JP2794497B2 - R-Fe-BC permanent magnet alloy with low irreversible demagnetization and excellent thermal stability - Google Patents
R-Fe-BC permanent magnet alloy with low irreversible demagnetization and excellent thermal stabilityInfo
- Publication number
- JP2794497B2 JP2794497B2 JP3048759A JP4875991A JP2794497B2 JP 2794497 B2 JP2794497 B2 JP 2794497B2 JP 3048759 A JP3048759 A JP 3048759A JP 4875991 A JP4875991 A JP 4875991A JP 2794497 B2 JP2794497 B2 JP 2794497B2
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- JP
- Japan
- Prior art keywords
- less
- magnet
- irreversible demagnetization
- grain boundary
- atomic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 230000005347 demagnetization Effects 0.000 title claims description 67
- 230000002427 irreversible effect Effects 0.000 title claims description 66
- 229910045601 alloy Inorganic materials 0.000 title claims description 48
- 239000000956 alloy Substances 0.000 title claims description 48
- 239000013078 crystal Substances 0.000 claims description 37
- 239000000203 mixture Substances 0.000 claims description 26
- 239000012535 impurity Substances 0.000 claims description 17
- 229910052791 calcium Inorganic materials 0.000 claims description 12
- 229910052796 boron Inorganic materials 0.000 claims description 10
- 229910052788 barium Inorganic materials 0.000 claims description 6
- 229910052749 magnesium Inorganic materials 0.000 claims description 6
- 229910052691 Erbium Inorganic materials 0.000 claims description 5
- 229910052779 Neodymium Inorganic materials 0.000 claims description 5
- 229910052771 Terbium Inorganic materials 0.000 claims description 5
- 229910052775 Thulium Inorganic materials 0.000 claims description 5
- 229910052790 beryllium Inorganic materials 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 229910052712 strontium Inorganic materials 0.000 claims description 5
- 229910052684 Cerium Inorganic materials 0.000 claims description 4
- 229910052689 Holmium Inorganic materials 0.000 claims description 4
- 229910052777 Praseodymium Inorganic materials 0.000 claims description 4
- 229910052772 Samarium Inorganic materials 0.000 claims description 4
- 229910052769 Ytterbium Inorganic materials 0.000 claims description 4
- 229910052744 lithium Inorganic materials 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- 229910052727 yttrium Inorganic materials 0.000 claims description 4
- 229910052688 Gadolinium Inorganic materials 0.000 claims description 3
- 229910052746 lanthanum Inorganic materials 0.000 claims description 3
- -1 D y Inorganic materials 0.000 claims description 2
- 230000000052 comparative effect Effects 0.000 description 22
- 238000000034 method Methods 0.000 description 19
- 239000000463 material Substances 0.000 description 18
- 230000000694 effects Effects 0.000 description 16
- 230000003647 oxidation Effects 0.000 description 16
- 238000007254 oxidation reaction Methods 0.000 description 16
- 230000006872 improvement Effects 0.000 description 14
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 13
- 239000011575 calcium Substances 0.000 description 11
- 230000007423 decrease Effects 0.000 description 11
- 239000002994 raw material Substances 0.000 description 10
- 230000002829 reductive effect Effects 0.000 description 10
- 230000004907 flux Effects 0.000 description 9
- 230000002441 reversible effect Effects 0.000 description 9
- 229910052799 carbon Inorganic materials 0.000 description 8
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 7
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 7
- 239000000843 powder Substances 0.000 description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 230000006866 deterioration Effects 0.000 description 6
- 230000007613 environmental effect Effects 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000011253 protective coating Substances 0.000 description 6
- 229910052761 rare earth metal Inorganic materials 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 239000000654 additive Substances 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 230000000996 additive effect Effects 0.000 description 4
- 238000005275 alloying Methods 0.000 description 4
- 239000006229 carbon black Substances 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 4
- 230000007547 defect Effects 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000000265 homogenisation Methods 0.000 description 4
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 4
- 230000005381 magnetic domain Effects 0.000 description 4
- 229910052692 Dysprosium Inorganic materials 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 3
- 238000005266 casting Methods 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 230000005415 magnetization Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910020674 Co—B Inorganic materials 0.000 description 2
- 229910017086 Fe-M Inorganic materials 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000004453 electron probe microanalysis Methods 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 229910001004 magnetic alloy Inorganic materials 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 229910000521 B alloy Inorganic materials 0.000 description 1
- 229910017112 Fe—C Inorganic materials 0.000 description 1
- 229910001047 Hard ferrite Inorganic materials 0.000 description 1
- 229910001122 Mischmetal Inorganic materials 0.000 description 1
- 235000014676 Phragmites communis Nutrition 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002999 depolarising effect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 229910001068 laves phase Inorganic materials 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- 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
- H01F1/058—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IVa elements, e.g. Gd2Fe14C
Description
【０００１】[0001]
【産業上の利用分野】本発明は，不可逆減磁の小さい熱
安定性の優れたＲ（希土類元素)-Ｆe-Ｂ-Ｃ系の永久磁
石合金に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an R (rare earth element) -Fe-BC permanent magnet alloy having small irreversible demagnetization and excellent thermal stability.
【０００２】[0002]
【従来の技術】近年, Ｓm-Ｃo系磁石の磁力を凌ぐ次世
代の永久磁石としてＲ-Ｆe-Ｂ系磁石が佐川等によって
発表されて以来, 当該磁石について多くの報告がなされ
てきた。しかしながら，該磁石はＳm-Ｃo系磁石に比べ
て磁力は優れるものの, その磁気特性の熱安定性及び耐
酸化性が著しく劣るという欠点を有する。特に耐酸化性
に係わる欠点は，重要な改善課題であり, 上述報告の多
くはその改善方法を開示している。2. Description of the Related Art In recent years, since an R-Fe-B magnet was announced by Sagawa et al. As a next-generation permanent magnet exceeding the magnetic force of a Sm-Co magnet, many reports have been made on the magnet. However, although this magnet is superior in magnetic force to Sm-Co-based magnets, it has the drawback that the thermal stability and oxidation resistance of its magnetic properties are extremely poor. The disadvantage of oxidation resistance in particular is an important improvement task, and many of the above reports disclose methods for improvement.
【０００３】他方，従来のＲ-Ｆe-Ｂ又はＲ-Ｆe-Ｃo-Ｂ
系磁石は環境温度が上昇すると残留磁束密度 (Ｂr)およ
び保磁力(iHc)がＳm-Ｃo系磁石に比較して著しく低下す
るという性質がある。すなわち熱安定性に劣るという欠
点がある。このような状況下，環境温度の変化に対して
磁気特性の安定化を図る手段としては，一般に残留磁束
密度の温度依存係数を小さくすること及び室温における
保磁力を十分に高くすることが提案されている。前者の
改善法としては，磁石のキューリー温度を高める方法が
一般的であり, 例えば特開昭59-64733号公報では，Ｆe
の一部をＣoで置換することによりキューリー温度を高
め, 残留磁束密度の温度依存係数を小さくすることを提
案している。他方, 環境温度の上昇に伴って, 保磁力が
急激に低下することは既に述べたところだが, この保磁
力の低下がもたらす重大な欠点は, 大きな不可逆減磁を
招くということである。On the other hand, conventional R-Fe-B or R-Fe-Co-B
The system magnet has a property that the residual magnetic flux density (Br) and the coercive force (iHc) are significantly reduced as the environmental temperature is increased, as compared with the Sm-Co system magnet. That is, there is a disadvantage that thermal stability is poor. Under these circumstances, as a means to stabilize magnetic properties against changes in environmental temperature, it has been generally proposed to reduce the temperature dependence coefficient of the residual magnetic flux density and sufficiently increase the coercive force at room temperature. ing. As the former improvement method, a method of increasing the Curie temperature of the magnet is generally used. For example, Japanese Patent Application Laid-Open No. 59-64733 discloses Fe
It has been proposed to increase the Curie temperature and reduce the temperature dependence of the residual magnetic flux density by replacing a part of Co with Co. On the other hand, it has already been mentioned that the coercive force decreases sharply with increasing environmental temperature. However, a serious disadvantage of this decrease in coercive force is that it causes large irreversible demagnetization.
【０００４】不可逆減磁とは，高温時低下したＢrが室
温に戻した時に元に回復しない現象であり，一般に磁石
形状の薄型化に伴ってその劣化が顕著になる。この不可
逆減磁の劣化は, たとえＦeの一部をＣoで置換して残留
磁束密度の温度依存係数を小さくしても, 抜本的な改善
には至らない。このため，実使用に際しては環境温度及
び形状が厳しく制限され, 例えば自動車関係, 高速機器
等の過酷な用途への適用は困難となる。この不可逆減磁
の改善法としては専ら室温におけるiHcを高める方法に
頼っているのが実状である。つまり，高温時のiHcの低
下を見込んで, 室温でのiHcを十分に高くすることによ
って不可逆減磁を小さくする方法であるが, 例えば特開
昭59-89401号公報は，Ｔi,Ｎi,Ｂi,Ｖ,Ｎb,Ｃr,Ｍo等を
添加することにより, 室温におけるiHcを高め, 不可逆
減磁率を小さくすることを教示し，又，特開昭60-32306
号公報は，希土類元素成分として, 軽希土類元素に加
え, Ｄy,Ｔb,Ｈo,Ｇd,Ｅr,Ｔm,Ｙbの重希土類元素の添
加を特定し，これによりiHcを高め, 不可逆減磁率を改
善することを教示している。[0004] Irreversible demagnetization is a phenomenon in which Br that has decreased at high temperatures does not recover when it returns to room temperature. In general, the deterioration becomes remarkable as the magnet shape becomes thinner. This deterioration of the irreversible demagnetization does not lead to a drastic improvement even if a part of Fe is replaced with Co to reduce the temperature dependence coefficient of the residual magnetic flux density. For this reason, in actual use, the environmental temperature and shape are severely restricted, and it is difficult to apply to severe applications such as automobile-related and high-speed equipment. As a method of improving the irreversible demagnetization, the actual situation relies exclusively on a method of increasing iHc at room temperature. In other words, a method of reducing the irreversible demagnetization by sufficiently increasing the iHc at room temperature in anticipation of the decrease in iHc at high temperatures is known. For example, JP-A-59-89401 discloses Ti, Ni, Bi. , V, Nb, Cr, Mo, etc. are taught to increase iHc at room temperature and reduce the irreversible demagnetization rate.
Japanese Patent Application Publication No. JP-A-2005-26095 specifies the addition of heavy rare earth elements such as Dy, Tb, Ho, Gd, Er, Tm, and Yb as rare earth elements in addition to light rare earth elements, thereby increasing iHc and improving irreversible demagnetization rate. Teaching that.
