JPH0545045B2 - - Google Patents

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Publication number
JPH0545045B2
JPH0545045B2 JP60200890A JP20089085A JPH0545045B2 JP H0545045 B2 JPH0545045 B2 JP H0545045B2 JP 60200890 A JP60200890 A JP 60200890A JP 20089085 A JP20089085 A JP 20089085A JP H0545045 B2 JPH0545045 B2 JP H0545045B2
Authority
JP
Japan
Prior art keywords
permanent magnet
less
thin film
atomic
magnet
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 - Lifetime
Application number
JP60200890A
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Japanese (ja)
Other versions
JPS6260212A (en
Inventor
Shigeki Hamada
Tetsuharu Hayakawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Proterial Ltd
Original Assignee
Sumitomo Special Metals Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sumitomo Special Metals Co Ltd filed Critical Sumitomo Special Metals Co Ltd
Priority to JP60200890A priority Critical patent/JPS6260212A/en
Priority to CN85109695A priority patent/CN1007847B/en
Priority to EP85116598A priority patent/EP0190461B1/en
Priority to DE8585116598T priority patent/DE3584243D1/en
Priority to US06/818,238 priority patent/US4837114A/en
Publication of JPS6260212A publication Critical patent/JPS6260212A/en
Priority to US07/360,101 priority patent/US5089066A/en
Priority to US07/740,442 priority patent/US5316595A/en
Publication of JPH0545045B2 publication Critical patent/JPH0545045B2/ja
Granted legal-status Critical Current

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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
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
    • 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
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0572—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes with a protective layer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/026—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets protecting methods against environmental influences, e.g. oxygen, by surface treatment

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Hard Magnetic Materials (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)

Description

【発明の詳細な説明】[Detailed description of the invention]

