JP4574820B2

JP4574820B2 - Method for producing magnet powder for rare earth bonded magnet

Info

Publication number: JP4574820B2
Application number: JP2000272767A
Authority: JP
Inventors: 悦夫大槻; 謙治小西; 貞晃中松
Original assignee: Santoku Corp
Current assignee: Santoku Corp
Priority date: 2000-09-08
Filing date: 2000-09-08
Publication date: 2010-11-04
Anticipated expiration: 2020-09-08
Also published as: JP2002083706A

Description

【０００１】
【発明の属する技術分野】
本発明は、Ｓｍ₂Ｃｏ₁₇系希土類磁石粉未と樹脂とを含む希土類ボンド磁石を製造するための希土類ボンド磁石用磁石粉末の製造方法に関する。
【０００２】
【従来の技術】
Ｓｍ−Ｃｏ系２−１７型ボンド磁石用磁石粉末は、Ｓｍ、Ｃｏ、Ｆｅ、Ｃｕ及びＺｒを必須成分元素とする。この粉末は、原料成分を所定量配合して真空又は不活性ガス雰囲気で溶解して鋳型に鋳込み、凝固させて合金インゴットを製造し、真空又は不活性ガス雰囲気中において、所定の条件でインゴットを熱処理して１−７型不規則高温相の単相組織とする溶体化熱処理及び時効熱処理を行なった後に粉砕する方法により製造されている。
前記溶体化処理によって得られる合金は、その保磁力が１ｋＯｅ以下の軟磁性を示す。しかし、時効熱処理を行なうことにより、Ｃｕが濃縮した１−５相が網目上に析出してなるセル構造が、２−１７母相に形成されて保磁力が増大し永久磁石特性が発現される。従って、従来においては、溶体化処理以降の工程における組織変化に注目して磁石特性の改善がなされており、さらにボンド磁石化工程において磁石粉末の充填率向上のため粉体物性の最適化に意が注がれ、現在では(ＢＨ)max＞１２ＭＧＯｅの高特性ボンド磁石が生産されるに至っている。
ところで、近年、ボンド磁石はその成形の容易性、機械強度の信頼性等のため、その用途が広がっており、それを用いた機器の小型化、省エネルギー化の要求が益々厳しくなっており、さらに高エネルギー積及び高保磁力を有し、また角型性が改善されるＳｍ−Ｃｏ系ボンド磁石の開発が望まれている。
【０００３】
【発明が解決しようとする課題】
本発明の目的は、高保磁力、高残留磁化で、しかも角型性の良い、Ｓｍ₂Ｃｏ₁₇系希土類磁石粉未を、容易に得ることができる希土類ボンド磁石用磁石粉末の製造方法を提供することにある。
【０００４】
【課題を解決するための手段】
本発明者らは、上記課題を解決するために鋭意検討した。まず、Ｓｍ−Ｃｏ系２−１７型希土類磁石粉末の製造過程における各合金組織を詳細に観察し、磁石特性と合金組織との関係を探求した。その結果、凝固合金組織に存在するＺｒリッチ相(成分組成分析ではＳｍＣｏ₃相又はＳｍ₂Ｃｏ₇相に近い)が時効処理後でも存在し、結果的に２−１７母相のＺｒ含有量の不足にともなう保磁力低下をきたしていることが判った。そこで、高保磁力を有する磁石粉末を得るために、凝固合金組織中、あるいは溶体化処理前の合金組織中にＺｒリッチ相が出現しない方法について検討し、各種溶解鋳造法を試みた。その結果、合金溶湯をある冷却速度以上の範囲で鋳造することによりＺｒリッチ相の出現が抑制され、さらに冷却速度が速すぎると結晶粒が微細化しすぎて磁場成形時の結晶配向が不十分となり残留磁化を劣化させることが判った。