JPH06207203A

JPH06207203A - Production of rare earth permanent magnet

Info

Publication number: JPH06207203A
Application number: JP15976591A
Authority: JP
Inventors: Masao Kusunoki; 的生楠; Takehisa Minowa; 武久美濃輪
Original assignee: Shin Etsu Chemical Co Ltd
Current assignee: Shin Etsu Chemical Co Ltd
Priority date: 1991-06-04
Filing date: 1991-06-04
Publication date: 1994-07-26
Anticipated expiration: 2014-02-03
Also published as: JP2853838B2

Abstract

PURPOSE:To produce the high-performance magnet by subjecting alloys specified in phase compsn. to press molding and sintering, then to an aging heat treatment. CONSTITUTION:An alloy mainly consisting of an R2Fc14 phase is used for the alloy A and an alloy contg. R, Co, Fc, B and Ga and consisting of an R2T<1>14 phase and/or R rich phase and a phase mixture composed of one or >=2 kinds among RT24L phase, RT<2>3 phase, RT<2>2 phase and R2T<2>7 phase is used for the alloy B. The alloy B powder is mixed at 1 to 30wt.% with 99 to 70wt.% alloy A powder and the alloy mixture powder is press molded in a magnetic field. The molding is sintered in a vacuum or inert gaseous atmosphere and is then subjected to the aging heat treatment at the sintering temp. or below. As a result, the high-performance magnet having high coercive force, high residual magnetic flux density and high energy product is produced by effectively utilizing the costly additive elements.

Description

^{【発明の詳細な説明】} ^{【０００１】} ^{【産業上の利用分野】本発明は、各種電気、電子機器に}
^{用いられる、磁気特性に優れた希土類永久磁石の製造方}
^{法に関するものである。} ^{【０００２】} ^{【従来の技術】希土類磁石の中でもNd-Fe-Ｂ系磁石は、}
^{主成分であるNdが資源的に豊富でコストが安く、磁気特}
^{性に優れているために、近年益々その利用が広がりつつ}
^{ある。磁気特性向上のための開発研究も、Nd系磁石の発}
^{明以来精力的に行われてきており、数多くの研究や発明}
^{が提案されている。Nd系焼結磁石の製造方法の１つであ}
^{る２種類の組成の異なった合金粉体を混合、焼結して高}
^{性能Nd磁石を製造する方法（以下、２合金法という）に}
^{関しても数々の発明考案が提案されている。} ^{【０００３】これまでに提案されている２合金法を大き}
^{く分けると、３種類に分類することができる。第１の方}
^{法は、混合する原料合金粉体の一方を液体急冷法によっ}
^{て非晶質あるいは微細結晶合金を作製し、それに通常の}
^{希土類合金粉末を混合するか、あるいは両方の原料合金}
^{粉体を共に液体急冷法で作製混合する方法［特開昭63-9}
^{3841、特開昭63-115307、特開昭63-252403、特開昭６63-2}
^{78208、特開平1-108707、特開平1-146310、特開平1-1463}
^{09、特開平1-155603各号公報参照］である。この液体急}
^{冷法による合金を使用する２合金法については、最近50}
^{MGOeを越える磁気特性が得られたと報告[E.Otuki,T.Otu}
^{ka and T.Imai;11th.Int.Workshopon Rare Earth Magne}
^{ts,Pittsburgh,Pennsylvania,USA,October(1990),p.328}
^{参照 ]されている。} ^{【０００４】第２の方法は、混合する２種類の原料合金}
^{粉体を共に主としてＲ}2^Fe14
^{Ｂ化合物とし含有される希土類元素の種類、含有量を変}
^{えた合金を作製して混合焼結する方法である。即ち、含}
^{有するNdリッチ相の量比あるいは希土類元素の種類を変}
^{えた合金を２種類混合する方法［特開昭61-81603、特開}
^{昭61-81604、特開昭61-81605、特開昭61-81606、特開昭}
^{６１−８１６０７、特開昭61-119007、特開昭61-20754}
^{6、特開昭63-245昭3、特開平1-177335各号公報参照］であ}
^る。 ^{【０００５】第３の方法は、一方の合金を主としてＲ} 2
^Fe14
^{Ｂ化合物からなる合金粉末とし、これに各種低融点元素}
^{、低融点合金、希土類合金、炭化物、硼化物、水素化物}
^{等の粉末を混合焼結して、Nd系希土類磁石を製造する方}
^{法 [特開昭60-230959、特開昭61-263201、特開昭62-18140}
^{2、特開昭62-182249、特開昭62-206802、特開昭62-270746、}
^{特開昭63-6808、特開昭63-104406、特開昭63-114939、特開}
^{昭63-272006、特開平1-111843、特開平1-146308各号公報}
^{参照] である。} ^{【０００６】} ^{【発明が解決しようとする課題】従来技術による２合金}
^{法ではNd系磁石合金の真に優れた磁気特性を実現させる}
^{のに適切でなかったり不充分だったりする点が多く存在}
^{する。即ち、前述した第１の方法では磁石合金のエネル}
^{ギ−積は高いが保磁力は約９kOe 程度で、温度上昇によ}
^{って低下するというNd磁石特有の欠点を持ち、実用的に}
^{は不充分な磁石特性である。最も大きな問題点は、磁場}
^{配向性である。第１の方法でも組成を適当に選ぶことに}
^{よって、室温で保磁力を示す合金を得ることができるが}
^{、液体急冷法によって得られる合金は非晶質アモルファ}
^{ス相あるいは微細結晶となるため、微粉にして磁場中で}
^{配向させても特定の結晶方位を磁場方向に配向させるこ}
^{とができない。従って、混合した原料合金粉体を磁場中}
^{成形しても得られる成形体の配向性は悪く、焼結後充分}
^{な磁石特性が得られないことになる。} ^{【０００７】第２の方法においては、磁石合金中のＲ} 2
^Fe14^{Ｂ化合物と共存する相はNdリッチ相あるいはNd}1+
^χFe4^Ｂ4
^{相であり、この両相とも室温では磁性を示さない。従}
^{って、磁性を持たない化合物を混合した場合と同様に、}
^{非磁性粒子の混在が配向性を乱して、磁気特性の優れた}
^{磁石は得られない。また、混合する粉体として各種元素}
^{や種々の化合物を用いる第３の方法においてもこれらの}
^{化合物は磁性をもたないために、磁場中配向時に反磁場}
^{が大きくなって有効磁場強度が減少し、そのため磁場方}
^{向への磁性粒子の回転が不充分となって配向が乱れる。} ^{【０００８】}
^{第３の方法において、混合する粉体に低融点の元素ある}
^{いは合金を利用して磁気特性を向上させようとする提案}
^{があるが、これは焼結中に混合した低融点相が、Ｒ} 2^Fe
14
^{Ｂ化合物の粒界に存在する格子欠陥や酸化物相などのニ}
^{ュークリエーションサイトを除去し、粒界をクリーニン}
^{グして保磁力を向上させるという考え方によるものであ}
^{る。しかし、低融点相の存在は次に述べるような理由か}
^{ら、実際には磁気特性の向上に対して逆に不利な条件と}
^{なっている。低融点相が例えば660 ℃付近から融液とな}
^{っていると、実際の焼結温度1,100 ℃では低融点相の粘}
^{度はかなり小さくなってしまう。その結果、成形体は液}
^{相焼結によって収縮しながら同時に粒の周囲を囲む融液}
^{の粘度が小さいために磁性粒子の回転が容易に起り、配}
^{向が乱れて磁気特性が劣化する。つまり、Nd磁石の液相}
^{焼結における望ましい液相成分は、適当な粘度を保って}
^{粒子の配向を乱さず、かつまた成形体を緻密化し、粒界}
^{を十分にクリーニングアップできることが必要なのであ}
^{る。従来の２合金法においては、液相成分が関与する磁}
^{場配向性と保磁力向上の両方の役割を充分に考慮し、こ}
^{れらが最適な条件となるよう液相合金成分の磁性と融点}
^{を適切に調整してはいなかった。本発明は２合金法にお}
^{ける前述したような欠点を改良し、バランスのとれた磁}
^{気特性に優れた希土類永久磁石の製造方法を提供しよう}
^{とするものである。} ^{【０００９】} ^{【課題を解決するための手段】本発明者等は、かかる課}
^{題を解決するために２合金法を基本的に見直し、磁性体}
^{構成相の種類、特性等を適切に選択し組合せることによ}
^{り充分満足できるバランスのとれた磁気特性が得られる}
^{ことを見出し、製造条件を詳細に検討して本発明を完成}
^{させた。本発明の要旨は、Ａ合金を主としてＲ} 2^Fe14
^{Ｂ相（ここにＲは、Nd、Pr、Dyを主体とする少なくとも１}
^{種以上の希土類元素を表す）から成る合金とし、Ｂ合金}
^{をＲ、Co、Fe、Ｂ、Gaを含有し、かつ合金中の構成相とし}
^てＲ2^Ｔ ¹14
^{Ｂ相および／またはＲリッチ相（ここにＲは上記に同}
^じ、Ｔ ¹ はFe、Co を主体とする遷移金属元素を表す）並
びにＲＴ²4^{Ｌ相、ＲＴ} ²3^相、ＲＴ ²2^相、Ｒ2^Ｔ ²7
^{相およびＲＴ} ²5^{相（ここにＲは上記に同じ、Ｔ} ² はFe、C
o を主体とする遷移金属元素、同遷移金属およびGaとＢ
の内１種または２種、ＬはＢまたはＢとGaを表す）の５
相の内１種または２種以上の相との混合相から成る合金
とし、Ａ合金粉末99〜70重量％に対してＢ合金粉末を１
〜30重量％混合し、該混合合金粉末を磁場中加圧成形
し、該成形体を真空または不活性ガス雰囲気中で焼結
