JPH0581970B2 - - Google Patents
Info
- Publication number
- JPH0581970B2 JPH0581970B2 JP61295369A JP29536986A JPH0581970B2 JP H0581970 B2 JPH0581970 B2 JP H0581970B2 JP 61295369 A JP61295369 A JP 61295369A JP 29536986 A JP29536986 A JP 29536986A JP H0581970 B2 JPH0581970 B2 JP H0581970B2
- Authority
- JP
- Japan
- Prior art keywords
- powder
- magnetic
- inorganic fine
- hexagonal ferrite
- fine powder
- 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
- 239000000843 powder Substances 0.000 claims description 32
- 229910000859 α-Fe Inorganic materials 0.000 claims description 30
- 239000006247 magnetic powder Substances 0.000 claims description 21
- 238000004519 manufacturing process Methods 0.000 claims description 17
- 239000002245 particle Substances 0.000 claims description 15
- 238000007496 glass forming Methods 0.000 claims description 11
- 239000013078 crystal Substances 0.000 claims description 8
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 7
- 239000002253 acid Substances 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 2
- 238000002844 melting Methods 0.000 claims description 2
- 230000008018 melting Effects 0.000 claims description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 239000003973 paint Substances 0.000 description 5
- 238000010298 pulverizing process Methods 0.000 description 5
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000003746 surface roughness Effects 0.000 description 3
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 229910010413 TiO 2 Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 239000002178 crystalline material Substances 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- IIZPXYDJLKNOIY-JXPKJXOSSA-N 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine Chemical compound CCCCCCCCCCCCCCCC(=O)OC[C@H](COP([O-])(=O)OCC[N+](C)(C)C)OC(=O)CCC\C=C/C\C=C/C\C=C/C\C=C/CCCCC IIZPXYDJLKNOIY-JXPKJXOSSA-N 0.000 description 1
- 229910020599 Co 3 O 4 Inorganic materials 0.000 description 1
- 229910020517 Co—Ti Inorganic materials 0.000 description 1
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 1
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 238000010908 decantation Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 239000000787 lecithin Substances 0.000 description 1
- 229940067606 lecithin Drugs 0.000 description 1
- 235000010445 lecithin Nutrition 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000012046 mixed solvent Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920006267 polyester film Polymers 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
- 238000001238 wet grinding Methods 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
Description
［発明の目的］
（産業上の利用分野）
本発明は、高密度磁気記録媒体の製造に用いら
れる磁性粉末の製造方法に係り、特に粒子間の凝
集力が弱く分散性に優れた六方晶系フエライトか
らなる磁性粉末の製造方法に関する。
（従来の技術）
従来から、高密度磁気記録媒体を製造する方法
として、六方晶系フエライトの微粉末を結合剤、
溶剤および各種添加剤とともに混合して磁性塗料
を作製し、この磁性塗料を支持体上に塗布する方
法が知られている。
また、単一の六方晶系フエライトでは、保磁力
が大きく記録時に磁気ヘツドが飽和して磁気記録
が困難となるため、六方晶系フエライトの構成原
子の一部を特定の他の原子で置換することによ
り、その保磁力を磁気記録に適する値まで低減さ
せることも知られている。
このような磁気記録に用いる六方晶系フエライ
トの磁性粉末を製造する方法としては、六方晶系
フエライトの基本成分、保磁力低減のための置換
成分およびガラス形成成分を混合して加熱溶融さ
せ、この溶融物を急速に冷却して非晶質体とし、
これを熱処理して六方晶系フエライト微粒子を析
出させた後、これを粉砕して、得られた微粉末を
リン酸や酢酸等の希酸で処理してガラス形成成分
を溶解除去することによつて六方晶系フエライト
を分離抽出するといういわゆるガラス結晶化法が
よく用いられている。
（発明が解決しようとする問題点）
ところで、このような従来の製造方法によつて
