JPS61266313A - Discoid ferromagnetic powder and its production - Google Patents
Discoid ferromagnetic powder and its productionInfo
- Publication number
- JPS61266313A JPS61266313A JP60106826A JP10682685A JPS61266313A JP S61266313 A JPS61266313 A JP S61266313A JP 60106826 A JP60106826 A JP 60106826A JP 10682685 A JP10682685 A JP 10682685A JP S61266313 A JPS61266313 A JP S61266313A
- Authority
- JP
- Japan
- Prior art keywords
- disc
- cobalt
- discoid
- shaped
- plate
- 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.)
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Links
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、保磁力分布が良好であり、磁気特性に優れた
コバルト含有盤状酸化鉄強磁性粉末およびその製法に関
するものである０本発明のコバルト含有盤状酸化鉄強磁
性粉末を用いて磁気テープを作成した場合、盤状形状ゆ
えに粉末の分散性、充填性およびテープの表面平滑性に
優れた磁気記録媒体を提供することが可能である。Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a cobalt-containing disk-shaped iron oxide ferromagnetic powder having a good coercive force distribution and excellent magnetic properties, and a method for producing the same. When a magnetic tape is made using cobalt-containing disc-shaped iron oxide ferromagnetic powder, it is possible to provide a magnetic recording medium with excellent powder dispersibility, filling properties, and tape surface smoothness due to the disc-shaped shape. be.
磁気記録媒体用コバルト含有酸化鉄強磁性粉末の製造法
はこれまで種々のものが提案されておりそのなかでも有
用な方法の一つとして、針状のγ−Ｆｅ２Ｏ．粒子をコ
バルト塩と第一鉄塩とを含有する溶液に分散させた後、
これにアルカリ溶液を加え、針状のγ−ＦｅｚＯ＝粒子
上にコバルトを主体的に含む層を形成させこれを３００
〜６００℃で加熱処理してコバルト含有盤状強磁性粉末
を得る方法がある。Various methods have been proposed for producing cobalt-containing iron oxide ferromagnetic powder for magnetic recording media, and one of the most useful methods is to produce acicular γ-Fe2O. After dispersing the particles in a solution containing a cobalt salt and a ferrous salt,
Add an alkaline solution to this to form a layer containing mainly cobalt on the acicular γ-FezO=particles.
There is a method of obtaining cobalt-containing disk-shaped ferromagnetic powder by heat treatment at ~600°C.
ところがこの方法で使用されるｒ −Ｆｅ２０．粉末は
針状あるいは米粒状を有しており、針状あるいは粒状と
は本質的に形状が異なる盤状を有し、かつ１μｍ以下の
粒形のｒ−Ｆｅ２Ｏ．を用いてコバルト含有盤状強磁性
粉末を調製した例はない。However, r -Fe20. used in this method. The powder has an acicular or grain-like shape, and has a disc-like shape that is essentially different from an acicular or granular shape, and contains r-Fe2O. There is no example of preparing a cobalt-containing disc-shaped ferromagnetic powder using this method.
磁気記録媒体に用いられる始性粉末は一般に針状を有し
ており、テープに塗布した際、その針状性ゆえに凝集し
易く、分散性、充填性ならびに表面平滑性の面で問題が
生じ易い。これに替えて１μ−以下の微小な盤状のコバ
ルト含有酸化鉄磁性粉末を用いれば、盤状ゆえに粉末の
分散性、充填性ならびにテープの表面平滑性にすぐれた
磁気記録媒体を得ることが期待される。The starting powder used in magnetic recording media generally has an acicular shape, and when applied to a tape, its acicular nature tends to cause agglomeration, which tends to cause problems in terms of dispersibility, filling properties, and surface smoothness. . If we use a cobalt-containing iron oxide magnetic powder in the form of a plate of 1μ or less instead of this, it is expected that a magnetic recording medium with excellent powder dispersibility, filling properties, and tape surface smoothness due to its plate shape can be obtained. be done.
本発明の目的は盤状強磁性粉末およびその製造法を提供
することにある。An object of the present invention is to provide a disc-shaped ferromagnetic powder and a method for producing the same.
