JPS632812A - Production of particulate powder of lamellate ba ferrite for magnetic recording - Google Patents
Production of particulate powder of lamellate ba ferrite for magnetic recordingInfo
- Publication number
- JPS632812A JPS632812A JP14770986A JP14770986A JPS632812A JP S632812 A JPS632812 A JP S632812A JP 14770986 A JP14770986 A JP 14770986A JP 14770986 A JP14770986 A JP 14770986A JP S632812 A JPS632812 A JP S632812A
- Authority
- JP
- Japan
- Prior art keywords
- zinc
- particles
- ferrite
- plate
- shaped
- 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.)
- Granted
Links
- 229910000859 α-Fe Inorganic materials 0.000 title claims abstract description 77
- 239000000843 powder Substances 0.000 title claims abstract description 12
- 230000005291 magnetic effect Effects 0.000 title claims description 16
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 239000002245 particle Substances 0.000 claims abstract description 84
- 239000010419 fine particle Substances 0.000 claims abstract description 52
- 230000004907 flux Effects 0.000 claims abstract description 27
- 239000011701 zinc Substances 0.000 claims abstract description 25
- 229940007718 zinc hydroxide Drugs 0.000 claims abstract description 25
- 229910021511 zinc hydroxide Inorganic materials 0.000 claims abstract description 25
- UGZADUVQMDAIAO-UHFFFAOYSA-L zinc hydroxide Chemical compound [OH-].[OH-].[Zn+2] UGZADUVQMDAIAO-UHFFFAOYSA-L 0.000 claims abstract description 24
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 23
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000010438 heat treatment Methods 0.000 claims abstract description 21
- 239000007864 aqueous solution Substances 0.000 claims description 17
- 238000010304 firing Methods 0.000 claims description 16
- 241000276425 Xiphophorus maculatus Species 0.000 claims description 8
- 238000002844 melting Methods 0.000 claims description 7
- 230000008018 melting Effects 0.000 claims description 7
- 238000005406 washing Methods 0.000 claims description 2
- 230000005415 magnetization Effects 0.000 abstract description 38
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 abstract description 8
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 abstract description 8
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 abstract description 6
- 238000001914 filtration Methods 0.000 abstract description 4
- 150000004820 halides Chemical class 0.000 abstract description 4
- 239000011780 sodium chloride Substances 0.000 abstract description 4
- VNDYJBBGRKZCSX-UHFFFAOYSA-L zinc bromide Chemical compound Br[Zn]Br VNDYJBBGRKZCSX-UHFFFAOYSA-L 0.000 abstract description 4
- 239000011592 zinc chloride Substances 0.000 abstract description 4
- 235000005074 zinc chloride Nutrition 0.000 abstract description 4
- UAYWVJHJZHQCIE-UHFFFAOYSA-L zinc iodide Chemical compound I[Zn]I UAYWVJHJZHQCIE-UHFFFAOYSA-L 0.000 abstract description 4
- ZOIORXHNWRGPMV-UHFFFAOYSA-N acetic acid;zinc Chemical compound [Zn].CC(O)=O.CC(O)=O ZOIORXHNWRGPMV-UHFFFAOYSA-N 0.000 abstract description 3
- 239000000463 material Substances 0.000 abstract description 3
- 239000004246 zinc acetate Substances 0.000 abstract description 3
- 229910052783 alkali metal Inorganic materials 0.000 abstract description 2
- 150000001340 alkali metals Chemical class 0.000 abstract description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 abstract description 2
- 150000001342 alkaline earth metals Chemical class 0.000 abstract description 2
- 238000001035 drying Methods 0.000 abstract description 2
- 229940102001 zinc bromide Drugs 0.000 abstract description 2
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 abstract description 2
- 229960001763 zinc sulfate Drugs 0.000 abstract description 2
- 229910000368 zinc sulfate Inorganic materials 0.000 abstract description 2
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 abstract 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 abstract 1
- WDIHJSXYQDMJHN-UHFFFAOYSA-L barium chloride Chemical compound [Cl-].[Cl-].[Ba+2] WDIHJSXYQDMJHN-UHFFFAOYSA-L 0.000 abstract 1
- 229910001626 barium chloride Inorganic materials 0.000 abstract 1
- 238000001354 calcination Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 description 19
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 14
- 239000006104 solid solution Substances 0.000 description 11
- 238000001027 hydrothermal synthesis Methods 0.000 description 9
- 239000011787 zinc oxide Substances 0.000 description 7
- 238000004458 analytical method Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 238000005245 sintering Methods 0.000 description 5
- 239000012670 alkaline solution Substances 0.000 description 4
- 238000000151 deposition Methods 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 239000007858 starting material Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- CPELXLSAUQHCOX-UHFFFAOYSA-N Hydrogen bromide Chemical compound Br CPELXLSAUQHCOX-UHFFFAOYSA-N 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000005294 ferromagnetic effect Effects 0.000 description 2
- 238000010335 hydrothermal treatment Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000000696 magnetic material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910001422 barium ion Inorganic materials 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005307 ferromagnetism Effects 0.000 description 1
- 239000010436 fluorite Substances 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000007496 glass forming Methods 0.000 description 1
- 229910000042 hydrogen bromide Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 239000006249 magnetic particle Substances 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
Landscapes
- Compounds Of Iron (AREA)
- Hard Magnetic Materials (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、磁気記録用板状Ｂａフェライト微粒子粉末の
製造法に関するものであり、詳しくは、粒子表面に亜鉛
の水酸化物が沈着されている板状Ｂａフェライト粒子を
融剤の存在下、該融剤の融点以上の温度で加熱焼成する
ことにより大きな磁化値を有する板状Ｂａフェライト微
粒子粉末を提供することを目的とする。[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for producing plate-shaped Ba ferrite fine particle powder for magnetic recording. The object of the present invention is to provide plate-shaped Ba ferrite fine particles having a large magnetization value by heating and firing plate-shaped Ba ferrite particles in the presence of a flux at a temperature higher than the melting point of the flux.
