JP2625708B2 - Method for producing ultra-high coercivity metal powder - Google Patents
Method for producing ultra-high coercivity metal powderInfo
- Publication number
- JP2625708B2 JP2625708B2 JP62055319A JP5531987A JP2625708B2 JP 2625708 B2 JP2625708 B2 JP 2625708B2 JP 62055319 A JP62055319 A JP 62055319A JP 5531987 A JP5531987 A JP 5531987A JP 2625708 B2 JP2625708 B2 JP 2625708B2
- Authority
- JP
- Japan
- Prior art keywords
- iron
- compound
- average
- coercive force
- powder
- 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
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
- H01F1/0573—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 obtained by reduction or by hydrogen decrepitation or embrittlement
Description
【発明の詳細な説明】 ＜産業上の利用分野＞ 本発明は磁気記録用磁性金属粉末に関するものであ
り、特にビデオ用のマスターテープや磁気カード等に使
用するのに適した超高保磁力を有する磁気記録媒体用の
磁性金属粉末に関するものである。Description: TECHNICAL FIELD The present invention relates to a magnetic metal powder for magnetic recording, and has an ultra-high coercive force particularly suitable for use in a video master tape, a magnetic card, and the like. The present invention relates to a magnetic metal powder for a magnetic recording medium.
近年、家庭用VTRの普及に伴ってビデオソフトの需要
も益々増加してきている。そこで、ビデオソフトの大量
複製が必要となっているが、これに適した方式として接
触転写方式が検討され、一部実用化されている。これ
は、原信号を記録したマスターテープと未記録のスレー
ブテープとを互いに磁性面に接触させ、磁界または熱を
加えることによりマスターテープの信号をスレーブテー
プに転写する方式である［菅谷汎、ナショナルテクニカ
ルリポート（Natl Tech Rep）20,92（1972）］。In recent years, demand for video software has been increasing with the spread of home VTRs. Therefore, mass copying of video software is required, but a contact transfer method has been studied as a method suitable for this, and some of the methods have been put to practical use. In this method, the master tape on which the original signal is recorded and the unrecorded slave tape are brought into contact with each other on a magnetic surface, and the signal of the master tape is transferred to the slave tape by applying a magnetic field or heat [Han Sugaya, National Technical Report (Natl Tech Rep) 20 , 92 (1972)].
この方式に使うマスターテープはスレーブテープ（現
在のVHS用ビデオテープの保磁力:650Oe）の2.5倍以上の
高保磁力が要求されており、この目的に沿った磁性金属
粉末として保磁力が1900Oe程度以上のものが必要とされ
ている。［今西、井上、小野、宮武、ナショナルテクニ
カルリポート25,153（1979）］。The master tape used in this system is required to have a coercive force 2.5 times or more higher than that of the slave tape (current VHS video tape: 650 Oe), and the coercive force is about 1900 Oe or more as a magnetic metal powder for this purpose. Things are needed. [Imanishi, Inoue, Ono, Miyatake, National Technical Report 25,153 (1979)].
一方、磁気カードは現在保磁力250〜360Oeのγ−Fe2O
3あるいは600〜700Oeのコバルト被着γ−Fe2O3粉末が汎
用されている。磁気カードは、その用途上日常携帯する
ので、種々の永久磁石を用いた物品（ハンドバックの口
金、事務用品、収納庫扉、冷蔵庫、テレビ、スピーカー
等々）の近傍におかれたり、あるいは触れたりして大切
な記録内容が消磁されたり滅棄されたりするトラブルが
多くなっている。そこで高保磁力を有し外部磁界に対し
て極めて消磁されにくい磁気カードが要求されている
（特公昭61−18258号）。On the other hand, the magnetic card has a γ-Fe 2 O having a coercive force of 250 to 360 Oe.
Cobalt-coated γ-Fe 2 O 3 powder of 3 or 600 to 700 Oe is widely used. Since magnetic cards are carried on a daily basis due to their use, they are placed near or touched by various permanent magnet-based articles (handbag bases, office supplies, storage doors, refrigerators, televisions, speakers, etc.). In many cases, important recorded contents are demagnetized or destroyed. Therefore, a magnetic card having a high coercive force and extremely hard to be demagnetized by an external magnetic field is required (Japanese Patent Publication No. 61-18258).
本発明は以上のように、超高保磁力を利用した磁気記
録媒体の分野に適用されるものである。As described above, the present invention is applied to the field of magnetic recording media utilizing ultra-high coercive force.
＜従来の技術＞ 保磁力1900Oe以上の金属磁性粉を製造する方法として
は、従来２種類のものがある。<Prior Art> There are two conventional methods for producing metal magnetic powder having a coercive force of 1900 Oe or more.
第１の方法は、液相還元法によるもので、Fe2+とCo2+
の金属塩水溶液を1KOeの磁界中で、水素化ホウ素ナトリ
ウム水溶液と反応させて、Fe−Co合金粉を沈殿させ、こ
れを水洗・乾燥後、約400℃の非酸化性雰囲気で熱処理
することによるものである。［ワタナベ他、アイイーイ
ーイー トランザクションズ オン マズネティクス
（IEEE Trans Magn）MAG−17,1455（1981）］。The first method is a liquid phase reduction method, in which Fe 2+ and Co 2+
By reacting the aqueous metal salt solution with an aqueous sodium borohydride solution in a magnetic field of 1 KOe to precipitate an Fe-Co alloy powder, washing and drying this, and then heat-treating it in a non-oxidizing atmosphere at about 400 ° C. Things. [Watanabe et al., IEE Transactions on Maznetics (IEEE Trans Magn) MAG-17, 1455 (1981)].
第２の方法は、不活性ガス中での蒸発法によるもの
で、タングステンフィラメントまたはボートにのせたFe
−Co合金をヘリウムもしくはアルゴンガスの数Torr〜数
百Torrの低圧雰囲気中で蒸発させるものである［タサキ
他、ジャパニーズ ジヤーナル オブ アプライド フ
ィジクス（Jpn J Appl Phys）4,707（1965）、タサキ
他、IEEE Tras Magn（前出）MAG−15,1540（1979）］。The second method is based on the evaporation method in an inert gas.
-Evaporate a Co alloy in a low pressure atmosphere of helium or argon gas of several Torr to several hundred Torr [Tasaki et al., Japanese Journal of Applied Physics (Jpn J Appl Phys) 4,707 (1965), Tasaki et al., IEEE Tras Magn (supra) MAG-15, 1540 (1979)].
＜発明が解決しようとする問題点＞ 上述の二つの方法は、性能的にはすぐれた金属粉が得
られているものの、いずれも製造コストが高価で大量生
産には向いていない。実際、現在8mmVTR用またはデジタ
ルオーディオ用の金属磁性粉の製造には上述の方法は用
いられておらず、気相還元法によるものが使用されてい
る。<Problems to be Solved by the Invention> Although the above two methods produce metal powder excellent in performance, both of them are expensive in manufacturing cost and are not suitable for mass production. In fact, at present, the above-mentioned method is not used for the production of metal magnetic powder for 8 mm VTR or digital audio, but the method using a gas phase reduction method is used.
