JP2660714B2 - Method for producing cobalt-containing ferromagnetic iron oxide powder - Google Patents
Method for producing cobalt-containing ferromagnetic iron oxide powderInfo
- Publication number
- JP2660714B2 JP2660714B2 JP63061189A JP6118988A JP2660714B2 JP 2660714 B2 JP2660714 B2 JP 2660714B2 JP 63061189 A JP63061189 A JP 63061189A JP 6118988 A JP6118988 A JP 6118988A JP 2660714 B2 JP2660714 B2 JP 2660714B2
- Authority
- JP
- Japan
- Prior art keywords
- cobalt
- ferrous
- iron oxide
- oxide powder
- salt
- 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
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
- C09C1/22—Compounds of iron
- C09C1/24—Oxides of iron
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Compounds Of Iron (AREA)
- Hard Magnetic Materials (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は磁気記録媒体用材料として有用な優れた磁気
特性をもつコバルト含有強磁性酸化鉄粉末の製造方法に
関する。Description: TECHNICAL FIELD The present invention relates to a method for producing a cobalt-containing ferromagnetic iron oxide powder having excellent magnetic properties and useful as a material for a magnetic recording medium.
オーディオ、ビデオ、コンピューター、ワープロなど
の技術の進展にともない、これらの磁気記録媒体に使用
される記録材料について、より高品質のものが求められ
ている。コバルト含有強磁性酸化鉄粉末に関してもその
例外でない。その一環として保磁力、反転磁界分布、消
去特性、転写特性などに優れたものゝ研究開発が盛んに
おこなわれている。With the development of technologies such as audio, video, computers, and word processors, higher quality recording materials are required for these magnetic recording media. Cobalt-containing ferromagnetic iron oxide powder is no exception. As a part of this, those with excellent coercive force, switching magnetic field distribution, erasing characteristics, transfer characteristics, etc. are being actively researched and developed.
例えば、特開昭50−85612号(a)の技術は、γ−Fe2
O3粒子にコバルト化合物を被着させ、ついで第1鉄化合
物を被着させる変成処理方法に係り、その実施例では、
γ−Fe2O3粒子を分散させた水系スラリーに対し、コバ
ルト塩、アルカリ、および第1鉄塩をこの順に添加して
いる。この技術は保磁力と角形比の温度依存性、配向
性、転写特性などの改良を目的としている。つぎに特開
昭59−151402号(b)の技術は、磁性酸化鉄粉末にコバ
ルト化合物および第1鉄化合物を同時に被着させる変性
処理方法に係り、詳しくは、磁性酸化鉄粉末を分散させ
たアルカリ溶存水系スラリーに対し、コバルト塩および
第1鉄塩の水溶液を添加している。この技術は、保磁力
分布、消去特性、出力などの改良を目的としている。特
開昭59−107924号(c)の技術は、磁性酸化鉄粉末に第
1鉄化合物を被着させ、ついでコバルト化合物を被着さ
せる変成処理方法に係り、その実施例では、磁性酸化鉄
粉末を分散させたアルカリ溶存水系スラリーに対し、第
1鉄塩およびコバルト塩をこの順に添加している。この
技術は保磁力の経時安定性、角形比、配向性、反転磁界
分布などの改良を目的としている。また、特開昭61−17
426号(d)の技術は、γ−Fe2O3粒子に第1鉄化合物を
被着させ、ついでコバルト化合物を被着させる変成処理
方法に係り、詳しくは、γ−Fe2O3粒子を分散させたア
ルカリ溶存スラリーに対し、第1鉄塩を添加し一定の温
度条件下に所定時間撹拌したのちコバルト塩を添加して
いる。この技術は、保磁力、電磁変換特性などの改良を
目的としている。なお、特開昭51−23697号(e)に
は、強磁性酸化鉄粉末上にマグネタイト層を析出させた
後次いで該マグネタイト層の上にコバルト原子を含む強
磁性酸化鉄層を析出させる方法について記載しており、
その実施例では、鉄の水酸化物が析出している溶液中に
針状γ−Fe2O3粉末を添加した後酸化反応を行なわせて
該粉末上にマグネタイトを析出させ、次にこの粉末を鉄
とコバルトの水酸化物を沈澱させた溶液中に添加した後
酸化反応を行なわせている。For example, Japanese Patent Application Laid-Open No. 50-85612 (a) discloses a technique of γ-Fe 2
The present invention relates to a metamorphic treatment method in which a cobalt compound is deposited on O 3 particles and then a ferrous compound is deposited.