近年、例えば、特開昭５５−８６１０３号公報にも述べ
られている通り、大きな磁化値と適当な抗磁力とを有し
、且つ、適当な平均粒度を有する強磁性の非針状粒子が
記録用磁性材料、特に垂直磁気記録用磁性材料として要
望されつつある。In recent years, for example, as described in JP-A-55-86103, ferromagnetic non-acicular particles having a large magnetization value, an appropriate coercive force, and an appropriate average particle size have been recorded. It is increasingly being desired as a magnetic material for applications, especially for perpendicular magnetic recording.
−般に、強磁性の非針状粒子としてはＢａフェライト粒
子がよく知られている。- Generally, Ba ferrite particles are well known as ferromagnetic non-acicular particles.
従来から板状Ｂａフェライトの製造法の一つとして、Ｂ
ａイオンとＦｅ１ｌとが含まれたアルカリ性懸、濁液を
反応装置としてオートクレーブを用いて水熱処理する方
法（以下、これを単に水熱合成法という、）が知られて
いる。Conventionally, one of the manufacturing methods of plate-shaped Ba ferrite is B
A method is known in which an alkaline suspension or suspension containing a ions and Fe11 is hydrothermally treated using an autoclave as a reaction device (hereinafter simply referred to as a hydrothermal synthesis method).
先ず、磁気特性について言えば、磁気記録用板状Ｂａフ
ェライト粒子粉末の磁化値は、出来るだけ大きいことが
必要であり、この事実は、例えば特開昭５６−１４９３
２８号公報の「・・・・磁気記録媒体材料に使われるマ
グネトブランバイトフェライトにっいては可能な限り大
きな飽和磁化・・・・が要求される。」と記載されてい
る通りである。First, regarding magnetic properties, it is necessary that the magnetization value of plate-shaped Ba ferrite particles for magnetic recording be as large as possible.
This is as stated in Publication No. 28, "...The magnetoblanbite ferrite used as a magnetic recording medium material is required to have as large a saturation magnetization as possible."
また、抗磁力は、−般に３００〜１５０００ｅ程度のも
のが要求されており、上記水熱合成法において生成りａ
フェライト微粒子粉末の抗磁力を低減させ適当な抗磁力
とする為にフェライト中のＦｅａ［ｌの一部をＴｉ（５
）及びＣｏ０Ｄ又はＣａ１）並びにＭｎ、 Ｚｎｓ Ｎ
ｉ等の２価の金属イオンＭ■で置換することが提案され
ている。In addition, the coercive force is generally required to be about 300 to 15,000 e, and the a
In order to reduce the coercive force of the ferrite fine particle powder and obtain an appropriate coercive force, a part of Fe[l in the ferrite is replaced with Ti(5
) and Co0D or Ca1) and Mn, Zns N
It has been proposed to substitute with a divalent metal ion M such as i.
次に、磁気記録用板状Ｂａフェライト微粒子粉末の粒度
について言えば、出来るだけ微細な粒子、殊に、０．３
μ−以下であることが必要である。Next, regarding the particle size of the plate-shaped Ba ferrite fine particle powder for magnetic recording, the particles should be as fine as possible, especially 0.3
It is necessary that it is less than or equal to μ.
この事実は、例えば、特開昭５６−１２５２１９号公報
の［・・・・垂直磁化記録が面内記録に対して、その有
意性が明らかとなるのは、記録波長が１μｍ以下の領域
である。しかしてこの波長領域で十分な記録・再生を行
うためには、上記フェライトの結晶粒径は、略０．３μ
■以下が望ましい、しかし、０．０１μ−程度となると
、所望の強磁性を呈しないため、適切な結晶粒径として
は、０．０１−０．３μｌ程度が要求される。」なる記
載等の通りである。This fact can be seen, for example, in Japanese Unexamined Patent Publication No. 125219/1983 [...The significance of perpendicular magnetization recording compared to longitudinal recording becomes clear in the region where the recording wavelength is 1 μm or less. . However, in order to perform sufficient recording and reproduction in this wavelength range, the crystal grain size of the ferrite must be approximately 0.3μ.
(2) or less is desirable; however, if it is about 0.01 μl, it will not exhibit the desired ferromagnetism, so a suitable crystal grain size is required to be about 0.01-0.3 μl. ” is as stated.
大きな磁化値と適当な抗磁力とを有し、且つ、適当な平
均粒度を有する板状Ｂａフェライト粒子粉末は、現在量
も要求されているところであるが、上述した通りの水熱
合成法においては、反応条件を選ぶことによって各種の
Ｈａフェライト粒子が沈澱してくる。この沈澱粒子は通
常六角板状を呈しており、生成条件によってその粒度分
布や平均径が相違することによって磁気的性質が異なる
。Plate-shaped Ba ferrite particles having a large magnetization value, an appropriate coercive force, and an appropriate average particle size are currently required in quantity, but in the hydrothermal synthesis method as described above, Various types of Ha ferrite particles are precipitated by selecting reaction conditions. These precipitated particles usually have a hexagonal plate shape, and their particle size distribution and average diameter vary depending on the generation conditions, so their magnetic properties vary.
本発明者は、永年に亘り、水熱合成法による板状Ｂａフ
ェライト粒子の研究及び開発に携わっているものである
が、その過程において反応条件によって平均径０．０５
〜０．３μ−を有する板状Ｂａフェライト微粒子が得ら
れるという知見を得ている。The present inventor has been involved in the research and development of plate-shaped Ba ferrite particles using a hydrothermal synthesis method for many years.
It has been found that plate-shaped Ba ferrite fine particles having a particle size of ~0.3 μ- can be obtained.
しかしながら、上記平均径０．０５〜０．３ μ−を有
する板状Ｂａフェライト粒子は、抗磁力を１５０００ｅ
以下に制御しようとする場合には、磁化値を５０ｅｍｕ
７ｇ以上に維持することが困難なものである。However, the plate-shaped Ba ferrite particles having the average diameter of 0.05 to 0.3 μ- have a coercive force of 15,000 e
If you want to control the magnetization value below 50 emu
It is difficult to maintain the weight above 7g.
