JPS606081B2 - Method for producing acicular oxide magnetic material - Google Patents

Description

【発明の詳細な説明】 本発明は磁気テープなどに使用される酸化物磁性材料の
製造方法に関し、特に針状Ｑ−Ｆｅ００日微粒子を核晶
として、その表面にｙ−Ｆｅ００日を生成させ、この微
粒子をｙ−Ｆｅ２０３に変態させることにより、磁性塗
料中における分散性を極めて良好にし、充てん性及び配
向性を高めた針状酸化物磁性材料の製造方法である。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an oxide magnetic material used for magnetic tapes, etc., and in particular, by using acicular Q-Fe00 day fine particles as a nucleus crystal, producing y-Fe00 day on the surface thereof, By transforming these fine particles into y-Fe203, the present invention is a method for producing an acicular oxide magnetic material that has extremely good dispersibility in a magnetic paint and has improved filling properties and orientation.

従釆、磁気テープなどの磁気記録媒体に使用される酸化
物磁性材料はｈ一般には４・田−カムラス法によって得
た針状Ｑ−Ｆｅ００日粒子を還元してＦｅ３０４とし、
これを酸化してｙ−Ｆｅ２０３に変態させる方法により
得られて来た。In general, oxide magnetic materials used in magnetic recording media such as magnetic tapes are made by reducing acicular Q-Fe00 particles obtained by the 4-Ta-Kamuras method to Fe304.
It has been obtained by a method of oxidizing this and transforming it into y-Fe203.

しかしこの方法によると針状Ｑ−Ｆｅ００日粒子の形状
のコントロールは容易であり、また安定してｙ−Ｆｅ２
０３を製造することができるが、Ｑ−Ｆｅ００日粒子の
生成に際して針状粒子の技分れが必然的に生じ、これが
充てん性或は配向性の向上に対する支障となっていた。However, according to this method, it is easy to control the shape of the acicular Q-Fe00 day particles, and the y-Fe2
However, during the production of Q-Fe 00-day particles, the acicular particles were inevitably divided, which was a hindrance to improving the filling property or orientation.

そして又、この方法によって得られたｙ−Ｆｅ２０３の
磁性塗料中における分散性は必ずしも良好とは言えなか
った。磁性材料であるｙ−Ｆｅ２０３の分散性、充てん
性及び配向性の向上は磁気テープにおける感度．再生出
力の向上、或いはノイズレベルの低減に大きく寄与する
ものである。本発明は、このような問題点を解決するた
めになされたものであり、針状Ｑ−Ｆｅ００日微粒子を
核晶として、その表面にｙ−Ｆｅ００日を生成させるこ
とによりＱ−Ｆｅ００印粒子の針状性を継承することで
容易に針状比が大きく形のととのった粒子を得ることが
でき、ｙ−Ｆｅ２０３とした時の保磁力も４０比お程度
まで高めることも可能であり、高分散性で充てん性、配
同性の良好なｙ一Ｆｅ２０３からなる酸化物磁性材料を
製造する方法を提供するものである。Furthermore, the dispersibility of y-Fe203 obtained by this method in the magnetic paint was not necessarily good. The improved dispersibility, filling properties, and orientation of y-Fe203, a magnetic material, improve the sensitivity of magnetic tapes. This greatly contributes to improving reproduction output or reducing noise level. The present invention has been made to solve these problems, and uses acicular Q-Fe00-day fine particles as a nucleus crystal to generate y-Fe00-day particles on the surface of the Q-Fe00-marked particles. By inheriting the acicularity, it is possible to easily obtain particles with a large acicularity ratio and a sharp shape, and it is also possible to increase the coercive force to about 40 ratio when using y-Fe203, making it highly dispersible. The present invention provides a method for producing an oxide magnetic material made of y-Fe203 that has good properties, filling properties, and coordination properties.

本発明は針状Ｑ−Ｆｅ００日微粒子を水に分散したスラ
リー溶液に塩化第一鉄の水溶液を加え、さらに塩化第一
鉄の１／２当量以下のアルカリ溶液を加え、生じたＦｅ
（ＯＨ）２コロイドを３０℃以下の温度で激しくかくは
ん酸化させることにより針状Ｑ−Ｆｅ００日微粒子の表
面にｙ−Ｆｅ００日を生成させｖ この微粒子を加熱脱
水し、さらに還元．酸化することに特徴がある。In the present invention, an aqueous solution of ferrous chloride is added to a slurry solution in which acicular Q-Fe 00-day fine particles are dispersed in water, and an alkaline solution of 1/2 equivalent or less of ferrous chloride is further added, and the resulting Fe
By vigorously stirring and oxidizing (OH)2 colloid at a temperature below 30°C, y-Fe00 day is generated on the surface of acicular Q-Fe00 day fine particles.v The fine particles are heated and dehydrated, and further reduced. It is characterized by oxidation.