A cobalt salt, an alkali, and a ferrous salt are added in this order to an aqueous slurry in which γ-Fe 2 O 3 particles are dispersed. This technique aims at improving the temperature dependence of coercive force and squareness ratio, orientation, transfer characteristics, and the like. Next, the technique of JP-A-59-151402 (b) relates to a modification treatment method in which a cobalt compound and a ferrous compound are simultaneously applied to a magnetic iron oxide powder, and more specifically, a magnetic iron oxide powder is dispersed. An aqueous solution of a cobalt salt and a ferrous salt is added to the alkali-dissolved aqueous slurry. This technique aims at improving coercive force distribution, erasing characteristics, output, and the like. JP-A-59-107924 (c) relates to a metamorphic treatment method in which a ferrous compound is applied to a magnetic iron oxide powder and then a cobalt compound is applied. The ferrous salt and the cobalt salt are added in this order to the alkali-dissolved aqueous slurry in which is dispersed. This technique aims to improve the stability over time of the coercive force, the squareness ratio, the orientation, the switching magnetic field distribution, and the like. Also, JP-A-61-17
Technology 426 No. (d) is allowed to deposited ferrous compound γ-Fe 2 O 3 particles, then it relates to a modified processing method of depositing cobalt compound, specifically, a γ-Fe 2 O 3 particles The ferrous salt is added to the dispersed alkali-dissolved slurry, and the mixture is stirred for a predetermined time under a constant temperature condition, and then the cobalt salt is added. This technique aims at improving coercive force, electromagnetic conversion characteristics, and the like. JP-A-51-23697 (e) discloses a method of depositing a magnetite layer on a ferromagnetic iron oxide powder and then depositing a ferromagnetic iron oxide layer containing cobalt atoms on the magnetite layer. Has been described,
In the example, the needle-like γ-Fe 2 O 3 powder was added to the solution in which the hydroxide of iron was precipitated, and then an oxidation reaction was performed to precipitate magnetite on the powder. Is added to a solution in which a hydroxide of iron and cobalt is precipitated, and then an oxidation reaction is carried out.
前記従来技術の関係は、(a)及び(b)の方法に対
し、その反転磁界分布および消去特性を改善しようとす
るのが、(c)および(d)の方法であるとして捉えら
れる。しかし、(c)および(d)の方法においても未
だその程度が十分でなく、とくに磁性酸化鉄粉末が例え
ば比表面積50m2/gのような微粒子の場合や保磁力が700O
e以上の高保磁力粉末の場合に一層の改良が望まれてい
る。また、(e)の方法では、高保磁力のものが得られ
難いという欠陥がある。The relationship of the prior art is considered to be that the methods (c) and (d) attempt to improve the switching field distribution and the erasing characteristics with respect to the methods (a) and (b). However, even in the methods (c) and (d), the degree is still insufficient, especially when the magnetic iron oxide powder is fine particles having a specific surface area of, for example, 50 m 2 / g, or when the coercive force is 700O.
Further improvement is desired for high coercivity powders of e or higher. Further, the method (e) has a defect that it is difficult to obtain a material having a high coercive force.
本発明者等は従来の変性被着技術の中で特に前記
(b)に記載されている、磁性酸化鉄粉末を分散させた
アルカリ溶存水系スラリー中に第1鉄塩およびコバルト
塩の水溶液を添加する方法について種々検討した結果、
磁性酸化鉄粉末のアルカリ溶存水系スラリー中への第1
鉄塩およびコバルト塩の水溶液の添加を離隔的に、いわ
ゆる並列添加することにより反転磁界分布および消去特
性、転写特性に優れたものが得られることを見出して特
許出願をした。(特願昭63−25199号)その後、更に検
討した結果、(イ)並列添加する前に、第1鉄塩の一部
を予め被着処理すること及び(ロ)この被着処理を磁性
酸化鉄粉末の第1鉄塩溶存水系スラリー中にアルカリを
添加して反応させる方法を採用することにより、意外に
も反転磁界分布および消去特性、転写特性が著しく改善
されることを見出して本発明方法を完成したものであ
る。The present inventors added an aqueous solution of a ferrous salt and a cobalt salt to an alkali-dissolved aqueous slurry in which a magnetic iron oxide powder is dispersed, which is described in (b) above among the conventional modified deposition techniques. As a result of various studies on how to
No. 1 in magnetic iron oxide powder in alkali-dissolved aqueous slurry
The applicant has filed a patent application by finding out that the addition of an aqueous solution of an iron salt and a cobalt salt at a distance, that is, so-called parallel addition, results in excellent switching field distribution, erasing characteristics, and transfer characteristics. (Japanese Patent Application No. 63-25199) After further investigation, it was found that (a) a part of the ferrous salt was preliminarily coated before the parallel addition, and (b) this coating was magnetically oxidized. It has been found that by employing a method in which an alkali is added to a ferrous salt-dissolved aqueous slurry of iron powder to cause a reaction, surprisingly, the switching field distribution, the erasing characteristics and the transfer characteristics are remarkably improved. Is completed.
すなわち本発明は、磁性酸化鉄粉末を第1鉄化合物と
コバルト化合物とにより変性被着処理する方法におい
て、まず前段として、磁性酸化鉄粉末の第1鉄塩溶存水
系スラリー中にアルカリを添加して第1鉄化合物を被着
し、後段として、前段で得られたスラリー中にアルカリ
を存在させ、該アルカリと第1鉄塩およびコバルト塩と
を離隔的に同時に反応させ第1鉄化合物およびコバルト
化合物を被着するこを特徴とするコバルト含有強磁性酸
化鉄粉末の製造方法である。That is, the present invention relates to a method of modifying and applying a magnetic iron oxide powder with a ferrous compound and a cobalt compound. In the first step, alkali is added to a ferrous iron salt-dissolved aqueous slurry of the magnetic iron oxide powder as a first step. A ferrous compound is applied, and, as a latter stage, an alkali is present in the slurry obtained in the former stage, and the alkali and the ferrous salt and the cobalt salt are simultaneously and separately reacted to form a ferrous compound and a cobalt compound. And a method for producing a cobalt-containing ferromagnetic iron oxide powder.