詳しくは、第１の方法においては、約1KOeの磁界中
で、金属粉を析出させるが、このような磁界を供給でき
る空間体積は磁石の性質上あまり大きくすることができ
ない。従って、反応装置の大きさは比較的小さいものに
限定されるため、鉄粉の量産が困難である。次に、金属
粉は水溶液中で作成されるため、鉄粉表面には水分が多
量に吸着しており、放置しておくと腐食が急速に進む。
更には、鉄粉表面に水分が吸着していると、磁気塗料を
つくる際に有機系バインダー樹脂に均一に分散すること
が困難となり、ひいては、テープ性能を向上することが
できなくなる。そこで、反応後の生成鉄粉は、水分を出
来る限り除去しなければならず、これがために有機溶剤
で十分洗浄し、鉄粉表面の水分を除去する工程が必要と
なっている。Specifically, in the first method, metal powder is precipitated in a magnetic field of about 1 KOe, but the volume of space capable of supplying such a magnetic field cannot be made too large due to the properties of the magnet. Therefore, since the size of the reactor is limited to a relatively small one, mass production of iron powder is difficult. Next, since the metal powder is produced in an aqueous solution, a large amount of moisture is adsorbed on the surface of the iron powder, and corrosion proceeds rapidly if left unattended.
Furthermore, if water is adsorbed on the surface of the iron powder, it becomes difficult to uniformly disperse the powder in the organic binder resin when producing a magnetic paint, and it is impossible to improve the tape performance. Therefore, it is necessary to remove as much moisture as possible from the iron powder produced after the reaction, which requires a step of sufficiently washing with an organic solvent to remove moisture on the surface of the iron powder.
製造コスト上の次の問題点は還元剤として用いる水素
化ホウ素ナトリウムが、22,000円/Kg（PrG）と値段が高
く、更にその使用量がFeとCoの金属塩と同程度のモル数
が必要であるため、原料費が著しく高価となることであ
る。The next problem in the production cost is that sodium borohydride used as a reducing agent is expensive at 22,000 yen / Kg (PrG), and its use amount needs to be the same number of moles as Fe and Co metal salts. Therefore, the raw material cost is significantly high.
次に、第２の方法、即ち蒸発法による金属磁性粉の製
造においては、不活性ガス中で合金塊を蒸発させ、煙粒
子状にベルジャ内壁に付着させて製造する。従って、真
空蒸発装置によるバッチ式生産方式によるため、生産コ
ストが非常に高価なものとなる（10〜30万円/Kg）。こ
れは、気相還元法による鉄粉の生産コストに比較して約
１桁高い。Next, in the second method, that is, in the production of the metal magnetic powder by the evaporation method, the alloy mass is evaporated in an inert gas and attached to the inner wall of the bell jar in the form of smoke particles. Therefore, the production cost is very high (100,000 to 300,000 yen / Kg) because of the batch type production system using the vacuum evaporator. This is about one order of magnitude higher than the cost of producing iron powder by the gas phase reduction method.
以上のように、従来の方法による超高保磁力鉄粉の製
造は生産コストが非常に高価であることと、材料がFe−
Co合金（約30％Co）系の場合にしか保磁力1900Oe以上の
ものが得られない、という技術的問題点があった。As described above, the production of ultra-high coercive force iron powder by the conventional method is very expensive and the material is Fe-
There is a technical problem that a coercive force of 1900 Oe or more can be obtained only in the case of a Co alloy (about 30% Co).
＜問題を解決するための手段＞ 金属磁性粉は、生産プロセスの簡便性および製造設備
の簡易性から、その生産コストは気相還元法によるもの
が最も安価であり、従って汎用の金属磁性粉の生産に
は、この気相還元法が用いられている。即ち、あらかじ
め合成した針状のゲータイト粒子（α−FeOOH）また
は、これを脱水処理して得られる酸化鉄粒子（α−Fe2O
3）あるいはこれらにニッケル、コバルト等の他の金属
を含有させた粒子の表面に、酸化アルミニウムまたは酸
化珪素等の焼結防止剤を被着させ、これを水素気流中で
400〜500℃の温度で還元し、針状の鉄または鉄コバルト
合金粒子を得る方法である。<Means for Solving the Problem> Due to the simplicity of the production process and the simplicity of the production equipment, the production cost of the metal magnetic powder is the cheapest by the gas phase reduction method. This gas phase reduction method is used for production. That is, acicular goethite particles (α-FeOOH) synthesized in advance or iron oxide particles (α-Fe 2 O) obtained by dehydrating the particles.
3 ) Alternatively, a sintering inhibitor such as aluminum oxide or silicon oxide is applied to the surfaces of particles containing other metals such as nickel and cobalt, and the particles are coated in a hydrogen stream.
This is a method of obtaining needle-like iron or iron-cobalt alloy particles by reducing at a temperature of 400 to 500 ° C.
本発明は、この種の方法の改良法として、本出願人が
提案している方法、即ち、鉄もしくは鉄を主体とし、N
i、Coなどの他の金属を含む金属の酸化物または水和酸
化物を還元して鉄または鉄を主体とする磁性金属粉末を
製造する方法において、該酸化物または水和酸化物の表
面にAl、Cr、CeまたはNdの水溶性塩、周期律表II a族元
素の水溶性塩並びに水溶性のホウ酸化合物または過ホウ
酸化物を付着し、次いで還元性ガス中で該粉末を還元す
ることを特徴とする強磁性金属粉末の製造方法（特開昭
61−186410号）を更に鋭意検討してなしたものである。The present invention provides a method proposed by the present applicant as an improved method of this kind, namely, iron or iron-based,
i, in a method of producing a magnetic metal powder mainly composed of iron or iron by reducing an oxide or hydrated oxide of a metal containing another metal such as Co, the surface of the oxide or hydrated oxide Attach a water-soluble salt of Al, Cr, Ce or Nd, a water-soluble salt of Group IIa element of the periodic table and a water-soluble borate compound or perborate, and then reduce the powder in a reducing gas. A method for producing a ferromagnetic metal powder, comprising:
No. 61-186410).
本発明の新たな特徴点は、出発酸化物または水和酸
化物の粒子サイズを特定範囲にする、CeまたはNd化合
物の使用量を特定範囲にする、ホウ酸または過ホウ酸
化合物の使用量を特定範囲にする、の３点を行なった。
その結果、従来の方法では到底実現し得なかった保磁力
1900Oe以上の特性を有する超高保磁力金属粉末に到達す
ることに成功した。Coを含有しない鉄粉においてもこの
様な超高保磁力が実現されることは、驚くべきことと言
えよう。A new feature of the present invention is that the particle size of the starting oxide or hydrated oxide is in a specific range, the amount of Ce or Nd compound is in a specific range, the amount of boric acid or perboric acid compound is reduced. 3 points were made.