本発明者らはα−ＦｅＯＯ）ｌの粒子形態、粒度分布、
分散性等の改良について研究を続けた結果、オキシアル
キルアミンの存在下で第二鉄塩とアルカリとを水性媒体
中で反応させて水酸化第二鉄を生成させ、この水酸化第
二鉄を水熱処理すると意外にも、従来とは全く異なった
粒子形態の粒度のよ（揃った盤状詳しくは六角盤状ない
しそれに近似した形状のα−Ｆｅ００Ｈが生成し、これ
を洗浄、濾過、乾燥し、この生成α−Ｆｅ００Ｈを加熱
還元さらに酸化して盤状のγ−Ｆｅ２Ｏ．とした後、こ
の盤状γ−Ｆｅ２Ｏ゜強磁性粉末をコバルト塩またはコ
バルト塩および第一鉄塩あるいはアルカリの一方を含む
溶液に分散させ、さらに分散液に他方を加えて盤状α−
Ｆｅ、Ｏ，粒子の表面にコバルトを主体的に含む表面層
を形成させた後３００〜６００℃で加熱処理を施すと、
粒度分布が均一で粒子内にコバルトを主体的に含有する
コバルト含有盤状酸化鉄強磁性粉末が得られることを見
出しこの発明に到った。The present inventors have determined the particle morphology, particle size distribution,
As a result of continuing research on improving dispersibility, etc., we produced ferric hydroxide by reacting a ferric salt with an alkali in the presence of an oxyalkylamine in an aqueous medium. Surprisingly, the hydrothermal treatment produces α-Fe00H with a particle size that is completely different from the conventional one (a uniform disk shape, more specifically a hexagonal disk shape, or a shape similar to it), which is washed, filtered, and dried. The generated α-Fe00H is thermally reduced and further oxidized to form a disc-shaped γ-Fe2O.Then, this disc-shaped γ-Fe2O° ferromagnetic powder is treated with a cobalt salt, a cobalt salt and a ferrous salt, or an alkali. Disperse in a solution containing α-
After forming a surface layer mainly containing cobalt on the surface of Fe, O, and particles, heat treatment is performed at 300 to 600 °C,
The inventors have discovered that a cobalt-containing disc-shaped iron oxide ferromagnetic powder having a uniform particle size distribution and containing cobalt primarily within the particles can be obtained, leading to the present invention.
本発明は、粒子形態が盤状で、粒子径（盤径）が０．０
３〜１μｍ、盤状比（粒子径／厚み）が３〜１０の範囲
にある盤状酸化鉄強磁性粉末粒子内に添加成分としてコ
バルトを主体的に含有する盤状強磁性粉末、およびオキ
シアルキルアミンの存在下で第二鉄塩とアルカリを反応
させ水酸化第二鉄を生成させ、得られた水酸化第二鉄の
スラリーを水熱処理して盤状のα−ＦｅＯＯＩＩを生成
させ、得られた盤状α−Ｆｅ’００ Ｈを非還元性雰囲
気中で加熱して盤状のα−Ｆｅ、Ｏ，とした後、該α−
Ｆｅ、Ｏ，を還元ガス雰囲気中で還元して盤状Ｆｅ２Ｏ
４とし、さらに再酸化して盤状γ−Ｐｅ２０１とした後
、得られた盤状ｒ −ＦｅｔＯ，粉末をコバルト塩また
はコバルト塩と第一鉄塩を含む溶液あるいはアルカリ溶
液の一方に分散させ、分散液に他方を加えて反応させる
ことにより盤状γ−ＦｅｌＯ＝粒子の表面にコバルトを
主体的に含む層を形成し、続いて３００〜６００℃で加
熱処理してコバルト含有盤状酸化鉄強磁性粉末を生成さ
せることを特徴とする盤状強磁性粉末の製造法に関する
ものである。In the present invention, the particle shape is disc-shaped, and the particle diameter (disc diameter) is 0.0.
A disc-shaped ferromagnetic powder that mainly contains cobalt as an additive component in disc-shaped iron oxide ferromagnetic powder particles having a disc-shaped ratio (particle size/thickness) of 3 to 1 μm and a disc ratio (particle size/thickness) of 3 to 10, and an oxyalkyl A ferric salt and an alkali are reacted in the presence of an amine to produce ferric hydroxide, and the resulting slurry of ferric hydroxide is hydrothermally treated to produce plate-shaped α-FeOOII. After heating the plate-shaped α-Fe'00H in a non-reducing atmosphere to form the plate-shaped α-Fe, O,
Platy-shaped Fe2O is obtained by reducing Fe, O, in a reducing gas atmosphere.
4 and further re-oxidized to obtain plate-like γ-Pe201, the obtained plate-like r-FetO, powder is dispersed in either a cobalt salt, a solution containing a cobalt salt and a ferrous salt, or an alkaline solution, By adding the other to the dispersion and causing a reaction, a layer containing mainly cobalt is formed on the surface of the disc-shaped γ-FelO=particles, and then heat-treated at 300 to 600°C to form a cobalt-containing disc-shaped iron oxide strong layer. The present invention relates to a method for producing disc-shaped ferromagnetic powder, which is characterized by producing magnetic powder.
本発明の盤状強磁性粉末およびその製造法についてさら
に詳細に説明する。The disc-shaped ferromagnetic powder of the present invention and its manufacturing method will be explained in more detail.
本発明において、盤状α−Ｆｅ００Ｈを得るための第二
鉄塩としては一般に硫酸第二鉄、塩化第二鉄、硝酸第二
鉄等が使用されるが、これらのなかでも塩化第二鉄が好
適である。アルカリとしては水酸化ナトリウム、水酸化
カリウム等の苛性アルカリが好適に使用される。第二鉄
塩とアルカリを水性媒体中で反応させる方法としては、
第２鉄塩水溶液とアルカリ水溶液を用いる方法が好適で
ある。In the present invention, ferric sulfate, ferric chloride, ferric nitrate, etc. are generally used as ferric salts to obtain disc-like α-Fe00H, and among these, ferric chloride is used. suitable. As the alkali, caustic alkalis such as sodium hydroxide and potassium hydroxide are preferably used. As a method for reacting ferric salt and alkali in an aqueous medium,
A method using an aqueous ferric salt solution and an aqueous alkaline solution is preferred.