利用産業分野 この発明は、Fe−Ｂ−Ｒ系永久磁石材料の製
造方法に係り、Al薄膜層を被着した後、シヨツ
トピーニングを施すことにより、焼結永久磁石表
面の研削加工等に伴なう磁石特性の劣化を防止
し、さらに磁石材料の耐食性被膜の密着性を改善
した耐食性のすぐれたFe−Ｂ−Ｒ系磁石材料の
製造方法に関する。 背景技術 現在の代表的な永久磁石材料は、アルニコ、ハ
ードフエライトおよび希土類コバルト磁石であ
る。この希土類コバルト磁石は、磁気特性が格段
にすぐれているため、多種用途に利用されている
が、主成分のSm、Goは共に資源的に不足し、か
つ高価であり、今後長期間にわたつて、安定して
多量に供給されることは困難である。 そのため、磁気特性がすぐれ、かつ安価で、さ
らに資源的に豊富で今後の安定供給が可能な組成
元素からなる永久磁石材料が切望されてきた。 本出願人は先に、高価なSmやCoを含有しない
新しい高性能永久磁石としてFe−Ｂ−Ｒ系（Ｒ
はＹを含む希土類元素のうち少なくとも１種）永
久磁石を提案した（特開昭59−46008号、特開昭
59−64733号、特開昭59−89401号、特開昭59−
132104号）。 この永久磁石は、ＲとしてNdやPrを中心とす
る資源的に豊富な軽希土類を用い、Ｂ、Feを主
成分として25MGOe以上、最高では45MGOe以
上にも達する極めて高いエネルギー積を示す、す
ぐれた永久磁石である。 最近、磁気回路の高性能化、小形化に伴ない、
Fe−Ｂ−Ｒ系永久磁石材料が益々注目されてき
た。かかる用途の永久磁石材料を製造するには、
成形焼結した焼結磁石体表面の凹凸や歪みを除去
するため、あるいは表面酸化層を除去するため、
さらには磁気回路に組込むために、磁石体の全面
あるいは所要表面を切削加工あるいは研削加工す
る必要があり、加工には外周刃切断機、内周刃切
断機、表面研削機、センタレスグラインダー、ラ
ツピングマシン等が使用される。 しかしながら、Fe−Ｂ−Ｒ系永久磁石材料を
切削または研削加工すると、Fe−Ｂ−Ｒ系永久
磁石材料は、主成分として、空気中で極めて酸化
しやすく、直ちに安定な酸化物を生成する希土類
元素及び鉄を含有するため、発熱したり大気と加
工面との接触により酸化層が生成し、磁気特性の
劣化を招来する問題があつた。 また、Fe−Ｂ−Ｒ系磁気異方性焼結体からな
る永久磁石を、磁気回路に組込んだ場合に、磁石
表面に生成する酸化物により、磁気回路の出力低
下及び磁気回路間の特性のばらつきを惹起し、ま
た、表面酸化物の脱落による周辺機器への汚染の
問題があつた。 そこで、出願人は先に、上記のFe−Ｂ−Ｒ系
永久磁石の耐食性の改善のため、磁石体表面に無
電解めつき法あるいは電解めつき法により耐食性
金属めつき層を被覆した永久磁石（特願昭58−
162350号）及び磁石体表面にスプレー法あるいは
浸漬法によつて耐食性樹脂層を被覆した永久磁石
を提案（特願昭58−171907号）した。 しかし、前者のめつき法では永久磁石体が焼結
体であり有孔性のため、この孔内にめつき前処理
で酸性溶液またはアルカリ性溶液が残留し、経年
変化とともに発錆する恐れがあり、また磁石体の
耐薬品性が劣るため、めつき時に磁石表面が腐食
されて密着性・防食性が劣る問題があつた。 また後者のスプレー法による樹脂の塗装には方
向性があるため、被処理物表面全体に均一な樹脂
被膜を施すのに多大の工程、手間を要し、特に形
状が複雑な異形磁石体に均一厚みの被膜を施すこ
とは困難であり、また浸漬法では樹脂被膜厚みが
不均一になり、製品寸法精度が悪い問題があつ
た。 このため発明者らは、Fe−Ｂ−Ｒ系永久磁石
の耐食性を改善する方法として、焼結磁石体表面
に、特定粒径、硬度を有する硬質粉末よるグリツ
トブラストを施した後、薄膜形成技術にて、磁石
体表面にAl薄膜層を被着した永久磁石材料（特
願昭60−110793号）を提案した。 発明が解決しようとする課題 これにより、Fe−Ｂ−Ｒ系永久磁石は著しく
耐食性を増したが、上記Al薄膜は、蒸着法等に
おいて、蒸発したAl粒子が、磁石体表面に堆積
して形成されるため、密度不足を生じ、長期間に
わたる使用において、局部的にAl薄膜が剥離し
たり、薄膜層に亀裂を生じたり、局部的な錆発生
が懸念される問題があつた。 この発明は、希土類・ボロン・鉄を主成分とす
る新規な永久磁石材料において、焼結磁石体の切
削加工あるいは研削加工に伴なう磁気特性の劣化
を改善し、さらに、腐食性薬品等を使用あるいは
接触させることなく、密着性、防食性にすぐれた
耐食性薄膜層を被着させた永久磁石材料の製造方
法の提供を目的としている。 課題を解決するための手段 この発明は、 Ｒ（ＲはNd、Dr、Dy、Ho、Tbのうち少なくと
も１種あるいはさらに、La、Ce、Sm、Gd、Er、
Eu、Tm、Yb、Lu、Ｙのうち少なくとも１種か
らなる）10原子％〜30原子％、 B2原子％〜28原子％、 FE65原子％〜80原子％を主成分とし、主相が
正方晶相からなる焼結永久磁石体の表面に、Al
薄膜層を被着した後、シヨツトピーニングを施す
ことを特徴する永久磁石材料の製造方法である。 この発明において、焼結磁石体の表面、例えば
酸化表面相を除去した清浄表面にAl層を被着さ
せるには、真空蒸着、スパツタリング、イオンプ
レーテイング等の薄膜形成方法が適宜選定利用で
きる。また、薄膜層の厚みは、薄膜層の剥離ある
いは機械的強度の低下並びに防食性の確保等を考
慮して、30μｍ以下の厚みが好ましく、最も好ま
しくは5μｍ〜25μｍの層厚みである。 この発明において、Al薄膜層の被着前の焼結
磁石体表面に所要形状からなる硬質粉末を加圧気
体とともに噴射するグリツトブラストを行うこと
は、焼結磁石体の黒皮、酸化層や加工歪層等の表
面層を除去して、表面を清浄化させて後工程で被
着するAl薄膜層の耐食性を向上させることがで
きるため、有効な処理である。 このグリツトブラストに使用する硬質粉末とし
ては、モース硬度が５以上のAl2O3系、炭化けい
素系、ZrO2系、炭化硼素系、ガーネツト系等の
粉末があり、硬度の高いAl2O3系粉末が好まし
い。 上記の不定形硬質粉末のモース硬度が、５未満
では研削力が小さすぎて、研削処理時間に長時間
を要して好ましくない。 また、不定形硬質粉末の平均粒度を20μｍ〜
35μｍとするのは、20μｍ未満では研削力が小さ
すぎて研削に長時間を要し、また、350μｍを超
えると焼結磁石体表面の面粗度が粗くなりすぎ、
研削量が不均一となり、好ましくないためであ
る。 また、不定形硬質粉末の噴射条件として、圧力
1.0Kg／cm2未満では研削処理に長時間を要し、ま
た、圧力6.0Kg／cm2を超えると磁石体表面の研削
量が不均一となり、面粗度の劣化が懸念される。 さらに、噴射時間が0.5分間未満では研削量が
小さくかつ不均一であり、また、60分を超えると
磁石体表面の研削量が多くなり、面粗度が悪化し
て好ましくない。 また、硬質粉末の噴射用加圧流体としては、空
気あるいはAr、N2ガス等の不活性ガスが利用で
きるが、磁石体の酸化防止のためには、不活性ガ
スが好ましく、また、空気を用いる場合は、除湿
を行なつた空気が望ましい。 この発明において、シヨツトピーニング用粉末
としては、モース硬度３以上の球状硬質粉末を用
い、スチールボールやガラスビーズ等が利用で
き、被着したAl薄膜層の硬度と同等以上の硬度
であればよく、ガラスビーズが好ましい。 ピーニング用球状粉末のモース硬度が、３未満
ではAl薄膜層の硬度より小さくなり、ピーニン
グ効果が得られないため好ましくない。 また、ピーニング用球状粉末の平均粒度を30μ
ｍ〜30μｍとするのは、30μｍ未満ではAl薄膜層
に対する押圧力が小さく処理に長時間を要し、ま
た、3000μｍを超えると焼結磁石体表面の面粗度
が粗くなりすぎ、仕上面が不均一となり、好まし
くないためである。さらに好ましい平均粒度は、
40μｍから2000μｍである。 また、球状粉末の噴射条件としては、圧力1.0
Kg／cm2未満ではAl薄膜層に対する押圧力が小さ
く処理に長時間を要し、また、圧力5.0Kg／cm2を
超えるとAl薄膜層への押圧力が不均一となり、
面粗度の悪化を招来する さらに、噴射時間が１分間未満では全表面を均
一に処理できず、また、噴射時間の上限は、ピー
ニングの処理量、処理条件によつて決定される
が、60分を超えると面粗度が悪化して好ましくな
い。 永久磁石材料の成分限定理由 この発明の永久磁石材料に用いる希土類元素Ｒ
は、組成の10原子％〜30原子％を占めるが、Nd、
Pr、Dy、Ho、Tbのうち少なくとも１種、ある
いはさらに、La、Ce、Sm、Gd、Er、Eu、Tm、
Yb、Lu、Ｙのうち少なくとも１種を含むものが
好ましい。 また、通常Ｒのうち１種をもつて足りるが、実
用上は２種以上の混合物（ミツシユメタル、ジジ
ム等）を入手上の便宜等の理由により用いること
ができる。 なお、このＲは純希土類元素でなくてもよく、
工業上入手可能な範囲で製造上不避な不純物を含
有するものでも差支えない。 Ｒは、新規な上記系永久磁石材料における必須
元素であつて、10原子％未満では結晶構造がα鉄
と同一構造の立方晶組織となるため、高磁気特
性、特に高保磁力が得られず、30原子％を超える
とＲリツチな非磁性相が多くなり、残留磁束密度
（Br）が低下して、すぐれた特性の永久磁石が得
られない。よつて、Ｒは10原子％〜30原子％の範
囲とする。 Ｂは、この発明による永久磁石材料における必
須元素であつて、２原子％未満では菱面体構造が
主相となり、高い保磁力（iHc）は得られず、28
原子％を超えるとＢリツチな非磁性相が多くな
り、残留磁束密度（Br）が低下するため、すぐ
れた永久磁石が得られない。よつて、Ｂは２原子
％〜28原子％の範囲とする。 Feは、新規な上記系永久磁石における必須元
素であり、65原子％未満では残留磁束密度（Br）
が低下し、80原子％を超えると高い保磁力が得ら
れないので、Feは65原子％〜80原子％の含有と
する。 また、この発明による永久磁石材料において、
Feの一部をCoで置換することは、得られる磁石
の磁気特性を損うことなく、温度特性を改善する
ことができるが、Co置換量がFeの20％を超える
と、逆に磁気特性が劣化するため好ましくない。
Coの置換量がFeとCoの合計量で５原子％〜15原
子％の場合は（Br）は置換しない場合に比較し
て増加するため、高磁束密度を得るために好まし
い。 また、この発明による永久磁石材料は、Ｒ、
Ｂ、Feの他、工業的生産上不可避的不純物の存
在を許容できるが、Ｂの一部を4.0原子％以下の
Ｃ、3.5原子％以下のＰ、2.5原子％以下のＳ、3.5
原子％以下のCuのうち少なくとも１種、合計量
で4.0原子％以下で置換することにより、永久磁
石の製造性改善、低価格化が可能である。 また、下記添加元素のうち少なくとも１種は、
Ｒ−Ｂ−Fe系永久磁石に対してその保磁力、減
磁曲線の角型性を改善あるいは製造性の改善、低
価格化に効果があるため添加することができる。 9.5原子％以下のAl、4.5原子％以下のTi、 9.5原子％以下のＶ、8.5原子％以下のCr、 8.0原子％以下のMn、5.0原子％以下のBi、 9.5原子％以下のNb、9.5原子％以下のTa、 9.5原子％以下のMo、9.5原子％以下のＷ、 2.5原子％以下のSb、７原子％以下のGe、 3.5原子％以下のSn、5.5原子％以下のZr、 9.0原子％以下のNi、9.0原子％以下のSi、 1.1原子％以下のZn、5.5原子％以下のHf、 のうち少なくとも１種を添加含有、但し、２種以
上含有する場合は、その最大含有量は当該添加元
素のうち最大値を有するものの原子％以下の含有
させることにより、永久磁石の高保磁力化が可能
になる。 結晶相は主相が正方晶であることが、微細で均
一な合金粉末より、すぐれた磁気特性を有する焼
結永久磁石を作製するのに不可欠である。 また、この発明の永久磁石材料は平均結晶粒径
が１〜80μｍの範囲にある正方晶系の結晶構造を
有する化合物を主相とし、体積比で１％〜50％の
非磁性相（酸化物相を除く）を含むことを特徴と
する。 また、この発明の永久磁石は、磁場中プレス成
型することにより磁気的異方性磁石が得られ、ま
た、無磁界中でプレス成型することにより、磁気
的和度方性磁石を得ることができる。 作 用 この発明は、焼結磁石体表面に、Al薄膜層を
被着し、酸化や切削加工にともなう磁石特性の劣
化を改善し、さらに、所要形状からなる特定の粉
末を加圧気体とともに噴射して、該Al薄膜層の
緻密化を計り、材料と表面薄膜層との密着性を改
善し、材料の耐食性をなお一層向上させたもので
ある。 この発明による永久磁石材料は、保磁力iHc≧
1kOe、残留磁束密度Br＞4kG、を示し、最大エ
ネルギー積（BH）maxは、（BH）max≧
10MGOeを示し、最大値は25MGOe以上に達す
