JPH01261806A - Rare earth magnet and its manufacture - Google Patents
Rare earth magnet and its manufactureInfo
- Publication number
- JPH01261806A JPH01261806A JP9054888A JP9054888A JPH01261806A JP H01261806 A JPH01261806 A JP H01261806A JP 9054888 A JP9054888 A JP 9054888A JP 9054888 A JP9054888 A JP 9054888A JP H01261806 A JPH01261806 A JP H01261806A
- Authority
- JP
- Japan
- Prior art keywords
- rare earth
- hot
- magnet
- resistant metal
- rust
- 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.)
- Pending
Links
- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 22
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 17
- 238000004519 manufacturing process Methods 0.000 title claims description 13
- 229910052751 metal Inorganic materials 0.000 claims abstract description 23
- 239000002184 metal Substances 0.000 claims abstract description 23
- 239000000843 powder Substances 0.000 claims abstract description 18
- 238000000034 method Methods 0.000 claims abstract description 17
- 238000001192 hot extrusion Methods 0.000 claims abstract description 15
- 239000000463 material Substances 0.000 claims description 25
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 23
- 239000000956 alloy Substances 0.000 claims description 18
- 229910045601 alloy Inorganic materials 0.000 claims description 17
- 239000011248 coating agent Substances 0.000 claims description 9
- 238000000576 coating method Methods 0.000 claims description 9
- 238000001125 extrusion Methods 0.000 claims description 7
- 238000003825 pressing Methods 0.000 claims description 6
- 230000005540 biological transmission Effects 0.000 claims description 4
- 238000001513 hot isostatic pressing Methods 0.000 claims description 4
- 238000005520 cutting process Methods 0.000 claims description 3
- 238000005260 corrosion Methods 0.000 abstract description 8
- 229910001004 magnetic alloy Inorganic materials 0.000 abstract description 8
- 230000007797 corrosion Effects 0.000 abstract description 7
- 239000010935 stainless steel Substances 0.000 abstract description 6
- 229910001220 stainless steel Inorganic materials 0.000 abstract description 6
- 230000002706 hydrostatic effect Effects 0.000 abstract description 5
- 239000000696 magnetic material Substances 0.000 abstract description 4
- 229910052747 lanthanoid Inorganic materials 0.000 abstract 2
- 150000002602 lanthanoids Chemical class 0.000 abstract 2
- 238000011049 filling Methods 0.000 description 8
- 238000007789 sealing Methods 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- 238000005336 cracking Methods 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000001816 cooling Methods 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 238000012856 packing Methods 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 229910000976 Electrical steel Inorganic materials 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010894 electron beam technology Methods 0.000 description 2
- 230000005415 magnetization Effects 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 239000004575 stone Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229910020598 Co Fe Inorganic materials 0.000 description 1
- 229910002519 Co-Fe Inorganic materials 0.000 description 1
- 229910001374 Invar Inorganic materials 0.000 description 1
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 229910003271 Ni-Fe Inorganic materials 0.000 description 1
- 229910018106 Ni—C Inorganic materials 0.000 description 1