As a result, the coercive force that could not be realized by the conventional method
We have succeeded in reaching ultra-high coercive force metal powders with properties over 1900 Oe. It is surprising that such an ultra-high coercive force is realized even with iron powder containing no Co.
即ち、本発明は、鉄もしくは鉄を主体とする金属の酸
化物または水和酸化物の粒子表面に、CeまたはNdを主体
とする化合物並びにホウ酸化物もしくは過ホウ酸化物あ
るいはこれらの全ての化合物と更に周期律表II a族元素
の化合物とを付着し、次いで還元性ガス中でそれを還元
して強磁性金属粉末を製造する方法において、 前記鉄系化合物粒子の平均長軸径が0.08〜0.4μｍ、
平均短軸径0.01〜0.06μｍ、平均軸比が３〜20であり、 前記鉄系化合物に対してCeまたはNdを主体とする化合
物が１〜20wt％、ホウ素系化合物が１〜30wt％であり、
かつ、 水酸化ナトリウムで、前記粒子表面に、前記各種の化
合物を付着させることを特徴とする、 鉄もしくは鉄を主体とする金属原子の全量に対し、Ce
またはNd原子が0.1〜５原子％、Ｂ原子が１〜25原子％
であり、金属粉末粒子の平均長軸径が0.09〜0.2μｍ、
平均短軸径0.01〜0.04μｍ、平均軸比が４〜20であり、
磁気特性が保磁力1900Oe以上、飽和磁化量100emu/g以上
の超高保磁力金属粉末の製造方法である。That is, the present invention provides, on the particle surface of an oxide or hydrated oxide of iron or a metal mainly composed of iron, a compound mainly composed of Ce or Nd and a borate or perborate or all of these compounds And further attaching a compound of the Periodic Table II Group a element, and then reducing it in a reducing gas to produce a ferromagnetic metal powder, wherein the average long axis diameter of the iron-based compound particles is 0.08 to 0.4 μm,
The average minor axis diameter is 0.01 to 0.06 μm, the average axis ratio is 3 to 20, and the compound mainly composed of Ce or Nd is 1 to 20 wt% and the boron compound is 1 to 30 wt% based on the iron compound. ,
And bonding the various compounds to the surface of the particles with sodium hydroxide, wherein the total amount of iron or iron-based metal atoms is Ce
Or 0.1-5 atomic% of Nd atoms and 1-25 atomic% of B atoms
The average major axis diameter of the metal powder particles is 0.09 to 0.2 μm,
The average short axis diameter is 0.01 to 0.04 μm, the average axis ratio is 4 to 20,
This is a method for producing an ultra-high coercive force metal powder having a magnetic property of 1900 Oe or more in coercive force and a saturation magnetization of 100 emu / g or more.
次に、この様な本発明を更に具体的に詳述する。 Next, the present invention will be described more specifically.
まず、CeまたはNdの水溶性塩あるいは状況に応じてこ
れらの他にAl、Cr等の他の３価の元素の水溶性塩を任意
成分として混合し、pH＝２〜５の水溶液を調製し、これ
に長さ0.08〜0.4μｍ、幅0.01〜0.06μｍの針状の酸化
鉄またはオキシ水酸化鉄あるいはこれらにNi、Coなどの
他の金属を任意成分として含有させた粉末を分散させ
る。次いで、撹拌を行ないながら、周期律表II a族元素
の水溶性塩の水溶液を加えた後、ホウ素を主とする化合
物例えばホウ酸、ホウ酸塩またはペルオキソホウ酸塩等
のホウ酸化合物もしくは過ホウ酸化物の１種以上を含む
水溶液を添加する。次に、１規定の水酸化ナトリウム水
溶液を少しずつ加え、この懸濁液のpHを約８に合わせ
る。これにより、懸濁液は、前記鉄系化合物の粒子表面
にCe、Nd、Ｂ、II a族元素等の化合物が付着して凝集気
味となり、スラリーの濾別が容易となる。濾別したスラ
リーは、約100℃で乾燥後、水素ガス中で約400℃で加熱
還元することによって金属粉末となる。First, a water-soluble salt of Ce or Nd or, if necessary, a water-soluble salt of another trivalent element such as Al or Cr as an optional component is mixed to prepare an aqueous solution having a pH of 2 to 5. Then, a needle-like iron oxide or iron oxyhydroxide having a length of 0.08 to 0.4 [mu] m and a width of 0.01 to 0.06 [mu] m, or a powder containing these and other metals such as Ni and Co as optional components is dispersed therein. Then, while stirring, an aqueous solution of a water-soluble salt of a Group IIa element in the periodic table is added, and then a boron-based compound such as a boric acid compound such as boric acid, borate or peroxoborate or a boric acid compound is added. An aqueous solution containing one or more borate is added. Next, 1N aqueous sodium hydroxide solution is added little by little to adjust the pH of the suspension to about 8. As a result, the suspension tends to be agglomerated due to the attachment of compounds such as Ce, Nd, B, and IIa elements to the surface of the particles of the iron-based compound, and the slurry can be easily separated by filtration. The slurry separated by filtration is dried at about 100 ° C., and then reduced by heating at about 400 ° C. in hydrogen gas to be a metal powder.
本発明において用いられる鉄系化合物粒子のサイズ
は、平均長軸径が0.08〜0.4μｍ、平均短軸径が0.01〜
0.06μｍ、平均軸比が３〜20、とりわけ、各々0.1〜0.3
μｍ、0.02〜0.04μｍ、４〜20の範囲であれば良好な結
果を得る。また、これら鉄系化合物としてゲータイト中
にコバルトを添加したものを用いる場合には、得られる
金属粉末の飽和磁化量が増加するので、形状異方性因子
により保磁力が更に大きくなることはいうまでもない。The size of the iron-based compound particles used in the present invention, the average major axis diameter is 0.08 to 0.4 μm, the average minor axis diameter is 0.01 to
0.06 μm, average axis ratio of 3 to 20, especially 0.1 to 0.3 each
Good results are obtained within the range of μm, 0.02 to 0.04 μm, and 4 to 20. Further, when using a compound obtained by adding cobalt in goethite as these iron-based compounds, the saturation magnetization of the obtained metal powder increases, so that the coercive force is further increased by the shape anisotropy factor. Nor.
