JP2791659B2 - Manufacturing method of corrosion resistant permanent magnet - Google Patents

Manufacturing method of corrosion resistant permanent magnet

Info

Publication number
JP2791659B2
JP2791659B2 JP62052283A JP5228387A JP2791659B2 JP 2791659 B2 JP2791659 B2 JP 2791659B2 JP 62052283 A JP62052283 A JP 62052283A JP 5228387 A JP5228387 A JP 5228387A JP 2791659 B2 JP2791659 B2 JP 2791659B2
Authority
JP
Japan
Prior art keywords
permanent magnet
atomic
oxide film
resin layer
less
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
JP62052283A
Other languages
Japanese (ja)
Other versions
JPS63217601A (en
Inventor
浩子 中村
宏樹 徳原
幸光 宮尾
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.)
Hitachi Metals 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 JP62052283A priority Critical patent/JP2791659B2/en
Publication of JPS63217601A publication Critical patent/JPS63217601A/en
Application granted granted Critical
Publication of JP2791659B2 publication Critical patent/JP2791659B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

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

Landscapes

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

Description

【発明の詳細な説明】 利用産業分野 この発明は、高磁気特性を有しかつ耐食性にすぐれた
Fe−Ｂ−Ｒ系永久磁石に係り、焼結永久磁石体の被研削
加工表面に特定雰囲気で厚み１〜５μｍの高温酸化被膜
層を形成し、この高温酸化被膜層上に、不揮発残部が特
定濃度の樹脂溶液にて、浸透、密着性よく樹脂層を設
け、耐食性、特に、60℃、相対湿度90％の雰囲気におけ
る耐食性を貯しく向上させたFe−Ｂ−Ｒ系永久磁石の製
造方法に関する。 背景技術 出願人は先に、NdやPrを中心とする資源的に豊富な軽
希土類を用いてB,Feを主成分とし、高価なSmやCoを含有
せず、従来の希土類コバルト磁石の最高特性を大幅に越
える新しい高性能永久磁石として、Fe−Ｂ−Ｒ系永久磁
石を提案した（特開昭59−46008号公報、特開昭59−894
01号公報）。 前記磁石合金のキュリー点、一般に、300℃〜370℃で
あるが、Feの一部をCoにて置換することにより、より高
いキュリー点を有するFe−Ｂ−Ｒ系永久磁石を得（特開
昭59−64733号、特開昭59−132104号）、さらに、前記C
o含有のFe−Ｂ−Ｒ系希土類永久磁石と同等以上のキュ
リー点並びにより高い（BH）maxを有し、その温度特
性、特に、iHcを向上させるため、希土類元素（Ｒ）と
してNdやPr等の軽希土類を中心としたCo含有のFe−Ｂ−
Ｒ系希土類永久磁石のＲの一部にDy、Tb等の重希土類の
うち少なくとも１種を含有することにより、25MGOe以上
の極めて高い（BH）maxを保有したままで、iHcをさらに
向上させたCo含有のFe−Ｂ−Ｒ系希土類永久磁石を提案
（特開昭60−34005号）した。 しかしながら、上記のすぐれた磁気特性を有するFe−
Ｂ−Ｒ系磁気異方性焼結体からなる永久磁石は主成分と
して、空気中で酸化あるいは水酸化し次第に酸化物ある
いは水酸化物を生成し易い希土類元素及び鉄を含有する
ため、磁気回路に組込んだ場合に、磁石表面に生成する
酸化物あるいは水酸化物により、磁気回路の出力低下及
び磁気回路間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った。 そこで、出願人は、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っき法あるい
は電解めっき法により耐食性金属めっき層を被覆した永
久磁石（特願昭58−162350号）を提案したが、本めっき
法では永久磁石体が焼結体で有孔性のため、この孔内に
めっき前処理での酸性溶液またはアルカリ溶液が残留
し、経年変化とともに腐食する恐れがあり、また磁石体
の耐薬品性が劣るため、めっき時に磁石表面が腐食され
て密着性・防蝕性が劣る問題があった。そのため磁石体
表面にスプレー法あるいは浸漬法によって、厚膜の耐食
性樹脂層を被覆した永久磁石を提案（特願昭58−171907
号）した。 従来技術の問題点 従来、前記Fe−Ｂ−Ｒ系永久磁石表面に耐食性樹脂層
を設けるには、不揮発残部の多い樹脂溶液を使用するた
め、前記樹脂溶液の粘性が大きく、焼結磁石製造工程の
中で、焼結、時効処理、研削加工後の乾燥のための熱処
理の各工程で磁石表面に生成した高温酸化被膜上に、充
分な密着性を持たせ、かつ簡単に被着させることが困難
であった。そのため、永久磁石体表面の高温酸化被膜を
研削加工等で除去した後、耐食性樹脂層を設ける必要が
あり、製造工程が煩雑となる問題があった。また、前記
高温酸化被膜を除去した後、耐食性樹脂層を設けた場
合、60℃、相対湿度90％の雰囲気における耐食性は十分
でない問題があった。 発明の目的 この発明は、Fe−Ｂ−Ｒ系永久磁石体の耐食性、特
に、60℃、相対湿度90％の雰囲気における耐食性を貯し
く向上させることを目的とし、また、耐食性を向上させ
るための前記永久磁石体の製造工程において、磁石体表
面の高温酸化被膜を除去することなく、簡単な処理にて
前記耐食性を付与できる製造方法を目的としている。 発明の構成 この発明は、60℃、相対湿度90％の雰囲気におけるFe
−Ｂ−Ｒ系永久磁石体の耐食性を向上させ得る簡単な工
程の表面処理を目的に、表面に酸化被膜を生成した永久
磁石体の表面処理について種々検討した結果、焼結永久
磁石体の製造工程における焼結後または焼結時効処理後
に希削加工を施し、被研削加工表面に、真空中、不活性
ガス、還元性ガスのいずれかの雰囲気中で熱処理を行う
ことにより生成した数μｍ厚みの高温酸化被膜の表面粗
度が粗いことを知見し、これを除去することなく、所要
濃度に不揮発残部を低経した樹脂溶液に浸漬あるいは該
溶液を塗布することにより、表面粗度の粗い酸化被膜へ
の浸透性及び密着性にすぐれた耐酸化性樹脂層を付与で
きることを知見し、この発明を完成したものである。 すなわち、この発明は、 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％〜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に研削加工を施し、真空中、不活
性ガス、還元性ガスのいずれかの雰囲気中で熱処理を行
い、厚み１〜５μｍの高温酸化被膜層を形成させた後、 前記永久磁石体を不揮発残部5wt％〜20wt％含有の樹脂
溶液中に浸漬するか、あるいは永久磁石体に前記樹脂溶
液を塗布後焼付けし、 前記永久磁石体の高温酸化被膜層上に耐酸化性樹脂層を
設けたことを特徴とする耐食性永久磁石の製造方法であ
る。 発明の好ましい実施態様 発明者らは、Fe−Ｂ−Ｒ系焼結永久磁石体表面に高温
酸化被膜を生成させ、表面に高温酸化被膜を有する永久
磁石体表面に耐酸化性樹脂層を被着させる製造方法とし
て下記のの３方法を知見し、また、製品の寸法精
度や形状性を向上させるには研削加工工程が必要になる
ため、の２方法を提案する。 すなわち、成型体を焼結し、時効処理した後耐酸化性
樹脂を被着させる、あるいは成型体を焼結し寸法精度出
しのための研削加工し、時効処理した後に耐酸化性樹脂
を被着させる、あるいは成形体を焼結し、時効処理した
後、寸法精度出しのための研削加工し、その後研削液除
去および乾燥のための熱処理をした後に耐酸化性樹脂を
被着させる方法である。要するに、 焼結→時効処理→耐酸化性樹脂層を被着 焼結→研削加工→時効処理→耐酸化性樹脂層を被着 焼結→時効処理→研削加工→熱処理→耐酸化性樹脂層
を被着の方法である。 この発明において、焼結は、還元性または非酸化性雰
囲気中にて900℃〜1200℃の温度にて行うことが好まし
い。 また、この発明において、高温酸化被膜を生成させる
ための時効処理は、一段時効処理あるいは多段時効処理
のいずれでもよく、一段時効処理の場合、真空中、不活
性ガス、還元性ガス中で、350℃〜焼結温度以下、好ま
しくは450℃〜800℃の温度にて、0.5時間〜８時間の処
理が好ましく、また、二段以上の多段時効処理の場合
は、真空中、不活性ガス、還元性ガス中で、800℃〜900
℃で0.5時間〜６時間の初段時効後、二段目以降は400℃
〜750℃で２時間〜30時間の条件が好ましい。 さらに、研削加工後に研削液除去および乾燥のために
行う熱処理は、上記時効処理と同様の真空中、不活性ガ
ス、還元性ガス中で100℃〜600℃で行うことが好まし
い。 また、この発明において、Fe−Ｂ−Ｒ系永久磁石体表
面に生成させる高温酸化被膜の厚みは、１μｍ〜５μｍ
が好ましい。１μｍ未満では耐食性改善効果が少なく、
また５μｍ以上では磁石特性が低下するとともに耐酸化
性樹脂層の密着性を低下し、耐食性も低下するため好ま
しくなく、さらに好ましくは１μｍ〜２μｍである。 この発明において、酸化被膜上に被着する耐酸化性樹
脂としては、エポキシ樹脂、熱硬化型アクリル樹脂、フ
エノール樹脂、ウレタン樹脂、メラミン樹脂、ビニル樹
脂、シリコン樹脂、等の塗料用樹脂を用い、溶液中の不
揮発残部を5wt％〜20wt％に希釈することにより、酸化
被膜への浸透性を高め、密着度を向上させる。 溶液中の不揮発残部が5wt％未満では、焼結永久磁石
体の酸化被膜面上に形成される樹脂層が薄く耐食性の改
善硬化が少なく、また、20wt％を越えると、溶液粘度が
高くなり、酸化被膜への浸透性が悪く密着性が低下し、
耐食性が劣化するため好ましくない。 前記樹脂溶液は、真空含浸法、浸漬法、スプレー法、
ハケ塗り法、等により、永久磁石体の酸化被膜上に被着
し、その後焼付けるが、得られた樹脂層の厚みは、５μ
ｍ以上であれば永久磁石体の耐食性が向上するが、25μ
ｍを越えると、すぐれた寸法精度が得難くなるため、５
