JPH034489B2 - - Google Patents
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- Publication number
- JPH034489B2 JPH034489B2 JP57045197A JP4519782A JPH034489B2 JP H034489 B2 JPH034489 B2 JP H034489B2 JP 57045197 A JP57045197 A JP 57045197A JP 4519782 A JP4519782 A JP 4519782A JP H034489 B2 JPH034489 B2 JP H034489B2
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- magnetic powder
- magnetic
- particles
- suspension
- mol
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- Hard Magnetic Materials (AREA)
Description
【発明の詳細な説明】
この発明は、磁性粉末の製法に関するもであ
り、更に詳細には、特に所謂Co披着型磁性粉末
の製法に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing magnetic powder, and more particularly to a method for producing so-called Co-deposited magnetic powder.
従来、高抵磁力の磁性粉末として、磁性酸化鉄
粒子内にコバルトイオンを固溶（ドープ）させた
ものが知られている。しかしHcが上昇する原因
は、結晶磁気異方性であるため、温度異存性が大
きく、かかる磁性粉末に特にテープにした場合に
転写特性が悪いという欠点があつた。 Conventionally, as a magnetic powder with high magnetic resistance, one in which cobalt ions are dissolved (doped) in magnetic iron oxide particles is known. However, since the increase in Hc is due to magnetocrystalline anisotropy, there is a large temperature anisotropy, and such magnetic powders have the drawback of poor transfer characteristics, especially when used in tapes.
したがつて、最近では、コバルトイオンをγ−
Fe2O3粒子内に拡散させず、その粒子表面にコバ
ルト化合物として存在させることによりHcを上
昇させる方法によつて、Co被着型磁性粉末を得
ることが実用化させるに至つている。しかし、か
かるCo被着柄磁性粉末も、製造段階の差異、生
成後の熱処理などによつて、表面状態は勿論のこ
と、磁気特性や物理特性についても微妙な差が出
てくることが知られている。 Therefore, recently, cobalt ions have been
It has now been put into practical use to obtain Co-coated magnetic powder by a method of increasing Hc by allowing Fe 2 O 3 to exist as a cobalt compound on the surface of the particles without being diffused into the particles. However, it is known that such Co-coated magnetic powders have subtle differences not only in surface condition but also in magnetic and physical properties due to differences in manufacturing stages, post-production heat treatment, etc. ing.
この発明は、従来の方法において得られたCo
被着型磁性粉末の欠点が改善された、特に高保磁
力を有しかつ電気抵抗の低いCo被着型磁性粉末
の製法を提供するものである。 This invention is based on Co
The object of the present invention is to provide a method for producing Co-coated magnetic powder, which has improved the drawbacks of coated magnetic powder, and has particularly high coercive force and low electrical resistance.
この発明に係る磁性粉末の製造方法は、γ−
Fe2O3粒子の懸濁液中において、そのγ−Fe2O3
粒子表面をコバルト化合物で被覆した後、その懸
濁液に第１鉄塩水溶液を添加して反応終了時にお
けるその懸濁液のアルカリ濃度を３モル／ない
し12モル／にして得られる磁性粉末を不活性雰
囲気下で120℃ないし200℃の範囲の温度で熱処理
してFe2+／Fe3+が0.03ないし0.20の範囲内になる
ようにすることからなつている。 The method for producing magnetic powder according to the present invention includes γ-
In a suspension of Fe 2 O 3 particles, the γ-Fe 2 O 3
After the particle surface is coated with a cobalt compound, a ferrous salt aqueous solution is added to the suspension, and the alkali concentration of the suspension at the end of the reaction is adjusted to 3 mol/ to 12 mol/ to obtain a magnetic powder. It consists of heat treatment at a temperature in the range of 120°C to 200°C under an inert atmosphere so that Fe 2+ /Fe 3+ is in the range of 0.03 to 0.20.