これにより針状比が大きく形のととのった分散性の良好
なｙ−Ｆｅ２０３を得ることができる。以下本発明を具
体的に説明する。This makes it possible to obtain y-Fe203 with a large acicular ratio, a well-shaped shape, and good dispersibility. The present invention will be specifically explained below.

従来知られている方法により得られた針状Ｑ−Ｆｅ００
日微粒子が榛晶として使用され、針状比１０：１以上、
最軸０．５〆以下のものが好ましい。Acicular Q-Fe00 obtained by a conventionally known method
Sun particulates are used as sac crystals, with an acicular ratio of 10:1 or more,
The maximum axis is preferably 0.5 or less.

この針状Ｑ−Ｆｅ００日微粒子を水に良く分散したスラ
リー溶液に塩化第一鉄水溶液を加え、引き続きかくはん
を継続する。加える塩化第一鉄の量は、生成させようと
するｙ−Ｆｅ００日量によって決められ、核晶の針状Ｑ
−Ｆｅ００日微粒子１モルに対してｙ−Ｆｅ００日を２
モル生成させようとする場合、塩化第一鉄４モルを加え
る。塩化第一鉄水溶液に続いてもアルカリ溶液を加えＦ
ｅ（ＯＨ）２コロイドを生成し、激しくかくはんし必要
な場合は酸素含有ガス（例えば空気）を吹き込み〜Ｆｅ
２（ＯＨ）２を酸化させてｙ−Ｆｅ００日を生成させる
。ｙ−Ｆｅ００日を生成させる条件として溶液のＰＨ及
び反応温度が重要であり〜塩化第一鉄に対して１／２当
量以下のアルカリの添加、即ち溶液の初期ＰＨを７．５
以下とする。また反応温度は３０℃以下２に維持しなけ
ればならない。ＰＨが７．５以上或いは反応温度が３０
℃以上の場合は、ｙ−Ｆｅ００日が生成されずＦｅ３０
４が生成されてしまう。塩化第一鉄に対して１／２当量
以下のアルカリ量であればも良Ｐち溶液の初期ＰＨが７
．５以下であればｙ−３Ｆｅ００日が生成されるが「
アルカリ量の減少に伴ない塩化第一鉄に対するｙ−Ｆｅ
００日の生成収率が低下するため塩化第一鉄に対して１
ノ２当量のアルカリを加えるのが好ましい。アルカリと
してＮａＯＨ，ＫＯＨ，ＮＨ４０日，Ｃａ（ＯＨ）２な
どが使用３される。Ｆｅ（ＯＨ）２コロイドが酸化され
ｙ−Ｆｅ００日が生成されると反応溶液はオレンジ色を
帯びた黄色となり反応は完了する。A ferrous chloride aqueous solution is added to a slurry solution in which the acicular Q-Fe 00 day fine particles are well dispersed in water, and stirring is continued. The amount of ferrous chloride to be added is determined by the daily amount of y-Fe00 to be produced.
-Fe00 days y-Fe00 days for 1 mole of fine particles
If you want to generate moles, add 4 moles of ferrous chloride. Add an alkaline solution to the ferrous chloride aqueous solution and F
Generate e(OH)2 colloid, stir vigorously and blow in oxygen-containing gas (e.g. air) if necessary ~Fe
2(OH)2 is oxidized to produce y-Fe00 day. The pH of the solution and the reaction temperature are important as conditions for producing y-Fe00 days. ~ Addition of 1/2 equivalent or less of alkali to ferrous chloride, that is, the initial pH of the solution is set to 7.5.
The following shall apply. Further, the reaction temperature must be maintained at 30° C. or lower. pH is 7.5 or higher or reaction temperature is 30
If the temperature is above ℃, y-Fe00 day is not generated and Fe30
4 will be generated. Even if the amount of alkali is less than 1/2 equivalent to ferrous chloride, the initial pH of the solution is 7.
．． If it is less than 5, y-3Fe00 days will be generated, but "
y-Fe relative to ferrous chloride as the amount of alkali decreases
1 for ferrous chloride because the production yield on day 00 decreases.
Preferably, 2 equivalents of alkali are added. NaOH, KOH, NH40, Ca(OH)2, etc. are used as the alkali. When the Fe(OH)2 colloid is oxidized and y-Fe00 is produced, the reaction solution becomes orange-yellow and the reaction is completed.