- 229910001069 Ti alloy Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000009694 cold isostatic pressing Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910000833 kovar Inorganic materials 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 229910001172 neodymium magnet Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 238000009931 pascalization Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Landscapes
- Manufacturing Cores, Coils, And Magnets (AREA)
Abstract
Description
本発明は、Ｒ−Ｆｅ−Ｂ系の永久磁石とその製造方法に
関する。
［従来の技術ｌ
Ｎｄ −Ｆｅ −Ｂ系に代表されるＲ−Ｆｅ −Ｂ系〔
Ｒはｌａ系希土類元素〕永久磁石は、すぐれた磁気特性
を買われて、広い分野で採用が試みられている。
この磁石の一般的な製法は、溶製した合金を鋳造したイ
ンゴットを粉砕し、磁場中で配向しつつ成形して焼結し
、必要な熱処理を施してから磁化する工程からなる。
とくに高い磁気特性は、Ｒ−Ｆｅ −Ｂ系磁石合金の溶
湯を超急冷装置により急冷薄帯にし、それを粉砕した材
料を使用することによって得られる。
磁石合金粉末を不活性雰囲気中、温度的７００℃でホッ
トプレスにより成形し、磁化させると等方性磁石となる
。 ホットプレス俊、ざらに不活性雰囲気中、やはり約
７００℃で圧下率５０％以上の塑性変形を行なうと、磁
化容易軸（Ｃ軸）が変形時の流れ方向と直交する加工集
合組織が得られ、これを磁化すれば、最大エネルギー積
（Ｂ Ｈ） ｍａｘが極めて大きな異方性磁石が得られ
る。
ところが、いずれの製法によるにしても、この磁石は錆
びやすく、これが最大の問題である。
そのほか、インゴットの粉末を用いる方法では、焼結時
に変形が起りやすいことと、十分な異方性がなく、とく
にラジアル方向の磁気特性を高くすることができないと
いう制約がある。 急冷薄帯の粉末を用いれば高い磁気
異方性が得られるが、保磁力ｉＨｏを高くできないとい
う難点がある。
この磁石においては、結晶粒が大きいとｉＨｏが低くな
るところ、２回の加熱工程中に結晶粒が成長することが
避は難いからである。
いまひとつの大きな問題は、この材料が室温ではきわめ
て硬く脆いため、加工は５００〜８００℃の狭い温度範
囲内で熱間で行なうしかなく、それでも加工ワレが発生
しやすいということである。
［発明が解決しようとする課題］
本発明の目的は、Ｒ−Ｆｅ −Ｂ系磁石の最大の問題で
ある錆の防止に関し、従来の塗装やメツキに代え、また
はそれと併用することのできる対策を提供することにあ
る。
［課題を解決するための手段］
本発明の希土類磁石は、Ｒ−Ｆｅ−Ｂ系永久磁石合金の
粉末の熱間静水圧プレス体または熱間押出しプレス体か
ら切り出した磁石材料を磁化してなり、表面が上記加工
の際の容器として用いた錆びにくい金属で被覆されてい
ることを特徴とする。
上記の系において、ＲはＮｄで代表されるｌａ系希土類
元素でおる。 この磁石は、少量のＧｏ。
ＤＶ２０３などの１１石性能を向上させるための物質や
、Ｇａ、Ｎｉ 、Ｚｎ、Ｐｂ、Ａ、Ｉ！などの耐食性、
耐熱性、加工性を改善するための物質を含んでいてもよ
い。
「錆びにくい金属」とは、Ｒ−Ｆｅ −Ｂ系永久磁石合
金との対比において錆びにくいものという意味であって
、ステンレス鋼はその代表であるが、軟鋼やケイ素鋼、
Ｆｅ−Ｎｉ系合金（３６％Ｎｉ−Ｆｅ、４２％Ｎｉ −
Ｆｅ ） 、Ｆｅ −Ｎｉ −Ｃ。
合金（２９％Ｎｉ −１７％Ｃｏ −Ｆｅ ＞、Ｆｅ
−Ａｉ系合金（Ｆｅ−１３％ＡＭ）、銅、銅基合金、ア
ルミニウム、アルミ基合金、Ｔｉ合金等も包含される。
本発明の希土類磁石の代表的な例は、第１図および第２
図に示すような、リング状の希土類磁石である。 これ
は円筒形の熱間押出しプレス体から切り出したものであ
って、ラジアル方向に磁気異方性を有し、磁石（１）の
内側および外側が、たとえば５ＵＳ３０４ステンレス鋼
のような錆びにくい金属（２Ａ、２Ｂ）で被覆されてい
る。
本発明の希土類磁石の製造方法は、Ｒ−Ｆｅ−Ｂ系永久
磁石合金の粉末を錆びにくい金属の缶内に充填して真空
吸引下に密封し、５００℃以上の温度で熱間静水圧プレ
スまたは熱間押出しプレスして高密度の焼結体とし、所
定の寸法に切断して表面に錆びにくい金属の被覆を有す
る磁石材料を得、これを磁化することからなる。
粉末の充填は、俊の焼結工程において熱間静水圧プレス
を行なう場合は、カサ密度にして真密度の３０％以上あ
れば９５％以上の密度の製品が得られるが、熱間押出し
の場合は５０％以上の充填密度が必要である。 いずれ
にしても、できるだけ高密度の充填をすることが望まし
い。 それには、つぎのような手法がある。
最も簡単なものは振動充填法であって、缶に撮動を加え
つつ粉末を装入することにより、理論密度比にして約５
５％の充填ができる。
いまひとつは、缶に装入した粉末を冷間プレスすること
であって、３〜７トン／ｄの圧力をかけることにより、
理論密度比的８０％の充填が行なえる。 また、冷間静
水圧プレスを行なえば、８５％の充填が可能である。
最高の充填密度を得るには、磁石合金の粉末を缶に入れ
、１０’Ｔｏｒｒより低圧の真空下または不活性ガス雰
囲気下に５００〜８００℃に加熱して、ホットプレスす
るとよい。 これにより、理論密度比的９５％に到達す
る。 ホットプレスに先立って、磁石合金の粉末を冷間
で圧粉成形しておくのもよい。
上記いずれかの手段で磁石合金粉末を充填した缶は、蓋
をして、溶接などの方法でとりつける。
振動充填の場合は、蓋をつけておいてから充填すること
も可能である。
このようにして用意した充填体を、続いて真空槽内に置
いて脱気したのち、開口部を電子ビーム溶接などで溶接
密封して缶封体とする。 このときの真空度は、１０’
Ｔｏｒｒまたはそれより強い減圧とすることが望ましい
。
缶封体は、続いて熱間静水圧プレスにかけるか、または
熱間押出しプレスする。 後者の場合には、まず加熱し
て加工温度まで昇温させる。 これは、もちろん大気中
で行なってよい。 温度は、変形能からみて５００℃以
上とする必要があり、それより低いと加工ワレを生じや
すく、磁気的異方性が得られない。 また、８００℃を
超える温度は、結晶粒の成長が著しくなって磁気特性を
そこなう。
これらを総合すると、７００〜７５０℃の範囲が最適で
ある。 加熱時間は、結晶粒の成長を避けるよう、なる
べく短くしたい。 従って、加熱手段は高周波誘導や通
電のように、速やかに昇温できるものが好ましい。
ラジアル異方性の高いリング状の磁石を得るには、円筒
形の内部をもつ缶を用いて、熱間で前方または漬方の押
出しプレスを行なう。 この熱間押出しプレスは、静水
圧の加わる条件下に実施することが好ましい。 第３図
は、上記のようにして得た中空の缶封体に対して、それ
を行なっているところを示す。 加熱した缶封体３をコ
ンテナー５内に収容し、ステム６で（図では上方から矢
印方向に）押すことによって、ダイ８Ａとマンドレル８
Ｂの間でこれが成形され、パイプ９となって（図では下
方に）押し出される。
コンテナー５内には、加工温度で粘性をもち非圧縮性の
媒体７、たとえば耐熱グリースを封入して型の合わせ目
をシールしておけば、ステム６の移動によりコンテナー
内部の空間容積が縮小して、媒体内に高い静水圧が発生
する。 この静水圧は、缶封体３の全表面に対して圧縮
応力として作用し、その変形に伴うワレを防ぐことがで
きる。 この場合の静水圧の高さは３，０００〜１０，
０００に’ｊ／ａｉが適当で、これより低圧ではワレの
発生を防ぐ効果が乏しく、これより高圧では型の強度が
耐えないであろう。
リング状の磁石は、たとえばモータのロータにする場合
はシャフトをとりつけるなど、動力伝達材をそれに装着
したり、あるいは磁気回路形成材を装着したりして使用
することが多い。 このような部品は、熱間静水圧プレ
スに際してリングにする缶封体の内部に挿入しておいた
り、熱間押出しプレスに際して押出しプレス体内部に挿
入するなどの手法によっても装着することができる。The present invention relates to an R-Fe-B permanent magnet and a method for manufacturing the same. [Conventional technology R-Fe-B system represented by Nd-Fe-B system]