る。 また、この発明による永久磁石のＲの主成分
が、その50％以上をNd及びPrを主とする軽希土
類金属が占める場合で、R12原子％〜20原子％、
B4原子％〜24原子％、Fe74原子％〜80原子％を
主成分とするとき、（BH）maxが35MGOe以上
のすぐれた磁気特性を示し、特に軽希土類金属が
Ndの場合には、その最大値が45MGOe以上に達
する。 実施例 出発原料として、純度99.9％の電解鉄、フエロ
ボロン合金、純度99.7％以上のNdを使用し、こ
れらを配合後高周波溶解し、その後水冷銅鋳型に
鋳造し、16.0Nd7.0B77.0Feなる組成の鋳塊を得
た。 その後このインゴツトを、スタンプミルにより
粗粉砕し、次にボールミルにより微粉砕し、平均
粒度2.8μｍの微粉末を得た。 この微粉末を金型に挿入し、15kOeの磁界中で
配向し、磁界に垂直方向に、1.2ton／cm2の圧力で
成型した。 得られた成型体を、1100℃、１時間、Ar雰囲
気中の条件で焼結し、長さ25mm×幅40mm×厚み30
mm寸法の焼結体を得た。さらに、Ar中での800
℃、１時間と630℃、1.5時間の２段時効処理を施
した。 上記の永久磁石体を、大気中でダイヤモンド
＃200番を砥石として、回転数2400rpm、送り速
度５mm／minで、長さ５mm×幅10mm×厚み３mm寸
法に切出した。 さらに、この切出し試料に、平均粒径50μｍ、
モース硬度９の不定形Al2O3硬質粉末を用いて、
圧力2.5Kg／cm2、N2ガスの加圧気体とともに、20
分間噴射する条件のグリツトブラストを施し、上
記磁石体の表面層を除去した。 次に、真空度５×10-5Torrの真空容器内に、
上記試料を入れ、Arガスを送入し、１×
10-2TorrのArガス中、500Vの電圧で15分間の放
電を行なつた後、引続きコーテイング材料とし
て、純99.99％のAl板を用い、これを加熱して蒸
発Alをイオン化し、これらイオン化粒子が電界
に引かれて、陰極を構成する前記試験片に付着
し、Al薄膜を形成した。試験片表面に形成した
薄膜厚みは15μｍであつた。 上記イオン・プレーテイング条件は、電圧
1.5kV、10分間処理であつた。 さらに、Al薄膜層を被着した磁石体試料に、
平均粒径120μｍ、モース硬度６の球状ガラスビ
ーズ粉末を用いて、圧力1.5Kg／cm2、N2ガスの加
圧気体とともに、５分間噴射する条件のシヨツト
ピーニングを施して試験片を得た（本発明１）。 これらの試験片に耐食性試験と耐食性試験後の
薄膜の密着強度試験を行なつた。また、耐食性試
験前後の磁気特性を測定した。試験結果及び測定
結果を第１表に示す。 また、比較のため、前記の切出しままの試験片
（比較例２）及び上記試験片に、本発明と同条件
のグリツトブラストを施し、トリクレンにて３分
間溶剤脱脂し、５％NaOHにて60℃、３分間の
アルカリ脱脂した後、２％HClにて室温、10秒間
の酸洗し、ワツト浴にて電流密度4A／ｄm2、浴
温度60℃、20分間の条件にて、電気ニツケルめつ
きを行ない表面に20μｍ厚みのニツケルめつき層
を有する比較試験片（比較例３）を得た。さら
に、上記のAl薄膜層を被着させたのち、シヨツ
トピーニング処理しない比較試験片（比較例４）
を得た。 これらの比較試験片に上記の実施例１と同一の
試験及び測定を行ない、その結果を同様に第１表
に示す。 耐食性試験は、上記試験片を70℃の温度90％の
湿度の雰囲気に、500時間放置した場合の試験片
外観状況及び密着強度、耐蝕試験前後の磁気特性
でもつて評価した。また、この発明の試験片１は
上記条件で発錆するまでの時間を調べた。 また、密着強度試験は、耐蝕性試験後の本発明
１及び比較例３、４試験片を、破断して破断面を
観察することで評価した。 Field of Application This invention relates to a method for producing Fe-BR-based permanent magnet materials, in which shot peening is performed after depositing an Al thin film layer, thereby allowing grinding of the surface of a sintered permanent magnet. The present invention relates to a method for manufacturing a Fe-BR-based magnet material with excellent corrosion resistance, which prevents deterioration of magnetic properties and improves the adhesion of a corrosion-resistant coating on the magnet material. BACKGROUND ART Current representative permanent magnet materials are alnico, hard ferrite and rare earth cobalt magnets. This rare earth cobalt magnet has extremely excellent magnetic properties and is used for a variety of purposes, but the main components, Sm and Go, are both scarce and expensive, so they will not be available for a long time to come. , it is difficult to stably supply it in large quantities. Therefore, there has been a strong desire for a permanent magnet material that has excellent magnetic properties, is inexpensive, and is composed of constituent elements that are abundant in resources and can be stably supplied in the future. The applicant has previously proposed a new high-performance permanent magnet that does not contain expensive Sm or Co.
proposed a permanent magnet (at least one rare earth element containing Y) (Japanese Patent Application Laid-Open No. 59-46008,
No. 59-64733, JP-A-59-89401, JP-A-59-
No. 132104). This permanent magnet uses resource-rich light rare earths such as Nd and Pr as R, and has B and Fe as its main components, and exhibits an extremely high energy product of over 25 MGOe, reaching a maximum of over 45 MGOe. It is a permanent magnet. Recently, with the improvement in performance and miniaturization of magnetic circuits,
Fe-BR-based permanent magnet materials have been attracting more and more attention. To manufacture permanent magnet materials for such uses,
In order to remove irregularities and distortions on the surface of a sintered magnet body that has been shaped and sintered, or to remove a surface oxidation layer,
Furthermore, in order to incorporate it into a magnetic circuit, it is necessary to cut or grind the entire surface or the required surface of the magnet body, and the processing requires an external blade cutting machine, an internal blade cutting machine, a surface grinding machine, a centerless grinder, a wrapping machine, etc. machines etc. are used. However, when Fe-BR-based permanent magnet material is cut or ground, the main component of Fe-BR-based permanent magnet material is rare earth, which is extremely easily oxidized in the air and immediately forms stable oxides. Since it contains elements and iron, it generates heat and an oxidized layer is formed due to contact with the atmosphere and the processed surface, resulting in a problem of deterioration of magnetic properties. In addition, when a permanent magnet made of an Fe-BR-based magnetically anisotropic sintered body is incorporated into a magnetic circuit, oxides generated on the surface of the magnet may cause a decrease in the output of the magnetic circuit and characteristics between the magnetic circuits. In addition, there was a problem of contamination of peripheral equipment due to shedding of surface oxides. Therefore, in order to improve the corrosion resistance of the above-mentioned Fe-BR-based permanent magnet, the applicant first developed a permanent magnet whose surface was coated with a corrosion-resistant metal plating layer by electroless plating or electrolytic plating. (Special application 1982-