【０００５】しかし，このようにしてiHcを十分高めれ
ば確かに不可逆減磁は改善されるものの, 従来法では例
えば160℃の高温にもなると, たとえ室温時のiHcが15〜
20kOeと十分高くても急激に劣化すると言う問題点が残
る。この場合, 更にiHcを高くすることになる。一方，
このようにiHcが高くなると，着磁の問題が新たに発生
する。即ち, 磁石の磁力を最大に引き出すためにはその
磁力が飽和するまで十分大きな磁界で着磁する必要があ
り，着磁率が低いと磁気特性の不安定を招くが，通常，
該着磁界の大きさとしては磁石が有するiHcの３〜４倍
の磁界が必要とされることから，従来法のように極端な
iHcの増加は，着・脱磁の操作を困難にし，又, 設備の
大型化を招くことになる。したがって，従来においては
上記高温時の不可逆減磁の劣化と共にこれらの問題を避
けることはできなかった。However, although the irreversible demagnetization can be improved if the iHc is sufficiently increased in this way, the conventional method, for example, when the temperature is as high as 160 ° C., the iHc at room temperature becomes 15 to
Even if it is sufficiently high as 20 kOe, there still remains a problem that it rapidly deteriorates. In this case, iHc is further increased. on the other hand,
When the iHc is increased in this way, a new problem of magnetization occurs. That is, in order to extract the magnetic force of the magnet to the maximum, it is necessary to magnetize it with a sufficiently large magnetic field until the magnetic force saturates. If the magnetizability is low, the magnetic characteristics become unstable.
The magnitude of the applied magnetic field is required to be 3 to 4 times the magnetic field of iHc of the magnet.
The increase in iHc makes it difficult to operate the attachment and demagnetization and causes the equipment to become larger. Therefore, conventionally, these problems cannot be avoided together with the deterioration of the irreversible demagnetization at the high temperature.
【０００６】[0006]
【発明が解決しようとする課題】このように, 従来のＲ
-Ｆe-Ｂ系磁石では，高い環境温度での不可逆減磁に対
して, 十分な改善効果を得るに至っておらず，Ｓm-Ｃo
系に比べて優れた磁力を有するにも拘らず, 特に高温時
の熱安定性及び実用レベルでの高iHc化に伴う着磁の問
題が, 依然として存在し，上記メリットが大きく損なわ
れているのが実状である。As described above, the conventional R
-Fe-B magnets have not yet achieved a sufficient improvement effect on irreversible demagnetization at high environmental temperatures.
Despite the superior magnetic force compared to the system, the problems of thermal stability, especially at high temperatures, and magnetization due to high iHc at practical levels still exist, and the above advantages are greatly impaired. Is the actual situation.
【０００７】一般に, Ｒ-Ｆe-Ｂ (またはＲ-Ｆe-Ｃo-
Ｂ) 系磁石は, Ｒ2Ｆe14Ｂ〔またはＲ2(Ｆe,Ｃo)14Ｂ〕
型の正方晶と，ＲＦe4Ｂ4〔Ｒ(Ｆe,Ｃo)4Ｂ4〕型のＢリ
ッチ相, Ｒリッチ相及びＢ2Ｏ3相を含む非磁性相とから
構成され (尚, Ｒ-Ｆe-Ｃo-Ｂ系磁石ではＲ(Ｆe,Ｃo)2
で代表されるラーベス相も存在するとされている),その
保磁力発生の原理は，逆磁区核発生機構によるとされて
いる。つまり, この逆磁区の存在が保磁力を決定し，そ
の成長に伴いiHcが低下することから，核発生型磁石の
保磁力は構造敏感型となり正方晶と粒界相, Ｒリッチ
相, Ｂリッチ相及びその他不純物相に支配されることに
なる。Generally, R-Fe-B (or R-Fe-Co-
B) The system magnet is R 2 Fe 14 B [or R 2 (Fe, Co) 14 B]
And a nonmagnetic phase including a B-rich phase, an R-rich phase, and a B 2 O 3 phase of the RFe 4 B 4 [R (Fe, Co) 4 B 4 ] type. R (Fe, Co) 2 for Fe-Co-B magnet
It is said that there is also a Laves phase represented by), and the principle of the coercive force generation is based on the reverse domain nucleation mechanism. In other words, the existence of the reverse magnetic domain determines the coercive force, and iHc decreases with its growth. Therefore, the coercive force of the nucleation-type magnet becomes a structure-sensitive type, and the tetragonal crystal, grain boundary phase, R-rich phase, and B-rich Phase and other impurity phases.
【０００８】ところで，該逆磁区核の芽, 即ち逆磁区核
は正方晶及び粒界相の欠陥, 軟質な磁性相, その他不純
物相において発生し，これらの欠陥, 異物の存在により
容易に成長する。このように, 磁石の組織が不均質であ
ったり不純物及び種々の欠陥を含むと, iHcは容易に低
下し，これに伴い実用レベルで重要となる残留磁気の不
可逆減磁は大きくなる。The buds of the reverse domain nuclei, that is, the reverse domain nuclei, are generated in defects of the tetragonal and grain boundary phases, soft magnetic phases, and other impurity phases, and easily grow due to the presence of these defects and foreign substances. . As described above, when the structure of the magnet is inhomogeneous or includes impurities and various defects, iHc is easily reduced, and the irreversible demagnetization of remanence, which is important on a practical level, is accordingly increased.
【０００９】以上のことから，不可逆減磁率を小さくす
る基本的な対策としては，磁石組織の観点から次のこと
が言える。(1) 正方晶の均質化,(2) 粒界相の均質・均
一化, (3) 軟質な磁性相の除去, (4) その他不純物相の
除去，である。これらの改善がなされた後に，iHcを適
正化することにより抜本的な不可逆減磁の改善に至ると
考えられる。From the above, as a basic measure for reducing the irreversible demagnetization rate, the following can be said from the viewpoint of the magnet structure. (1) homogenization of tetragonal crystals, (2) homogenization and homogenization of grain boundary phase, (3) removal of soft magnetic phase, and (4) removal of other impurity phases. After these improvements are made, it is thought that optimization of iHc will lead to drastic improvement of irreversible demagnetization.
【００１０】なお，従来の不可逆減磁の改善法として例
えば前出の特開昭59-89401号公報及び特開昭60-32306号
公報は，室温におけるiHcを十分高めることにより改善
する方法を開示していることを既に述べたが，これらの
方法では磁石の組織に対しては何ら改善がなされておら
ず, 単に添加物により異方性磁界を大きくすることによ
って, 室温におけるiHcを極めて高くし，その結果, 不
可逆減磁を改善するという, 高温時のiHcの低下を犠牲
にした消極的な改善方法である。このため，より高温時
の改善効果は少なく, 又着磁等の問題が残ることは，既
に既述した。As conventional methods for improving irreversible demagnetization, for example, the above-mentioned Japanese Patent Application Laid-Open Nos. 59-89401 and 60-32306 disclose a method of improving the iHc at room temperature by sufficiently increasing it. As mentioned above, these methods have not improved the structure of the magnet at all, and the iHc at room temperature can be extremely increased simply by increasing the anisotropic magnetic field with additives. This is a passive improvement method that improves irreversible demagnetization at the expense of lowering iHc at high temperatures. As described above, the effect of improvement at higher temperatures is small, and problems such as magnetization remain.
【００１１】一方, 永久磁石合金の組成を均質にし, iH
cを向上させる方法も数多く報告されており, 一般には
磁石合金を熱処理することが提案されている。例えば特
開昭59-217304号公報では，焼結後350℃以上の温度で熱
処理することにより, iHcが改善されることを教示して
いる。該法によれば, 熱処理することにより磁石組成の
均質化は改善されるものの, 依然としてＢリッチ相やＢ
2Ｏ3相等の不純物相が存在していることから, 組織の構
造上は何ら変化がなく逆磁区核の発生点及びその成長に
対しては，抜本的に解決されていない。このため該法に
よりiHcを高めても高温時の不可逆減磁の改善効果は小
さいと判断される。On the other hand, the composition of the permanent magnet alloy
Many methods for improving c have been reported, and it has generally been proposed to heat treat a magnetic alloy. For example, JP-A-59-217304 teaches that heat treatment at 350 ° C. or more after sintering improves iHc. According to this method, although the homogenization of the magnet composition is improved by heat treatment, the B-rich phase and B
Since there is an impurity phase such as the 2 O 3 phase, there is no change in the structure of the structure, and the generation point and the growth of the reverse domain nucleus have not been fundamentally solved. Therefore, even if iHc is increased by this method, the effect of improving irreversible demagnetization at high temperatures is considered to be small.
【００１２】このように従来技術による不可逆減磁の改
善は磁石合金組織の構造に何ら対策手段を講じていない
のが実状である。As described above, it is the actual state that no measures are taken for the improvement of the irreversible demagnetization according to the prior art in the structure of the magnet alloy structure.
【００１３】また，不純物を除去することにより逆磁区
核の発生及びその成長を抑制する方法としては, 例えば
酸化物相並びにＢリッチ相等の生成を抑制することが考
えられ，酸化物については磁石中の酸素を低減すること
により抑制することが可能である。また，Ｂリッチ相に
ついては従来材では多く存在し，その大きさは正方晶と
同程度にもなることから，不純物相としての欠陥だけで
なく, 場合によっては大きな磁気的空間となり減磁界形
成の要因にもなる。しかしながら, 従来より実用レベル
の高い磁気特性を得るためにはＢの含有量を高くせざる
を得ないのが実状であり，例えば特開昭59-46008号公報
及び前摘の特開昭59-64733号公報では, １kOe以上のiHc
を確保するためには，Ｂ含有量を２〜28原子％に特定し
ており,iHcを３kOeにするためには，Ｂ含有量は少なく
とも４原子％必要であるとし，更に実用レベルの高いiH
cを得るためには，Ｂの含有量をさらに高くすることを
教示している。As a method of suppressing the generation and growth of reverse magnetic domain nuclei by removing impurities, for example, it is conceivable to suppress the formation of an oxide phase and a B-rich phase. Can be suppressed by reducing the amount of oxygen. In addition, the B-rich phase is often present in conventional materials, and its size is about the same as that of tetragonal crystals. Therefore, not only defects as impurity phases, but also a large magnetic space, and in some cases, a large magnetic space, It is also a factor. However, in order to obtain magnetic properties of a practically higher level than in the past, it is necessary to increase the B content. For example, Japanese Patent Application Laid-Open No. 59-46008 and Japanese Patent Application Laid-Open No. According to Japanese Patent No. 64733, iHc of 1 kOe or more
The B content is specified to be 2 to 28 atomic% in order to secure the required B content, and the B content is required to be at least 4 atomic% in order to make iHc 3 kOe.
In order to obtain c, it teaches to further increase the B content.
