JP2735885B2 - Method for producing metal magnetic powder for magnetic recording - Google Patents
Method for producing metal magnetic powder for magnetic recordingInfo
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- JP2735885B2 JP2735885B2 JP1173838A JP17383889A JP2735885B2 JP 2735885 B2 JP2735885 B2 JP 2735885B2 JP 1173838 A JP1173838 A JP 1173838A JP 17383889 A JP17383889 A JP 17383889A JP 2735885 B2 JP2735885 B2 JP 2735885B2
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- magnetic powder
- metal
- magnetic
- metal magnetic
- magnetic recording
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は高密度磁気記録に適した、微細な磁気記録用
金属磁性粉末（以下金属磁性粉末と記す）の製造方法に
関するものである。さらに詳しくは、８ミリビデオテー
プ、ビデオフロッピー、その他高密度磁気記録媒体用の
磁性材料として最適な保磁力、高飽和磁束密度を有し、
微細でかつ分散性に優れる、鉄を主成分とする金属磁性
粉末の製造法に関するものである。Description: TECHNICAL FIELD The present invention relates to a method for producing fine metal magnetic powder for magnetic recording (hereinafter referred to as metal magnetic powder) suitable for high-density magnetic recording. More specifically, it has an optimal coercive force and high saturation magnetic flux density as a magnetic material for 8 mm video tape, video floppy, and other high-density magnetic recording media,
The present invention relates to a method for producing a metal magnetic powder containing iron as a main component, which is fine and excellent in dispersibility.
従来、磁気記録用磁性粉として、γ−Fe2O3、Co含有
γ−Fe2O3、CrO2等が使用されてきたが、近年の磁気記
録媒体の高密度記録化の要望に沿う磁性材料として、鉄
を主体とする金属磁性粉末が使用されている。Conventionally, γ-Fe 2 O 3 , Co-containing γ-Fe 2 O 3 , CrO 2 and the like have been used as magnetic powders for magnetic recording. As a material, metal magnetic powder mainly composed of iron is used.
このような金属磁性粉末の製造方法としては次のよう
な方法が検討されてきた。The following method has been studied as a method for producing such a metal magnetic powder.
（１） 金属の有機酸塩（主としてシュウ酸塩）を加熱
分解し、還元性気体で還元する方法。(1) A method in which a metal organic acid salt (mainly oxalate) is thermally decomposed and reduced with a reducing gas.
（２） 金属カルボニル化合物を分解する方法。(2) A method for decomposing a metal carbonyl compound.
（３） 水銀電解によって金属磁性粉末を電析させる方
法。(3) A method of depositing a metal magnetic powder by mercury electrolysis.
（４） 強磁性金属塩をその溶液中で水素化ホウ素ナト
リウム等で湿式還元する方法。(4) A method of performing wet reduction of a ferromagnetic metal salt with sodium borohydride or the like in the solution.
（５） 衝撃大電流を通じて、放電爆発によって金属磁
性粉末を生じさせる方法。(5) A method in which a metal magnetic powder is generated by a discharge explosion through a high impact current.
（６） 強磁性金属、合金を不活性ガス中で蒸発させる
方法。(6) A method of evaporating a ferromagnetic metal or alloy in an inert gas.
（７） オキシ水酸化鉄或いはこれらに他の金属（例え
ばCo、Ni）をドープさせたもの、或いは酸化鉄、又はフ
ェライト組成酸化物を還元性気体で還元する方法。(7) A method in which iron oxyhydroxide or a material obtained by doping the same with another metal (for example, Co or Ni), or an iron oxide or an oxide containing ferrite is reduced with a reducing gas.
これら金属磁性粉末の種々製法の中で、コスト及び性
能面から、（７）の製造方法が主流となっており、本発
明もこの分類に属する。Among the various methods for producing metal magnetic powders, the method (7) is the mainstream in terms of cost and performance, and the present invention also belongs to this category.