磁性酸化鉄粉末に第1鉄化合物およびコバルト化合物
を被着して変性処理する本発明においては、まず前段と
して、磁性酸化鉄粉末の水系媒液に第1鉄塩水溶液を加
えて得られる第1鉄塩溶存水系スラリーにアルカリを添
加して該スラリー中の第1鉄塩を中和し、第1鉄化合物
を被着させる。その後引続き後段として、前段で得られ
た中和水系スラリーにアルカリを存在させ、該アルカリ
と第1鉄塩およびコバルト塩とを離隔的に同時に反応さ
せ、第1鉄化合物およびコバルト化合物を被着させる。In the present invention, in which a ferrous compound and a cobalt compound are applied to a magnetic iron oxide powder for denaturation treatment, first, as a first step, a first iron salt aqueous solution obtained by adding a ferrous salt aqueous solution to an aqueous medium of the magnetic iron oxide powder is used. An alkali is added to the iron-salt-dissolved aqueous slurry to neutralize the ferrous salt in the slurry and deposit a ferrous compound. Thereafter, as a subsequent stage, an alkali is present in the neutralized aqueous slurry obtained in the preceding stage, and the alkali and the ferrous salt and the cobalt salt are simultaneously and separately reacted to deposit the ferrous compound and the cobalt compound. .
本発明で用いる磁性酸化鉄粉末としては、γ−Fe
2O3、γ−Fe2O3を部分還元して得られるベルトライド、
Fe3O4などの針状磁性酸化鉄粉末が挙げられ、中でもγ
−Fe2O3が好ましい。水系媒液としては、一般に工業用
水、純水(イオン交換樹脂処理)などが用いられる。な
お、これらは予め不活性ガス(例えば窒素ガス)でバブ
リングしてその酸化作用を抑制したものを用いるのが望
ましい。また適当な分散剤、緩衝塩類などを添加するこ
とができる。第1鉄塩としては、例えば硫酸第1鉄、硝
酸第1鉄、塩化第1鉄などの鉱酸の第1鉄塩が挙げら
れ、工業的には硫酸第1鉄が好ましく、一般に0.1〜1.5
モル/l程度の濃度の水溶液として加える。As the magnetic iron oxide powder used in the present invention, γ-Fe
2 O 3, obtained by partial reduction of the γ-Fe 2 O 3 berthollides,
Needle-like magnetic iron oxide powder such as Fe 3 O 4
-Fe 2 O 3 is preferable. As the aqueous medium, industrial water, pure water (ion exchange resin treatment) or the like is generally used. Note that it is preferable to use those in which the oxidizing action is suppressed by bubbling with an inert gas (for example, nitrogen gas) in advance. Also, suitable dispersants, buffer salts and the like can be added. Examples of the ferrous salt include ferrous salts of mineral acids such as ferrous sulfate, ferrous nitrate, and ferrous chloride. Ferrous sulfate is industrially preferable, and generally 0.1 to 1.5.
Add as an aqueous solution with a concentration of about mol / l.
前段の被着処理において、磁性酸化鉄粉末の水系媒液
中の該磁性酸化鉄粉末の濃度(含有量)は、通常、20〜
200g/l、望ましくは50〜150g/lであり、比表面積が大き
い微粉末を用いるときは薄い濃度に設定するのが好まし
い。磁性酸化鉄粉末の水系媒液への分散は、普通、機械
的撹拌でおこなうが、その他の手段、例えば超音波を利
用することができる。溶存させる第1鉄塩の量は、被着
量が前記磁性酸化鉄粉末の全Fe量に対し、Feとして0.5
〜25重量%、望ましくは1〜15重量%になるようにす
る。この範囲より多すぎても、また逆に少なすぎても反
転磁界分布、消去特性や転写特性が改善されず、また保
磁力の向上が十分でないなどの問題を招き好ましくな
い。In the first deposition step, the concentration (content) of the magnetic iron oxide powder in the aqueous medium of the magnetic iron oxide powder is usually 20 to
It is 200 g / l, desirably 50 to 150 g / l, and when a fine powder having a large specific surface area is used, it is preferable to set the concentration to a low concentration. The dispersion of the magnetic iron oxide powder in the aqueous medium is usually performed by mechanical stirring, but other means such as ultrasonic waves can be used. The amount of the ferrous salt to be dissolved is such that the amount of the deposited iron is 0.5
-25% by weight, preferably 1-15% by weight. If the ratio is too large or too small, the switching field distribution, the erasing characteristics and the transfer characteristics are not improved, and the coercive force is not sufficiently improved.