【００１４】即ち，従来技術では，Ｂ含有量を少なくす
るとα-Ｆeが析出しやすくなりこれに伴いiHcは急激に
低下するので，iHcを高めるためにＢ含有量を多くする
という考え方に立っていることから，Ｂリッチ相の生成
を抑制することはできなかった。従ってこのようにＢを
多く含み,不純物相として多くのＢリッチ相を含有する
従来材を実用化するためには，高温時の不可逆減磁対策
として, 前述のごとく極めて高いiHcが必要となる。That is, in the prior art, when the B content is reduced, α-Fe is easily precipitated, and the iHc is rapidly reduced with the precipitation. Therefore, from the viewpoint of increasing the B content in order to increase iHc. Therefore, the formation of the B-rich phase could not be suppressed. Therefore, in order to put such a conventional material containing a large amount of B and containing a large amount of the B-rich phase as an impurity phase into practical use, an extremely high iHc is required as a measure against irreversible demagnetization at a high temperature as described above.
【００１５】本発明の目的はこのようなＲ-Ｆe-Ｂ系永
久磁石の問題, とりわけ, 不可逆減磁の問題点を解決す
ることにあり, 従来材のように, iHcを極めて高くする
ことなく比較的低いiHcでも不可逆減磁が小さく熱安定
性に優れた永久磁石合金を提供することにある。An object of the present invention is to solve such a problem of the R-Fe-B permanent magnet, in particular, the problem of irreversible demagnetization, without increasing iHc as in conventional materials. An object of the present invention is to provide a permanent magnet alloy which has a small irreversible demagnetization even at a relatively low iHc and excellent thermal stability.
【００１６】[0016]
【課題を解決するための手段】本発明者等は，これらの
問題点を解決するための手段として, 磁石合金の組織構
造による抜本的な不可逆減磁の改善を鋭意検討した結
果, 正方晶構造を有する磁性結晶粒及びＲリッチ粒界相
を均質にし, 且つ磁性結晶粒の各々を該粒界相で被覆す
ることにより, 従来材に比べて著しく不可逆減磁が改善
されることを見い出し, 更には, これらの効果を一層高
めるために，Ｂリッチ相を除去するという従来技術で
は，予想すら困難であった新規技術を見出すに至り, 従
来材より低いiHcでも高温に於ける不可逆減磁が極めて
小さく, 且つ同等以上の最大エネルギー積を有する新規
な永久磁石合金の提供を可能とした。即ち, 従来技術で
はもはや高い磁気特性が得られず実用範囲外とされてい
たＢ含有量２原子％未満領域でも実用に耐え得る良好な
磁気特性を付与し得る新規な技術を見出したことによ
り，画期的な不可逆減磁の改善に至ったのである。Means for Solving the Problems As a means for solving these problems, the present inventors have conducted intensive studies on the fundamental improvement of the irreversible demagnetization due to the structure of the magnet alloy. It has been found that the irreversible demagnetization is remarkably improved as compared with the conventional material by homogenizing the magnetic crystal grains having R and the R-rich grain boundary phase and coating each of the magnetic crystal grains with the grain boundary phase. In order to further enhance these effects, the conventional technology of removing the B-rich phase has led to the discovery of a new technology that was even difficult to anticipate. Irreversible demagnetization at high temperatures even at iHc lower than that of the conventional material is extremely high. It is possible to provide a new permanent magnet alloy which is small and has the same or higher maximum energy product. That is, the present inventors have found a new technology capable of providing good magnetic characteristics that can withstand practical use even in a B content region of less than 2 atomic%, which was no longer high in the prior art and was out of the practical range. This has led to a revolutionary improvement in irreversible demagnetization.
【００１７】 すなわち本発明によれば，Ｒ−Ｆｅ−Ｍ
−Ｂ−Ｃ系合金磁石（但し，ＲはＮｄ，Ｐｒ，Ｃｅ，Ｌ
ａ，Ｙ，Ｓｍ，Ｔｂ，Ｄｙ，Ｇｄ，Ｈｏ，Ｅｒ，Ｔｍ，
Ｙｂより選ばれる少なくとも１種，ＭはＢａ，Ｓｒ，Ｃ
ａ，Ｌｉ，Ｍｇ，Ｂｅより選ばれる少なくとも１種）で
あって，該合金の磁性結晶粒の各々が，０．０５〜１６
重量％のＣを含む粒界相で覆われていることを特徴とす
る不可逆減磁率の小さい熱安定性に優れたＲ−Ｆｅ−Ｍ
−Ｂ−Ｃ系永久磁石合金を提供する。That is, according to the present invention, R—Fe—M
-BC alloy magnets (where R is Nd, Pr, Ce, L
a, Y, Sm, Tb, Dy, Gd, Ho, Er, Tm,
At least one selected from Yb, M is Ba, Sr, C
a, Li, Mg, at least one) selected from Be
There are, each of magnetic crystal grains of the alloy, 0.05 to 16
R-Fe-M with excellent weight% of C in less thermal stability irreversible demagnetization, characterized in that covered by including the grain boundary phase
-To provide a BC permanent magnet alloy.
【００１８】ここで該磁性結晶粒は，粒径が好ましくは
0.3〜150μmの範囲にあり, この粒径の各結晶粒を覆っ
ている粒界相の厚みは0.001〜30μmの範囲である。Here, the magnetic crystal grains preferably have a grain size.
The thickness of the grain boundary phase that covers each crystal grain of this grain size is in the range of 0.001 to 30 μm.
【００１９】 本発明磁石の好ましい組成（磁性結晶粒
と粒界相の全体の合金組成）は，原子百分比で，Ｒ（Ｒ
はＮｄ，Ｐｒ，Ｃｅ，Ｌａ，Ｙ，Ｓｍ，Ｔｂ，Ｄｙ，Ｇ
ｄ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂより選ばれる少なくとも１
種）：１０〜３０％，Ｂ：７％以下好ましくは２％未満
（０原子％を含まず），Ｃ：０．１〜２０％，Ｍ：下記
所定％の金属元素Ｍの少なくとも１種（但し２種以上含
む場合のＭ含有合計量は当該元素のうち最も高い上限値
をもつＭの上限値以下），残部がＦｅおよび製造上不可
避的な不純物からなる。ここで，Ｍ元素の含有量（但
し，０原子％を含まず）は， Ｂａ：５％以下，Ｓｒ：５％以下，Ｃａ：７％以下，Ｌ
ｉ：４％以下，Ｍｇ：６％以下，Ｂｅ：４％以下であ
る。The preferred composition of the magnet of the present invention (the total alloy composition of the magnetic crystal grains and the grain boundary phase) is R (R
Are Nd, Pr, Ce, La, Y, Sm, Tb, Dy, G
at least one selected from d, Ho, Er, Tm, and Yb
Species): 10 to 30%, B: 7% or less, preferably less than 2% (not including 0 atomic%), C: 0.1 to 20%, M: at least one of the following predetermined percentages of metal element M ( However, when two or more kinds are contained, the total content of M is the highest upper limit of the elements.
Below the upper limit of M ), and the balance consists of Fe and impurities inevitable in manufacturing. Here, the content of the M element (excluding 0 atomic%) is as follows: Ba: 5% or less, Sr: 5% or less, Ca: 7% or less, L:
i: 4% or less, Mg: 6% or less, Be: 4% or less.
【００２０】〔作用〕本発明合金において不可逆減磁を
小さくする効果はＢが２％以上でも十分発揮されるもの
ではあるが，特にＢが２％未満と少ない場合には，不可
逆減磁が顕著に良好となり，しかも磁気特性は従来材と
同等以上である。[Function] The effect of reducing the irreversible demagnetization in the alloy of the present invention is sufficiently exhibited even when B is 2% or more, but particularly when B is less than 2%, the irreversible demagnetization is remarkable. The magnetic properties are equal to or better than those of the conventional material.
【００２１】更にＭが無添加であっても, 従来材に比べ
て不可逆減磁は小さくなるが，Ｍを前記記載の所定原子
％ (但し, ０原子％を含まず）含有せしめることによ
り，一層効果的に小さくできる。Further, even if M is not added, the irreversible demagnetization is smaller than that of the conventional material. However, when M is contained in the above-mentioned predetermined atomic% (but not including 0 atomic%), it can be further increased. Can be effectively reduced.
【００２２】本発明による永久磁石の特徴は，従来のよ
うに磁石のiHcを極めて高くしなくても高温時の不可逆
減磁が小さいことであり, 例えばパーミアンス係数 (Ｐ
C)が３，iHcが11.3KOeの磁石を環境温度160℃で30分放
置した後, 室温に戻した時, その不可逆減磁率は−9.3
％である。他方，同じくＰC３でiHc 11.9kOeの従来材を
上記と同一の方法で測定した不可逆減磁率が−27.2％で
あり，iHcが0.6kOe大きいにも拘らず大きな劣化を示
す。従ってこのような高温の環境下でも本発明磁石の不
可逆減磁特性は, 従来材に比べて十分低いiHcでも極め
て良好であり, この点でまったく新規な永久磁石である
といえる。A feature of the permanent magnet according to the present invention is that the irreversible demagnetization at high temperatures is small even if the iHc of the magnet is not extremely high as in the prior art. For example, the permeance coefficient (P
C ) is 3 and iHc is 11.3 KOe.When left at room temperature for 30 minutes at an ambient temperature of 160 ° C, when the temperature is returned to room temperature, the irreversible demagnetization rate is −9.3.
%. On the other hand, also the irreversible demagnetization of the conventional material of iHc 11.9KOe was measured by the above same method at P C 3 is -27.2%, showing a significant deterioration despite iHc is greater 0.6KOe. Therefore, the irreversible demagnetization characteristic of the magnet of the present invention is extremely good even in such a high temperature environment even at iHc sufficiently lower than that of the conventional material, and it can be said that the magnet is a completely novel permanent magnet in this respect.
【００２３】一方，本発明磁石の磁気特性については等
方性焼結磁石では，Ｂr≧4000(G),iHc≧4000(Oe), (Ｂ
Ｈ)max≧４(MGOe), 異方性焼結磁石では, Ｂr≧7000
(G),iHc≧4000(Oe), (ＢＨ)max≧10(MGOe)であり, 従来
のＲ-Ｆe-Ｂ系永久磁石と同等以上の値を有する。On the other hand, regarding the magnetic characteristics of the magnet of the present invention, Br ≧ 4000 (G), iHc ≧ 4000 (Oe), (B
H) max ≧ 4 (MGOe), Br ≧ 7000 for anisotropic sintered magnet
(G), iHc ≧ 4000 (Oe), (BH) max ≧ 10 (MGOe), which are equal to or higher than the conventional R-Fe-B permanent magnet.