従来から、この方法よって高密度磁気記録媒体に適し
た種々物性、磁気特性を備えた金属磁性粉の開発が行わ
れ、オーディオ用メタルテープ、８ミリビデオ用メタル
テープ、ビデオ用フロッピー等に使用されているが、近
年、オーディオのデジタル化、ハイバンド８ミリビデオ
の開発、高密度メモリー用フロッピー等の開発に伴い、
さらに高性能の磁気記録媒体の開発が望まれている。即
ち、磁気記録媒体の高出力特性、及びノイズレベルの低
下が要求されている。磁気記録媒体のこれらの諸特性は
磁気記録媒体に使用する磁性材料の特性と密接な関係が
あり、高密度磁気記録媒体の磁性粉の具備すべき主な特
性として次の項目があげられる。Conventionally, metal magnetic powders having various physical properties and magnetic properties suitable for high-density magnetic recording media have been developed by this method, and are used for audio metal tapes, 8 mm video metal tapes, video floppies, and the like. However, in recent years, with the digitization of audio, the development of high-band 8mm video, and the development of floppy disks for high-density memory,
There is a demand for the development of a magnetic recording medium with higher performance. That is, high output characteristics of the magnetic recording medium and a reduction in noise level are required. These characteristics of the magnetic recording medium are closely related to the characteristics of the magnetic material used for the magnetic recording medium, and the following items can be mentioned as the main characteristics that the magnetic powder of the high-density magnetic recording medium should have.
ａ 適切な保磁力（Hc）を持つこと。a Have an appropriate coercive force (Hc).
ｂ 飽和磁束密度（σｓ）が大きいこと。b The saturation magnetic flux density (σs) must be large.
ｃ 角型比（σr/σｓ）が大きいこと。c Squareness ratio (σr / σs) is large.
ｄ 粒子サイズが小さく、且つ揃っていること。d The particle size is small and uniform.
ｅ 緻密な構造をもち、分散が容易であること。e It must have a dense structure and be easily dispersed.
ｆ テープ化後耐候性に富むこと。f Having excellent weather resistance after tape formation.
磁気記録媒体として高出力特性を得る為には、磁性材
料に対してa,b,c,eの項目が特に求められる。項目ａの
保磁力は磁気記録媒体の使用目的にあった数値にコント
ロールする必要があり、その方法としては出発原料であ
るオキシ水酸化鉄の粒子サイズをコントロールすること
が主に行われる。In order to obtain high output characteristics as a magnetic recording medium, items a, b, c, and e are particularly required for magnetic materials. It is necessary to control the coercive force of item a to a value suitable for the purpose of use of the magnetic recording medium. As a method for controlling the coercive force, the particle size of iron oxyhydroxide as a starting material is mainly controlled.
ｂの飽和磁束密度は、その数値が大きいことが金属磁
性粉末の特徴であるが、還元したままでの金属磁性粉末
は活性が大きく、大気中に取り出すと、大気中の酸素と
急激な反応を起こして磁性のないα酸化鉄に変化してし
まう。その為還元後の金属磁性粉末は大気に触れる前
に、粒子の表面に酸化被膜を形成させる処理をして、大
気中で安全に取り扱えるようにしている。この酸化被膜
の磁性は弱く、単位粒子当たりに占める割合が多くなる
と飽和磁束密度は小さくなってしまう。特に、磁気記録
媒体の低ノイズ化を目的として金属磁性粉末の粒子の微
細化を進めると顕著に飽和磁束密度は低下する。The characteristic of the metal magnetic powder is that the saturation magnetic flux density of b is large, but the metal magnetic powder as it is reduced has a large activity, and when it is taken out into the atmosphere, it suddenly reacts with oxygen in the atmosphere. It is changed to α iron oxide without magnetism. Therefore, the metal magnetic powder after reduction is treated to form an oxide film on the surface of the particles before being exposed to the atmosphere, so that it can be handled safely in the atmosphere. The magnetism of the oxide film is weak, and the saturation magnetic flux density decreases as the proportion of the oxide film per unit particle increases. In particular, when the size of the metal magnetic powder is reduced for the purpose of reducing the noise of the magnetic recording medium, the saturation magnetic flux density is remarkably reduced.
項目ｃの角型比を大きくする為には原料オキシ水酸化
鉄の針状比を大きくし、粒子サイズを揃えることが重要
であるが、針状比については項目ａの保磁力との関係も
考慮してコントロールされる。さらに角型比の向上は、
還元時の粒子形状の崩れ、粒子の切断、焼結をどのよう
に防ぐかが重要である。項目ｅに関しては、金属磁性微
粒子中に空孔がなく緻密で、表面平滑性の良いものが望
まれている。In order to increase the squareness ratio of item c, it is important to increase the acicular ratio of the raw material iron oxyhydroxide and make the particle size uniform, but the acicular ratio also has a relationship with the coercive force of item a. It is controlled in consideration. Further improvement of squareness ratio
It is important how to prevent the collapse of the particle shape during the reduction, the cutting and sintering of the particles. Regarding item e, it is desired that the metal magnetic fine particles have no pores and are dense and have good surface smoothness.