得られるBaフエライト等の六方晶系フエライト
の磁性粉末は、平均粒系が500〜800Åと非常に微
細であり、粒子形状が六角板状で、その板状比も
３〜５程度であるため、非常に凝集しやすい。
最近、高出力の磁気記録媒体の要求に対して、
磁性層における磁性粉末の充填量を高めることが
試みられているが、上記したように磁性粉末が凝
集しやすいために、磁性塗料の作製時に結合剤に
対する分散性を阻害して、形成した磁性層の表面
荒さが大きくなる等の欠点を生じ、これにより
Ｓ／Ｎ比の低下を招き、十分に性能が発揮されな
かつた。
本発明はこのような従来の事情に対処してなさ
れたもので、粒子間の凝集が少なく、分散性を向
上させた磁性粉末を製造する方法を提供すること
を目的とする。
［発明の構成］
（問題点を解決するための手段）
本発明の磁性粉末の製造方法は、六方晶系フエ
ライトの基本成分、保磁力低減のための置換成分
およびガラス形成成分の混合物を加熱溶融させた
後、急冷して非晶質体とする工程と、この非晶質
体に熱処理を施して六方晶系フエライトの結晶を
析出させ、これを乾式粉砕する工程と、得られた
結晶粉末に非磁性無機質微粉末を添加して湿式粉
砕を行つた後、希酸によつてガラス形成成分を溶
解除去して六方晶系フエライトの結晶を抽出する
工程とからなることを特徴としている。
本発明に使用する非磁性無機質微粉末として
は、不溶性で、その粒径が0.04〜0.5μｍの範囲と
なるものが適しており、例えばアルミナ、煙霧質
シリカ、ジルコニア、マグネシヤ等が挙げられ、
特にアルミナ粉末が適している。この非磁性無機
質微粉末の粒径が0.04μｍ未満であるとフエライ
ト粒子間への分散が均一に行なわれずフエライト
粉末の分散性向上の効果が十分得られず、また
0.5μｍを超えてもその効果が十分得られない。
そして、この非磁性無機質微粉末の添加量は、
熱処理後の結晶粉末に対して0.05〜1.0重量％の
範囲が好ましい。非磁性無機質微粉末の添加量が
0.05重量％未満であると分散性向上の効果が十分
に得られず、1.0重量％を超えると得られる六方
晶系フエライトの磁性に悪影響をあたえる可能性
がある。
なお、本発明方法は、
一般式：AFe12-xMxO19
（式中、ＡはBa、Sr、Pbから選ばれた１種以上
の元素を、ＭはIn、Zn−Ge、Zn−Nb、Zn−Ｖ、
Co−Ti、Co−Geの１種以上の置換元素または元
素の組合わせを、またＸは０〜2.5の正の数をそ
れぞれ表す。）で示されるような置換型六方晶系
フエライトからなる磁性粉末の製造に適している
が、これに限定されるものではない。
（作用）
本発明の磁性粉末の製造方法において、熱処理
後の結晶物を湿式粉砕する際に非磁性無機質微粉
末を添加することによつて、この湿式粉砕時に結
晶物と十分に混合され、次いで結晶物中のガラス
形成成分を希酸で溶解する際に非磁性無機質微粉
末粒子が六方晶系フエライトの粒子間に入り込む
ので、六方晶系フエライト間の凝集力が低下して
分散性を向上する。
（実施例）
次に本発明をマグネトプランバイト型Baフエ
ライトからなる磁性粉末の製造に適用した実施例
について詳細に説明する。
実施例
まず、Baフエライトのフエライト成分Fe2O3
と、保磁力低減のための置換成分TiO2、CoOと、
ガラス形成成分BaO、B2O3とをBaO20〜50mol
％、B2O320〜50mol％、Fe2O312〜40mol％、
TiO20〜6mol％、CoO0〜6mol％の組成比となる
ように、BaCO3、Fe2O3、TiO2、Co3O4および
H3BO3を所定量秤量し、これらを十分に混合し
た後、この混合物を白金るつぼに収容し、高周波
誘電加熱ヒータを用いて1300℃で加熱溶融して、
次いでこの溶融物を水冷高速双ロール上で圧延急
冷して40〜50μｍ厚の非晶質体を作成した。次
に、この非晶質体を耐熱容器に充填し電気炉内に
収容して、50℃／時間の速度で800℃まで昇温し、
800℃で６時間保持して、Baフエライトの結晶を
析出させた。次いで、得られたBaフエライトの
結晶をブラウン型クラツシヤーを用いて乾式粉砕
し粉砕粒度100〜300μｍの粉末とした。次に、こ
の乾式粉砕した結晶粉末に対して200重量％の水
と0.5重量％のアルミナ（Al2O3、平均粒径0.1μ
ｍ）粉末を加えて、ボールミルによりアルミナボ
ールを使用して、約10時間湿式粉砕を行つて平均
粒径約1μｍの微粉末とした。次に、湿式微粉砕
後の微粉末を10％の酢酸溶液で洗浄してガラス形
成成分（BaO、B2O3）を溶解除去し、ついでデ
カンテーシヨン法により水洗を繰返してガラス形
成成分の完全な除去を行い、脱水および乾燥する
ことにより平均粒径0.05μｍの六方晶径Baフエラ
イト粉末を得た。
このようにして得たBaフエライト粉末100ｇを
メチルエチルケトンートルエンの１：１混合溶剤
200ｇに懸濁させ、これにレシチン３ｇを加えて
サンドグラインダーを用いて４時間分散した。つ
いで、この分散液にポリウレタン樹脂の35重量％
酢酸メチル溶液50ｇを加え、さらに２時間分散し
た後、過して磁性塗料を作製した。この磁性塗
料を厚さ25μｍのポリエステルフイルム上にロー
ルコータ法にて磁界配向下で塗布し、乾燥トンネ
ル炉によつて100℃において乾燥することにより、
膜厚10μｍの磁性記録層を形成し磁気記録体を製
造した。
また、本発明方法との比較のため、ボールミル
による湿式粉砕の際にアルミナ粉末を添加しない
以外は実施例と同一条件で磁性粉末を作製した。
この磁性粉末を用いて実施例と同一条件で磁気記
録体を製造した。
これらの磁気記録媒体の平均表面粗さと角形比
を調べた結果を次表に示す。なお、平均表面粗さ
はターリーステツプにて調査した。
[Objective of the Invention] (Industrial Application Field) The present invention relates to a method for producing magnetic powder used in the production of high-density magnetic recording media, and particularly relates to a method for producing magnetic powder used in the production of high-density magnetic recording media. The present invention relates to a method for producing magnetic powder made of ferrite. (Prior Art) Conventionally, as a method for manufacturing high-density magnetic recording media, fine powder of hexagonal ferrite is used as a binder and