また、従来、水熱合成法により水溶液中から生成した板
状Ｂａフェライト微粒子を８００℃以上の温度で加熱焼
成して磁化値を向上させる方法が知られている（特公昭
６０−１２９７３号公報）。Furthermore, a method has been known in the past in which plate-shaped Ba ferrite fine particles produced from an aqueous solution by hydrothermal synthesis are heated and fired at a temperature of 800°C or higher to improve the magnetization value (Japanese Patent Publication No. 12973/1983). .
しかしながら、この方法による場合、磁化値は、加熱焼
成温度が高くなる程大きくなる傾向があり、大きな磁化
値、殊に５７〜６０ ｅｍｕ／ｇ程度以上を得ようとす
れば９００℃以上の高温が必要であり、この場合には、
粒子及び粒子相・瓦間における焼結が顕著となって塊状
粒子となってしまい、磁気記録用磁性粒子粉末として好
ましくない。However, when using this method, the magnetization value tends to increase as the heating and firing temperature increases, and in order to obtain a large magnetization value, especially about 57 to 60 emu/g or more, a high temperature of 900 ° C or more is required. necessary, and in this case,
Sintering between particles, particle phases, and tiles becomes significant, resulting in lumpy particles, which are not preferred as magnetic particles for magnetic recording.
また、加熱焼成して得られた板状Ｂａフェライト微粒子
の抗磁力を１５０００ｅ以下に制御する為には、前述し
た抗磁力低減剤を多量に添加しなければならず、このこ
とは磁化値を低下させる原因となり、大きな磁化値、殊
に、５７〜６０ｅｍｕ／ｇ以上を維持しながら抗磁力を
３００〜１５０００ｅの範囲に制御することは困難であ
った。In addition, in order to control the coercive force of the plate-shaped Ba ferrite fine particles obtained by heating and firing to 15,000e or less, it is necessary to add a large amount of the above-mentioned coercive force reducing agent, which reduces the magnetization value. Therefore, it was difficult to control the coercive force in the range of 300 to 15,000 e while maintaining a large magnetization value, especially 57 to 60 emu/g or more.
そこで、大きな磁化値と適当な抗磁力とを有し、且つ、
適当な平均粒度を有する板状Ｂａフェライト粒子を得る
方法の確立が強く要望されている。Therefore, it has a large magnetization value and an appropriate coercive force, and
There is a strong desire to establish a method for obtaining plate-shaped Ba ferrite particles having a suitable average particle size.
本発明者は、上述したところに鑑み、水熱処理法におい
て平均径０．０５〜０．３μ僧を有する板状Ｂａフェラ
イト粒子の抗磁力を３００〜１５０００ｅとし、且つ、
磁化値を更に高めるべく種々研究を重ねた結果、本発明
に到達したものである。In view of the above, the present inventor set the coercive force of plate-shaped Ba ferrite particles having an average diameter of 0.05 to 0.3μ in a hydrothermal treatment method to 300 to 15000e, and
The present invention was achieved as a result of various studies aimed at further increasing the magnetization value.
即ち、本発明は、板状Ｂａフェライト微粒子をρ■４．
０〜１２．０の亜鉛を含む水溶液中に懸濁させ、粒子表
面に亜鉛の水酸化物が沈着している板状Ｂａフェライト
微粒子を得、該粒子を濾別、乾燥し、次いで、融剤の存
在下、該融剤の融点以上の温度で加熱焼成した後、該加
熱焼成物を洗浄して融剤を除去することからなる磁気記
録用板状Ｂａフェライト微粒子粉末の製造法である。That is, in the present invention, the plate-like Ba ferrite fine particles are ρ■4.
Platy Ba ferrite fine particles with zinc hydroxide deposited on the surface of the particles are obtained by suspending them in an aqueous solution containing zinc of 0 to 12.0%.The particles are filtered and dried, and then a flux is added. This is a method for producing a plate-shaped Ba ferrite fine particle powder for magnetic recording, which comprises heating and firing the product at a temperature equal to or higher than the melting point of the flux in the presence of the powder, and then washing the heated and fired product to remove the flux.
先ず、本発明において最も重要な点は、板状Ｂａフェラ
イト粒子をｐＨ４，０〜１２．０の亜鉛を含む水溶液中
に懸濁させ、粒子表面に亜鉛の水酸化物が沈着している
板状Ｂａフェライト微粒子を得、該粒子を濾別、乾燥し
、次いで、融剤の存在下、該融剤の融点以上の温度で加
熱焼成した場合には、板状Ｈａミツエライト子の磁化値
を効果的に大きくすることができる点である。First, the most important point in the present invention is that plate-shaped Ba ferrite particles are suspended in an aqueous solution containing zinc with a pH of 4.0 to 12.0, and plate-shaped Ba ferrite particles with zinc hydroxide deposited on the surface of the particles are suspended. When Ba ferrite fine particles are obtained, the particles are filtered and dried, and then heated and fired in the presence of a flux at a temperature higher than the melting point of the flux, the magnetization value of the plate-shaped Ha mitzerite particles can be effectively reduced. The point is that it can be made larger.