磁気記録媒体の低ノイズ化を達成する為には、金属磁
性粉を微細化して、磁気記録媒体の単位体積当たりの粒
子数を多くすることが重要である。一般にテープのS/N
（出力−ノイズ比）は、塗布される磁性粉の粒子サイ
ズ、分散性、充填性、及びテープの表面の平滑性によっ
て左右される。表面性、分散性が一定である場合、S/N
は単位体積当たりの平均粒子数の平方根に比例すること
が知られている。従って、粒子サイズはできるだく小さ
く、しかも高充填性の磁性粉ほど有利といえる。（玉
川、中鉢、日本応用磁気学会誌Vol.7、No.3、1983、P20
4） しかし、金属磁性粉粒子の微細化は、前述したよう
に、飽和磁束密度の低下につながり、かつ比表面積の増
大により粒子の凝集性が高まり分散が難しくなる方向に
ある。In order to reduce the noise of the magnetic recording medium, it is important to reduce the size of the metal magnetic powder to increase the number of particles per unit volume of the magnetic recording medium. Generally S / N of tape
(Output-noise ratio) depends on the particle size, dispersibility, filling property, and smoothness of the tape surface of the applied magnetic powder. When surface properties and dispersibility are constant, S / N
Is known to be proportional to the square root of the average number of particles per unit volume. Therefore, it can be said that a magnetic powder having as small a particle size as possible and having a higher filling property is more advantageous. (Tamagawa, Nakabachi, Journal of the Japan Society of Applied Magnetics Vol.7, No.3, 1983, P20
4) However, as described above, the miniaturization of the metal magnetic powder particles leads to a decrease in the saturation magnetic flux density, and the increase in the specific surface area tends to increase the cohesiveness of the particles, making dispersion difficult.
このように、金属磁性粉末を微細化し、且つ高飽和磁
束密度を有し、さらに分散性と媒体の耐候性に優れる金
属磁性粉末が要望されているが、これら多くの要求を満
たす金属磁性粉末は現在までのところ製造されていな
い。As described above, there is a demand for a metal magnetic powder that is finer, has a high saturation magnetic flux density, and is excellent in dispersibility and weather resistance of a medium. Not manufactured to date.
本発明の目的は以上のような従来技術の問題点を解決
することにあり、磁気記録媒体の種類に応じた最適な保
磁力と、微細でありながら高飽和磁束密度を有し、分散
性に優れ、磁気記録媒体にした時の耐候性に優れる金属
磁性粉末を製造することにある。An object of the present invention is to solve the above-mentioned problems of the prior art, and has an optimum coercive force according to the type of magnetic recording medium, and has a small but high saturation magnetic flux density, and has a high dispersibility. An object of the present invention is to produce a metal magnetic powder having excellent weather resistance when used as a magnetic recording medium.
本発明はニッケル及び亜鉛をドープしたオキシ水酸化
鉄に、コバルト及びニッケルの化合物を被着させる処理
をした後、さらにケイ素及びアルミニウムの化合物を被
着させる処理をし、しかる後当該処理物を加熱処理し、
次いで水素流下で還元することを特徴とする磁気記録用
金属磁性粉末の製造方法である。The present invention performs a treatment for depositing a compound of cobalt and nickel on iron oxyhydroxide doped with nickel and zinc, and then a treatment for depositing a compound of silicon and aluminum, and then heats the treated product. Process,
Next, the present invention provides a method for producing a metal magnetic powder for magnetic recording, which is reduced under a flow of hydrogen.
本発明の方法により製造される金属磁性粉末は、適切
な保磁力（Hc）の範囲にあり、飽和磁束密度（σｓ）及
び角型比が大きいという特徴がある。また、Ｘ線回折装
置でα−Fe（110）面の回折線ピークの半値幅より計算
される結晶子サイズは140〜170Åと微細であり、且つ焼
結および空孔のない、分散性に優れた金属磁性粉末であ
る。The metal magnetic powder produced by the method of the present invention is characterized by being in an appropriate coercive force (Hc) range, and having a large saturation magnetic flux density (σs) and a large squareness ratio. The crystallite size calculated from the half-width of the diffraction line peak on the α-Fe (110) plane by an X-ray diffractometer is as fine as 140 to 170 °, and has excellent sintering and vacancy-free dispersibility. Metal magnetic powder.