その際水溶液中で、第二鉄塩の濃度は０．１〜１モル／
ｌになるように調製するのが適当であり、また苛性アル
カリの濃度は０．３〜５モル／ｌになるように調製する
のが適当である。また第二鉄塩に対する苛性アルカリの
使用量は１〜５倍当量程度にするのが好適である。At that time, the concentration of ferric salt in the aqueous solution is 0.1 to 1 mol/
The concentration of caustic alkali is suitably adjusted to be 0.3 to 5 mol/l. The amount of caustic alkali to be used is preferably about 1 to 5 times equivalent to the ferric salt.
本発明において盤状α−ＦｅＯＯＩＩを得るにあたって
は、特に第二鉄塩とアルカリを反応させて水酸化第二鉄
を生成させる際に、水性媒体中にオキシアルキルアミン
を存在させることが効果的である。In the present invention, in order to obtain disc-shaped α-FeOOII, it is effective to have an oxyalkylamine present in the aqueous medium, especially when reacting a ferric salt with an alkali to produce ferric hydroxide. be.
オキシアルキルアミンは、溶媒に熔解させて、例えば水
の如き溶媒に溶解させて添加してもアルカリ水溶液に溶
解させて添加しても、また直接系内に添加してもよいが
、その量は普通には、第二鉄塩に対して３０〜８０倍モ
ル、好ましくは３５〜７５倍モルになるようにするのが
よい。オキシアルキルアミンの量が少なすぎると粒状に
なったり、粒度分布幅が広くなったりする傾向があり、
また過度に多く用いた場合、α−ＦｅｚＯ３が生成した
りまた経済的でない。The oxyalkylamine may be added dissolved in a solvent such as water, dissolved in an alkaline aqueous solution, or added directly into the system, but the amount Generally, the amount should be 30 to 80 times, preferably 35 to 75 times, by mole relative to the ferric salt. If the amount of oxyalkylamine is too small, it tends to become granular or have a wide particle size distribution.
Further, if it is used in an excessively large amount, α-FezO3 may be produced, which is also uneconomical.
オキシアルキルアミンとしては、アルキル基の炭素数が
２〜６のものが好適であり、その代表例としてはモノエ
タノールアミン、Ｔ−プロパツールアミン、β−プロパ
ツールアミン、ジェタノールアミン、トリエタノールア
ミン、イソブタノールアミン等を挙げることができ、な
かでもエタノールアミンは好適である。As the oxyalkylamines, those in which the alkyl group has 2 to 6 carbon atoms are suitable, and typical examples thereof include monoethanolamine, T-propanolamine, β-propanolamine, jetanolamine, and triethanolamine. , isobutanolamine, etc., among which ethanolamine is preferred.
オキシアルキルアミンの存在下で第二鉄塩とアルカリと
反応させて水酸化第二鉄を生成させる際の反応温度は５
０℃以下、好ましくは０〜４５℃にするのが、オキシア
ルキルアミンの効果を高め、盤状比、粒子形態等をコン
トロールするうえで好適である。温度が高すぎると粒子
が長大化したり、α−Ｆｅ２Ｏ．が混在したり、粒子形
態のバラツキが大きくなったりしやすく、また過度に低
くしても特に利点はない。また反応時間は特に制限され
ないが、一般には１〜２０時間の範囲から適宜選択され
る。The reaction temperature for producing ferric hydroxide by reacting a ferric salt with an alkali in the presence of an oxyalkylamine is 5
The temperature is preferably 0°C or lower, preferably 0 to 45°C, in order to enhance the effect of the oxyalkylamine and to control the disc ratio, particle morphology, etc. If the temperature is too high, the particles may become long or α-Fe2O. It is easy for the particles to be mixed together or the particle morphology to vary greatly, and there is no particular advantage even if it is set too low. Further, the reaction time is not particularly limited, but is generally appropriately selected from the range of 1 to 20 hours.
第二鉄塩と苛性アルカリとの反応によって得られる水酸
化第二鉄のスラリーは、これをただちに水熱処理しても
盤状のゲーサイトを生成させることができるが水熱処理
にさきだって熟成すると形態の揃った盤状粒子が得られ
易（なる。熟成方法としては２Ｏ〜８０℃で５〜３０時
間程度撹拌または撹拌せずに放置する方法が一般に採用
される。A slurry of ferric hydroxide obtained by the reaction of a ferric salt and a caustic alkali can produce plate-shaped goethite even if it is immediately hydrothermally treated, but if it is aged before the hydrothermal treatment, the slurry becomes It is easy to obtain plate-like particles with uniform grains. As a ripening method, a method of stirring or leaving without stirring at 20 to 80° C. for about 5 to 30 hours is generally adopted.