この発明に係る方法において、針状γ−Fe2O3
粒子は、アルカリ水溶液と充分に混合され、続い
てCo塩を溶解した水溶液を加えて沸点以下加熱
撹拌して所定時間保持することによつて、Co化
合物が被覆される。この場合に使用されるアルカ
リとしては、水酸化ナトリウム、水酸化カリウ
ム、水酸化リチウムなどが挙げられ、そして、
Co塩としては、塩化コバルト、臭化コバルト、
硫酸コバルトなどが挙げられる。また、針状γ−
Fe2O3を懸濁させたアルカリ溶液の濃度は、反応
終了時において、約３モルないし12モル／リツト
ルの範囲になるように制御する。そのアルカリ濃
度が低すぎれば抗磁力Hcが充分には上昇せず、
また高すぎればγ−Fe2O3粒子表面の一部が溶解
して形状が破壊され、抗磁力の上昇が止まり角型
比が低下して好ましくない。更に、鉄状γ−
Fe2O3粒子とCo塩との混合割合は、Co／Fe（Fe2+
＋Fe3+）の比が約0.1ないし20at％の範囲に入る
ようにするのがよい。Co／Fe比が小さすぎれば、
抗磁力Hcの上昇が認められず、またCo／Fe比が
大きすぎれば、粒子が丸くなり、抗磁力が下がる
と共に、分散性が悪化して好ましくない。 In the method according to this invention, acicular γ-Fe 2 O 3
The particles are coated with a Co compound by thoroughly mixing with an aqueous alkaline solution, followed by adding an aqueous solution containing a Co salt dissolved therein, heating and stirring the mixture to a temperature below the boiling point, and holding the mixture for a predetermined period of time. Examples of the alkali used in this case include sodium hydroxide, potassium hydroxide, lithium hydroxide, and
Co salts include cobalt chloride, cobalt bromide,
Examples include cobalt sulfate. In addition, acicular γ-
The concentration of the alkaline solution in which Fe 2 O 3 is suspended is controlled to be in the range of about 3 mol to 12 mol/liter at the end of the reaction. If the alkali concentration is too low, the coercive force Hc will not increase sufficiently,
On the other hand, if it is too high, a part of the surface of the γ-Fe 2 O 3 particles is dissolved and the shape is destroyed, the coercive force stops increasing, and the squareness ratio decreases, which is not preferable. Furthermore, iron-like γ-
The mixing ratio of Fe 2 O 3 particles and Co salt is Co/Fe (Fe 2+
+Fe 3+ ) is preferably in the range of about 0.1 to 20 at%. If the Co/Fe ratio is too small,
If no increase in the coercive force Hc is observed and the Co/Fe ratio is too large, the particles will become round, the coercive force will decrease, and the dispersibility will deteriorate, which is not preferable.
次に、電気抵抗の低下を図るために、Co化合
物で被覆されたγ−Fe2O3粒子を含有する懸濁液
に第１鉄塩の水溶液を添加する。使用できる第１
鉄塩としては、塩化第１第１鉄、硫酸第１鉄など
が挙げられる。続いて、γ−Fe2O3粒子を常法に
従つて取り出した後、不活性雰囲気中で約120℃
ないし200℃の温度で加熱処理する。この加熱処
理は、脱水直後でも、乾燥後でも行つてよい。こ
の加熱処理を、N2ガスなどの不活性雰囲気中で
行うのは、酸素中ではγ−Fe2O3表面が酸化され
て得られる磁性粉末の電気抵抗が上昇するのを防
ぐためである。また加熱処理温度が低くなりすぎ
ると、抵磁力Hcの上昇割合が少なくなり、また
高すぎると磁性粉末の表面のCoが内部に拡散し
やすくなつてドープ型に近づくからこの発明の目
的からして好ましくない。更に、使用する第１鉄
塩の割合は、Fe2+／Fe3+の比が約0.03ないし0.20
の範囲になるようにするのが好ましい。この
Fe2+／Fe3+比が小さすぎると、得られる磁性粉
末の電気抵抗が高くなり効果がなくなり、またそ
の比が大きくなりすぎると、得られる磁性粉末の
磁気特性、消去などの経時変化が大きくなり好ま
しくない。 Next, in order to reduce the electrical resistance, an aqueous solution of a ferrous salt is added to the suspension containing the γ-Fe 2 O 3 particles coated with a Co compound. First available
Examples of iron salts include ferrous chloride and ferrous sulfate. Subsequently, after taking out the γ-Fe 2 O 3 particles according to a conventional method, they were heated at about 120°C in an inert atmosphere.
or heat treatment at a temperature of 200℃. This heat treatment may be performed immediately after dehydration or after drying. The reason why this heat treatment is performed in an inert atmosphere such as N 2 gas is to prevent the γ-Fe 2 O 3 surface from being oxidized in oxygen and thereby increasing the electrical resistance of the resulting magnetic powder. Furthermore, if the heat treatment temperature is too low, the rate of increase in the magnetic resistance Hc will be small, and if it is too high, the Co on the surface of the magnetic powder will easily diffuse into the inside, approaching a doped type. Undesirable. Additionally, the proportion of ferrous salt used is such that the Fe 2+ /Fe 3+ ratio is approximately 0.03 to 0.20.
It is preferable to keep it within the range of . this
If the Fe 2+ /Fe 3+ ratio is too small, the electrical resistance of the obtained magnetic powder will be high and it will be ineffective, and if the ratio is too large, the magnetic properties of the obtained magnetic powder will deteriorate over time, such as erasure. It gets bigger and I don't like it.
