JPH01222409A - Manufacture of needle-like magnetic iron-oxide particle and powder - Google Patents
Manufacture of needle-like magnetic iron-oxide particle and powderInfo
- Publication number
- JPH01222409A JPH01222409A JP63048386A JP4838688A JPH01222409A JP H01222409 A JPH01222409 A JP H01222409A JP 63048386 A JP63048386 A JP 63048386A JP 4838688 A JP4838688 A JP 4838688A JP H01222409 A JPH01222409 A JP H01222409A
- Authority
- JP
- Japan
- Prior art keywords
- particles
- needle
- grains
- aqueous suspension
- hematite
- 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.)
- Pending
Links
- 239000002245 particle Substances 0.000 title claims abstract description 212
- 239000000843 powder Substances 0.000 title claims abstract description 22
- JEIPFZHSYJVQDO-UHFFFAOYSA-N ferric oxide Chemical compound O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 title claims abstract description 12
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 title claims description 47
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 229960005191 ferric oxide Drugs 0.000 title 1
- 235000013980 iron oxide Nutrition 0.000 title 1
- 229910052595 hematite Inorganic materials 0.000 claims abstract description 38
- 239000011019 hematite Substances 0.000 claims abstract description 38
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 claims abstract description 37
- 239000007900 aqueous suspension Substances 0.000 claims abstract description 36
- 239000007864 aqueous solution Substances 0.000 claims abstract description 25
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910003153 β-FeOOH Inorganic materials 0.000 claims abstract description 12
- 238000010335 hydrothermal treatment Methods 0.000 claims abstract description 9
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 7
- 239000011574 phosphorus Substances 0.000 claims abstract description 7
- -1 phosphorus compound Chemical class 0.000 claims abstract description 7
- 239000000725 suspension Substances 0.000 claims abstract description 5
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 claims description 11
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- 238000000034 method Methods 0.000 abstract description 12
- 238000010438 heat treatment Methods 0.000 abstract description 8
- 230000001590 oxidative effect Effects 0.000 abstract description 6
- 238000006243 chemical reaction Methods 0.000 abstract description 4
- 210000001787 dendrite Anatomy 0.000 abstract 3
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 abstract 1
- 239000011148 porous material Substances 0.000 description 17
- 230000000052 comparative effect Effects 0.000 description 13
- 239000002244 precipitate Substances 0.000 description 13
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 8
- 239000007858 starting material Substances 0.000 description 8
- 239000013078 crystal Substances 0.000 description 7
- 238000000635 electron micrograph Methods 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 238000002441 X-ray diffraction Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 238000001035 drying Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 229910052598 goethite Inorganic materials 0.000 description 5
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 description 5
- 238000005406 washing Methods 0.000 description 5
- 238000001914 filtration Methods 0.000 description 4
- 230000005415 magnetization Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 235000011007 phosphoric acid Nutrition 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 230000018044 dehydration Effects 0.000 description 3
- 238000006297 dehydration reaction Methods 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001493 electron microscopy Methods 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 1
- UEZVMMHDMIWARA-UHFFFAOYSA-N Metaphosphoric acid Chemical compound OP(=O)=O UEZVMMHDMIWARA-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- XPPKVPWEQAFLFU-UHFFFAOYSA-N diphosphoric acid Chemical compound OP(O)(=O)OP(O)(O)=O XPPKVPWEQAFLFU-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229960002089 ferrous chloride Drugs 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229910021506 iron(II) hydroxide Inorganic materials 0.000 description 1
- NCNCGGDMXMBVIA-UHFFFAOYSA-L iron(ii) hydroxide Chemical compound [OH-].[OH-].[Fe+2] NCNCGGDMXMBVIA-UHFFFAOYSA-L 0.000 description 1
- 239000006249 magnetic particle Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- ACVYVLVWPXVTIT-UHFFFAOYSA-N phosphinic acid Chemical compound O[PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-N 0.000 description 1
- 150000003018 phosphorus compounds Chemical class 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 229940005657 pyrophosphoric acid Drugs 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- ISIJQEHRDSCQIU-UHFFFAOYSA-N tert-butyl 2,7-diazaspiro[4.5]decane-7-carboxylate Chemical compound C1N(C(=O)OC(C)(C)C)CCCC11CNCC1 ISIJQEHRDSCQIU-UHFFFAOYSA-N 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Landscapes
- Hard Magnetic Materials (AREA)
- Compounds Of Iron (AREA)
- Paints Or Removers (AREA)
- Magnetic Record Carriers (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野〕
本発明は、高密度記録用磁性酸化鉄粒子粉末として好適
である粒子表面並びに粒子内部に空孔が存在しておらず
、実質的に高密度であって、且つ、粒度が均斉で樹枝状
粒子が混在していない計状磁性酸化鉄粒子粉末の製造法
に関するものである。Detailed Description of the Invention (Industrial Field of Application) The present invention has no pores on the surface or inside of the particles, which are suitable as magnetic iron oxide particles for high-density recording. The present invention relates to a method for producing scale-shaped magnetic iron oxide particles having a uniform density and uniform particle size and not containing dendritic particles.
近年、磁気記録再生用機器の長時間記録化、小型軽量化
が進むにつれて、磁気記録媒体の高性能化、高密度記録
化の要求が高まってきている。BACKGROUND ART In recent years, as magnetic recording and reproducing equipment has become longer recording time and has become smaller and lighter, demands for higher performance and higher density recording of magnetic recording media have been increasing.