【００２４】このような新規な不可逆減磁特性は，本発
明磁石を構成している各磁性結晶粒の周囲を適切なＣ含
有量をもつ非磁性相で覆ったことによって得られたもの
である。即ち, 本発明者等は非磁性相である粒界相にＣ
(炭素) の所定量を含有せしめることにより, つまり該
相の16重量％以下がＣとなるように, 好ましくは0.05〜
16重量％の範囲になるように含有させることにより, こ
の非磁性相をより均質にし, 不可逆減磁特性を改善でき
ることを見い出した。更には磁石中に，Ｍを前記記載の
所定原子％ (但し０原子％含まず）含有させることによ
り，一層効果的となることを見出した。Ｍの含有は磁性
結晶粒相及び粒界相における原子拡散を促進し，こらの
相を均質化すると共に不純物相の生成を抑制していると
推定される。つまり, このようなＣ含有非磁性相で各磁
性結晶粒を被覆すれば，従来材と同等のＢ含有量でも不
可逆減磁を改善することができること，更にはＢを２原
子％未満に低減することにより，磁気特性は従来の同等
レベル以上でありながら不可逆減磁が画期的に改善さ
れ, 更に，前記Ｍを含有させるとその効果は一層良好と
なることが明らかとなった。Such a novel irreversible demagnetization characteristic is obtained by covering each magnetic crystal grain constituting the magnet of the present invention with a nonmagnetic phase having an appropriate C content. . That is, the present inventors have found that the grain boundary phase, which is a non-magnetic phase, has C
(Carbon), so that less than 16% by weight of the phase is C, preferably from 0.05 to
It has been found that the inclusion of 16% by weight makes the nonmagnetic phase more homogeneous and improves the irreversible demagnetization characteristics. Furthermore, it has been found that the effect becomes more effective when M is contained in the above-mentioned predetermined atomic% (but not including 0 atomic%) in the magnet. It is presumed that the inclusion of M promotes atomic diffusion in the magnetic crystal grain phase and the grain boundary phase, homogenizes these phases and suppresses the formation of impurity phases. In other words, if each magnetic crystal grain is coated with such a C-containing nonmagnetic phase, irreversible demagnetization can be improved even with the same B content as that of the conventional material, and further, B is reduced to less than 2 atomic%. Thus, it has been clarified that the irreversible demagnetization is remarkably improved while the magnetic characteristics are equal to or higher than the conventional level, and that the effect is further improved when M is contained.
【００２５】〔発明の詳述〕本発明磁石はＣ (炭素) の
利用の仕方に大きな特徴があるので先ずこの点から説明
する。[Detailed Description of the Invention] The magnet of the present invention has a great feature in the use of C (carbon).
【００２６】従来より, この種の磁石において一般にＣ
は不可避的に混入する不純物元素とされており, 特別の
ことがない限り積極的に添加する合金元素とは扱われて
いなかった。例えば前出特開昭59-46008号公報では，Ｃ
でＢの一部を置換することを開示するが，これは磁石中
のＢの含有量を２〜28原子％と規定し２原子％未満のＢ
量では保磁力iHcが１kOe未満になるので２原子％以上の
Ｂ量を必要とするが，Ｂの多量の含有ではコストが高く
なるのでコストダウンのメリットから，この場合にはＢ
の一部をＣで置換することが可能であると述べられてい
るに過ぎない。更に特開昭59-163803号公報にはＲ-Ｆe-
Ｃo-Ｂ-Ｃ系磁石が開示され，磁石中のＢの含有量を２
〜28原子％, Ｃの含有量を４原子％以下と規定し，Ｂと
Ｃの具体的な併用を開示しているが，Ｃの併用にも拘ら
ずＢの含有量を２原子％以上を必須とし，２原子％未満
のＢ量では，上記特開昭59-46008号公報と同様にiHcが
１kOe未満となると説明されている。すなわち，該公報
が指摘するように，Ｃは磁気特性を低下させる不純物で
あると把握されており, 例えば粉末の成形時に用いる滑
剤等からのＣの混入は不可避であり, また，これを完全
に取り除く操作はコストアップを招くという理由からハ
ードフエライト磁石相当のＢr 4000Ｇまでなら，Ｃの含
有量として４原子％以下を許容できると提案するもので
あり，Ｃは磁気特性については消極的な作用をもつもの
であり必ずしもＣを必須とはしていない。またＣ含有の
粒界相（非磁性相）の形成についてはこれらの公報では
全く示唆されていない。Conventionally, in this type of magnet, generally C
Is considered to be an unavoidable impurity element, and was not treated as an alloying element to be actively added unless otherwise specified. For example, in Japanese Patent Application Laid-Open No. 59-46008, C
Discloses that a part of B is replaced with B, which defines the content of B in the magnet as 2 to 28 atomic% and less than 2 atomic% of B.
Since the coercive force iHc becomes less than 1 kOe, the amount of B is required to be 2 atomic% or more. However, if a large amount of B is contained, the cost becomes high.
It is only stated that it is possible to replace a part of C with C. Further, JP-A-59-163803 discloses R-Fe-
A Co-BC-based magnet is disclosed, and the content of B in the magnet is reduced by 2%.
-28 atomic%, the content of C is specified to be 4 atomic% or less, and a specific combination of B and C is disclosed. It is indispensable that when the amount of B is less than 2 atomic%, iHc is less than 1 kOe as in the above-mentioned JP-A-59-46008. That is, as pointed out by the gazette, it is understood that C is an impurity which lowers the magnetic properties. For example, it is inevitable that C is mixed in from a lubricant or the like used at the time of powder molding, and it is completely eliminated. It is proposed that the removal operation can increase the cost, so that up to Br 4000G, which is equivalent to a hard ferrite magnet, C content of 4 atomic% or less can be tolerated. C has a negative effect on magnetic properties. And C is not necessarily required. Further, these publications do not suggest the formation of a C-containing grain boundary phase (nonmagnetic phase).
【００２７】さらに特開昭62-13304号公報ではＲ-Ｆe-
Ｃo-Ｂ-Ｃ系磁石において，耐酸化性を改善するために
はＣ量が多いと良くないと教示し，Ｃの含有量を0.05重
量％(原子百分比で約0.3％) 以下に抑制することを提案
し，更に他の出願人による特開昭63-77103号公報でも同
じ目的からＣを1000ppm以下にすることを提案してい
る。このように従来においてＣは磁気特性および耐酸化
性について消極的元素とされており, 必須の添加元素と
はされていなかった。Further, Japanese Patent Application Laid-Open No. Sho 62-13304 discloses that R-Fe-
In order to improve the oxidation resistance of Co-BC-based magnets, it is suggested that a large amount of C is not good, and that the content of C should be suppressed to 0.05% by weight (about 0.3% in atomic percentage). In addition, Japanese Patent Application Laid-Open No. 63-77103 by another applicant also proposes to reduce C to 1000 ppm or less for the same purpose. As described above, conventionally, C has been regarded as a passive element in terms of magnetic properties and oxidation resistance, and has not been regarded as an essential additive element.
【００２８】本発明者等は，ＣをＢの単なる置換元素と
して含有させるのではなく，磁性結晶粒を包囲する非磁
性相 (粒界) 中にＣを積極的に含有させるという添加の
仕方をするならば，従来の常識に反してＣは磁石の不可
逆減磁の改善に大きく寄与できることを見い出したもの
であり，更にはＣと共にＭを磁石中に含有させることに
よって一層これらの効果が有利に発現することを見出し
た。即ち, このような非磁性相へのＣの含有によって，
Ｂの含有量が公知の通常範囲であっても従来に比べて低
いiHcで不可逆減磁が改善されるのであるが，特に２原
子％未満のＢ量の場合にはその効果が更に著しいものに
なることがわかった。尚，従来ではＢの含有量が２原子
％未満ではiHcが１kOe以下になるとされていたのである
が，本発明では２原子％未満のＢ量であってもiHcは４k
Oe以上となる。このような本発明による新規な効果は磁
性結晶粒の各々を包囲するＣ含有粒界相の形成並びにＣ
含有粒界相及び磁石中へのＭの含有によってもたらさ
れ，このことから, これまでの磁気特性の低下及び耐酸
化の劣化をもたらしていたＣを消極元素とする従来磁石
とは全く異なり, Ｃを必須成分とする新規な磁石の発明
を完成することができた。The present inventors have proposed a method of adding C not only as a mere substitution element of B but also as a method of positively containing C in a nonmagnetic phase (grain boundary) surrounding magnetic crystal grains. If so, it has been found that C can greatly contribute to the improvement of the irreversible demagnetization of the magnet, contrary to the conventional wisdom. Further, by containing M together with C in the magnet, these effects become more advantageous. Was found to be expressed. That is, due to the inclusion of C in such a nonmagnetic phase,
Irreversible demagnetization can be improved at a lower iHc than before even if the B content is within the known normal range, but the effect is even more remarkable especially when the B content is less than 2 atomic%. It turned out to be. Conventionally, when the B content is less than 2 atomic%, iHc is 1 kOe or less, but in the present invention, iHc is 4 kOe even when the B content is less than 2 atomic%.
Oe or more. Such novel effects according to the present invention include the formation of a C-containing grain boundary phase surrounding each of the magnetic crystal grains and the formation of a C-containing grain boundary phase.
This is caused by the inclusion of M in the contained grain boundary phase and the magnet, which is completely different from the conventional magnet with C as the depolarizing element, which has caused the deterioration of the magnetic properties and the deterioration of oxidation resistance. The invention of a new magnet containing C as an essential component was completed.
【００２９】この場合, 磁性結晶粒の各々を包囲するＣ
含有粒界相は，Ｃ以外に磁石を構成している合金元素の
少なくとも１種以上を含むものである。このような不可
逆減磁の改善をもたらす理由については以下のように推
察する。In this case, C surrounding each of the magnetic crystal grains
The contained grain boundary phase contains at least one or more alloying elements constituting the magnet in addition to C. The reason for such improvement of irreversible demagnetization is speculated as follows.
【００３０】Ｃ含有粒界相が上記磁性結晶粒を構成して
いる合金元素の少なくとも１種以上を含むことは既に述
べたが，このうちＦe又はＣoの遷移金属元素はα-Ｆeや
Ｒ(Ｆe,Ｃo)2等の軟質な磁性相の生成を招きやすく，こ
れらの相が僅かに生成しても逆磁区核の発生及びその成
長を促進し，不可逆減磁の劣化をもたらす。これに対し
て, 本発明による永久磁石合金の粒界相では，不定比な
Ｒ-Ｆe-Ｍ-Ｃ系の金属間化合物が生成していると推定さ
れ，これにより上記不純物の生成が抑制されていると考
えられる。このことは，該粒界相が均質な非磁性相であ
るということであり, これにより逆磁区核の発生が抑制
されると推定される。又，Ｍは，磁性結晶粒内の原子拡
散を促進することにより，均質な結晶粒としiHcを向上
させると推定され, これにより不可逆減磁率は改善され
る。Although it has been described above that the C-containing grain boundary phase contains at least one or more of the alloying elements constituting the magnetic crystal grains, the transition metal element of Fe or Co is α-Fe or R ( Soft magnetic phases such as Fe, Co) 2 are likely to be generated, and even if these phases are generated slightly, the generation and growth of reverse magnetic domain nuclei are promoted, and the irreversible demagnetization is deteriorated. On the other hand, in the grain boundary phase of the permanent magnet alloy according to the present invention, it is presumed that a non-stoichiometric R-Fe-MC intermetallic compound is generated, thereby suppressing the generation of the impurities. It is thought that it is. This means that the grain boundary phase is a homogeneous non-magnetic phase, which is presumed to suppress the generation of reverse domain nuclei. Further, it is presumed that M promotes the diffusion of atoms in the magnetic crystal grains to make the crystal grains uniform and improve iHc, thereby improving the irreversible demagnetization rate.