また水熱処理効果を高めるためには、スラリーのｐＨを
１０以上好ましくは１０．５〜１４にして水熱処理する
のが望ましい。スラリーのｐＨを１０以上に調整する方
法としては、例えば水酸化第二鉄を生成させたスラリー
を濾過、洗浄、あるいは上澄液を除去した後、水酸化ナ
トリウム、水酸化カリウム等のアルカリを用いて調整す
る方法が便利である。In order to enhance the hydrothermal treatment effect, it is desirable to conduct the hydrothermal treatment at a pH of 10 or more, preferably from 10.5 to 14. To adjust the pH of the slurry to 10 or higher, for example, after filtering or washing the slurry containing ferric hydroxide, or removing the supernatant liquid, use an alkali such as sodium hydroxide or potassium hydroxide. It is convenient to adjust the
水熱処理温度は、１００〜２５０℃好ましくは１２０〜
２３０℃が好適である。水熱処理温度が低すぎると水酸
化第二鉄をα−ＰｅＯＱｌ（に変換させるのに長時間を
要し、また粒子が細長くなったり、形態のバラツキが大
きくなったりし、水熱処理温度が高すぎるとα−Ｆｅ２
Ｏ３が生成したりする。水熱処理時間は、特に制限され
ないが一般には０．５〜５時間程度である。The hydrothermal treatment temperature is 100 to 250°C, preferably 120 to 250°C.
230°C is preferred. If the hydrothermal treatment temperature is too low, it will take a long time to convert ferric hydroxide into α-PeOQl(), and the particles will become elongated or have a large variation in morphology, and if the hydrothermal treatment temperature is too high. and α-Fe2
O3 is generated. The hydrothermal treatment time is not particularly limited, but is generally about 0.5 to 5 hours.
また水熱処理には、一般にオートクレーブが好適に採用
される。水熱処理することによってスラリー中の水酸化
第二鉄は、従来にない粒子形態を有する粒度が揃った分
散性のよい盤状特に六角盤状ないしそれに近似した形状
のα−ＦｅｚＯ３Ｉに変換される。水熱処理後のスラリ
ーから盤状α−Ｆｅ００Ｈ粒子を回収する方法としては
、水洗、濾過、乾燥等の通常の方法を採用することがで
きる。得られた盤状粒子がα−Ｆｅ００Ｈの結晶構造を
もつことはＸ線回折により確認される。Further, an autoclave is generally suitably employed for the hydrothermal treatment. By the hydrothermal treatment, the ferric hydroxide in the slurry is converted into α-FezO3I having an unprecedented particle morphology, uniform particle size, and good dispersibility, particularly a hexagonal disk shape or a shape similar to it. As a method for recovering the plate-like α-Fe00H particles from the slurry after the hydrothermal treatment, conventional methods such as washing with water, filtration, drying, etc. can be employed. It is confirmed by X-ray diffraction that the obtained disc-like particles have a crystal structure of α-Fe00H.
また、この盤状α−Ｆｅ００Ｈ粉末の粒子径（Ｉ！１径
）、盤状比（粒子径／厚み）等は、製造条件によってか
なり広範囲にかえることができるが、透過型電子顕微鏡
（ＴＥＭ）で盤状α−ＦｅＯＯＨ粒子を観察、測定する
と、粒子形態はほとんど六角盤状であり、平均粒子径は
０．０３〜１μｍの範囲、平均盤状比は３〜１０の範囲
でコントロールでき、それぞれ粒度の揃ったものである
。盤状のα−ＦｅＯＱ旧よ六角盤状ないしそれに近似し
た形状を有し、人込の短辺と長辺との長さの比（長辺／
短辺）は４以下、大部分の粒子は２以下である。In addition, the particle diameter (I!1 diameter), disc ratio (particle diameter/thickness), etc. of this disc-shaped α-Fe00H powder can be varied over a wide range depending on the manufacturing conditions, but Observation and measurement of disc-shaped α-FeOOH particles revealed that the particle morphology was mostly hexagonal disc-shaped, the average particle diameter was in the range of 0.03 to 1 μm, and the average disc-like ratio could be controlled in the range of 3 to 10. It has uniform particle size. The disk-shaped α-FeOQ has a hexagonal disk shape or a shape similar to the old one, and the ratio of the length of the short side to the long side of the crowd (long side /
(short side) is 4 or less, and most of the particles are 2 or less.
盤状のα−Ｆｅ００Ｈを非還元性雰囲気、例えば空気、
窒素ガス等中で加熱処理して盤状のα−Ｆｅ２Ｏ３とす
る際の加熱温度は４００〜９００℃、好ましくは５００
〜８００℃が適当である。非還元性雰囲気中の加熱処理
温度が低すぎると盤状α−Ｆｅｚｅｓ粒子の結晶性の度
合が高められた実質的に高密度な粒子にならなかったり
し、これを還元すると、空孔等のための形状の崩れが大
きくなりＨｃの低下を招く原因ともなる。一方、加熱温
度が高すぎると盤状粒子の変形と粒子および粒子相互間
の焼結をひき起こしてしまう。そのうえ精度の高い設備
、高度な技術を必要とし、工業的に経済的でない。Plasty α-Fe00H is placed in a non-reducing atmosphere, such as air,
The heating temperature when heating in nitrogen gas etc. to form a plate-shaped α-Fe2O3 is 400 to 900°C, preferably 500°C.
