ , the TRE amount is preferably 33.0% by mass or more and 34.0% by mass or less. On the other hand, for sample no. H cJ decreased when R was less than 32.0% by mass as in No. 10 .

表2の試料No.2及び試料No.12〜14はGa量の限定理由の根拠を示す実験例である。図6に試料No.2及び試料No.12〜14におけるGa量とHcJの関係をグラフにしたものを示す。試料No.13のように、Ga量が本発明の範囲内(0.60質量%以上、1.10質量%以下)にあるとき1600kA/mを超える高いHcJが得られ、さらに高いH及びH/HcJも得られた。さらに試料No.2、14のようにGa量が0.70質量%超1.10質量%以下の範囲内にあるとき1700kA/m以上のさらに高いHcJが得られた。そのため、より高いHcJを得るためには、Ga量が0.70質量%超1.10質量%以下であることが好ましい。一方、試料No.12のようにGaが0.60質量%未満であると、HcJが低下した。 Sample No. in Table 2 2 and sample no. 12-14 is an experimental example which shows the grounds of the reason of limitation of the amount of Ga. In FIG. 2 and sample no. The thing which made the graph the relation of the amount of Ga and HcJ in 12-14 is shown. Sample No. As in 13, when the amount of Ga is within the range of the present invention (0.60 mass% or more, 1.10 mass% or less), high H cJ exceeding 1600 kA / m can be obtained, and further higher H k and H k / H cJ was also obtained. Furthermore, sample no. When the amount of Ga is in the range of more than 0.70% by mass and 1.10% by mass or less as in Nos. 2 and 14, a further higher HcJ of 1700 kA / m or more was obtained. Therefore, in order to obtain higher HcJ , the amount of Ga is preferably more than 0.70% by mass and 1.10% by mass or less. On the other hand, for sample no. When the Ga content was less than 0.60% by mass as in Example 12 , the H cJ decreased.

表2の試料No.2及び試料No.15、16はCu量の限定理由の根拠を示す実験例である。図7に試料No.2及び試料No.15、16におけるCu量とHcJの関係をグラフにしたものを示す。試料No.2、16のように、Cu量が本発明の範囲内(0.20質量%以上、0.35質量%以下)にあるとき1600kA/mを超える高いHcJが得られ、さらに高いH及びH/HcJも得られた。一方、試料No.15のようにCuが0.20質量%未満であると、HcJが低下した。 Sample No. in Table 2 2 and sample no. 15, 16 are experimental examples showing the basis of the reason for limitation of the amount of Cu. In FIG. 2 and sample no. The thing which made the amount of Cu in 15, 16 and the relationship of HcJ graphed is shown. Sample No. As in 2 and 16, when the amount of Cu is within the range of the present invention (0.20% by mass or more and 0.35% by mass or less), high H cJ exceeding 1600 kA / m is obtained, further higher H k and H k / H cJ was also obtained. On the other hand, for sample no. When Cu was less than 0.20% by mass as in No. 15, H cJ decreased.