本発明で用いる中和剤としてのアルカリは、アルカリ
金属またはアルカリ土類金属の水酸化物、酸化物あるい
は炭酸塩などが用いられ、例えば水酸化ナトリウム、水
酸化カリウム、酸化ナトリウム、炭酸カルシウムなどが
挙げられ、工業的には水酸化ナトリウム、水酸化カリウ
ムなどが好ましい。本発明において、アルカリは、前段
での第1鉄塩の中和当量及び後段での第1鉄塩とコバル
ト塩との中和当量の総量以上を前段で添加しておくのが
望ましいが、前段の中和反応終了後に後段で必要なアル
カリを添加してもよい。As the alkali used as the neutralizing agent used in the present invention, hydroxides, oxides or carbonates of alkali metals or alkaline earth metals are used, for example, sodium hydroxide, potassium hydroxide, sodium oxide, calcium carbonate and the like. Industrially, sodium hydroxide and potassium hydroxide are preferred. In the present invention, it is desirable to add at least the total amount of the neutralization equivalent of the ferrous salt in the former stage and the neutralization equivalent of the ferrous salt and the cobalt salt in the latter stage in the former stage. After completion of the neutralization reaction, a necessary alkali may be added at a later stage.
前段の被着処理は、普通、第1鉄化合物が実質的に酸
化されないような非酸化性雰囲気で、50℃以下、望まし
くは10〜30℃で行なう。この範囲より温度が高くなりす
ぎると保磁力の上昇が不十分となり、また、工業的に10
℃以下とする為には冷凍機などの設置が必要となって好
ましくない。The pre-deposition treatment is usually performed in a non-oxidizing atmosphere such that the ferrous compound is not substantially oxidized at 50 ° C. or lower, preferably 10 to 30 ° C. If the temperature is too high, the coercive force will not rise sufficiently, and industrially,
In order to lower the temperature to below ℃, it is necessary to install a refrigerator or the like, which is not preferable.
後段の被着処理は、前段で得られた中和水系スラリー
にアルカリを存在させ、該アルカリと第1鉄塩およびコ
バルト塩とを離隔的に同時に反応させ第1鉄化合物およ
びコバルト化合物を被着させる。「離隔的に同時に」と
は、第1鉄塩およびコバルト塩のそれぞれがアルカリと
反応する前に第1鉄塩とコバルト塩とが混合状態でアル
カリと直接反応することを回避し、またそれぞれの反応
は、少なくともある時期に重なる時間があることを意味
する。この条件は、例えばアルカリ性スラリーへの第1
鉄塩およびコバルト塩の添加を別箇に並列的におこなう
ことで達成される。通常、第1鉄塩水溶液とコバルト塩
水溶液とを別々の供給管から前記スラリーに一定時間を
かけて添加する。この場合、添加が実質的に同時に、開
始し終了するように(並列添加被着処理)しても、また
部分的同時期になるように重ね合わせ(部分的重ね合わ
せ被着処理)してもよい。第1鉄塩溶液とコバルト塩溶
液とを混合して添加したり、第1鉄塩溶液の添加終了後
にコバルト塩を添加したりするような方法では、本発明
の所望の効果が得られ難い。In the subsequent deposition treatment, an alkali is present in the neutralized aqueous slurry obtained in the preceding stage, and the alkali and the ferrous salt and the cobalt salt are simultaneously and separately reacted to deposit the ferrous compound and the cobalt compound. Let it. “Separately simultaneously” means that the ferrous salt and the cobalt salt do not directly react with the alkali in a mixed state before each of the ferrous salt and the cobalt salt react with the alkali, and A reaction means that there is at least some overlapping time. This condition is, for example, the first to the alkaline slurry.
This is achieved by adding iron salts and cobalt salts separately and in parallel. Usually, a ferrous salt aqueous solution and a cobalt salt aqueous solution are added to the slurry from separate supply pipes over a certain period of time. In this case, the addition may be started and finished at substantially the same time (parallel addition deposition process), or may be superimposed so as to be partially simultaneous (partial superposition deposition process). Good. In a method in which a ferrous salt solution and a cobalt salt solution are mixed and added, or a cobalt salt is added after completion of the addition of the ferrous salt solution, it is difficult to obtain the desired effects of the present invention.
後段の被着処理における第1鉄塩およびコバルト塩の
添加所要時間は、一概にはいえないが、一般に10分〜5
時間、望ましくは20分〜3時間、さらに望ましくは30分
〜2時間である。この添加は、普通、撹拌下に系内の温
度が50℃以下、望ましくは30℃をあまり上回らない温度
で例えば35℃以下、特に望ましくは30℃以下で行なう。
添加完了後、一般に3時間以上望ましくは5から20時
間、撹拌下に一定の温度範囲に維持し、熟成することに
より被着処理が完結する。熟成は通常50℃をあまり上回
らない温度で例えば60℃以下、好ましくは50℃以下で行
なうのがよい。The time required for adding the ferrous salt and the cobalt salt in the subsequent deposition process cannot be generally specified, but generally ranges from 10 minutes to 5 minutes.
Time, preferably 20 minutes to 3 hours, more preferably 30 minutes to 2 hours. This addition is usually carried out with stirring at a temperature in the system below 50 ° C., preferably below 30 ° C., for example below 35 ° C., particularly preferably below 30 ° C.
After completion of the addition, the temperature is maintained at a constant temperature range under stirring for generally 3 hours or more, preferably 5 to 20 hours, and the coating is completed by aging. Aging is usually performed at a temperature not much higher than 50 ° C., for example, at 60 ° C. or less, preferably at 50 ° C. or less.
後段の被着処理時の雰囲気は、前段と同様に非酸化性
である。もっとも所望の磁気特性のものを得るため、第
1鉄化合物をある程度酸化するように雰囲気を調整する
場合もある。The atmosphere during the subsequent deposition process is non-oxidizing as in the previous stage. In order to obtain desired magnetic properties, the atmosphere may be adjusted so that the ferrous compound is oxidized to some extent.