[R is a rare earth element of the La series] Permanent magnets are being used in a wide range of fields due to their excellent magnetic properties. The general manufacturing method for this magnet consists of the steps of pulverizing an ingot made by casting a melted alloy, shaping and sintering it while orienting it in a magnetic field, and magnetizing it after performing the necessary heat treatment. Particularly high magnetic properties can be obtained by using a material obtained by quenching a molten R-Fe-B magnet alloy into a thin ribbon using an ultra-quench cooling device and pulverizing the molten metal. When the magnet alloy powder is hot-pressed in an inert atmosphere at a temperature of 700° C. and magnetized, it becomes an isotropic magnet. When plastic deformation is performed at a rolling reduction rate of 50% or more in an inert atmosphere at about 700°C, a deformed texture is obtained in which the axis of easy magnetization (C-axis) is perpendicular to the flow direction during deformation. , if this is magnetized, an anisotropic magnet with an extremely large maximum energy product (B H) max can be obtained. However, no matter which manufacturing method is used, these magnets are susceptible to rust, which is the biggest problem. In addition, the method using ingot powder has limitations in that it is easily deformed during sintering and lacks sufficient anisotropy, making it impossible to improve magnetic properties, especially in the radial direction. Although high magnetic anisotropy can be obtained by using quenched ribbon powder, there is a drawback that the coercive force iHo cannot be increased. In this magnet, if the crystal grains are large, the iHo will be low, but this is because it is inevitable that the crystal grains will grow during the two heating steps. Another major problem is that this material is extremely hard and brittle at room temperature, so processing must be done hot within a narrow temperature range of 500 to 800°C, and even then processing cracks are likely to occur. [Problems to be Solved by the Invention] The purpose of the present invention is to provide a countermeasure that can be used in place of or in combination with conventional painting and plating to prevent rust, which is the biggest problem with R-Fe-B magnets. It is about providing. [Means for Solving the Problems] The rare earth magnet of the present invention is made by magnetizing a magnet material cut out from a hot isostatic press body or a hot extrusion press body of R-Fe-B permanent magnet alloy powder. , the surface is coated with a rust-resistant metal used as a container during the above-mentioned processing. In the above system, R is an la-based rare earth element represented by Nd. This magnet contains a small amount of Go. Substances to improve the performance of 11 stones such as DV203, Ga, Ni, Zn, Pb, A, I! Corrosion resistance, such as
It may contain substances to improve heat resistance and processability. "Rust-resistant metal" means a metal that does not easily rust in comparison with R-Fe-B permanent magnet alloys, and stainless steel is a typical example, but mild steel, silicon steel,
Fe-Ni alloy (36% Ni-Fe, 42% Ni −
Fe), Fe-Ni-C. Alloy (29%Ni-17%Co-Fe >, Fe
-Al-based alloy (Fe-13%AM), copper, copper-based alloy, aluminum, aluminum-based alloy, Ti alloy, etc. are also included. Typical examples of the rare earth magnet of the present invention are shown in Figures 1 and 2.
