JPH07101644B2 - Anisotropic manganese-aluminum-carbon permanent magnet and method for producing the same - Google Patents

Description

【発明の詳細な説明】 産業上の利用分野 本発明は、永久磁石とその製造法に関するもので、詳細
には多結晶の異方性マンガン−アルミニウム−炭素系永
久磁石（以下異方性Mn-Al-C系永久磁石と略称）とその
製造法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet and a method for producing the same, and more specifically, a polycrystalline anisotropic manganese-aluminum-carbon permanent magnet (hereinafter referred to as anisotropic Mn- Al-C permanent magnet) and its manufacturing method.

従来の技術 Mn-Al-C系永久磁石は、主として強磁性相である面心正
方晶の結晶組織で構成され、Ｃを必須構成元系として含
むもので不純物以外に添加元素を含まない３元系及び少
量の添加元素を含む４元系以上の多元系合金磁石が知ら
れており、これらを総称するものである。2. Description of the Related Art Mn-Al-C permanent magnets are mainly composed of a face-centered tetragonal crystal structure, which is a ferromagnetic phase, and contain C as an essential constituent element system. A quaternary or higher multi-component alloy magnet containing a system and a small amount of additional elements is known, and these are collectively referred to.

従来このMn-Al-C系永久磁石は、Mn65-74重量パーセント
（以下単にwt％と記す）、Al25〜34wt％、炭素4wt％以
下の組成の鋳造合金に適切な熱処理を施された場合、最
大磁気エネルギー積（Ｂ・Ｈ）_max＝1.0〜1.6MG・Oeの
磁気特性を有する永久磁石として知られている。Conventionally, this Mn-Al-C-based permanent magnet has a Mn65-74 weight percent (hereinafter simply referred to as wt%), Al25 to 34 wt%, and a cast alloy having a composition of carbon 4 wt% or less when subjected to an appropriate heat treatment, It is known as a permanent magnet having a magnetic property of maximum magnetic energy product (B · H) _max = 1.0 to 1.6 MG · Oe.

さらに、Mn68〜73wt％、炭素0.2〜2.1wt％、残部アルミ
ニウムの組成の鋳造材に適切な熱処理を施し、その後53
0℃〜830℃の温度領域で温間塑性加工されたMn-Al-C系
合金は、熱処理で得られる前記の合金磁石よりも数倍の
（Ｂ・Ｈ）_max値を有する磁気特性の優れた異方性永久
磁石として知られる。例えば多結晶異方性Mn-Al-C系磁
石では（Ｂ・Ｈ）_max＝５〜6.5MG・Oe、残留磁束密度Br
＝5200〜6000G、保磁力Hc＝2000〜2600Oe程度の磁気性
能を保有する（特公昭54-31448号公報、特公昭54-20166
号公報参照）。Further, a cast material having a composition of Mn 68 to 73 wt%, carbon 0.2 to 2.1 wt% and the balance aluminum is subjected to an appropriate heat treatment, and then 53
The Mn-Al-C alloys that have been warm plastically worked in the temperature range of 0 ° C to 830 ° C have several times (BH) _max values that are superior to those of the alloy magnets obtained by heat treatment and have excellent magnetic properties. Known as an anisotropic permanent magnet. For example, in the case of polycrystalline anisotropic Mn-Al-C magnet, (BH) _max = 5 to 6.5MGOe, residual magnetic flux density Br
= 5200 to 6000G, coercive force Hc = 2000 to 2600Oe, and possesses magnetic performance (Japanese Patent Publication No. 54-31448 and Japanese Patent Publication No. 54-20166).
(See the official gazette).

発明が解決しようとする問題点 しかし、最近の電子部品、電気製品の軽量薄形化指向に
対して、Mn-Al-C系磁石の磁気性能の内、特に保磁力Hc
をより高めることが強く要望されている。又、Mn-Al-C
系磁石の製造工程における温間塑性加工は、その加工圧
力が40〜70kg/mm²程度必要とし、この値は530〜830℃の
温間での条件下では一般の塑性加工における加工圧力に
比較して数十％高く、工具の寿命又はダイス構造等の制
約から、１回の温間塑性加工の加工率に制約があり、高
い磁気特性を得るための所定の加工率を達成するために
は数回の温間塑性加工を実施しなければならない。従っ
て、温間塑性加工における加工圧の低減化又は、同じ加
工率でより高い磁気特性が得られるような永久磁石又は
その製造法が望まれていた。Problems to be Solved by the Invention However, in view of the recent trend toward lightweight and thin electronic parts and electric products, among the magnetic performances of Mn-Al-C based magnets, especially the coercive force Hc
There is a strong demand for further improvement. Also, Mn-Al-C
Warm plastic working in the manufacturing process of magnetic magnets requires a working pressure of about 40 to 70 kg / mm ² , and this value is compared to the working pressure in general plastic working under conditions of a warm temperature of 530 to 830 ° C. It is several tens of percent higher, and there is a limit to the processing rate of one warm plastic working due to the tool life or the die structure etc., and in order to achieve the predetermined processing rate for obtaining high magnetic properties, Warm plastic working must be carried out several times. Therefore, there has been a demand for a permanent magnet or a manufacturing method thereof that can reduce the working pressure in the warm plastic working or obtain higher magnetic properties at the same working rate.

一方、Mn-Al-C系磁石の製造法としては、粉末治金法を
利用し、溶湯の急冷粉末又は前記の温間塑性加工後の材
料の粉砕粉末を冷間，成形，焼結，熱処理することが提
案されている（特開昭58-58241号公報，特開昭55-10094
4号公報参照）。On the other hand, as a method for manufacturing Mn-Al-C magnets, a powder metallurgy method is used, and quenching powder of molten metal or crushed powder of the material after the warm plastic working is cold-formed, sintered, heat-treated. Is proposed (Japanese Patent Laid-Open No. 58-58241 and Japanese Patent Laid-Open No. 55-10094).
(See Publication No. 4).