162350) and a permanent magnet whose surface was coated with a corrosion-resistant resin layer by spraying or dipping (Japanese Patent Application No. 171907/1982). However, in the former plating method, since the permanent magnet body is a sintered body and is porous, acidic or alkaline solutions may remain in the holes during the plating pretreatment, which may cause rust over time. Also, since the chemical resistance of the magnet body is poor, the magnet surface is corroded during plating, resulting in poor adhesion and corrosion resistance. Furthermore, since resin coating using the latter spray method is directional, it takes a lot of steps and effort to apply a uniform resin coating to the entire surface of the object to be treated, especially on irregularly shaped magnets with complex shapes. It is difficult to apply a thick coating, and the dipping method results in uneven resin coating thickness, resulting in poor product dimensional accuracy. Therefore, as a method for improving the corrosion resistance of Fe-BR permanent magnets, the inventors conducted grit blasting with hard powder having a specific particle size and hardness on the surface of the sintered magnet, and then formed a thin film. We proposed a permanent magnet material (Japanese Patent Application No. 110793/1983) in which a thin Al film layer is coated on the surface of the magnet body. Problems to be Solved by the Invention As a result, Fe-B-R permanent magnets have significantly improved corrosion resistance, but the Al thin film is formed by evaporated Al particles deposited on the magnet surface during vapor deposition, etc. As a result, there was a problem that the aluminum thin film may peel off locally, cracks may occur in the thin film layer, and local rust may occur during long-term use. This invention improves the deterioration of magnetic properties caused by cutting or grinding of sintered magnet bodies in a new permanent magnet material whose main components are rare earth elements, boron, and iron. The object of the present invention is to provide a method for producing a permanent magnet material on which a corrosion-resistant thin film layer with excellent adhesion and anti-corrosion properties is deposited without using or contacting the material. Means for Solving the Problems This invention provides R (R is at least one of Nd, Dr, Dy, Ho, Tb, or furthermore, La, Ce, Sm, Gd, Er,
Contains at least one of Eu, Tm, Yb, Lu, and Y) 10 to 30 at%, B2 to 28 at%, FE65 to 80 at%, and the main phase is tetragonal. On the surface of the sintered permanent magnet body consisting of
This method of producing a permanent magnet material is characterized in that shot peening is performed after depositing a thin film layer. In the present invention, in order to deposit an Al layer on the surface of the sintered magnet, for example, a clean surface from which an oxidized surface phase has been removed, thin film forming methods such as vacuum evaporation, sputtering, and ion plating can be appropriately selected and utilized. Further, the thickness of the thin film layer is preferably 30 μm or less, most preferably 5 μm to 25 μm, in consideration of peeling of the thin film layer, reduction in mechanical strength, and ensuring corrosion resistance. In this invention, performing grit blasting, in which hard powder having a desired shape is injected together with pressurized gas, onto the surface of the sintered magnet before the Al thin film layer is deposited on the surface of the sintered magnet can eliminate black spots, oxidized layers, etc. on the sintered magnet. This is an effective treatment because it removes surface layers such as process-strained layers, cleans the surface, and improves the corrosion resistance of the Al thin film layer that will be deposited in a subsequent process. The hard powders used for grit blasting include Al 2 O 3 based powders, silicon carbide based powders, ZrO 2 based powders, boron carbide based powders, garnet based powders, etc., which have a Mohs hardness of 5 or more . O 3 based powder is preferred. If the Mohs hardness of the above-mentioned amorphous hard powder is less than 5, the grinding force will be too small and the grinding process will take a long time, which is not preferable. In addition, the average particle size of the amorphous hard powder is 20 μm ~
The reason why the diameter is 35 μm is that if it is less than 20 μm, the grinding force will be too small and it will take a long time to grind, and if it exceeds 350 μm, the surface roughness of the sintered magnet will become too rough.
This is because the amount of grinding becomes uneven, which is not desirable. In addition, pressure is required as an injection condition for amorphous hard powder.
If the pressure is less than 1.0 Kg/cm 2 , the grinding process will take a long time, and if the pressure exceeds 6.0 Kg/cm 2 , the amount of grinding on the surface of the magnet will become uneven, leading to concerns about deterioration of the surface roughness. Further, if the spraying time is less than 0.5 minutes, the amount of grinding will be small and non-uniform, and if the spraying time exceeds 60 minutes, the amount of grinding on the surface of the magnet will increase, which is undesirable as the surface roughness will deteriorate. In addition, air or an inert gas such as Ar or N2 gas can be used as the pressurized fluid for injecting the hard powder, but in order to prevent oxidation of the magnet body, an inert gas is preferable. If used, it is desirable to use dehumidified air. In this invention, as the powder for shot peening, a spherical hard powder with a Mohs hardness of 3 or more is used, and steel balls, glass beads, etc. can be used, as long as they have a hardness equal to or higher than the hardness of the deposited Al thin film layer. , glass beads are preferred. If the Mohs hardness of the spherical powder for peening is less than 3, the hardness will be lower than that of the Al thin film layer, and the peening effect will not be obtained, which is not preferable. In addition, the average particle size of spherical powder for peening is 30μ