磁気記録媒体の高性能化、高記録密度化の為には、残留
磁束密度Ｂｒの向上が必要である。磁気記録媒体の残留
磁束密度Ｂｒは、磁性酸化鉄粒子粉末のビークル中での
分散性、塗膜中での配向性及び充填性に依存している。In order to improve the performance and recording density of magnetic recording media, it is necessary to improve the residual magnetic flux density Br. The residual magnetic flux density Br of the magnetic recording medium depends on the dispersibility of the magnetic iron oxide particles in the vehicle, the orientation and filling properties in the coating film.
そして、ビークル中での分散性、塗膜中での配向性及び
充填性を向上させるためには、ビークル中に分散させる
磁性酸化鉄粒子粉末の粒子表面並びに粒子内部に空孔が
存在しておらず実質的に高密度であって、且つ、粒度が
均斉で樹枝状粒子が混在していない粒子が要求される。In order to improve the dispersibility in the vehicle, the orientation and filling properties in the coating film, it is necessary to prevent the presence of pores on the surface and inside of the magnetic iron oxide particles to be dispersed in the vehicle. Particles are required to have substantially high density, uniform particle size, and no dendritic particles.
現在、磁気記録用磁性粒子粉末として主に針状晶マグネ
タイト粒子粉末または、針状晶マグヘマイト粒子粉末が
用いられている。これらは一般に、第一鉄塩水溶液とア
ルカリとを反応させて得られる水酸化第一鉄粒子を含む
ｐＨｌ１以上のコロイド水溶液を空気酸化しく通常、「
湿式反応」と呼ばれている。）で得られる針状α−Ｆｅ
ｏｏＨ粒子を、空気中３００°Ｃ付近で加熱、脱水して
ヘマタイト粒子となし、更に、水素等還元性ガス中３０
０〜４００℃で還元して針状マグネタイト粒子とし、ま
たは次いでこれを、空気中２００〜３００°Ｃで酸化し
て針状マグヘマイト粒子とすることにより得られている
。Currently, acicular magnetite particles or acicular maghemite particles are mainly used as magnetic particles for magnetic recording. These methods generally involve air oxidation of a colloidal aqueous solution containing ferrous hydroxide particles obtained by reacting a ferrous salt aqueous solution with an alkali and having a pH of 1 or more.
It is called "wet reaction". ) Acicular α-Fe obtained by
The ooH particles are heated and dehydrated in air at around 300°C to form hematite particles, and then heated in a reducing gas such as hydrogen at 30°C.
It is obtained by reducing it to acicular magnetite particles at 0 to 400°C, or by oxidizing it in air at 200 to 300°C to form acicular maghemite particles.
粒子表面並びに粒子内部に空孔が存在しておらず実質的
に高密度であって、且つ、粒度が均斉で樹枝状粒子が混
在していない磁性酸化鉄粒子粉末は、現在量も要求され
ているところであるが、出発原料である針状ゲータイト
粒子を製造する前述の公知方法により得られた粒子粉末
は、樹枝状粒子が混在しており、また粒度から言えば、
均斉な粒度を有した粒子であるとは言い難く、咳針状ゲ
ータイト粒子を出発原料として用い、還元、酸化して得
られた磁性酸化鉄粒子粉末もまた、樹枝状粒子が混在し
ており、また粒度から言えば、均斉な粒度を有した粒子
であるとは言い難いものである。There is a current demand for magnetic iron oxide particle powder that has no pores on the particle surface or inside the particle, has a substantially high density, has a uniform particle size, and does not contain dendritic particles. However, the particle powder obtained by the above-mentioned known method for producing acicular goethite particles as a starting material contains dendritic particles, and in terms of particle size,
It is difficult to say that the particles have a uniform particle size, and the magnetic iron oxide particles obtained by reducing and oxidizing needle-like goethite particles as a starting material also contain dendritic particles. Furthermore, in terms of particle size, it is difficult to say that the particles have a uniform particle size.
また、このゲータイト粒子粉末を出発原料として常法に
より磁性酸化鉄粒子粉末を得た場合、ゲータイト粒子を
加熱脱水して得られるヘマタイト粒子は脱水により、粒
子表面並びに粒子内部に多数の空孔を生じ、次いで、該
ヘマタイト粒子を還元、又は、必要により更に酸化して
得られるマグネイト粒子又はマグヘマイト粒子もまた粒
子表面並びに粒子内部に多数の空孔が分布していること
が観察される。In addition, when magnetic iron oxide particles are obtained using the goethite particles as a starting material by a conventional method, the hematite particles obtained by heating and dehydrating the goethite particles have many pores on the particle surface and inside the particles due to dehydration. Then, it is observed that the magnetite particles or maghemite particles obtained by reducing or further oxidizing the hematite particles also have a large number of pores distributed on the particle surface and inside the particle.
このように、粒子表面並びに粒子内部に多数の空孔を有
する磁性酸化鉄粒子粉末は、ビークル中での分散が悪い
ものである。As described above, magnetic iron oxide particles having a large number of pores on the particle surface and inside the particles have poor dispersion in a vehicle.