~800°C is suitable. If the heat treatment temperature in a non-reducing atmosphere is too low, the plate-shaped α-Fezes particles may not become substantially dense particles with an increased degree of crystallinity; Therefore, the deformation of the shape becomes large, which causes a decrease in Hc. On the other hand, if the heating temperature is too high, it will cause deformation of the plate-like particles and sintering of the particles and each other. Moreover, it requires highly accurate equipment and advanced technology, and is not industrially economical.
また、盤状α−Ｐｅｔ’ｓを還元ガス雰囲気、例えば水
素、水素と窒素の混合ガス中で還元して盤状Ｆｅ２Ｏ４
にする際の温度は２５０℃以上で行うと、有効な磁気特
性を有するものが得られ、加熱温度の上昇とともに反応
が促進されるが、過度に高い温度に加熱すると焼結が起
り保磁力が低下するため一般には２５０〜５５０℃、好
ましくは３５０〜５５０℃の範囲内で行なうのが適当で
ある。次に還元に続いて一般には２００〜４００℃、好
ましくは２５０〜３５０℃で再酸化してγ−Ｆｅ２Ｏ３
を得る。このようにして得られた盤状γ−ＦｅｚＯｉ粉
末は、次にコバルト塩、またはコバルト塩と第一鉄塩を
含む溶液中に分散させ、さらにこれにアルカリ水溶液を
加えて反応を行なうと、粒子表面にコバルトを主体的に
含有する、盤状酸化鉄（ｒ−Ｆｅｔｕｓ）が得られる。In addition, the plate-shaped α-Pet's can be reduced in a reducing gas atmosphere, such as hydrogen or a mixed gas of hydrogen and nitrogen to form a plate-shaped Fe2O4.
If the heating temperature is 250°C or higher, a product with effective magnetic properties will be obtained, and the reaction will be accelerated as the heating temperature increases, but if heated to an excessively high temperature, sintering will occur and the coercive force will decrease. Generally, it is appropriate to carry out the temperature within the range of 250 to 550°C, preferably 350 to 550°C. The reduction is then generally followed by reoxidation at 200-400°C, preferably 250-350°C to form γ-Fe2O3.
get. The plate-shaped γ-FezOi powder obtained in this way is then dispersed in a solution containing a cobalt salt or a cobalt salt and a ferrous salt, and an aqueous alkali solution is further added thereto to carry out a reaction, resulting in particles. Platy iron oxide (r-Fetus) whose surface mainly contains cobalt is obtained.
好ましくはないが、アルカリ水溶液に盤状ｒ −Ｆｅ２
Ｏ３粉末を分散させ、コバルト塩またはコバルト塩と第
一鉄塩を含む溶液を加えてもほぼ同様の結果が得られる
。Although it is not preferable, if a plate-shaped r -Fe2 is added to an alkaline aqueous solution,
Similar results can be obtained by dispersing O3 powder and adding a cobalt salt or a solution containing a cobalt salt and a ferrous salt.
コバルト塩としては硫酸コバルト、塩化コバルト、硝酸
コバルト等がまた第一鉄塩としては硫酸第一鉄、塩化第
一鉄、硝酸第−鉄等が好適なものとして使用され、アル
カリ水溶液としては、水酸化ナトリウム、水酸化カリウ
ム等の苛性アルカリ水溶液が好適なものとして使用され
る。反応温度は反応を均一に進行させるため、５０℃以
下であることが好ましい。このようにして得られた盤状
γ−Ｆｅ２０３強磁性粉末を洗浄、ろ別、乾燥した後加
熱処理を行なう。コバルトを粒子内部に拡散させる（ド
ープする）加熱処理温度としては３００〜６００℃の範
囲でよい。好ましくは、３５０〜５００℃である。３０
０℃より高い温度であれば、コバルトの粒子内部への拡
散は起こるが反応を速やかに進行させるため、３５０℃
以上が好ましい。３５０℃より高い温度であれば、コバ
ルトの粒子内部への拡散は速やかに進行し、５００℃以
上にしても特にそれ以上の効果は認められない。Suitable cobalt salts include cobalt sulfate, cobalt chloride, cobalt nitrate, etc., and ferrous salts include ferrous sulfate, ferrous chloride, and ferrous nitrate. Aqueous caustic alkaline solutions such as sodium oxide and potassium hydroxide are preferably used. The reaction temperature is preferably 50° C. or lower in order to allow the reaction to proceed uniformly. The plate-shaped γ-Fe203 ferromagnetic powder thus obtained is washed, filtered, dried, and then heat-treated. The heat treatment temperature for diffusing (doping) cobalt inside the particles may be in the range of 300 to 600°C. Preferably it is 350-500°C. 30
If the temperature is higher than 0°C, cobalt will diffuse into the particles, but in order to speed up the reaction, the temperature is 350°C.