後段で用いる第1鉄塩は、前段と同じものが好まし
く、コバルト塩は、硫酸コバルト、塩化コバルト、酢酸
コバルトなどであり、工業的には硫酸コバルトが好まし
い。これらの第1鉄塩およびコバルト塩は、通常、それ
ぞれの水溶液として用い、その濃度は工業的には、第1
鉄塩は0.1〜1.5モル/l、コバルト塩は0.2〜2.0モル/l程
度が奨められる。The ferrous salt used in the latter stage is preferably the same as that in the former stage, and the cobalt salt is, for example, cobalt sulfate, cobalt chloride or cobalt acetate, and industrially, cobalt sulfate is preferred. These ferrous salts and cobalt salts are usually used as respective aqueous solutions, and their concentrations are industrially the first ferrous salts and cobalt salts.
About 0.1 to 1.5 mol / l of iron salt and about 0.2 to 2.0 mol / l of cobalt salt are recommended.
後段における被着処理後のスラリー中のOH基濃度(中
和当量以上の遊離OH基濃度)は、通常0.01〜3モル/lで
あり、望ましくは0.5〜2モル/lである。したがって、
後段でのアルカリの添加量は、この条件に基いて第1鉄
塩およびコバルト塩の種類、添加量などから設定され
る。The OH group concentration (free OH group concentration equal to or higher than the neutralization equivalent) in the slurry after the application treatment in the latter stage is usually 0.01 to 3 mol / l, preferably 0.5 to 2 mol / l. Therefore,
The amount of alkali added in the latter stage is set based on the types and amounts of ferrous salt and cobalt salt based on these conditions.
後段における第1鉄塩およびコバルト塩の被着量は、
前記磁性酸化鉄粉末の全Fe量に対し、前者はFeとして1
〜30重量%、望ましくは2〜20重量%であり、後者はCo
として0.1〜20重量%、望ましくは0.5〜15重量%であ
る。第1鉄の添加量は少なすぎると、保磁力や飽和磁化
量の上昇が望めず、得られる磁性粉末の電気抵抗が高く
なるなどの問題を招いて好ましくない。また逆に多すぎ
ると比表面積の低下を招いたり、保磁力や消去特性など
の経時変化が悪化するなどの問題を招き易くなるために
好ましくない。コバルト塩の添加量が少なすぎると保磁
力の上昇が望めず、逆に多すぎると保磁力分布や分散性
の悪化を招き易くなるため好ましくない。The amount of ferrous salt and cobalt salt deposited in the latter stage is
For the total Fe content of the magnetic iron oxide powder, the former is 1 as Fe.
-30% by weight, preferably 2-20% by weight, the latter being Co
0.1 to 20% by weight, desirably 0.5 to 15% by weight. If the amount of ferrous iron is too small, the coercive force and the saturation magnetization cannot be increased, which is not preferable because it causes problems such as an increase in electric resistance of the obtained magnetic powder. Conversely, if the content is too large, it is not preferable because problems such as a decrease in specific surface area and deterioration of the coercive force and erasing characteristics over time are easily caused. If the addition amount of the cobalt salt is too small, an increase in the coercive force cannot be expected, and if it is too large, the coercive force distribution and the dispersibility tend to be deteriorated, which is not preferable.
変性被着処理後、通常、脱水し水洗してアルカリを除
去し、ついで乾燥する。After the modified deposition treatment, the product is usually dehydrated and washed with water to remove alkalis, and then dried.
乾燥は、窒素などの不活性雰囲気であっても、空気ま
たは空気と不活性ガスとの混合ガスの雰囲気であっても
よい。非酸化性雰囲気で乾燥して得られるものは、酸化
性雰囲気の場合のそれに比較して、おゝむね保磁力発現
に優れるようである。乾燥温度は、工業的に用いられる
通常の温度でよく、一般に60〜150℃程度を用いること
が多い。Drying may be performed in an inert atmosphere such as nitrogen, or in an atmosphere of air or a mixed gas of air and an inert gas. Those obtained by drying in a non-oxidizing atmosphere seem to be generally superior in coercive force development as compared with those in an oxidizing atmosphere. The drying temperature may be a normal temperature used industrially, and generally about 60 to 150 ° C. is often used.
このようにして所望の特性を有するコバルト含有強磁
性酸化鉄粉末が得られるが、このものは、さらに100〜2
00℃の温度で乾式熱処理をおこなうことにより、保磁力
やその他の磁気特性が改善される場合がある。In this way, a cobalt-containing ferromagnetic iron oxide powder having the desired properties is obtained, which is further reduced by 100 to 2
By performing the dry heat treatment at a temperature of 00 ° C., the coercive force and other magnetic properties may be improved in some cases.