しかし、この方法においては、鋳造法による磁石に比較
して、その磁気特性は1/2以下で強度も低く実用磁石と
て普及していないのが実情である。However, in this method, the magnetic characteristics are less than 1/2 and the strength is low as compared with the magnet by the casting method, and it is the fact that it is not widely used as a practical magnet.

本発明は前述したように、磁気特性の特に保磁力を改善
し、かつ、より経済性に優れた異方性Mn-Al-C系永久磁
石とその製造法を提供するものである。As described above, the present invention provides an anisotropic Mn-Al-C based permanent magnet which has improved magnetic properties, particularly coercive force, and is more economical, and a method for producing the same.

問題点を解決するための手段 本発明者らは、前記問題点について種々実験を重ねた結
果、Mn-Al-C系永久磁石の合金組織を従来とは異なるも
のにすることによって大巾に改善することを見い出し
た。その技術的手段は、面心正方晶を主体とする塑性変
形された針状形状又は、円板形状粒子の集合体であり、
かつその針状形状の長軸方向が特定の方向に配列してお
り、又は円板形状の平面が互いに平行に配列している合
金組織にすることである。Means for Solving the Problems As a result of various experiments conducted on the above problems, the inventors of the present invention significantly improved the alloy structure of the Mn-Al-C based permanent magnet by making it different from the conventional one. I found out what to do. The technical means is a plastically deformed needle-shaped or mainly disk-shaped particles mainly composed of face-centered tetragonal crystals,
In addition, the long axis direction of the needle shape is arranged in a specific direction, or the alloy structure is such that the disk-shaped planes are arranged parallel to each other.

又、その製造法の特徴は、適切な組成のMn-Al-C系合金
の溶湯から溶湯急冷法等によって微細な粉末をつくり、
その粉末を530〜850℃の温度範囲の温度で圧縮成形して
成形体とし、この成形体を530〜780℃の温度で温間押出
加工，温間圧延等の温間塑性加工を施すことにより、成
形体内粒子を針状又は、円板状に変形配列させ、強固な
その集合体とするものである。In addition, the characteristic of the manufacturing method is that a fine powder is produced from a melt of Mn-Al-C alloy having an appropriate composition by a melt quenching method,
The powder is compression molded at a temperature in the range of 530 to 850 ℃ to form a molded body, and this molded body is subjected to warm plastic working such as warm extrusion and warm rolling at a temperature of 530 to 780 ℃. The particles in the formed body are deformed and arranged in a needle shape or a disk shape to form a strong aggregate.

作用 上記構成とすることにより、最大磁気エネルギー積が向
上し、保磁力の優れた、しかも小型で生産性に優れた異
方性Mn−Al−Ｃ系永久磁石が提供できることになる。Action With the above configuration, it is possible to provide an anisotropic Mn-Al-C based permanent magnet having an improved maximum magnetic energy product, an excellent coercive force, a small size, and an excellent productivity.

実施例 以下、本発明の実施例を説明する。Examples Hereinafter, examples of the present invention will be described.

Mn-Al-C系合金の溶湯から溶湯急冷法等によって作成し
た粉末をその平均粒径が400μｍ以下のものを所定量測
りとり、例えば成形温度600℃、成形圧力30kg/mm²にて
圧縮成形すれば、ほぼ100％充填された粉末成形材が得
られる。この成形材は多角形状に塑性変形されて相互に
密着した粒子の集合体となっており、粒子の破壊、粒子
間の亀裂等の欠陥は、ほとんどなく従来の粉末成形とそ
の焼結材に比較して機械的強度に優れたものである。こ
の粉末成形材を、さらに特定の方向に温間塑性加工を行
い、第１図の顕微鏡写真に示すように粉末粒子を針状又
は円板状に塑性変形させかつその針状の長軸方向を軸方
向に配列させること及び円板形状にあってはその平面を
互いに平行に配列させることによって極めて優れた異方
性永久磁石を得ることに成形した。温間押出加工後にお
けるその磁気特性を従来の鋳造材の製造法によるものと
比較すると、Brは、ほぼ同等であるがHcは4500〜4600Oe
であり約80％の大巾な向上が得られ、又、（Ｂ・Ｈ）
_max＝7.8〜7.9MG・Oeで、約20％向上した。A predetermined amount of powder with an average particle size of 400 μm or less is measured from powder of Mn-Al-C alloy melt by the melt quenching method, and compression molding is performed at a molding temperature of 600 ° C and a molding pressure of 30 kg / mm ² , for example. By doing so, a powder molded material that is almost 100% filled can be obtained. This molded material is an aggregate of particles that are plastically deformed into a polygonal shape and adhere to each other, and there are almost no defects such as particle breakage and cracks between particles, compared to conventional powder molding and its sintered material. It has excellent mechanical strength. This powder molding material is further subjected to warm plastic working in a specific direction to plastically deform the powder particles into a needle shape or a disk shape as shown in the micrograph of FIG. By arranging in the axial direction and in the case of a disc shape, the planes thereof are arranged in parallel to each other, it was molded to obtain an extremely excellent anisotropic permanent magnet. Comparing the magnetic properties after warm extrusion with those of the conventional casting material manufacturing method, Br is almost the same but Hc is 4500-4600 Oe.
And a significant improvement of about 80% was obtained, and (B ・ H)
_{With max} = 7.8-7.9MG Oe, it improved by about 20%.