磁性酸化鉄粒子の粒子表面並びに粒子内部に発生した空
孔をなくする試みは、例えば特公昭３８−２６１５６号
公報及び粉体および粉末冶金協会昭和４３年度春季大会
講演概要集２−６に記載の通り、従来からなされてはい
るが、いずれの方法も、粒子表面並びに粒子内部に発生
した空孔をなくする為に高温で加熱する必要があり、そ
の結果、粒子及び粒子相互間で焼結が生起し、これを還
元、酸化して得られた磁性酸化鉄粒子粉末は、磁性塗料
を製造スル際ノビ−クル中への分散が悪くなるという欠
点があった。Attempts to eliminate pores generated on the surface and inside of magnetic iron oxide particles have been made, for example, as described in Japanese Patent Publication No. 38-26156 and 2-6 of the Abstracts of Presentations at the 1960 Spring Conference of the Powder and Powder Metallurgy Association. Both methods require heating at high temperatures to eliminate pores generated on the particle surface and inside the particles, and as a result, sintering occurs between the particles and between the particles. The magnetic iron oxide particles obtained by reducing and oxidizing the magnetic iron oxide particles have a disadvantage in that they are difficult to disperse into the novehicle during production of the magnetic paint.
一方、磁性酸化鉄粒子の粒子表面並びに粒子内部に一旦
発生した空孔をなくする方法ではなく、粒子表面並びに
粒子内部に空孔のない粒子を出発原料として磁性酸化鉄
粒子を得る方法も試みられている。On the other hand, instead of the method of eliminating the pores once generated on the particle surface and inside of the magnetic iron oxide particles, a method of obtaining magnetic iron oxide particles using particles without pores on the particle surface and inside the particles as a starting material has also been attempted. ing.
この方法は、例えば、特公昭５５−２２４１６号公報、
特公昭５５−４６９４号公報、特開昭５７−９２５２７
号公報及び特開昭５１−８１９３号公報に記載のように
水溶液中から直接針状晶へマクイト粒子を生成させ、該
針状晶へマクイト粒子を出発原料として還元、酸化する
ことにより針状晶磁性酸化鉄粒子を得る方法である。This method is disclosed in, for example, Japanese Patent Publication No. 55-22416,
Japanese Patent Publication No. 55-4694, Japanese Patent Publication No. 57-92527
As described in Japanese Patent Application Publication No. 51-8193, maquito particles are directly formed into needle-like crystals from an aqueous solution, and the maquito particles are reduced and oxidized to the needle-like crystals as a starting material to form the needle-like crystals. This is a method for obtaining magnetic iron oxide particles.
即ち、粒子表面並びに粒子内部の空孔は、前述した通り
、針状晶ゲータイト粒子を加熱脱水して針状晶へマクイ
ト粒子とする際の脱水により発生するものであるから、
水溶液中から直接針状晶ヘマタイトを生成させれば、脱
水工程を省略することができ、従って、粒子表面並びに
粒子内部に空孔の全くない針状晶へマクイト粒子を得る
ことができ、該へマクイト粒子を出発原料として還元、
酸化して得られた針状晶磁性酸化鉄粒子もまた粒子表面
並びに粒子内部に空孔が全くないものとなる。That is, as mentioned above, the pores on the particle surface and inside the particles are generated by dehydration when acicular goethite particles are heated and dehydrated to convert them into acicular crystals into maquito particles.
If acicular hematite crystals are directly generated from an aqueous solution, the dehydration step can be omitted, and therefore maquito particles can be obtained as acicular crystals with no pores on the particle surface or inside the particles. Reducing maquito particles as a starting material,
The acicular crystal magnetic iron oxide particles obtained by oxidation also have no pores on the particle surface or inside the particle.
上述したところから明らかな通り、粒子表面並びに粒子
内部に空孔が全く存在しておらず実質的に高密度であっ
て、且つ、粒子が均斉で樹枝状粒子が混在していない計
状磁性酸化鉄粒子粉末を得る為には、粒子が均斉で樹枝
状粒子が混在していない針状ヘマタイト粒子を水溶液中
から直接生成させる方法が強（要望されているのである
。As is clear from the above, there are no pores on the particle surface or inside the particle, and the particle is substantially dense, and the particle is uniform and does not contain dendritic particles. In order to obtain iron particle powder, there is a strong demand for a method in which acicular hematite particles, which are uniform and do not contain dendritic particles, are directly produced from an aqueous solution.
本発明者は、粒度が均斉で樹枝状粒子が混在していない
針状ヘマタイト粒子を水溶液中から直接生成させる方法
について種々検討を重ねた結果、本発明に到達したので
ある。The present inventor has arrived at the present invention as a result of various studies on a method for directly producing acicular hematite particles having a uniform particle size and no dendritic particles mixed therein from an aqueous solution.
即ち、本発明は、β−Ｆｅ００１を含む水懸濁液にアル
カリ性水溶液を添加してｐＨ８以上の水性懸濁液とし、
次いで、該水性懸濁液に塩酸を添加して得られた前記β
−ＦｅＯＯＩＩを含むｐ１１７以下の水性懸濁液に、当
該懸濁液中のＦｅ（２）に対しＰ換算で０．１〜２，０
原子％のリン化合物を添加した後、］００〜１３０°Ｃ
の温度範囲で水熱処理することにより、針状ヘマタイト
粒子を生成させ、該針状ヘマタイト粒子を還元性ガス中
で加熱還元して針状マグネタイト粒子とするか、又は、
更に酸化して針状マグヘマイト粒子とすることよりなる
針状磁性酸化鉄粒子からなる磁性酸化鉄粒子粉末の製造
法である。That is, the present invention adds an alkaline aqueous solution to an aqueous suspension containing β-Fe001 to form an aqueous suspension with a pH of 8 or more,
Next, the above β obtained by adding hydrochloric acid to the aqueous suspension
- In an aqueous suspension containing FeOOII with p117 or less, 0.1 to 2,0 in terms of P is added to Fe(2) in the suspension.