そこで、このような条件を容易に満たすことが可能な方法として、溶湯を一定の速度で冷却することができ、しかも効率良く連続的な生産が可能なストリップキャスト法による条件を見出した。更に、インゴットの各部の組織を詳細に調査したところ、インゴットのなかで最後に凝固する箇所、すなわち引け巣の領域にＺｒリッチ相の存在比の高い領域と組成偏析があり、また表面領域酸化物の濃縮相があり、これらの組織不整が磁石特性の特に角型性を劣化させることが判った。これらの問題もストリップキャスト法により解決できることを突き止めた。また、ストリップキャスト法により得られる薄帯は、鋳型により得られるインゴットよりも機械的な粉砕が容易で、微粉の発生が抑制され特性劣化、作業性の問題も解決できる。
更に、従来の溶体化工程において、焼結型磁石の工程に類似して液相出現温度で熱処理を加えているが、その工程においてストリップキャスト法による薄帯の微細組織が粗大化してその後の熱処理では解消しがたい組織不均一をきたし、ひいては磁気特性が劣化することが判った。そこで、溶体化熱処理を液相出現温度より低い温度で行なうことにより、微細なストリップキャスト合金がダイレクトに単相に変化して均質な組織が得られ、磁気特性が改善されることを見出して本発明を完成した。
【０００５】
すなわち本発明によれば、Ｓｍ、Ｃｏ、Ｆｅ、Ｃｕ及びＺｒを含む、Ｓｍ₂Ｃｏ₁₇系希土類磁石粉末含有希土類ボンド磁石用合金溶湯を、ストリップキャスト法により、周速０．１〜１．５ｍ／秒で回転するＣｕ又はＭｏ製の冷却ロールに傾注し、連続的に厚さ１ｍｍ以下に凝固させて合金薄帯を得、次いで、合金液相出現温度より３〜２０℃低い温度で溶体化熱処理をし、時効熱処理及び粉砕することを特徴とする希土類ボンド磁石用磁石粉末の製造方法が提供される。
【０００６】
【発明の実施の形態】
以下、本発明を更に詳細に説明する。
本発明の製造方法は、Ｓｍ₂Ｃｏ₁₇系希土類磁石粉末含有希土類ボンド磁石用合金溶湯を、特定条件下に凝固させて薄帯を得、次いで、溶体化熱処理、時効熱処理及び粉砕することを特徴とし、本発明の目的を損なわない範囲で、通常のボンド磁石用粉末の製造方法で行なわれるその他の工程を含んでいても良い。
本発明の製造方法により得られる希土類ボンド磁石用磁石粉末は、Ｓｍ−Ｃｏ系２−１７型希土類磁石粉末を含むボンド磁石に使用する粉末であって、Ｓｍ、Ｃｏ、Ｆｅ、Ｃｕ及びＺｒを必須成分として含む。
【０００７】
本発明の製造方法において、薄帯は、Ｓｍ、Ｃｏ、Ｆｅ、Ｃｕ及びＺｒを含むＳｍ₂Ｃｏ₁₇系希土類磁石原料用の合金溶湯を、周速０．１〜１．５ｍ／秒で回転する冷却ロールに傾注し、連続的に厚さ１ｍｍ以下、好ましくは０．０１〜１．０ｍｍに凝固させて得ることができる。薄帯の厚さが１．０ｍｍを超えると、フリーサーフェース面(冷却ロールに接触しない側)で冷却速度低下に起囚するＺr量の増大が生じる。
合金溶湯の組成は、Ｓｍ、Ｃｏ、Ｆｅ、Ｃｕ及びＺｒを含み、Ｓｍ₂Ｃｏ₁₇系が得られるものであれば、特に限定されず、公知の組成等を参照して適宜決定することができる。
【０００８】
合金溶湯の冷却は、周速０．１〜１．５ｍ／秒で回転する冷却ロールに傾注し、連続的に上記厚さとなるように行なう、特定条件のストリップキャスト法を採用する。この際、Ｃｕ鋳型への鋳造法により、厚い鋳型壁を用いて薄い鋳塊を製造する方法も考えられるが、効率が悪く、しかも特定な冷却条件を保持することが困難であるため、本発明の方法により得られる磁石粉末と同様な磁石粉末は得られ難い。
合金溶湯を回転する冷却ロールに傾注する場合、冷却条件を一定にし、ロールへの供給量を一定にするために、例えば、タンディッシュ又はノズル等を介して冷却ロールに傾注することが好ましい。この際、冷却ロールの材質は熱伝導度の高い金属であればよく、Ｃｕ、Ｍｏ等が最適である。