It is a ring-shaped rare earth magnet as shown in the figure. This magnet (1) is cut from a cylindrical hot-extruded press body, has magnetic anisotropy in the radial direction, and is made of a rust-resistant metal such as 5US304 stainless steel (for example, 5US304 stainless steel). 2A, 2B). The method for manufacturing rare earth magnets of the present invention involves filling R-Fe-B permanent magnet alloy powder into a rust-resistant metal can, sealing it under vacuum suction, and hot isostatic pressing at a temperature of 500°C or higher. Alternatively, a high-density sintered body is obtained by hot extrusion pressing, cut into a predetermined size to obtain a magnet material having a rust-resistant metal coating on the surface, and then magnetized. When filling the powder with hot isostatic pressing in Shun's sintering process, a product with a density of 95% or more can be obtained if the bulk density is 30% or more of the true density, but in the case of hot extrusion. requires a packing density of 50% or more. In any case, it is desirable to pack as densely as possible. The following methods are available for this. The simplest method is the vibration filling method, in which the powder is charged into the can while being photographed, and the theoretical density ratio is approximately 5.
5% filling is possible. Another method is to cold press the powder charged in a can, by applying a pressure of 3 to 7 tons/d.
It is possible to fill 80% of the theoretical density. Moreover, if cold isostatic pressing is performed, 85% filling is possible. To obtain the highest packing density, the magnetic alloy powder may be placed in a can and heated to 500-800° C. under vacuum at less than 10' Torr or under an inert gas atmosphere and hot pressed. As a result, the theoretical density ratio reaches 95%. It is also good to cold compact the magnetic alloy powder prior to hot pressing. The can filled with magnetic alloy powder by any of the above methods is covered and attached by a method such as welding. In the case of vibration filling, it is also possible to fill the container with the lid on. The filling body thus prepared is then placed in a vacuum chamber to degas it, and then the opening is welded and sealed by electron beam welding or the like to form a can seal. The degree of vacuum at this time is 10'
It is desirable that the pressure be reduced to Torr or stronger. The can body is then hot isostatically pressed or hot extrusion pressed. In the latter case, the material is first heated to raise the temperature to the processing temperature. This can of course be done in the atmosphere. The temperature needs to be 500° C. or higher in view of deformability; if it is lower than that, processing cracks are likely to occur and magnetic anisotropy cannot be obtained. Furthermore, at temperatures exceeding 800° C., crystal grains grow significantly and the magnetic properties are impaired. Taking all of these into account, a range of 700 to 750°C is optimal. The heating time should be kept as short as possible to avoid crystal grain growth. Therefore, it is preferable that the heating means be one that can quickly raise the temperature, such as high-frequency induction or energization. To obtain a ring-shaped magnet with high radial anisotropy, hot forward or submerged extrusion pressing is performed using a can with a cylindrical interior. This hot extrusion press is preferably carried out under conditions where hydrostatic pressure is applied. FIG. 3 shows this process being carried out on the hollow can body obtained as described above. The heated can sealing body 3 is housed in the container 5, and the die 8A and the mandrel 8 are pressed by the stem 6 (in the direction of the arrow from above in the figure).