After adding atomic% of phosphorus compound]00-130°C
Acicular hematite particles are generated by hydrothermal treatment in a temperature range of
This is a method for producing magnetic iron oxide particle powder consisting of acicular magnetic iron oxide particles, which is further oxidized to form acicular maghemite particles.
先ず、本発明において最も重要な点は、β−ＦｅＯＯＨ
含む水懸濁液にアルカリ性水溶液を添加してｐＨ８以上
の水性懸濁液とし、次いで、該水性懸濁液に塩酸を添加
して得られた前記β−Ｆｅ００１１を含むｐｌ！７以下
の水性懸濁液に、当該懸濁液中のＦｅ＠に対しＰ換算で
０．１〜２．０原子％のリン化合物を添加した後、１０
０〜１３０℃の温度範囲で水熱処理した場合には、粒子
内部に空孔が存在しておらず、実質的に高密度であって
、且つ、粒度が均斉で樹枝状粒子が混在していない針状
ヘマタイト粒子を水溶液中から直接生成させることがで
き、該針状ヘマタイト粒子を加熱還元して得られる針状
マグネタイト粒子及び必要により更に加熱酸化して得ら
れる針状マグヘマイト粒子もまた、出発原料である針状
へ７タイト粒子の粒子形状を保持継承していることによ
って、粒子内部に空孔が存在しておらず、実質的に高密
度であって、且つ、粒度が均斉で樹枝状粒子が混在して
いない針状粒子であるという事実である。First, the most important point in the present invention is that β-FeOOH
An alkaline aqueous solution is added to an aqueous suspension containing the β-Fe0011 to obtain an aqueous suspension having a pH of 8 or more, and then hydrochloric acid is added to the aqueous suspension. After adding a phosphorus compound of 0.1 to 2.0 atom % in terms of P to Fe@ in the suspension to an aqueous suspension of 7 or less,
When hydrothermally treated at a temperature range of 0 to 130°C, there are no pores inside the particles, the particles are substantially dense, the particle size is uniform, and dendritic particles are not mixed. Acicular hematite particles can be produced directly from an aqueous solution, and acicular magnetite particles obtained by heating and reducing the acicular hematite particles and acicular maghemite particles obtained by further heating and oxidizing the acicular hematite particles if necessary can also be used as starting materials. By retaining and inheriting the particle shape of 7 tight particles to the needle-like shape, there are no pores inside the particles, and the particles are substantially high-density, uniform in particle size, and dendritic particles. This is the fact that they are acicular particles that are not mixed together.
本発明において針状ヘマタイト粒子が生成する理由につ
いて、本発明者は、後出の比較例に示す通り、リン化合
物を添加しない場合には、等方的なヘマタイト粒子が生
成することから、リン化合物が生成するヘマタイト粒子
の粒子形態に関与しているものと考えている。As for the reason why acicular hematite particles are generated in the present invention, the present inventors believe that, as shown in the comparative example below, isotropic hematite particles are generated when a phosphorus compound is not added. We believe that this is related to the particle morphology of the hematite particles produced.
本発明においては、ｐ１１８以との水性懸濁液をｐＨ７
以下の水性懸濁液とする為に使用する酸として塩酸を使
用した場合には、ヘマタイト粒子を生成させることがで
きるが、塩酸以外の酸、例えば、硫酸、酢酸、燐酸等を
使用する場合にはヘマタイト粒子を生成させることがで
きない。In the present invention, an aqueous suspension with pH 7 or higher is used.
When hydrochloric acid is used as the acid used to form the aqueous suspension described below, hematite particles can be generated, but when using acids other than hydrochloric acid, such as sulfuric acid, acetic acid, phosphoric acid, etc. cannot produce hematite particles.
次に、本発明実施にあたっての諸条件について述べる。Next, various conditions for implementing the present invention will be described.
本発明においては、鉄原料としてβ−ＦｅＯＯＨを使用
することが必要である。β−ＦｅＯＯ１ｌは、塩化第二
鉄水溶液を加熱処理して加水分解する方法、塩化第一鉄
水溶液に酸素含有ガスを通気して酸化反応を行う方法等
により得ることができ、不定形、針状、紡錘状等いかな
る粒子形態のものでも使用することができる。In the present invention, it is necessary to use β-FeOOH as the iron raw material. β-FeOO1l can be obtained by a method of heating and hydrolyzing a ferric chloride aqueous solution, a method of conducting an oxidation reaction by passing an oxygen-containing gas through a ferrous chloride aqueous solution, etc. , spindle-shaped, etc. particles can be used.
本発明において、β−ＦｅＯＯＨを含む水懸濁液のｐＨ
は高々６．０程度であり、当該水懸濁液にアルカリ性水
溶液を添加することによりｐＨ８以上とする。In the present invention, the pH of an aqueous suspension containing β-FeOOH
is about 6.0 at most, and the pH is adjusted to 8 or higher by adding an alkaline aqueous solution to the aqueous suspension.
本発明におけるアルカリ性水溶液としては、水酸化ナト
リウム、水酸化カリウム、アンモニア水等を使用するこ
とができる。アルカリ性水溶液添加後の水性懸濁液のｐ
Ｈが８以下の場合には、ヘマタイトとβ−Ｆｅ００Ｈの
混合物が生成する。As the alkaline aqueous solution in the present invention, sodium hydroxide, potassium hydroxide, aqueous ammonia, etc. can be used. p of aqueous suspension after addition of alkaline aqueous solution
When H is 8 or less, a mixture of hematite and β-Fe00H is produced.