Hcと（Ｂ・Ｈ）_maxの向上の機構は、温間塑性加工後の
合金磁石の顕微鏡観察によれば、従来の鋳造材を用いた
製造法の合金磁石の場合に比較して、本発明の永久磁石
は粉末粒子の集合体を塑性加工するため、加工圧力は粒
子全体に比較的均一に及び、ほぼすべての粒子が針状又
は円板状に均質に特定方向に整列して塑性変形すること
によるものと考えられる。According to a microscope observation of the alloy magnet after the warm plastic working, the mechanism of the improvement of Hc and (B · H) _max is as compared with the case of the alloy magnet of the manufacturing method using the conventional casting material. Since the permanent magnet of No. 1 plastically processes the aggregate of powder particles, the processing pressure is relatively uniform over the whole particles, and almost all particles are plastically deformed in a needle-like or disk-like uniform alignment in a specific direction. It is thought that this is due to a matter.

さらに本発明によれば、温間塑性加工においる加工率と
磁気特性の関係は、従来の鋳造法によるものに比較し同
一加工率のもとで、（Ｂ・Ｈ）_maxで20〜80％、Hcで70
〜80％もの向上を示す。これは、前記の向上機構が、低
加工率においても有効に作用しているためと考えられ
る。Further, according to the present invention, the relationship between the working rate and the magnetic characteristics in the warm plastic working is 20 to 80 at (BH) _max under the same working rate as compared with the conventional casting method. %, Hc 70
Shows ~ 80% improvement. It is considered that this is because the above-mentioned improvement mechanism works effectively even at a low processing rate.

以上のような各種の作用は、後に詳述するように、粉末
粒子の粒度によってある程度限定され、実験結果によれ
ばその平均直径が400μｍ以下で、特に本発明の効果が
大きい。以下具体的な実施例によりさらに本発明を詳述
する。As will be described in detail later, the various actions as described above are limited to some extent by the particle size of the powder particles, and according to the experimental results, the average diameter is 400 μm or less, and the effect of the present invention is particularly great. The present invention will be described in more detail below with reference to specific examples.

〔実施例１〕 Mn69wt％、C0.5wt％、Al残部よりなる組成を溶解し、ア
トマイズ法にてMn-Al-C合金の粉末を作成した。粉末形
状は球状で粒子の平均直径は、およそ600μｍ以下であ
り、粒度選別によって400μｍ以下のものを抽出した。
尚、この粒子の相状態はＸ線回折によって調べた結果、
ε相（非磁性六方晶）が主体であった。この粉末を所定
量計量後、ダイスに投入し油圧プレスにて温度600℃、
圧力30kg/mm²の条件で圧縮成形した。[Example 1] A composition of Mn 69 wt%, C 0.5 wt% and the balance of Al was melted, and Mn-Al-C alloy powder was prepared by an atomizing method. The powder has a spherical shape and the average diameter of the particles is about 600 μm or less, and particles having a diameter of 400 μm or less were extracted by particle size selection.
The phase state of the particles was examined by X-ray diffraction,
The ε phase (nonmagnetic hexagonal crystal) was the main component. After measuring a certain amount of this powder, put it into a die and press the hydraulic press at a temperature of 600 ° C.
Compression molding was performed under a pressure of 30 kg / mm ² .

得られたφ30×^l30の粉末成形ビレットの顕微鏡観察及
び電子顕微鏡観察によれば、第２図に示すように粉末粒
子は多角形状に塑性変形して、粒子相互は密着してい
た。According to microscopic observation and electron microscopic observation of the powder molding billet obtained 0 30 × ^l 30, the powder particles as shown in FIG. 2 is plastically deformed into a polygonal shape, the particles each other have been in close contact.

又、その相状態をＸ線回折により調べた結果、面心正方
晶（τ相＝強磁性相）を主体とした等方性磁石であっ
た。その磁気特性は（Ｂ・Ｈ）_max＝2.1MG・Oeで等方性
磁石として使用できる十分な磁気特性をもっていた。As a result of examining the phase state by X-ray diffraction, it was an isotropic magnet mainly composed of a face-centered tetragonal crystal (τ phase = ferromagnetic phase). The magnetic properties were (BH) _max = 2.1MGOe, which was sufficient for use as an isotropic magnet.

前記の粉末成形ビレットを温度700℃でビレットの軸方
向に温間押出加工を実施しφ16.5×99の棒材を得た。押
出比Ｒ（押出加工前後のビレットの断面積比）は、3.3
とした。押出加工後の棒材の顕微鏡観察によれば、その
合金組織は、第１図に示すように従来の鋳造材の温間押
出後の棒材には観察されないような針状形状の粒子が集
合しており、又、その針状形状の長軸は押出材の軸方向
（押出方向）に整列していた。The powder molding billet was warm extruded in the axial direction of the billet at a temperature of 700 ° C. to obtain a bar material of φ16.5 × 99. The extrusion ratio R (the cross-sectional area ratio of the billet before and after extrusion) is 3.3.
And According to the microscopic observation of the bar material after extrusion, the alloy structure is such that, as shown in Fig. 1, acicular particles that are not observed in the bar material of the conventional cast material after warm extrusion are aggregated. Further, the long axis of the needle-like shape was aligned in the axial direction (extrusion direction) of the extruded material.

温間押出後の棒材から、押出方向に垂直な面と押出方向
に平行な面を有する一辺が10mmの立方体試料を切り出
し、磁気特性を測定した。その結果、押出方向に垂直の
方向では、（Ｂ・Ｈ）_max＝0.5MG・Oeと低い値であった
が押出方向では、（Ｂ・Ｈ）_max＝5.6MG・Oeの高い磁気
特性を示し、粉末粒子の針状形状の長軸方向に磁化容易
方向を有する優れた異方性永久磁石となった。又、残留
磁束密度は、Br＝5600G、保磁力はHc＝3200Oeを示し
た。特にこのHcの値は、従来の異方性Mn-Al-C系磁石の
保磁力に比較して同一レベルの（Ｂ・Ｈ）_maxのもとで
約50％もの向上率を示した。A cubic sample having a surface perpendicular to the extrusion direction and a surface parallel to the extrusion direction and having a side of 10 mm was cut out from the bar after the warm extrusion, and the magnetic properties were measured. As a result, the value perpendicular to the extrusion direction was as low as (B · H) _max = 0.5MG · Oe, but in the extrusion direction, it showed high magnetic properties of (B · H) _max = 5.6MG · Oe. It became an excellent anisotropic permanent magnet having an easy magnetization direction in the major axis direction of the acicular shape of powder particles. The residual magnetic flux density was Br = 5600G and the coercive force was Hc = 3200Oe. In particular, this Hc value showed an improvement rate of about 50% under the same level of (BH) _max as compared with the coercive force of the conventional anisotropic Mn-Al-C magnet.