【００３１】一方，Ｂを２原子％未満としても不可逆減
磁は著しく改善されるが，これは従来材では必ず存在す
るＢリッチ相が抑制されたことによると推定される。つ
まりこの場合も上記同様Ｂリッチ相が逆磁区発生点とな
っていたと考えられる。尚，従来においてはＢを２％未
満にすると，α-Ｆeの生成が容易となり磁気特性の著し
い劣化が生じると報告されているが，本発明による永久
磁石合金では，Ｃ含有粒界相によりα-Ｆeの生成が抑制
され，従来材と同等以上の特性レベルが可能となる。On the other hand, even if B is less than 2 atomic%, the irreversible demagnetization is remarkably improved, but this is presumed to be due to the suppression of the B-rich phase which always exists in the conventional material. That is, also in this case, it is considered that the B-rich phase was the reverse magnetic domain generation point as described above. Conventionally, it has been reported that if B is less than 2%, α-Fe is easily formed and the magnetic properties are significantly deteriorated. However, in the permanent magnet alloy according to the present invention, α is reduced due to the C-containing grain boundary phase. The generation of -Fe is suppressed, and a characteristic level equal to or higher than that of the conventional material can be achieved.
【００３２】このように，本発明者等は個々の磁性結晶
粒をＣ含有粒界相で被覆し，更に磁石中にＭを含有せし
めることにより, 従来材に比べて低いiHcでも不可逆減
磁を著しく改善せしめ，特に高温での改善効果が大きく
更にＢ含有量の低減により一層その効果が著しくなるこ
とを見出し, 公知の技術では困難であった熱安定性の良
好な永久磁石を発明するに至った。As described above, the present inventors coated the individual magnetic crystal grains with the C-containing grain boundary phase and further included M in the magnet, thereby achieving irreversible demagnetization even at a lower iHc than the conventional material. It was found that the effect was remarkably improved, especially at high temperatures, and the effect was further enhanced by reducing the B content. Thus, a permanent magnet having good thermal stability, which was difficult with known techniques, was invented. Was.
【００３３】 このＣ含有粒界相は，前記のようにＣ以
外に，磁石を構成している合金元素の少なくとも１種以
上を含んでいるが，そのＣ含有量は粒界相組成において
１６重量％以下（０重量％を含まず）であることが必要
である。すなわち，粒界相中のＣは該粒界相を均質な非
磁性相とするだけでなく，Ｂの減少に伴うｉＨｃの低下
を抑制する効果をもたらすことから，その含有量は粒界
相の組成において好ましくは０．０５〜１６重量％，更
に好ましくは，０．１〜１６重量％を必要とする。Ｃの
含有量が０．０５重量％未満では粒界相を均質な非磁性
相にすることが不十分でｉＨｃが４ＫＯｅ未満となるこ
ともある。一方，粒界相中のＣ量が１６重量％を超える
と磁石のＢｒの低下が著しくもはや実用が困難となる。
また，本発明磁石合金では粒界相中のＣ濃度は磁性結晶
粒のＣ濃度よりも一般に高い。後記実施例に示す粒界相
中含有量（重量％）は，計算してみれば明らかである
が，合金組成（原子比）中のＣの含有割合よりも高くな
っている。 The C-containing grain boundary phase contains at least one or more alloying elements constituting the magnet, in addition to C, as described above. The C content is 16 wt% in the grain boundary phase composition. % (Not including 0% by weight). That is, C in the grain boundary phase not only makes the grain boundary phase a homogeneous non-magnetic phase, but also has the effect of suppressing the decrease in iHc due to the decrease in B. The composition preferably requires 0.05 to 16% by weight, more preferably 0.1 to 16% by weight. When the content of C is less than 0.05% by weight, it is insufficient to make the grain boundary phase a homogeneous nonmagnetic phase, and the iHc may be less than 4KOe. On the other hand, when the amount of C in the grain boundary phase exceeds 16% by weight, the Br of the magnet is remarkably reduced, making practical use difficult.
In the magnetic alloy of the present invention, the C concentration in the grain boundary phase is determined by the magnetic crystal.
Generally higher than the C concentration of the grains. Grain boundary phase shown in Examples below
Medium content (% by weight) is clear when calculated
Is higher than the content of C in the alloy composition (atomic ratio).
ing.
【００３４】この粒界相については個々の磁性結晶粒を
均一に被覆することが重要であるが，その厚みは0.001
μm未満ではiHcの低下が著しく, 又30μmを超えるとＢr
がもはや本発明で意図する値を満足しなくなるので0.00
1μm〜30μmの範囲, 好ましくは0.005μm〜15μmの範囲
とするのがよい。なおこの厚みは粒界三重点も含むもの
である。この厚みはTEMを用いて測定することができる
(後記の実施例でもこの測定によった) 。It is important for the grain boundary phase to coat each magnetic crystal grain uniformly, but the thickness is 0.001.
If it is less than μm, iHc decreases remarkably, and if it exceeds 30 μm, Br
No longer satisfies the value intended in the present invention,
The range is 1 μm to 30 μm, preferably 0.005 μm to 15 μm. Note that this thickness also includes the grain boundary triple point. This thickness can be measured using a TEM
(This measurement was also used in Examples described later).
【００３５】一方，この粒界相で囲われる各磁性結晶自
身は周知のＲ-Ｆe-Ｂ-(Ｃ) 系永久磁石と同様の組成で
あってもよい。しかしＢが低量であっても本発明磁石の
場合には良好な磁気特性を発現できる。本発明の合金磁
石の組成 (磁性結晶粒と粒界相とを併せた全体の組成)
は，好ましくは原子百分比でＲ：10〜30％, Ｂ：７％以
下望ましくは２％未満（０原子％を含まず），Ｍ：下記
所定％の金属元素Ｍの少なくとも１種以上 (但し２種以
上含む場合のＭの含有合計量は当該元素のうち最も大き
いＭの値以下, 但し０原子％を含まず。),Ｃ：0.1 〜20
％, 残部がＦeおよび製造上不可避的な不純物からな
る。Ｍ元素の含有量（０原子％は含まず）は，Ｂa：５
％以下，Ｓr：５％以下，Ｃa：７％以下，Ｌi：４％以
下，Ｍg：６％以下，Ｂe：４％以下である。On the other hand, each magnetic crystal itself surrounded by the grain boundary phase may have the same composition as a well-known R-Fe-B- (C) -based permanent magnet. However, even with a small amount of B, the magnet of the present invention can exhibit good magnetic properties. Composition of alloy magnet of the present invention (overall composition including magnetic crystal grains and grain boundary phase)
Is preferably R: 10 to 30% and B: 7% or less, desirably less than 2% (not including 0 atomic%), and M: at least one or more of the following predetermined percentages of metal elements M (2% or less). The total content of M when containing more than one species is not more than the largest value of M among the elements, but not including 0 atomic%.), C: 0.1 to 20
%, The balance consists of Fe and impurities inevitable in manufacturing. The content of M element (excluding 0 atomic%) is Ba: 5
%, Sr: 5% or less, Ca: 7% or less, Li: 4% or less, Mg: 6% or less, Be: 4% or less.
【００３６】本発明において，磁石中の総Ｃ含有量は好
ましくは0.1〜20原子％である。磁石中の総Ｃ含有量が2
0原子％を超えるとＢrの低下が著しく, 本発明で目的と
する等方性焼結磁石としてのＢr≧４KG, 並びに異方性
焼結磁石としてのＢr≧７KGの値を満足しなくなる。一
方, 0.1原子％未満ではもはや不可逆減磁を改善するこ
とが困難となる。このように磁石中の総Ｃ含有量として
は好ましくは0.1〜20原子％とするが，前述の粒界相中
のＣは不可逆減磁を改善するだけでなく, Ｂの減少に伴
うiHcの低下を抑制する効果をもたらすことから，その
含有量は粒界相の組成において16重量％以下 (０重量％
は含まず),好ましくは0.05〜16重量％, 更に好ましくは
0.1〜16重量％を必須とする。Ｃの原料としては，カー
ボンブラック, 高純度カーボン又はＮd-Ｃ, Ｆe-Ｃ等の
合金を用いることができる。In the present invention, the total C content in the magnet is preferably 0.1 to 20 atomic%. Total C content in magnet is 2
If it exceeds 0 atomic%, the decrease of Br is remarkable, and the values of Br ≧ 4KG as the isotropic sintered magnet and Br ≧ 7KG as the anisotropic sintered magnet intended in the present invention are not satisfied. On the other hand, if it is less than 0.1 atomic%, it is difficult to improve irreversible demagnetization. As described above, the total C content in the magnet is preferably 0.1 to 20 atomic%, but the C in the grain boundary phase not only improves the irreversible demagnetization, but also decreases iHc with the decrease in B. Content is 16% by weight or less (0% by weight) in the composition of the grain boundary phase.
Is not included), preferably 0.05 to 16% by weight, more preferably
0.1 to 16% by weight is essential. As a raw material of C, carbon black, high-purity carbon, or an alloy such as Nd-C or Fe-C can be used.
【００３７】Ｒは, Ｙ,Ｌa,Ｃe,Ｎd,Ｐr,Ｓm,Ｔb,Ｄy,
Ｇd,Ｈo,Ｅr,Ｔm,及びＹbのうち１種又は２種以上が用
いられる。なお２種以上の混合物であるミッシュメタ
ル，ジジム等も用いることができる。ここでＲを好まし
くは，10〜30原子％とするのは, この範囲内ではＢrが
実用上非常に優れるためである。R is Y, La, Ce, Nd, Pr, Sm, Tb, Dy,
One or more of Gd, Ho, Er, Tm, and Yb are used. Note that a mixture of two or more kinds, such as misch metal and dymium, can also be used. Here, the reason why R is preferably set to 10 to 30 atomic% is that Br is practically excellent in this range.
【００３８】Ｂとしては，純ボロン又はフエロボロンを
用いることができ，その含有量は公知の範囲である２原
子％以上でも従来材に比べて不可逆減磁は改善され, 例
えば７％程度までＢを含有させても本発明の前記目的は
達成されるのであるが，前述のように好ましくはＢは２
原子％未満，更に好ましくは1.8原子％以下においてよ
り一層の効果がある。他方, Ｂ無添加ではiHcが極端に
低下し本発明の目的を達成できなくなる。フエロボロン
としてはＡl,Ｓi等の不純物を含有するものでも用いる
ことができる。As B, pure boron or ferroboron can be used. Even if the content is 2 atomic% or more, which is a known range, the irreversible demagnetization is improved as compared with the conventional material. The above-mentioned object of the present invention can be achieved even if it is contained, but B is preferably 2 as described above.