なお、前記の変成被着処理を施して得られるコバルト
含有強磁性酸化鉄粉末に対し、特開昭63−10375号明細
書に記載した方法に基き、ケイ素、アルミニウム、カル
シウム、チタン、バナジウム、ニッケル、亜鉛、リンな
どの化合物を表面に被覆させて、前記強磁性酸化鉄粉末
の有する優れた磁気特性の外に、望ましい経時安定性
(△Hc)および脂肪酸吸着特性(C14吸着量)を兼ね備
えたものを製造することができる。The cobalt-containing ferromagnetic iron oxide powder obtained by performing the above-mentioned metamorphic deposition treatment was subjected to silicon, aluminum, calcium, titanium, vanadium, nickel and nickel based on the method described in JP-A-63-10375. zinc, by coating the compound on a surface, such as phosphorus, wherein the outside of excellent magnetic properties having a ferromagnetic iron oxide powder, both the desired stability over time (△ Hc) and fatty acid adsorption properties (C 14 adsorption) Can be manufactured.
実施例1 γ−Fe2O3粉末(保磁力310Oe、平均長軸粒子径0.12μ
m、軸比約6)100gを水1に分散させたスラリーを20
℃の温度に保持しながら、窒素ガス雰囲気下に0.90モル
/lの硫酸第1鉄水溶液105mlを加え、第1鉄塩溶存スラ
リーとした。次に、該スラリーに10モル/lの水酸化ナト
リウム水溶液201mlを添加して、γ−Fe2O3粉末表面に第
1鉄化合物を被着した。引続き、このスラリー中に0.90
モル/lの硫酸第1鉄水溶液105ml及び0.85モル/lの硫酸
コバルト水溶液84mlを並列添加して第1鉄化合物及びコ
バルト化合物を被着した。この並列添加は、両水溶液が
約60分でそれぞれ供給されるように供給速度を調節した
小型ポンプ、供給管(内径約2.5mm、両供給管の間隔約1
5cm)を用いて、同時に添加を開始、終了するように行
なった。添加終了後、1時間撹拌、熟成し、35℃に昇温
して更に4時間撹拌、熟成した。その後、濾過、水洗
し、窒素ガス雰囲気中120℃で乾燥して、目的のコバル
ト含有強磁性酸化鉄粉末(A)を得た。Example 1 γ-Fe 2 O 3 powder (coercive force 310 Oe, average major axis particle size 0.12 μm
m, axial ratio about 6) A slurry of 100 g dispersed in water 1
0.90 mol under a nitrogen gas atmosphere while maintaining the temperature
105 ml of a 1 / l aqueous solution of ferrous sulfate was added to obtain a ferrous salt-dissolved slurry. Next, 201 ml of a 10 mol / l aqueous solution of sodium hydroxide was added to the slurry to deposit a ferrous compound on the surface of the γ-Fe 2 O 3 powder. Subsequently, 0.90
The ferrous compound and the cobalt compound were deposited by adding 105 ml of an aqueous solution of ferrous sulfate (mol / l) and 84 ml of an aqueous solution of 0.85 mol / l cobalt sulfate in parallel. This parallel addition is performed by a small pump with a controlled supply rate so that both aqueous solutions are supplied in about 60 minutes, a supply pipe (inner diameter: about 2.5 mm, a distance between both supply pipes of about 1
5 cm) so as to simultaneously start and end the addition. After completion of the addition, the mixture was stirred and aged for 1 hour, heated to 35 ° C., and further stirred and aged for 4 hours. Thereafter, the resultant was filtered, washed with water, and dried at 120 ° C. in a nitrogen gas atmosphere to obtain the desired cobalt-containing ferromagnetic iron oxide powder (A).
実施例2 実施例1において、前段で添加する硫酸第1鉄水溶液
の量を42mlとすること及び後段の硫酸第1鉄水溶液の添
加量を168mlとすること以外は同様に処理して、目的の
コバルト含有強磁性酸化鉄粉末(B)を得た。Example 2 The same procedure as in Example 1 was carried out except that the amount of the aqueous ferrous sulfate solution added in the former stage was changed to 42 ml and the amount of the aqueous ferrous sulfate solution added in the latter stage was changed to 168 ml. A cobalt-containing ferromagnetic iron oxide powder (B) was obtained.
実施例3 実施例1において、前段で添加する硫酸第1鉄水溶液
の量を168mlとすること及び後段の硫酸第1鉄水溶液の
添加量を42mlとすること以外は同様に処理して、目的の
コバルト含有強磁性酸化鉄粉末(C)を得た。Example 3 The same procedure as in Example 1 was carried out except that the amount of the aqueous ferrous sulfate solution added in the former stage was 168 ml and the amount of the aqueous ferrous sulfate solution added in the latter stage was 42 ml, and the desired A cobalt-containing ferromagnetic iron oxide powder (C) was obtained.
比較例1 実施例1で用いたものと同じγ−Fe2O3粉末100gを水
1と10モル/lの水酸化ナトリウム水溶液201mlの混合
溶液に分散させてスラリーとし、このスラリーを20℃の
温度に保持しながら、窒素ガス雰囲気下に0.90モル/lの
硫酸第1鉄水溶液210mlと0.85mol/lの硫酸コバルト水溶
液84mlとの混合水溶液294mlを約60分間で添加して第1
鉄化合物とコバルト化合物とを被着した。その後実施例
1と同様に熟成、濾過、水洗、乾燥してコバルト含有強
磁性酸化鉄粉末(D)を得た。Comparative Example 1 100 g of the same γ-Fe 2 O 3 powder as used in Example 1 was dispersed in a mixed solution of water 1 and 201 ml of a 10 mol / l sodium hydroxide aqueous solution to form a slurry. While maintaining the temperature, 294 ml of a mixed aqueous solution of 210 ml of a 0.90 mol / l ferrous sulfate aqueous solution and 84 ml of a 0.85 mol / l aqueous cobalt sulfate solution was added in about 60 minutes under a nitrogen gas atmosphere, and the first solution was added.