さらに前記の温間押出後の棒材の引張強度を測定した結
果、26kg/mm²の値を示し、従来の鋳造法による温間押出
材に匹敵した。Further, the tensile strength of the bar material after the warm extrusion was measured, and as a result, it showed a value of 26 kg / mm ² , which was comparable to that of the conventional warm extrusion material by the casting method.

〔実施例２〕 実施例１と同様の方法で作成した30mm×30mm×30mmの粉
末成形ビレットを圧延ローラを用いて一方向の圧縮加工
を実施した。温度600℃で熱間用圧延ローラを用い、加
工率（圧縮の加工前後の厚さの減少割合）Ｋ・Ｒ＝41％
にて平板材を得た。この顕微鏡組織は圧延の平板面と平
行な面では、粉末粒子は長円形、圧延面に直角で、圧延
方向に平行な面では粉末粒子は薄板状で相互に平行に整
列していた。Example 2 A 30 mm × 30 mm × 30 mm powder molding billet prepared by the same method as in Example 1 was subjected to unidirectional compression processing using a rolling roller. Using a hot rolling roller at a temperature of 600 ° C, processing rate (rate of reduction in thickness before and after compression) KR = 41%
A flat plate material was obtained. In this microstructure, the powder particles were oval on the plane parallel to the flat plate surface of the rolling, the powder particles were perpendicular to the rolling surface, and the powder particles were thin plate-shaped and aligned parallel to each other on the surface parallel to the rolling direction.

得られた平板材から一辺が10mmの立方体試料を、その相
対する面が圧延方向と直角になるように切り出し、磁気
特性を測定した結果、圧延の方向に異方性化しており
（Ｂ・Ｈ）_max＝5.3MG・Oe、Br＝5200G、Hc＝3500Oeで
特に大きなHcを示した。A cubic sample with a side of 10 mm was cut from the obtained flat plate material so that the opposite surface was perpendicular to the rolling direction, and the magnetic properties were measured. As a result, it was anisotropy in the rolling direction (BH ) _Max = 5.3MG Oe, Br = 5200G, and Hc = 3500Oe, with a particularly large Hc.

以上、実施例1,2によって明らかなように、Mn-Al-C系の
合金粉末が、温間塑性加工によってその形状が、針状化
又は、円板状化された集合体であって、針状形状にあっ
てはその長軸方向が、軸方向に整列していること、及び
円板形状にあっては、円板の平面が互いに平行に整列し
ていることによって、各々その特定方向に磁化容易方向
を有する優れた異方性磁石が得られることが判明した。As described above, as is clear from Examples 1 and 2, the Mn-Al-C alloy powder has a shape by warm plastic working, and is a needle-shaped or disk-shaped aggregate. In the needle-like shape, the major axis direction is aligned in the axial direction, and in the disk shape, the planes of the disks are aligned parallel to each other, so that It was found that an excellent anisotropic magnet having an easy magnetization direction can be obtained.

〔実施例３〕 実施例１の方法（温間粉末成形とその後の温間押出加
工）において、温間押出加工における押出比Ｒ＝6.1と
し、合金の組成値を種々設定し、加工後に得られる磁気
特性を調べた。[Example 3] In the method of Example 1 (warm powder molding and subsequent warm extrusion processing), the extrusion ratio R in warm extrusion processing was set to 6.1, various composition values of the alloy were set, and obtained after processing. The magnetic properties were investigated.

その結果を第３図に示す。磁気特性はMn値67〜73wt％及
びＣ値0.2〜2.1wt％、Al残部の組成範囲においては高い
磁気特性を示した。特にMn69.3wt％、C0.5wt％、残部Al
よりなく組成においては（Ｂ・Ｈ）_max＝7.7MG・Oe、Hc
＝4400Oe、Br＝6200Gの最高性能を示した。The results are shown in FIG. The magnetic properties were such that the Mn value was 67 to 73 wt% and the C value was 0.2 to 2.1 wt%, and high magnetic properties were exhibited in the composition range of the balance of Al. Especially Mn69.3wt%, C0.5wt%, balance Al
(B ・ H) _max = 7.7 MG ・ Oe, Hc
＝ 4400Oe, Br ＝ 6200G.

又、Mn69.3wt％で磁気特性のピーク値を示す傾向は、従
来の鋳造法による磁石での傾向（Mn70.0wt％で磁気特性
のピーク値を示す）と異なり、Mn組成値で0.7wt％のシ
フトを示した。これは、本発明の粉末粒子の温間塑性加
工によって得られた合金組織上の特異性か現れたものと
考えられる。In addition, the tendency of the magnetic property peak value at Mn 69.3 wt% is 0.7 wt% at the Mn composition value unlike the tendency of the magnet by the conventional casting method (Mn 70.0 wt% shows the magnetic property peak value). Showed a shift. It is considered that this is due to the peculiarity on the alloy structure obtained by the warm plastic working of the powder particles of the present invention.