本発明に用いるニッケル及び亜鉛をドープしたオキシ
水酸化鉄とは平均長軸長が0.15〜0.7μｍであり、平均
短軸長が0.015〜0.05μｍの、ニッケル及び亜鉛をドー
プしたα−FeOOH、β−FeOOH及びγ−FeOOHを指すが、
製品の微細化、高飽和磁束密度化の諸要求を考慮した場
合、この中でも特に好ましいのはα−FeOOHである。但
し、β−FeOOH及びγ−FeOOHであっても差し支えない。Nickel and zinc-doped iron oxyhydroxide used in the present invention has an average major axis length of 0.15 to 0.7 μm and an average minor axis length of 0.015 to 0.05 μm, nickel- and zinc-doped α-FeOOH, β -FeOOH and γ-FeOOH,
In view of various requirements for miniaturization and high saturation magnetic flux density of the product, α-FeOOH is particularly preferable among them. However, β-FeOOH and γ-FeOOH may be used.
また本発明で用いるCo、Ni、Si及びAlの化合物は水可
溶性のもの、もしくはコロイド状のものであればいずれ
も使用できる。好適に使用される化合物としては、CoCl
2、NiCl2、AlCl3のような塩化物、CoSO4、NiSO4のよう
な硫酸塩、及び硝酸塩などの塩類、あるいはこれらの部
分水酸化物、水ガラス、コロイダルシリカ、アルミン酸
ナトリウム、アルミナゾル等を挙げることができる。The compounds of Co, Ni, Si and Al used in the present invention may be any of water-soluble or colloidal compounds. Compounds that are preferably used include CoCl
2, chlorides such as NiCl 2, AlCl 3, CoSO 4, sulfates such as NiSO 4, and salts such as nitrates or these portions hydroxide, water glass, colloidal silica, sodium aluminate, alumina sol and the like Can be mentioned.
本発明においては、先ずコバルト及びニッケルの化合
物をニッケル及び亜鉛をドープしたオキシ水酸化鉄に被
着させるのであるが、この被着は以下の方法により行
う。すなわち、Co及びNiの化合物として水可溶性塩を用
いるときは、これを水に溶解させ、あらかじめ水に分散
させておいた前記オキシ水酸化鉄あるいは酸化鉄のスラ
リーに添加する。次いで、上記可溶性塩がアルカリ性な
らば、塩酸、硫酸、リン酸等の酸を、また可溶性塩が酸
性ならば、苛性ソーダ、苛性カリ、アンモニア等のアル
カリを適宜添加して、Co及びNiの水酸化物又は酸化物を
被着させる。In the present invention, first, a compound of cobalt and nickel is deposited on iron oxyhydroxide doped with nickel and zinc. This deposition is performed by the following method. That is, when a water-soluble salt is used as the compound of Co and Ni, this is dissolved in water and added to the iron oxyhydroxide or iron oxide slurry previously dispersed in water. Next, if the soluble salt is alkaline, an acid such as hydrochloric acid, sulfuric acid or phosphoric acid is added, and if the soluble salt is acidic, an alkali such as caustic soda, caustic potash, or ammonia is appropriately added to obtain a hydroxide of Co and Ni. Alternatively, an oxide is deposited.
Co及びNiの添加目的は、還元後の金属磁性粉の飽和磁
束密度増加、及び耐酸化性の向上、分散性の向上である
が、これらの効果は本発明の後の工程、すなわち、Si及
びAl化合物を被着し、当該処理物を熱処理し、次いで還
元する工程と組み合わせて初めて発現するものである。The purpose of adding Co and Ni is to increase the saturation magnetic flux density of the metal magnetic powder after reduction, and to improve oxidation resistance and dispersibility.These effects are obtained in the later steps of the present invention, namely, Si and It appears only in combination with the steps of applying an Al compound, heat treating the treated product, and then reducing it.
次いで、当該処理液に、Si及びAl化合物を添加し、前
記と同様に添加した化合物の種類に応じて、酸又はアル
カリで中和してSi及びAl化合物を当該処理物の上にさら
に被着させる。Si及びAlの被着は、還元時の焼結を防止
するのが目的であり、添加量が少なすぎては焼結防止の
効果がなく、また多すぎるとSi及びAlが磁性を持たない
ため飽和磁束密度が低下してしまう。Next, Si and Al compounds are added to the treatment liquid, and neutralized with an acid or an alkali according to the kind of the compound added in the same manner as described above to further deposit the Si and Al compounds on the treated material. Let it. The purpose of the deposition of Si and Al is to prevent sintering during reduction, and if the addition amount is too small, there is no effect of preventing sintering, and if it is too large, Si and Al do not have magnetism. The saturation magnetic flux density decreases.