【０００９】
本発明の製造方法において、溶体化熱処理は、得られた薄帯を、真空又は不活性ガス雰囲気において、多相組織を１−７不規則構造高温相の単相組織にするため固相線より低い温度に保持して溶体化し、急冷する公知の方法に基づいて行なうことができる。なお、液相出現温度及び溶体化温度は合金組成により変化し、適宜条件を設定することができる。
溶体化熱処理は、液相出現温度より３〜２０℃低い温度で加熱し、溶体化処理を行なう。このような溶体化熱処理を行なうことにより、より合金組織を均一化させ、優れた磁気特性を付与することが可能となる。
【００１０】
本発明の製造方法において、時効熱処理は、上記溶体化熱処理よる合金の組成等を勘案して、通常の条件等から適宜選択して行なうことができ、この際所望の永久磁石特性を発現させることができる。時効熱処理は、例えば、８００〜９００℃において、１〜１０時間程度の条件範囲から適宜選択することができる。
【００１１】
本発明の製造方法において、粉砕は、公知の方法で良く、例えば、機械的な粗粉砕及びジェットミル等を用いた微粉砕等により行なうことができる。粉砕して得られる粉末の平均粒径は、特に限定されないが、通常、平均粒径１０〜３０μｍ程度とすることができる。
【００１２】
本発明の製造方法により得られる磁石粉末を用いて希土類ボンド磁石を製造するには、公知の方法により、樹脂と混合し、加圧成形し硬化させる方法等により得ることができる。この際の各条件、樹脂等は選択して適宜決定することができる。
【００１３】
【発明の効果】
本発明の希土類ボンド磁石用磁石粉末の製造方法は、特に、特定の条件下において合金溶湯を冷却させて特定厚さに凝固させた薄帯を、溶体化熱処理、時効熱処理し、粉砕するので、高保磁力、高残留磁化で、しかも角型性の良い、Ｓｍ₂Ｃｏ₁₇系希土類磁石粉未を、容易に得ることができる。更に、溶体化熱処理の加熱を、液相出現温度以下とすることにより、より優れた磁石特性を有する希土類ボンド磁石用磁石粉末を得ることができる。
【００１４】
【実施例】
以下、本発明を実施例により更に詳細に説明するが本発明はこれらに限定されない。
参考例
Ｓｍ、Ｃｏ、Ｆｅ、Ｃｕ及びＺｒ原料金属を所定組成に秤量し、減圧アルゴン雰囲気下１４５０℃に溶解した。得られた合金溶湯を、周速１．５ｍ／秒で回転するＣｕ製ロールにタンディッシュを介して傾注し、平均厚さ０．３ｍｍの薄片を連続的に調製した。得られた合金薄帯の組成は、Ｓｍ２４質量％、Ｆｅ１４．５質量％、Ｃｕ４．６質量％、Ｚｒ２．９質量％及びＣｏ残量であった。
次いで、得られた合金薄帯を、アルゴン雰囲気中１２２０℃で１時間保持した後、１１８０℃で５時間溶体化処理後急冷した。次いで、アルゴン雰囲気中８５０℃で２時間保持した後、徐冷して時効熱処理を加えた。続いて、機械粉砕により１００メッシュ以下に砕いて、希土類ボンド磁石用磁石粉末を調製した。
得られた磁石粉末に、エポキシ樹脂を１．２質量％となるように添加混合した後、圧力７トン／ｃｍ²で加圧成形し、高温槽にて樹脂を硬化させ、外形１０ｍｍ、高さ１５ｍｍの希土類ボンド磁石サンプルを調製した。サンプルの諸特性を表1に示す。サンプルの残留磁化(Ｂｒ)、保磁力(Ｈｃｊ)及びエネルギー積((ＢＨ)max)を常法に従い測定した。結果を表１に示す。
【００１５】
比較例１
合金薄帯の代わりに、参考例と同様な合金溶湯を、水冷Ｃｕ鋳型に鋳込み厚さ５０ｍｍの鋳片を用いた以外は、参考例と同様に希土類ボンド磁石サンプルを調製し、各特性を測定した。結果を表１に示す。なお、得られた鋳片の組成は、参考例と同様であった。
【００１６】
【表１】

