JPH0755828B2 - Magnetic particle powder and method for producing the same - Google Patents
Magnetic particle powder and method for producing the sameInfo
- Publication number
- JPH0755828B2 JPH0755828B2 JP62215564A JP21556487A JPH0755828B2 JP H0755828 B2 JPH0755828 B2 JP H0755828B2 JP 62215564 A JP62215564 A JP 62215564A JP 21556487 A JP21556487 A JP 21556487A JP H0755828 B2 JPH0755828 B2 JP H0755828B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- particles
- hydrated alumina
- particle powder
- suspension
- 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 - Fee Related
Links
- 239000006249 magnetic particle Substances 0.000 title claims description 60
- 239000000843 powder Substances 0.000 title claims description 47
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 239000002245 particle Substances 0.000 claims description 82
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 37
- 239000000725 suspension Substances 0.000 claims description 28
- 150000001875 compounds Chemical class 0.000 claims description 25
- 229910052782 aluminium Inorganic materials 0.000 claims description 15
- 229910052710 silicon Inorganic materials 0.000 claims description 15
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical group O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 claims description 9
- 239000002253 acid Substances 0.000 claims description 7
- 239000007864 aqueous solution Substances 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 7
- 239000003513 alkali Substances 0.000 claims description 6
- 238000000151 deposition Methods 0.000 claims description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 21
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 14
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 12
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 12
- 229910001566 austenite Inorganic materials 0.000 description 12
- 239000011248 coating agent Substances 0.000 description 9
- 238000000576 coating method Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 229910004298 SiO 2 Inorganic materials 0.000 description 7
- 230000005415 magnetization Effects 0.000 description 7
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- 230000005389 magnetism Effects 0.000 description 6
- 239000003973 paint Substances 0.000 description 6
- 239000002244 precipitate Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 229910000859 α-Fe Inorganic materials 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 230000004907 flux Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 238000002441 X-ray diffraction Methods 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 239000010419 fine particle Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 239000006247 magnetic powder Substances 0.000 description 2
- 239000012046 mixed solvent Substances 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 229920001225 polyester resin Polymers 0.000 description 2
- 239000004645 polyester resin Substances 0.000 description 2
- 235000019353 potassium silicate Nutrition 0.000 description 2
- 229910001388 sodium aluminate Inorganic materials 0.000 description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 1
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 1
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 1
- 239000004111 Potassium silicate Substances 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- 229920002433 Vinyl chloride-vinyl acetate copolymer Polymers 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 150000004645 aluminates Chemical class 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- 239000008119 colloidal silica Substances 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000010335 hydrothermal treatment Methods 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 1
- 229910052913 potassium silicate Inorganic materials 0.000 description 1
- KVOIJEARBNBHHP-UHFFFAOYSA-N potassium;oxido(oxo)alumane Chemical compound [K+].[O-][Al]=O KVOIJEARBNBHHP-UHFFFAOYSA-N 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 229920002803 thermoplastic polyurethane Polymers 0.000 description 1
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、高密度記録用磁性粒子粉末として好適な分散
性に優れた磁性粒子粉末及びその製造法に係るものであ
る。TECHNICAL FIELD The present invention relates to a magnetic particle powder having excellent dispersibility, which is suitable as a magnetic particle powder for high density recording, and a method for producing the same.
近年、磁気記録再生用機器等の小型軽量化が進むにつれ
て磁気テープ、磁気ディスク等の磁気記録媒体に対する
高性能化、高密度記録化の要求が高まってきている。In recent years, as the size and weight of magnetic recording / reproducing devices have been reduced, there has been an increasing demand for high performance and high density recording of magnetic recording media such as magnetic tapes and magnetic disks.
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 the recording density of the magnetic recording medium, 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 particle powder in the vehicle, the orientation in the coating film, and the filling property.