μｍ〜25μｍ厚みが好ましい。 さらに上記の樹脂中に酸化亜鉛、クロム酸亜鉛、鉛等
の防錆用顔料を含有してもよく、あるいはベンゾトリア
ゾールを含有するものでもよい。 永久磁石の成分限定理由 この発明の永久磁石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、G
d、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種をもって足りるが、実用上は
２種以上の混合物（ミッシュメタル，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可避な不純物を含有するもの
でも差支えない。 Ｒは、上記系永久磁石における、必須元素であって、
10原子％未満では、結晶構造がα−鉄と同一構造の立方
晶組織が析出するため、高磁気特性、特に高保磁力が得
られず、30原子％を越えると、Ｒリッチな非磁性相が多
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。よって、希土類元素は、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における、必須元素で
あって、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％を越えると、
Ｂリッ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。よっ
て、Ｂは、２原子％〜28原子％の範囲とする。 Feは、上記系永久磁石において、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％
を越えると、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、この発明の永久磁石において、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％を越えると、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、この発明の永久磁石は、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S
n、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は平均結晶粒径が１〜80μ
ｍ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％の比磁性相（酸化物相を除
く）を含むことを特徴とする。 この発明による永久磁石は、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％、Fe7
4原子％〜80原子％、を主成分とするとき、（BH）max35
MGOe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。 また、この発明において、60℃、相対湿度90％の環境
に長時間放置する耐食試験で、極めて高い耐食性を示す
永久磁石として、Nb11at％〜15at％、Dy0.2at％〜3.0at
％、かつNdとDyの総量が12at％〜17at％であり、B5at％
〜8at％、Co0.5at％〜13at％、Al0.5at％〜4at％、C100
0ppm以下を含有し、残部Fe及び不可避的不純物からなる
場合が好ましい。 実 施 例 実施例１ 出発原料として、純度99.9％の電解鉄、フェロボロン
合金、純度99.7％以上のNd、Dy、Co、Al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、
14Nd−0.5Dy−7B−6Co−2Al−残Fe（at％）なる組成の
鋳塊を得た。その後インゴットを粗粉砕、次に微粉砕
し、平均粒度３μｍの微粉末を得た。 この微粉末を金型に挿入し、12kOeの磁石中で配向
し、磁界と直角方向に、1.5t/cm2の圧力で長さ20mm×幅
10mm×厚み8mm寸法に成形した。 得られた成形体を1100℃、１時間、Ar中の条件で焼結
した。得られた焼結体を全面研削加工し、表面の高温酸
化被膜を除去した後、Ar中で580℃、２時間の時効処理
を施して、永久磁石を作製した。なお、得られた永久磁
石体表面の高温酸化被膜厚みは１〜２μｍであった。 次に、前記永久磁石体試験片を、溶剤にて洗浄し乾燥
させた後、不揮発残部10wt％のシリコン樹脂溶液中に浸
漬し、酸化被膜面に被着させ、常温にて３時間乾燥させ
たのち、150℃で１時間焼付けを施し、高温酸化被膜上
に５μｍ〜10μｍの耐酸化性樹脂層を設けた。 60℃、相対湿度90％の雰囲気中に500時間放置したの
ち、磁石特性、発錆状況及び樹脂層密着性（碁盤目試
験：樹脂層面に碁盤目状に切れ目を入れて粘着テープで
樹脂層の剥がれを観察する）を調べた結果を表１に示
す。 実施例２ 実施例１と同一組成、同一条件にて作製した成形体を
1100℃１時間Ar中で焼結して焼結体を得た。得られた焼
結体をAr中で580℃２時間の時効処理をした後、焼結体
を全面研削加工して表面の高温酸化被膜を除去した後、
真空中で400℃２時間の熱処理を施し、永久磁石を作製
した。得られた永久磁石体表面の高温酸化被膜の厚みは
１〜２μｍであった。 次に、前記永久磁石体試験片を実施例１と同一の条件
で、高温酸化被膜上に５μｍ〜10μｍの耐酸化性樹脂層
を設けた。 60℃、相対湿度90％の雰囲気中に500時間放置したの
ち、磁石特性、発錆状況及び樹脂層密着性を調べた結果
を表１に示す。 比較例１ 実施例１で作製した焼結永久磁石体を全面研削加工し
て表面の高温酸化被膜を除去した後、実施例１と同一の
被着条件にて、永久磁石体表面にシリコン樹脂層を設け
た。 60℃、相対湿度90％の雰囲気中に500時間放置したの
ち、磁石特性、発錆状況及び樹脂層密着性を調べた結果
を表１に示す。 比較例２ 実施例１で作製した焼結永久磁石体表面の高温酸化被
膜を除去することなく、該永久磁石体を不揮発残部30at
％のシリコン樹脂溶液中に浸漬した後、実施例１と同一
条件にて乾燥、焼付けして樹脂層を設けた。 60℃、相対湿度90％の雰囲気中に500時間放置したの
ち、磁石特性、発錆状況及び樹脂層密着性を調べた結果
を表１に示す。発明の効果 この発明は、Fe−Ｂ−Ｒ系永久磁石体表面に、特定雰
囲気で厚み１〜５μｍの高温酸化被膜層を形成し、この
高温酸化被膜層上に、不揮発残部が特定濃度の樹脂溶液
にて、浸透、密着性よく樹脂層を設けることにより、実
施例に明らかな如く、耐食性、特に、60℃、相対湿度90
％の雰囲気における耐食性を著しく向上させたFe−Ｂ−
Ｒ系永久磁石が得られる。Description: FIELD OF THE INVENTION This invention has high magnetic properties and excellent corrosion resistance.
According to the Fe-BR-based permanent magnet, a high-temperature oxide film layer having a thickness of 1 to 5 μm is formed in a specific atmosphere on a surface to be processed of a sintered permanent magnet body, and a non-volatile residue is specified on the high-temperature oxide film layer. The present invention relates to a method for producing a Fe-BR-based permanent magnet in which a resin layer is provided with good penetration and adhesion with a resin solution having a high concentration, and corrosion resistance, particularly in an atmosphere at 60 ° C. and a relative humidity of 90%, is stored and improved. . Background Art The applicant has previously used B and Fe as main components using resource-rich light rare earths such as Nd and Pr, does not contain expensive Sm and Co, and is the best of conventional rare earth cobalt magnets. As a new high-performance permanent magnet which greatly exceeds the characteristics, an Fe-BR-based permanent magnet has been proposed (Japanese Patent Application Laid-Open Nos. 59-46008 and 59-894).
No. 01). Although the Curie point of the magnetic alloy is generally 300 ° C. to 370 ° C., a part of Fe is replaced with Co to obtain a Fe—BR—based permanent magnet having a higher Curie point (Japanese Unexamined Patent Publication (Kokai) No. 2002-157572). (JP-A-59-64733, JP-A-59-132104) and the above-mentioned C
It has a Curie point equal to or higher than that of o-containing Fe-BR based rare earth permanent magnets and a higher (BH) max, and in order to improve its temperature characteristics, particularly iHc, Nd or Pr as a rare earth element (R) Co-containing Fe-B- centered on light rare earths such as