本発明において用いられる、CeまたはNdを主体とする
化合物あるいはこれらと併用し得る他の３価の元素の水
溶製塩としては、硝酸塩、塩酸塩、硫酸塩、酢酸塩、ギ
酸塩が推奨し得る。しかし、塩酸塩または硫酸塩をもち
いた場合には鉄粉の表面に塩素や硫黄元素が吸着され残
存するので、耐食性が幾分劣り、また、酢酸塩やギ酸塩
の場合は水溶液のpHが６付近であるため、被表面処理物
質を１次粒子まで分散させるのが多少難しい。従って、
とりわけ硝酸塩が、分散と耐食性の観点から最も好適で
ある。Nitrate, hydrochloride, sulfate, acetate, and formate can be recommended as the water-soluble salt of Ce or Nd or another trivalent element that can be used in combination with these compounds used in the present invention. However, when hydrochloride or sulfate is used, chlorine and sulfur elements are adsorbed and remain on the surface of the iron powder, so that the corrosion resistance is somewhat inferior. In the case of acetate or formate, the pH of the aqueous solution is 6%. Because it is near, it is somewhat difficult to disperse the material to be surface-treated to the primary particles. Therefore,
In particular, nitrates are most preferred from the viewpoint of dispersion and corrosion resistance.
本発明においてII a族元素としてはMg,Ca,SrおよびBa
等があげられ、またそれらの水溶性塩としてはギ酸塩、
酢酸塩、塩酸塩、硫酸塩、硝酸塩（例えばMg（HCOO）２
・2H2O,Mg（CH3COO）２・4H2O,MgCl2・6H2O,MgSO4・7H2
O,Mg（NO3）２・6H2O,Ca（CH3COO）２・H2O等）が挙げ
られる。ここで、酢酸塩または硝酸塩を用いた場合に
は、得られた金属粉末の耐食性が優れるので好適であ
る。これらII a族元素は、金属粉末の超高保磁力の発現
には直接寄与しないが、還元時において、多少の還元促
進効果をもたらすことの他に、金属磁性粉の表面に存在
して、塗料中における磁界配向性を良好にさせる作用を
有し、本発明金属粉末において重要な存在である。In the present invention, Mg, Ca, Sr and Ba
And the water-soluble salts thereof include formate,
Acetate, hydrochloride, sulfate, nitrate (eg Mg (HCOO) 2
· 2H 2 O, Mg (CH 3 COO) 2 · 4H 2 O, MgCl 2 · 6H 2 O, MgSO 4 · 7H 2
O, Mg (NO 3 ) 2 .6H 2 O, Ca (CH 3 COO) 2 .H 2 O). Here, it is preferable to use an acetate or a nitrate since the obtained metal powder has excellent corrosion resistance. These IIa group elements do not directly contribute to the development of the ultra-high coercive force of the metal powder, but, in addition to providing a slight reduction promoting effect during the reduction, exist on the surface of the metal magnetic powder and are present in the paint. And has an action of improving the magnetic field orientation in the present invention, and is important in the metal powder of the present invention.
これら各塩の使用量は、鉄系化合物に対して述べる
と、CeまたはNdあるいは両者の混合物の水溶性塩、例え
ば、硝酸第一セリウムまたは硝酸ネオジウムの使用量
は、１〜20wt％とりわけ２〜15wt％となる範囲が好まし
い。換言すると、これらの希土類イオンは全量鉄系化合
物粒子表面に付着するので、鉄もしくは鉄を主体とする
金属原子に対するCeまたはNd原子の割合は、0.1〜５原
子％なる範囲である。付着量が少ないと焼結防止効果が
不十分で、粒子形状が損なわれ、保磁力が低下する。一
方、付着量が多すぎると、鉄系化合物自身の還元が進ま
なくなり、また、粒子分解が生じやすくなり、大きな保
磁力は得られにくくなる。In terms of the amount of each of these salts, the amount of a water-soluble salt of Ce or Nd or a mixture of both, such as cerous nitrate or neodymium nitrate, is 1 to 20 wt%, especially The range which becomes 15 wt% is preferable. In other words, since all of these rare earth ions adhere to the surface of the iron-based compound particles, the ratio of Ce or Nd atoms to iron or metal atoms mainly composed of iron is in the range of 0.1 to 5 atomic%. If the amount of adhesion is small, the effect of preventing sintering is insufficient, the particle shape is impaired, and the coercive force decreases. On the other hand, if the adhesion amount is too large, the reduction of the iron-based compound itself does not proceed, and particles are easily decomposed, so that it is difficult to obtain a large coercive force.
次に、II a族元素の水溶性塩、例えば、酢酸マグネシ
ウムの使用量は鉄系化合物に対して0.1〜10wt％となる
範囲、換言すると、鉄系金属原子に対するMg原子の付着
量として0.01〜３原子％となる範囲が好ましい。付着量
がこれより多すぎると還元時の焼結が進みやすくなり、
保磁力制御がしにくくなる。Next, the amount of a water-soluble salt of a Group IIa element, for example, magnesium acetate is in the range of 0.1 to 10% by weight based on the iron-based compound, in other words, 0.01 to 10 wt. A range of 3 atomic% is preferable. If the adhesion amount is too large, sintering during reduction tends to proceed,
Coercive force control becomes difficult.
最後に、ホウ酸、ホウ酸塩またはペルオキソホウ酸塩
等のホウ素系化合物の使用量は、鉄系化合物に対して１
〜30wt％、換言すると鉄系金属原子に対するＢ原子の付
着量として、１〜25原子％となる範囲である。付着量が
これより少なすぎると粉末粒子または粒子間の焼結が生
じ、超高保磁力を出すことが出来なくなる。一方、付着
量が多すぎると還元が困難となるほかに、塗料化時の金
属粉末の分散性が悪くなる。Finally, the amount of the boron compound such as boric acid, borate or peroxoborate used is 1 to 1 per iron compound.
-30 wt%, in other words, the amount of B atoms attached to iron-based metal atoms is in the range of 1-25 atomic%. If the adhesion amount is too small, sintering of the powder particles or between the particles occurs, and it becomes impossible to produce an ultra-high coercive force. On the other hand, if the adhesion amount is too large, reduction becomes difficult, and the dispersibility of the metal powder during coating becomes poor.
上記の如く、焼結防止表面処理されたゲータイトある
いはこれを空気中で加熱脱水処理して得られた酸化鉄等
の鉄系化合物、即ち被還元物を加熱還元する温度は、30
0〜500℃の範囲が好適である。これより還元温度が低い
と還元が不十分となり、高いと粒子の焼結が生じるよう
になり、保磁力が低下する。As described above, the temperature at which the sintering-preventive surface-treated goethite or an iron-based compound such as iron oxide obtained by heating and dehydrating the same in air, that is, the temperature of the substance to be reduced by heating is 30
A range from 0 to 500 ° C is preferred. If the reduction temperature is lower than this, the reduction becomes insufficient, and if it is higher, sintering of the particles occurs, and the coercive force decreases.
還元後の鉄粉はトルエン等の有機溶媒に浸漬して、空
気を吹き込み徐酸化後空気中に取り出すか、もしくは酸
素ガスを混入した窒素ガスを通気し、酸素ガス濃度を少
しずつ高めながら徐酸化を行ない、空気中に取り出して
も良い。The reduced iron powder is immersed in an organic solvent such as toluene and then blown into the air and slowly oxidized, or taken out into the air, or gradually gasified with oxygen gas mixed with nitrogen gas while gradually increasing the oxygen gas concentration. And take it out into the air.