以上の被着処理が終了した後、当該処理物を濾過し、
十分に洗浄する。After the above deposition process is completed, the processed material is filtered,
Wash thoroughly.
洗浄の終了した当該処理物を乾燥し、次いで非還元性
雰囲気、例えば、空気中あるいは窒素等の不活性ガス中
で熱処理をする。この熱処理の温度は500〜850℃が好ま
しく、温度が低い場合には熱処理の効果がなく、また高
すぎる場合には、熱処理の段階で粒子の形状が変化して
製品の特性が低下する。The treated product after the cleaning is dried, and then heat-treated in a non-reducing atmosphere, for example, in air or an inert gas such as nitrogen. The temperature of this heat treatment is preferably 500 to 850 ° C. If the temperature is too low, the effect of the heat treatment is not obtained. If the temperature is too high, the shape of the particles changes during the heat treatment and the characteristics of the product are deteriorated.
次いで、当該処理物を還元反応器に仕込み、水素流下
で還元するのであるが、還元温度が低すぎると反応時間
が長くなり経済的ではなくなる。また温度が高い場合は
反応時間は短くなるが、金属磁性粉末が焼結し、保磁力
及び角型比の低下をきたし、さらに媒体にした時のノイ
ズレベルが高いものになってしまう。従って還元温度の
選択は重要であるが、本発明の方法における還元温度は
300〜600℃の範囲が好ましい。Next, the treated product is charged into a reduction reactor and reduced under a flow of hydrogen. If the reduction temperature is too low, the reaction time becomes longer, which is not economical. When the temperature is high, the reaction time is short, but the metal magnetic powder is sintered, the coercive force and the squareness are reduced, and the noise level when used as a medium is high. Therefore, the choice of the reduction temperature is important, but the reduction temperature in the method of the present invention is
A range from 300 to 600 ° C is preferred.
還元後は還元反応器を冷却し、窒素と空気の混合ガス
を流す等常法により金属磁性粉末を安定化して系外へと
り出す。After the reduction, the reduction reactor is cooled, and the metal magnetic powder is stabilized and taken out of the system by an ordinary method such as flowing a mixed gas of nitrogen and air.
このようにして製造された金属磁性粉は平均長軸長が
0.15〜0.4μｍ、平均短軸長が0.015〜0.03μｍ、針状比
は７〜15で、またＸ線回折装置でα−Fe（110）面の回
折線ピークの半値幅より計算される結晶子サイズが140
〜170Åと微細であり、且つ保磁力は1350〜16500e、飽
和磁束密度は125〜145emu/gである。The metal magnetic powder produced in this way has an average major axis length.
0.15-0.4 μm, average minor axis length 0.015-0.03 μm, needle ratio 7-15, and crystallite calculated from the half-width of the diffraction line peak of α-Fe (110) plane by X-ray diffractometer Size 140
It is as fine as ~ 170 °, the coercive force is 1350 ~ 16500e, and the saturation magnetic flux density is 125 ~ 145emu / g.
尚、本発明においてオキシ水酸化鉄に対するニッケル
及び亜鉛の好ましいドープ量は各々オキシ水酸化鉄中の
鉄に対してニッケルが0.5〜5.0重量％、亜鉛が0.3〜5.0
重量％である。In the present invention, the preferable doping amounts of nickel and zinc with respect to the iron oxyhydroxide are 0.5 to 5.0% by weight of nickel and 0.3 to 5.0% by weight of the iron in the iron oxyhydroxide.
% By weight.
また、コバルト及びニッケル、及びケイ素及びアルミ
ニウム化合物の被着量は前記ニッケル及び亜鉛がドープ
されたオキシ水酸化鉄中の鉄に対してコバルトが2.0〜3
0重量％、ニッケルが1.0〜20重量％、ケイ素が0.3〜７
重量％、アルミニウムが0.5〜10重量％が好ましい範囲
である。Further, the amount of cobalt and nickel, and the amount of silicon and aluminum compound to be deposited is 2.0 to 3 with respect to iron in the nickel and zinc-doped iron oxyhydroxide.
0 wt%, nickel is 1.0-20 wt%, silicon is 0.3-7
The preferred ranges are 0.5% by weight and 0.5-10% by weight of aluminum.
次に本発明を実施例を以て説明する。 Next, the present invention will be described with reference to examples.