磁性粒子粉末の分散性の改良は、従来から種々試みられ
ており、例えば、特開昭55-83207号公報、特開昭57-569
04号公報、特開昭61-63921号公報、特開昭60-217529号
公報、特開昭62-89226号公報、特開昭58-60506号公報、
特開昭58-161725号公報及び特開昭59-23505号公報等に
記載されている通り、磁性粒子粉末の粒子表面をSi化合
物やAl化合物で被覆することにより粒子表面を改質する
方法がある。Various attempts have been made to improve the dispersibility of magnetic particle powders, for example, JP-A-55-83207 and JP-A-57-569.
JP 04, JP 61-63921 JP, JP 60-217529 JP, JP 62-89226 JP, JP 58-60506 JP,
As described in JP-A-58-161725 and JP-A-59-23505, there is a method of modifying the particle surface of a magnetic particle powder by coating the particle surface with a Si compound or an Al compound. is there.
分散性に優れた磁性粒子粉末は、現在最も要求されてい
るところであるが、前述した公知方法による場合には未
だ分散性に優れた粒子とは言い難いものである。公知方
法において未だ分散性に優れた粒子が得られていない理
由は、例えば「磁気記録材料研究者の立場からみた磁性
ペイント」（粉体粉末冶金「第７回フェライト夏季セミ
ナー講演概要集」（昭和52年）第14〜16頁）の第16頁の
「一般に高度の分散を得ることは通常の非磁性顔料の場
合でもかなり難しい問題である。まして、磁性粉の場合
は粒子間の磁気的相互作用のために現象をさらに複雑な
ものにしている。」なる記載の通り、磁性粒子粉末は、
磁性による相互作用により凝集体を形成している為、凝
集体のままで表面被覆されていることに起因している。Magnetic particle powders having excellent dispersibility are currently most demanded, but it is hard to say that they are particles having excellent dispersibility by the above-mentioned known method. The reason why particles with excellent dispersibility have not yet been obtained by the known method is, for example, "Magnetic paint from the viewpoint of researchers of magnetic recording materials" (powder powder metallurgy "7th Ferrite Summer Seminar Lecture Summary") (52) pp. 14-16), p. 16, "In general, obtaining a high degree of dispersion is a fairly difficult problem even in the case of ordinary non-magnetic pigments. The effect further complicates the phenomenon. "
This is because the aggregates are formed by the interaction due to magnetism, and thus the surface is covered with the aggregates as they are.
特に、板面に対し垂直方向に磁化容易軸を有する六法晶
系フェライト粒子粉末の場合には、磁性による相互作用
により粒子相互が強固に凝集し、単に機械的処理のみに
よっては凝集粒子を個々の粒子に分離させることは困難
である。In particular, in the case of hexagonal ferrite particle powder having an easy axis of magnetization in the direction perpendicular to the plate surface, the particles are strongly aggregated by the interaction of magnetism, and the aggregated particles are individually separated by only mechanical treatment. Separation into particles is difficult.
そこで、より分散性に優れた磁性粒子粉末を得るべく、
磁性粒子粉末の粒子表面を被覆処理する為の技術手段の
確立が強く要望されている。Therefore, in order to obtain a magnetic particle powder having more excellent dispersibility,
There is a strong demand for establishment of a technical means for coating the particle surface of magnetic particle powder.
本発明者は、より分散性に優れた磁性粒子粉末を得るべ
く、磁性粒子粉末の粒子表面を被覆処理する方法につい
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 reached the present invention as a result of various studies on a method of coating the particle surface of the magnetic particle powder in order to obtain a magnetic particle powder having more excellent dispersibility.