この様にして得られた金属粉末は、Ni、Coなどの鉄以
外の金属を任意成分として含有することのある、鉄を主
体とする金属粉末であって、鉄もしくは鉄を主体とする
金属原子の全量に対し、CeまたはNd原子が0.1〜５原子
％、Ｂ原子が１〜25原子％を含有している。しかもこれ
は、場合により必要とされたときは、更にMg、Ca、Sr、
Ba等のII a族元素の少なくとも１種を併せて包含してい
る。そしてこの金属粉末は、その粉末粒子の平均長軸径
が0.06〜0.5μｍ、平均短軸系が0.01〜0.04μｍ、平均
軸比が４〜20であり、保磁力1900Oe以上、飽和磁化量10
0emu/g以上という超高保磁力の磁気特性を有するもので
ある。The metal powder thus obtained is an iron-based metal powder which may contain a metal other than iron such as Ni or Co as an optional component, and is iron or a metal atom mainly containing iron. Contains 0.1 to 5 atomic% of Ce or Nd atoms and 1 to 25 atomic% of B atoms with respect to the total amount of In addition, this may further include Mg, Ca, Sr,
At least one element of Group IIa such as Ba is also included. This metal powder has an average major axis diameter of 0.06 to 0.5 μm, an average minor axis system of 0.01 to 0.04 μm, an average axis ratio of 4 to 20, a coercive force of 1900 Oe or more, and a saturation magnetization of 10
It has magnetic properties of an ultra-high coercive force of 0 emu / g or more.
本発明のこの超高保磁力金属粉末は、常法に従って、
例えばポリウレタン樹脂や塩ビ−酢ビ共重合体等のバイ
ンダー成分中に、要すれば各種溶剤の存在下に、分散す
ることにより塗料化することができる。更にその塗料
を、常法により、例えばポリエチレンテレフタレートフ
ィルムの如き非磁性支持体上に塗膜化することにより、
超高保磁力の磁性層を有する磁気記録媒体が得られる。
そしてこの様な磁気記録媒体は、保磁力1900Oe以上、飽
和磁束密度2500Gauss以上の磁気特性を有する。This ultra-high coercivity metal powder of the present invention, according to a conventional method,
For example, a coating can be obtained by dispersing in a binder component such as a polyurethane resin or a polyvinyl chloride-vinyl acetate copolymer, if necessary, in the presence of various solvents. Further, by coating the paint on a non-magnetic support such as a polyethylene terephthalate film by a conventional method,
A magnetic recording medium having a magnetic layer with an ultra-high coercive force is obtained.
Such a magnetic recording medium has magnetic properties of a coercive force of 1900 Oe or more and a saturation magnetic flux density of 2500 Gauss or more.
＜発明の効果＞ 以上の如く、本発明の超高保磁力金属粉末は、その製
造法が汎用の金属磁性粉製造法即ち気相還元法で製造で
きるという、工業的メリットをもち、かつ材料的には必
ずしもコバルトを用いなくても鉄のみでも済むというメ
リットをもつ。性能的には、保磁力1900Oe以上のすぐれ
た磁気特性を示すだけでなく、塗料分散性にすぐれてい
るので種々の超高保磁力磁気記録媒体の製造が可能であ
り、非磁性支持体上にバインダー成分と共に磁性層を形
成すると、保磁力1900Oe以上、飽和磁束密度2500Gauss
以上の超高保磁力磁気記録媒体が得られる。従って、高
性能マスターテープが極めて安価に提供できる。<Effects of the Invention> As described above, the ultra-high coercive force metal powder of the present invention has an industrial merit that its production method can be produced by a general-purpose metal magnetic powder production method, that is, a gas phase reduction method, and it has a material advantage. Has the advantage that it is not necessary to use cobalt but only iron. In terms of performance, in addition to exhibiting excellent magnetic properties with a coercive force of 1900 Oe or more, it has excellent paint dispersibility, so it is possible to manufacture various ultra-high coercive force magnetic recording media, and a binder on a non-magnetic support When the magnetic layer is formed together with the components, the coercive force is 1900 Oe or more and the saturation magnetic flux density is 2500 Gauss.
The above-described magnetic recording medium having a very high coercive force can be obtained. Therefore, a high-performance master tape can be provided at extremely low cost.
以下に実施例および比較例を挙げ、本発明の内容を更
に具体的に説明する。（尚、％は特に記載がない限り、
重量基準を意味する。） 実施例１ 平均の長さ0.2μｍ、幅0.03μｍ、針状比約７のゲー
タイト（α−FeOOH）粒子の粉末30gをとり、これをｘ％
の硝酸ネオジウム［Nd（NO3）３・H2O］を溶かした硝酸
ネオジウム水溶液300ml（硝酸ネオジウム30/100xg含
有）に浸漬し、撹拌機と超音波分散機をもちいて分散さ
せた。次いで、酢酸マグネシウム［Mg（CH3COO）２・4H
2O］がゲータイトに対してｙ％となるようにした酢酸マ
グネシウム水溶液20ml（酢酸マグネシウム30/100yg含
有）を加えて該粉末スラリーを撹拌した後、ホウ酸をゲ
ータイトに対してｚ％となるようにしたホウ酸水溶液13
0ml（ホウ酸30/100zg含有）を加えて該粉末スラリーを
再び撹拌分散させた。その後、この懸濁液に1Nのカセイ
ソーダ水溶液を滴下してpHを８とした後、濾別して固形
分約30％のウエットケーキとし、次いで、このウエット
ケーキを空気中で約100℃で乾燥した。Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. (Note that unless otherwise stated,
Means by weight. Example 1 30 g of powder of goethite (α-FeOOH) particles having an average length of 0.2 μm, a width of 0.03 μm and an acicular ratio of about 7 was taken, and this was x%
Of neodymium nitrate [Nd (NO 3 ) 3 .H 2 O] was immersed in 300 ml of an aqueous neodymium nitrate solution (containing 30/100 × g neodymium nitrate) and dispersed using a stirrer and an ultrasonic disperser. Then, magnesium acetate [Mg (CH 3 COO) 2 · 4H
After adding 20 ml of an aqueous solution of magnesium acetate (containing 30/100 yg of magnesium acetate) so that 2 O] becomes y% with respect to goethite, and stirring the powder slurry, boric acid is adjusted to z% with respect to goethite. Boric acid aqueous solution 13
0 ml (containing 30/100 zg of boric acid) was added, and the powder slurry was again stirred and dispersed. Thereafter, a 1N aqueous solution of sodium hydroxide was added dropwise to the suspension to adjust the pH to 8, followed by filtration to obtain a wet cake having a solid content of about 30%. Then, the wet cake was dried at about 100 ° C. in air.