〔実施例４〕 実施例１と同じ組成のアトマイズ法による粉末粒子の平
均直径を600μｍ以上、600〜400、400〜200、200〜10
0、100〜50、50μｍ以下及び400μｍ以下の非分級粉末
に層別分級し、それぞれの粉末を所定量計量後、温度60
0℃、加工圧50kgにて圧縮成形し、φ30×^l30の粉末成形
材を得た。これらの試料を押出比Ｒ＝6.1、温度700℃に
て温間塑性加工を実施し、φ12.1×184の丸棒状磁石を
作成した。この材料から実施例１と同様の方法で一辺8m
mの立方体試料を切り出し、その磁気特性を測定した結
果第４図に示すように400μｍ以下の各分級粉末及び400
μｍ以下の非分級粉末を用いた試料では、（B.H）_max＝
7.5〜7.8MG・Oe、Hc＝4300〜4500Oe、Br＝6100〜6300G
の高い磁気特性を示し、100μｍ以下の分級品で最高の
磁気性能を示した。しかし、400μｍをこえる粉末粒子
を使用した試料では（B.H）_max＝5.4〜5.7MG・Oeと比較
的低い値を示した。[Example 4] The average diameter of powder particles having the same composition as in Example 1 and determined by the atomization method is 600 µm or more, 600 to 400, 400 to 200, and 200 to 10
Classify into non-classified powders of 0, 100 to 50, 50 μm or less and 400 μm or less by layer, measure each powder in a predetermined amount, and then set the temperature to 60.
0 ° C., was compression molded at a processing pressure of 50 kg, to obtain a powder molding material φ30 × ^l 30. These samples were subjected to warm plastic working at an extrusion ratio of R = 6.1 and a temperature of 700 ° C. to prepare round bar magnets of φ12.1 × 184. From this material, in the same manner as in Example 1, a side length of 8 m
A cubic sample of m was cut out and its magnetic properties were measured. As shown in Fig. 4, each classified powder of 400 μm or less and 400
For samples using unclassified powder of less than μm, (BH) _max =
7.5 ~ 7.8MG ・ Oe, Hc = 4300 ~ 4500Oe, Br = 6100 ~ 6300G
Shows high magnetic properties, and shows the highest magnetic performance for classified products of 100 μm or less. However, the sample using powder particles exceeding 400 μm exhibited a relatively low value of (BH) _max = 5.4 to 5.7 MG · Oe.

さらに、前記の温間押出後の丸棒材の引張強度及び、抗
折力を測定した結果、粒径に関係なく、引張強度の平均
は25〜27kg/mm²、抗折力の平均が90kg/mm²であった。
尚、押出加工後の磁石の粒径は球状粒子が針状に変形さ
れているものの真球体に換算すれば、ほぼ成形前の粉末
粒径と同じであった。Furthermore, as a result of measuring the tensile strength and the transverse rupture strength of the round bar after the warm extrusion, regardless of the particle size, the average tensile strength is 25 to 27 kg / mm ² , and the average transverse rupture strength is 90 kg. It was / mm ² .
The particle size of the magnet after extrusion was almost the same as the particle size of the powder before molding when converted into a true sphere although the spherical particles were deformed into needles.

以上のように、本発明におけるMn-Al-C系合金の粉末粒
子の平均径は、400μｍ以下のものを特定することによ
って、温間塑性加工後の磁気特性は、従来の鋳造法によ
るものに比較して、（Ｂ・Ｈ）_maxで約20％の向上Brは
ほぼ同等であるが、Hcは約80％の大巾な向上を示した。
又、後述するように温間塑性加工における加工率が一定
のもとでは、その磁気特性は従来に比較し（Ｂ・Ｈ）
_maxで20〜80％の向上となり、加工率によっては飛躍的
な向上を示した。又、その機械的強度は従来の粉末成形
とその焼結法によるものに比較し、その磁気特性は数
倍、機械的強度も数倍の永久磁石であった。As described above, by specifying the average particle diameter of the powder particles of the Mn-Al-C alloy according to the present invention to be 400 μm or less, the magnetic properties after the warm plastic working are those obtained by the conventional casting method. In comparison, in (BH) _max , about 20% improvement in Br was almost the same, but Hc showed a significant improvement of about 80%.
Further, as will be described later, under a constant working rate in warm plastic working, its magnetic characteristics are in comparison with those of the conventional one (BH).
_{The maximum} improvement was 20 to 80%, which was a dramatic improvement depending on the processing rate. Further, the mechanical strength of the permanent magnet was several times that of conventional powder molding and that of the sintering method, and its magnetic properties were several times that of the conventional one.

〔実施例５〕 実施例１と同様の組成の合金粉末を所定量計量し、約φ
30×^l80の内容積を有するダイスに投入し、温度と圧力
を変えて油圧プレスにてφ30×^l50の粉末成形材を作成
し、その各設定条件における粉末成形材の充填率と機械
的強度を調べた。その設定条件と充填率との関係を表示
に示す。[Example 5] A predetermined amount of alloy powder having the same composition as in Example 1 was weighed to obtain about φ.
Put into a die with an internal volume of 30 x ^l 80, change the temperature and pressure to create a powder compact of φ 30 x ^l 50 with a hydraulic press, and fill the powder compact with the filling rate and mechanical properties under each setting condition. The strength was checked. The display shows the relationship between the setting conditions and the filling rate.

成形温度530℃〜600℃においては、その成形後の粉末の
充填率は93〜99.5％、600℃以上においては、ほぼ100％
の充填率であった。しかし、成形温度が530℃未満の各
条件においては、充填率が90％未満となり、粉末粒子が
変形されずに破壊しているものがあった。これらの充填
率での成形材の強度は90％未満のものでは非常にもろ
く、割れやすいため、実用的には、使用が容易でなかっ
たが、90％以上の充填率の成形材では粉末成形後の温間
塑性加工（押出、圧縮、圧延等）を実施する上での材料
の搬送、取扱い、加熱、塑性加工などに耐えるだけの強
度を保有している。すなわち、成形温度は530℃以上で
あることが望ましい。 At the molding temperature of 530 ℃ -600 ℃, the filling rate of the powder after molding is 93-99.5%, and at 600 ℃ or higher, it is almost 100%.
Was the filling rate. However, under each condition where the molding temperature was less than 530 ° C., the filling rate was less than 90%, and in some cases, the powder particles were broken without being deformed. If the filling material has a strength of less than 90% at these filling rates, it is very brittle and easily cracked, so it was not practically easy to use. It possesses the strength to withstand the material conveyance, handling, heating, plastic working, etc. in carrying out the subsequent warm plastic working (extrusion, compression, rolling, etc.). That is, the molding temperature is preferably 530 ° C or higher.