この時の溶液のＰＨは３程度であり反応時間は概略３〜
５時間である。 ４生成した沈でん物を区別、水洗した
のち乾燥して針状微粒子が得られる。この針状微粒子の
Ｘ線回折パターンを第１図に示す。図においてａはＡＳ
ＴＭ回折カード１７一５３６によるＱ−Ｆｅ００日のＸ
線回折パターンであり、ｂは同カード８−９８によるｙ
−Ｆｅ００日のパターンである。核晶のＱ−Ｆｅ００Ｈ
Ｉモルに対してそれぞれ１モル「 ２モル「 ３モルの
ｙ−Ｆｅ００日を生成させるように塩化第一鉄を加えて
反応させた場合のＸ線回折パターンがｃ，ｄ，ｅである
。Ｑ一Ｆｅ００Ｈ／ｙ−Ｆｅ００日が１ノ１の場合のｃ
では極く徴量のｙ−Ｆｅ００日が検知されるだけである
が、Ｑ−Ｆｅ００Ｈ／シーＦｅ００日が１／３であるｅ
ではＱ‐Ｆｅ００日の回折パターンはほとんど消去し、
ｙ‐Ｆｅ００日の回折パターンのみとなりＱ−Ｆｅ００
日微粒子の表面がｙ−Ｆｅ００日で充分に覆われている
ことがわかる。乾燥した針状微粒子を粉砕したのち５０
０ｑｏ以下の温度で脱水し「更に通常の方法で還元。The pH of the solution at this time is about 3, and the reaction time is approximately 3~
It is 5 hours. 4. Separate the formed precipitate, wash it with water, and then dry it to obtain needle-like fine particles. The X-ray diffraction pattern of this acicular fine particle is shown in FIG. In the figure, a is AS
Q-Fe00 day X by TM diffraction card 17-536
Line diffraction pattern, b is y according to the same card 8-98
-Fe00 day pattern. Nucleic crystal Q-Fe00H
The X-ray diffraction patterns are c, d, and e when ferrous chloride is added and reacted to produce 1 mol, 2 mol, and 3 mol of y-Fe00 per 1 mol, respectively.Q c when one Fe00H/y-Fe00 day is 1 no 1
In this case, only y-Fe00 day of extremely high concentration is detected, but Q-Fe00H/sea Fe00 day is 1/3 e
Then, the diffraction pattern of Q-Fe00 day almost disappears,
Only the diffraction pattern of y-Fe00 day is Q-Fe00
It can be seen that the surface of the day fine particles is sufficiently covered with y-Fe00 days. After crushing the dried needle-like particles,
It is dehydrated at a temperature below 0qo and further reduced using normal methods.

酸化することによりｙ−Ｆｅ２０３からなる酸化物磁性
材料を得ることができる。本発明におけるｙ−Ｆｅ２０
３の性状を左右する重要な因子のひとつとして綾鼠とな
るＱ−Ｆｅ００日微粒子の形状〜即ちその針状比「粒子
サイズがあげられるが最大の因子は針状ぱ−Ｆｅ００日
微粒子の表面に生成させるｙ−Ｆｅ００日の量である。By oxidizing, an oxide magnetic material made of y-Fe203 can be obtained. y-Fe20 in the present invention
One of the important factors that influences the properties of 3 is the shape of the Q-Fe 00-day fine particles, that is, its acicular ratio. This is the amount of y-Fe produced on day 00.