【００１７】
実施例２
合金薄帯をアルゴン雰囲気中１２２０℃で１時間保持する工程を、アルゴン雰囲気中１１９０℃で１時間保持する工程に代えた以外は、参考例と同様に希土類ボンド磁石サンプルを調製し、各特性を測定した。結果を表２に示す。なお、用いた合金薄体の液相出現温度は１２００〜１２１０℃であった。
【００１８】
【表２】

【００１９】
表２の結果より、実施例２における溶体化温度１１９０℃は、この合金組成の液相出現温度(１２００〜１２１０℃)以下であり、残留磁化を高い値に維持しながら高保磁力を達成することができた。また、最大エネルギー積も向上していることから、減磁曲線の角型性も改善されていると推定される。
【００２０】
実施例３
Ｓｍ、Ｃｏ、Ｆｅ、Ｃｕ及びＺｒ原料金属を所定組成に秤量し、減圧アルゴン雰囲気下１４５０℃に溶解した。得られた合金溶湯を、表３に示す周速のＣｕ製ロールにタンディッシュを介して傾注し、平均厚さ０．３ｍｍの各種薄片(薄帯)を連続的に調製した。得られた各薄帯の合金組成は、分析誤差の範囲内で参考例と同様であった。得られた各薄帯を、実施例２で調製した薄帯の代わりに用いた以外は、実施例２と同様に各種希土類ボンド磁石サンプルを調製した。得られた各種希土類ボンド磁石サンプルの残留磁化(Ｂｒ)及び保磁力(Ｈｃｊ)を常法により測定した。結果を表３に示す。尚、表３における周速６．０〜２０ｍ/secの結果は参考のものである。
【００２１】
比較例２
薄帯を調製する際のＣｕ製ロールの周速を、表３に示すとおり代えた以外は、実施例３と同様に各種希土類ボンド磁石サンプルを調製し、各特性を測定した。
結果を表３に示す。
【００２２】
【表３】