実施例１ 平均短軸長0.02μｍ、平均長軸長0.26μｍ、針状比13
で、ニッケルを2.0重量％（対鉄）、亜鉛を1.5重量％
（対鉄）ドープしたα−FeOOH150gを30の蒸溜水に入
れてよく分散した。これに、別に用意した塩化コバルト
および塩化ニッケルの各0.08モルを300mlの蒸溜水に溶
解した液を入れてよく攪拌した。次いで、2Nの苛性ソー
ダ水溶液を１時間かけて滴下して、pH＝８まで中和し
た。次いで0.105モルの塩化アルミニウムを溶解した水
溶液１を加えて30分間よく攪拌した。次にけい酸ナト
リウムを0.05モル溶解した水溶液500mlを２時間かけて
ゆっくり滴下し、続いて2Nの苛性ソーダ液を滴下してpH
＝８まで中和した。この後１時間攪拌を続け、該被着ゲ
ーサイトを水洗、濾過して、CoおよびNi化合物とSiおよ
びAl化合物被着ゲーサイトを得た。乾燥後、該被着ゲー
サイトを650℃の電気炉中で２時間加熱処理した。次に
該熱処理物を水素ガス気流中で、460℃の温度で５時間
還元した。還元終了後、反応系のガスを窒素ガスに変え
て、室温まで冷却した後、空気を徐々に送入して該還元
物を安定化して金属磁性粉末を得た。該金属磁性粉末の
組成分析を蛍光Ｘ線分析装置を用いて行ったところ、鉄
に対する重量％で、Co＝5.1、Ni＝7.1、Si＝1.5、Al＝
3.0であった。Example 1 Average minor axis length 0.02 μm, average major axis length 0.26 μm, needle ratio 13
2.0% by weight of nickel (to iron) and 1.5% by weight of zinc
150 g of (to iron) -doped α-FeOOH was placed in 30 distilled water and dispersed well. A solution prepared by dissolving 0.08 mol of each of separately prepared cobalt chloride and nickel chloride in 300 ml of distilled water was added thereto, and the mixture was stirred well. Then, a 2N aqueous sodium hydroxide solution was added dropwise over 1 hour to neutralize to pH = 8. Next, an aqueous solution 1 in which 0.105 mol of aluminum chloride was dissolved was added, and the mixture was stirred well for 30 minutes. Next, 500 ml of an aqueous solution in which 0.05 mol of sodium silicate was dissolved was slowly added dropwise over 2 hours, and then 2N caustic soda solution was added dropwise to adjust the pH.
= 8. Thereafter, stirring was continued for 1 hour, and the attached goethite was washed with water and filtered to obtain a Co and Ni compound and a Si and Al compound attached goethite. After drying, the attached goethite was heated in an electric furnace at 650 ° C. for 2 hours. Next, the heat-treated product was reduced in a hydrogen gas stream at a temperature of 460 ° C. for 5 hours. After completion of the reduction, the gas in the reaction system was changed to nitrogen gas and cooled to room temperature, and then air was gradually fed in to stabilize the reduced product to obtain a metal magnetic powder. When the composition analysis of the metal magnetic powder was performed using an X-ray fluorescence spectrometer, Co = 5.1, Ni = 7.1, Si = 1.5, Al =
3.0.
該金属磁性粉末を試料振動型磁力計（東英工業製VS
M）により最大磁場10KOeで磁気特性を測定したところ、
保磁力（Hc）＝15800e、飽和磁束密度（σｓ）＝137emu
/g、角型比＝0.517であった。また該金属磁性粉末の結
晶子サイズを求めたところ159Åであった（測定法＝Ｘ
線回折装置でα−Fe（110）面の回折線ピークの半値幅
より算出）。さらに透過電子顕微鏡（TEM）により該金
属磁性粉末の粒子形態を調べたところ、焼結および空孔
のない、平均針状比10の針状性の良好な金属粒子であっ
た。この結果より、磁気記録媒体用の磁性材料として良
好な特性であることが確認された。The metal magnetic powder was used as a sample vibration magnetometer (VS.
M) measured the magnetic properties with a maximum magnetic field of 10KOe,
Coercive force (Hc) = 15800e, saturation magnetic flux density (σs) = 137emu
/ g, squareness ratio = 0.517. The crystallite size of the metal magnetic powder was 159 ° (measurement method = X
(Calculated from the half width of the diffraction line peak on the α-Fe (110) plane by a line diffraction apparatus.) Further, the particle morphology of the metal magnetic powder was examined by a transmission electron microscope (TEM). As a result, the metal particles were free from sintering and voids and had good needle-like properties with an average needle-like ratio of 10. From these results, it was confirmed that the magnetic material had good characteristics as a magnetic material for a magnetic recording medium.