By including at least one of heavy rare earths such as Dy and Tb in a part of R of the R-based rare earth permanent magnet, iHc is further improved while maintaining a very high (BH) max of 25MGOe or more. A Co-containing Fe-BR based rare earth permanent magnet was proposed (JP-A-60-34005). However, Fe-
A permanent magnet made of a BR-based magnetic anisotropic sintered body contains, as a main component, a rare earth element and iron that easily generate an oxide or a hydroxide when oxidized or hydroxylated in the air, and thus a magnetic circuit. When incorporated in a magnet, the oxides or hydroxides generated on the magnet surface cause a reduction in the output of the magnetic circuit and variations between the magnetic circuits, and the problem of contamination of peripheral devices due to the loss of the surface oxide. was there. In order to improve the corrosion resistance of the above-described Fe-BR permanent magnet, the applicant has proposed a permanent magnet having a magnet body surface coated with a corrosion-resistant metal plating layer by an electroless plating method or an electrolytic plating method (Japanese Patent Application No. -162350), but in this plating method, since the permanent magnet body is a sintered body and porous, an acidic solution or an alkaline solution during plating pretreatment remains in these holes and corrodes with aging. There is a problem that the magnet surface may be corroded at the time of plating, and the adhesion and corrosion resistance may be deteriorated due to the possibility of fear and the poor chemical resistance of the magnet body. Therefore, a permanent magnet in which a thick corrosion-resistant resin layer is coated on the magnet body surface by spraying or dipping is proposed (Japanese Patent Application No. 58-171907).
No.) Problems of conventional technology Conventionally, in order to provide a corrosion-resistant resin layer on the surface of the Fe-BR-based permanent magnet, a resin solution having a large amount of non-volatile residue is used. In the process, sintering, aging treatment, and heat treatment for drying after grinding are performed. It was difficult. Therefore, after removing the high-temperature oxide film on the surface of the permanent magnet body by grinding or the like, it is necessary to provide a corrosion-resistant resin layer, and there has been a problem that the manufacturing process becomes complicated. Further, when the corrosion-resistant resin layer is provided after removing the high-temperature oxide film, there is a problem that the corrosion resistance in an atmosphere at 60 ° C. and a relative humidity of 90% is not sufficient. SUMMARY OF THE INVENTION The present invention aims at accumulating and improving the corrosion resistance of Fe-BR based permanent magnet bodies, particularly in an atmosphere of 60 ° C. and 90% relative humidity, and for improving the corrosion resistance. It is an object of the present invention to provide a manufacturing method capable of imparting the corrosion resistance by a simple treatment without removing a high-temperature oxide film on the surface of the magnet body in a manufacturing process of the permanent magnet body. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing Fe
As a result of various studies on the surface treatment of a permanent magnet body having an oxide film formed on its surface for the purpose of surface treatment in a simple process capable of improving the corrosion resistance of a BR permanent magnet body, production of a sintered permanent magnet body After the sintering or aging treatment in the process, the surface is subjected to rare cutting, and the surface to be ground is subjected to a heat treatment in a vacuum, an inert gas, or a reducing gas atmosphere, and has a thickness of several μm. It was found that the surface roughness of the high-temperature oxide film was rough, and without removing it, it was immersed in a resin solution with a low concentration of non-volatile residue at the required concentration or was coated with the solution to obtain a rough surface. The inventors have found that an oxidation-resistant resin layer having excellent permeability and adhesion to a coating film can be provided, and have completed the present invention. That is, the present invention relates to a method for producing a compound according to the present invention, wherein R (R is at least one of Nd, Pr, Dy, Ho, Tb or La, Ce, Sm, Gd, Er, Eu, Tm, Yb, Lu, Y