し、さらに焼結温度以下の低温で時効熱処理することを
特徴とする希土類永久磁石の製造方法であり、更に詳し
くは、Ｂ合金に含まれるＲＴ²4^{Ｌ相、ＲＴ} ²3^相、ＲＴ ²2
^相、Ｒ2^Ｔ ²7^{相およびＲＴ} ²5
^{相の５つの構成相の内少なくとも１種以上の相の融点が}
^{７００ ℃以上1,155 ℃以下の金属間化合物であり、少}
^{なくとも１種以上の相が室温以上のキューリー温度を有}
^{する磁性体であり、少なくとも１種以上の相が室温以上}
^{のキューリー温度ならびに結晶磁気異方性を有する磁性}
^{体であることを特徴とする希土類磁石の製造方法である}
^。 ^{【００１０】以下本発明を詳細に説明する。本発明は所}
^{謂２合金法と称する希土類永久磁石（以下、磁石合金Ｃ}
^{という）の製造方法であり、原料となるＡ合金は主とし}
^てＲ 2^Fe14
^{Ｂ化合物相からなり、ＲはＹを含む La,Ce,Pr,Nd,Pm,Sm}
^{,Eu,Gd,Tb,Dy,Ho,Er,Tm,YbおよびLuから選択されるNd、P}
^{r、Dyを主体とする少なくとも１種類以上の希土類元素で}
^{ある。Ａ合金は原料金属を真空または不活性ガス、好ま}
^{しくはAr雰囲気中で溶解し鋳造する。原料金属は純希土}
^{類元素、純鉄、フェロボロン等を使用するが、一般的な}
^{工業生産において不可避な微量不純物は含まれるものと}
^{する。得られたインゴットは、Ｒ}2^Fe14
^{Ｂ相がαFeと希土類リッチ相との包晶反応によって形成}
^{されるため、鋳造後も凝固偏析によってαFe相、Ｒリッ}
^{チ相、あるいはＢリッチ相等が残留する場合がある。本}
^{発明においてはＡ合金中のＲ}2^Fe14
^{Ｂ相が多いほうが望ましいので、必要に応じて溶体化処}
^{理を行う。その条件は真空またはAr雰囲気下、700 〜1,}
^{200 ℃の温度領域で１時間以上熱処理すれば良い。} ^{【００１１】Ｂ合金は主としてＲ、Co、Fe、ＢおよびGaか}
^{ら成る合金で、組成式Ｒ} a^Feb^Coc^Ｂd^Gae
^{（ここにＲは、Ｙを含む La,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb}
^{,Dy,Ho,Er,Tm,YbおよびLuから選択されるNd、Pr、Dyを主}
^{体とする少なくとも１種以上の希土類元素、15≦a ≦40}
^{、０≦b ≦80、５≦c ≦85、０≦d ≦20、0.1≦e ≦20、a}
^+b+c+d+e=100
^{(各原子％) ）で表わされ、Ａ合金と同様に原料金属を}
^{真空または不活性ガス、好ましくはAr雰囲気中で溶解し}
^{鋳造する。原料金属としては純希土類元素、純鉄、純コ}
^{バルト、純ガリウム、フェロボロン等を使用するが、一}
^{般的な工業生産において不可避な微量不純物は含まれる}
^{ものとする。希土類元素Ｒの量a が15原子％未満ではＲ}
^{が少な過ぎるために焼結工程において十分な量の液相が}
^{得られず、焼結体の密度が上がらなくなり、40原子％を}
^{越えると合金の融点が低くなり過ぎて磁気特性の向上効}
^{果がなくなる。Coの量c が５原子％未満ではＲＴ} ²4
^{Ｌ相、ＲＴ} ²3^相、ＲＴ ²2^相、Ｒ2^Ｔ ²7^{相およびＲＴ} ²5
^{相等の各相が出現しなくなり、磁気特性の向上効果が得}
^{られない。Gaの量d が20原子％を越えると合金の飽和磁}
^{束密度が小さくなり高い磁気特性が得られない。また、}
^{液体急冷法によって得られた薄帯を熱処理してもＢ合金}
^{を作製することができる。即ち、液体急冷法において、}
^{急冷後のＢ合金はアモルファス相或は微細結晶相となっ}
^{ており、これを結晶化温度以上の温度で一定時間以上加}
^{熱することにより、結晶化或は再結晶成長させて、本発}
^{明の所定の構成相を析出させることが出来る。} ^{【００１２】この組成範囲においてＢ合金中に主に出現}
^{する相は、Ｒ} 2^Ｔ ¹14^{Ｂ相（主としてＲ}2^Fe14
^{Ｂ相）、Ｒリッチ相（ここにＲは上記に同じ、Ｔ} ¹ はF
e、Co を主体とする遷移金属元素を表す）並びにＲＴ²4
^{Ｌ相、ＲＴ} ²3^相、ＲＴ ²2^相、Ｒ2^Ｔ ²7^{相およびＲＴ} ²5
^{相（ここにＲは上記に同じ、Ｔ} ² はFe、Co を主体とする
遷移金属元素、同遷移金属およびGaとＢの内１種または
２種、ＬはＢまたはＢとGaを表す）等であり、本発明で
は前２相および後５相の内少なくとも１種または２種以
上の相を含むＢ合金を使用することに特徴がある。なお
Ｒリッチ相と表記した相は、Ｒ成分が35原子％以上とな
るＲに富んだ各種の相全てを表すものとする。これら７
種類の相のうち、Ｒ₂ Fe₁₄Ｂ相、Ｒリッチ相の２相は、
従来公知の２合金法や、通常の希土類鉄ボロン系磁石合
金の製造法によっても出現していた相である。残りのＲ
Ｔ²4^{Ｌ相、ＲＴ} ²3^相、ＲＴ ²2^相、Ｒ2^Ｔ ²7^相、ＲＴ ²5
^{相の５種類の相は、Ｂ合金に５原子％以上のCoを添加す}
^{ることにより出現し、本発明の２合金法において特有の}
^{ものである。これら５相はCoを５原子％以上添加するこ}
^{とによって}
^{初めてＢ合金中に平衡相として出現したものである。図}
^{１は本発明のＢ合金の鋳造組織写真を走査電子顕微鏡に}
^{より撮影し、組成をEPMA( 電子プローブＸ線マイクロア}
^{ナライザー )およびＸ線解析により求めた１例でＲＴ}
²4^{Ｌ相、ＲＴ} ²3^相、ＲＴ ²2
^{相、Ｒリッチ相の存在が明確に表されている。本発明}
^{による２合金法は、Ｂ合金中にこれら５相のうち、少な}
^{くとも１種以上含むことを特徴とし、これらの相の存在}
^{によって２合金法で作製された磁石合金に高い磁気特性}
^{を実現することができた。} ^{【００１３】本発明では以上述べたＡ合金、Ｂ合金を特}
^{定割合に混合し、所謂２合金法によって磁石合金Ｃを作}
^{製し、高い磁気特性を発現させることができた。以下、}
^{Ｂ合金におけるこれら混合相の存在が磁石合金の高い磁}
^{気特性をもたらした理由について述べる。まず第１の理}
^{由として、これら混合相が室温以上のキューリー温度を}
^{持つことが挙げられ、これは添加元素Coによって達成さ}
^{れた。さらに、これらの相は特定の結晶方向に結晶磁気}
^{異方性を持つ。従って、主な構成相としてこれらの相の}
^{１種以上を含有するＢ合金粉末を主にＲ} 2^Fe14
^{Ｂ相から成るＡ合金粉末に混合して磁場中配向させる}
^{と、Ｂ合金も強磁性体で磁気異方性を持つため、加えた}
^{磁場方向にほぼ全ての粒子が結晶方向を揃えて配向し、}
^{高い磁気特性が得られることになる。} ^{【００１４】第２の理由は、これらの相の融点がNd系希}
^{土類磁石の液相焼結にとって適当な温度範囲、即ち700}
^{℃以上1,155 ℃以下の範囲となることである。この温度}
^{範囲はNdリッチ相の融点（500 〜 650℃）よりは高く、}
^しかもＲ 2^Fe14
^{Ｂ相の融点（1,155 ℃）以下の温度である。従って、}
^{通常の焼結温度においてNdリッチ相のみが存在していて}
^{融液の粘度が下がり過ぎてしまい、その結果粒子の配向}
^{を乱してしまうようなことがなく、かつまた液相となっ}
^{て粒界をクリーニングしながら密度を上げ、焼結後高い}
^{磁石特性を実現することになる。Co添加によるもう１つ}
^{の効果として、耐食性の向上が挙げられる。Ｂ合金はＡ}
^{合金より希土類元素を多く含有するため酸化劣化しやす}
^{くなるが、Coを添加することにより酸化劣化を防止する}
^{ことができ、安定した磁気特性が得られる。Ｂ合金に添}
^{加されるDyとGaは、両者共焼結後も粒界近傍に多く存在}
^{し、磁石合金Ｃの保磁力を向上させる効果がある。} ^{【００１５】次に２合金法による磁石合金Ｃの製造方法}
^{を述べる。上記のようにして得られたＡ合金およびＢ合}
^{金は、各インゴットを別々に粉砕した後、所定割合に混}
^{合される。粉砕は、湿式又は乾式粉砕にて行われる。希}
^{土類合金は非常に活性であり、粉砕中の酸化を防ぐこと}
^{を目的に、乾式粉砕の場合はAr又は窒素などの雰囲気中}
^{で、湿式粉砕の場合はフロンなどの非反応性の有機溶媒}
^{中で行われる。混合工程も必要に応じて不活性雰囲気又}
^{は溶媒中で行われる。粉砕は一般に粗粉砕、微粉砕と段}
^{階的に行われるが、混合はどの段階で行われても良い。}
^{即ち粗粉砕後に所定量混合し引続いて微粉砕を行っても}
^{よいし、全ての粉砕を完了した後に所定の割合に混合し}
^{てもよい。Ａ、Ｂ両合金がほぼ同じ平均粒径で均一に混}
^{合されることが必要で、平均粒径は0.5 〜20μｍの範囲}
^{が良く、0.5 μｍ未満では酸化され劣化し易く、20μｍ}
^{を越えると焼結性が悪くなる。} ^{【００１６】Ａ合金粉末とＢ合金粉末の混合割合は、Ａ}
^{合金粉末99〜70重量％に対してＢ合金粉末を１〜30重量}
^{％の範囲で混合するのが良く、Ｂ合金粉末が１重量％未}
^{満では焼結密度が上がらなくなり保磁力が得られないし}
^{、30重量％を越えると焼結後の非磁性相の割合が大きく}
^{なり過ぎて、残留磁束密度が小さくなってしまう。得ら}
^{れたＡ合金とＢ合金の混合微粉は、次に磁場中成型プレ}
^{スによって所望の寸法に成型され、さらに焼結熱処理す}
^{る。焼結は900 〜1,200 ℃の温度範囲で真空又はアルゴ}
^{ン雰囲気中にて30分以上行ない、続いて焼結温度以下の}
^{低温で30分以上時効熱処理する。焼結後、磁石合金Ｃの}
^{成形体の密度は対真密度比で95％以上に緻密化しており}
^{高い残留磁束密度が得られる。} ^{【００１７】} ^{【実施例】以下、本発明の具体的な実施態様を実施例を}
^{挙げて説明するが、本発明はこれ}
^{らに限定されるものではない。} ^{（実施例１、比較例１）純度99.9重量％のNd、 Feメタル}
^{とフェロボロンを用いて組成式12.5Nd-6B-81.5Fe（各原}
^{子％）の合金を、高周波溶解炉のAr雰囲気中にて溶解鋳}
^{造した後、このインゴットを1,070 ℃、Ar雰囲気中にて}
^{２０時間溶体化した。これをＡ１合金とする。次に同じ}
^{く純度99.9重量％のNd、Dy、Fe、Ga、Coメタルとフェロボロ}
^{ンを用いて組成式20Nd-10Dy-20Fe-6B-4Ga-40Coの合金を}
^{高周波溶解炉を用いAr雰囲気にて溶解鋳造し、これをＢ}
^{１合金とした。Ａ１合金インゴットとＢ１合金インゴッ}
^{トをそれぞれ別々に窒素雰囲気中にて粗粉砕して30メッ}
^{シュ以下とし、次にＡ１合金粗粉90重量％にＢ１合金粗}
^{粉を10重量％秤量して、窒素置換したＶブレンダー中で}
^{３０分間混合した。この混合粗粉を高圧窒素ガスを用い}
^{たジェットミルにて、平均粒径約５μｍに微粉砕した。}
^{得られた混合微粉末を15kOe の磁場中で配向させながら}
^{、約１Ton/cm} ² の圧力でプレス成型した。次いで、この
成形体はAr雰囲気の焼結炉内で1,070 ℃で１時間焼結さ
れ、さらに530 ℃で１時間時効熱処理して急冷し、磁石