次いで、該金属磁性粉末を塩化ビニル−酢酸ビニル共
重合樹脂を溶解した溶液に、分散剤、滑剤、研磨剤と共
に入れて分散し、これにウレタンエラストマーを添加混
合して分散を十分に行った。該分散塗料に架橋剤を添加
して十分混合した後、グラビアコーターにより14μｍの
PETフィルム上に塗布し、磁性塗料が未乾燥の状態で、2
500ガウスの磁石で磁場配向処理を行い、さらに乾燥
後、スーパーカレンダー処理を行って、8mm幅にスリッ
トして８ミリビデオ用テープを製造した。該テープの磁
気特性をVSMにより最大磁場10KOeで測定したところ、Hc
＝15480e、Br＝2840G、Bm＝3381G、Br/Bm＝0.82であっ
た。Next, the metal magnetic powder was dispersed in a solution in which a vinyl chloride-vinyl acetate copolymer resin was dissolved together with a dispersing agent, a lubricant, and an abrasive, and a urethane elastomer was added thereto and mixed to sufficiently disperse. After adding a cross-linking agent to the dispersion paint and mixing well, 14 μm of gravure coater was used.
Apply on PET film and leave the magnetic paint dry.
A magnetic field orientation treatment was performed with a 500 gauss magnet, and after drying, a super calender treatment was performed, and slits were formed to a width of 8 mm to produce an 8 mm video tape. When the magnetic properties of the tape were measured by a VSM at a maximum magnetic field of 10 KOe, Hc
= 15480 e, Br = 2840 G, Bm = 3381 G, Br / Bm = 0.82.
また、該8mmにスリットしたテープを温度60℃、相対
温度90％の恒温恒湿槽に１週間入れて、劣化促進テスト
を行い、VSMでテープのBmを測定したところ3.208Gであ
り、 は5.1％であった。In addition, the tape slit to 8 mm was placed in a thermo-hygrostat at a temperature of 60 ° C. and a relative temperature of 90% for one week, a deterioration promotion test was performed, and the Bm of the tape measured by VSM was 3.208 G. Was 5.1%.
原料オキシ水酸化鉄にドープされている金属とそのド
ープ量及び被着金属とその被着量、熱処理温度を表−１
に、還元後の金属磁性粉末の磁気特性、比表面積値（窒
素吸着法）及び結晶子の大きさ、テープの磁気特性及び
Bmの劣化率（ΔBmと表示）を表−２に示した。Table 1 shows the metal doped in the raw material iron oxyhydroxide, its doping amount, the deposited metal, its deposited amount, and the heat treatment temperature.
The magnetic properties, specific surface area (nitrogen adsorption method) and crystallite size of the reduced metallic magnetic powder, the magnetic properties of the tape,
Table 2 shows the deterioration rate of Bm (denoted as ΔBm).
以下の実施例、比較例でSi及びAlを被着する場合は、
本実施例の方法で被着した。When Si and Al are applied in the following Examples and Comparative Examples,
It was applied by the method of this example.
実施例２〜４ 原料α−FeOOH中にドープしたNi及び亜鉛の鉄に対す
る重量％、被着金属の鉄に対する重量％、熱処理温度を
表−１に示した。被着処理以下の工程は実施例１に準じ
て実施した。Examples 2 to 4 Table 1 shows the weight percent of Ni and zinc doped in the raw material α-FeOOH with respect to iron, the weight percent of iron to be deposited with respect to iron, and the heat treatment temperature. The following steps were performed in accordance with Example 1.
還元後の金属磁性粉末の磁気特性及び比表面積値、結
晶子、テープにした時の磁気特性、テープのBm劣化率
（ΔBmと表示）を表−２に示した。Table 2 shows the magnetic properties and specific surface area values of the reduced metallic magnetic powder, crystallites, magnetic properties when formed into a tape, and the Bm deterioration rate of the tape (denoted as ΔBm).
比較例１ 原料としてニッケル及び亜鉛をドープしてないα−Fe
OOHを使用して実施例１と同じ被着処理を行った。その
後の処理も全て実施例１と同じに実施した。ドープ金属
が存在していない為ゲーサイトの形状が不揃いであり、
分散が悪かった。Comparative Example 1 α-Fe not doped with nickel and zinc as a raw material
The same deposition treatment as in Example 1 was performed using OOH. All subsequent processes were performed in the same manner as in Example 1. Since no doped metal exists, the shape of goethite is irregular,
Dispersion was poor.