m~30μm is because if it is less than 30μm, the pressing force against the Al thin film layer will be small and it will take a long time to process, and if it exceeds 3000μm, the surface roughness of the sintered magnet will become too rough and the finished surface will be poor. This is because it becomes non-uniform, which is not desirable. A more preferable average particle size is
It is 40μm to 2000μm. In addition, the injection conditions for spherical powder are as follows: pressure 1.0
If the pressure is less than 5.0 Kg/cm 2 , the pressing force on the Al thin film layer will be small and the process will take a long time, and if the pressure exceeds 5.0 Kg/cm 2 , the pressing force on the Al thin film layer will be uneven.
In addition, if the spraying time is less than 1 minute, the entire surface cannot be treated uniformly, and the upper limit of the spraying time is determined by the amount of peening to be processed and the processing conditions. If it exceeds 10 minutes, the surface roughness deteriorates, which is not preferable. Reason for limiting the components of the permanent magnet material Rare earth element R used in the permanent magnet material of this invention
accounts for 10 to 30 atom% of the composition, but Nd,
At least one of Pr, Dy, Ho, Tb, or in addition, La, Ce, Sm, Gd, Er, Eu, Tm,
Those containing at least one of Yb, Lu, and Y are preferred. Furthermore, although it is usually sufficient to use one type of R, in practice, a mixture of two or more types (Mitsushimetal, dididim, etc.) can be used for reasons such as convenience of availability. Note that this R may not be a pure rare earth element,
It may contain impurities that are unavoidable during production within an industrially available range. R is an essential element in the new above-mentioned permanent magnet material, and if it is less than 10 atomic %, the crystal structure becomes cubic, which is the same structure as α iron, so high magnetic properties, especially high coercive force, cannot be obtained. If it exceeds 30 atomic %, the R-rich nonmagnetic phase increases, the residual magnetic flux density (Br) decreases, and a permanent magnet with excellent characteristics cannot be obtained. Therefore, R should be in the range of 10 atomic % to 30 atomic %. B is an essential element in the permanent magnet material according to the present invention, and if it is less than 2 atomic %, the rhombohedral structure becomes the main phase, and a high coercive force (iHc) cannot be obtained.
If it exceeds atomic %, the B-rich nonmagnetic phase increases and the residual magnetic flux density (Br) decreases, making it impossible to obtain an excellent permanent magnet. Therefore, B should be in the range of 2 atomic % to 28 atomic %. Fe is an essential element in the new above-mentioned permanent magnet, and if it is less than 65 at%, the residual magnetic flux density (Br)
Fe content decreases and high coercive force cannot be obtained if it exceeds 80 atom %, so Fe is contained in an amount of 65 atom % to 80 atom %. Further, in the permanent magnet material according to the present invention,
Replacing a portion of Fe with Co can improve the temperature characteristics of the obtained magnet without impairing its magnetic properties, but if the Co substitution amount exceeds 20% of Fe, the magnetic properties is undesirable because it causes deterioration.
When the amount of Co substitution is 5 at % to 15 at % based on the total amount of Fe and Co, (Br) increases compared to the case where no substitution is made, which is preferable for obtaining a high magnetic flux density. Further, the permanent magnet material according to the present invention has R,
In addition to B and Fe, the presence of unavoidable impurities in industrial production can be tolerated, but a part of B can be replaced by 4.0 atom% or less of C, 3.5 atom% or less of P, 2.5 atom% or less of S, 3.5
By substituting at least one type of Cu in a total amount of 4.0 atomic % or less, it is possible to improve the manufacturability and lower the price of permanent magnets. In addition, at least one of the following additional elements is
It can be added to R-B-Fe permanent magnets because it is effective in improving the coercive force and squareness of the demagnetization curve, improving manufacturability, and reducing costs. 9.5 at% or less Al, 4.5 at% or less Ti, 9.5 at% or less V, 8.5 at% or less Cr, 8.0 at% or less Mn, 5.0 at% or less Bi, 9.5 at% or less Nb, 9.5 Ta less than 9.5 atom%, Mo less than 9.5 atom%, W less than 9.5 atom%, Sb less than 2.5 atom%, Ge less than 7 atom%, Sn less than 3.5 atom%, Zr less than 5.5 atom%, 9.0 atom % or less Ni, 9.0 atomic % or less Si, 1.1 atomic % or less Zn, 5.5 atomic % or less Hf.However, if two or more types are contained, the maximum content is By including the additive element having the maximum value at atomic % or less, it is possible to increase the coercive force of the permanent magnet. It is essential that the main crystalline phase be tetragonal in order to produce a sintered permanent magnet with superior magnetic properties than a fine and uniform alloy powder. In addition, the permanent magnet material of the present invention has a compound having a tetragonal crystal structure with an average crystal grain size in the range of 1 to 