This is formed between B and becomes a pipe 9 and is extruded (downward in the figure). If a medium 7 that is viscous and incompressible at the processing temperature, such as heat-resistant grease, is sealed in the container 5 to seal the joint of the mold, the space volume inside the container will be reduced by the movement of the stem 6. As a result, high hydrostatic pressure is generated within the medium. This hydrostatic pressure acts as a compressive stress on the entire surface of the can sealing body 3, and can prevent cracking due to its deformation. The height of the hydrostatic pressure in this case is 3,000 to 10,
'j/ai is suitable for 000; at a pressure lower than this, the effect of preventing cracking is poor, and at a pressure higher than this, the strength of the mold will not be able to withstand it. Ring-shaped magnets are often used, for example, when used in the rotor of a motor, by attaching a shaft, a power transmission material, or a magnetic circuit forming material. Such parts can also be attached by inserting them into the can sealing body to form a ring during hot isostatic pressing, or by inserting them into the extrusion press body during hot extrusion pressing.
上記の熱間加工によって得た焼結体は、これを所定の寸
法に切断して磁化することにより、所望の高性能磁石が
得られる。 焼結体が棒状体であればその外周、筒状体
であれば外周および内周が、加工の際の容器として用い
た錆びにくい金属で被覆されている。 切断面は露出し
ているので、塗装、メツキそのほか、常用の防錆手段を
施すとよい。 本発明のｍ石の代表であるリング状磁石
は、多くの用途にお９）で切断面の少なくとも一方がケ
ーシングに密着させられ、その面はふつう防錆処理を必
要としないであろう。
熱間加工により、色材料は磁石合金粉末に強く押しつけ
られ接合しているから、通常は切断後も被覆がそのまま
残る。 しかし、被覆の強い接合がとくに重要な場合は
、缶の材料をそれに応じて選択すべきであろう。 とい
うのは、Ｒ−Ｆｅ−Ｂ系永久磁石合金は線膨張率が小さ
く、とくに塑性加工により磁気異方性を与えたときの磁
化容易軸に垂直の方向には、室温かうキュリー点までの
間はマイナスの値を示すからであって、これは上記した
リング状磁石の製造において、熱間加工時より冷却時の
方が内径が拡大する傾向のあることを意味する。
缶の材料として挙げたステンレス鋼、軟ｍおよびケイ素
鋼は、いずれも線膨張率が比較的大きいから、それでリ
ングの外周を被覆したときは、冷却時に磁石をしめつけ
ることになって、接合は強固である。 内周の被覆を強
固にするには、線膨張率がごく小ざい材料、たとえばイ
ンバー合金、４２％Ｎｉ材、コバールなど、ざらには線
膨張率がマイナスのものをえらべばよい。
被覆を形成する缶の材料を選択するに当っては、そのほ
かに、リングに関する磁気回路形成の態様、つまり内側
と外側のどちらに磁気回路を形成するかをも考慮すべき
である。 磁気回路に関与する側は磁性材料が好ましい
ことはもちろんであり、関与しない側はむしろ非磁性材
料が好適である。
場合により、缶の材料を一部取り外すのであれば、銅ま
たは銅基合金のように、変形抵抗の小さい材料を用いる
と、取り外しに際して磁石材料が割れたりする危険が避
けられる。The sintered body obtained by the above hot working is cut into predetermined dimensions and magnetized to obtain a desired high-performance magnet. If the sintered body is a rod-shaped body, its outer circumference, and if it is a cylindrical body, its outer circumference and inner circumference are coated with a rust-resistant metal used as a container during processing. Since the cut surface is exposed, it is a good idea to paint, plate, or use other commonly used anti-corrosion measures. In many applications, at least one of the cut surfaces of the ring-shaped magnet, which is representative of the m-stone of the present invention, is brought into close contact with the casing, and that surface generally does not require anti-rust treatment. Because the colored material is strongly pressed and bonded to the magnetic alloy powder through hot working, the coating usually remains intact even after cutting. However, if strong bonding of the coating is particularly important, the can material should be selected accordingly. This is because the R-Fe-B permanent magnet alloy has a small coefficient of linear expansion, especially in the direction perpendicular to the axis of easy magnetization when magnetic anisotropy is imparted through plastic working, from room temperature to the Curie point. indicates a negative value, which means that in manufacturing the above-mentioned ring-shaped magnet, the inner diameter tends to expand during cooling than during hot working. Stainless steel, soft metal, and silicon steel, all of which are mentioned as materials for cans, have relatively large coefficients of linear expansion, so when the outer periphery of the ring is coated with them, the magnet tightens during cooling, making the joint strong. It is. In order to strengthen the inner periphery coating, it is sufficient to select a material with a very small coefficient of linear expansion, such as an invar alloy, 42% Ni material, Kovar, etc., which generally has a negative coefficient of linear expansion. In selecting the material for the can that forms the coating, consideration should also be given to the manner in which the magnetic circuit is to be formed with respect to the ring, ie, whether the magnetic circuit is to be formed on the inside or the outside. Of course, the side that participates in the magnetic circuit is preferably made of magnetic material, and the side that does not participate is preferably made of non-magnetic material. If some of the can material is to be removed, a material with low deformation resistance, such as copper or copper-based alloys, may be used to avoid the risk of cracking the magnet material during removal.