本発明者は、粒子表面に亜鉛の水酸化物が沈着している
板状Ｂａフェライト粒子を６００〜９００℃の温度範囲
で加熱焼成した場合には、板状Ｂａフェライト粒子表面
に亜鉛を固溶させることができ、その結果、大きな磁化
値を有する板状Ｂａフェライト粒子が得られるという知
見を既に得ている（特願昭６１−１８８３４号）、この
方法による場合には、磁化値を大きくすることができる
と同時に抗磁力を低下させるという効果も得られるが、
この効果は亜鉛を板状Ｂａフェライト粒子の粒子表面に
亜鉛を固溶させることによって初めて発現されるもので
あり、水熱処理法において板状Ｂａフェライト微粒子の
生成反応にあたり亜鉛を添加する（例えば、特公昭４６
−３５４５号公報、前出特公昭６０−１２９７３号公報
）場合及び板状Ｂａフェライト粒子の粒子表面を亜鉛の
酸化物及び／又は水酸化物で被覆（特開昭５８−５６２
３２号公報）のいずれの場合にも発現されない。The present inventor has discovered that when plate-shaped Ba ferrite particles with zinc hydroxide deposited on the particle surface are heated and fired at a temperature range of 600 to 900°C, zinc is dissolved in solid solution on the surface of the plate-shaped Ba ferrite particles. It has already been found that as a result, plate-shaped Ba ferrite particles with a large magnetization value can be obtained (Japanese Patent Application No. 18834/1983).When using this method, the magnetization value is increased. At the same time, the effect of lowering the coercive force can be obtained.
This effect is first manifested by solid solution of zinc on the particle surface of plate-shaped Ba ferrite particles, and zinc is added during the formation reaction of plate-shaped Ba ferrite fine particles in the hydrothermal treatment method (for example, Kosho 46
-3545, the aforementioned Japanese Patent Publication No. 60-12973), and the surface of plate-shaped Ba ferrite particles is coated with zinc oxide and/or hydroxide (Japanese Patent Laid-Open No. 58-562).
No. 32) is not expressed in any of the cases.
上記方法において、板状Ｂａフェライト微粒子の粒子表
面に固溶している亜鉛の量が増加する程、効果的に磁化
値を大きくすることができ、粒子表面に固溶している亜
鉛の量の制御は、粒子表面に亜鉛の水酸化物を沈着させ
る際のｐＨと亜鉛添加量とを調整することによって行わ
れる。In the above method, as the amount of zinc dissolved in the particle surface of the plate-shaped Ba ferrite fine particles increases, the magnetization value can be effectively increased, and the amount of zinc dissolved in the particle surface increases. Control is performed by adjusting the pH and the amount of zinc added when depositing zinc hydroxide on the particle surface.
本発明者は、上記方法において、板状Ｂａフェライト粒
子の磁化値を更に高めるべく種々検討を重ね、粒子表面
に亜鉛の水酸化物が沈着している板状’Ｂａフェライト
粒子を加熱焼成するにあたり融剤を存在させた場合には
更に磁化値を高めることができるという全く新規な知見
を得たのである。In the above method, the present inventor has conducted various studies in order to further increase the magnetization value of plate-shaped Ba ferrite particles, and has found that when heating and firing plate-shaped 'Ba ferrite particles with zinc hydroxide deposited on the particle surface, They obtained the completely new finding that the magnetization value can be further increased when a flux is present.
本発明において、大きな磁化値を有する板状Ｂａフェラ
イト粒子が得られる理由については、未だ明らかではな
いが、本発明者は、粒子表面に亜鉛の水酸化物が沈着し
ている板状Ｂａフェライト粒子を加熱焼成して亜鉛を固
溶させた場合、板状Ｂａフェライト粒子を融剤の存在下
で加熱焼成する場合に比べ、大きな磁化値が得られてい
ることから、粒子表面に固溶された亜鉛と融剤との相乗
効果によるものと考えている。Although the reason why plate-shaped Ba ferrite particles having a large magnetization value can be obtained in the present invention is not yet clear, the present inventor has discovered that plate-shaped Ba ferrite particles in which zinc hydroxide is deposited on the particle surface. When zinc is dissolved in solid solution by heating and firing, a larger magnetization value is obtained compared to when plate-shaped Ba ferrite particles are heated and fired in the presence of a flux. We believe that this is due to the synergistic effect of zinc and flux.
尚、従来、板状Ｂａフェライト粒子を加熱焼成するにあ
たり、融剤を存在させるものとして例えば、特開昭６０
−１５１２２４号公報及び特開昭６０−１６１３４５号
公報に記載の方法があるが、これら方法により得られた
板状Ｂａフェライト粒子の磁化値は高々５８ｅｔｓｕ／
ｇである・
次に、本発明実施にあたっての諸条件について述べる。Conventionally, when heating and firing plate-shaped Ba ferrite particles, a fluxing agent is present, for example, in JP-A-60
There are methods described in JP-A-151224 and JP-A-60-161345, but the magnetization value of plate-shaped Ba ferrite particles obtained by these methods is at most 58 etsu/
g. Next, various conditions for implementing the present invention will be described.
本発明における出発原料としての板状Ｂａフェライト微
粒子とは、板状Ｂａ０−ｎＦｅＪｓ（３，５≦ｎ≦６）
微粒子及びこれらに前述した周知の抗磁力低減剤を添加
したものをいい、水熱合成法により水溶液中から生成し
た板状Ｂａフェライト微粒子はもちろん、これを加熱焼
成したもの、水溶液中からＢａイオンとＰｅイオンとを
沈澱させ、該沈澱物を加熱焼成する所謂共沈法により得
られた板状Ｂａフェライト微粒子及びＢａフェライトの
成分原料とガラス形成物質とを混合、溶融した後、該溶
融物を急速冷却する所謂ガラス溶融法により得られた板
状Ｂａフェライト微粒子のいずれをも用いることができ
る。The plate-shaped Ba ferrite fine particles as a starting material in the present invention are plate-shaped Ba0-nFeJs (3,5≦n≦6)
It refers to fine particles and those to which the well-known coercive force reducing agent mentioned above is added, including plate-shaped Ba ferrite fine particles produced from an aqueous solution by a hydrothermal synthesis method, those obtained by heating and firing these, and Ba ions and Ba ferrite particles from an aqueous solution. After mixing and melting plate-shaped Ba ferrite fine particles obtained by a so-called co-precipitation method in which Pe ions are precipitated and the precipitate is heated and fired, a glass-forming substance is mixed and melted, and the melt is rapidly Any plate-shaped Ba ferrite fine particles obtained by a so-called glass melting method involving cooling can be used.