【００２３】
表３の結果より、残留磁化Ｂｒはストリップキャストのロール周速が高速の範囲で低下することが判る。これは主に薄帯の組織微細化に伴いプレス工程での結晶配向度の低下に起因すると予想される。一方、保磁力(Ｈｃｊ)はロール周速が低速域で低下することが判る。以上のことからロール周速に最適領域があることが判る。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a magnet powder for a rare earth bonded magnet for producing a rare earth bonded magnet containing Sm ₂ Co _17- based rare earth magnet powder and a resin.
[0002]
[Prior art]
The Sm—Co 2-17 type bonded magnet magnet powder contains Sm, Co, Fe, Cu, and Zr as essential component elements. This powder is mixed with a predetermined amount of raw material components, melted in a vacuum or an inert gas atmosphere, cast into a mold, solidified to produce an alloy ingot, and the ingot was formed under a predetermined condition in a vacuum or an inert gas atmosphere. It is manufactured by a pulverization method after performing a solution heat treatment and an aging heat treatment to form a 1-7 type irregular high-temperature single phase structure by heat treatment.
The alloy obtained by the solution treatment exhibits soft magnetism with a coercive force of 1 kOe or less. However, by performing an aging heat treatment, a cell structure in which the 1-5 phase enriched with Cu precipitates on the network is formed in the 2-17 matrix, increasing the coercive force and exhibiting permanent magnet characteristics. . Therefore, in the past, the magnetic properties have been improved by paying attention to the structural changes in the processes after the solution treatment, and further, the powder physical properties have been optimized in order to improve the filling rate of the magnetic powder in the bonded magnetization process. At present, high-performance bonded magnets with (BH) max> 12MGOe have been produced.
By the way, in recent years, the use of bonded magnets has expanded due to the ease of molding, reliability of mechanical strength, etc., and the demands for downsizing and energy saving of equipment using them have become increasingly severe. Development of an Sm—Co based bonded magnet having a high energy product and a high coercive force and improved squareness is desired.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing a magnet powder for a rare earth bonded magnet, which can easily obtain a Sm ₂ Co ₁₇ rare earth magnet powder having high coercive force, high remanent magnetization, and good squareness. There is.
[0004]
[Means for Solving the Problems]
The present inventors diligently studied to solve the above problems. First, each alloy structure in the production process of the Sm—Co 2-17 type rare earth magnet powder was observed in detail, and the relationship between the magnet characteristics and the alloy structure was searched. As a result, a Zr rich phase (similar to SmCo ₃ phase or Sm ₂ Co ₇ phase in the component composition analysis) existing in the solidified alloy structure exists even after aging treatment, and as a result, the Zr content of the 2-17 parent phase It was found that the coercive force was reduced due to the shortage. Therefore, in order to obtain a magnet powder having a high coercive force, a method in which a Zr-rich phase does not appear in a solidified alloy structure or in an alloy structure before solution treatment was examined, and various melt casting methods were tried. As a result, by casting the molten alloy in a range above a certain cooling rate, the appearance of the Zr rich phase is suppressed, and if the cooling rate is too fast, the crystal grains become too fine and the crystal orientation during magnetic field forming becomes insufficient. It was found that the remanent magnetization was degraded. Therefore, as a method capable of easily satisfying such conditions, the present inventors have found a condition by a strip casting method that can cool a molten metal at a constant speed and can efficiently produce continuously. Further, when the structure of each part of the ingot was examined in detail, the area that solidifies last in the ingot, that is, the region of the shrinkage nest, had a region having a high abundance ratio of Zr-rich phase and compositional segregation. It was found that these irregularities in the structure deteriorate the magnet property, particularly the squareness. It was found that these problems can also be solved by strip casting. Further, the ribbon obtained by the strip casting method is easier to mechanically pulverize than the ingot obtained from the mold, and the generation of fine powder is suppressed, and the problems of property deterioration and workability can be solved.
Furthermore, in the conventional solution treatment process, heat treatment is applied at the liquidus appearance temperature, similar to the process of the sintered magnet. In that process, the microstructure of the ribbon is coarsened by the strip casting method, and the subsequent heat treatment is performed. In this case, it was found that the inhomogeneity of the structure that was difficult to resolve was caused and the magnetic properties were deteriorated. Therefore, it was found that by performing solution heat treatment at a temperature lower than the liquid phase appearance temperature, a fine strip cast alloy directly changes to a single phase to obtain a homogeneous structure, and the magnetic properties are improved. Completed the invention.
[0005]
That is, according to the present invention, an Sm ₂ Co _17- based rare earth magnet powder-containing rare earth bonded magnet alloy containing Sm, Co, Fe, Cu and Zr is obtained by a strip casting method at a peripheral speed of 0.1 to 1.5 m. Inclined to a cooling roll made of Cu or Mo rotating at a speed of 1 second / second, and continuously solidified to a thickness of 1 mm or less to obtain an alloy ribbon, and then solutionized at a temperature 3 to 20 ° C. lower than the alloy liquid phase appearance temperature There is provided a method for producing a magnet powder for a rare earth bonded magnet, characterized by heat treatment, aging heat treatment and pulverization.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
The production method of the present invention is characterized by solidifying a molten alloy for rare earth bonded magnet containing a rare earth magnet powder containing Sm ₂ Co ₁₇ under specific conditions to obtain a ribbon, then solution heat treatment, aging heat treatment and pulverization And within the range which does not impair the objective of this invention, the other process performed with the manufacturing method of the normal powder for bonded magnets may be included.