３０％Ｎｄ−１％Ｐｒ−０，８％Ｂ−０．２％Ｇａ−５
％Ｃｏ−残部Ｆｅからなる希土類磁石合金の急冷薄帯を
粉末化したものを用意し、これを肉厚２ｓの５ＵＳ３０
４ステンレス鋼でつくった、外管径７０ｓ＋Ｘ内管径２
５＃１ＩＩＸ長ざ１８０＃ｌの円筒状の缶の中に、撮動
充填法により充填して、真空中の電子ビーム溶接により
缶を密封した。 充填体のカサ密度は、真密度の約５０
％であった。
この缶封体を７００℃の炉の中に入れて２時間保持した
のち取り出し、第１図に示すような前方静水圧押出し法
により、外径３０ｍＸ内径２０ｍのバイブ状に成形した
。 このときの製品の押出し速度は、約１６０ｍ／秒で
めった。
パイプを切断して、第１図および第２図に示すような、
外側と内側を色材料の５ＵＳ３０４が被覆した、外径３
０履Ｘ内径２０！Ｍ１×厚さ１０ｍの。
リング状磁石材料を得た。 比較のため、リングの内面
および外面を２ａｍずつ切削して５ＵＳ３０４の層を除
去し、外径２８Ｍ×内径２２＃１ＩｌｆＸ厚ざ１０ｍの
リングをも得た。
これらの磁石材料はラジアル方向に磁気異方性を有し、
最大エネルギー積（ＢＨ）Ｉ１１８ｘが３０ＭＧＯｅ
、保磁力ｉＨｃが８，１００エルステツドの磁気特性を
示した。
上記２種のリングの耐食性をしらべるため、温度５０℃
、湿度９６％の環境に９６時間装いた。
比較例の磁石は全面に赤錆が発生して保磁力が４０％低
下したのに対し、本発明の磁石が錆びたのは切断面だけ
で、保磁力の低下は３％に止まった。30%Nd-1%Pr-0.8%B-0.2%Ga-5
A quenched ribbon of a rare earth magnetic alloy consisting of %Co and the balance Fe was prepared as a powder, and this was pulverized into a powder of 5US30 with a wall thickness of 2s.
4Made of stainless steel, outer tube diameter 70s + x inner tube diameter 2
A cylindrical can with a length of 5 #1 IIX and a length of 180 #l was filled by the imaging filling method, and the can was sealed by electron beam welding in a vacuum. The bulk density of the packing is approximately 50% of the true density.
%Met. This can sealing body was placed in a 700° C. furnace and held for 2 hours, then taken out and formed into a vibrator shape with an outer diameter of 30 m and an inner diameter of 20 m by forward isostatic extrusion as shown in FIG. The extrusion speed of the product at this time was approximately 160 m/sec. Cut the pipe and make it as shown in Figures 1 and 2.
Outer diameter 3, coated with colored material 5US304 on the outside and inside
0 shoes x inner diameter 20! M1 x thickness 10m. A ring-shaped magnet material was obtained. For comparison, the 5US304 layer was removed by cutting the inner and outer surfaces of the ring by 2 am to obtain a ring with an outer diameter of 28 M x inner diameter of 22 #1 Ilf x thickness of 10 m. These magnet materials have magnetic anisotropy in the radial direction,
Maximum energy product (BH) I118x is 30MGOe
It exhibited magnetic properties with a coercive force iHc of 8,100 oersteds. In order to examine the corrosion resistance of the above two types of rings, the temperature was 50℃.
, and was placed in an environment with 96% humidity for 96 hours. In the magnet of the comparative example, red rust occurred on the entire surface and the coercive force decreased by 40%, whereas in the magnet of the present invention, rust occurred only on the cut surface, and the decrease in coercive force was limited to 3%.