このｙ−Ｆｅ００日の生成量は核晶であるＱ−Ｆｅ００
日微粒子の表面積、粒子サイズに左右され一義的に規定
できないが、本発明の効果を出す上でその下限はぴ−Ｆ
ｅ００日微粒子の表面を覆うだけのｙ−Ｆｅ００日量が
必要とされ、例えばＸ線回折の結果充分検知されるだけ
のｙ−Ｆｅ００日が生成される必要がある。一方ｙ−Ｆ
ｅ００日生成量の増加に伴ない得られるｙ−Ｆｅ２０３
の分散性は飽和しまた保磁力は低下する懐向を示して来
るので、結局分散性が飽和し保磁力の低下を起さない程
度のｙ−Ｆｅ００日生成島が上限となる。このようにし
て得られたｙ−Ｆｅ２０３からなる針状酸化物磁性材料
は、これを用いて磁性塗料としフィルムベースに塗布し
て磁気テープに加工した場合、印加磁界５００比たで約
０．８のＢｒ／Ｂｍ１２．２以上の配向度（磁気テープ
の長さ方向と中方向のＢｒの比）を示し、良好な角形性
「 配向性を有し、分散性のすぐれていることがわかっ
た。The amount of y-Fe00 produced on day 1 is Q-Fe00, which is the nucleus crystal.
Although it cannot be defined unambiguously because it depends on the surface area and particle size of the microparticles, the lower limit for producing the effects of the present invention is
An amount of y-Fe00 days is required to cover the surface of the e00-day fine particles, and it is necessary to generate enough y-Fe00 days to be sufficiently detected as a result of X-ray diffraction, for example. On the other hand, y-F
y-Fe203 obtained with increasing production amount on e00 day
Since the dispersibility of y-Fe00 is saturated and the coercive force tends to decrease, the upper limit is the y-Fe00 day generation island, which is such that the dispersibility is saturated and the coercive force does not decrease. When the thus obtained acicular oxide magnetic material made of y-Fe203 is used as a magnetic paint and applied to a film base to be processed into a magnetic tape, the applied magnetic field 500 ratio is approximately 0.8 It was found that the magnetic tape had an orientation degree of Br/Bm of 12.2 or more (ratio of Br in the longitudinal direction and the middle direction of the magnetic tape), had good squareness, and had excellent dispersibility.

以下実施例を示す。実施例 １ 長藤の長さが平均０．３山、針状比１０：１の針状蚊−
Ｆｅ００日微粒子（第２図の写真）８９夕を水８ク中に
分散し、これに咳晶となるＱ−Ｆｅ００日の量と表面に
生成するｙ−Ｆｅ００日量がモル比で１：２となるよう
塩化第一鉄（Ｆｅｃ１２．辺も０）８００夕を水５そ中
に溶解したものを加え、かくはんを継続しながらさらに
ＮａＯＨ１６０夕を水２そ中に溶解したものを加える。Examples are shown below. Example 1 Needle-like mosquitoes with an average length of long wisteria of 0.3 peaks and a needle-like ratio of 10:1
89 pieces of Fe00 fine particles (photograph in Figure 2) were dispersed in 8 cups of water, and the amount of Q-Fe00 that became cough crystals and the amount of Y-Fe00 that formed on the surface were mixed in a molar ratio of 1:2. Add 800 ml of ferrous chloride (Fec 12.0) dissolved in 5 ml of water, and then add 160 ml of NaOH dissolved in 2 ml of water while stirring.

そしてこの反応溶液を２０℃の温度に保持して激しくか
くはんを続けた。ＮａＯＨ溶液を加えた直後の反応溶液
のＰＨは７．５であった。約５時間かくはんを続けるこ
とにより溶液はオレンジ色を帯びた黄色に変化しＰＨは
３１とＺなり反応は完了したので生成枕でん物をろ別し
水洗したのち乾燥、粉砕して黄色の微粉末を得た。これ
を電子顕微鏡で観察したところ長軸の長さが平均０．５
り針状比が（１０〜１５）；１の針状微粒子（第３図の
写真）であった。この微粒子を（酸化性雰囲気下）２５
０ｑｏの温度で脱水処理が行ない続いて還元性雰囲気下
３５０℃の温度で還元処理を行ない、さらに酸化性雰囲
気下３００００の温度で酸化処理を行なってｙ−Ｆｅ２
０３を得た。The reaction solution was kept at a temperature of 20° C. and vigorously stirred. The pH of the reaction solution immediately after adding the NaOH solution was 7.5. By continuing to stir for about 5 hours, the solution changed to an orange-yellow color, and the pH reached 31 and Z, indicating that the reaction was complete, so the resulting pulp was filtered out, washed with water, dried, and crushed to give a yellow fine powder. A powder was obtained. When observed with an electron microscope, the average length of the long axis was 0.5
The particles were acicular fine particles with an acicular ratio of (10 to 15):1 (photograph in Figure 3). This fine particle (under oxidizing atmosphere)
Dehydration treatment was performed at a temperature of 0qo, followed by reduction treatment at a temperature of 350℃ in a reducing atmosphere, and further oxidation treatment at a temperature of 30000℃ in an oxidizing atmosphere to obtain y-Fe2.
I got 03.