以下、この発明を実施例を参照して説明する。 The present invention will be explained below with reference to Examples.
実施例 １
3.3NのNaOH水溶液30リツトルに、鉄状γ−
Fe2O3粒子6.0Kgを添加し、撹拌しながら加熱し
て、70℃に達したときに0.6モル／リツトルの
CoCl2水溶液３リツトルを添加した。その後、更
に加熱撹拌を行つて、100℃６以下の温度で2.5時
間保持した。更に、0.6モル／リツトルのCoCl2水
溶液を１リツトル添加して５時間保持した後、
1.25モル／リツトルのFeCl2水溶液３リツトルを
添加して１時間加熱撹拌した。なお、反応終了時
のアルカリ濃度は3.1Nであつた。これを冷却し、
水洗、脱水した後、N2ガス中にて150℃で２時間
加熱して磁性粉末を得た。この磁性粉末の抗磁力
Hcは585Oe、σsは78emu／ｇであつた。Example 1 Iron-like γ-
Add 6.0Kg of Fe 2 O 3 particles, heat with stirring, and when it reaches 70℃, the concentration of 0.6mol/liter
Three liters of CoCl 2 aqueous solution was added. Thereafter, the mixture was further heated and stirred and maintained at a temperature of 100° C.6 or lower for 2.5 hours. Furthermore, after adding 1 liter of 0.6 mol/liter CoCl 2 aqueous solution and holding for 5 hours,
3 liters of a 1.25 mol/liter FeCl 2 aqueous solution was added, and the mixture was heated and stirred for 1 hour. Note that the alkali concentration at the end of the reaction was 3.1N. Cool this and
After washing with water and dehydrating, it was heated at 150° C. for 2 hours in N 2 gas to obtain magnetic powder. Coercive force of this magnetic powder
Hc was 585 Oe and σs was 78 emu/g.
上記の如くして得られたCo被着酸化鉄粉を下
記に示す組成で約48時間ボールミルで混練して磁
性塗料を調製した。 The Co-coated iron oxide powder obtained as described above was kneaded in a ball mill for about 48 hours to prepare a magnetic paint with the composition shown below.
Co被着磁性酸化鉄粉 100重量部
塩化ビニル・酢酸ビニル共重合体（結合剤）
（VAGH：UCC社製商品名） 17.5 〃
ポリウレタン樹脂（結合剤）（エスタン5702：B.
Fグツドリツチ社製商品名） 7.5 〃
レシチン（分散剤） 2.0 〃
メチルエチルケトン 100 〃
シクロヒキサノン 100 〃
この磁性塗料をポリエチレンテレフタレートか
らなる厚さ20μのフイルム上に乾燥後の厚さが6μ
となるように塗布し、磁気テープを得る。この磁
気テープの電気抵抗は2.0×108Ω／□であつた。Co magnetizable iron oxide powder 100 parts by weight Vinyl chloride/vinyl acetate copolymer (binder)
(VAGH: Product name manufactured by UCC) 17.5 Polyurethane resin (binder) (Estan 5702: B.
7.5 Lecithin (dispersant) 2.0 Methyl ethyl ketone 100 Cyclohyxanone 100 This magnetic paint was placed on a 20μ thick polyethylene terephthalate film with a dry thickness of 6μ.
Apply the magnetic tape so that the magnetic tape is obtained. The electrical resistance of this magnetic tape was 2.0×10 8 Ω/□.
実施例 ２
実施例１の反応溶液を水洗、脱水後、得られた
磁性粉末を空気中で乾燥し、N2ガス中150℃で２
時間加熱処理した。得られた磁性粉末の抗磁力
Hcは585Oeであつて、σsは77emu／ｇであつた。Example 2 After washing the reaction solution of Example 1 with water and dehydrating, the obtained magnetic powder was dried in the air and incubated at 150°C in N2 gas for 2 hours.
Heat treated for hours. Coercive force of the obtained magnetic powder
Hc was 585 Oe and σ s was 77 emu/g.
この磁性粉末を実施例１と同様に用いて磁気テ
ープを作成し、その電気抵抗を測定したところ、
3.0×108Ω／□であつた。 A magnetic tape was prepared using this magnetic powder in the same manner as in Example 1, and its electrical resistance was measured to be 3.0×10 8 Ω/□.
比較例 １
実施例２において加熱処理をせずに空気中で乾
燥することによつて得られた磁性粉末の抗磁力
Hcは540Oeであつて、σsは77emu／ｇであつた。
この磁性粉末を用いて、実施例１と同様にして磁
気テープを作成したところ、その電気抵抗は3.0
×188Ω／□であつた。Comparative Example 1 Coercive force of magnetic powder obtained by drying in air without heat treatment in Example 2
Hc was 540 Oe and σ s was 77 emu/g.