即ち、本発明は、磁性粒子表面と当該粒子表面を被覆し
ているAl又はSi若しくはAl及びSiのいずれかを含む酸化
物層或いは水酸化物層との間に、ベーマイト構造を有す
る水和アルミナ粒子が存在している磁性粒子からなる磁
性粒子粉末及び磁性粒子とベーマイト構造を有する水和
アルミナ粒子とを含むpH9以上又は４以下の混合懸濁液
に酸又はアルカリ水溶液を添加してpH6.5〜8.5に調整す
ることにより、前記磁性粒子の粒子表面に前記水和アル
ミナ粒子を沈着させ、次いで、該水和アルミナ粒子が沈
着している磁性粒子を含む懸濁液にアルカリ水溶液を添
加してpH10以上の懸濁液とした後、該懸濁液にAlを含む
化合物又はSiを含む化合物若しくは当該両化合物を添加
し、次いで酸を添加してpH6.5〜8.5に調整することによ
り、前記水和アルミナ粒子が沈着している磁性粒子の粒
子表面にAl又はSi若しくはAl及びSiのいずれかを含む酸
化物層或いは水酸化物層を生成させることからなる磁性
粒子粉末の製造法である。That is, the present invention is a hydrated alumina having a boehmite structure between a magnetic particle surface and an oxide layer or a hydroxide layer containing Al or Si or Al and Si which coats the particle surface. PH 6.5 by adding an acid or alkali aqueous solution to a mixed suspension of pH 9 or more or 4 or less containing magnetic particle powder consisting of magnetic particles in which particles are present and magnetic particles and hydrated alumina particles having a boehmite structure By adjusting to ~ 8.5, the hydrated alumina particles are deposited on the surface of the magnetic particles, and then an aqueous alkali solution is added to the suspension containing the magnetic particles on which the hydrated alumina particles are deposited. After the suspension having a pH of 10 or more, a compound containing Al or a compound containing Si or both compounds is added to the suspension, and then an acid is added to adjust the pH to 6.5 to 8.5. Hydrated alumina particles settle A method for producing magnetic particles consists in generating the oxide layer or hydroxide layer containing either Al or Si or Al and Si on the particle surfaces of the magnetic particles are.
先ず、本発明において最も重要な点は、磁性粒子の粒子
表面をAl又Si若しくはAl及びSiのいずれかを含む酸化物
或いは水酸化物で被覆するに先立って予め磁性粒子表面
にベーマイト構造を有する水和アルミナ粒子を沈着させ
ておいた場合には、より分散性に優れた磁性粒子粉末が
得られるという事実である。First, the most important point in the present invention is to have a boehmite structure on the magnetic particle surface in advance before coating the particle surface of the magnetic particle with Al or Si or an oxide or hydroxide containing either Al and Si. The fact is that when hydrated alumina particles are deposited, magnetic particle powders with more excellent dispersibility can be obtained.
本発明において分散性に優れた磁性粒子粉末が得られる
理由については未だ明らかではないが、本発明者は、次
のように考えている。The reason why the magnetic particle powder having excellent dispersibility is obtained in the present invention is not yet clear, but the present inventor thinks as follows.