An iron compound and a cobalt compound were deposited. Thereafter, aging, filtration, washing with water and drying were performed in the same manner as in Example 1 to obtain a cobalt-containing ferromagnetic iron oxide powder (D).
比較例2 比較例1における硫酸第1鉄水溶液と硫酸コバルト水
溶液の混合水溶液による添加を、実施例1で採用の並列
添加に代える以外は比較例1の場合と同様に処理してコ
バルト含有強磁性酸化鉄粉末(E)を得た。Comparative Example 2 A cobalt-containing ferromagnetic substance was treated in the same manner as in Comparative Example 1 except that the addition of the mixed aqueous solution of the ferrous sulfate aqueous solution and the cobalt sulfate aqueous solution in Comparative Example 1 was replaced with the parallel addition employed in Example 1. An iron oxide powder (E) was obtained.
比較例3 実施例1において、後段の並列添加被着処理に代え
て、比較例1と同様に硫酸第1鉄と硫酸コバルトの混合
水溶液として加える混合添加被着処理とすること以外は
実施例1の場合と同様に処理してコバルト含有強磁性酸
化鉄粉末(F)を得た。Comparative Example 3 Example 1 was repeated except that, instead of the parallel addition deposition treatment in the subsequent stage, a mixed addition deposition treatment was performed in which a mixed aqueous solution of ferrous sulfate and cobalt sulfate was added as in Comparative Example 1. In the same manner as in the above, a cobalt-containing ferromagnetic iron oxide powder (F) was obtained.
実施例4 実施例1において、後段の被着処理を、まず、硫酸第
1鉄水溶液の添加を約45分間で完了するように行ない、
その添加開始後15分経過した時点で硫酸コバルト水溶液
の添加を約60分間で完了するように行なう処理に代える
こと以外は同様に処理して目的のコバルト含有強磁性酸
化鉄粉末(G)を得た。Example 4 In Example 1, the subsequent deposition treatment was performed such that the addition of the aqueous ferrous sulfate solution was completed in about 45 minutes.
15 minutes after the start of the addition, the same treatment was carried out except that the addition of the aqueous solution of cobalt sulfate was completed in about 60 minutes to obtain the desired cobalt-containing ferromagnetic iron oxide powder (G). Was.
比較例4 実施例1で用いたものと同じγ−Fe2O3粉末100gを水
1に分散させたスラリーを20℃の温度に保持しなが
ら、窒素ガス雰囲気下に0.90モル/lの硫酸第1鉄水溶液
210mlを加え、第1鉄塩溶存スラリーとした。次に、該
スラリーに10モル/lの水酸化ナトリウム水溶液201mlを
添加して、γ−Fe2O3粉末表面に第1鉄化合物を被着し
た。引続き、このスラリーに0.85モル/lの硫酸コバルト
水溶液84mlを添加してコバルト化合物を被着した。その
後、実施例1と同様に熟成、濾過、水洗、乾燥してコバ
ルト含有強磁性酸化鉄粉末(H)を得た。Comparative Example 4 0.90 mol / l of sulfuric acid sulfuric acid was added under a nitrogen gas atmosphere while maintaining a slurry in which 100 g of the same γ-Fe 2 O 3 powder as used in Example 1 was dispersed in water 1 at a temperature of 20 ° C. 1 iron aqueous solution
210 ml was added to obtain a ferrous salt dissolved slurry. Next, 201 ml of a 10 mol / l aqueous solution of sodium hydroxide was added to the slurry to deposit a ferrous compound on the surface of the γ-Fe 2 O 3 powder. Subsequently, 84 ml of a 0.85 mol / l aqueous solution of cobalt sulfate was added to the slurry to deposit a cobalt compound. Thereafter, aging, filtration, washing with water and drying were performed in the same manner as in Example 1 to obtain a cobalt-containing ferromagnetic iron oxide powder (H).
比較例5 実施例1で用いたものと同じγ−Fe2O3粉末100gを水
1と10モル/lの水酸化ナトリウム水溶液201mlの混合
溶液に分散させたスラリーを20℃に保持しながら窒素ガ
ス雰囲気下に0.90モル/lの硫酸第1鉄水溶液210mlの添
加を約45分間で完了するように行ない、その添加開始後
15分経過した時点で0.85モル/lの硫酸コバルト水溶液84
mlの添加を約60分間で完了するように行なって第1鉄化
合物及びコバルト化合物を被着した。その後は実施例1
と同様に熟成、濾過、水洗、乾燥してコバルト含有強磁
性酸化鉄(I)を得た。Comparative Example 5 A slurry obtained by dispersing 100 g of the same γ-Fe 2 O 3 powder as that used in Example 1 in a mixed solution of water 1 and 201 ml of a 10 mol / l aqueous sodium hydroxide solution while maintaining the temperature at 20 ° C. with nitrogen In a gas atmosphere, the addition of 210 ml of a 0.90 mol / l ferrous sulfate aqueous solution was performed in about 45 minutes to complete the addition.