The magnet powder for rare earth bonded magnet obtained by the production method of the present invention is a powder used for a bonded magnet containing Sm—Co 2-17 type rare earth magnet powder, and Sm, Co, Fe, Cu and Zr are essential. Contains as an ingredient.
[0007]
In the production method of the present invention, the ribbon rotates a molten alloy for Sm ₂ Co _17- based rare earth magnet raw material containing Sm, Co, Fe, Cu and Zr at a peripheral speed of 0.1 to 1.5 m / sec. It can be obtained by inclining into a cooling roll and continuously solidifying to a thickness of 1 mm or less, preferably 0.01 to 1.0 mm. If the thickness of the ribbon exceeds 1.0 mm, an increase in the amount of Zr that takes place in the decrease in the cooling rate on the free surface surface (side that does not contact the cooling roll) occurs.
The composition of the molten alloy is not particularly limited as long as it contains Sm, Co, Fe, Cu, and Zr, and an Sm ₂ Co ₁₇ system can be obtained, and can be appropriately determined with reference to known compositions and the like. .
[0008]
The molten alloy is cooled by using a strip casting method under specific conditions in which the molten alloy is poured into a cooling roll rotating at a peripheral speed of 0.1 to 1.5 m / sec and continuously adjusted to the above thickness. At this time, a method of producing a thin ingot by using a thick mold wall by a casting method to a Cu mold is also conceivable, but the efficiency is poor and it is difficult to maintain specific cooling conditions. It is difficult to obtain a magnet powder similar to the magnet powder obtained by this method.
When the molten alloy is tilted to the rotating cooling roll, it is preferably tilted to the cooling roll through, for example, a tundish or a nozzle in order to keep the cooling condition constant and the supply amount to the roll constant. At this time, the material of the cooling roll may be a metal having high thermal conductivity, and Cu, Mo, etc. are optimal.
[0009]
In the production method of the present invention, the solution heat treatment is carried out by using a solid line in order to turn the obtained ribbon into a single-phase structure of a 1-7 disordered high-temperature phase in a vacuum or an inert gas atmosphere. It can carry out based on the well-known method of hold | maintaining at low temperature, forming a solution, and rapidly cooling. The liquid phase appearance temperature and the solution temperature vary depending on the alloy composition, and conditions can be set as appropriate.
Solution heat treatment, heating at 3 to 20 ° C. lower temperature than the liquid phase emergence temperature, will row the solution treatment. By performing such a solution heat treatment, the alloy structure can be made more uniform and excellent magnetic properties can be imparted.
[0010]
In the production method of the present invention, the aging heat treatment can be appropriately selected from normal conditions in consideration of the composition of the alloy by the solution heat treatment, and at this time, desired permanent magnet characteristics are expressed. Can do. The aging heat treatment can be appropriately selected from a condition range of about 1 to 10 hours at 800 to 900 ° C., for example.
[0011]
In the production method of the present invention, the pulverization may be performed by a known method, for example, mechanical coarse pulverization and fine pulverization using a jet mill or the like. The average particle size of the powder obtained by pulverization is not particularly limited, but can usually be about 10 to 30 μm.
[0012]
In order to produce a rare earth bonded magnet using the magnet powder obtained by the production method of the present invention, it can be obtained by a known method such as mixing with a resin, press molding and curing. Each condition, resin, and the like at this time can be selected and appropriately determined.
[0013]
【The invention's effect】
The method for producing a magnet powder for rare earth bonded magnets of the present invention, in particular, is a solution heat treatment, an aging heat treatment, and pulverization of a ribbon obtained by cooling a molten alloy under a specific condition and solidifying to a specific thickness. An Sm ₂ Co ₁₇ rare earth magnet powder having high coercive force and high residual magnetization and good squareness can be easily obtained. Furthermore, the magnet powder for rare earth bond magnets which has the more excellent magnet characteristic can be obtained by making heating of solution heat treatment below the liquid phase appearance temperature.
[0014]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.
Reference Example Sm, Co, Fe, Cu and Zr raw metal were weighed to a predetermined composition and dissolved at 1450 ° C. under a reduced pressure argon atmosphere. The obtained molten alloy was decanted through a tundish onto a Cu roll rotating at a peripheral speed of 1.5 m / sec to continuously prepare flakes having an average thickness of 0.3 mm. The composition of the obtained alloy ribbon was Sm 24 mass%, Fe 14.5 mass%, Cu 4.6 mass%, Zr 2.9 mass%, and Co remaining amount.
Next, the obtained alloy ribbon was kept at 1220 ° C. for 1 hour in an argon atmosphere, and then rapidly cooled after solution treatment at 1180 ° C. for 5 hours. Subsequently, after hold | maintaining at 850 degreeC in argon atmosphere for 2 hours, it annealed and applied aging heat processing. Subsequently, it was pulverized to 100 mesh or less by mechanical pulverization to prepare a magnet powder for a rare earth bonded magnet.
After adding and mixing an epoxy resin to the obtained magnetic powder so as to be 1.2% by mass, it is pressure-molded at a pressure of 7 ton / cm ² , and the resin is cured in a high-temperature bath, and the outer shape is 10 mm, height A 15 mm rare earth bonded magnet sample was prepared. Table 1 shows the characteristics of the sample. The residual magnetization (Br), coercive force (Hcj) and energy product ((BH) max) of the sample were measured according to a conventional method. The results are shown in Table 1.
[0015]
Comparative Example 1
A rare earth bonded magnet sample was prepared in the same manner as in the Reference Example , except that the molten alloy similar to the Reference Example was cast into a water-cooled Cu mold instead of the alloy ribbon, and each characteristic was measured. did. The results are shown in Table 1. In addition, the composition of the obtained slab was the same as that of the reference example .
[0016]
[Table 1]