即ち、pH9以上の混合懸濁液中では磁性粒子及び水和ア
ルミナ粒子のいずれもが負電荷に帯電しており、pH4以
下の混合懸濁液中では磁性粒子及び水和アルミナ粒子の
いずれもが正電荷に帯電しており、pH9以上又はpH4以下
のいずれの懸濁液中においても両粒子間に電気的な反発
力が生じ、この反発力が磁性粒子相互の磁性による凝集
力よりも大きい為、磁性粒子相互の凝集が解きほぐされ
る。そして、その後pHを6.5〜8.5に調整することによ
り、pH9以上の懸濁液を用いた場合には磁性粒子が負電
荷に帯電したままであるのに対し、水和アルミナ粒子は
正電荷に帯電し、一方pH4以下の懸濁液を用いた場合に
は水和アルミナ粒子が正電荷に帯電したままであるのに
対し、磁性粒子は負電荷に帯電し、両粒子は相互に反対
の電荷に帯電する為、磁性粒子の粒子表面に水和アルミ
ナ粒子が沈着してその後の再凝集が防止される。その結
果、後のAl又はSi若しくはAl及びSiを含む酸化物或いは
水酸化物を被覆する工程において、磁性粒子の凝集体で
はなく個々の粒子を被覆することが出来ることになる。That is, both magnetic particles and hydrated alumina particles are negatively charged in a mixed suspension of pH 9 or more, and both magnetic particles and hydrated alumina particles are negatively charged in a mixed suspension of pH 4 or less. It is positively charged, and an electric repulsive force is generated between both particles in any suspension of pH 9 or higher or pH 4 or lower, and this repulsive force is larger than the cohesive force due to the magnetism of the magnetic particles. , The mutual aggregation of magnetic particles is loosened. Then, by adjusting the pH to 6.5 to 8.5, the magnetic particles remain negatively charged when a suspension of pH 9 or higher is used, whereas the hydrated alumina particles are positively charged. On the other hand, when using a suspension of pH 4 or less, the hydrated alumina particles remain positively charged, whereas the magnetic particles are negatively charged and both particles have opposite charges. Since the particles are charged, the hydrated alumina particles are deposited on the surface of the magnetic particles and the subsequent re-aggregation is prevented. As a result, in the subsequent step of coating Al or Si or an oxide or hydroxide containing Al and Si, individual particles can be coated instead of the aggregate of magnetic 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 carrying out the present invention will be described.
本発明における磁性粒子粉末としては、マグヘマイト粒
子粉末、マグネタイト粒子粉末、ベルトライド化合物
（FeOx・Fe2O3、０＜ｘ＜１）等の磁性酸化鉄粒子粉末、
これらの磁性酸化鉄粒子粉末にFe以外のCo等の異種金属
を含有させた粒子若しくはこれら磁性酸化鉄粒子にCoを
被着させた粒子、鉄を主成分とする金属磁性粒子及び六
方晶系フェライト粒子等のいずれをも用いることができ
る。Examples of the magnetic particle powder in the present invention include maghemite particle powder, magnetite particle powder, magnetic iron oxide particle powder such as a beltride compound ( FeO x · Fe 2 O 3 , 0 <x <1),
Particles containing different magnetic metals such as Co other than Fe in these magnetic iron oxide particle powders or particles obtained by depositing Co on these magnetic iron oxide particles, metallic magnetic particles containing iron as a main component, and hexagonal ferrite Any of particles and the like can be used.
本発明における水和アルミナは、ベーマイト構造を有す
るものであればいかなる粒子形態を有するものでもよ
く、市販されているものはもちろん、Al塩を含むアルカ
リ水溶液を水熱処理する等により製造したものでもよ
い。The hydrated alumina in the present invention may have any particle morphology as long as it has a boehmite structure, and may be commercially available or may be produced by hydrothermal treatment of an alkaline aqueous solution containing an Al salt. .
水和アルミナの添加量は、磁性粒子粉末に対しAl2O3換
算で0.05〜5.0重量％である。0.05重量％未満の場合に
は、本発明の目的とする効果が得られない。5.0重量％
を越える場合にも本発明の目的とする効果が得られる
が、磁性に関与しない水和アルミナが増加することによ
り飽和磁化が低下する為好ましくない。磁性粒子粉末の
分散性及び飽和磁化を考慮した場合、0.1〜3.0重量％が
好ましい。The amount of hydrated alumina added is 0.05 to 5.0% by weight in terms of Al 2 O 3 based on the magnetic particle powder. If the amount is less than 0.05% by weight, the desired effect of the present invention cannot be obtained. 5.0% by weight
If it exceeds the above range, the effect aimed at by the present invention can be obtained, but it is not preferable because the saturation magnetization is lowered due to the increase of hydrated alumina which is not involved in magnetism. Considering the dispersibility and saturation magnetization of the magnetic particle powder, 0.1 to 3.0% by weight is preferable.