A method is known in which a magnetic paint is prepared by mixing it with a solvent and various additives, and this magnetic paint is coated on a support. In addition, a single hexagonal ferrite has a large coercive force that saturates the magnetic head during recording, making magnetic recording difficult. Therefore, some of the constituent atoms of the hexagonal ferrite are replaced with specific other atoms. It is also known that the coercive force can be reduced to a value suitable for magnetic recording. A method for producing magnetic powder of hexagonal ferrite used for magnetic recording is to mix the basic components of hexagonal ferrite, a replacement component for reducing coercive force, and a glass-forming component, and heat and melt the mixture. Rapidly cool the melt to form an amorphous body,
After heat-treating this to precipitate hexagonal ferrite fine particles, it is crushed and the resulting fine powder is treated with dilute acid such as phosphoric acid or acetic acid to dissolve and remove the glass-forming components. The so-called glass crystallization method, in which hexagonal ferrite is separated and extracted, is often used. (Problems to be Solved by the Invention) By the way, the magnetic powder of hexagonal ferrite such as Ba ferrite obtained by such conventional production methods is extremely fine with an average grain size of 500 to 800 Å. Since the particle shape is hexagonal plate-like and the plate-like ratio is about 3 to 5, it is very easy to aggregate. Recently, in response to the demand for high-output magnetic recording media,
Attempts have been made to increase the amount of magnetic powder packed in the magnetic layer, but as mentioned above, the magnetic powder tends to aggregate, which inhibits the dispersibility of the binder during the preparation of the magnetic paint, resulting in a lower magnetic layer. This resulted in drawbacks such as increased surface roughness, which led to a decrease in the S/N ratio and insufficient performance. The present invention has been made in response to the above-mentioned conventional circumstances, and an object of the present invention is to provide a method for producing magnetic powder with less agglomeration between particles and improved dispersibility. [Structure of the Invention] (Means for Solving the Problems) The method for producing magnetic powder of the present invention involves heating and melting a mixture of a basic component of hexagonal ferrite, a substitute component for reducing coercive force, and a glass-forming component. After that, there is a step of rapidly cooling to form an amorphous body, a step of heat-treating this amorphous body to precipitate hexagonal ferrite crystals, and a step of dry-pulverizing this, and a step of turning the obtained crystalline powder into It is characterized by the steps of adding non-magnetic inorganic fine powder and performing wet pulverization, and then dissolving and removing glass-forming components with dilute acid to extract hexagonal ferrite crystals. The non-magnetic inorganic fine powder used in the present invention is suitably insoluble and has a particle size in the range of 0.04 to 0.5 μm, such as alumina, atomized silica, zirconia, magnesia, etc.
Alumina powder is particularly suitable. If the particle size of this non-magnetic inorganic fine powder is less than 0.04 μm, the dispersion between the ferrite particles will not be uniform, and the effect of improving the dispersibility of the ferrite powder will not be achieved sufficiently.