本発明における亜鉛の水酸化物の沈着は、板状Ｂａフェ
ライト微粒子をｐＨ４，０〜１２．０の亜鉛を含む水溶
液中に懸濁させればよい。In the present invention, zinc hydroxide can be deposited by suspending plate-shaped Ba ferrite fine particles in an aqueous solution containing zinc having a pH of 4.0 to 12.0.
亜鉛を含む水溶液としては、塩化亜鉛、臭化亜鉛、ヨウ
化亜鉛等のハロゲン化物、硝酸亜鉛、硫酸亜鉛、酢酸亜
鉛等を使用することができる。As the aqueous solution containing zinc, halides such as zinc chloride, zinc bromide, and zinc iodide, zinc nitrate, zinc sulfate, zinc acetate, and the like can be used.
ｐＨが４以下又は１２以上である場合には、亜鉛の沈着
が困難となる。When the pH is 4 or less or 12 or more, it becomes difficult to deposit zinc.
粒子表面への亜鉛の水酸化物の沈着量は、ｐＨ８〜１０
付近を最高値としてｐＨが高くなる程増加する傾向にあ
る。The amount of zinc hydroxide deposited on the particle surface varies between pH 8 and 10.
It tends to increase as the pH becomes higher, with the highest value being around.
本発明における融剤としては、アルカリ金属、アルカリ
土類金属のハロゲン化物及び硫酸塩等の一種又は二種以
上を用いることができ、磁化値の向上及び経済性を考慮
すれば、ＮａＣｌ 、ＢａＣ１□、５ｒＣｈ 、ＫＣＩ
等が好ましい。As the flux in the present invention, one or more kinds of halides and sulfates of alkali metals and alkaline earth metals can be used. Considering the improvement of magnetization value and economical efficiency, NaCl, BaC1□ , 5rCh , KCI
etc. are preferred.
本発明における融剤の量は、板状Ｂａフェライト粒子に
対し３〜４００重量％である。３重景％以下である場合
には、加熱焼成時に粒子及び粒子相互間で焼結が生起し
、好ましくない、４００重量％以上である場合にも本発
明の目的を達成することができるが必要以上に添加する
意味がない。The amount of flux in the present invention is 3 to 400% by weight based on the plate-shaped Ba ferrite particles. If it is less than 3% by weight, sintering will occur between particles and particles during heating and firing, which is undesirable, and even if it is more than 400% by weight, the purpose of the present invention can be achieved, but it is necessary. There is no point in adding more than that.
本発明における加熱焼成温度は、融点以上１０００℃以
下であり、１０００℃以上では得られる板状Ｂａフェラ
イト微粒子の粒子成長が生起し好ましくない。The heating and sintering temperature in the present invention is higher than the melting point and lower than 1000° C. If it is higher than 1000° C., particle growth of the obtained plate-shaped Ba ferrite fine particles occurs, which is not preferable.
本発明における融剤の洗浄は、水及び塩酸、酢酸、硝酸
、臭化水素等の水溶液の一種又は二種以上を用いて行う
ことができる。The fluxing agent in the present invention can be washed using one or more of water and aqueous solutions such as hydrochloric acid, acetic acid, nitric acid, and hydrogen bromide.
本発明における板状Ｂａフェライト微粒子への亜鉛の固
溶量は０．２〜５．０重量％である。The solid solution amount of zinc in the plate-shaped Ba ferrite fine particles in the present invention is 0.2 to 5.0% by weight.
０．２重量％以下である場合には、本発明の目的を十分
達成することができない。If it is less than 0.2% by weight, the object of the present invention cannot be fully achieved.
５．０重量％以上である場合にも本発明の目的を達成す
ることはできるが必要以上に添加することは意味がない
。Although the purpose of the present invention can be achieved even if the amount is 5.0% by weight or more, there is no point in adding more than necessary.
次に、実施例及び比較例により本発明を説明す尚、以下
の実施例並びに比較例における粒子の平均径は、電子顕
微鏡写真により測定した値である。Next, the present invention will be explained with reference to Examples and Comparative Examples. The average diameter of particles in the following Examples and Comparative Examples is a value measured using an electron micrograph.
また、磁化値及び抗磁力は粉末状態で１０ ＫＯｅの磁
場において測定したものである。Further, the magnetization value and coercive force were measured in a powder state in a magnetic field of 10 KOe.
実施例１ 水熱合成法により、Ｆｅに対し９．５モル％のＢａ。Example 1 9.5 mol% Ba based on Fe by hydrothermal synthesis.
８．５モル％のＧｏ及び２，８モル％のＴｉを含有する
板状Ｂａフェライト微粒子を得た。得られた微粒子は、
平均径０，０７μ繭、磁性は抗磁力Ｈｃが１３００ｅ、
磁化値が１０ｅ■ｕ／ｇであった。Platy Ba ferrite fine particles containing 8.5 mol% Go and 2.8 mol% Ti were obtained. The obtained fine particles are
Cocoon with average diameter 0.07μ, magnetic coercive force Hc 1300e,
The magnetization value was 10 e■u/g.
上記粒子１００ｇを０．０７ｍｏｌの塩化亜鉛水溶液中
に分散混合し、Ｐ）＋ ６．０において粒子表面に亜鉛
の水酸化物を沈着させた後、濾別、乾燥した。100 g of the above particles were dispersed and mixed in a 0.07 mol zinc chloride aqueous solution, and after depositing zinc hydroxide on the particle surface at P) + 6.0, the particles were separated by filtration and dried.
次いで、粒子表面に亜鉛の水酸化物を沈着している板状
Ｂａフェライト微粒子粉末５０ｇに１００ｇのＮａＣ１
からなる融剤（板状Ｂａフェライト微粒子に対し２００
重量％に該当する。）を含む水溶液を添加し、水分を蒸
発後、８１０℃にて大気中１時間加熱焼成した。Next, 100 g of NaCl was added to 50 g of plate-shaped Ba ferrite fine particles powder with zinc hydroxide deposited on the particle surface.