次に、この乾燥ケーキを粉砕した後、20gを取り、固
定床式管状還元炉に入れ、窒素ガスで空気を置換した
後、温度を上昇し420℃とした。次いで、窒素ガスを止
めて水素ガスを4l/minの流量で流通させ、６時間還元を
行なって金属鉄粉末とした。これを、室温に下げ、再び
窒素ガスで置換後、トルエン中に、20時間浸漬した。そ
の後、この金属鉄粉を空気中で濾別乾燥を行なって安定
化した鉄粉を得た。Next, after the dried cake was pulverized, 20 g of the dried cake was placed in a fixed-bed tubular reduction furnace, the air was replaced with nitrogen gas, and the temperature was raised to 420 ° C. Next, the nitrogen gas was stopped and hydrogen gas was passed at a flow rate of 4 l / min, and reduction was performed for 6 hours to obtain metallic iron powder. This was cooled to room temperature, replaced with nitrogen gas again, and immersed in toluene for 20 hours. Then, the metal iron powder was filtered and dried in the air to obtain a stabilized iron powder.
このようにして得た鉄粉の磁気特性をゲータイトに対
する焼結防止表面処理剤の濃度（x,y,z）に対して示す
と表１のようになる。ここで、磁気特性は東英工業社製
振動試料型磁力計を用いて最大測定磁界10KOeにて行な
った。尚、測定サンプルの充填率は約1.2g/cm3で行なっ
た。表にみるように、硝酸ネオジウム5wt％ゲータイト
付近で保磁力が最大となり、2150Oeに達する。ホウ酸は
添加量を増加していくと保磁力が単調に増大するように
なる。他方、酢酸マグネシウムは小量の添加では保磁力
にほとんど変化がみられないが、5wt％を越えるように
なると還元が進み飽和磁化量が少し大きくなり、保磁力
が減少するようになる。ホウ酸一定量のところで硝酸ネ
オジウムを増加すると保磁力が減少するが、ホウ酸量を
増すとこの傾向が抑えられることがわかる。Table 1 shows the magnetic properties of the iron powder thus obtained with respect to the concentration (x, y, z) of the sintering preventing surface treatment agent for goethite. Here, the magnetic characteristics were measured using a vibration sample type magnetometer manufactured by Toei Kogyo Co., Ltd. at a maximum measurement magnetic field of 10 KOe. The filling rate of the measurement sample was about 1.2 g / cm 3 . As shown in the table, the coercive force becomes maximum near neodymium nitrate 5 wt% goethite, reaching 2150 Oe. As the amount of boric acid increases, the coercive force monotonously increases. On the other hand, the addition of a small amount of magnesium acetate hardly changes the coercive force, but when it exceeds 5% by weight, reduction proceeds and the saturation magnetization slightly increases, and the coercive force decreases. It can be seen that the coercive force decreases when neodymium nitrate is increased at a fixed amount of boric acid, but this tendency is suppressed when the amount of boric acid is increased.
実施例２ 実施例１において、硝酸ネオジウムの代わりに、硝酸
セリウムを用いた以外は実施例１と同様にして鉄粉を製
造した。得られた鉄粉の磁気特性を表２に示すが、ホウ
酸添加量もしくは硝酸セリウムの添加量の変化に対し
て、実施例１の硝酸ネオジウムの場合と同様の保磁力の
大きさと変化を示すことがわかる。Example 2 An iron powder was produced in the same manner as in Example 1 except that cerium nitrate was used instead of neodymium nitrate. The magnetic properties of the obtained iron powder are shown in Table 2, and show the same magnitude and change in coercive force as in the case of neodymium nitrate of Example 1 with respect to changes in the amount of boric acid or the amount of cerium nitrate added. You can see that.
実施例３ 実施例１と同様の操作方法で、NdまたはCeの水溶性
塩、周期律表II a族元素の水溶性塩、水溶性のホウ酸化
合物の種類と濃度を代えて種々の鉄粉を製造し、その磁
気特性を測定した。その結果をまとめて表３に示すが、
実施例１とほぼ同様の磁気特性を示しているのがわか
る。Example 3 Various iron powders were prepared in the same manner as in Example 1 except that the water-soluble salt of Nd or Ce, the water-soluble salt of Group IIa element of the Periodic Table II, and the water-soluble boric acid compound were changed. Was manufactured and its magnetic properties were measured. Table 3 summarizes the results.
It can be seen that the magnetic characteristics are almost the same as those of the first embodiment.
実施例４ 実施例２において、硝酸セリウムの一部を他の３価の
元素の水溶性塩の１例としての硝酸アルミニウムで置換
し、かつ、ホウ酸添加量を20wt％/FeOOHとした以外は、
実施例２と同様にして鉄粉を製造した。得られた鉄粉の
磁気特性を表４に示すが、Ce添加量の増加とともに保磁
力が増大していくのがわかる。Example 4 In Example 2, except that a part of cerium nitrate was replaced with aluminum nitrate as an example of a water-soluble salt of another trivalent element, and the amount of boric acid added was 20 wt% / FeOOH. ,
Iron powder was produced in the same manner as in Example 2. The magnetic properties of the obtained iron powder are shown in Table 4, and it can be seen that the coercive force increases as the Ce content increases.
比較例１ 実施例１において、酢酸マグネシウムおよびホウ酸を
用いず、酢酸ネオジウムのみをゲータイト表面処理剤と
して用いて、実施例１と同様な方法で鉄粉を製造した。
得られた鉄粉の磁気特性を表５に示すが、保磁力が1000
Oe以下に小さくなっている。電子顕微鏡観察の結果、鉄
粉粒子の焼結が大きく、針状性が非常に悪くなってい
た。Comparative Example 1 In Example 1, an iron powder was produced in the same manner as in Example 1, except that only neodymium acetate was used as the goethite surface treatment agent without using magnesium acetate and boric acid.
Table 5 shows the magnetic properties of the obtained iron powder.
It is smaller than Oe. As a result of observation with an electron microscope, the sintering of the iron powder particles was large, and the acicularity was extremely poor.
比較例２ 比較例１において、硝酸ネオジウムの代わりに、硝酸
セリウムを用いた場合であるが、比較例１と同様の結果
となっている。Comparative Example 2 In Comparative Example 1, a case was shown in which cerium nitrate was used instead of neodymium nitrate.
比較例３ 実施例１において、ゲータイトの焼結防止表面処理剤
として、ホウ酸のみを用いた場合であるが、保磁力が15
00〜1600Oeと比較的大きく、ホウ酸の焼結防止処理剤と
しての効果が大きいことを示している。Comparative Example 3 In Example 1, a case where only boric acid was used as a surface treatment agent for preventing sintering of goethite was used.
It is relatively large, from 00 to 1600 Oe, indicating that boric acid has a great effect as a sintering preventing agent.