Of at least one of the following): 10% to 30% by atom, B2% to 28% by atom, Fe65% to 80% by atom as the main component, and grinding into a sintered permanent magnet body whose main phase is a tetragonal phase After performing processing, and performing heat treatment in an atmosphere of any of an inert gas and a reducing gas in a vacuum to form a high-temperature oxide film layer having a thickness of 1 to 5 μm, the permanent magnet body has a nonvolatile residue of 5 wt% or less. It is characterized in that an oxidation-resistant resin layer is provided on the high-temperature oxide film layer of the permanent magnet body by dipping in a resin solution containing 20 wt% or applying the resin solution to a permanent magnet body and baking. This is a method for producing a corrosion-resistant permanent magnet. Preferred Embodiments of the Invention The inventors produce a high-temperature oxide film on the surface of an Fe-BR-based sintered permanent magnet body, and apply an oxidation-resistant resin layer to the surface of the permanent magnet body having a high-temperature oxide film on the surface. The following three methods are found as manufacturing methods to be performed, and the following two methods are proposed because a grinding process is required to improve dimensional accuracy and shape of a product. In other words, after sintering the molded body and aging, apply the oxidation-resistant resin, or sinter the molded body, grind it to obtain dimensional accuracy, and apply the oxidation-resistant resin after aging. Alternatively, after sintering and aging a molded body, grinding is performed to obtain dimensional accuracy, and then heat treatment is performed for removing a grinding fluid and drying, and then an oxidation-resistant resin is applied. In short, sintering → aging treatment → sintering of oxidation resistant resin layer → grinding → aging treatment → sintering of oxidation resistant resin layer → aging treatment → grinding → heat treatment → oxidation resistant resin layer The method of deposition. In the present invention, sintering is preferably performed at a temperature of 900 ° C to 1200 ° C in a reducing or non-oxidizing atmosphere. Further, in the present invention, the aging treatment for forming the high-temperature oxide film may be either a single-stage aging treatment or a multi-stage aging treatment.In the case of the single-stage aging treatment, a vacuum treatment is performed in an inert gas or a reducing gas. C. to a sintering temperature or lower, preferably at a temperature of 450 to 800.degree. C., for 0.5 to 8 hours is preferable. In the case of two or more stages of aging treatment, an inert gas, 800 ° C ~ 900 in neutral gas
After the first stage aging for 0.5 to 6 hours at ℃, 400 ℃ after the second stage
Preferred is a condition of 750750 ° C. for 2 hours to 30 hours. Further, the heat treatment for removing the grinding fluid and drying after the grinding is preferably performed at 100 ° C. to 600 ° C. in an inert gas or a reducing gas in the same vacuum as the aging treatment. In the present invention, the thickness of the high-temperature oxide film formed on the surface of the Fe-BR-based permanent magnet is 1 μm to 5 μm.
Is preferred. If it is less than 1 μm, the effect of improving corrosion resistance is small,
On the other hand, when the thickness is 5 μm or more, the magnet properties are reduced, the adhesion of the oxidation-resistant resin layer is reduced, and the corrosion resistance is also reduced. In the present invention, as the oxidation-resistant resin to be adhered on the oxide film, epoxy resin, thermosetting acrylic resin, phenol resin, urethane resin, melamine resin, vinyl resin, silicone resin, using a paint resin, By diluting the non-volatile residue in the solution to 5 wt% to 20 wt%, the permeability to the oxide film is increased, and the adhesion is improved. If the non-volatile residue in the solution is less than 5% by weight, the resin layer formed on the oxide film surface of the sintered permanent magnet body is thin, and the improvement in corrosion resistance hardens, and if it exceeds 20% by weight, the solution viscosity increases, Poor permeability to oxide film and poor adhesion,
It is not preferable because the corrosion resistance is deteriorated. The resin solution is a vacuum impregnation method, an immersion method, a spray method,
The brush is applied on the oxide film of the permanent magnet body by a brush coating method or the like, and then baked. The thickness of the obtained resin layer is 5 μm.
m or more, the corrosion resistance of the permanent magnet is improved.
m, it is difficult to obtain excellent dimensional accuracy.
A thickness between 25 μm and 25 μm is preferred. Further, the above resin may contain a rust preventive pigment such as zinc oxide, zinc chromate, lead or the like, or may contain benzotriazole. Reasons for Limiting Components of Permanent Magnet The rare earth element R used in the permanent magnet of the present invention has a composition
Occupies at least 10 at% to 30 at%, but at least one of Nd, Pr, Dy, Ho, and Tb, or further, La, Ce, Sm, G
Those containing at least one of d, Er, Eu, Tm, Yb, Lu, and Y are preferable. Usually, one kind of R is sufficient, but in practice, a mixture of two or more kinds (mish metal, dymium, etc.) can be used for reasons such as convenience in obtaining. Note that R may not be a pure rare earth element, and may contain impurities which are unavoidable in production within the industrially available range. R is an essential element in the above permanent magnet,