合金Ｃ１を作製した。【００１８】比較のため実施例１と同じ組成となる合金
を従来の１合金法にて製造し、比較例１とした。即ち、
Ａ１、Ｂ１両合金混合後と同じ組成（磁石合金Ｃ１）を
最初から秤量し、溶解、粉砕、焼結、時効熱処理して２
合金法による磁石（実施例１の磁石組成Ｃ１）と磁気特
性を比較した。この磁石合金Ｃ１の組成は、２合金法に
よる実施例１、１合金法による比較例１共に、13.1Nd-
0.8Dy-3.5Co-6.0B--0.3Ga-76.6Fe である。表１に実施
例１と比較例１の両焼結体磁石において得られた磁気特
性の値と焼結体密度を示す。実施例１の磁気特性は比較
例１に比較して、焼結体密度は殆ど同じであるが、残留
磁束密度、保磁力、最大エネルギ−積等、全ての値にお
いて実施例１が大きく勝っている。このように磁石合金
Ｃの組成が全く同一でも磁気特性にはかなりの差が生じ
ており、２合金法がNd磁石の磁気特性向上のために極め
て有効な方法であることを示している。Ｂ１合金の鋳造
状態での金属組織を、図１に走査電子顕微鏡の反射電子
像写真によって示した。写真の明暗から判る通りＢ１合
金中の主な構成相は４つある。各相は、EPMA（電子プロ
ーブＸ線マイクロアナライザー）およびＸ線解析によっ
て、図中に示したようにＲＴ²4^{Ｌ相、ＲＴ} ²3^相、ＲＴ ²2
^{相、Ｒリッチ相であることが判明した。} ^{【００１９】（実施例２〜11、比較例２〜11）表１に示}
^{したように実施例２〜11の合金組成に対応して、Ａ合金}
^{としてＡ１、Ａ２の組成合金をを作り、Ｂ合金としてＢ}
^{２〜Ｂ９の組成合金を作製し、以下実施例１と同様の方}
^{法で粉砕、所定の比率に混合、磁場中成形、焼結（1,05}
^{0 〜1,120 ℃×１時間）、時効処理（500 〜600 ℃×１}
^{〜10時間）を行い２合金法磁石合金Ｃ２〜Ｃ11を製造し}
^{、その磁気特性を測定して表１、２に示した。比較のた}
^{め実施例２〜11と同じ組成となる合金を１合金法により}
^{作製した以外は実施例２〜11と同条件により磁石合金Ｃ}
^{２〜Ｃ11を製造し、磁気特性を測定して比較例２〜11と}
^{し、表１、表２に示した。} ^{【００２０】} ^【表１】 ^【表２】 ^{【００２１】} ^{【発明の効果】}
^{本発明により作製した希土類永久磁石は、高価な添加元}
^{素を有効に活用して、従来法の同一組成の希土類磁石と}
^{比べて磁気特性が数段優れており、高保磁力、高残留磁}
^{束密度、さらには高エネルギー積のバランスのとれた高}
^{性能磁石を提供することが可能となった。従って今後、}
^{各種電気、電子機器用の高性能磁石として広汎に利用さ}
^{れることが期待される。} ^{Detailed Description of the Invention} ^[0001] ^{The present invention relates to various electric and electronic devices.}
^{Manufacturing method of rare earth permanent magnets with excellent magnetic properties}
^{It is about law.} ^[0002] ^{2. Description of the Related Art Among rare earth magnets, Nd-Fe-B magnets are}
^{Nd, which is the main component, is abundant in resources, low in cost, and magnetic.}
^{Due to its superiority, its use is expanding more and more in recent years.}
^{is there. Research and development for improving magnetic properties has also been carried out using Nd-based magnets.}
^{It has been energetically carried out since the early days, and many researches and inventions have been made.}
^{Is proposed. One of the manufacturing methods for Nd-based sintered magnets}
^{Two alloy powders with different compositions are mixed and sintered to obtain high}
^{Performance Nd magnet manufacturing method (hereinafter referred to as 2-alloy method)}
^{A number of inventions have been proposed regarding this.} ^{The two-alloy method proposed so far is}
^{It can be classified into three types. First person}
^{In this method, one of the raw material alloy powders to be mixed is subjected to the liquid quenching method.}
^{To produce an amorphous or fine crystal alloy,}
^{Rare earth alloy powder mixed, or both raw alloys}
^{A method in which both powders are produced and mixed by a liquid quenching method [Japanese Patent Laid-Open No. 63-9}
^{3841, JP-A-63-115307, JP-A-63-252403, JP-A-663-2}
^{78208, JP-A-1-108707, JP-A-1-146310, JP-A-1-1463}
^{09, refer to Japanese Unexamined Patent Publication No. 1-155603]. This liquid steep}
^{For the two-alloy method using alloys by the cold method, 50}
^{Reported that magnetic properties exceeding MGOe were obtained [E.Otuki, T.Otu}
^{ka and T.Imai; 11th.Int.Workshopon Rare Earth Magne}
^{ts, Pittsburgh, Pennsylvania, USA, October (1990), p.328}
^{Has been referred to].} ^{The second method is to mix two kinds of raw material alloys.}
^{R mainly for powder}2^Fe14
^{Change the type and content of rare earth elements contained as B compounds}
^{This is a method of producing the alloy and mixing and sintering it. That is, including}
^{Change the amount ratio of the Nd-rich phase or the type of rare earth element}
^{A method of mixing two kinds of the obtained alloys [JP-A-61-81603, JP-A-61-81603]}
^{61-81604, JP-A-61-81605, JP-A-61-81606, JP-A-61-81606}
^{61-81607, JP-A-61-119007, JP-A-61-20754}
^{6, see JP-A-63-245, Sho-3 and JP-A-1-177335.]}
^It ^{In the third method, one alloy is mainly used for R} 2
^Fe14
^{Alloy powder consisting of B compound and various low melting point elements}
^{, Low melting point alloys, rare earth alloys, carbides, borides, hydrides}
^{For manufacturing Nd rare earth magnets by mixing and sintering powders such as}
^{Method [JP-A-60-230959, JP-A-61-263201, JP-A-62-18140}
^{2, JP-A-62-182249, JP-A-62-206802, JP-A-62-270746,}
^{JP 63-6808, JP 63-104406, JP 63-114939, JP}
^{Sho 63-272006, JP 1-111843, JP 1-146308}
^Reference]. ^[0006] ^{Two alloys according to the prior art}
^{Method achieves the truly excellent magnetic properties of Nd-based magnet alloys}
^{There are many points that are not appropriate or insufficient for}
^{To do. That is, in the first method described above, the energy of the magnet alloy is}
^{The Gee product is high, but the coercive force is about 9 kOe, and}
^{It has a drawback that is unique to Nd magnets}
^{Is an insufficient magnet characteristic. The biggest problem is the magnetic field}
^{It is oriented. Even in the first method, the composition should be selected appropriately.}
^{Therefore, it is possible to obtain an alloy that exhibits a coercive force at room temperature.}