(200% for plate-shaped Ba ferrite fine particles)
Applies to weight%. ) was added thereto, and after evaporating the moisture, the mixture was heated and baked at 810° C. in the air for 1 hour.
加熱焼成して得られた微粒子は、平均径０．０７μ■で
あり、磁性は抗磁力Ｈｃが６８００ｅ、磁化値が６５．
８ｅｍｕ／ｇであった・
この微粒子は、化学分析の結果、アルカリ溶液中で加熱
抽出される亜鉛酸化物、亜鉛水酸化物が検出されないこ
とから亜鉛が固溶したものと認められ、亜鉛の固溶量は
、螢光Ｘ線分析の結果、２．５重量％であった。The fine particles obtained by heating and firing have an average diameter of 0.07 μm, a coercive force Hc of 6800e, and a magnetization value of 65.
8 emu/g As a result of chemical analysis, zinc oxide and zinc hydroxide, which are heated and extracted in an alkaline solution, were not detected, so it was recognized that zinc was dissolved in solid solution. The amount dissolved was 2.5% by weight as a result of fluorescent X-ray analysis.
尚、融剤を存在させないで加熱焼成した以外は、上記と
同様にして得られたＣＯ及びＴｉを含有した板状Ｂａフ
ェライト微粒子は、平均径０゜０７μｍ、磁性は抗磁力
が７４００ｅ、 磁化値が６１．Ｏｅｍｕ／ｇであった
。Incidentally, the plate-shaped Ba ferrite fine particles containing CO and Ti obtained in the same manner as above except that heating and firing without the presence of a flux had an average diameter of 0°07 μm, a coercive force of 7400e, and a magnetization value. is 61. It was Oemu/g.
実施例２ 水熱合成法により、Ｆｅに対し１０８０モル％のＢａ。Example 2 1080 mol% Ba based on Fe by hydrothermal synthesis.
７．０モル％のＣｏ及び２．０モル％のＴｉを含有する
板状８ａフ工ライト微粒子を得た。得られた微粒子は、
平均径０．１ μ鴎、磁性は抗磁力Ｈｅが１４００ｅ、
磁化（直が１１．０ｅｍｕ／ｇであった。Platy 8a fluorite fine particles containing 7.0 mol% Co and 2.0 mol% Ti were obtained. The obtained fine particles are
The average diameter is 0.1μ, the magnetism is coercive force He is 1400e,
Magnetization (direction was 11.0 emu/g).
上記微粒子１００ｇを０．０５ｍｏｌの硝酸亜鉛水溶液
中に分散混合し、ｐＨ１０，０において粒子表面に亜鉛
の水酸化物を沈着させた後、戸別、乾燥した。100 g of the above fine particles were dispersed and mixed in a 0.05 mol zinc nitrate aqueous solution, and after depositing zinc hydroxide on the surface of the particles at pH 10.0, they were dried door to door.
次いで、粒子表面に亜鉛の水酸化物を沈着している板状
Ｂａフェライト微粒子粉末５０ ｇに２０ Ｈの５ｒＣ
Ｉｚ と１０ｇのＮａＣ１とからなる融剤（板状Ｂａフ
ェライト微粒子に対し６０重量％に該当する。）を含む
水溶液を添加し、水分を蒸発後、９００℃にて大気中２
時間加熱焼成した。Next, 50 g of plate-shaped Ba ferrite fine particles with zinc hydroxide deposited on the particle surface was heated with 5rC at 20 H.
An aqueous solution containing a flux (corresponding to 60% by weight based on the plate-shaped Ba ferrite particles) consisting of Iz and 10 g of NaCl was added, and after evaporating the water, it was heated to 2
It was heated and baked for an hour.
加熱焼成して得られた微粒子は、平均径０．１ μ請で
あり、磁性は抗磁力Ｈｃが９０００ｅ、 ＠比値が６５
．７ｅ■ｕ／ｇであった。The fine particles obtained by heating and firing have an average diameter of 0.1 μm, a coercive force Hc of 9000e, and a ratio value of 65.
．． It was 7e■u/g.
この微粒子は、化学分析の結果、アルカリ溶液中で加熱
抽出される亜鉛酸化物、亜鉛水酸化物が検出されないこ
とから亜鉛が固溶したものと認められ、亜鉛の固溶量は
、螢光Ｘ線分析の結果、２．９重量％であった。As a result of chemical analysis, zinc oxide and zinc hydroxide, which are heated and extracted in an alkaline solution, were not detected, so it was recognized that zinc was dissolved in solid solution. As a result of line analysis, it was 2.9% by weight.
尚、融剤を存在させないで加熱焼成した以外は、上記と
同様にして得られたＧｏ及びＴｉを含有した板状Ｂａフ
ェライトｉ粒子は、平均径０．１μｍ 、 ６１１性は
抗磁力が９５００ｅ、磁化値が６１．５ｅ頚ｕ／ｇであ
った。Incidentally, the plate-shaped Ba ferrite i particles containing Go and Ti obtained in the same manner as above except that heating and firing without the presence of a flux had an average diameter of 0.1 μm, a coercive force of 9500 e, and a 611 property of 9500 e. The magnetization value was 61.5e neck u/g.
実施例３
水熱合成法により、Ｆｅに対し１０．０モル％のＢａを
含有する板状Ｂａフェライト微粒子を得た。得られた微
粒子は、平均径０．１１μｍ、磁性は抗磁力Ｈｅが４８
００ｅ、 １ｉｆｆ化値が３１．０ｅｓｕ／ｇであった
。Example 3 Platy Ba ferrite fine particles containing 10.0 mol % of Ba based on Fe were obtained by a hydrothermal synthesis method. The obtained fine particles had an average diameter of 0.11 μm and a coercive force He of 48 μm.
00e, the 1iff conversion value was 31.0 esu/g.