<実験例2>
電解鉄、Ndメタル、Prメタル、Dyメタル、フェロボロン合金、電解Co、Alメタル、Cuメタル、Gaメタル及びTiメタルを用いて(メタルはいずれも純度99%以上)、表3の試料No.17〜22に示すR−T−B系焼結磁石の組成となるように配合し、それらの原料を溶解してストリップキャスト法により鋳造し、厚み0.2mm以上、0.4mm以下のフレーク状の原料合金を得た。得られたフレーク状の原料合金を水素加圧雰囲気で水素脆化させた後、550℃まで真空中で加熱、冷却する脱水素処理を施し、粗粉砕粉を得た。次に、得られた粗粉砕粉に、潤滑剤としてステアリン酸亜鉛を粗粉砕粉100質量%に対して0.035質量%添加、混合した後、気流式粉砕機(ジェットミル装置)を用いて、窒素流気中で乾式粉砕し、粒径D50が4μmの微粉砕粉(合金粉末)を得た。なお、本実験例では、粉砕時の窒素ガス中の酸素濃度を50ppm以下とすることにより、最終的に得られる焼結磁石の酸素量が0.1質量%前後となるようにした。
前記微粉砕粉に、潤滑剤としてステアリン酸亜鉛を微粉砕粉100質量%に対して0.05質量%添加、混合した後、磁界中で成形し、成形体を得た。なお、成形装置には直角磁界成形装置を用いた。得られた成形体を、真空中で1080℃以上、1100℃以下(試料ごとに焼結による緻密化が十分起こる温度を選定)で4時間保持して焼結し、R−T−B系焼結磁石を得た。R−T−B系焼結磁石の密度はいずれも7.5Mg/m以上であった。焼結後のR−T−B系焼結磁石に、実験例1と同様の熱処理を行った。得られたR−T−B系焼結磁石の組成を実験例1と同様な方法により測定した。測定結果を表3に示す。
<Experimental Example 2>
Using electrolytic iron, Nd metal, Pr metal, Dy metal, ferroboron alloy, electrolytic Co, Al metal, Cu metal, Ga metal and Ti metal (all metals have a purity of 99% or more). It mixes so that it may become the composition of the RTB-based sintered magnet shown to 17-22, melts those raw materials, casts it by the strip casting method, and is flake shape 0.2mm-0.4mm in thickness The raw material alloy was obtained. The obtained flake-like raw material alloy was subjected to hydrogen embrittlement in a hydrogen pressurized atmosphere, and then subjected to dehydrogenation treatment of heating and cooling in vacuum to 550 ° C. to obtain roughly crushed powder. Next, to the obtained coarsely pulverized powder, 0.035% by mass of zinc stearate as a lubricant is added with respect to 100% by mass of the coarsely pulverized powder and mixed, and then using an air flow crusher (jet mill apparatus) was dry milled in a nitrogen Nagareki, the particle size D 50 was obtained finely pulverized powder of 4μm (the alloy powder). In the present experimental example, by setting the oxygen concentration in nitrogen gas at the time of pulverization to 50 ppm or less, the oxygen amount of the sintered magnet finally obtained was made to be about 0.1 mass%.
After adding and mixing 0.05 mass% of zinc stearate as a lubricant with respect to 100% by mass of the finely pulverized powder to the finely pulverized powder, the mixture is molded in a magnetic field to obtain a molded body. In addition, the rectangular magnetic field molding apparatus was used for the molding apparatus. The resulting compact is held and sintered for 4 hours in a vacuum at 1080 ° C. or more and 1100 ° C. or less (the temperature at which sufficient densification due to sintering is sufficiently selected for each sample) to sinter the R-T-B system I got a magnet. The densities of the RTB-based sintered magnets were all at least 7.5 Mg / m 3 . The same heat treatment as in Experimental Example 1 was performed on the sintered RTB-based sintered magnet. The composition of the resulting RTB-based sintered magnet was measured in the same manner as in Experimental Example 1. The measurement results are shown in Table 3.

Figure 0006541038
Figure 0006541038

熱処理後の焼結磁石を実験例1と同様な方法で加工した後、実験例1と同様な方法により測定し、磁気特性を求めた。その結果を表4に示す。   After processing the sintered magnet after the heat treatment in the same manner as in Experimental Example 1, the magnetic characteristics were determined by measuring in the same manner as in Experimental Example 1. The results are shown in Table 4.

Figure 0006541038
Figure 0006541038

表4の試料No.17〜20は本発明の式(1)及び式(2)による組成限定の理由を示す実験例である。図8に試料No.17〜20におけるn/nBeffとHcJの関係をグラフにしたものを示す。尚、n/nBeff=[(Fewt/Feat)+(Cowt/Coat)+(Alwt/Alat)]/[(Bwt/Bat)−2×(Tiwt/Tiat)]である。
磁石組成が式(1)を満たしている試料No.18〜20はいずれも1600kA/mを超える高いHcJが得られ、さらに高いH及びH/HcJも得られた。さらに、試料No.20のように、磁石組成が式(1)及び式(2)を満たしているものは、HcJが1700kA/m以上のさらに高いH及びH/HcJが得られた。そのため、より高いHcJを得るためには、式(1)及び式(2)を満たすことが好ましい。一方、試料No.17のように磁石組成が式(1)を満たさなかったものは、HcJが低下した。
The sample numbers in Table 4 17 to 20 are experimental examples showing the reasons for limitation of the composition according to the formulas (1) and (2) of the present invention. In FIG. Indicating those graphed the relationship between the n T / n Beff and H cJ at 17-20. Note that n T / n B eff = [(Fe wt / Fe at ) + (Co wt / Co at ) + (Al wt / Al at )] / [(B wt / B at ) -2 × (Ti wt / Ti) at )].
Sample No. 1 in which the magnet composition satisfies the formula (1). 18-20 are all high H cJ exceeding 1600 kA / m, which was also obtained higher H k and H k / H cJ. Furthermore, sample no. As in No. 20, in the cases where the magnet composition satisfies the expressions (1) and (2), higher H k and H k / H cJ with H cJ of 1700 kA / m or more were obtained. Therefore, in order to obtain higher H cJ , it is preferable to satisfy Formula (1) and Formula (2). On the other hand, for sample no. In the case where the magnet composition did not satisfy Formula (1) as in No. 17, H cJ decreased.

表4の試料No.21、22はRの種類が異なる実験例である。試料No.21のように、RにPrが含まれない場合であっても、1600kA/mを超える高いHcJが得られ、さらに高いH及びH/HcJも得られた。また、試料No.22のように、RにDyが含まれる場合、Dy含有量に見合った高いHcJを得ることができ、高いH及びH/HcJも得られた。 The sample numbers in Table 4 21 and 22 are experimental examples in which the type of R is different. Sample No. As in 21, even when R does not contain Pr, high H cJ higher than 1600 kA / m was obtained, and even higher H k and H k / H cJ were also obtained. Also, for sample no. As in 22, when R contains Dy, high H cJ commensurate with the Dy content can be obtained, and high H k and H k / H cJ are also obtained.