[0017]
Example 2
A rare-earth bonded magnet sample was prepared in the same manner as in the Reference Example except that the process of holding the alloy ribbon at 1220 ° C. for 1 hour in an argon atmosphere was replaced with the process of holding the alloy ribbon at 1190 ° C. for 1 hour in an argon atmosphere. It was measured. The results are shown in Table 2. In addition, the liquid phase appearance temperature of the used alloy thin body was 1200-1210 degreeC.
[0018]
[Table 2]

[0019]
From the results in Table 2, the solution temperature 1190 ° C. in Example 2 is equal to or lower than the liquid phase appearance temperature (1200 to 1210 ° C.) of this alloy composition, and a high coercive force is achieved while maintaining the residual magnetization at a high value. I was able to. Moreover, since the maximum energy product is also improved, it is estimated that the squareness of the demagnetization curve is also improved.
[0020]
Example 3
Sm, Co, Fe, Cu and Zr raw metal were weighed to a predetermined composition and dissolved at 1450 ° C. under a reduced pressure argon atmosphere. The obtained molten alloy was tilted through a tundish into a Cu roll having a peripheral speed shown in Table 3, and various thin pieces (thin ribbons) having an average thickness of 0.3 mm were continuously prepared. The alloy composition of each obtained ribbon was the same as that of the reference example within the range of the analysis error. Various rare earth bonded magnet samples were prepared in the same manner as in Example 2 except that each obtained ribbon was used in place of the ribbon prepared in Example 2. Residual magnetization (Br) and coercive force (Hcj) of various rare earth bonded magnet samples obtained were measured by a conventional method. The results are shown in Table 3. In addition, the result of the circumferential speed 6.0-20m / sec in Table 3 is a reference thing.
[0021]
Comparative Example 2
Various rare-earth bonded magnet samples were prepared in the same manner as in Example 3 except that the peripheral speed of the Cu roll at the time of preparing the ribbon was changed as shown in Table 3, and each characteristic was measured.
The results are shown in Table 3.
[0022]
[Table 3]

[0023]
From the results of Table 3, it can be seen that the residual magnetization Br decreases in the range where the roll peripheral speed of the strip cast is high. This is presumably due to a decrease in the degree of crystal orientation in the pressing process as the structure of the ribbon is refined. On the other hand, it can be seen that the coercive force (Hcj) decreases in the low speed region of the roll peripheral speed. From the above, it can be seen that there is an optimum region for the roll peripheral speed.

Claims

Sm, Co, Fe, containing Cu and Zr, a molten alloy for Sm ₂ Co ₁₇ based rare earth magnet powder containing rare earth bonded magnet, and casting, Cu rotated at a peripheral speed 0.1～1.5M / sec or Inclined to a cooling roll made of Mo and continuously solidified to a thickness of 1 mm or less to obtain an alloy ribbon, then solution heat treated at a temperature 3-20 ° C. lower than the alloy liquid phase appearance temperature, aging heat treatment and A method for producing a magnet powder for a rare earth bonded magnet, characterized by pulverizing.