上記粒子１００ｇを０．０８ ｍｏｌの酢酸亜鉛水溶液
中に分散混合し、ｐＨ７，０において粒子表面に亜鉛の
水酸化物を沈着させた後、濾別、乾燥した。100 g of the above particles were dispersed and mixed in a 0.08 mol zinc acetate aqueous solution, and after depositing zinc hydroxide on the particle surface at pH 7.0, the particles were separated by filtration and dried.
次いで、粒子表面に亜鉛の水酸化物を沈着している板状
Ｂａフェライト微粒子粉末５０ｇに２００ｇのにＣ１か
らなる融剤（板状Ｂａフェライト微粒子に対し４００重
量％に該当する。）を含む水溶液を添加し、水分を蒸発
後、８５０℃にて大気中１．５時間加熱焼成した。Next, an aqueous solution containing 200 g of a flux consisting of C1 (corresponding to 400% by weight with respect to the plate-like Ba ferrite fine particles) is added to 50 g of plate-shaped Ba ferrite fine particles on which zinc hydroxide is deposited on the particle surface. was added, the moisture was evaporated, and the mixture was heated and baked at 850° C. in the air for 1.5 hours.
加熱焼成して得られた微粒子は、平均径０．１１μ園で
あり、磁性は抗磁力Ｈｅが１０８００ｅ 、 Ｔ６ｉ化
値が６６．５ｅｍｕ／ｇであった。The fine particles obtained by heating and firing had an average diameter of 0.11 μm, a coercive force He of 10800e, and a T6i value of 66.5 emu/g.
また、この微粒子は、化学分析の結果、アルカリ溶液中
で加熱抽出される亜鉛酸化物、亜鉛水酸化物が検出され
ないことから亜鉛が固溶したちのと認められ、亜鉛の固
溶量は、螢光Ｘ線分析の結果、３．０重量％であった。In addition, as a result of chemical analysis, zinc oxide and zinc hydroxide, which are heated and extracted in an alkaline solution, were not detected, so it was recognized that zinc was dissolved in solid solution, and the amount of zinc solid solution was As a result of fluorescent X-ray analysis, it was 3.0% by weight.
尚、融剤を存在させないで加熱焼成した以外は、上記と
同様にして得られた板状Ｂａフェライト微粒子は、平均
径０．１１μ腸、磁性は抗磁力１１４００ｓ、磁化値が
６０．５ｅｍｕ／ｇであった。In addition, the plate-shaped Ba ferrite fine particles obtained in the same manner as above except that they were heated and fired in the absence of a flux had an average diameter of 0.11 μ, a coercive force of 11400 s, and a magnetization value of 60.5 emu/g. Met.
実施例４
水熱合成法により、Ｆｅに対し９．０モル％のＢａを含
有する板状Ｂａフェライト微粒子を得た。得られた微粒
子は、平均径０．１５μ篇、磁性は抗磁力Ｈｅが４５０
０ｅ、磁化値が２８．０ｅｓｕ／ｇであった。Example 4 Platy Ba ferrite fine particles containing 9.0 mol % of Ba based on Fe were obtained by a hydrothermal synthesis method. The obtained fine particles had an average diameter of 0.15 μm and a coercive force He of 450 μm.
0e, and the magnetization value was 28.0 esu/g.
上記粒子１００ｇを０．０９ ａ＋ｏｌの塩化亜鉛水溶
液中に分散混合し、ｐＨ９，０において粒子表面に亜鉛
の水酸化物を沈着させた後、濾別、乾燥した。100 g of the above particles were dispersed and mixed in a 0.09 a+ol zinc chloride aqueous solution to deposit zinc hydroxide on the particle surface at pH 9.0, followed by filtering and drying.
次いで、粒子表面に亜鉛の水酸化物を沈着している板状
Ｂａフェライト微粒子粉末５０ｇに１５ｇの［１ａＣＩ
ｚと５ｇのＭＣＩ とからなる融ｗｉ（板状Ｂａフェラ
イト微粒子に対し４０重量％に該当する。）を含む水溶
液を添加し、水分を蒸発後、９１０℃にて大気中０．５
時間加熱焼成した。Next, 15 g of [1aCI
An aqueous solution containing molten steel (corresponding to 40% by weight based on the plate-shaped Ba ferrite particles) consisting of Z and 5 g of MCI was added, and after evaporating the moisture, it was heated to 0.5 g in air at 910°C.
It was heated and baked for an hour.
加熱焼成して得られた微粒子は、平均径０．１５μ−で
あり、磁性は抗磁力Ｈｃが９８００ｅＳ磁化値が６７．
１ｅｍｕ／ｇであった・
また、この微粒子は、化学分析の結果、アルカリ溶液中
で加熱抽出される亜鉛酸化物、亜鉛水酸化物が検出され
ないことから亜鉛が固溶したものと認められ、亜鉛の固
溶量は、螢光Ｘ線分析の結果、４．０重量％であった。The fine particles obtained by heating and firing have an average diameter of 0.15 μ-, and a coercive force Hc of 9800 eS and a magnetization value of 67.
1 emu/g. Also, as a result of chemical analysis, zinc oxide and zinc hydroxide, which are heated and extracted in an alkaline solution, were not detected, so it was recognized that zinc was dissolved in solid solution. The amount of solid solution was 4.0% by weight as a result of fluorescent X-ray analysis.
向、融剤を存在させないで加熱焼成した以外は、上記と
同様にして得られた板状Ｂａフェライト微粒子は、平均
径０．１５μｍ、磁性は抗磁力１０３００ｅ、磁化値が
６４．３ｅｍｕ／ｇであった。The plate-shaped Ba ferrite fine particles obtained in the same manner as above, except that heating and sintering was carried out in the absence of a flux, had an average diameter of 0.15 μm, a coercive force of 10300 e, and a magnetization value of 64.3 emu/g. there were.