80 μm as the main phase, and a nonmagnetic phase (oxide (excluding phases). Further, the permanent magnet of the present invention can be press-molded in a magnetic field to obtain a magnetically anisotropic magnet, and by press-molded in a non-magnetic field to obtain a magnetically unidirectional magnet. . Function This invention improves the deterioration of magnetic properties caused by oxidation and cutting by depositing an Al thin film layer on the surface of a sintered magnet, and furthermore, injects a specific powder having a desired shape together with pressurized gas. In this way, the Al thin film layer is densified, the adhesion between the material and the surface thin film layer is improved, and the corrosion resistance of the material is further improved. The permanent magnet material according to this invention has a coercive force iHc≧
1kOe, residual magnetic flux density Br＞4kG, maximum energy product (BH)max is (BH)max≧
It shows 10MGOe, and the maximum value reaches more than 25MGOe. Further, in the case where the main component of R in the permanent magnet according to the present invention is light rare earth metals mainly consisting of Nd and Pr, R12 atomic % to 20 atomic %,
When the main components are B4 atomic% to 24 atomic% and Fe74 atomic% to 80 atomic%, it shows excellent magnetic properties with (BH)max of 35 MGOe or more, especially light rare earth metals.
In the case of Nd, the maximum value reaches 45MGOe or more. Example As starting materials, electrolytic iron with a purity of 99.9%, ferroboron alloy, and Nd with a purity of 99.7% or more are used. After mixing these, they are high-frequency melted, and then cast in a water-cooled copper mold to obtain a composition of 16.0Nd7.0B77.0Fe. An ingot was obtained. Thereafter, this ingot was coarsely ground using a stamp mill, and then finely ground using a ball mill to obtain a fine powder with an average particle size of 2.8 μm. This fine powder was inserted into a mold, oriented in a magnetic field of 15 kOe, and molded at a pressure of 1.2 ton/cm 2 in a direction perpendicular to the magnetic field. The obtained molded body was sintered at 1100°C for 1 hour in an Ar atmosphere to obtain a size of 25 mm long x 40 mm wide x 30 mm thick.
A sintered body with dimensions of mm was obtained. Furthermore, 800 in Ar
A two-stage aging treatment was performed at 630°C for 1 hour and at 630°C for 1.5 hours. The above permanent magnet body was cut into a size of 5 mm in length, 10 mm in width, and 3 mm in thickness using a #200 diamond as a grindstone in the atmosphere at a rotation speed of 2400 rpm and a feed rate of 5 mm/min. Furthermore, this cut sample had an average particle size of 50 μm,
Using amorphous Al 2 O 3 hard powder with a Mohs hardness of 9,
Pressure 2.5Kg/cm 2 , with pressurized N 2 gas, 20
Grit blasting was performed under conditions of spraying for a minute to remove the surface layer of the magnet. Next, in a vacuum container with a vacuum degree of 5 × 10 -5 Torr,
Put the above sample in, send Ar gas, and
After discharging for 15 minutes at a voltage of 500 V in Ar gas at 10 -2 Torr, a 99.99% pure Al plate was used as the coating material, and this was heated to ionize the evaporated Al. The particles were attracted by the electric field and adhered to the test piece constituting the cathode, forming an Al thin film. The thickness of the thin film formed on the surface of the test piece was 15 μm. The above ion plating conditions are
The treatment was at 1.5 kV for 10 minutes. Furthermore, on a magnet sample coated with an Al thin film layer,
Using spherical glass bead powder with an average particle diameter of 120 μm and a Mohs hardness of 6, a test piece was obtained by shot peening at a pressure of 1.5 Kg/cm 2 and spraying with pressurized N 2 gas for 5 minutes. (Invention 1). These test pieces were subjected to a corrosion resistance test and a thin film adhesion strength test after the corrosion resistance test. In addition, the magnetic properties before and after the corrosion resistance test were measured. The test results and measurement results are shown in Table 1. For comparison, the as-cut test piece (Comparative Example 2) and the above test piece were subjected to grit blasting under the same conditions as the present invention, solvent degreased for 3 minutes with trichlene, and 5% NaOH. After alkaline degreasing at 60°C for 3 minutes, pickling with 2% HCl at room temperature for 10 seconds, electric nickel was washed in a Watts bath at a current density of 4A/dm 2 and a bath temperature of 60°C for 20 minutes. A comparative test piece (Comparative Example 3) having a 20 μm thick nickel plating layer on the surface was obtained by plating. Furthermore, a comparative test piece (Comparative Example 4) was coated with the above Al thin film layer and was not subjected to shot peening treatment.
I got it. These comparative test pieces were subjected to the same tests and measurements as in Example 1 above, and the results are also shown in Table 1. In the corrosion resistance test, the test piece was left in an atmosphere of 70° C., 90% humidity, and 500 hours, and the appearance, adhesion strength, and magnetic properties before and after the corrosion test were evaluated. Further, the time taken for the test piece 1 of the present invention to rust under the above conditions was investigated. Further, the adhesion strength test was evaluated by breaking the test pieces of Invention 1 and Comparative Examples 3 and 4 after the corrosion resistance test and observing the broken surfaces.