本発明のＲ−Ｆｅ−Ｂ系希土類磁石は、その表面に強固
に接合した錆びにくい金属の被覆があるから、この磁石
合金の弱点であった錆びやすさが改善されている。 と
くにこの種の磁石の代表であるリング状磁石におい又は
、磁気回路を形成するリング外周または内周に被覆があ
って錆びが防止できるから、僅少の磁気回路ギャップに
おいて錆が生じてトラブルをひきおこすことはなくなる
。
切断面は、必要に応じて防錆処理を施せばよい。
磁石の外周に、場合によってはざらに内周にも金属の被
覆があることは、そこへ他の部品すなわち動力伝達部材
や磁気回路形成部材を装着するときにも、有利である。
このような希土類磁石を与える本発明の製造方法は、Ｒ
−Ｆｅ −Ｂ系磁石合金の弱点であった易酸化性や難加
工性に伴う問題が回避でき、とくに熱間押出しプレス、
好ましくは熱間静水圧押出しプレスによる場合は、大気
中で１工程の塑性変形を行なうことによって、ワレの発
生を防いで、所望の寸法の成形品を）ｑることができる
。 従ってこの方法は、とくに小径の磁石、薄肉の磁石
を製造するのに適している。Since the R-Fe-B rare earth magnet of the present invention has a rust-resistant metal coating firmly bonded to its surface, the susceptibility to rust, which was a weak point of this magnet alloy, has been improved. In particular, since ring-shaped magnets, which are typical of this type of magnet, or the outer or inner periphery of the ring that forms the magnetic circuit are coated to prevent rust, rust can occur in small gaps in the magnetic circuit and cause trouble. will disappear. The cut surface may be subjected to anti-rust treatment if necessary. Having a metal coating on the outer periphery of the magnet, and in some cases even on the inner periphery, is advantageous when other parts, such as a power transmission member or a magnetic circuit forming member, are attached thereto. The manufacturing method of the present invention provides such a rare earth magnet, R
Problems associated with easy oxidation and difficult workability, which were weaknesses of -Fe -B magnetic alloys, can be avoided, and it is especially suitable for hot extrusion presses.
Preferably, when using a hot isostatic extrusion press, one step of plastic deformation is performed in the atmosphere, thereby preventing cracking and making it possible to form a molded product with desired dimensions. Therefore, this method is particularly suitable for manufacturing small-diameter magnets and thin-walled magnets.
第１図および第２図は、ともに本発明の希土類磁石の一
例を示すものであって、第１図は平面図、第２図は縦断
面図である。
第３図は、本発明の希土類磁石の製造方法の好ましい態
様を示すものであって、缶封体を熱間静水圧押出しプレ
スによりパイプに成形しているところを示す縦断面図で
おる。
１・・・ｆ！１５合金
２Ａ、２Ｂ・・・被 覆
３・・・缶封体
５・・・コンテナー ６・・・ステム７・・・媒
体
８Ａ・・・ダ イ ８Ｂ・・・マンドレル９・
・・パイプ
特許出願人 大同特殊鋼株式会社
代理人 弁理士 須 賀 総 夫
第１図 第２図
第３図1 and 2 both show an example of the rare earth magnet of the present invention, with FIG. 1 being a plan view and FIG. 2 being a longitudinal sectional view. FIG. 3 shows a preferred embodiment of the method for manufacturing a rare earth magnet of the present invention, and is a longitudinal cross-sectional view showing a can seal being formed into a pipe by hot isostatic extrusion pressing. 1...f! 15 alloy 2A, 2B...Coating 3...Can seal 5...Container 6...Stem 7...Medium 8A...Die 8B...Mandrel 9.
...Pipe patent applicant Daido Steel Co., Ltd. Agent Patent attorney Souo Suga Figure 1 Figure 2 Figure 3
Claims (8)
れす。）永久磁石合金の粉末の熱間静水圧プレス体また
は熱間押出しプレス体から切り出した磁石材料を磁化し
てなり、表面が上記加工の際の容器として用いた錆びに
くい金属で被覆されていることを特徴とする希土類磁石
。(1) R-Fe-B type (R stands for La-based rare earth element) magnet material cut from a hot isostatically pressed body or a hot extrusion pressed body of permanent magnet alloy powder. A rare earth magnet, the surface of which is coated with a rust-resistant metal used as a container during the above processing.
グ状磁石であって、ラジアル方向に磁気異方性を有し、
リングの内側および（または）外側が上記の錆びにくい
金属で被覆されている請求項１の希土類磁石。(2) A ring-shaped magnet cut from a cylindrical hot extrusion press body, which has magnetic anisotropy in the radial direction,
The rare earth magnet according to claim 1, wherein the inside and/or outside of the ring is coated with the above-mentioned rust-resistant metal.