本発明において、ｐＨ８以上の水性懸濁液をρ１１７以
下の水性懸濁液にする為には、塩酸を使用することが必
要である。塩酸添加後の水性懸濁液のｐＨが７以上であ
る場合には、１００〜１３０℃の温度領域においてはβ
−ＦｅＯＯ１ｌが安定して生成する為ヘマタイト粒子が
生成しない。In the present invention, it is necessary to use hydrochloric acid in order to turn an aqueous suspension with a pH of 8 or more into an aqueous suspension with a pH of 117 or less. If the pH of the aqueous suspension after addition of hydrochloric acid is 7 or more, β
- Hematite particles are not generated because 1l of FeOO is generated stably.
本発明においては、β−Ｆｅ００１１を含む水懸濁液の
濃度が１．０ ｍｏｌ／ｊ！程度の高濃度であってもヘ
マタイト粒子を生成することが可能である。１．０ ＋
＊ｏｌ／１以上の場合にもヘマタイト粒子は生成するが
、粒度が不均斉となる。In the present invention, the concentration of the aqueous suspension containing β-Fe0011 is 1.0 mol/j! It is possible to produce hematite particles even at moderately high concentrations. 1.0 +
*Although hematite particles are generated when ol/1 or more, the particle size becomes asymmetric.
本発明におけるリン化合物としては、メタリン酸、次亜
リン酸、亜リン酸、正リン酸、ピロリン酸及びこれ等の
基環無機のリン化合物を用いることができる。As the phosphorus compound in the present invention, metaphosphoric acid, hypophosphorous acid, phosphorous acid, orthophosphoric acid, pyrophosphoric acid, and cyclic inorganic phosphorus compounds such as these can be used.
リン化合物の添加量は、懸濁液中のＦｅ＠に対し、Ｐ換
算で０．１〜２．０原子％である。０．１原子％以下で
ある場合には、本発明の目的とする針状ヘマタイト粒子
を得ることができない。２．０原子％以上である場合に
も、針状ヘマタイトが生成するが、反応に長時間を要す
る。The amount of the phosphorus compound added is 0.1 to 2.0 at% in terms of P based on Fe@ in the suspension. If it is less than 0.1 atomic %, the acicular hematite particles that are the object of the present invention cannot be obtained. If the content is 2.0 at % or more, acicular hematite is produced, but the reaction takes a long time.
本発明における反応温度は、１００〜１３０℃である。The reaction temperature in the present invention is 100 to 130°C.
１００℃以下である場合には、β−Ｆｅ００Ｈの溶解が
十分に進行しない為ヘマタイト粒子が生成しない。１３
０°Ｃ以上である場合にもヘマタイト粒子は生成するが
、高圧容器等特殊な装置を必要とする為、工業的、経済
的ではない。If the temperature is 100° C. or lower, the dissolution of β-Fe00H does not proceed sufficiently, so that hematite particles are not generated. 13
Although hematite particles are generated when the temperature is 0°C or higher, this is not industrially or economically viable because special equipment such as a high-pressure container is required.
本発明における還元性ガス中における加熱還元処理及び
酸化処理は常法により行うことができる。The heating reduction treatment and oxidation treatment in a reducing gas in the present invention can be performed by conventional methods.
また、出発原料であるヘマタイト粒子は、加熱処理に先
立って通常行われるＳｔ、 ＡＩ、 Ｐ化合物等の焼結
防止効果を有する物質によってあらかじめ被覆処理して
おくことにより、より分散性の優れた磁性酸化鉄粒子粉
末を得ることができる。In addition, the hematite particles, which are the starting material, are coated in advance with a substance that has a sintering prevention effect, such as St, AI, or P compounds, which is usually carried out prior to heat treatment, to create magnetic properties with better dispersibility. Iron oxide particle powder can be obtained.
次に、実施例並びに比較例により本発明を説明する。 Next, the present invention will be explained with reference to Examples and Comparative Examples.
尚、以下の実施例における粒子の平均径は、電子顕微鏡
写真から測定した数値の平均値であり、比表面積はＢＥ
Ｔ法により測定した値である。In addition, the average diameter of particles in the following examples is the average value of numerical values measured from electron micrographs, and the specific surface area is BE
This is a value measured by the T method.
実施例１
Ｏ，４ｍｏｌ／ｊ！のβ−Ｆｅ００８粒子（比表面積５
Ｆｌｒｒｆ／ｇ）を含むｐＨ５，５の水懸濁液５００ｔ
ａ ＩｌにＮａＯＨ水溶液を添加してｐＨ９，０の水性
懸濁液を得た。Example 1 O,4mol/j! β-Fe008 particles (specific surface area 5
500 t of pH 5.5 water suspension containing Flrrf/g)
a NaOH aqueous solution was added to Il to obtain an aqueous suspension with pH 9.0.
ト記水性懸濁液にＩＣ！水溶液を添加して得られたβ−
Ｆｅ００８粒子を含むｐＨ２，０の水性懸濁液に、正リ
ンＰａ Ｏ，２０ｇ （Ｆｅ＠に対しＰ換算で１．０原
子％に該当する。）を添加した後、密閉容器中に入れ、
１２５°Ｃで１５時間水熱処理して赤褐色沈澱を生成さ
せた。赤褐色沈澱を水洗、濾過、乾燥して得られた粒子
粉末は、図１に示すＸ線回折に示す通り、ヘマタイトで
あり、図２に示す電子顕微鏡写真（ｘ ２０．００Ｇ）
から明らかな通り、平均粒子径が０．８μ−である実質
的に高密度な針状粒子であり、粒度が均斉で樹枝状粒子
が混在しておらず、且つ、個々の粒子が独立した粒子で
あった。IC for aqueous suspension! β- obtained by adding aqueous solution
After adding 20 g of orthophosphorus Pa O (corresponding to 1.0 atomic % in terms of P to Fe@) to an aqueous suspension containing Fe008 particles at pH 2.0, it was placed in a closed container,
Hydrothermal treatment at 125°C for 15 hours produced a reddish brown precipitate. The particles obtained by washing the reddish brown precipitate with water, filtration, and drying were hematite as shown in the X-ray diffraction shown in Figure 1, and the electron micrograph (x 20.00G) shown in Figure 2.