The effect is further enhanced at less than atomic%, more preferably at most 1.8 atomic%. On the other hand, when B is not added, iHc is extremely reduced and the object of the present invention cannot be achieved. As the ferroboron, those containing impurities such as Al and Si can also be used.
【００３９】ＭはＢa,Ｓr,Ｃa,Ｌi,Ｍg,Ｂeのうち１種
又は２種以上が用いられる。磁石中のＭが０原子％でも
不可逆減磁率は従来品よりも改善されるが，Ｍを前記所
定量を含有せしめることにより，一層効果的に改善する
ことができる。一方Ｍ含有量が前記所定含有量を超える
と，Ｂr, iHcの減少が著しくなって，もはや本発明磁石
の特性を満足しなくなる。M is one or more of Ba, Sr, Ca, Li, Mg, and Be. Although the irreversible demagnetization rate is improved as compared with the conventional product even if M in the magnet is 0 atomic%, it can be more effectively improved by including M in the predetermined amount. On the other hand, when the M content exceeds the predetermined content, the reduction of Br and iHc becomes remarkable, and the characteristics of the magnet of the present invention are no longer satisfied.
【００４０】本発明の永久磁石合金は，前述のように厚
みが0.001〜30μm, 好ましくは0.001〜15μmの範囲のＣ
含有粒界相で各々の磁性結晶粒が覆われているものであ
るが, その磁性結晶粒の粒径は0.3〜150μm,好ましくは
0.5〜50μmの範囲にある。磁性結晶粒の粒径が0.3μm未
満になるとiHcが４KOe未満となり, また150μmを超える
とiHcの低下が著しくなり, 本発明磁石の特徴が損なわ
れる。なおこの結晶粒の粒径の測定はSEMによって, ま
た組成分析はEPMAを用いて正確に行うことができる (後
記実施例でもこれらの測定を行った)。As described above, the permanent magnet alloy according to the present invention has a thickness of 0.001 to 30 μm, preferably 0.001 to 15 μm.
Each magnetic crystal grain is covered with a contained grain boundary phase, and the grain size of the magnetic crystal grain is 0.3 to 150 μm, preferably
It is in the range of 0.5-50 μm. If the grain size of the magnetic crystal grains is less than 0.3 μm, iHc is less than 4 KOe, and if it exceeds 150 μm, the decrease in iHc is remarkable, and the characteristics of the magnet of the present invention are impaired. The particle size of the crystal grains can be accurately measured by SEM, and the composition analysis can be accurately performed by using EPMA (these measurements were also performed in Examples described later).
【００４１】本発明の永久磁石を製造するには，該永久
磁石合金が焼結体の場合には，溶解・鋳造・粉砕・成形
・焼結, 若しくは溶解・鋳造・粉砕・成形・焼結・熱処
理の一連の工程からなる従来同様の方法でも作製可能で
あるが，好ましくは上記製造プロセスにおいて, 鋳造後
に該鋳造合金を熱処理する工程を導入するか，または粉
砕時若しくは粉砕後にＣ原料の一部若しくは全量を二次
添加する工程を導入すること，さらにはこの二つの工程
を組合わせて導入することによって，有利に製造するこ
とができる。他方, 該永久磁石合金が鋳造合金である場
合には，熱間塑性加工法を用いることによって，前述の
効果を発揮する良好な本発明の永久磁石合金を作製する
ことができる。To manufacture the permanent magnet of the present invention, when the permanent magnet alloy is a sintered body, melting, casting, crushing, molding, sintering, or melting, casting, crushing, molding, sintering, Although it can be produced by a conventional method comprising a series of heat treatment steps, preferably, in the above production process, a step of heat treating the cast alloy after casting is introduced, or a part of the C raw material is milled or after milling. Alternatively, it can be advantageously produced by introducing a step of secondary addition of the whole amount, or by introducing these two steps in combination. On the other hand, when the permanent magnet alloy is a cast alloy, a good permanent magnet alloy of the present invention exhibiting the above-described effects can be produced by using the hot plastic working method.
【００４２】このような本発明の永久磁石合金は熱安定
性に優れたものであるが, 一方において耐酸化性につい
ても従来材に比べて画期的に改善されていることから,
従来のように磁石の最外表面を耐酸化性の保護被覆で被
覆しなくても, 磁石自身が極めて優れた耐酸化性を有す
るので, 場合によっては前記保護被覆の形成は不要とな
る。本発明による永久磁石合金から調整された合金粉末
は，従来材に比べて熱安定性および耐酸化性の良好なボ
ンド磁石を提供することができる。Although the permanent magnet alloy of the present invention is excellent in thermal stability, on the other hand, the oxidation resistance is remarkably improved as compared with the conventional material.
Even if the outermost surface of the magnet is not coated with the oxidation-resistant protective coating as in the conventional case, the magnet itself has extremely excellent oxidation resistance, and in some cases, the formation of the protective coating is unnecessary. The alloy powder prepared from the permanent magnet alloy according to the present invention can provide a bonded magnet having better thermal stability and oxidation resistance than conventional materials.
【００４３】このように本発明による永久磁石合金は，
従来のものに比べて熱安定性及び耐酸化性が著しく優
れ, 又，良好な磁気特性を有することから種々の磁石応
用製品に好適に用いられる。磁石応用製品としては，例
えば次の製品が挙げられる。ＤＣブラシレスモーター,
サーボモーター等の各種モーター；駆動用アクチュエー
ター, 光学ビックアップ用F/Tアクチュエーター等の各
種アクチュエーター；スピーカー, ヘッドホン, イヤホ
ン等の各種音響機器；回転センサー, 磁気センサー等の
各種センサー；MRI等の電磁石代替製品；リードリレー,
有極リレー等の各種リレー；ブレーキ, クラッチ等の
各種磁気カップリング；ブザー, チャイム等の各種振動
発振機；マグネットセパレーター, マグネットチャック
等の各種吸着用機器；電磁開閉器, マイクロスイッチ,
ロッドレスエアーシリンダー等の各種開閉制御機器；光
アイソレーター, クライストロン, マグネトロン等の各
種マイクロ波機器；マグネット発電器；健康器具, 玩具
等である。なお，このような磁石応用製品は一例であ
り,これらに限定されるものではない。As described above, the permanent magnet alloy according to the present invention
Compared with conventional products, it has excellent thermal stability and oxidation resistance, and has good magnetic properties, so it is suitable for various magnet applications. Examples of the magnet application products include the following products. DC brushless motor,
Various motors such as servo motors; various actuators such as drive actuators and F / T actuators for optical pickup; various audio equipment such as speakers, headphones, and earphones; various sensors such as rotation sensors and magnetic sensors; Product; Reed Relay,
Various relays such as polarized relays; Various magnetic couplings such as brakes and clutches; Various vibration oscillators such as buzzers and chimes; Various suction devices such as magnet separators and magnet chucks; Electromagnetic switches, micro switches,
Various opening / closing control devices such as rodless air cylinders; various microwave devices such as optical isolators, klystrons and magnetrons; magnet generators; health appliances and toys. It should be noted that such a magnet application product is an example, and the present invention is not limited to this.
【００４４】また，本発明による永久磁石合金の特徴は
熱安定性に優れ,錆にくいことであり高い環境温度で使
用しても, 従来材よりも特性の劣化は少なく, 又従来材
のように磁石品の最外露出表面に耐酸化性保護被膜を形
成しなくても高い磁気特性を保持しながら該磁石自身に
優れた耐酸化性が付与されていることから, 保護被膜が
不要となることはもとより, 特殊な環境用として保護被
膜の必要が生じた場合でも, 磁石内部からの錆の発生が
ないので, 保護被膜を形成するさいの接着性が良好であ
ると共に, 被膜の剥離や被膜厚みの変動による寸法精度
の問題等が解消される。この面からも熱安定性及び耐酸
化性を必要とする用途には最適な永久磁石を提供でき
る。 以下に実施例を挙げて本発明磁石の特性を明らか
にする。Further, the characteristics of the permanent magnet alloy according to the present invention are excellent in thermal stability and resistant to rust, so that even when used at a high environmental temperature, the characteristics are less deteriorated than in the conventional material. Since the magnet itself has excellent oxidation resistance while maintaining high magnetic properties without forming an oxidation-resistant protective coating on the outermost exposed surface of the magnet product, no protective coating is required. Needless to say, even if a protective coating is required for special environments, there is no rust from the inside of the magnet, so the adhesion is good when forming the protective coating, and the peeling of the coating and the thickness of the coating The problem of the dimensional accuracy due to the fluctuation of the size is solved. From this viewpoint, it is possible to provide a permanent magnet that is optimal for applications requiring thermal stability and oxidation resistance. Hereinafter, the characteristics of the magnet of the present invention will be clarified with reference to examples.
【００４５】[0045]
【実施例１】原料として純度99.9％の電解鉄, ボロン含
有量19.32％のフエロボロン合金, 添加金属Ｍとして純
度99％のカルシウム (Ｃa)，さらにＲ元素として純度9
8.5％(不純物として, 他の希土類元素を含有する) のネ
オジウム金属を使用し，組成比 (原子比) として18Ｎd-
72Ｆe-1Ｂ-2Ｃaとなるように計量・配合し，真空中, 高
周波誘導炉で溶解した後, 水冷銅鋳型中に鋳込み, 合金
塊を得た。このようにして得られた合金塊をジョークラ
ッシャーで破砕後，アルゴンガス中でスタンプミルを用
いて−100meshまで粗砕した後, 組成比 (原子比) が18
Ｎd-72Ｆe-1Ｂ-7Ｃ-2Ｃaとなるように, 更に純度99.5％
のカーボンブラックを該粗砕粉に添加し, 次いで, 振動
ミルを用いて平均粒子径５μmまで粉砕した。このよう
にして得られた合金粉末を10 KOeの磁界中１ton/cm2の
圧力で成形した後, アルゴンガス中1120℃で１時間保持
した後，急冷し, 焼結体を得た。[Example 1] Electrolytic iron of 99.9% purity as raw material, ferroboron alloy of boron content of 19.32%, calcium (Ca) of 99% purity as additive metal M, and purity of 9 as R element
8.5% neodymium metal (containing other rare earth elements as impurities) is used, and the composition ratio (atomic ratio) is 18Nd-
It was weighed and blended to 72Fe-1B-2Ca, melted in a high-frequency induction furnace in a vacuum, and then cast into a water-cooled copper mold to obtain an alloy ingot. After crushing the alloy ingot obtained in this way with a jaw crusher and crushing it to −100 mesh using a stamp mill in argon gas, the composition ratio (atomic ratio) was 18%.