^{, Alloys obtained by liquid quenching method are amorphous amorphous}
^{In the magnetic field, it becomes fine powder because it becomes fine phase or fine crystals.}
^{Even if it is oriented, a certain crystal orientation should be oriented in the magnetic field direction.}
^{I can't. Therefore, the mixed raw alloy powder is}
^{The orientation of the obtained molded product is poor even after molding, and it is sufficient after sintering.}
^{It is not possible to obtain good magnet characteristics.} ^{In the second method, R in the magnet alloy is used.} 2
^Fe14^{Phase coexisting with B compound is Nd rich phase or Nd}1+
^χFeFour^BFour
^{It is a phase and neither of them exhibits magnetism at room temperature. Servant}
^{Therefore, as in the case of mixing non-magnetic compounds,}
^{Mixing of non-magnetic particles disturbs the orientation, resulting in excellent magnetic properties.}
^{I can't get a magnet. In addition, various elements as powder to be mixed}
^{And in the third method using various compounds}
^{Since the compound does not have magnetism, the demagnetizing field is generated during orientation in the magnetic field.}
^{Becomes larger, the effective magnetic field strength decreases, and}
^{The rotation of the magnetic particles in the opposite direction is insufficient, and the orientation is disturbed.} ^[0008]
^{In the third method, the powder to be mixed contains an element having a low melting point.}
^{Proposal to improve magnetic properties by using iron alloy}
^{There is a low melting point phase mixed during sintering} 2^Fe
14
^{B compounds such as lattice defects existing at grain boundaries and oxide phases}
^{Removes creation sites and cleans grain boundaries}
^{The idea is to increase the coercive force by}
^{It However, the existence of the low-melting phase is as follows.}
^{In fact, on the contrary, there are disadvantageous conditions for improving the magnetic characteristics.}
^{Has become. The low-melting phase starts to melt from around 660 ° C, for example.}
^{Therefore, at the actual sintering temperature of 1,100 ° C, the viscosity of the low melting point phase}
^{The degree will be quite small. As a result, the molded body is liquid}
^{Melt that shrinks by phase sintering and simultaneously surrounds the periphery of grains}
^{Since the viscosity of the magnetic particles is small, the magnetic particles easily rotate and}
^{The magnetic properties are deteriorated due to disordered orientation. That is, the liquid phase of the Nd magnet}
^{Desirable liquid phase component in sintering should maintain proper viscosity.}
^{The orientation of the particles is not disturbed and the compact is densified,}
^{Is required to be fully cleaned up.}
^{It In the conventional two-alloy method, the magnetism involving the liquid phase component}
^{Carefully consider both the roles of field orientation and coercive force improvement.}
^{Magnetic properties and melting points of liquid phase alloy components so that these are optimal conditions.}
^{Was not properly adjusted. The present invention is based on the two-alloy method.}
^{The above-mentioned drawbacks are improved and a well-balanced magnetism is obtained.}
^{Let's provide a manufacturing method of rare earth permanent magnets with excellent vapor characteristics}
^{It is what} ^[0009] ^{[Means for Solving the Problems]}
^{In order to solve the problem, we basically reviewed the two-alloy method,}
^{By properly selecting and combining the types and characteristics of constituent phases}
^{Well-balanced magnetic properties can be obtained}
^{Found that, completed the present invention by examining the manufacturing conditions in detail}
^{Let The gist of the present invention is that the alloy is mainly R} 2^Fe14
^{Phase B (where R is at least 1 mainly composed of Nd, Pr and Dy)}
^{An alloy consisting of one or more kinds of rare earth elements), and B alloy}
^{Contains R, Co, Fe, B, Ga, and is a constituent phase in the alloy.}
^R2^T ¹14
^{B phase and / or R rich phase (where R is the same as above)}
^{T, T} ¹ Represents a transition metal element mainly composed of Fe and Co)
Every RT²Four^{L phase, RT} ²3^{Phase, RT} ²2^{Phase, R}2^T ²7
^{Phase and RT} ²Five^{Phase (where R is the same as above, T} ² Is Fe, C
Transition metal elements mainly composed of o, the same transition metals and Ga and B
1 or 2 of these, L represents B or B and Ga) 5
Alloy consisting of one phase or a mixed phase with two or more phases
And 1 part of B alloy powder to 99 to 70% by weight of A alloy powder
-30% by weight, and press molding the mixed alloy powder in a magnetic field
And sinter the compact in a vacuum or an inert gas atmosphere.
In addition, the aging heat treatment should be performed at a temperature lower than the sintering temperature.
A method for producing a rare earth permanent magnet, which is characterized by further details.