The above is preferable. If the temperature is higher than 350°C, the diffusion of cobalt into the interior of the particles will proceed rapidly, and even if the temperature is higher than 500°C, no further effect will be observed.
本発明によって、従来にない粒子形態の盤状強磁性粉末
およびその製造法が提供される。本発明に係る、コバル
トを粒子内に含有したコバルト含有盤状酸化鉄強磁性粉
末は従来にない盤状、詳しくは六角盤状ないしそれに近
似した形状を有し、粒子径が０．０３〜１μｍ盤状比が
３〜ＩＯの範囲にあり粒度分布が均一であるという特長
を有し、きわめてすぐれた磁気特性を示す。The present invention provides a disk-shaped ferromagnetic powder with an unprecedented particle form and a method for producing the same. The cobalt-containing disk-shaped iron oxide ferromagnetic powder containing cobalt in the particles according to the present invention has an unprecedented disk shape, more specifically, a hexagonal disk shape or a shape similar to it, and a particle size of 0.03 to 1 μm. It has a disk ratio in the range of 3 to IO, a uniform particle size distribution, and exhibits extremely excellent magnetic properties.
次にこの発明の実施例について説明する。Next, embodiments of this invention will be described.
実施例１
塩化第二鉄（ＦｅＣ１ｉ ・６８ｚＯ） １００ｇを蒸
留水２１に溶解させて８℃に保持した溶液を、水酸化ナ
トリウム１５０ｇおよびモノエタノールアミン１０００
ｔａｌ（塩化第二鉄に対して４５倍モル）を蒸留水４
１に溶解させ、１０℃に保持した溶液中に滴下し、約ｌ
θ℃に保持しながら十分に攪拌して反応させ水酸化第二
鉄スラリーを得た。Example 1 A solution in which 100 g of ferric chloride (FeC1i 68zO) was dissolved in distilled water 21 and kept at 8°C was mixed with 150 g of sodium hydroxide and 1000 g of monoethanolamine.
tal (45 times mole relative to ferric chloride) in distilled water 4
1 and dropped into a solution kept at 10°C, about 1
While maintaining the temperature at θ°C, the mixture was sufficiently stirred and reacted to obtain a ferric hydroxide slurry.
このスラリーを３０℃で約２０時間放置して熟成した後
、上澄液を除去し、濃度１０％の水酸化ナトリウム水溶
液で洗浄してスラリーのｐＨを１１に調整し、スラリー
を内容１００１００Ｏ！のオートクレーブに仕込み、１
５０℃で１時間水熱処理を施し、盤状ゲーサイトスラリ
ーを得た。After this slurry was left to mature at 30°C for about 20 hours, the supernatant was removed and washed with a 10% sodium hydroxide aqueous solution to adjust the pH of the slurry to 11. Put it in an autoclave, 1
Hydrothermal treatment was performed at 50° C. for 1 hour to obtain a plate-shaped goethite slurry.
盤状ゲートサイトスラリーは、これを水洗、濾過、乾燥
して粉末状で第１図に示すような六角盤状の盤状ゲーサ
イトを得た。The plate-shaped gatesite slurry was washed with water, filtered, and dried to obtain a hexagonal plate-shaped goethite in powder form as shown in FIG.
得られた盤状ゲーサイトの粉末の透過型電子顕微鏡写真
１０万倍（５万倍を２倍に拡大）を第１図に示す。また
Ｘ線回折による分析でこの盤状ゲーサイトは、α−Ｐｅ
００Ｈ構造であることが確認された。A transmission electron micrograph of the obtained disc-shaped goethite powder is shown in FIG. In addition, analysis by X-ray diffraction revealed that this platy goethite was α-Pe
It was confirmed that it had a 00H structure.
盤状ゲーサイトは透過型電子顕微鏡（ＴＥＭ）により観
察し、粒子径（盤径）、盤状比（粒子径／厚み）等を測
定した。これらの結果を比表面積の測定結果とともに第
１表に示す。なお第１表中平均粒子径および平均盤状比
は、粒子３０個についての平均値である。The platy goethite was observed using a transmission electron microscope (TEM), and the particle diameter (disc diameter), disc ratio (particle diameter/thickness), etc. were measured. These results are shown in Table 1 together with the specific surface area measurement results. Note that the average particle diameter and average platelet ratio in Table 1 are average values for 30 particles.