比較例１〜１４
出発原料の種類、Ｚｎの種類並びに添加量、融剤の種類
並びに添加量及び加熱処理温度並びに時間を種々変化さ
せた以外は実施例１と同様にして板状Ｂａフェライト粒
子粉末を得た。Comparative Examples 1 to 14 Platy Ba ferrite particles were prepared in the same manner as in Example 1, except that the type of starting material, the type and amount of Zn added, the type and amount of flux, and the heat treatment temperature and time were varied. I got it.
尚、比較例９の出発原料粒子としては、平均径［＋、１
２／ＪＩＢ 、Ｎ性は抗磁力１（ｃが１１００ｅ、磁化
値が１２６ｗｕ／ｇであるＣＯ５Ｔｉ及びＺｎを含有す
る板状Ｂａ〕エライト粒子粉末（Ｃｏ／ＦｅＧＤ ＝
８．０原子％、Ｔｉ／Ｆｅ１）＝２．１原子％及びＺｎ
／ＦｅＱＥ ＝ ４．０原子％）を用いた。Note that the starting material particles of Comparative Example 9 had an average diameter [+, 1
2/JIB, N property is coercive force 1 (plate-like Ba containing CO5Ti and Zn with c of 1100e and magnetization value of 126 wu/g) elite particle powder (Co/FeGD =
8.0 at%, Ti/Fe1)=2.1 at% and Zn
/FeQE = 4.0 at%) was used.
この時の主要製造条件及び緒特性を表１に示す。Table 1 shows the main manufacturing conditions and characteristics at this time.
比較例１３及び１４で得られた板状Ｂａフェライト粒子
は、化学分析の結果、アルカリ水溶液中で加熱抽出され
る亜鉛酸化物、亜鉛水酸化物が検出されたことから、亜
鉛が粒子表面に亜鉛酸化物、亜鉛水酸化物として存在し
ており、固溶していないものであることが確認された。As a result of chemical analysis, the plate-shaped Ba ferrite particles obtained in Comparative Examples 13 and 14 detected zinc oxide and zinc hydroxide that were extracted by heating in an alkaline aqueous solution. It was confirmed that the zinc oxide existed as an oxide and zinc hydroxide, and was not dissolved in solid solution.
また、比較例１．２．５．７．９．１１及び１２で得ら
れた板状Ｂａフェライト微粒子粉末は、電子顕微鏡観察
の結果、粒子及び粒子相互間で焼結が生起した粒子であ
った。Further, as a result of electron microscopic observation, the plate-shaped Ba ferrite fine particle powders obtained in Comparative Examples 1.2.5.7.9.11 and 12 were particles in which sintering occurred between the particles and between the particles. .
本発明における板状Ｂａフェライト微粒子粉末の製造法
によれば、前出実施例に示した通り、１０ ＫＯｅの磁
場における磁化値が大きく、抗磁力が３００〜１５００
０ｅであって適当な粒度を有する板状Ｂａフェライト微
粒子を得ることができるので、磁気記録用磁性材料、特
に、垂直磁気記録用材料として最適である。According to the manufacturing method of the plate-shaped Ba ferrite fine particles of the present invention, as shown in the previous example, the magnetization value in a magnetic field of 10 KOe is large and the coercive force is 300 to 1500.
Since it is possible to obtain plate-shaped Ba ferrite fine particles having a particle size of 0e and a suitable particle size, it is optimal as a magnetic material for magnetic recording, particularly as a material for perpendicular magnetic recording.
Claims (1)
０の亜鉛を含む水溶液中に懸濁させ、粒子表面に亜鉛の
水酸化物が沈着している板状Ｂａフェライト微粒子を得
、該粒子を濾別、乾燥し、次いで、融剤の存在下、該融
剤の融点以上の温度で加熱焼成した後、該加熱焼成物を
洗浄して融剤を除去することを特徴とする磁気記録用板
状Ｂａフェライト微粒子粉末の製造法。(1) Platy Ba ferrite fine particles at pH 4.0 to 12.
Platy Ba ferrite fine particles are obtained by suspending them in an aqueous solution containing 0.0% zinc to obtain plate-shaped Ba ferrite fine particles having zinc hydroxide deposited on the surface of the particles.The particles are filtered and dried, and then, in the presence of a flux, A method for producing a plate-shaped Ba ferrite fine particle powder for magnetic recording, which comprises heating and firing at a temperature equal to or higher than the melting point of the flux, and then washing the heated and fired product to remove the flux.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14770986A JPS632812A (en) | 1986-06-24 | 1986-06-24 | Production of particulate powder of lamellate ba ferrite for magnetic recording |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14770986A JPS632812A (en) | 1986-06-24 | 1986-06-24 | Production of particulate powder of lamellate ba ferrite for magnetic recording |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS632812A true JPS632812A (en) | 1988-01-07 |
| JPH0524869B2 JPH0524869B2 (en) | 1993-04-09 |
Family
ID=15436443
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14770986A Granted JPS632812A (en) | 1986-06-24 | 1986-06-24 | Production of particulate powder of lamellate ba ferrite for magnetic recording |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS632812A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5118575A (en) * | 1989-04-22 | 1992-06-02 | Toda Kogyo Corp. | Plate-like composite ferrite fine particles for magnetic recording and a process for producing the same |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5856232A (en) * | 1981-09-30 | 1983-04-02 | Toshiba Corp | Magnetic recording medium |
| JPS60161343A (en) * | 1984-01-26 | 1985-08-23 | Hitachi Maxell Ltd | Preparation of hexagonal ferrite magnetic powder |
-
1986
- 1986-06-24 JP JP14770986A patent/JPS632812A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5856232A (en) * | 1981-09-30 | 1983-04-02 | Toshiba Corp | Magnetic recording medium |
| JPS60161343A (en) * | 1984-01-26 | 1985-08-23 | Hitachi Maxell Ltd | Preparation of hexagonal ferrite magnetic powder |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5118575A (en) * | 1989-04-22 | 1992-06-02 | Toda Kogyo Corp. | Plate-like composite ferrite fine particles for magnetic recording and a process for producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0524869B2 (en) | 1993-04-09 |
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