さらに、前記の各条件の内、８条件を選定し、押出比Ｒ
＝6.1、押出温度700℃にて温間押出加工を実施し、得ら
れたφ12.1×^l350の丸棒材の磁気特性と機械的強度を測
定した。Further, among the above-mentioned conditions, eight conditions are selected, and the extrusion ratio R
= 6.1, extrusion temperature was 700 ° C., warm extrusion processing was performed, and the magnetic properties and mechanical strength of the obtained φ12.1 × ^l 350 round bar material were measured.

（１） 530℃ 10kg/mm² （２） 530℃ 50kg/mm² （３） 600℃ 30kg/mm² （４） 830℃ 10kg/mm² （５） 850℃ 10kg/mm² （６） 850℃ 50kg/mm² （７） 870℃ 50kg/mm² （８） 920℃ 50kg/mm² 押出加工後に、押出方向と平行な方向の磁気特性を測定
した結果、上記の温度成形条件（１）〜（６）において
は、その磁気特性は良好で、有為差がほとんどなく、例
えば条件（１）においては、（Ｂ・Ｈ）_max＝7.7Mg・O
e、Hc＝4400Oe、Br＝6300G、条件（６）においては（Ｂ
・Ｈ）_max＝7.6MG・Oe、Hc＝4350Oe、Br＝6150Gであっ
た。又、その機械的強度においては、各条件間に有為差
がほとんどなく、引張強度の平均値は25〜27kg/mm²抗折
力の平均値は90kg/mm²であった。これらの強度値は、従
来の鋳造法によるものに比較しても、ほぼ同等で、実用
上問題はない。(1) 530 ℃ 10kg / mm ² (2) 530 ℃ 50kg / mm ² (3) 600 ℃ 30kg / mm ² (4) 830 ℃ 10kg / mm ² (5) 850 ℃ 10kg / mm ² (6) 850 ℃ 50kg / mm ² (7) 870 ° C 50kg / mm ² (8) 920 ° C 50kg / mm ² After extrusion processing, the magnetic properties in the direction parallel to the extrusion direction were measured. As a result, the above temperature molding conditions (1) to ( In 6), the magnetic properties are good, and there is almost no significant difference. For example, in condition (1), (BH) _max = 7.7MgO
e, Hc = 4400Oe, Br = 6300G, under the condition (6), (B
-H) _max = 7.6MG-Oe, Hc = 4350Oe, Br = 6150G. Further, in the mechanical strength, little significance difference between each condition, the mean value of the tensile strength is an average of 25~27kg / mm ² bending strength was 90 kg / mm ^2. These strength values are almost the same as those obtained by the conventional casting method, and there is no practical problem.

尚、成形条件（７），（８）の磁気特性は、（７）で
（Ｂ・Ｈ）_max＝3.5、（８）で（Ｂ・Ｈ）_max＝1.1MG・
Oeと大巾に減少した。これは、成形において850℃を越
える温度で、非磁性相（ｒ相，β−Mn相）への分解が促
進されるための現象と考えられる。The magnetic properties of molding conditions (7) and (8) are (B · H) _max = 3.5 in (7) and (B · H) _max = 1.1 MG · in (8).
It was greatly reduced to Oe. This is considered to be a phenomenon due to the promotion of decomposition into a non-magnetic phase (r phase, β-Mn phase) at a temperature exceeding 850 ° C during molding.

次に前記成形条件（３）で作成した成形ビレットを用
い、押出比Ｒ＝6.1、加工温度を400〜870℃の範囲内で
変化させて押出加工し、磁気特性を測定した。その結
果、530℃〜780℃の押出温度では（Ｂ・Ｈ）_maxが、7MG
・Oe以上、Hcが4000Oe以上の優れた磁石が得られた。し
かし、780℃を越える押出温度では（Ｂ・Ｈ）_maxが2MG
・Oe以下で低い磁気特性であった。これは、前述と同
様、非磁性相への分解が原因と考えられる。又、530℃
未満の押出温度では押出加工が難しく、押出加工された
場合でもクラックの発生が著しく実用に耐えるものでは
なかった。Next, using the molding billet prepared under the above-mentioned molding condition (3), extrusion was carried out while changing the extrusion ratio R = 6.1 and the processing temperature within the range of 400 to 870 ° C., and the magnetic characteristics were measured. As a result, at the extrusion temperature of 530 ℃ -780 ℃, (BH) _max is 7MG
・ An excellent magnet with Oe or more and Hc of 4000 Oe or more was obtained. However, at an extrusion temperature exceeding 780 ° C, the (BH) _max is 2MG.
・ Low magnetic properties below Oe. It is considered that this is due to the decomposition into the non-magnetic phase, as described above. Also, 530 ℃
If the extrusion temperature is lower than the above value, the extrusion process is difficult, and even if the extrusion process is performed, cracks are remarkably generated and it is not practical.

以上の結果から、本発明を効果的に実施するための圧縮
成形条件は、その圧縮成形温度が530℃〜850℃であるこ
とが、望ましく又、温間塑性加工温度は530〜780℃が望
ましいことが明らかになった。From the above results, the compression molding conditions for effectively carrying out the present invention, the compression molding temperature is preferably 530 ℃ ~ 850 ℃, it is desirable that the warm plastic working temperature is 530 ~ 780 ℃. It became clear.