実施例２〜６
実施例１の塩化第二鉄に対するモノエタノールアミンの
使用量を４５倍モルから５５倍モルにかえ（実施例２）
、実施例１の水酸化第二鉄を生成させる際の温度を１０
℃から２０℃にかえ（実施例３）、実施例１の水熱処理
温度を１５０℃から１８０℃にかえ（実施例４）、実施
例１のモノエタノールアミンのかわりにβ−プロパツー
ルアミンを使用しく実施例５）、実施例１のモノエタノ
ールアミンのかわりにジェタノールアミンを使用しく実
施例６）、その他の条件は実施例１と同様にして盤状ゲ
ーサイトを得た。実施例４で得られた盤状ゲーサイトの
粉末の透過型電子顕微鏡写真（１０万倍に拡大）を第２
図に示す。Examples 2 to 6 The amount of monoethanolamine used in Example 1 was changed from 45 times the mole to 55 times the amount of ferric chloride (Example 2)
, the temperature when producing ferric hydroxide in Example 1 was set to 10
℃ to 20℃ (Example 3), the hydrothermal treatment temperature in Example 1 was changed from 150℃ to 180℃ (Example 4), and β-propaturamine was used instead of monoethanolamine in Example 1. A platy goethite was obtained in the same manner as in Example 1 except that Example 5) and Example 6) used jetanolamine instead of monoethanolamine in Example 1. A second transmission electron micrograph (100,000 times magnified) of the plate-like goethite powder obtained in Example 4
As shown in the figure.
実施例１と同様にして測定した結果を第１表に示す。Table 1 shows the results measured in the same manner as in Example 1.
実施例７
実施例１で得られた盤状α−Ｆｅ００Ｂ粉末３０ｇを空
気中６００℃で１時間加熱してα−Ｆｅ、Ｏ，粉末を生
成しこのＩＸ Ｐｅｔ’ｓ粉末を水素ガス（５Ｉｔ／
ｗｉｎ）により、３００℃で還元してＦｅ２Ｏ．粉末を
得さらに、これを空気中で２５０℃の温度で再酸化し平
均粒子径０．０９μｍｓ平均盤状比３．３比表面積３２
ｎ？／ｇ、保磁力２３００ｅ 、 ｆｉｌ和磁化７２ｅ
ａ＋ｕ／ｇの盤状Ｔ−Ｆｅ２Ｏ．粉末を得た。Example 7 30 g of the plate-shaped α-Fe00B powder obtained in Example 1 was heated in air at 600°C for 1 hour to produce α-Fe, O, powder, and this IX Pet's powder was heated with hydrogen gas (5 It/min).
win) at 300°C to form Fe2O. The obtained powder was further reoxidized in air at a temperature of 250°C to obtain an average particle size of 0.09 μm, an average platelet ratio of 3.3, and a specific surface area of 32.
n? /g, coercive force 2300e, fil sum magnetization 72e
a+u/g plate-like T-Fe2O. A powder was obtained.
次いでこのｒ−Ｆｅｔｕｓ粉末２７ｇを硫酸コバルト０
．０１４モルと硫酸第一鉄０．０４モルとが溶解された
水溶液ｌｌ中に分散させ、これに０．５４モルの水酸化
ナトリウムを溶解させた水酸化ナトリウム水溶液Ｉｆを
加えた。この分散液の温度を４５℃まで昇温しこの温度
を保持したままで、６時間攪拌を続けた。次いでろ別し
、充分に水洗して反応溶液を除去した後、１２０℃で乾
燥しさらに大気中に於いて、４００℃で４時間加熱処理
を施し、粒子内にコバルトを含有するコバルト含有盤状
酸化鉄強磁性粉末を得た。Next, 27g of this r-Fetus powder was added with 0 cobalt sulfate.
．． 0.14 mole of ferrous sulfate and 0.04 mole of ferrous sulfate were dispersed in 11 of an aqueous solution, and to this was added an aqueous sodium hydroxide solution If in which 0.54 mole of sodium hydroxide was dissolved. The temperature of this dispersion was raised to 45° C., and stirring was continued for 6 hours while maintaining this temperature. Next, the reaction solution was removed by filtration, thoroughly washed with water, dried at 120°C, and further heat-treated at 400°C for 4 hours in the atmosphere to form cobalt-containing discs containing cobalt within the particles. Iron oxide ferromagnetic powder was obtained.
このようにして得られたコバルト含有盤状酸化鉄強磁性
粉末は平均粒子径が０．１ ｐ ｍ、平均盤状比が２．
９、比表面積が２６ｒｒｒ／ｇ、保磁力が６８００ｅで
コバルト原子の含有量は粉末全体に対して２．５ｗｔ％
であった。The cobalt-containing disc-shaped iron oxide ferromagnetic powder thus obtained has an average particle diameter of 0.1 pm and an average disc-like ratio of 2.
9. Specific surface area is 26rrr/g, coercive force is 6800e, and cobalt atom content is 2.5wt% based on the entire powder.
Met.
実施例−８
実施例−３で得られた盤状α−ＦｅＯＯＨ粉末を用いた
他は実施例７と同様にしてコバルト含有盤状酸化鉄強磁
性粉末を得た。Example-8 A cobalt-containing disc-shaped iron oxide ferromagnetic powder was obtained in the same manner as in Example 7, except that the disc-shaped α-FeOOH powder obtained in Example-3 was used.
実施例−９
実施例−７において、コバルト含有酸化鉄粉末を得る過
程において硫酸コバルトの使用量を０．０２８モル、硫
酸第一鉄の使用量を０．０８モルとした以外は、実施例
２と同様にしてコバルト含有盤状酸化鉄強磁性粉末を得
た。Example-9 Example 2 except that in Example-7, the amount of cobalt sulfate used was 0.028 mol and the amount of ferrous sulfate was 0.08 mol in the process of obtaining cobalt-containing iron oxide powder. Cobalt-containing disc-shaped iron oxide ferromagnetic powder was obtained in the same manner as above.