If it is less than 10 atomic%, a cubic structure having the same crystal structure as that of α-iron precipitates, so that high magnetic properties, especially high coercive force cannot be obtained. If it exceeds 30 atomic%, an R-rich nonmagnetic phase is formed. As a result, the residual magnetic flux density (Br) decreases, and a permanent magnet having excellent characteristics cannot be obtained. Therefore, the rare earth element is set in the range of 10 to 30 atomic%. B is an essential element in the permanent magnet according to the present invention, and if less than 2 atomic%, the rhombohedral structure becomes the main phase,
High coercive force (iHc) cannot be obtained.
Since a B-rich nonmagnetic phase increases and the residual magnetic flux density (Br) decreases, an excellent permanent magnet cannot be obtained. Therefore, B is in the range of 2 to 28 atomic%. Fe is an essential element in the above permanent magnets, and 65
If it is less than 80 atomic%, the residual magnetic flux density (Br) decreases,
If Fe exceeds 3, a high coercive force cannot be obtained, so Fe is contained in an amount of 65 to 80 atomic%. Further, in the permanent magnet of the present invention, substituting part of Fe with Co can improve the temperature characteristics without impairing the magnetic characteristics of the obtained magnet, but the amount of Co substitution is reduced by Fe.
If it exceeds 20%, the magnetic characteristics deteriorate, which is not preferable. The substitution amount of Co is 5 atomic% to 15 in the total amount of Fe and Co.
In the case of atomic%, since (Br) increases as compared with the case without substitution, it is preferable to obtain a high magnetic flux density. In addition, the permanent magnet of the present invention can tolerate the presence of impurities unavoidable in industrial production, in addition to R, B, and Fe.
Manufacture of permanent magnets by substituting at least one of 4.0 atomic% or less of C, 3.5 atomic% or less of P, 2.5 atomic% or less of S, and 3.5 atomic% or less of Cu with a total amount of 4.0 atomic% or less. It is possible to improve the performance and reduce the price. Further, at least one of the following additional elements is RB
-It can be added to the Fe-based permanent magnet because it is effective for improving the coercive force and the squareness of the demagnetization curve or improving the productivity and reducing the price. 9.5 atomic% or less Al, 4.5 atomic% or less Ti, 9.5 atomic%
V below, Cr not more than 8.5 atomic%, Mn not more than 8.0 atomic%, 5.
0 at% or less Bi, 9.5 at% or less Nb, 9.5 at% or less Ta, 9.5 at% or less Mo, 9.5 at% or less W, 2.5 at% or less Sb, 7 at% or less Ge, 3.5 Atomic% or less S
n, 5.5 atomic% or less of Zr, 9.0 atomic% or less of Ni, 9.0 atomic%
At least one of the following Si, Zn of 1.1 at% or less, and Hf of 5.5 at% or less is added and contained. However, when two or more are contained, the maximum content is the maximum value of the added elements. By containing at most atomic% of those having, it becomes possible to increase the coercive force of the permanent magnet. It is indispensable that the main phase of the crystal phase be tetragonal in order to produce a sintered permanent magnet having better magnetic properties than a fine and uniform alloy powder. The permanent magnet of the present invention has an average crystal grain size of 1 to 80 μm.
A compound having a tetragonal crystal structure in the range of m as a main phase and containing a specific magnetic phase (excluding an oxide phase) of 1% to 50% by volume. The permanent magnet according to the present invention exhibits a coercive force iHc ≧ 1 kOe, a residual magnetic flux density Br> 4 kG, and a maximum energy product (BH) max
Indicates (BH) max ≧ 10MGOe, and the maximum value reaches 25MGOe or more. The main component of R of the permanent magnet according to the present invention is
In the case where 50% or more is occupied by light rare earth metals mainly composed of Nd and Pr, R12 atomic% to 20 atomic%, B4 atomic% to 24 atomic%, Fe7
When 4 atomic% to 80 atomic% is the main component, (BH) max35
It shows excellent magnetic properties higher than MGOe, especially when the light rare earth metal is Nd, its maximum value reaches 45MGOe or more. Further, in the present invention, Nb 11 at% to 15 at%, Dy 0.2 at% to 3.0 at, as permanent magnets exhibiting extremely high corrosion resistance in a corrosion resistance test left for a long time in an environment of 60 ° C. and 90% relative humidity.
%, And the total amount of Nd and Dy is 12at% to 17at%, and B5at%
~ 8at%, Co0.5at% ~ 13at%, Al0.5at% ~ 4at%, C100