As is clear from the above, the particles are substantially dense acicular particles with an average particle size of 0.8 μ-, the particle size is uniform, dendritic particles are not mixed, and each particle is independent. Met.
上記へ、マタイト粒子粉末７０ｇをＩＩ！、のレトルト
還元容器中に投入し、駆動回転させなから１！□ガスを
毎分１ｉの割合で通気し、還元温度３５０°Ｃで還元し
てマグネタイト粒子粉末を得た。得られたマグネタイト
粒子粉末は、電子顕微鏡観察の結果、平均粒子径が０．
７μｍである実質的に高密度な針状粒子であり、粒度が
均斉で樹枝状粒子が混在しておらず、且つ、個々の粒子
が独立した粒子であった。また、磁気測定の結果、保磁
力Ｈｃは３０４０ｅ、飽和磁化σ３は８９．２ ｅｍｕ
／ｇであった。To the above, add 70g of matite particle powder II! , put it in the retort reduction container and drive it to rotate.1! □Gas was passed through the reactor at a rate of 1 i per minute, and the material was reduced at a reduction temperature of 350°C to obtain magnetite particle powder. As a result of electron microscopic observation, the obtained magnetite particles had an average particle diameter of 0.
The particles were acicular particles with a substantially high density of 7 μm, the particle size was uniform, dendritic particles were not mixed, and each particle was an independent particle. In addition, as a result of magnetic measurement, the coercive force Hc is 3040e, and the saturation magnetization σ3 is 89.2 emu.
/g.
と記マグネタイト粒子粉末７０ｇを空気中３００°Ｃで
６０分間酸化してマグヘマイト粒子粉末を得た。Magnetite particles (70 g) were oxidized in air at 300° C. for 60 minutes to obtain maghemite particles.
得られたマグヘマイト粒子粉末は、電子顕微鏡観察の結
果、平均粒子径０．７μｍである実質的に高密度な針状
粒子であり、粒度が均斉で樹枝状粒子が混在しておらず
、且つ、個々の粒子が独立した粒子であった。また、磁
気測定の結果、保磁力＋１ｃは２９５０ｅ、飽和磁化σ
ｓは８２．３ ｅｍｕ／ｇであった。As a result of electron microscopy observation, the obtained maghemite particles were found to be substantially high-density acicular particles with an average particle diameter of 0.7 μm, the particle size was uniform, no dendritic particles were mixed, and Each particle was an independent particle. Also, as a result of magnetic measurement, the coercive force +1c is 2950e, and the saturation magnetization σ
s was 82.3 emu/g.
実施例２
０．５ ｍｏｌ／ｊ！のβ−Ｆｅ００８粒子（比表面積
＋１Ｏｎ？／ｇ）を含むｐｏｓ、ｏの水懸濁液５００ｍ
ｌにＮＩｌ、ＯＨ水溶液を添加してｐＨ８，５の水性
懸濁液を得た。Example 2 0.5 mol/j! 500 m of water suspension of pos, o containing β-Fe008 particles (specific surface area +1 On?/g)
An aqueous solution of NIl and OH was added to the solution to obtain an aqueous suspension having a pH of 8.5.
ト記水性懸濁液にＨＣＩ水溶液を添加して得られたβ−
Ｆｅ００１１粒子を含むｐｕｔ、ｓの水性懸濁液に、正
リン酸０．１２５８（Ｆｅ ＠に対しＰ換算で０．５原
子％に該当する。）を添加した後、密閉容器中に入れ、
１２５℃で１５時間水熱処理して赤褐色沈澱を生成させ
た。赤褐色沈澱を水洗、濾過、乾燥して得られた粒子粉
末は、Ｘ線回折の結果ヘマタイトであり、図５に示す電
子顕微鏡写真（ｘ ２０．０００）から明らかな通り、
平均粒子径が０．５μ−である実質的に高密度な針状粒
子であり、粒度が均斉で樹枝状粒子が混在しておらず、
且つ、個々の粒子が独立した粒子であった。β- obtained by adding HCI aqueous solution to the above aqueous suspension
After adding 0.1258 atomic % of orthophosphoric acid (corresponding to 0.5 atomic % in terms of P to Fe@) to an aqueous suspension of put, s containing Fe0011 particles, put it in a closed container,
Hydrothermal treatment at 125° C. for 15 hours produced a reddish brown precipitate. The particles obtained by washing the reddish-brown precipitate with water, filtering, and drying were found to be hematite as a result of X-ray diffraction, as is clear from the electron micrograph (x 20,000) shown in Figure 5.
Substantially dense acicular particles with an average particle diameter of 0.5 μ-, uniform particle size, and no dendritic particles mixed.
Moreover, each particle was an independent particle.