比較例４ 実施例１において、ゲータイトの焼結防止表面処理剤
として硝酸マグネシウムとホウ酸を用いた場合である。
比較例３のホウ酸のみの場合より、保磁力が若干大きく
なる程度となっている。Comparative Example 4 In Example 1, a case where magnesium nitrate and boric acid were used as a surface treatment agent for preventing sintering of goethite was used.
The coercive force is slightly larger than the case of boric acid alone of Comparative Example 3.
比較例５ 実施例１において、硝酸ネオジウムの代わりに硝酸ア
ルミニウムを用いた以外は実施例１と同様な方法で鉄粉
を製造した。得られた鉄粉の磁気特性は表５にみるよう
に、保磁力が1800Oe付近の大きな値を示すが、硝酸ネオ
ジウムあるいは硝酸セリウムを用いた場合のように、19
00Oeを越すに至らない。Comparative Example 5 Iron powder was produced in the same manner as in Example 1, except that aluminum nitrate was used instead of neodymium nitrate. As shown in Table 5, the magnetic properties of the obtained iron powder show a large coercive force in the vicinity of 1800 Oe. However, as shown in Table 5, as in the case of using neodymium nitrate or cerium nitrate,
Not to exceed 00Oe.
比較例６ 実施例１において、硝酸ネオジウムの代わりに硝酸ク
ロムを用いた以外は実施例１と同様な方法で鉄粉を製造
した場合であるが、比較例５の硝酸アルミニウムを用い
た場合と同程度の保磁力を示している。Comparative Example 6 An iron powder was produced in the same manner as in Example 1 except that chromium nitrate was used instead of neodymium nitrate. It shows a degree of coercivity.
実施例５ 実施例１において、用いるゲータイト粒子のサイズを
長さ0.06μｍから0.3μｍまで種々に変化させ、また、
焼結防止表面処理剤として、硝酸ネオジウム5wt％、酢
酸マグネシウム3wt％、ホウ酸20wt％を用いた以外は実
施例１と同様な方法で種々の粒子サイズの鉄粉を製造し
た。得られた鉄粉の平均粒子径、軸比、比表面積および
磁気特性を表６に示す。表にみるように、鉄粉の長軸径
が0.06μｍ、軸比４付近からHcが急激に増加し、長軸径
が0.09μｍになると、Hcが2000Oeを越えるようになる。
長軸径0.13〜0.15μｍ付近でHcは極大をとった後、粒子
径の増大とともに減少の傾向を示す。Hcが極大を示す粒
子径は、短軸径が200Åであることから、単磁区粒子の
臨界寸法となっていると考えられる。［ルボルスキー
（F.E.Luborsky）他、ジヤーナル オブ アプライド
フィジクス（J Appl Phys）31 68S（1960）］ここで、
注目すべきは、鉄粉のBET法で求めた比表面積が粒子サ
イズが小さいにもかかわらず低い値を示すことである。
これは次の比較例７で示す方法で製造した鉄粉のBET値
と比較すると明瞭である。電子顕微鏡観察の結果による
と、これら鉄粒子では、粒子内部の空孔が少なく粒子表
面もなめらかとなっている。Example 5 In Example 1, the size of the goethite particles used was varied from 0.06 μm to 0.3 μm in length, and
Iron powders of various particle sizes were produced in the same manner as in Example 1 except that 5 wt% of neodymium nitrate, 3 wt% of magnesium acetate, and 20 wt% of boric acid were used as surface treatment agents for preventing sintering. Table 6 shows the average particle size, axial ratio, specific surface area, and magnetic properties of the obtained iron powder. As shown in the table, when the major axis diameter of the iron powder is 0.06 μm and the axial ratio is around 4, Hc sharply increases. When the major axis diameter becomes 0.09 μm, Hc exceeds 2000 Oe.
Hc reaches a maximum around 0.13 to 0.15 μm in the major axis diameter, and then decreases as the particle diameter increases. The particle diameter at which Hc has a maximum is considered to be the critical dimension of the single magnetic domain particle because the minor axis diameter is 200 °. [FELuborsky, etc., Journal of Applied
Physics (J Appl Phys) 31 68S (1960)]
It should be noted that the specific surface area of the iron powder determined by the BET method is low even though the particle size is small.
This is clear when compared with the BET value of the iron powder produced by the method shown in Comparative Example 7 below. According to the results of electron microscopic observation, these iron particles have few pores inside the particles and the particle surface is smooth.
比較例７ 実施例５において、ゲータイト粒子の焼結防止表面処
理剤として硝酸アルミニウム5wt％、酢酸マグネシウム3
wt％、ホウ酸5wt％を用いた以外は実施例４と同様な方
法で、種々の粒子サイズの鉄粉を製造した。得られた鉄
粉の平均粒子径、軸比、比表面積および磁気特性を表６
に示す。実施例５との比較で明らかなように、同一粒子
サイズでも比表面積は10〜5m2/g大きく、保磁力は最大1
600Oeと小さい。Comparative Example 7 In Example 5, aluminum nitrate 5 wt% and magnesium acetate 3 were used as surface treatment agents for preventing sintering of goethite particles.
Iron powders of various particle sizes were produced in the same manner as in Example 4, except that wt% and 5 wt% of boric acid were used. Table 6 shows the average particle size, axial ratio, specific surface area and magnetic properties of the obtained iron powder.
Shown in As is clear from the comparison with Example 5, the specific surface area is large by 10 to 5 m 2 / g and the coercive force is 1 max at the same particle size.
As small as 600 Oe.
実施例６ 実施例５で製造した鉄粉のうち、鉄粒子の長軸径0.1
μｍ、0.13μｍ、および0.2μｍのものについて、以下
の処方で磁性塗料を製造した。即ち、鉄粉9gをとり、ポ
リウレタン樹脂（Pandex−Ｂ、大日本インキ化学社商品
名）1.5g、塩ビ・酢ビ共重合体（Ｕ−528、ユニオンカ
ーバイド社商品名）1.5g、メチルイソブチルケトンとト
ルエンの1:1混合液39gおよびレシチン0.27gおよびガラ
スビーズ40gとを混合して東洋精機製ペイントシエーカ
ーで４時間分散して磁性塗料を製造した。この塗料を50
μｍ間隙のアプリケーターを用いてポリエステルフィル
ムに塗布し、約4KOeの対極配向型磁石の中を通過させた
後、室温にて乾燥した。次いで、温度80℃、線圧100Kg/
cmでカレンダリング処理を行なって磁性塗膜を得た。得
られた塗膜のカレンダー前（後）の光沢およびカレンダ
ー後の磁気特性を表７に示す。ここで、光沢は村上色彩
技術研究所製GMX−200型（入射角60゜）を用いて測定し
た。磁気特性は鉄粉の場合と同様にVSM磁力計を用いて
最大印加磁界10KOeにて測定した。表にみるように、本
方法にて得た超高保磁力鉄粉は塗料分散性と充填性が良
く、高い光沢値と飽和磁束密度Bsおよび角型比を示す。
また、保磁力の値も鉄粉のときよりもわずか低下するの
みであり、十分高い値を保つことがわかる。Example 6 Of the iron powder produced in Example 5, the major axis diameter of the iron particles was 0.1.