【表】 発明の効果 実施例の第１表より明らかなように、焼結永久
磁石体の表面にAl薄膜層を被着した後、シヨツ
トピーニングを施すこの発明方法により、切削加
工あるいは研削加工による磁気特性の劣化が改善
され、さらに、耐食性にすぐれた永久磁石が得ら
れ、その効果が著しいことが分る。 この発明の製造方法は、ＲとしてNdやPrを中
心とする資源的に豊富な軽希土類を用い、Ｂ、
Feを主成分として25MGOe以上、最高では
45MGOe以上にも達する極めて高いエネルギー
積並びに、高残留磁束密度、高保磁力を示す、す
ぐれた永久磁石であり、かつ研削加工及び酸化層
による磁気特性の劣化を防止し、かつ防蝕性にす
ぐれたAl薄膜を表面に安定被着したFe−Ｂ−Ｒ
系永久磁石材料を安価に得ることができる。[Table] Effects of the Invention As is clear from Table 1 of Examples, cutting or grinding is possible by applying shot peening to the surface of a sintered permanent magnet body after depositing an Al thin film layer on the surface of the sintered permanent magnet. It can be seen that the deterioration of magnetic properties caused by this process is improved, and a permanent magnet with excellent corrosion resistance is obtained, and the effect is remarkable. The manufacturing method of this invention uses resource-rich light rare earths such as Nd and Pr as R, and B,
25MGOe or more with Fe as the main component, at the highest
It is an excellent permanent magnet that exhibits an extremely high energy product reaching more than 45 MGOe, high residual magnetic flux density, and high coercive force.Al Fe-BR with a thin film stably adhered to the surface
permanent magnet material can be obtained at low cost.