実施例−７−８，９で得られた強磁性粉末の特性を第２
表に示す。The characteristics of the ferromagnetic powder obtained in Examples 7-8 and 9 were
Shown in the table.
臥下余白 第 １ 表 第 ２ 表bed margin Table 1 Table 2
第１図および第２図は、本発明の実施例１および実施例
４で得られた盤状ゲーサイトの粒子形態を１０万倍に拡
大した粒子の透過型電子顕微鏡写真である。FIG. 1 and FIG. 2 are transmission electron micrographs of the particle morphology of plate-like goethite obtained in Example 1 and Example 4 of the present invention, magnified 100,000 times.
Claims (2)
１μｍ、盤状比（粒子径／厚み）が３〜１０の範囲にあ
る盤状酸化鉄強磁性粉末粒子内に添加成分としてコバル
トを主体的に含有する盤状強磁性粉末。(1) Particle shape is disc-like and particle diameter (disc diameter) is 0.03~
A disc-shaped ferromagnetic powder mainly containing cobalt as an additive component in disc-shaped iron oxide ferromagnetic powder particles having a diameter of 1 μm and a disc ratio (particle diameter/thickness) in the range of 3 to 10.
アルカリとを反応させて、水酸化第二鉄を生成させ、得
られた水酸化第二鉄のスラリーを水熱処理して盤状α−
ＦｅＯＯＨを得る工程と、 ｂ）上記工程ａ）で得られた盤状α−ＦｅＯＯＨを非還
元性雰囲気中で加熱処理して盤状α−Ｆｅ＿２Ｏ＿３と
した後、該α−Ｆｅ＿２Ｏ＿３を還元性ガス雰囲気中で
還元して盤状Ｆｅ＿３Ｏ＿４とし、さらに再酸化して盤
状γ−Ｆｅ＿２Ｏ＿３を得る工程と、ｃ）上記工程ｂ）
で得られた盤状γ−Ｆｅ＿２Ｏ＿３粉末をコバルト塩ま
たはコバルト塩および第一鉄塩を含む溶液あるいはアル
カリ溶液の一方に分散させ、分散液に他方を加えて盤状
γ−Ｆｅ＿２Ｏ＿３粒子の表面にコバルトを主体的に含
む層を、形成させ、これを洗浄、濾別、乾燥して得られ
た該粒子を、３００〜６００℃で加熱処理を行ないコバ
ルトを粒子内に含有した盤状強磁性粉末を得る工程と、
を含んでなる盤状強磁性粉末の製造法。(2) a) React a ferric salt with an alkali in the presence of an oxyalkylamine to generate ferric hydroxide, and hydrothermally treat the resulting slurry of ferric hydroxide to form a plate. α−
a step of obtaining FeOOH; b) After heating the plate-like α-FeOOH obtained in step a) above in a non-reducing atmosphere to form a plate-like α-Fe_2O_3, the α-Fe_2O_3 is heated in a reducing gas atmosphere. c) step b) of the above step b).
The plate-like γ-Fe_2O_3 powder obtained in step 1 is dispersed in either a cobalt salt, a solution containing a cobalt salt and a ferrous salt, or an alkaline solution, and the other is added to the dispersion to coat the surface of the plate-like γ-Fe_2O_3 particles with cobalt. A layer containing mainly cobalt is formed, and the particles obtained by washing, filtering, and drying are heat-treated at 300 to 600°C to obtain a disc-shaped ferromagnetic powder containing cobalt in the particles. The process of obtaining
A method for producing a disc-shaped ferromagnetic powder comprising.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60106826A JPS61266313A (en) | 1985-05-21 | 1985-05-21 | Discoid ferromagnetic powder and its production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60106826A JPS61266313A (en) | 1985-05-21 | 1985-05-21 | Discoid ferromagnetic powder and its production |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61266313A true JPS61266313A (en) | 1986-11-26 |
Family
ID=14443573
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60106826A Pending JPS61266313A (en) | 1985-05-21 | 1985-05-21 | Discoid ferromagnetic powder and its production |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61266313A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1045136C (en) * | 1994-03-07 | 1999-09-15 | 中国科学院山西煤炭化学研究所 | Super-fine magnetic powder and its prepn. method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS616127A (en) * | 1984-04-12 | 1986-01-11 | バスフ アクチエン ゲゼルシヤフト | Manufacture of cobalt-containing isotropic magnetic iron oxide |
-
1985
- 1985-05-21 JP JP60106826A patent/JPS61266313A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS616127A (en) * | 1984-04-12 | 1986-01-11 | バスフ アクチエン ゲゼルシヤフト | Manufacture of cobalt-containing isotropic magnetic iron oxide |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1045136C (en) * | 1994-03-07 | 1999-09-15 | 中国科学院山西煤炭化学研究所 | Super-fine magnetic powder and its prepn. method |
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