Ku, RT included in B alloy²Four^{L phase, RT} ²3^{Phase, RT} ²2
^{Phase, R}2^T ²7^{Phase and RT} ²Five
^{The melting point of at least one of the five constituent phases of the phase}
^{It is an intermetallic compound with a temperature of 700 ℃ or more and 1,155 ℃ or less.}
^{At least one phase has a Curie temperature above room temperature}
^{Is a magnetic substance that has at least one phase at room temperature or higher.}
^{With Curie temperature and crystalline magnetic anisotropy}
^{A method of manufacturing a rare earth magnet characterized by being a body}
^. ^{The present invention will be described in detail below. The present invention is}
^{Rare earth permanent magnet called so-called two-alloy method (hereinafter, magnet alloy C}
^{That is, the production method is}
^R 2^Fe14
^{La, Ce, Pr, Nd, Pm, Sm consisting of B compound phase and R containing Y}
^{, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu selected Nd, P}
^{At least one kind of rare earth element mainly composed of r and Dy}
^{is there. For alloy A, raw metal is vacuum or inert gas, preferably}
^{It is preferably melted and cast in Ar atmosphere. Raw metal is pure rare earth}
^{Uses elemental elements, pure iron, ferroboron, etc.}
^{Including a trace amount of impurities that are inevitable in industrial production}
^{To do. The obtained ingot is R}2^Fe14
^{B phase is formed by peritectic reaction between αFe and rare earth rich phase}
^{Therefore, the αFe phase and R}
^{The H-phase or B-rich phase may remain. Book}
^{In the invention, R in A alloy}2^Fe14
^{Since it is desirable to have a large amount of phase B, solution treatment may be performed if necessary.}
^{Do the work. The conditions are 700 to 1, under vacuum or Ar atmosphere.}
^{The heat treatment may be performed in the temperature range of 200 ° C for 1 hour or more.} ^{Is the B alloy mainly R, Co, Fe, B and Ga?}
^{Alloy consisting of} a^Feb^Coc^Bd^Gae
^{(Where R is Y including La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb}
^{, Dy, Ho, Er, Tm, Yb and Lu selected from Nd, Pr, Dy}
^{At least one or more rare earth elements forming the body, 15 ≦ a ≦ 40}
^{, 0 ≤ b ≤ 80, 5 ≤ c ≤ 85, 0 ≤ d ≤ 20, 0.1 ≤ e ≤ 20, a}
^{+ b + c + d + e = 100}
^{(Each atom%)).}
^{Melts in vacuum or in an inert gas, preferably Ar atmosphere}
^{To cast. Raw metals include pure rare earth elements, pure iron and pure copper.}
^{Use baltic, pure gallium, ferroboron, etc.}
^{Contains trace impurities inevitable in general industrial production}
^{I shall. If the content a of rare earth element R is less than 15 atom%, R}
^{Is too small, there is a sufficient amount of liquid phase in the sintering process.}
^{Was not obtained, the density of the sintered body did not rise, and 40 atom%}
^{If it exceeds, the melting point of the alloy will become too low and the magnetic properties will be improved.}
^{There is no end. RT when the amount c of Co is less than 5 atomic%} ²Four
^{L phase, RT} ²3^{Phase, RT} ²2^{Phase, R}2^T ²7^{Phase and RT} ²Five
^{Each phase such as phase disappears, and the effect of improving magnetic properties is obtained.}
^{I can't. When the content d of Ga exceeds 20 atomic%, the saturation magnetism of the alloy is increased.}
^{The bundle density becomes small and high magnetic properties cannot be obtained. Also,}
^{Even if the ribbon obtained by the liquid quenching method is heat-treated, the B alloy}
^{Can be produced. That is, in the liquid quenching method,}
^{After quenching, B alloy becomes amorphous phase or fine crystalline phase.}
^{It is heated at a temperature above the crystallization temperature for a certain period of time.}
^{When heated, it causes crystallization or recrystallization and}
^{It is possible to precipitate a predetermined light constituent phase.} ^{Appearing mainly in B alloy in this composition range}
^{The phase to do is R} 2^T ¹14^{Phase B (mainly R}2^Fe14
^{B phase), R rich phase (where R is the same as above, T} ¹ Is F
e represents a transition metal element mainly composed of Co) and RT²Four
^{L phase, RT} ²3^{Phase, RT} ²2^{Phase, R}2^T ²7^{Phase and RT} ²Five
^{Phase (where R is the same as above, T} ² Is mainly Fe, Co
A transition metal element, one of the transition metals and Ga and B, or
Two types, L represents B or B and Ga), etc.
Is at least one or two or more of the front two phases and the rear five phases
It is characterized by using B alloy containing the above phases. Note that
The R-rich phase has a R content of 35 atomic% or more.
It represents all of the various R-rich phases. These 7
R of the phases₂ Fe₁₄Two phases, B phase and R rich phase,
Conventionally known two-alloy method and ordinary rare earth iron boron magnet combination
It is a phase that has also appeared due to the manufacturing method of gold. The rest of R
T²Four^{L phase, RT} ²3^{Phase, RT} ²2^{Phase, R}2^T ²7^{Phase, RT} ²Five
^{Five types of phases are added to the B alloy with Co of 5 atomic% or more.}
^{Which is unique to the two-alloy method of the present invention.}
^{It is a thing. For these five phases, Co should be added in an amount of 5 atomic% or more.}
^By
^{It first appeared as an equilibrium phase in B alloy. Figure}
^{1 is a scanning electron microscope showing a photograph of the cast structure of the B alloy of the present invention.}
^{Photographed and EPMA (electron probe X-ray micro}
^{Nalizer) and X-ray analysis in one case RT}
²Four^{L phase, RT} ²3^{Phase, RT} ²2
^{The existence of the phase and the R-rich phase is clearly shown. The present invention}
^{The two-alloy method by}
^{The presence of at least one of these phases, characterized by the inclusion of at least one}
^{Magnetic properties of magnet alloys produced by the two-alloy method by}
^{Could be realized.} ^{In the present invention, the A alloy and B alloy described above are special}
^{The magnet alloy C is produced by the so-called two-alloy method by mixing in a fixed ratio.}
^{It was manufactured and was able to exhibit high magnetic properties. Less than,}
^{The presence of these mixed phases in the B alloy is due to the high magnetism of the magnet alloy.}
^{The reason why the qi characteristics are brought about will be described. First the first reason}
^{The reason is that these mixed phases have a Curie temperature above room temperature.}
^{To have, which is achieved by the additive element Co}
^{It was Furthermore, these phases are crystalline magnetic in a specific crystallographic direction.}
^{Has anisotropy. Therefore, of these phases as the main constituent phases}
^{Mainly R alloy containing B alloy powder containing one or more kinds} 2^Fe14
^{Oriented in a magnetic field by mixing with A alloy powder consisting of B phase}
^{, And B alloy is also a ferromagnetic material and has magnetic anisotropy.}
^{Almost all particles are oriented with their crystal directions aligned in the magnetic field direction,}
^{High magnetic characteristics can be obtained.} ^{The second reason is that the melting points of these phases are Nd rare metals.}
^{Suitable temperature range for liquid phase sintering of earth magnets, ie 700}
^{It should be in the range of ℃ to 1,155 ℃. This temperature}
^{The range is higher than the melting point of Nd-rich phase (500-650 ℃),}
^{Moreover, R} 2^Fe14
^{The temperature is lower than the melting point of phase B (1,155 ° C). Therefore,}
^{Only Nd-rich phase is present at normal sintering temperature}
^{The melt viscosity becomes too low, which results in particle orientation.}
^{It does not disturb the}
^{And increase the density while cleaning the grain boundaries, and high after sintering}
^{The magnet characteristics will be realized. Another by adding Co}
^{The effect of is that the corrosion resistance is improved. B alloy is A}
^{Since it contains more rare earth elements than alloys, it is prone to oxidative deterioration}
^{However, adding Co prevents oxidative deterioration}
^{It is possible to obtain stable magnetic characteristics. Added to B alloy}
^{A large amount of added Dy and Ga exist near the grain boundaries even after both are sintered.}
^{However, it has an effect of improving the coercive force of the magnet alloy C.} ^{Next, a method for producing a magnet alloy C by the two-alloy method}
^{State. A alloy and B alloy obtained as described above}
^{Gold is crushed separately from each ingot and then mixed in a specified proportion.}
^{Are combined. The crushing is performed by wet or dry crushing. Rare}
^{Earth alloys are very active and prevent oxidation during grinding}
^{For dry crushing, in an atmosphere of Ar or nitrogen, etc.}
^{In case of wet grinding, non-reactive organic solvent such as CFC}
^{Done in. The mixing process may also be performed in an inert atmosphere or as needed.}
^{Is carried out in a solvent. Grinding is generally coarse grinding, fine grinding and step grinding.}
^{Mixing can be done at any stage, although it is done hierarchically.}
^{That is, even if a predetermined amount is mixed after coarse pulverization and then fine pulverization is performed.}
^{Well, after all the grinding is completed}
^{May be. Both A and B alloys are mixed uniformly with almost the same average grain size.}
^{The average particle size is in the range of 0.5 to 20 μm.}
^{Is less than 0.5 μm, it easily oxidizes and deteriorates.}
^{If it exceeds, the sinterability will deteriorate.} ^{The mixing ratio of the A alloy powder and the B alloy powder is A}
^{1 to 30 weight% of B alloy powder for 99 to 70 weight% of alloy powder}
^{It is better to mix in the range of 10%, and if the B alloy powder is less than 1% by weight.}
^{If it is full, the sintered density will not increase and coercive force will not be obtained.}
^{%, The proportion of non-magnetic phase after sintering becomes large.}
^{And the residual magnetic flux density becomes small. Got}
^{The mixed fine powder of the A alloy and the B alloy thus prepared is then subjected to a molding pretreatment in a magnetic field.}
^{Molded to the desired size and then sintered and heat treated.}
^{It Sintering is performed in vacuum or argon in the temperature range of 900 to 1,200 ° C.}
^{For 30 minutes or more, and}
^{Aging heat treatment at low temperature for 30 minutes or more. After sintering, the magnet alloy C}
^{The density of the compact is 95% or more in terms of the true density ratio.}
^{A high residual magnetic flux density can be obtained.} ^[0017] ^{EXAMPLES Specific embodiments of the present invention will be described below.}
^{The present invention is described below.}
^{It is not limited to these.} ^{(Example 1, Comparative Example 1) Nd, Fe metal having a purity of 99.9% by weight}
^{And ferroboron are used to formulate 12.5Nd-6B-81.5Fe (}
^{% Alloy) by melting casting in an Ar atmosphere of a high frequency melting furnace}
^{After fabrication, this ingot is heated at 1,070 ℃ in Ar atmosphere.}
^{Solution-ized for 20 hours. This is an A1 alloy. Then the same}
^{99.9% by weight of Nd, Dy, Fe, Ga, Co metals and ferroboro}
^{Alloy of composition formula 20Nd-10Dy-20Fe-6B-4Ga-40Co}
^{Using a high-frequency melting furnace, melt casting in an Ar atmosphere,}
^{1 alloy. A1 alloy ingot and B1 alloy ingot}
^{Each of them is crushed separately in a nitrogen atmosphere and crushed into 30 mesh.}
^{Less than 100% by weight, then add 90% by weight of A1 alloy coarse powder to B1 alloy coarse powder.}
^{10% by weight of the powder was weighed and placed in a nitrogen-displaced V blender.}
^{Mix for 30 minutes. This mixed coarse powder is used with high pressure nitrogen gas.}
^{It was finely pulverized with a jet mill to an average particle size of about 5 μm.}
^{While orienting the obtained mixed fine powder in a magnetic field of 15 kOe}
^{, About 1Ton / cm} ² It was press molded under the pressure of. Then this
The compact was sintered in an Ar atmosphere sintering furnace at 1,070 ° C for 1 hour.