Claims (1)

【特許請求の範囲】 １ Ｒ（ＲはNd、Pr、Dy、Ho、Tbのうち少な
くとも１種あるいはさらに、La、Ce、Sm、Gd、
Er、Eu、Tm、Yb、Lu、Ｙのうち少なくとも１
種からなる）10原子％〜30原子％、B2原子％〜
28原子％、 Fe65原子％〜80原子％を主成分とし、主相が
正方晶相からなる焼結永久磁石体の表面に、Al
薄膜層を被着した後、シヨツトピーニングを施す
ことを特徴とする永久磁石材料の製造方法。[Claims] 1 R (R is at least one of Nd, Pr, Dy, Ho, Tb, or furthermore, La, Ce, Sm, Gd,
At least one of Er, Eu, Tm, Yb, Lu, Y
(consisting of seeds) 10 atomic% ~ 30 atomic%, B2 atomic% ~
The main components are 28 at% Fe, 65 at% to 80 at% Fe, and the main phase is a tetragonal phase.
A method for producing a permanent magnet material, which comprises applying shot peening after depositing a thin film layer.
JP60200890A 1984-12-24 1985-09-10 Manufacture of permanent magnet material Granted JPS6260212A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
JP60200890A JPS6260212A (en) 1985-09-10 1985-09-10 Manufacture of permanent magnet material
CN85109695A CN1007847B (en) 1984-12-24 1985-12-24 Process for producing magnets having improved corrosion resistance
EP85116598A EP0190461B1 (en) 1984-12-24 1985-12-27 Process for producing permanent magnets and permanent magnet
DE8585116598T DE3584243D1 (en) 1984-12-24 1985-12-27 METHOD FOR PRODUCING PERMANENT MAGNETS AND PERMANENT MAGNET.
US06/818,238 US4837114A (en) 1984-12-24 1986-01-13 Process for producing magnets having improved corrosion resistance
US07/360,101 US5089066A (en) 1984-12-24 1989-06-01 Magnets having improved corrosion resistance
US07/740,442 US5316595A (en) 1984-12-24 1991-08-05 Process for producing magnets having improved corrosion resistance

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP60200890A JPS6260212A (en) 1985-09-10 1985-09-10 Manufacture of permanent magnet material

Publications (2)

Publication Number Publication Date
JPS6260212A JPS6260212A (en) 1987-03-16
JPH0545045B2 true JPH0545045B2 (en) 1993-07-08

Family

ID=16431950

Family Applications (1)

Application Number Title Priority Date Filing Date
JP60200890A Granted JPS6260212A (en) 1984-12-24 1985-09-10 Manufacture of permanent magnet material

Country Status (1)

Country Link
JP (1) JPS6260212A (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0758673B1 (en) * 1995-07-21 1999-10-06 Rohm And Haas Company Method for improving drying speed in printing process and fast dry printing ink used therein
EP1136587B1 (en) * 2000-03-23 2013-05-15 Hitachi Metals, Ltd. Deposited-film forming apparatus
MY128597A (en) 2000-07-10 2007-02-28 Neomax Co Ltd Method of inhibiting production of projections in metal deposited-film

Also Published As

Publication number Publication date
JPS6260212A (en) 1987-03-16

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