本発明における磁性粒子とベーマイト構造を有する水和
アルミナ粒子との混合懸濁液のpHは９以上又は４以下で
ある。pHが４〜９の間にある時は、磁性粒子と水和アル
ミナ粒子とが反対の電荷に帯電しているか又は反発の電
荷が弱い為電気的な反発が不十分となり、磁性粒子を個
々の粒子に分離することができない。pH9以上又はpH4以
下の混合懸濁液作成時にせん断力を有する機器例えば、
ホモミクサー、ラインミル、サンドグラインドミル等を
用いて機械的処理を行うことによって、一段と優れた分
散効果を得ることが出来る。The pH of the mixed suspension of magnetic particles and hydrated alumina particles having a boehmite structure in the present invention is 9 or more or 4 or less. When the pH is between 4 and 9, the magnetic particles and the hydrated alumina particles are charged with opposite charges or the repulsive charge is weak, resulting in insufficient electric repulsion and Cannot be separated into particles. Equipment having shearing force when creating a mixed suspension of pH 9 or more or pH 4 or less, for example,
By performing mechanical treatment using a homomixer, a line mill, a sand grind mill, etc., a more excellent dispersion effect can be obtained.
本発明における磁性粒子の粒子表面への水和アルミナの
沈着は、pH9以上又はpH4以下の混合懸濁液に酸又はアル
カリ水溶液を添加してpH6.5〜8.5に調整することによっ
て行う。pHの調整により、添加した水和アルミナ粒子は
略全量が沈着する。このpH付近では、水和アルミナは正
電荷を有し、磁性粒子粉末は負電荷を有する為、電気的
な結合が生起し磁性粒子の粒子表面に水和アルミナ粒子
が沈着するのである。pHを調整する為の酸としては、硫
酸、塩酸、酢酸、硝酸等を、アルカリとしては水酸化ナ
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。Deposition of hydrated alumina on the surface of magnetic particles in the present invention is performed by adding an acid or alkali aqueous solution to a mixed suspension having a pH of 9 or more and 4 or less to adjust the pH to 6.5 to 8.5. By adjusting the pH, almost all of the added hydrated alumina particles are deposited. Near this pH, the hydrated alumina has a positive charge and the magnetic particle powder has a negative charge, so that electrical coupling occurs and the hydrated alumina particles are deposited on the surface of the magnetic particles. Sulfuric acid, hydrochloric acid, acetic acid, nitric acid or the like can be used as the acid for adjusting the pH, and sodium hydroxide, potassium hydroxide, aqueous ammonia or the like can be used as the alkali.
本発明において水和アルミナ粒子が沈着している磁性粒
子を含む懸濁液は、アルカリ水溶液を添加してpH10以上
とした後、Alを含む化合物又はSiを含む化合物若しくは
当該両化合物を添加する。pH10以上とするのは、水和ア
ルミナが沈着している磁性粒子を分散状態とし、添加し
た化合物と均一混合させる為である。In the present invention, the suspension containing the magnetic particles in which the hydrated alumina particles are deposited is adjusted to pH 10 or more by adding an alkaline aqueous solution, and then a compound containing Al or a compound containing Si or both the compounds are added. The pH is set to 10 or more so that the magnetic particles in which the hydrated alumina is deposited are in a dispersed state and uniformly mixed with the added compound.
pH10以上にする為のアルカリ水溶液としては水酸化ナト
リウム、水酸化カリウム、アンモニア水等を用いること
ができる。Alを含む化合物としては、アルミン酸ナトリ
ウム、アルミン酸カリウム等のアルミン酸アルカリ、硫
酸アルミニウム、塩化アルミニウム、硝酸アルミニウム
等のアルミニウム塩等を用いることができる。As the alkaline aqueous solution for adjusting the pH to 10 or more, sodium hydroxide, potassium hydroxide, aqueous ammonia, etc. can be used. As the compound containing Al, alkali aluminate such as sodium aluminate and potassium aluminate, aluminum salt such as aluminum sulfate, aluminum chloride and aluminum nitrate can be used.