It is preferable that it contains 0 ppm or less and the balance consists of Fe and unavoidable impurities. EXAMPLES Example 1 As starting materials, electrolytic iron of 99.9% purity, ferroboron alloy, Nd, Dy, Co, and Al of 99.7% or more in purity were used, and after mixing, high frequency melting was performed and then cast into a water-cooled copper mold. And
An ingot having a composition of 14Nd-0.5Dy-7B-6Co-2Al-remaining Fe (at%) was obtained. Thereafter, the ingot was coarsely ground and then finely ground to obtain a fine powder having an average particle size of 3 μm. The fine powder was inserted into a mold, oriented in a magnet 12 kOe, the magnetic field and perpendicular, length 20 mm × width at a pressure of 1.5 t / cm 2
It was molded to a size of 10 mm x thickness of 8 mm. The obtained molded body was sintered at 1100 ° C. for 1 hour under conditions in Ar. The whole surface of the obtained sintered body was ground to remove a high-temperature oxide film, and then subjected to aging treatment at 580 ° C. for 2 hours in Ar to produce a permanent magnet. The thickness of the high-temperature oxide film on the surface of the obtained permanent magnet body was 1 to 2 μm. Next, the permanent magnet test piece was washed with a solvent and dried, and then immersed in a silicon resin solution having a nonvolatile residue of 10% by weight, applied to the oxide film surface, and dried at room temperature for 3 hours. Thereafter, baking was performed at 150 ° C. for 1 hour, and an oxidation resistant resin layer of 5 μm to 10 μm was provided on the high-temperature oxide film. After leaving for 500 hours in an atmosphere of 60 ° C. and 90% relative humidity, the magnet properties, rusting state and adhesion of the resin layer (cross-cut test: cut the resin layer surface in a grid pattern and apply adhesive tape to the resin layer) Table 1 shows the results obtained by examining peeling. Example 2 A molded body produced under the same composition and under the same conditions as in Example 1 was prepared.
The sintered body was obtained by sintering in Ar at 1100 ° C. for 1 hour. After aging treatment of the obtained sintered body in Ar at 580 ° C for 2 hours, the sintered body is entirely ground to remove a high-temperature oxide film on the surface,
Heat treatment was performed at 400 ° C. for 2 hours in a vacuum to produce a permanent magnet. The thickness of the high-temperature oxide film on the surface of the obtained permanent magnet was 1-2 μm. Next, the permanent magnet test piece was provided with an oxidation-resistant resin layer of 5 μm to 10 μm on the high-temperature oxide film under the same conditions as in Example 1. Table 1 shows the results of examining the magnet properties, the rusting state, and the adhesion of the resin layer after leaving for 500 hours in an atmosphere at 60 ° C. and a relative humidity of 90%. Comparative Example 1 After the sintered permanent magnet body produced in Example 1 was entirely ground to remove a high-temperature oxide film on the surface, a silicon resin layer was formed on the surface of the permanent magnet body under the same deposition conditions as in Example 1. Was provided. Table 1 shows the results of examining the magnet properties, the rusting state, and the adhesion of the resin layer after leaving for 500 hours in an atmosphere at 60 ° C. and a relative humidity of 90%. Comparative Example 2 Without removing the high-temperature oxide film on the surface of the sintered permanent magnet body produced in Example 1, the permanent magnet body was replaced with a non-volatile residue of 30 at.
%, And then dried and baked under the same conditions as in Example 1 to form a resin layer. Table 1 shows the results of examining the magnet properties, the rusting state, and the adhesion of the resin layer after leaving for 500 hours in an atmosphere at 60 ° C. and a relative humidity of 90%. Effect of the Invention The present invention forms a high-temperature oxide film layer having a thickness of 1 to 5 μm in a specific atmosphere on the surface of a Fe—BR-based permanent magnet body, By providing a resin layer with good permeation and adhesion in a solution, as is clear from the examples, corrosion resistance, in particular, at 60 ° C. and a relative humidity of 90
% Fe-B- with significantly improved corrosion resistance in an atmosphere of
An R-based permanent magnet is obtained.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 宮尾 幸光 大阪府三島郡島本町江川２丁目15−17 住友特殊金属株式会社山崎製作所内 (56)参考文献 特開 昭60−63901（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) H01F 1/00 - 1/04 H01F 41/00 - 41/02 C22C 33/00 - 33/02────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukimitsu Miyao 2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Sumitomo Special Metals Co., Ltd. Yamazaki Works (56) References JP-A-60-63901 (JP, A) (58) Field surveyed (Int.Cl. 6 , DB name) H01F 1/00-1/04 H01F 41/00-41/02 C22C 33/00-33/02