Further purity 99.5% to become Nd-72Fe-1B-7C-2Ca
Was added to the crushed powder, and then ground to an average particle size of 5 μm using a vibration mill. The alloy powder thus obtained was molded in a magnetic field of 10 KOe at a pressure of 1 ton / cm 2 , kept in an argon gas at 1120 ° C. for 1 hour, and quenched to obtain a sintered body.
【００４６】なお，比較例１として, 原料のカルシウム
を除き，組成比が18Ｎd-74Ｆe-1Ｂ-7Ｃとした以外は，
実施例１と同一の操作で焼結体を得た。また比較例２と
して，原料はカーボンブラックを除き，実施例１と同一
とし，組成比が18Ｎd-74Ｆe-6Ｂ-2Ｃaとなるように計量
・配合し，実施例１と同様に（但しカーボンブラックは
無添加）溶解後，粗砕，微粉砕，磁場成形し，次いで焼
結，急冷して焼結体を得た。As Comparative Example 1, except that the compositional ratio was changed to 18Nd-74Fe-1B-7C, except that calcium as a raw material was used.
A sintered body was obtained by the same operation as in Example 1. As Comparative Example 2, the raw materials were the same as in Example 1 except for the carbon black, and were measured and blended so that the composition ratio became 18Nd-74Fe-6B-2Ca. After dissolution, the mixture was coarsely crushed, finely crushed, and magnetically molded, then sintered and rapidly cooled to obtain a sintered body.
【００４７】このようにして得られた焼結体の不可逆減
磁率をフラックスメーターを用いて次の手順で測定し
た。 (1) パーミアンス係数(Ｐc)が３になるように形状調整
した上記焼結体試料を50KOeで着磁後, 室温(25℃) でフ
ラックスを測定する。この時のフラックス値をＡ0とす
る。 (2) ついで上記試料を160℃で120分間加熱処理した後,
室温まで冷却し，再びフラックスを測定する。この時の
フラックス値をＡtとする。 (3) 不可逆減磁率の値を次の式で算出する。 上記測定法に基づく焼結体の不可逆減磁率の評価を表１
に示した。表１において「比１」は比較例１の略である
（以下，同じ）。The irreversible demagnetization rate of the thus obtained sintered body was measured by the following procedure using a flux meter. (1) Magnetize the sintered body sample whose shape has been adjusted so that the permeance coefficient (Pc) becomes 3 at 50 KOe, and measure the flux at room temperature (25 ° C.). The flux value at this time is A 0. (2) After heating the above sample at 160 ° C for 120 minutes,
Cool to room temperature and measure the flux again. The flux value at this time is A t. (3) The value of the irreversible demagnetization rate is calculated by the following formula. Table 1 shows the evaluation of the irreversible demagnetization rate of the sintered body based on the above measurement method.
It was shown to. In Table 1, "ratio 1" is an abbreviation for Comparative Example 1 (the same applies hereinafter).
【００４８】表１から明らかのように，実施例１の焼結
体の不可逆減磁率は，−9.3％であるのに対して比較例
１のものでは，−17.9％と本発明の実施例１に比べて劣
っている。更には，本発明による実施例１の焼結体（Ｃ
含有粒界相で各磁性結晶粒を被覆してなる焼結体）で
は，比較例２（Ｃ含有の粒界相を持たない焼結体）に比
較して室温(25℃) における保磁力(iHc) が0.6KOe低い
にも拘わらず, 不可逆減磁率は−9.3 であり，比較例２
（Ｃ含有の粒界相を持たない焼結体）の−27.2％に比べ
て小さくなっている。As is apparent from Table 1, the irreversible demagnetization rate of the sintered body of Example 1 is -9.3%, whereas that of Comparative Example 1 is -17.9%, which is equal to -17.9%. Inferior to. Furthermore, the sintered body (C
The coercive force (at 25 ° C.) at room temperature (25 ° C.) of the sintered body obtained by coating each magnetic crystal grain with the containing grain boundary phase) was higher than that of Comparative Example 2 (the sintered body having no C containing grain boundary phase). Although the iHc) was 0.6KOe lower, the irreversible demagnetization rate was -9.3.
(Sintered body having no C-containing grain boundary phase), which is smaller than -27.2%.
【００４９】また，実施例１の焼結体の粒界相における
Ｃ含有量をEPMAを用いて測定した結果は 4.1重量％であ
った。更に磁性結晶粒の粒径を焼結組織のSEMによる観
察から100個を測定したところ，その範囲は0.8〜32μm
であった。一方,TEMにより測定した粒界相の厚みは0.01
3〜5.2μmであった。これらの値を表１に示した。又室
温(25℃)における磁気特性としてVSMを用いて測定した
Ｂr, iHc及び(ＢＨ)maxの値も表１に示した。このよう
に，本発明による永久磁石合金は比較例１及び２のもの
に比べて熱安定性に優れていることが明らかである。The C content in the grain boundary phase of the sintered body of Example 1 was measured using EPMA and found to be 4.1% by weight. Furthermore, when the grain size of the magnetic crystal grains was measured from 100 observations by SEM of the sintered structure, the range was 0.8 to 32 μm.
Met. On the other hand, the grain boundary phase thickness measured by TEM was 0.01
It was 3-5.2 μm. These values are shown in Table 1. Table 1 also shows the values of Br, iHc and (BH) max measured using a VSM as the magnetic properties at room temperature (25 ° C.). Thus, it is clear that the permanent magnet alloy according to the present invention has better thermal stability than those of Comparative Examples 1 and 2.
【００５０】なお，上記焼結体の耐酸化性の評価（耐候
性試験）として,温度60℃, 湿度90％の恒温・恒湿下で
６ケ月間（5040時間) 放置した時のＢr, iHcの減少率を
測定したところ, Ｂr：−1.05％, iHc：−0.91と極めて
小さく, また外観観察では錆がほとんど認められず, 耐
酸化性が著しく向上していることが明らかになった。こ
れに対して比較例２の焼結体ではわずか１ケ月（720時
間) 後の減少率がＢr：−8.7％, iHc：−3.8％となり，
これ以上の放置時間では, 原形を留めないほど錆が激し
く測定不能であった。このように本発明による永久磁石
合金は比較例２のものに比べて耐酸化性にも優れている
ことがわかる。The oxidation resistance (weather resistance test) of the above sintered body was determined as follows: Br, iHc when left for 6 months (5040 hours) at a constant temperature and humidity of 60 ° C. and 90% humidity. As a result, it was found that Br: -1.05% and iHc: -0.91 were extremely small, and rust was hardly observed in the appearance observation, indicating that the oxidation resistance was significantly improved. On the other hand, in the sintered body of Comparative Example 2, the reduction rates after only one month (720 hours) were Br: -8.7% and iHc: -3.8%.
With longer standing time, rust was so severe that the original shape could not be retained and measurement was impossible. Thus, it can be seen that the permanent magnet alloy according to the present invention has better oxidation resistance than that of Comparative Example 2.
【００５１】[0051]
【実施例２〜５】カーボン量が，表１に示す組成比にな
るように，カーボンブラックを微粉砕時に追添した以外
は，実施例１と同様の操作を行い焼結体を得た。更に，
比較例３として, 18Ｎd-79Ｆe-1Ｂ-2Ｃaとなるように計
量・配合した後, 比較例２と同様な操作を行って焼結体
を得た。また比較例４〜７として, 原料のカルシウムを
除いたうえ,更にはカーボン量が表１の組成となるよう
にした以外は，上記実施例と同様の操作を行って焼結体
を得た。このようにして得られた焼結体の160℃におけ
る不可逆減磁率, 粒界相におけるＣ量, 磁性結晶粒径,
粒界相の厚み及び磁気特性を実施例１と同一の方法で評
価し，その結果を表１に示した。表１から明らかなよう
に，カルシウムを添加した本発明に従う焼結体はいずれ
も各比較例４〜７のカルシウム無添加のものに比べて不
可逆減磁率が小さいことがわかる。なお，比較例３では
粒界相中にＣが含有されておらず，磁気特性は低い値と
なった。Examples 2 to 5 A sintered body was obtained in the same manner as in Example 1, except that carbon black was additionally added at the time of pulverization so that the amount of carbon became the composition ratio shown in Table 1. Furthermore,
As Comparative Example 3, after weighing and blending to obtain 18Nd-79Fe-1B-2Ca, the same operation as in Comparative Example 2 was performed to obtain a sintered body. In addition, as Comparative Examples 4 to 7, sintered bodies were obtained by performing the same operations as in the above-mentioned Examples, except that the raw material calcium was removed and the amount of carbon was changed to the composition shown in Table 1. The irreversible demagnetization rate at 160 ° C of the sintered body thus obtained, the C content in the grain boundary phase, the magnetic crystal grain size,
The thickness and magnetic properties of the grain boundary phase were evaluated in the same manner as in Example 1, and the results are shown in Table 1. As is clear from Table 1, it can be seen that the irreversible demagnetization rate of each of the sintered bodies according to the present invention to which calcium was added was smaller than those of each of Comparative Examples 4 to 7 in which calcium was not added. In Comparative Example 3, C was not contained in the grain boundary phase, and the magnetic properties were low.
【００５２】[0052]
【表１】 [Table 1]
【００５３】[0053]
【実施例６〜１０】原料の溶解時に，表２に示すボロン
（Ｂ）量及びバリウム（Ｂa)量になるように計量・配合
した以外は, 全て実施例１と同様の操作を行って実施例
６〜10の焼結体を得た。また比較例８〜11として, 原料
のバリウムを除き, またボロン量が表２の組成になるよ
うに計量・配合し同様の操作を行って焼結体を得た。比
較例12はボロン (Ｂ) 量を０原子％とした例であり，ボ
ロンを配合しなかった以外は上記実施例と同様な操作を
行い焼結体を得たものである。Examples 6 to 10 The same operations as in Example 1 were carried out except that the amounts of boron (B) and barium (Ba) shown in Table 2 were measured and blended when the raw materials were dissolved. The sintered bodies of Examples 6 to 10 were obtained. Further, as Comparative Examples 8 to 11, sintered materials were obtained by omitting barium as a raw material, measuring and blending such that the amount of boron had the composition shown in Table 2, and performing the same operation. Comparative Example 12 is an example in which the amount of boron (B) was 0 atomic%, and a sintered body was obtained by performing the same operation as in the above example except that boron was not blended.
【００５４】このようにして得られた焼結体の160℃に
おける不可逆減磁率, 粒界相におけるＣ量，磁性結晶粒
径，磁界相の厚み及び磁気特性を実施例１と同一の方法
で評価し，その結果を表２に示した。The irreversible demagnetization rate at 160 ° C., the C content in the grain boundary phase, the magnetic crystal grain size, the thickness of the magnetic field phase and the magnetic properties of the thus obtained sintered body were evaluated in the same manner as in Example 1. The results are shown in Table 2.