上記ヘマタイト粒子粉末７０ｇを１１のレトルト還元容
器中に投入し、駆動回転させなからＨ！ガスを毎分１１
の割合で通気し、還元温度３５０℃で還元してマグネタ
イト粒子粉末を得た。得られたマグネタイト粒子粉末は
、電子顕微鏡観察の結果、平均粒子径が０．４μｍであ
る実質的に高密度な針状粒子であり、粒度が均斉で樹枝
状粒子が混在しておらず、且つ、個々の粒子が独立した
粒子であった。また、磁気測定の結果、保磁力Ｈｃは２
５５０ｓ、飽和磁化σＳは８８．８ ｅｍｕ／ｇであっ
た。Put 70g of the above hematite particle powder into the retort reduction container No. 11, drive and rotate it, and then H! 11 gas per minute
The mixture was aerated at a rate of 350° C. and reduced at a reduction temperature of 350° C. to obtain magnetite particle powder. As a result of electron microscopy observation, the obtained magnetite particles were found to be substantially dense acicular particles with an average particle diameter of 0.4 μm, uniform particle size, no dendritic particles mixed, and , each particle was an independent particle. Also, as a result of magnetic measurement, the coercive force Hc is 2
550 s, the saturation magnetization σS was 88.8 emu/g.
ト記マグネタイト粒子粉末７０ｇを空気中３００°Ｃで
６０分間酸化してマグヘマイト粒子粉末を得た。Magnetite particles (70 g) were oxidized in air at 300° C. for 60 minutes to obtain maghemite particles.
得られたマグヘマイト粒子粉末は、電子顕微鏡観察の結
果、平均粒子径０．４μｍである実質的に高密度な針状
粒子であり、粒度が均斉で樹枝状粒子が混在しておらず
、且つ、個々の粒子が独立した粒子であった。また、磁
気測定の結果、保磁力１１ｃは２３１０ｅ、 ｉｉｉ！
和磁化σｓはｆｌｏ、２ ｅｍｕ／ｇであった。As a result of electron microscopic observation, the obtained maghemite particles were found to be substantially high-density acicular particles with an average particle size of 0.4 μm, the particle size was uniform, no dendritic particles were mixed, and, Each particle was an independent particle. Also, as a result of magnetic measurement, the coercive force 11c is 2310e, iii!
The sum magnetization σs was flo, 2 emu/g.
比較例１
正リン酸を添加しなかった以外は、実施例１と同様に水
熱処理して赤褐色沈澱を生成させた。Comparative Example 1 A reddish-brown precipitate was produced by hydrothermal treatment in the same manner as in Example 1, except that orthophosphoric acid was not added.
赤褐色沈澱を水洗、濾過、乾燥して得られた粒子粉末は
、図４に示すＸ線回折及び図５に示す電子顕微鏡写真（
Ｘ２０，０００）から明らかな通り、平均粒径が０．３
μ−の等方的粒子であった。The particles obtained by washing the reddish-brown precipitate with water, filtration, and drying showed the X-ray diffraction shown in Figure 4 and the electron micrograph shown in Figure 5 (
As is clear from X20,000), the average particle size is 0.3
They were μ-isotropic particles.
比較例２
０．２ ｍｏ１／ｆｆｉのβ−Ｆｅ００１１粒子（比表
面積１８０ ｒｒｒ／ｇ）を含むｐＨ，７の水懸濁液５
００ｓ ｅをＭａｉｌ水溶液及びＭＣｌ水溶液を用いて
ｐＨ３１１整することなく、そのまま密閉容器中に入れ
、実施例１と同様に水熱処理して黄褐色沈澱を生成させ
た。Comparative Example 2 Water suspension 5 at pH 7 containing 0.2 mo1/ffi β-Fe0011 particles (specific surface area 180 rrr/g)
00se was put into a sealed container as it was without adjusting the pH to 311 using a Mail aqueous solution and an MCl aqueous solution, and was hydrothermally treated in the same manner as in Example 1 to generate a yellow brown precipitate.
黄褐色沈澱を水洗、ｐ遇、乾燥して得られた粒子粉末は
、Ｘ線回折の結果及び図６に示す電子顕微鏡写％ （ｘ
２０．００Ｇ）から明らかな通り、β−ＦｅＯＯＨの
ままであった。The particles obtained by washing the yellowish brown precipitate with water, plating, and drying showed the results of X-ray diffraction and the electron micrograph shown in Figure 6 (x
20.00G), it remained β-FeOOH.
比較例３
ＮａＯ）ｌ水溶液を添加してｐＨ６，８の水性懸濁液と
した以外は実施例１と同様に水熱処理して茶褐色沈澱を
生成させた。茶褐色沈澱を水洗、枦遇、乾燥して得られ
た粒子粉末は、ＸＩＪ１回折の結果及び図７の電子顕微
鏡写真（ｘ２０．０００）から明らかな通り、β−Ｆｅ
００Ｈとヘマタイトの混合物であった。Comparative Example 3 A brown precipitate was produced by hydrothermal treatment in the same manner as in Example 1, except that an aqueous NaO)l solution was added to obtain an aqueous suspension with a pH of 6.8. As is clear from the results of XIJ1 diffraction and the electron micrograph (x20,000) in FIG.
It was a mixture of 00H and hematite.
比較例４
ＭＣｌ水溶液を添加してβ−ＦｅＯＯＨ含むｐＨ７，５
の水性懸濁液とした以外は、実施例１と同様に水熱処理
して黄褐色沈澱を生成させた。黄褐色沈澱を水洗、枦遇
、乾燥して得られた粒子粉末は、Ｘ線 。Comparative Example 4 pH 7.5 containing β-FeOOH by adding MCl aqueous solution
A yellowish brown precipitate was produced by hydrothermal treatment in the same manner as in Example 1, except that an aqueous suspension was prepared. The yellow-brown precipitate was washed with water, dried, and the resulting powder particles were exposed to X-rays.