比較例２ ケイ素及びアルミニウムの被着を行わなかった以外は
実施例１と同じに実施した。粒子の焼結が起こり、保磁
力、角型比の低下が顕著であった。さらに、焼結が進行
している為結晶子も大きく分散も悪かった。Comparative Example 2 The same operation as in Example 1 was performed except that silicon and aluminum were not applied. Sintering of the particles occurred, and the coercive force and the squareness ratio were remarkably reduced. Furthermore, the crystallites were large and the dispersion was poor due to the progress of sintering.
比較例３ 実施例３と同じα−FeOOHを原料にし、コバルト及び
ニッケルの被着を省いて、ケイ素及びアルミニウムを被
着したものであるが、金属磁性粉末の飽和磁束密度が低
く、テープでのBrも低いものとなった。さらにテープの
ΔBmも大きく酸化安定性の劣るものであった。Comparative Example 3 The same α-FeOOH as in Example 3 was used as a raw material, and the deposition of cobalt and nickel was omitted, and silicon and aluminum were deposited. However, the saturation magnetic flux density of the metal magnetic powder was low, and Br was also low. Further, ΔBm of the tape was large and the oxidation stability was poor.
比較例４ 実施例２で熱処理を省いて還元したものであるが、実
施例２に比較して金属磁性粉のHc、結晶子、テープの角
型比で劣るものとなった。Comparative Example 4 Reduction was performed by omitting the heat treatment in Example 2, but the metal magnetic powder was inferior in Hc, crystallite, and squareness ratio of the tape as compared with Example 2.
以上の比較例１〜４の原料オキシ水酸化鉄にドープさ
れている金属とそのドープ量及び被着金属とその被着
量、熱処理温度を表−１に、還元後の金属磁性粉末の磁
気特性、比表面積値及び結晶子の大きさ、テープの磁気
特性及びBmの劣化率を表−２に示した。Table 1 shows the metal doped in the raw material iron oxyhydroxide of Comparative Examples 1 to 4, the amount of the metal doped, the amount of the metal deposited, the amount of the metal deposited, and the heat treatment temperature. Table 1 shows the magnetic properties of the reduced metal magnetic powder. , Specific surface area and crystallite size, magnetic properties of the tape, and Bm degradation rate are shown in Table-2.
〔発明の効果〕 実施例、比較例で明らかなように、本発明の方法で製
造した金属磁性粉末は、高飽和磁束密度と高角型比を有
し、且つ結晶子も小さく分散性に優れているもので、且
つテープの耐酸化安定性にも優れる高密度磁気記録媒体
に適した極めて高性能のものである。 [Effects of the Invention] As is clear from the examples and comparative examples, the metal magnetic powder produced by the method of the present invention has a high saturation magnetic flux density and a high squareness ratio, and has a small crystallite and excellent dispersibility. This is an extremely high performance suitable for a high-density magnetic recording medium having excellent tape oxidation stability.
Claims (1)
化鉄に、コバルト及びニッケルの化合物を被着させる処
理をした後、さらにケイ素及びアルミニウムの化合物を
被着させる処理をし、しかる後当該処理物を加熱処理
し、次いで水素流下で還元することを特徴とする磁気記
録用金属磁性粉末の製造方法。1. A treatment for depositing a compound of cobalt and nickel on iron oxyhydroxide doped with nickel and zinc, followed by a treatment for depositing a compound of silicon and aluminum, and then the treated product Is subjected to a heat treatment and then reduced under a stream of hydrogen to produce a metal magnetic powder for magnetic recording.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1173838A JP2735885B2 (en) | 1989-07-05 | 1989-07-05 | Method for producing metal magnetic powder for magnetic recording |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1173838A JP2735885B2 (en) | 1989-07-05 | 1989-07-05 | Method for producing metal magnetic powder for magnetic recording |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0338005A JPH0338005A (en) | 1991-02-19 |
| JP2735885B2 true JP2735885B2 (en) | 1998-04-02 |
Family
ID=15968095
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1173838A Expired - Fee Related JP2735885B2 (en) | 1989-07-05 | 1989-07-05 | Method for producing metal magnetic powder for magnetic recording |
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| Country | Link |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59145706A (en) * | 1983-02-08 | 1984-08-21 | Toyo Soda Mfg Co Ltd | Production of magnetic metallic powder |
| JPS60135506A (en) * | 1983-12-22 | 1985-07-18 | Toyo Soda Mfg Co Ltd | Production of ferromagnetic metallic powder |
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| Publication number | Publication date |
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