【００５５】表２から明らかなようにバリウムを添加し
た実施例６〜10の焼結体は，いずれも対応する各比較例
８〜11のバリウム無添加のものに比べて不可逆減磁率が
小さいことがわかる。又Ｂ含有量が２原子％未満の実施
例８は，Ｂ含有量が２原子％以上の実施例９に比べて，
iHcが0.3KOe低いにも拘わらず, 不可逆減磁率は小さく
なっている。更にＢ含有量が２原子％以上の実施例10に
ついても, 実施例４に比較すると同様なことが言え，Ｂ
含有量が２原子％未満の実施例４では, iHcが0.4KOe低
いにも拘わらず，不可逆減磁率は実施例10より小さくな
っており, 特にＢ含有量が２原子％未満ではＢ≧２原子
％よりも不可逆減磁率は小さい。尚，比較例12のボロン
無添加では (ＢＨ)maxは０であった。As is clear from Table 2, the sintered bodies of Examples 6 to 10 to which barium was added had smaller irreversible demagnetization rates than the corresponding barium-free ones of Comparative Examples 8 to 11. I understand. Example 8 in which the B content is less than 2 atomic% is compared with Example 9 in which the B content is 2 atomic% or more.
The irreversible demagnetization rate is small even though iHc is 0.3KOe lower. Furthermore, the same can be said for Example 10 in which the B content is 2 atomic% or more, as compared with Example 4.
In Example 4 in which the content was less than 2 atomic%, the irreversible demagnetization rate was smaller than that in Example 10 even though iHc was lower by 0.4 KOe. % Is smaller than the irreversible demagnetization rate. In addition, (BH) max was 0 when boron was not added in Comparative Example 12.
【００５６】[0056]
【表２】 [Table 2]
【００５７】[0057]
【実施例１１〜１９】原料として，純度99.9％の電解
鉄, ボロン含有量19.32％のフエロボロン合金,純度99.5
％のカーボンブラック, 表３に示す各種の添加金属Ｍ及
び希土類元素を用いて, 表３に示す組成比となるように
計量・配合し，真空中, 高周波誘導炉で溶解した後, 水
冷銅鋳型中に鋳込み, 合金塊を得た。このようにして得
られた合金塊を680℃で15時間加熱後, 炉内放冷した。
次いで該合金塊をジョークラッシャーで破砕した後, ア
ルゴンガス中でスタンプミルを用いて−100meshまで粗
砕し, 次いで, 振動ミルを用いて平均粒子径５μmまで
粉砕した。このようにして得られた合金粉末を実施例１
と同様の操作を行なって実施例11〜19の焼結体を得た。
また比較例13〜21として，原料のＭ金属を除き，表３の
組成になるように計量・配合した以外は，上記実施例と
同様の操作を行って焼結体を得た。Examples 11 to 19 As raw materials, electrolytic iron having a purity of 99.9%, a ferroboron alloy having a boron content of 19.32%, and a purity of 99.5%
% Of carbon black, various additive metals M and rare earth elements shown in Table 3 were weighed and blended to obtain the composition ratio shown in Table 3, melted in a high frequency induction furnace in a vacuum, and then cooled with a water-cooled copper mold. It was cast into the alloy to obtain an alloy ingot. The thus obtained alloy ingot was heated at 680 ° C for 15 hours and then allowed to cool in a furnace.
Next, the alloy ingot was crushed by a jaw crusher, crushed to -100 mesh using a stamp mill in argon gas, and then crushed to an average particle diameter of 5 μm using a vibration mill. The alloy powder thus obtained was used in Example 1
By performing the same operations as in the above, sintered bodies of Examples 11 to 19 were obtained.
Also, as Comparative Examples 13 to 21, sintered bodies were obtained by performing the same operations as in the above Examples, except that the raw material M metal was excluded and the components were weighed and blended to have the composition shown in Table 3.
【００５８】このようにして得られた焼結体の160℃に
おける不可逆減磁率, 粒界相におけるＣ量, 磁性結晶粒
径, 粒界相の厚み及び磁気特性を実施例１と同一の方法
で評価し，その結果を表３に示した。表３から明らかな
ように，添加元素（Ｍ）を添加した実施例11〜19の焼結
体は, Ｍ元素無添加の比較例13〜21のものに比べて不可
逆減磁率が小さいことがわかる。The irreversible demagnetization rate at 160 ° C., the C content in the grain boundary phase, the magnetic crystal grain size, the thickness of the grain boundary phase and the magnetic properties of the thus obtained sintered body were measured in the same manner as in Example 1. The results were evaluated and the results are shown in Table 3. As is clear from Table 3, the sintered bodies of Examples 11 to 19 to which the additive element (M) was added had smaller irreversible demagnetization rates than those of Comparative Examples 13 to 21 without the addition of the M element. .
【００５9 】[0056]
【表３】 [Table 3]
【００６０】[0060]
【実施例２０】実施例１と同組成の合金微粉末を無磁場
中で成形した以外は，全て実施例１と同様の操作を行っ
て実施例１と同組成の焼結体を得た。比較例22として，
合金微粉末を無磁場中で成形した以外は，比較例１と同
様の操作を行って比較例１と同組成の焼結体を得た。こ
のようにして得られた焼結体の160℃における不可逆減
磁率, 粒界相におけるＣ量, 磁性結晶粒径, 粒界相の厚
み及び磁気特性を実施例１と同一の方法で評価し，その
結果を表４に示した。表４から明らかなように，カルシ
ウムを添加した焼結体は比較例22の無添加のものに比べ
て不可逆減磁率が小さいことが分かる。Example 20 A sintered body having the same composition as in Example 1 was obtained by performing the same operation as in Example 1 except that an alloy fine powder having the same composition as in Example 1 was molded in the absence of a magnetic field. As Comparative Example 22,
A sintered body having the same composition as in Comparative Example 1 was obtained by performing the same operation as in Comparative Example 1, except that the alloy fine powder was molded in a magnetic field-free state. The irreversible demagnetization rate at 160 ° C., the C content in the grain boundary phase, the magnetic crystal grain size, the thickness of the grain boundary phase, and the magnetic properties of the thus obtained sintered body were evaluated in the same manner as in Example 1. Table 4 shows the results. As is clear from Table 4, the irreversible demagnetization rate of the sintered body to which calcium was added was smaller than that of the sintered body to which calcium was not added.
【００６１】[0061]
【表４】 [Table 4]
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) C22C 38/00 - 38/60 H01F 1/053──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. 6 , DB name) C22C 38/00-38/60 H01F 1/053
Claims (4)
し，ＲはＮｄ，Ｐｒ，Ｃｅ，Ｌａ，Ｙ，Ｓｍ，Ｔｂ，Ｄ
ｙ，Ｇｄ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂより選ばれる少なく
とも１種，ＭはＢａ，Ｓｒ，Ｃａ，Ｌｉ，Ｍｇ，Ｂｅよ
り選ばれる少なくとも１種）であって，該合金の磁性結
晶粒の各々が，０．０５〜１６重量％のＣを含む粒界相
で覆われていること，そして，磁性結晶粒と粒界相とを
併せた全体の合金組成が，原子百分比でＲ：１０〜３０
％，Ｂ：７％以下（０原子％を含まず），Ｃ：０．１〜
２０％，Ｍ：下記所定％の元素Ｍの少なくとも１種以上
（但し２種以上含む場合のＭの合計量は当該元素のうち
最も高い上限値をもつＭの上限値以下），残部がＦｅお
よび製造上不可避的不純物からなることを特徴とする不
可逆減磁の小さい熱安定性に優れた永久磁石合金，Ｍ元素の含有量（但し，０原子％を含まず）は ，Ｂａ：５％以下，Ｓｒ：５％以下，Ｃａ：７％以下，Ｌ
ｉ：４％以下，Ｍｇ：６％以下，Ｂｅ：４％以下であ
る。 An R—Fe—MBC alloy magnet (where R is Nd, Pr, Ce, La, Y, Sm, Tb, D
y, Gd, Ho, Er, Tm, Yb, M is at least one selected from Ba, Sr, Ca, Li, Mg, Be) , and each of the magnetic crystal grains of the alloy Is covered with a grain boundary phase containing 0.05 to 16 % by weight of C, and the magnetic crystal grains and the grain boundary phase are
The total alloy composition is R: 10-10-30 in atomic percentage.
%, B: 7% or less (not including 0 atomic%), C: 0.1 to
20%, M: at least one or more of the following predetermined% elements M
(However, when two or more elements are included, the total amount of M is
Below the upper limit of M, which has the highest upper limit), and the balance is Fe or
A permanent magnet alloy characterized by low irreversible demagnetization and excellent thermal stability characterized by being composed of unavoidable impurities in production. The content of element M (excluding 0 atomic%) is Ba: 5% or less. , Sr: 5% or less, Ca: 7% or less, L
i: 4% or less, Mg: 6% or less, Be: 4% or less
You.
ｍの範囲にあり，粒界相の厚みが０．００１〜３０μｍ
の範囲にある請求項１に記載の永久磁石合金。2. The magnetic crystal grains have a particle size of 0.3 to 150 μm.
m, and the thickness of the grain boundary phase is 0.001 to 30 μm.
The permanent magnet alloy according to claim 1, wherein
より高い請求項１または２に記載の永久磁石合金。3. The C concentration of the grain boundary phase is the C concentration of the magnetic crystal grains.
3. The permanent magnet alloy according to claim 1, which is higher .
る請求項１，２または３に記載の永久磁石合金。4. B is less than 2% (excluding 0 atomic%)
Permanent magnet alloy according to claim 1, 2 or 3 that.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3048759A JP2794497B2 (en) | 1991-02-22 | 1991-02-22 | R-Fe-BC permanent magnet alloy with low irreversible demagnetization and excellent thermal stability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3048759A JP2794497B2 (en) | 1991-02-22 | 1991-02-22 | R-Fe-BC permanent magnet alloy with low irreversible demagnetization and excellent thermal stability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04268052A JPH04268052A (en) | 1992-09-24 |
| JP2794497B2 true JP2794497B2 (en) | 1998-09-03 |
Family
ID=12812211
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3048759A Expired - Fee Related JP2794497B2 (en) | 1991-02-22 | 1991-02-22 | R-Fe-BC permanent magnet alloy with low irreversible demagnetization and excellent thermal stability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2794497B2 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62158852A (en) * | 1985-12-28 | 1987-07-14 | S C M:Kk | Permanent magnet material |
| JPH01168844A (en) * | 1987-12-24 | 1989-07-04 | Namiki Precision Jewel Co Ltd | Permanent magnet material |
| JPH01261801A (en) * | 1988-04-13 | 1989-10-18 | Kawasaki Steel Corp | Rare-earth permanent magnet |
-
1991
- 1991-02-22 JP JP3048759A patent/JP2794497B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04268052A (en) | 1992-09-24 |
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