Even if it exceeds 0.5 μm, the effect cannot be sufficiently obtained. The amount of this non-magnetic inorganic fine powder added is
It is preferably in the range of 0.05 to 1.0% by weight based on the crystal powder after heat treatment. The amount of non-magnetic inorganic fine powder added is
If it is less than 0.05% by weight, the effect of improving dispersibility will not be sufficiently obtained, and if it exceeds 1.0% by weight, it may have an adverse effect on the magnetism of the hexagonal ferrite obtained. The method of the present invention has a general formula: AFe 12-x M x O 19 (wherein A is one or more elements selected from Ba, Sr, and Pb, and M is In, Zn-Ge, and Zn- Nb, Zn-V,
Each represents one or more substituting elements or a combination of elements such as Co-Ti and Co-Ge, and X represents a positive number from 0 to 2.5. ), but is not limited thereto. (Function) In the method for producing magnetic powder of the present invention, by adding non-magnetic inorganic fine powder when wet-pulverizing the crystalline material after heat treatment, the non-magnetic inorganic fine powder is sufficiently mixed with the crystalline material during this wet-pulverization, and then When the glass-forming components in the crystalline substance are dissolved with dilute acid, non-magnetic inorganic fine powder particles enter between the hexagonal ferrite particles, reducing the cohesive force between the hexagonal ferrite particles and improving dispersibility. . (Example) Next, an example in which the present invention is applied to the production of magnetic powder made of magnetoplumbite-type Ba ferrite will be described in detail. Example First, the ferrite component of Ba ferrite is Fe 2 O 3
and replacement components TiO 2 and CoO to reduce coercive force,
Glass- forming component BaO, B2O3 and BaO20-50mol
%, B2O3 20-50mol %, Fe2O3 12-40mol %,
BaCO 3 , Fe 2 O 3 , TiO 2 , Co 3 O 4 and
After weighing a predetermined amount of H 3 BO 3 and thoroughly mixing them, the mixture is placed in a platinum crucible and heated and melted at 1300°C using a high frequency dielectric heater.
This melt was then rapidly cooled by rolling on water-cooled high-speed twin rolls to produce an amorphous body with a thickness of 40 to 50 μm. Next, this amorphous material is filled into a heat-resistant container, placed in an electric furnace, and heated to 800°C at a rate of 50°C/hour.
The temperature was maintained at 800°C for 6 hours to precipitate Ba ferrite crystals. Next, the obtained Ba ferrite crystals were dry-pulverized using a Brown type crusher to obtain a powder having a crushed particle size of 100 to 300 μm. Next, 200 wt% water and 0.5 wt% alumina ( Al2O3 , average particle size 0.1μ) were added to this dry-milled crystalline powder.
m) The powder was added and wet milled for about 10 hours using an alumina ball in a ball mill to obtain a fine powder with an average particle size of about 1 μm. Next, the fine powder after wet pulverization is washed with a 10% acetic acid solution to dissolve and remove glass-forming components (BaO, B 2 O 3 ), and then water washing is repeated using a decantation method to remove the glass-forming components. By completely removing, dehydrating and drying, a hexagonal Ba ferrite powder with an average particle size of 0.05 μm was obtained. 100g of the Ba ferrite powder thus obtained was mixed with a 1:1 mixed solvent of methyl ethyl ketone and toluene.
200 g of the suspension was suspended, 3 g of lecithin was added thereto, and the mixture was dispersed for 4 hours using a sand grinder. Then, 35% by weight of polyurethane resin was added to this dispersion.
After adding 50 g of methyl acetate solution and dispersing for another 2 hours, the mixture was filtered to produce a magnetic paint. By applying this magnetic paint onto a 25 μm thick polyester film using a roll coater method under magnetic field orientation and drying it at 100°C in a drying tunnel furnace,
A magnetic recording body was manufactured by forming a magnetic recording layer with a thickness of 10 μm. Further, for comparison with the method of the present invention, magnetic powder was produced under the same conditions as in the example except that alumina powder was not added during wet milling using a ball mill.
A magnetic recording body was manufactured using this magnetic powder under the same conditions as in the example. The results of examining the average surface roughness and squareness ratio of these magnetic recording media are shown in the following table. Note that the average surface roughness was investigated using a Turley step.