Claims (1)

(57)【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、L
u、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に研
削加工を施し、真空中、不活性ガス、還元性ガスのいず
れかの雰囲気中で熱処理を行い、厚み１〜５μｍの高温
酸化被膜層を形成させた後、前記永久磁石体を不揮発残
部5wt％〜20wt％含有の樹脂溶液中に浸漬するか、ある
いは永久磁石体に前記樹脂溶液を塗布後焼付けし、前記
永久磁石体の高温酸化被膜層上に耐酸化性樹脂層を設け
たことを特徴とする耐食性永久磁石の製造方法。(57) [Claims] R (R is at least one of Nd, Pr, Dy, Ho, and Tb, or La, Ce, Sm, Gd, Er, Eu, Tm, Yb, L
u, Y) At least 30 atomic%, 2 atomic% to 28 atomic% of B, 65 atomic% to 80 atomic% of Fe, and a sintered phase in which the main phase is a tetragonal phase After grinding the magnet body, performing heat treatment in an atmosphere of any of an inert gas and a reducing gas in a vacuum to form a high-temperature oxide film layer having a thickness of 1 to 5 μm, An oxidation-resistant resin layer is provided on the high-temperature oxide film layer of the permanent magnet body by dipping in a resin solution containing the remaining 5 wt% to 20 wt% or by baking after applying the resin solution to the permanent magnet body. A method for producing a corrosion-resistant permanent magnet, comprising:
JP62052283A 1987-03-06 1987-03-06 Manufacturing method of corrosion resistant permanent magnet Expired - Lifetime JP2791659B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62052283A JP2791659B2 (en) 1987-03-06 1987-03-06 Manufacturing method of corrosion resistant permanent magnet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62052283A JP2791659B2 (en) 1987-03-06 1987-03-06 Manufacturing method of corrosion resistant permanent magnet