For μm, 0.13 μm, and 0.2 μm, magnetic paints were produced according to the following formulation. That is, 9 g of iron powder was taken, 1.5 g of a polyurethane resin (Pandex-B, trade name of Dainippon Ink and Chemicals, Inc.), 1.5 g of a vinyl chloride / vinyl acetate copolymer (U-528, trade name of Union Carbide Co.), and methyl isobutyl ketone The mixture was mixed with 39 g of a 1: 1 mixture of toluene, 0.27 g of lecithin and 40 g of glass beads, and dispersed in a paint shaker manufactured by Toyo Seiki Co., Ltd. for 4 hours to produce a magnetic paint. 50 of this paint
It was applied to a polyester film using an applicator having a gap of μm, passed through a counter-oriented magnet of about 4 KOe, and dried at room temperature. Next, at a temperature of 80 ° C and a linear pressure of 100 kg /
A magnetic coating was obtained by performing a calendering treatment in cm. Table 7 shows the gloss before (after) the calender and the magnetic properties after the calender of the obtained coating film. Here, the gloss was measured using a GMX-200 manufactured by Murakami Color Research Laboratory (incident angle: 60 °). The magnetic properties were measured using a VSM magnetometer at a maximum applied magnetic field of 10 KOe as in the case of iron powder. As shown in the table, the ultra-high coercive force iron powder obtained by the present method has good paint dispersibility and filling properties, and exhibits high gloss value, saturation magnetic flux density Bs and squareness.
In addition, the value of the coercive force is only slightly decreased as compared with the case of the iron powder, and it can be seen that the value is kept sufficiently high.
比較例８ 実施例５において、用いた鉄粉を市販の8mmVTR用鉄粉
に変えた以外は実施例５と同様にして磁性塗膜を作製し
た。この結果を同じく表７に示すが、粒子サイズが大き
いにもかかわらずBET値が大きく光沢および磁気特性も
実施例６に及ばないことがわかる。Comparative Example 8 A magnetic coating film was produced in the same manner as in Example 5, except that the iron powder used was changed to a commercially available iron powder for 8 mm VTR. The results are also shown in Table 7, which shows that the BET value is large despite the large particle size, and the gloss and magnetic properties are not as good as those of Example 6.
Claims (1)
たは水和酸化物の粒子表面に、CeまたはNdを主体とする
化合物並びにホウ酸化物もしくは過ホウ酸化物あるいは
これらの全ての化合物と更に周期律表II a族元素の化合
物とを付着し、次いで還元性ガス中でそれを還元して強
磁性金属粉末を製造する方法において、 前記鉄系化合物粒子の平均長軸径が0.08〜0.4μｍ、平
均短軸径0.01〜0.06μｍ、平均軸比が３〜20であり、 前記鉄系化合物に対してCeまたはNdを主体とする化合物
が１〜20wt％、ホウ素系化合物が１〜30wt％であり、か
つ、 水酸化ナトリウムで、前記粒子表面に、前記各種の化合
物を付着させることを特徴とする、 鉄もしくは鉄を主体とする金属原子の全量に対し、Ceま
たはNd原子が0.1〜５原子％、Ｂ原子が１〜25原子％で
あり、金属粉末粒子の平均長軸径が0.09〜0.2μｍ、平
均短軸径0.01〜0.04μｍ、平均軸比が４〜20であり、磁
気特性が保磁力1900Oe以上、飽和磁化量100emu/g以上の
超高保磁力金属粉末の製造方法。1. A compound mainly composed of Ce or Nd and a borate or a perborate or all of these compounds are coated on the particle surface of an oxide or hydrated oxide of iron or a metal mainly composed of iron. Furthermore, in a method of producing a ferromagnetic metal powder by attaching a compound of Group IIa element of Periodic Table II and then reducing it in a reducing gas, the average long axis diameter of the iron-based compound particles is 0.08 to 0.4. μm, average short axis diameter 0.01 to 0.06 μm, average axis ratio is 3 to 20, 1 to 20 wt% of a compound mainly composed of Ce or Nd, 1 to 30 wt% of a boron compound based on the iron compound. And bonding the various compounds to the surface of the particles with sodium hydroxide, wherein Ce or Nd atom is 0.1 to 5 with respect to the total amount of iron or iron-based metal atoms. Atomic%, B atom is 1-25 atomic%, metal powder Ultra high coercive force with average major axis diameter of 0.09-0.2 μm, average minor axis diameter of 0.01-0.04 μm, average axis ratio of 4-20, magnetic properties of 1900 Oe or more, and saturation magnetization of 100 emu / g or more. Production method of metal powder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62055319A JP2625708B2 (en) | 1987-03-12 | 1987-03-12 | Method for producing ultra-high coercivity metal powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62055319A JP2625708B2 (en) | 1987-03-12 | 1987-03-12 | Method for producing ultra-high coercivity metal powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63222404A JPS63222404A (en) | 1988-09-16 |
| JP2625708B2 true JP2625708B2 (en) | 1997-07-02 |
Family
ID=12995228
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62055319A Expired - Lifetime JP2625708B2 (en) | 1987-03-12 | 1987-03-12 | Method for producing ultra-high coercivity metal powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2625708B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3194577B2 (en) * | 1989-12-04 | 2001-07-30 | 戸田工業株式会社 | Method for producing needle-like magnetic metal particles containing iron as a main component |
| US5671107A (en) * | 1989-12-13 | 1997-09-23 | Hitachi, Ltd. | Large capacity magnetic disc apparatus with a particular relationship between pole thickness, saturated flux density, and recording wavelength |
| JP2700706B2 (en) * | 1990-04-20 | 1998-01-21 | 富士写真フイルム株式会社 | Magnetic recording medium and method of manufacturing the same |
| US5645652A (en) * | 1994-12-13 | 1997-07-08 | Toda Kogyo Corporation | Spindle-shaped magnetic iron-based alloy particles containing cobalt and iron as the main ingredients and process for producing the same |
| US5989516A (en) * | 1994-12-13 | 1999-11-23 | Toda Kogyo Corporation | Spindle-shaped geothite particles |
| CN113571280B (en) * | 2021-07-23 | 2024-02-13 | 包头天和磁材科技股份有限公司 | Neodymium-iron-boron magnet coarse powder auxiliary agent, preparation method and application thereof, and preparation method of magnet |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61186410A (en) * | 1985-02-13 | 1986-08-20 | Dainippon Ink & Chem Inc | Production of ferromagnetic metallic powder |
-
1987
- 1987-03-12 JP JP62055319A patent/JP2625708B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63222404A (en) | 1988-09-16 |
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