After 15 minutes, 0.85 mol / l cobalt sulfate aqueous solution 84
The addition of the ml was made to complete in about 60 minutes to deposit the ferrous and cobalt compounds. After that, Example 1
In the same manner as in the above, aging, filtration, washing with water and drying were performed to obtain a cobalt-containing ferromagnetic iron oxide (I).
上記サンプルA〜Iについて、通常の方法により保磁
力(Hc)を測定し、その結果を第1表に示す。For the samples A to I, the coercive force (Hc) was measured by an ordinary method, and the results are shown in Table 1.
さらにサンプルA〜Iについて、下記の配合割合に従
って配合物を調製し、ボールミルで混練して磁性塗料を
製造した。Further, for Samples A to I, a blend was prepared according to the following blend ratio, and kneaded with a ball mill to produce a magnetic paint.
(1)コバルト含有強磁性酸化鉄粉末 100.0重量% (2)添加剤 3.8 〃 (3)塩ビ−酢ビ共重合体 8.0 〃 (4)ポリウレタン樹脂 35.5 〃 (5)混合溶剤(トルエン/MEK=1/1) 216.2 〃 (6)シクロヘキサノン 36.0 〃 ついで各々の磁性塗料をポリエステルフィルムに通常
の方法により塗布、配向した後、乾燥して約9μの磁性
塗膜を有する磁気テープを作製した。それぞれのテープ
について、通常の方法により、保磁力(Hc)、角形比
(Br/Bm)、配向性(OR)、反転磁界分布(SFD)、消去
特性(dB)および転写特性(dB)を測定した結果を第1
表に示す。(1) Cobalt-containing ferromagnetic iron oxide powder 100.0% by weight (2) Additive 3.8 〃 (3) PVC-vinyl acetate copolymer 8.0 〃 (4) Polyurethane resin 35.5 〃 (5) Mixed solvent (toluene / MEK = 1 / 1) 216.2 {(6) Cyclohexanone 36.0} Then, each magnetic paint was applied to a polyester film by a usual method, oriented, and dried to prepare a magnetic tape having a magnetic coating of about 9 μm. For each tape, measure coercive force (Hc), squareness ratio (Br / Bm), orientation (OR), switching field distribution (SFD), erasing characteristics (dB) and transfer characteristics (dB) by the usual method The result of the first
It is shown in the table.
〔発明の効果〕 第1表から明らかなように、本発明方法によって得ら
れるコバルト含有強磁性酸化鉄は、優れた磁気特性を有
するものであり、従来法によって得られる磁性酸化鉄と
比較しても、とくに反転磁界分布および消去特性、転写
特性に一段と優れたものである。 [Effects of the invention] As is clear from Table 1, the cobalt-containing ferromagnetic iron oxide obtained by the method of the present invention has excellent magnetic properties, and is compared with the magnetic iron oxide obtained by the conventional method. In particular, they are much more excellent in the switching magnetic field distribution, the erasing characteristics, and the transfer characteristics.
Claims (2)
化合物とにより変性被着処理する方法において、まず前
段として、磁性酸化鉄粉末の第1鉄塩溶存水系スラリー
中にアルカリを添加して第1鉄化合物を被着し、後段と
して、前段で得られたスラリー中にアルカリを存在さ
せ、該スラリー中に第1鉄塩およびコバルト塩を別個に
並列的に添加して反応させ第1鉄化合物およびコバルト
化合物を被着することを特徴とするコバルト含有強磁性
酸化鉄粉末の製造方法。In a method for modifying a magnetic iron oxide powder with a ferrous compound and a cobalt compound, an alkali is added to a ferrous salt-dissolved aqueous slurry of the magnetic iron oxide powder as a first step. A ferrous compound is deposited, and, as a subsequent step, an alkali is present in the slurry obtained in the preceding step, and a ferrous salt and a cobalt salt are separately added in parallel to the slurry to cause a reaction. A method for producing a cobalt-containing ferromagnetic iron oxide powder, comprising applying a compound and a cobalt compound.
気下でおこなう請求項1記載の製造方法。2. The method according to claim 1, wherein the first and second deposition processes are performed in a non-oxidizing atmosphere.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63061189A JP2660714B2 (en) | 1988-03-15 | 1988-03-15 | Method for producing cobalt-containing ferromagnetic iron oxide powder |
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Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63061189A JP2660714B2 (en) | 1988-03-15 | 1988-03-15 | Method for producing cobalt-containing ferromagnetic iron oxide powder |
Publications (2)
Publication Number | Publication Date |
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JPH01234333A JPH01234333A (en) | 1989-09-19 |
JP2660714B2 true JP2660714B2 (en) | 1997-10-08 |
Family
ID=13163969
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JPS5850005A (en) * | 1981-08-31 | 1983-03-24 | Fanuc Ltd | Instructing method |
JPS59107924A (en) * | 1982-12-08 | 1984-06-22 | Ishihara Sangyo Kaisha Ltd | Manufacture of magnetic iron oxide powder containing cobalt |
JPS6117426A (en) * | 1984-07-04 | 1986-01-25 | Sony Corp | Preparation of magnetic power of cobalt-containing iron oxide |
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