【表】
上記の表からも明らかなように、この実施例で
作製した磁性粉末は、従来の方法により作製した
磁性粉末に比べて凝集塊も小さく分散性に優れて
いるため、表面の平滑性と高い配向度を同時に満
足して優れた磁性塗膜を形成することができる。
［発明の効果］
以上の説明からも明らかなように、本発明の磁
性粉末の製造方法によれば、希酸によりガラス形
成成分を溶解除去する際に、非磁性無機質微粉末
を添加することによつて、得られる六法晶系フエ
ライト粉末の粒子間に非磁性無機質微粉末が混入
して、六方晶系フエライト間の凝集力を低下させ
るので、分散性に優れた磁性粉末が得られる。[Table] As is clear from the table above, the magnetic powder produced in this example has smaller agglomerates and better dispersibility than magnetic powder produced by conventional methods, so it has a smooth surface. It is possible to form an excellent magnetic coating film that satisfies both the high degree of orientation and the high degree of orientation. [Effects of the Invention] As is clear from the above explanation, according to the method for producing magnetic powder of the present invention, it is possible to add non-magnetic inorganic fine powder when dissolving and removing glass-forming components with dilute acid. Therefore, the non-magnetic inorganic fine powder is mixed between the particles of the obtained hexagonal ferrite powder and reduces the cohesive force between the hexagonal ferrite particles, so that a magnetic powder with excellent dispersibility can be obtained.
Claims (1)
のための置換成分およびガラス形成成分の混合物
を加熱溶融させた後、急冷して非晶質体とする工
程と、この非晶質体に熱処理を施して六方晶系フ
エライトの結晶を析出させ、これを乾式粉砕する
工程と、得られた結晶粉末に非磁性無機質微粉末
を添加して湿式粉砕を行つた後、希酸によつてガ
ラス形成成分を溶解除去して六方晶系フエライト
の結晶を抽出する工程とからなることを特徴とす
る磁性粉末の製造方法。 ２ 非磁性無機質微粉末の粒径が、0.04〜0.5μｍ
の範囲である特許請求の範囲第１項記載の磁性粉
末の製造方法。 ３ 非磁性無機質微粉末の添加量が、乾式粉砕し
た熱処理後の結晶粉末に対して0.05〜1.0重量％
の範囲である特許請求の範囲第１項または第２項
記載の磁性粉末の製造方法。 ４ 非磁性無機質微粉末がアルミナ粉末である特
許請求の範囲第１項ないし第３項のいずれか１項
記載の磁性粉末の製造方法。[Claims] 1. A step of heating and melting a mixture of a basic component of hexagonal ferrite, a substitute component for reducing coercive force, and a glass-forming component, and then rapidly cooling the mixture to form an amorphous body; The crystalloids are heat-treated to precipitate hexagonal ferrite crystals, which are then dry-pulverized. Non-magnetic inorganic fine powder is added to the resulting crystalline powder, wet-pulverized, and then diluted with dilute acid. 1. A method for producing magnetic powder, comprising the step of dissolving and removing glass-forming components to extract hexagonal ferrite crystals. 2 The particle size of the non-magnetic inorganic fine powder is 0.04 to 0.5 μm
A method for producing magnetic powder according to claim 1, which is within the scope of claim 1. 3 The amount of non-magnetic inorganic fine powder added is 0.05 to 1.0% by weight based on the dry-pulverized crystal powder after heat treatment.
A method for producing magnetic powder according to claim 1 or 2, which falls within the scope of claim 1 or 2. 4. The method for producing magnetic powder according to any one of claims 1 to 3, wherein the nonmagnetic inorganic fine powder is alumina powder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61295369A JPS63148412A (en) | 1986-12-11 | 1986-12-11 | Production of magnetic powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61295369A JPS63148412A (en) | 1986-12-11 | 1986-12-11 | Production of magnetic powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63148412A JPS63148412A (en) | 1988-06-21 |
| JPH0581970B2 true JPH0581970B2 (en) | 1993-11-17 |
Family
ID=17819734
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61295369A Granted JPS63148412A (en) | 1986-12-11 | 1986-12-11 | Production of magnetic powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63148412A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010080608A (en) * | 2008-09-25 | 2010-04-08 | Fujifilm Corp | Method of manufacturing hexagonal ferrite magnetic powder, magnetic recording medium, and method of manufacturing the same |
| JP5697399B2 (en) * | 2010-03-31 | 2015-04-08 | 富士フイルム株式会社 | Hexagonal ferrite magnetic particles and method for producing the same, magnetic powder for magnetic recording medium, and magnetic recording medium |
-
1986
- 1986-12-11 JP JP61295369A patent/JPS63148412A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63148412A (en) | 1988-06-21 |
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