この磁気特性は保磁力（ＨＣ）が３７のｅ、単位重量あ
たりの飽和磁気モーメソト（ｏｓ）が６段ｍｕ／夕、単
位重量あたりの残留磁気モーメント（〇ｒ）が３準ｍｕ
ノタであった。This magnetic property has a coercive force (HC) of 37 e, a saturation magnetic moment per unit weight (os) of 6 steps mu/h, and a remanent magnetic moment per unit weight (〇r) of 3 quasi-mu.
It was Nota.

このｙ−Ｆｅ２０３を磁性材料として作製した磁気テー
プは保磁力（Ｈｃ）が３３のｅ、飽和磁束密度（Ｂｍ）
が１５０に、残留磁束密度（Ｂｒ）が１２０的、Ｂｒ／
Ｂｍが０．８０配向度が２．４であった。A magnetic tape made using this y-Fe203 as a magnetic material has a coercive force (Hc) of 33e and a saturation magnetic flux density (Bm).
is 150, residual magnetic flux density (Br) is 120, Br/
Bm was 0.80 and degree of orientation was 2.4.

実施例 ２実施例１に用いた針状Ｑ−Ｆｅ００日微粒子
８９夕を水８〆中に分散し、これに核晶のＱ−Ｆｅ００
日の量と生成されるｙ−Ｆｅ００日の量がモル比で１：
３となるように塩化第一鉄（ＦｅＣ１２．４も０）１２
００夕を水５〆中に溶解したものを加え、かくはんを継
続しながらさらにＮａＯＨ２４０夕を水２Ｚ中に溶解し
たものを加え、この反応溶液を２０午０の温度に保持し
て激しくかくはんを続けた。Example 2 89 pieces of acicular Q-Fe00 fine particles used in Example 1 were dispersed in water, and Q-Fe00 of the nucleus crystals were added to this.
The molar ratio of the amount per day and the amount of y-Fe00 produced per day is 1:
Ferrous chloride (FeC12.4 is also 0) 12
A solution of 0.00 ml dissolved in 5 ml of water was added, and while stirring was continued, a solution of 240 ml of NaOH dissolved in 2 z of water was added, and this reaction solution was kept at a temperature of 0.20 ml and continued to be stirred vigorously. Ta.

ＮａＯＨ溶液を加えた直後の反応溶液のＰＨは７．３で
あった。約４時間かくはんを続けることにより溶液はオ
レンジ色に変化しＰＨは２．８となり反応は完了したの
で生成沈でん物をろ別し、水洗したのち乾燥．粉砕して
オレンジ色の微粉末を得た。これを電子顕微鏡で観察し
たところ長較の長さが平均０．６〃、針状比が（１０〜
１５）三１の針状微粒子であった。この微粉末を実施例
１と同様に熱処理してｙ一Ｆｅ２０３とした。その磁気
特性はＨｃが２９のｅ、ｏｓが技鷺ｍｕ／夕、びｒが３
１ｅｍｕノタであった。このｙ−Ｆｅ２０３を磁性材料
として実施例１と同様に作製した磁気テープはＨｃが２
６のｅ、Ｂｍが１３００夕、Ｂｒが１００の、Ｂｒ／Ｂ
ｍが０．７７、配向度が２．３であった。実施例 ３ 現在広く実用に供されている、長軸の長さが平均０．５
山、針状比７三１の針状Ｑ−Ｆｅ００日微粒子を８９夕
とり水８〆中に分散する。The pH of the reaction solution immediately after adding the NaOH solution was 7.3. By continuing to stir for about 4 hours, the solution turned orange and the pH reached 2.8, indicating that the reaction was complete, so the precipitate formed was filtered off, washed with water, and then dried. It was crushed to obtain an orange fine powder. When observed with an electron microscope, the average length of the long chain was 0.6〃, and the needle ratio was (10~
15) It was 31 needle-like fine particles. This fine powder was heat treated in the same manner as in Example 1 to obtain y-Fe203. Its magnetic properties are Hc of 29 e, os of Gisagimu/Yu, and bir of 3
It was 1 emu. A magnetic tape produced in the same manner as in Example 1 using this y-Fe203 as a magnetic material had an Hc of 2.
6 e, Bm is 1300 evening, Br is 100, Br/B
m was 0.77, and the degree of orientation was 2.3. Example 3 Currently widely used in practical use, the average length of the major axis is 0.5
Acicular Q-Fe00 day fine particles with a needle ratio of 731 were dispersed in 89 evening water and 800 ml of water.