And aging heat treatment at 530 ℃ for 1 hour and quenching
Alloy C1 was prepared. For comparison, an alloy having the same composition as in Example 1
Was manufactured by the conventional 1-alloy method, and was designated as Comparative Example 1. That is,
The same composition (magnet alloy C1) after mixing both A1 and B1 alloys
Weigh from the beginning, melt, crush, sinter, heat treat with aging 2
The magnet by the alloy method (magnet composition C1 of Example 1) and magnetic characteristics
Sex was compared. The composition of this magnet alloy C1 is based on the two-alloy method.
In both Example 1 and Comparative Example 1 by the alloy method, 13.1 Nd-
It is 0.8Dy-3.5Co-6.0B--0.3Ga-76.6Fe. Implemented in Table 1
The magnetic characteristics obtained in both the sintered magnets of Example 1 and Comparative Example 1
The property value and the sintered body density are shown. Comparison of the magnetic properties of Example 1
Compared with Example 1, the sintered body density is almost the same, but
For all values such as magnetic flux density, coercive force, maximum energy product, etc.
Therefore, Example 1 is greatly superior. Thus magnet alloy
Even if the composition of C is exactly the same, a considerable difference occurs in the magnetic characteristics.
The two-alloy method is extremely effective for improving the magnetic properties of Nd magnets.
It is an effective method. Casting of B1 alloy
The metallographic structure in the state is shown in Fig. 1.
It is shown by a picture photograph. As you can see from the light and dark in the photo, B1
There are four main constituent phases in gold. Each phase is EPMA (electronic
Probe X-ray microanalyzer) and X-ray analysis
Then, as shown in the figure, RT²Four^{L phase, RT} ²3^{Phase, RT} ²2
^{Phase and R-rich phase.} ^{(Examples 2 to 11, Comparative Examples 2 to 11)}
^{As described above, corresponding to the alloy compositions of Examples 2 to 11, the A alloy}
^{As a composition alloy of A1 and A2,}
^{2 to B9 composition alloys were prepared and the same method as in Example 1 was performed.}
^{Crushed by a method, mixed in a predetermined ratio, molded in a magnetic field, sintered (1,05}
^{0 to 1,120 ° C x 1 hour, aging treatment (500 to 600 ° C x 1)}
^{~ 10 hours) to produce the two-alloy method magnet alloys C2 to C11}
^{The magnetic properties were measured and shown in Tables 1 and 2. Comparison}
^{Therefore, an alloy having the same composition as in Examples 2 to 11 was prepared by the 1-alloy method.}
^{Magnet alloy C under the same conditions as in Examples 2 to 11 except that it was manufactured.}
^{2 to C11 were manufactured, and the magnetic characteristics were measured to obtain Comparative Examples 2 to 11.}
^{The results are shown in Tables 1 and 2.} ^[0020] ^{[Table 1]} ^{[Table 2]} ^[0021] ^{【The invention's effect】}
^{The rare earth permanent magnet produced by the present invention is an expensive additive source.}
^{By effectively utilizing the element, the rare earth magnet with the same composition of the conventional method}
^{Magnetic properties are several orders of magnitude better than other products, and high coercive force and high remanence}
^{Balanced high of flux density and even high energy product}
^{It has become possible to provide high performance magnets. Therefore, in the future,}
^{Widely used as a high-performance magnet for various electric and electronic devices.}
^{Expected to be}

^{【図面の簡単な説明】} ^{【図１】実施例１のＢ１合金の鋳造状態での金属組織を}
^{示す走査電子顕微鏡写真である。} ^{【符号の説明】} ^ＲＴ ²4^Ｌ相 ^ＲＴ ² 3^相 ^ＲＴ ² 2^相 ^{Ｒリッチ相} ^{BRIEF DESCRIPTION OF THE DRAWINGS} ^{FIG. 1 shows the metallurgical structure of the B1 alloy of Example 1 in the cast state.}
^{It is a scanning electron micrograph shown.} ^{[Explanation of symbols]} ^RT ² 4 ^{L phase} ^RT ² 3 ^phase ^RT ² 2 ^phase ^{R rich phase}

─────────────────────────────────────────────────────
【手続補正書】【提出日】平成３年７月１２日【手続補正１】【補正対象書類名】明細書【補正対象項目名】０００６【補正方法】変更【補正内容】【０００６】【発明が解決しようとする課題】従来技術による２合金
法ではＮｄ系磁石合金の真に優れた磁気特性を実現させ
るのに適切でなかったり不充分だったりする点が多く存
在する。即ち、前述した第１の方法では磁石合金のエネ
ルギー積は高いが保磁力は約９_ｋ０_ｅ程度で、温度上昇
によって保磁力が低下するというＮｄ磁石特有の欠点の
ために、実用的には不充分な磁石特性である。最も大き
な問題点は、磁場配向性である。第１の方法でも組成を
適当に選ぶことによって、室温で磁性を示す合金を得る
ことができるが、液体急冷法によって得られる合金は非
晶質アモルファス相あるいは微細結晶となるため、微粉
にして磁場中で配向させても特定の結晶方位を磁場方向
に配向させることができない。従って、混合した原料合
金粉体を磁場中成形しても得られる成形体の配向性は悪
く、焼結後充分な磁石特性が得られないことになる。【手続補正２】【補正対象書類名】明細書【補正対象項目名】０００７【補正方法】変更【補正内容】【０００７】第２の方法においては、磁石合金中のＲ_２
Ｆｅ_１４Ｂ化合物と共存する相はＮｄリッチ相あるいは
Ｎｄ_１＋ＸＦｅ_４Ｂ_４相であり、この両相とも室温では
磁性を示さない。従って、磁性を持たない化合物を混合
しても非磁性粒子が配向性を乱して、磁気特性の優れた
磁石は得られない。また、混合する粉体として各種元素
や種々の化合物を用いる第３の方法においてもこれらの
化合物は磁性をもたないために、磁場中配向時に反磁場
が大きくなって有効磁場強度が減少し、そのため磁場方
向への磁性粒子の回転が不充分となって配向が乱れる。【手続補正３】【補正対象書類名】明細書【補正対象項目名】００１０【補正方法】変更【補正内容】【００１０】以下本発明を詳細に説明する。本発明は所
謂２合金法と称する希土類永久磁石（以下、磁石合金Ｃ
という）の製造方法であり、原料となるＡ合金は主とし
てＲ_２Ｆｅ_１４Ｂ化台物相からなり、ＲはＹを含むＬ
ａ，Ｃｅ，Ｐｒ，Ｎｄ，Ｐｍ，Ｓｍ，Ｅｕ，Ｇｄ，Ｔ
ｂ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，ＹｂおよびＬｕから選択
されるＮｄ，Ｐｒ，Ｄｙを主体とする少なくとも１種類
以上の希土類元素である。Ａ合金は原料金属を真空また
は不活性ガス、好ましくはＡｒ雰囲気中で溶解し鋳造す
る。原料金属は純希土類元素および希土類合金、純鉄、
フェロボロン、さらにはこれらの合金等を使用するが、
一般的な工業生産において不可避な微量不純物は含まれ
るものとする。得られたインゴットは、Ｒ_２Ｆｅ_１４Ｂ
相がаＦｅと希土類リッチ相との包晶反応によって形成
されるため、鋳造後も凝固偏析によってаＦｅ相、Ｒリ
ッチ相、あるいはＢリッチ相等が残留する場合がある。
本発明においてはＡ合金中のＲ_２Ｆｅ_１４Ｂ相が多いほ
うが望ましいので、必要に応じて溶体化処理を行う。そ
の条件は真空またはＡｒ雰囲気下、７００〜１，２００
℃の温度領域で１時間以上熱処理すれば良い。【手続補正４】【補正対象書類名】明細書【補正対象項目名】００１１【補正方法】変更【補正内容】【００１１】Ｂ合金は主としてＲ，Ｃｏ，Ｆｅ、Ｂおよ
びＧａから成る合金で、組成式Ｒ_ａＦｅ_ｂＣｏ_ｃＢ_ｄＧ
ａ_ｅ（ここにＲは、Ｙを含むＬａ，Ｃｅ，Ｐｒ，Ｎｄ，
Ｐｍ，Ｓｍ，Ｅｕ，Ｇｄ，Ｔｂ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔ
ｍ，ＹｂおよびＬｕから選択されるＮｄ，Ｐｒ，Ｄｙを
主体とする少なくとも１種以上の希土類元素、１５≦ａ
≦４０、０≦ｂ≦８０、５≦ｃ≦８５、０≦ｄ≦２０、
０．１≦ｅ≦２０、ａ＋ｂ＋ｃ＋ｄ＋ｅ＝１００（各原
子％））で表わされ、Ａ合金と同様に原料金属を真空ま
たは不活性ガス、好ましくはＡｒ雰囲気中で溶解し鋳造
する。原料金属としては純希土類元素、および希土類合
金、純鉄、純コバルト、純ガリウム、フェロボロン、さ
らにはこれらの合金等を使用するが、一般的な工業生産