Related Child Applications (1)

Application Number Title Priority Date Filing Date
JP05421196A Division JP3208057B2 (en) 1996-02-16 1996-02-16 Corrosion resistant permanent magnet

Publications (2)

Publication Number Publication Date
JPS63217601A JPS63217601A (en) 1988-09-09
JP2791659B2 true JP2791659B2 (en) 1998-08-27

Family

ID=12910468

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62052283A Expired - Lifetime JP2791659B2 (en) 1987-03-06 1987-03-06 Manufacturing method of corrosion resistant permanent magnet

Country Status (1)

Country Link
JP (1) JP2791659B2 (en)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63230852A (en) * 1987-03-18 1988-09-27 Honda Motor Co Ltd Nd-fe-b permanent magnetic material
JP2001160508A (en) * 1999-09-24 2001-06-12 Sumitomo Special Metals Co Ltd R-Fe-B PERMANENT MAGNET AND ITS MANUFACTURING METHOD
KR100877875B1 (en) * 2001-06-14 2009-01-13 신에쓰 가가꾸 고교 가부시끼가이샤 Corrosion Resistant Rare Earth Magnet and Its Preparation
CN1938795B (en) 2004-03-31 2012-05-02 Tdk株式会社 Rare-earth magnet and its manufacturing method
JP2006156853A (en) * 2004-11-30 2006-06-15 Tdk Corp Rare earth magnet
JP4811143B2 (en) * 2006-06-08 2011-11-09 日立金属株式会社 R-Fe-B rare earth sintered magnet and method for producing the same
JP3129837U (en) * 2006-12-13 2007-03-08 技研プロセス有限会社 Reusable aluminum foil baking container
JP6003085B2 (en) 2012-02-27 2016-10-05 株式会社ジェイテクト Magnet manufacturing method
JP2014007278A (en) 2012-06-25 2014-01-16 Jtekt Corp Method for producing magnet, and magnet
CN104599829A (en) * 2015-01-05 2015-05-06 宁波韵升股份有限公司 Method for improving magnetic property of sintered NdFeB magnet

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6063901A (en) * 1983-09-17 1985-04-12 Sumitomo Special Metals Co Ltd Permanent magnet superior in resistance to oxidation
JPS6114502U (en) * 1984-06-26 1986-01-28 三菱電機株式会社 Transmission power amplifier with polarization demultiplexing function

Also Published As

Publication number Publication date
JPS63217601A (en) 1988-09-09

Similar Documents

Publication Publication Date Title
JPH0374012B2 (en)
JP2844269B2 (en) Corrosion resistant permanent magnet and method for producing the same
JP2791659B2 (en) Manufacturing method of corrosion resistant permanent magnet
JPH056322B2 (en)
JP2003257721A (en) Sintered rare-earth magnet
JPH0422007B2 (en)
JPS6217149A (en) Manufacture of sintered permanent magnet material
JP2003257768A (en) Manufacturing method for rare earth sintered magnet
JP3208057B2 (en) Corrosion resistant permanent magnet
JPH0569282B2 (en)
JPH0422008B2 (en)
JP2553843B2 (en) Method of manufacturing permanent magnet with excellent corrosion resistance
JP2631493B2 (en) Manufacturing method of corrosion resistant permanent magnet
JP2631492B2 (en) Manufacturing method of corrosion resistant permanent magnet
JPH0445573B2 (en)
JPS6377103A (en) Rare-earth magnet excellent in corrosion resistance and manufacture thereof
JP3108400B2 (en) Permanent magnet with excellent corrosion resistance
JP2720038B2 (en) Manufacturing method of permanent magnet
JPH0752685B2 (en) Corrosion resistant permanent magnet
JP3234306B2 (en) Corrosion resistant permanent magnet
JP4600627B2 (en) Rare earth permanent magnet manufacturing method
JPH0831363B2 (en) Method for manufacturing corrosion-resistant permanent magnet
JP2551797B2 (en) Method of manufacturing permanent magnet material
JPS6338555A (en) Magnet material containing rare earth element and having superior corrosion resistance
JP3411605B2 (en) Corrosion resistant permanent magnet

Legal Events

Date Code Title Description
S533 Written request for registration of change of name

Free format text: JAPANESE INTERMEDIATE CODE: R313533

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

EXPY Cancellation because of completion of term