これにＱ−Ｆｅ００日の量と生成されるｙ‐Ｆｅ００日
の量でモル比１：３となるように塩化第一鉄（ＦｅＣ１
２．４も○）１２００夕を水５ク中に溶解したものを加
え、かくはんを継続しながらさらにＮａＯＨ２４０夕を
水２２中に溶解したものを加えた。Ferrous chloride (FeC1
2.4 ○) 1,200 liters dissolved in 5 quarts of water was added, and while stirring was continued, 240 liters of NaOH dissolved in 22 quarts of water was added.

この反応溶液を２ぴ０の温度に保持して激しくかくはん
を続け、約４時間後溶液はオレンジ色に変化して反応を
完了したので生成沈でん物をろ別し水洗したのち乾燥．
粉砕してオレンジ色の微粉末を得た。これを電子顕微鏡
で観察したところ長軸の長さが平均０．６ｒ、針状比（
１０〜１５）：１の針状微粒子であった。この微粒子を
実施例１と同様に熱処理してｙータＦｅ２０３とした。This reaction solution was maintained at a temperature of 2.0 mm and continued to be stirred vigorously. After about 4 hours, the solution turned orange and the reaction was complete, so the precipitate formed was filtered out, washed with water, and then dried.
It was crushed to obtain an orange fine powder. When observed with an electron microscope, the length of the major axis was 0.6r on average, and the acicular ratio (
10-15):1 needle-like fine particles. These fine particles were heat-treated in the same manner as in Example 1 to obtain yetaFe203.

その磁気特性はＨｃが２８のｅｏｓが６段ｍｕノタ、。
ｒが３をｍｕ／夕であった。このｙ−Ｆｅ２０３を実施
例１と同様に磁性材料として作製した磁気テープはＨｃ
が２５のｅ、Ｂｍが１２５の、Ｂｒが１０５のＢｒ／Ｂ
ｍが０．８１、配向度が２．５であった。０ なおこの
は−Ｆｅ００日を原料として従来の方法で製造されたｙ
−Ｆｅ２０３の磁気特性はＨｃが、３８“史、りｓが７
父ｍｕ／夕、びｒが３７ｅｍｕ／夕であり、これを用い
て実施例１と全く同じように作製した磁気テープはＨｃ
が３４のｅ、Ｂｍが１３０に、タＢｒが９５の、Ｂｒ／
Ｂｍが０．７３、配向度が１．６であった。このように
本発明になる酸化物磁性材料の製造方法によると、磁気
テープ等に使用してすぐれた特性を有する酸化物磁性材
料を得ることができ０る。Its magnetic properties are Hc 28 and EOS 6-stage MU.
r was 3 mu/t. A magnetic tape made of this y-Fe203 as a magnetic material in the same manner as in Example 1 was
Br/B with e of 25, Bm of 125, and Br of 105
m was 0.81, and the degree of orientation was 2.5. 0 It should be noted that y produced by conventional methods using -Fe00 days as raw material
-The magnetic properties of Fe203 are: Hc is 38", and Ris is 7".
The magnetic tape produced in exactly the same manner as in Example 1 using the same mu/unit and bir was 37 emu/unit.
is 34 e, Bm is 130, Ta Br is 95, Br/
Bm was 0.73 and degree of orientation was 1.6. As described above, according to the method for producing an oxide magnetic material according to the present invention, it is possible to obtain an oxide magnetic material having excellent properties when used in magnetic tapes and the like.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図はＱ−Ｆｅ００日とッ−Ｆｅ００日のＸ線回折パ
ターン、第２図はＱ−Ｆｅ００日の電子顕微鏡写真、第
３図はその表面にｙ−Ｆｅ００日を生成させたものの電
子顕微鏡である。 第２図 第３図 第１図Figure 1 is an X-ray diffraction pattern of Q-Fe00 days and -Fe00 days, Figure 2 is an electron micrograph of Q-Fe00 days, and Figure 3 is an electron microscope photograph of the surface of which y-Fe00 days have been generated. It is. Figure 2 Figure 3 Figure 1

Claims (1)

【特許請求の範囲】[Claims] １ 針状α−ＦｅＯＯＨ微粒子の表面にγ−ＦｅＯＯＨ
を生成させ、該微粒子を加熱脱水した後還元、酸化して
γ−Ｆｅ＿２Ｏ＿３にする針状酸化物磁性材料の製造方
法。1 γ-FeOOH on the surface of acicular α-FeOOH fine particles
A method for producing an acicular oxide magnetic material by generating γ-Fe_2O_3 by heating and dehydrating the fine particles, and then reducing and oxidizing them to γ-Fe_2O_3.