において不可避な微量不純物は含まれるものとする。希
土類元素Ｒの量ａが１５原子％未満ではＲが少な過ぎる
ために焼結工程において十分な量の液相が得られず、焼
結体の密度が上がらなくなり、４０原子％を越えると合
金の融点が低くなり過ぎて磁気特性の向上効果がなくな
る。Ｃｏの量ｃが５原子％未満ではＲＴ^２ _４Ｌ相、ＲＴ
^２ _３相、ＲＴ^２ _２相、Ｒ_２Ｔ^２ _７相およびＲＴ^２ _５相等
の各相が出現しなくなり、磁気特性の向上効果が得られ
ない。Ｇａの量ｄが２０原子％を越えると合金の飽和磁
束密度が小さくなり高い磁気特性が得られない。また、
液体急冷法によって得られた薄帯を熱処理してもＢ合金
を作製することができる。即ち、液体急冷法において、
急冷後のＢ合金はアモルファス相或は微細結晶相となっ
ており、これを結晶化温度以上の温度で一定時間以上加
熱することにより、結晶化或は再結晶成長させて、本発
明の所定の構成相を析出させることが出来る。 ─────────────────────────────────────────────────────
【手続補正書】【提出日】平成４年７月１０日【手続補正１】【補正対象書類名】明細書【補正対象項目名】０００３【補正方法】変更【補正内容】【０００３】これまでに提案されている２合金法を大き
く分けると、３種類に分類することができる。第１の方
法は、混合する原料合金粉体の一方を液体急冷法によっ
て非晶質あるいは微細結晶合金を作製し、それに通常の
希土類合金粉末を混合するか、あるいは両方の原料合金
粉体を共に液体急冷法で作製混合する方法［特開昭63-9
3841、特開昭63-115307、特開昭63-252403、特開昭63-278
208、特開平1-108707、特開平1-146310、特開平1-146309、
特開平1-155603各号公報参照］である。この液体急冷
法による合金を使用する２合金法については、最近50MG
Oeを越える磁気特性が得られたと報告[E.Otuki,T.Otuka
and T.Imai;11th.Int.Workshop on Rare Earth Magnet
s,Pittsburgh,Pennsylvania,USA,October(1990),p.328
参照 ]されている。【手続補正２】【補正対象書類名】明細書【補正対象項目名】０００４【補正方法】変更【補正内容】【０００４】第２の方法は、混合する２種類の原料合金
粉体を共に主としてＲ₂ Fe₁₄Ｂ化合物とし含有される希
土類元素の種類、含有量を変えた合金を作製して混合焼
結する方法である。即ち、含有するNdリッチ相の量比あ
るいは希土類元素の種類を変えた合金を２種類混合する
方法［特開昭61-81603、特開昭61-81604、特開昭61-816
05、特開昭61-81606、特開昭61-81607、特開昭61-11900
7、特開昭61-207546、特開昭63-245903、特開平1-177335各
号公報参照］である。【手続補正３】【補正対象書類名】明細書【補正対象項目名】００１１【補正方法】変更【補正内容】【００１１】Ｂ合金は主としてＲ、Co、Fe、ＢおよびGaか
ら成る合金で、組成式Ｒ_aFe_bCo_c Ｂ_d Ga_e （ここにＲ
は、Ｙを含む La,Ce,Pr,Nd,Pm,Sm,Eu,Gd,Tb,Dy,Ho,Er,T
m,YbおよびLuから選択されるNd、Pr、Dyを主体とする少な
くとも１種以上の希土類元素、15≦a ≦40、０≦b ≦8
0、５≦c ≦85、０≦d ≦20、0.1≦e ≦20、a+b+c+d+e=10
0(各原子％) ）で表わされ、Ａ合金と同様に原料金属を
真空または不活性ガス、好ましくはAr雰囲気中で溶解し
鋳造する。原料金属としては純希土類元素、純鉄、純コ
バルト、純ガリウム、フェロボロン等を使用するが、一
般的な工業生産において不可避な微量不純物は含まれる
ものとする。希土類元素Ｒの量a が15原子％未満ではＲ
が少な過ぎるために焼結工程において十分な量の液相が
得られず、焼結体の密度が上がらなくなり、40原子％を
越えると合金の融点が低くなり過ぎて磁気特性の向上効
果がなくなる。Coの量c が５原子％未満ではＲＴ² ₄Ｌ
相、ＲＴ² ₃相、ＲＴ² ₂相、Ｒ₂ Ｔ² ₇相およびＲＴ² ₅相等
の各相が出現しなくなり、磁気特性の向上効果が得られ
ない。Gaの量ｅが20原子％を越えると合金の飽和磁束密
度が小さくなり高い磁気特性が得られない。また、液体
急冷法によって得られた薄帯を熱処理してもＢ合金を作
製することができる。即ち、液体急冷法において、急冷
後のＢ合金はアモルファス相或は微細結晶相となってお
り、これを結晶化温度以上の温度で一定時間以上加熱す
ることにより、結晶化或は再結晶成長させて、本発明の
所定の構成相を析出させることが出来る。─────────────────────────────────────────────────── ───
[Procedure Amendment] [Date of submission] July 12, 1991 [Procedure Amendment 1] [Document name for amendment] Specification [Item name for amendment] 0006 [Correction method] Change [Correction content] [0006] [Invention However, there are many points that the two-alloy method according to the prior art is not appropriate or insufficient for realizing the truly excellent magnetic characteristics of the Nd-based magnet alloy. That is, the first energy product is high coercivity of the magnet alloy in the method about 9 _k 0 _e described above, the Nd magnet specific drawbacks that the coercive force is lowered by the temperature rise
For practical a magnet properties insufficient to. The biggest problem is magnetic field orientation. Even in the first method, an alloy exhibiting magnetism at room temperature can be obtained by appropriately selecting the composition. However, since the alloy obtained by the liquid quenching method becomes an amorphous amorphous phase or fine crystals, it is made into a fine powder and a magnetic field. Even if it is oriented inside, a specific crystal orientation cannot be oriented in the magnetic field direction. Therefore, even if the mixed raw material alloy powder is molded in a magnetic field, the resulting molded body has poor orientation, and sufficient magnet characteristics cannot be obtained after sintering. [Procedure Amendment 2] [Name of Document to Amend] Specification [Name of Item to Amend] 0007 [Correction Method] Change [Content of Amendment] In the second method, R ₂ in the magnet alloy is used.
The phase coexisting with the Fe ₁₄ B compound is the Nd rich phase or the Nd ₁₊ XFe ₄ B ₄ phase, and neither of these phases exhibits magnetism at room temperature. Therefore, mix compounds without magnetism
Even disturbs the orientation of the non-magnetic particles child by not obtained excellent magnet magnetic properties. Further, even in the third method in which various elements and various compounds are used as the powder to be mixed, since these compounds do not have magnetism, the demagnetizing field becomes large during the orientation in the magnetic field and the effective magnetic field strength decreases, Therefore, the rotation of the magnetic particles in the magnetic field direction is insufficient and the orientation is disturbed. [Procedure Amendment 3] [Document Name of Amendment] Specification [Name of Item Amendment] 0010 [Method of Amendment] Change [Content of Amendment] [0010] The present invention will be described in detail below. The present invention is a so-called two-alloy method, which is a rare earth permanent magnet (hereinafter referred to as magnet alloy C).
That is, the A alloy as a raw material is mainly composed of a R ₂ Fe ₁₄ B-comprising polyhedral phase, and R is L containing Y.
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
It is at least one kind of rare earth element mainly composed of Nd, Pr and Dy selected from b, Dy, Ho, Er, Tm, Yb and Lu. The alloy A is cast by melting the raw material metal in a vacuum or an inert gas, preferably Ar atmosphere. Raw metals are pure rare earth elements and rare earth alloys , pure iron,
Ferroboron, and even these alloys are used,
Trace impurities that are inevitable in general industrial production shall be included. The obtained ingot is R ₂ Fe ₁₄ B
Since the phase is formed by the peritectic reaction between аFe and the rare earth-rich phase, the аFe phase, the R-rich phase, the B-rich phase, etc. may remain after the casting due to solidification segregation.