When a magnetic tape was made using this magnetic powder in the same manner as in Example 1, its electrical resistance was 3.0.
It was ×18 8 Ω/□.
比較例 ２
実施例１においてFeCl2溶液を添加せずに、水
洗、脱水後、得られた磁性粉末を空気中で乾燥し
た。この磁性粉末の抵磁力Hcは585Oeであつて、
σsは74emu／ｇであつた。この磁性粉末を用いて
実施例１と同様にして得られた磁気テープの電気
抵抗は3.5×1010Ω／□であつた。Comparative Example 2 The magnetic powder obtained in Example 1 was dried in the air after washing with water and dehydration without adding the FeCl 2 solution. The magnetic resistance Hc of this magnetic powder is 585 Oe,
σ s was 74 emu/g. A magnetic tape obtained using this magnetic powder in the same manner as in Example 1 had an electrical resistance of 3.5×10 10 Ω/□.
なお、図面には、熱処理温度と得えられる磁性
粉末の抗磁力Hcとの関係を示している。図中、
曲線Ａは、Co／Fe3+が3.0at％であつて、Fe2+／
Fe3+が5.0at％である磁性粉末についての関係を
示していて、曲線Ｂは、Co／Fe3+が2.4at％であ
つて、Fe2+／Fe3+が5.0at％である磁性粉末につ
いての関係を示している。 Note that the drawing shows the relationship between the heat treatment temperature and the coercive force Hc of the obtained magnetic powder. In the figure,
Curve A has Co/Fe 3+ of 3.0 at% and Fe 2+ /
Curve B shows the relationship for magnetic powder with Fe 3+ of 5.0 at%, and curve B shows the relationship for magnetic powder with Co/Fe 3+ of 2.4 at% and Fe 2+ /Fe 3+ of 5.0 at%. The relationship for powders is shown.
図面はこの発明に係る方法で得られた磁性粉末
の抗磁力Hcと熱処理温度との関係を示すグラフ
である。
The drawing is a graph showing the relationship between the coercive force Hc of the magnetic powder obtained by the method according to the present invention and the heat treatment temperature.
Claims (1)
−Fe2O3粒子表面をコバルト化合物で被覆した
後、その懸濁液に第１鉄塩水溶液を添加して反応
終了時におけるその懸濁液のアルカリ濃度を３モ
ル／ないし12モル／にして得られる磁性粉末
を不活性雰囲気下で120℃ないし200℃の範囲の温
度で熱処理してFe2+／Fe3+が0.03ないし0.20の範
囲内になるようにしてCoを被着させることを特
徴とする磁性粉末の製法。1 In a suspension of γ-Fe 2 O 3 particles, the γ
-After the surface of the Fe 2 O 3 particles is coated with a cobalt compound, an aqueous ferrous salt solution is added to the suspension so that the alkaline concentration of the suspension at the end of the reaction is 3 mol/ to 12 mol/. The magnetic powder obtained is heat treated in an inert atmosphere at a temperature in the range of 120°C to 200°C so that Fe 2+ /Fe 3+ is in the range of 0.03 to 0.20 to deposit Co. A method for producing magnetic powder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57045197A JPS58161927A (en) | 1982-03-19 | 1982-03-19 | Manufacture of magnetic powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57045197A JPS58161927A (en) | 1982-03-19 | 1982-03-19 | Manufacture of magnetic powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58161927A JPS58161927A (en) | 1983-09-26 |
| JPH034489B2 true JPH034489B2 (en) | 1991-01-23 |
Family
ID=12712540
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57045197A Granted JPS58161927A (en) | 1982-03-19 | 1982-03-19 | Manufacture of magnetic powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58161927A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3631194A1 (en) * | 1986-09-13 | 1988-03-24 | Bayer Ag | MAGNETIC IRON OXIDE PIGMENTS AND METHOD FOR THE PRODUCTION THEREOF |
| JPH02263407A (en) * | 1989-04-04 | 1990-10-26 | Showa Denko Kk | Continuous manufacture of magnetic iron oxide powder for magnetic recording and device therefor |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54124297A (en) * | 1978-03-20 | 1979-09-27 | Fuji Photo Film Co Ltd | Ferromagnetic powder |
| JPS56104721A (en) * | 1980-01-22 | 1981-08-20 | Tdk Corp | Preparation of magnetic powder |
-
1982
- 1982-03-19 JP JP57045197A patent/JPS58161927A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58161927A (en) | 1983-09-26 |
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