〔実施例６〕 実施例５の粉末成形条件において、成形温度600℃成形
圧力30kg/mm²にてφ30×^l30の粉末成形材を作成し、そ
の後、温間押出加工の押出比Ｒを種々変えて、得られた
永久磁石の磁気特性を測定した。その結果を、第５図に
示す。第５図には従来の鋳造法による結果も並記した。In the powder molding conditions EXAMPLE 6 Example 5, to create a powder molding material molding temperature 600 ° C. molding pressure 30kg / mm ² at 0 30 × ^l 30, then, various extrusion ratio R of warm extrusion Instead, the magnetic characteristics of the obtained permanent magnet were measured. The results are shown in FIG. The results of the conventional casting method are also shown in FIG.

押出比は2.0,3.3,4.8,6.1,7.8,12.3,20.3を設定した。
尚、押出設備の制約上、押出比7.8,12.3,20.3において
は、押出比をほぼ等分し２回に分けて実施した。The extrusion ratio was set to 2.0, 3.3, 4.8, 6.1, 7.8, 12.3, 20.3.
In addition, due to the restrictions of the extrusion equipment, the extrusion ratios of 7.8, 12.3, and 20.3 were divided into two equal portions, and the extrusion ratio was divided into two equal parts.

以上の各押出比にて、得られた温間押出後の棒材の押出
方向と平行な方向の磁気特性を測定した結果、Ｒ＝2.0
の場合で（Ｂ・Ｈ）_max＝3.8MG・Oe、Hc＝2800Oe、Ｒ＝
3.3の場合で（Ｂ・Ｈ）_max＝5.6MG・Oe、Hc＝3200Oe、
Ｒ＝4.8の場で（Ｂ・Ｈ）_max＝7.3MG・Oe、Hc＝4000O
e、Ｒ＝6.1の場合で（Ｂ・Ｈ）_max＝7.7MG・Oe、Hc＝44
00Oe及びＲ＝7.8以上の各押出比においては、ほぼ同等
で（Ｂ・Ｈ）_max＝7.8〜7.9MG・Oe、Hc＝4500〜4600Oe
を示した。（Ｂ・Ｈ）_maxの値は、従来法の鋳造材によ
る磁気特性に比較して、同一の押出比では特に低い押出
比の場合（Ｒ＝２〜Ｒ＝7.8）で50％〜80％もの向上を
示し、押出比を増加させたＲ＝20.3で比較しても、20％
の向上を示した。さらに、保磁力Hcにおいては、各押出
比において70％〜80％の著しい向上を示した。At each of the above extrusion ratios, the magnetic characteristics of the obtained bar after the warm extrusion were measured in the direction parallel to the extrusion direction, and as a result, R = 2.0.
In case of (B ・ H) _max = 3.8MG ・ Oe, Hc = 2800Oe, R =
In case of 3.3, (B ・ H) _max = 5.6MG ・ Oe, Hc = 3200Oe,
When R = 4.8, (B ・ H) _max = 7.3MG ・ Oe, Hc = 4000O
In case of e and R = 6.1, (B ・ H) _max = 7.7MG ・ Oe, Hc = 44
At the extrusion ratios of 00Oe and R = 7.8 or more, they are almost the same (B · H) _max = 7.8 to 7.9 MG · Oe, Hc = 4500 to 4600 Oe.
showed that. The value of (B · H) _max is 50% to 80% at a particularly low extrusion ratio (R = 2 to R = 7.8) at the same extrusion ratio as compared with the magnetic characteristics of the conventional casting material. 20% even when compared with R = 20.3.
Showed an improvement. Furthermore, the coercive force Hc showed a remarkable improvement of 70% to 80% at each extrusion ratio.

以上のことから、本発明による永久磁石とその製造法に
よれば、従来の鋳造法による永久磁石に比較し、その温
間押出加工における加工率（押出比）が同一のもとでそ
の磁気特性は大巾に向上し一方、同一程度の磁気特性を
得るための加工率は大巾に少なくても可能となり、加工
の回数も著しく削減できる。From the above, according to the permanent magnet according to the present invention and the manufacturing method thereof, magnetic characteristics thereof are the same as those of conventional permanent magnets by the casting method under the same processing ratio (extrusion ratio) in the warm extrusion process. Is greatly improved, while the processing rate for obtaining the same magnetic characteristics can be greatly reduced, and the number of times of processing can be significantly reduced.

以上の実施例１〜６は、Mn-Al-C系合金の粉末を圧縮成
形し、得られた成形体の温間塑性加工を施す二工程を経
て、本発明の永久磁石が得られることを示したものであ
るが、この基本工法は考えることなく、１組のダイスポ
ンチを使用して所定量の粉末を直接投入し、ポンチにて
成形しつつ押出加工を行うこと、すなわち、圧縮成形と
温間押出加工を設備上で区切ることなく連続して行う一
工程の方法においても本発明と同様の効果が得られる。The above Examples 1 to 6 show that the permanent magnet of the present invention can be obtained through the two steps of compression-molding the powder of the Mn-Al-C alloy and subjecting the obtained compact to warm plastic working. As shown, without considering this basic construction method, a set of die punches is used to directly inject a prescribed amount of powder, and extrusion is performed while molding with the punches, that is, compression molding and warming. The same effect as that of the present invention can be obtained even in the one-step method in which the inter-extrusion process is continuously performed without division on the equipment.