In the present invention, since it is desirable that the amount of R ₂ Fe ₁₄ B phase in the A alloy is large, solution treatment is performed if necessary. The conditions are 700 to 1,200 under vacuum or Ar atmosphere.
It suffices to perform heat treatment for 1 hour or more in the temperature range of ° C. [Procedure Amendment 4] [Amendment Document Name] Specification [Amendment Item Name] 0011 [Amendment Method] Change [Amendment Content] B alloy is an alloy mainly composed of R, Co, Fe, B and Ga. Compositional formula R _a Fe _b Co _c B _d G
a _e (where R is Y, including La, Ce, Pr, Nd,
Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
at least one or more rare earth elements mainly composed of Nd, Pr and Dy selected from m, Yb and Lu, 15 ≦ a
≦ 40, 0 ≦ b ≦ 80, 5 ≦ c ≦ 85, 0 ≦ d ≦ 20,
0.1 ≦ e ≦ 20, a + b + c + d + e = 100 (each atomic%)), and the raw material metal is melted and cast in a vacuum or an inert gas, preferably Ar atmosphere, like the A alloy. Pure rare earth elements and rare earth compounds
Gold, pure iron, pure cobalt, pure gallium, ferroboron, is
These alloys and the like are used for these, but trace amounts of impurities that are inevitable in general industrial production are included. If the amount a of the rare earth element R is less than 15 atomic%, the amount R is too small to obtain a sufficient amount of liquid phase in the sintering process, and the density of the sintered body cannot be increased. The melting point becomes too low, and the effect of improving magnetic properties is lost. When the amount c of Co is less than 5 atomic%, RT ² ₄ L phase, RT
Each of the phases such as the ² ₃ phase, the RT ² ₂ phase, the R ₂ T ² ₇ phase and the RT ² ₅ phase does not appear, and the effect of improving the magnetic characteristics cannot be obtained. When the amount d of Ga exceeds 20 atomic%, the saturation magnetic flux density of the alloy becomes small and high magnetic properties cannot be obtained. Also,
The B alloy can also be produced by heat-treating the ribbon obtained by the liquid quenching method. That is, in the liquid quenching method,
After being rapidly cooled, the B alloy is in an amorphous phase or a fine crystalline phase. By heating the B alloy at a temperature equal to or higher than the crystallization temperature for a certain period of time, crystallization or recrystallization is performed, and the predetermined amount of the present invention is obtained. The constituent phases can be precipitated. ─────────────────────────────────────────────────── ───
[Procedure amendment] [Date of submission] July 10, 1992 [Procedure Amendment 1] [Document name for amendment] Specification [Item name for amendment] 0003 [Correction method] Change [Content of amendment] [0003] Until now The two-alloy method proposed in (1) can be roughly classified into three types. The first method is to prepare an amorphous or fine crystal alloy by liquid quenching one of the raw material alloy powders to be mixed, and mix it with a normal rare earth alloy powder, or to mix both raw material alloy powders together. Method of preparing and mixing by liquid quenching method [Japanese Patent Laid-Open No. 63-9
3841, JP 63-115307, JP 63-252403, JP Akira 63 -278
208, JP-A-1-108707, JP-A-1-146310, JP-A-1-146309,
See Japanese Patent Laid-Open No. 1-155603]. Regarding the two-alloy method using the alloy by this liquid quenching method, recently, 50MG
Reported that magnetic properties exceeding Oe were obtained [E.Otuki, T.Otuka
and T.Imai; 11th.Int.Workshop on Rare Earth Magnet
s, Pittsburgh, Pennsylvania, USA, October (1990), p.328
Has been referred to]. [Procedure Amendment 2] [Document name to be amended] Specification [Item name to be amended] 0004 [Correction method] Change [Details of amendment] The second method is to mainly mix two kinds of raw material alloy powders to be mixed. This is a method in which alloys having different kinds and contents of rare earth elements contained as R ₂ Fe ₁₄ B compounds are produced and mixed and sintered. That is, a method of mixing two kinds of alloys in which the amount ratio of the contained Nd-rich phase or the kind of rare earth element is changed [JP-A-61-81603, JP-A-61-81604, and JP-A-61-816].
05, JP 61-81606, JP 61-81607, JP 61-11900
7, JP 61-207546, JP 63-245 90 3, Hei 1-177335 is the JP reference. [Procedure Amendment 3] [Amendment Document Name] Specification [Amendment Item Name] 0011 [Amendment Method] Change [Amendment Content] B alloy is an alloy mainly composed of R, Co, Fe, B and Ga. Compositional formula R _a Fe _b Co _c B _d Ga _e (where R
Is Y, including La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
at least one or more rare earth elements mainly composed of Nd, Pr and Dy selected from m, Yb and Lu, 15 ≦ a ≦ 40, 0 ≦ b ≦ 8
0, 5 ≤ c ≤ 85, 0 ≤ d ≤ 20, 0.1 ≤ e ≤ 20, a + b + c + d + e = 10
0 (each atomic%)), and the raw material metal is melted and cast in a vacuum or an inert gas, preferably Ar atmosphere, like the A alloy. Although pure rare earth elements, pure iron, pure cobalt, pure gallium, ferroboron, etc. are used as the raw material metal, trace impurities that are inevitable in general industrial production are included. If the content a of rare earth element R is less than 15 atom%, R
Since the amount is too small, a sufficient amount of liquid phase cannot be obtained in the sintering process, the density of the sintered body cannot be increased, and when it exceeds 40 atomic%, the melting point of the alloy becomes too low and the effect of improving magnetic properties is lost. . RT ² ₄ L when the amount c of Co is less than 5 atomic%
Phase, RT ² ₃ phase, RT ² ₂ phase, R ₂ T ² ₇ phase, RT ² ₅ phase, etc. do not appear, and the effect of improving magnetic properties cannot be obtained. When the amount e of Ga exceeds 20 atomic%, the saturation magnetic flux density of the alloy becomes small and high magnetic properties cannot be obtained. Further, the B alloy can be produced by heat-treating the ribbon obtained by the liquid quenching method. That is, in the liquid quenching method, the B alloy after quenching has an amorphous phase or a fine crystalline phase, and by heating this at a temperature not lower than the crystallization temperature for a certain time or more, crystallization or recrystallization growth is caused. Thus, the predetermined constituent phase of the present invention can be precipitated.

Claims

Claims: 1. A alloy mainly composed of R ₂ Fe ₁₄ B phase (where R
Is an alloy composed of at least one or more rare earth elements mainly composed of Nd, Pr and Dy, and B alloy is R, Co, Fe,
R ₂ T ¹ 14 containing B and Ga as a constituent phase in the alloy
^{B phase and / or R rich phase (where R is the same as above)}
^(T ¹ represents a transition metal element mainly composed of Fe and Co), and RT ² 4 ^{L phase, RT} ² 3 ^{phase, RT} ² 2 ^{phase, R} 2 ^T ² 7
^{Phase and RT} ² 5 ^{phase (here R is as defined above, T} ² is Fe, C
Transition metal elements mainly composed of o, the same transition metals and Ga and B
1 or 2 of these, L represents B or B and Ga) 5
An alloy consisting of one or a mixture of two or more phases of the phases, and the B alloy powder is 1 to 99% to 70% by weight of the A alloy powder.
-30% by weight, the mixed alloy powder is pressure-molded in a magnetic field, the compact is sintered in a vacuum or an inert gas atmosphere, and further subjected to an aging heat treatment at a low temperature equal to or lower than the sintering temperature. A method for manufacturing a rare earth permanent magnet. 2. RT ² 4 contained in the B alloy according to claim 1.
^{L-phase, RT} ² ^{3-phase, RT} ² ^{2-phase, R} ² ^T 2 7 ^{phase and RT} ² 5
^{The melting point of at least one of the five constituent phases of the phase}
^{It must be an intermetallic compound of 700 ℃ or more and 1,155 ℃ or less}
^{A method for producing a rare earth permanent magnet, characterized by:} ^{3. The B alloy according to claim 1 or 2.}
^{Out of the five constituent phases, at least one or more phases are at room temperature or above.}
^{Characterized by being a magnetic material having a Curie temperature above}
^{A method for manufacturing a rare earth magnet.} ^{4. The B alloy according to claim 1, 2 or 3.}
^{Of at least one of the five constituent phases contained in}
^{Has a Curie temperature above room temperature and magnetocrystalline anisotropy.}
^{Of rare earth magnets characterized by having a magnetic substance}
^Method. ^{5. The A alloy, B alloy and A according to claim 1.}
^{When the average particle size of the B mixed alloy powder is within the range of 0.5 to 20 μm}
^{A method for manufacturing a rare earth magnet, characterized by being present.}