回路形成材を装着した請求項２の希土類磁石。(3) The rare earth magnet according to claim 2, wherein a power transmission material or a magnetic circuit forming material is attached to the inside or outside of the ring.
０℃において−２．０〜５．０×１０＾−＾６／℃であ
るものを使用した、請求項１ないし３のいずれかの希土
類磁石。(4) As a rust-resistant metal, it has a coefficient of thermal expansion of 30 to 20.
4. The rare earth magnet according to claim 1, wherein the rare earth magnet has a temperature of -2.0 to 5.0 x 10^-^6/[deg.]C at 0[deg.]C.
金属の缶内に充填して真空吸引下に密封し、５００℃以
上の温度で熱間静水圧プレスまたは熱間押出しプレスし
て高密度の焼結体とし、所定の寸法に切断して表面に錆
びにくい金属の被覆を有する磁石材料を得、これを磁化
することからなる希土類磁石の製造方法。(5) R-Fe-B permanent magnet alloy powder is filled into a rust-resistant metal can, sealed under vacuum suction, and hot isostatically pressed or hot extruded at a temperature of 500°C or higher. A method for manufacturing a rare earth magnet, which comprises making a high-density sintered body, cutting it into predetermined dimensions to obtain a magnet material having a rust-resistant metal coating on the surface, and magnetizing the same.
のを使用し、熱間押出しプレスを行なってラジアル方向
の磁気異方性を与える請求項５の製造方法。(6) The manufacturing method according to claim 5, wherein a rust-resistant metal can with a cylindrical interior is used, and hot extrusion pressing is performed to impart magnetic anisotropy in the radial direction.
う請求項６の製造方法。(7) The manufacturing method according to claim 6, wherein hot isostatic extrusion is performed as the hot extrusion press.
て、リングの内側または外側に、動力伝達材または磁気
回路形成材を装着させる請求項５の製造方法。(8) The manufacturing method according to claim 5, wherein a power transmission material or a magnetic circuit forming material is attached to the inside or outside of the ring during hot isostatic pressing or hot extrusion pressing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9054888A JPH01261806A (en) | 1988-04-13 | 1988-04-13 | Rare earth magnet and its manufacture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9054888A JPH01261806A (en) | 1988-04-13 | 1988-04-13 | Rare earth magnet and its manufacture |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01261806A true JPH01261806A (en) | 1989-10-18 |
Family
ID=14001468
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9054888A Pending JPH01261806A (en) | 1988-04-13 | 1988-04-13 | Rare earth magnet and its manufacture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01261806A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005243882A (en) * | 2004-02-26 | 2005-09-08 | Shin Etsu Chem Co Ltd | Rare earth magnet sealing body and manufacturing method thereof |
| US20090044589A1 (en) * | 2004-03-11 | 2009-02-19 | Gkss-Forschumgszentrum Geesthacht Gmbh | Method for the production of profiles of a light metal material by means of extrusion |
| CN107000051A (en) * | 2014-08-15 | 2017-08-01 | 城市矿业公司 | Grain boundary engineering |
| WO2023034887A1 (en) * | 2021-09-01 | 2023-03-09 | Stereotaxis, Inc. | Drawn filled tubing magnets, and methods, devices, and systems related thereto |
-
1988
- 1988-04-13 JP JP9054888A patent/JPH01261806A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005243882A (en) * | 2004-02-26 | 2005-09-08 | Shin Etsu Chem Co Ltd | Rare earth magnet sealing body and manufacturing method thereof |
| JP4583048B2 (en) * | 2004-02-26 | 2010-11-17 | 信越化学工業株式会社 | Rare earth magnet sealed body and method of manufacturing IPM motor |
| US20090044589A1 (en) * | 2004-03-11 | 2009-02-19 | Gkss-Forschumgszentrum Geesthacht Gmbh | Method for the production of profiles of a light metal material by means of extrusion |
| US8590356B2 (en) * | 2004-03-11 | 2013-11-26 | Helmholtz-Zentrum Geesthacht Zentrum für Material- und Küstenforschung GmbH | Method for the production of profiles of a light metal material by means of extrusion |
| CN107000051A (en) * | 2014-08-15 | 2017-08-01 | 城市矿业公司 | Grain boundary engineering |
| WO2023034887A1 (en) * | 2021-09-01 | 2023-03-09 | Stereotaxis, Inc. | Drawn filled tubing magnets, and methods, devices, and systems related thereto |
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