さらに、実施例１〜６に詳述した実施例のMn-Al-C3元系
のみならず、例えば、Mn69wt％、C0.5wt％、Al30.5wt％
の３元系に対して、Ni1wt％を添加した４元系組成にお
いても実施例６の同様の実験を行った結果最高磁気特性
（Ｂ・Ｈ）_max＝7.9、Hc＝5000Oe、Br＝6300Gが得ら
れ、押出比と磁気特性の関係も前記とほぼ同様の結果が
得られた。その他、Ti,Cu,B,N,Co,Mo,Ge,Nb,Feの各元素
の１種もしくは２種以上組合わせたものにおいても同様
の結果を示し、本発明は添加元素も含むMn-Al-C系永久
磁石全般に適用できる。Furthermore, not only the Mn-Al-C ternary system of the examples detailed in Examples 1 to 6 but also, for example, Mn69wt%, C0.5wt%, Al30.5wt%
The same experiment as in Example 6 was performed on the ternary composition containing 1% by weight of Ni as compared with the ternary composition of No. 3, and the maximum magnetic characteristics (B · H) _max = 7.9, Hc = 5000Oe, Br = 6300G were obtained. The relationship between the extrusion ratio and the magnetic characteristics was almost the same as above. In addition, similar results are shown in one or a combination of two or more elements of Ti, Cu, B, N, Co, Mo, Ge, Nb and Fe. Applicable to all Al-C permanent magnets.

発明の効果 以上のように本発明によれば、従来の異方性Mn-Al-C系
磁石に比較して、（Ｂ・Ｈ）_maxは約20％向上し、特に
保磁力Hcは約80％もの大巾な向上が得られるため、磁石
形状及び、それを使用した製品のより小型化が可能とな
る。さらには、ある所定の磁気特性を得るための加工率
も大巾に減少するため、工程数の短縮、設備数の縮小
等、製造原価の低減に極めて大きな効果を生むことにな
る。As described above, according to the present invention, the (B · H) _max is improved by about 20% and the coercive force Hc is about 80 in comparison with the conventional anisotropic Mn-Al-C based magnet. %, The magnet shape and products using the magnet can be made smaller. Further, since the processing rate for obtaining a certain predetermined magnetic characteristic is greatly reduced, the manufacturing cost can be reduced significantly by reducing the number of processes and the number of facilities.

【図面の簡単な説明】[Brief description of drawings]

第１図は本発明におけるMn-Al-C系合金粉末の温間成形
材を温間押出加工した合金磁石の押出方向断面における
針状形状粒子の集合体組織の顕微鏡写真、第２図は本発
明におけるMn-Al-C系合金粉末の温間成形材の組織の電
子顕微鏡写真、第３図はMn-Al-C系合金粉末の組成値と
磁気特性の関係図、第４図はMn-Al-C系合金粉末の平均
粒径と磁石の磁気特性との関係図、第５図は本発明の粉
末成形材及び従来の鋳造材の温間押出加工における押出
比とその押出方向と平行な方向の磁気特性との関係図で
ある。FIG. 1 is a micrograph of an aggregate structure of needle-shaped particles in a cross section in the extrusion direction of an alloy magnet obtained by warm extrusion processing a warm molding material of Mn-Al-C alloy powder according to the present invention, and FIG. An electron micrograph of the structure of a warm-formed material of Mn-Al-C alloy powder according to the present invention, Fig. 3 is a relational diagram of the composition value and magnetic properties of Mn-Al-C alloy powder, and Fig. 4 is Mn- FIG. 5 shows the relationship between the average particle size of the Al-C alloy powder and the magnetic properties of the magnet. FIG. 5 shows the extrusion ratio and the extrusion direction in the warm extrusion process of the powder molding material of the present invention and the conventional casting material. It is a relationship diagram with the magnetic characteristic of a direction.

フロントページの続き (72)発明者 塚原 政晴 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 野瀬 隆 大阪府門真市大字門真1006番地 松下電器 産業株式会社内Front page continued (72) Inventor Masaharu Tsukahara 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Takashi Nose 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (4)

【特許請求の範囲】[Claims] 【請求項１】面心正方晶を主体とするマンガン−アルミ
ニウム−炭素系磁石合金からなる成形体であって、この
成形体は、その合金の塑性変形された針状形状の粒子の
集合体であって、その針状形状の長軸方向が、前記成形
体の軸方向に配列していることを特徴とする異方性マン
ガン−アルミニウム−炭素系永久磁石。1. A compact comprising a manganese-aluminum-carbon magnet alloy mainly composed of face-centered tetragonal crystals, the compact being an aggregate of plastically deformed needle-shaped particles of the alloy. An anisotropic manganese-aluminum-carbon permanent magnet, characterized in that the long axis direction of the needle shape is arranged in the axial direction of the molded body. 【請求項２】面心正方晶を主体とするマンガン−アルミ
ニウム−炭素系磁石合金からなる成形体であって、この
成形体は、その合金の塑性変形された円板形状の粒子の
集合体であって、円板形状の平面が互いに平行に配列し
ていることを特徴とする異方性マンガン−アルミニウム
−炭素系永久磁石。2. A compact comprising a manganese-aluminum-carbon magnet alloy mainly composed of face-centered tetragonal crystals, the compact being an aggregate of plastically deformed disc-shaped particles of the alloy. An anisotropic manganese-aluminum-carbon permanent magnet characterized in that the disk-shaped planes are arranged in parallel with each other. 【請求項３】マンガン−アルミニウム−炭素系合金の粉
末を、成形温度530℃〜850℃で圧縮成形し、この成形体
をさらに530℃〜780℃の温度範囲で温間塑性加工するこ
とを特徴とする異方性マンガン−アルミニウム−炭素系
永久磁石の製造法。3. A manganese-aluminum-carbon alloy powder is compression-molded at a molding temperature of 530 ° C. to 850 ° C., and the molded body is further subjected to warm plastic working in a temperature range of 530 ° C. to 780 ° C. And a method for producing an anisotropic manganese-aluminum-carbon permanent magnet. 【請求項４】粉末の粒径が平均直径400μｍ以下である
特許請求の範囲第３項記載の異方性マンガン−アルミニ
ウム−炭素系永久磁石の製造法。4. The method for producing an anisotropic manganese-aluminum-carbon permanent magnet according to claim 3, wherein the particle diameter of the powder is 400 μm or less.