回折の結果及び図８に示す電子顕微鏡写真（Ｘ ５０゜
０００）から明らかな通り、β−ＦｅＯＯＨのままであ
った。As is clear from the diffraction results and the electron micrograph (X 50°000) shown in FIG. 8, it remained β-FeOOH.
比較例５
水熱処理の温度を９５℃とした以外は、実施例１と同様
にして黄褐色沈澱を生成させた。黄褐色沈澱を水洗、濾
過、乾燥して得られた粒子粉末は、図９に示すＸ線回折
及び図１０に示す電子ｗ４微繞写真（ｘ５０，０００）
から明らかな通り、β−ＦｅＯＯＨのままであった。Comparative Example 5 A yellow brown precipitate was produced in the same manner as in Example 1, except that the temperature of the hydrothermal treatment was 95°C. The particles obtained by washing the yellow brown precipitate with water, filtering, and drying showed the X-ray diffraction shown in Figure 9 and the electron W4 micrograph (x50,000) shown in Figure 10.
As is clear from this, it remained β-FeOOH.
本発明における計状磁性酸化鉄粒子粉末の製造法によれ
ば、前出実施例に示した通り、粒子表面並びに粒子内部
に空孔が存在しておらず実質的に高密度であって、且つ
、粒度が均斉で樹枝状粒子が混在していない針状磁性酸
化鉄粒子からなる計状磁性酸化鉄粒子粉末を得ることが
できるので、高性能、高密度記録用磁性酸化鉄粒子粉末
とじて好適なものである。According to the method for producing the scale-shaped magnetic iron oxide particles of the present invention, as shown in the previous example, the particles have substantially high density with no pores on the particle surface or inside the particles, and Since it is possible to obtain a scale-shaped magnetic iron oxide particle powder consisting of acicular magnetic iron oxide particles with uniform particle size and no dendritic particles, it is suitable as a magnetic iron oxide particle powder for high-performance, high-density recording. It is something.
図１、図４及び図９はいずれもＸ線回折図であり、図４
は実施例１で得られたヘマタイト粒子粉末、図８は、比
較例１で得られたヘマタイト粒子粉末、図９は比較例５
で得られたβ−ＰｅＯＯＩ（粒子粉末である。
図２、図３、図５乃至図８及び図１０は、いずれも電子
顕微鏡写真であり、図２、図３及び図５はそれぞれ一実
施例１、実施例２及び比較例］で得られた針状ヘマタイ
ト粒子粉末、図６、図８及び図１０はそれぞれ、比較例
２及び比較例４及び比較例５で得られたβ−ＦｅＯＯＨ
粒子粉末、図７は、ヘマタイトとβ−Ｆｅ００Ｈとの混
合物粒子粉末である。Figures 1, 4, and 9 are all X-ray diffraction diagrams, and Figure 4
8 is the hematite particle powder obtained in Example 1, FIG. 8 is the hematite particle powder obtained in Comparative Example 1, and FIG. 9 is the hematite particle powder obtained in Comparative Example 5.
β-PeOOI (particle powder) obtained in . 1, Example 2 and Comparative Example], FIGS. 6, 8 and 10 are β-FeOOH obtained in Comparative Example 2, Comparative Example 4 and Comparative Example 5, respectively.
The particle powder shown in FIG. 7 is a mixture particle powder of hematite and β-Fe00H.
Claims (1)
液を添加してｐＨ８以上の水性懸濁液とし、次いで、該
水性懸濁液に塩酸を添加して得られた前記β−ＦｅＯＯ
Ｈ含むｐＨ７以下の水性懸濁液に、当該懸濁液中のＦｅ
（III）に対しＰ換算で０．１〜２．０原子％のリン化
合物を添加した後、１００〜１３０℃の温度範囲で水熱
処理することにより、針状ヘマタイト粒子を生成させ、
該針状ヘマタイト粒子を還元性ガス中で加熱還元して、
計状マグネタイト粒子とするか、又は、更に酸化して、
針状マグヘマイト粒子とすることを特徴とする計状磁性
酸化鉄粒子粉末の製造法。(1) The β-FeOOH obtained by adding an alkaline aqueous solution to an aqueous suspension containing β-FeOOH to obtain an aqueous suspension with a pH of 8 or higher, and then adding hydrochloric acid to the aqueous suspension.
Fe in the suspension is added to an aqueous suspension containing H at pH 7 or less.
After adding 0.1 to 2.0 atom % of a phosphorus compound in terms of P to (III), hydrothermal treatment is performed in a temperature range of 100 to 130°C to generate acicular hematite particles,
The acicular hematite particles are heated and reduced in a reducing gas,
into scale-shaped magnetite particles, or further oxidize,
A method for producing a scale-shaped magnetic iron oxide particle powder characterized by forming needle-shaped maghemite particles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63048386A JPH01222409A (en) | 1988-02-29 | 1988-02-29 | Manufacture of needle-like magnetic iron-oxide particle and powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63048386A JPH01222409A (en) | 1988-02-29 | 1988-02-29 | Manufacture of needle-like magnetic iron-oxide particle and powder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01222409A true JPH01222409A (en) | 1989-09-05 |
Family
ID=12801865
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63048386A Pending JPH01222409A (en) | 1988-02-29 | 1988-02-29 | Manufacture of needle-like magnetic iron-oxide particle and powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01222409A (en) |
-
1988
- 1988-02-29 JP JP63048386A patent/JPH01222409A/en active Pending
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