Claims (6)

R(RはR1とR2とからなり、R1はDy、Tb、Gd及びHoを除く希土類元素のうち少なくとも一種でありNd及び/又はPrを必ず含む、R2はDy、Tb、Gd及びHoの少なくとも一種であり、R−T−B系焼結磁石全体の1.5質量%以下である):32.0質量%以上、34.0質量%以下、
B:0.88質量%以上、0.92質量%以下、
Ga:0.60質量%以上、1.10質量%以下、
Cu:0.20質量%以上、0.35質量%以下、
Ti:0.05質量%以上、0.13質量%以下、
Al:0.05質量%以上、0.50質量%以下、
を含有し、残部T(TはFe又はFeとCo)及び不可避的不純物からなり、且つ、下記式(1)を満足する組成を有するR−T−B系焼結磁石。
14.4≦[(Fewt/Feat)+(Cowt/Coat)+(Alwt/Alat)]/[(Bwt/Bat)−2×(Tiwt/Tiat)]≦15.4 (1)
(FewtはFeの質量%の値であり、FeatはFeの原子量の値であり、CowtはCoの質量%の値であり、CoatはCoの原子量の値であり、AlwtはAlの質量%の値であり、AlatはAlの原子量の値であり、BwtはBの質量%の値であり、BatはBの原子量の値であり、TiwtはTiの質量%の値であり、TiatはTiの原子量の値である)
R (R is composed of R 1 and R 2, R 1 is at least one of rare earth elements other than Dy, Tb, Gd and Ho and necessarily includes Nd and / or Pr; R 2 is at least Dy, Tb, Gd and Ho It is one kind and is 1.5 mass% or less of the whole RTB based sintered magnet): 32.0 mass% or more, 34.0 mass% or less,
B: 0.88 mass% or more, 0.92 mass% or less,
Ga: 0.60 mass% or more, 1.10 mass% or less,
Cu: 0.20 mass% or more, 0.35 mass% or less,
Ti: 0.05% by mass or more and 0.13% by mass or less,
Al: 0.05% by mass or more, 0.50% by mass or less,
An RTB-based sintered magnet comprising: a balance T (T: Fe or Fe and Co) and unavoidable impurities; and a composition satisfying the following formula (1).
14.4 ≦ [(Fe wt / Fe at ) + (Co wt / Co at ) + (Al wt / Al at )] / [(B wt / B at ) −2 × (Ti wt / Ti at )] ≦ 15.4 (1)
(Fe wt is a value of mass% of Fe, Fe at is a value of atomic weight of Fe, Co wt is a value of mass% of Co, Co at is a value of atomic weight of Co, Al wt is It is a value of mass% of Al, Al at is a value of atomic weight of Al, B wt is a value of mass% of B, B at is a value of atomic weight of B, and Ti wt is a mass% of Ti Where Ti at is the atomic weight value of Ti)
R:33.0質量%以上、34.0質量%以下である請求項1に記載のR−T−B系焼結磁石。   R: 33.0 mass% or more and 34.0 mass% or less 3. The RTB-based sintered magnet according to claim 1. Ga:0.70質量%超、1.10質量%以下である請求項1又は2に記載のR−T−B系焼結磁石。   The RTB-based sintered magnet according to claim 1 or 2, wherein Ga is more than 0.70% by mass and 1.10% by mass or less. 前記組成がさらに下記式(2)を満足する、請求項1から3のいずれかに記載のR−T−B系焼結磁石。
14.8≦[(Fewt/Feat)+(Cowt/Coat)+(Alwt/Alat)]/[(Bwt/Bat)−2×(Tiwt/Tiat)]≦15.4 (2)
The R-T-B-based sintered magnet according to any one of claims 1 to 3, wherein the composition further satisfies the following formula (2).
14.8 ≦ [(Fe wt / Fe at ) + (Co wt / Co at ) + (Al wt / Al at )] / [(B wt / B at ) −2 × (Ti wt / Ti at )] ≦ 15.4 (2)
前記Rは、Dy、Tb、Gd及びHoをいずれも含有しない、請求項1から4のいずれかに記載のR−T−B系焼結磁石。   The RTB-based sintered magnet according to any one of claims 1 to 4, wherein said R does not contain any of Dy, Tb, Gd and Ho. 前記R−T−B系焼結磁石の酸素量が0.2質量%以下である、請求項1から5のいずれかに記載のR−T−B系焼結磁石。   The RTB-based sintered magnet according to any one of claims 1 to 5, wherein the oxygen content of the RTB-based sintered magnet is 0.2 mass% or less.
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