Alを含む化合物の添加量は、磁性粒子粉末に対し、Al2O
3換算で0.01〜5.0重量％である。0.01重量％未満である
場合には、本発明の効果は得られない。5.0重量％を越
える場合にも本発明の目的とする効果が得られるが磁性
に関与しないAlを含む化合物が増加することにより飽和
磁化が低下する為好ましくない。磁性粒子粉末の分散性
及び飽和磁化を考慮した場合、0.05〜3.0重量％が好ま
しい。The addition amount of the compound containing Al is Al 2 O based on the magnetic particle powder.
It is 0.01 to 5.0% by weight in terms of 3 . If it is less than 0.01% by weight, the effect of the present invention cannot be obtained. Even if the amount exceeds 5.0% by weight, the effect of the present invention can be obtained, but the saturation magnetization is lowered due to the increase of Al-containing compounds not involved in magnetism, which is not preferable. Considering the dispersibility and saturation magnetization of the magnetic particle powder, 0.05 to 3.0% by weight is preferable.
Siを含む化合物としては、ケイ酸ナトリウム、ケイ酸カ
リウム、コロイダルシリカ等を用いることができる。As the compound containing Si, sodium silicate, potassium silicate, colloidal silica or the like can be used.
Siを含む化合物の添加量は、磁性粒子粉末に対し、SiO2
換算で0.01〜5.0重量％である。0.01重量％未満である
場合には、本発明の効果は得られない。5.0重量％を越
える場合にも本発明の目的とする効果が得られるが磁性
に関与しないSiを含む化合物が増加することにより飽和
磁化が低下する為好ましくない。磁性粒子粉末の分散性
及び飽和磁化を考慮した場合、0.1〜2.0重量％が好まし
い。The addition amount of the compound containing Si is SiO 2 with respect to the magnetic particle powder.
It is 0.01 to 5.0% by weight in conversion. If it is less than 0.01% by weight, the effect of the present invention cannot be obtained. Even when the amount exceeds 5.0% by weight, the effect of the present invention can be obtained, but the saturation magnetization is lowered due to the increase of the compound containing Si that is not involved in magnetism, which is not preferable. Considering the dispersibility and saturation magnetization of the magnetic particle powder, 0.1 to 2.0% by weight is preferable.
本発明においてSi化合物及びAl化合物を添加する場合に
は、磁性酸化鉄粒子に対し、Al2O3換算とSiO2換算との
総量で0.01〜5.0重量％、好ましくは0.1〜3.0重量％で
ある。When adding a Si compound and an Al compound in the present invention, the total amount of Al 2 O 3 conversion and SiO 2 conversion is 0.01 to 5.0% by weight, preferably 0.1 to 3.0% by weight, with respect to the magnetic iron oxide particles. .
本発明におけるpH10以上の懸濁液に添加したSi化合物と
Al化合物は、該懸濁液をpH6.5〜8.5に調整することによ
り、Si、Alの酸化物、水酸化物として略全量が磁性粒子
表面に析出、沈着し、被覆膜が生成される。With a Si compound added to a suspension having a pH of 10 or more in the present invention
By adjusting the pH of the suspension to 6.5 to 8.5, the Al compound is deposited on and deposited on the surface of the magnetic particles as Si, Al oxides and hydroxides, and the coating film is formed. .
pHを調整する為の酸としては、硫酸、塩酸、酢酸、硝酸
等を使用することができる。As the acid for adjusting the pH, sulfuric acid, hydrochloric acid, acetic acid, nitric acid or the like can be used.
次に、実施例及び比較例により本発明を説明する。 Next, the present invention will be described with reference to Examples and Comparative Examples.
尚、本発明における分散性の評価は、針状磁性酸化鉄粒
子粉末の場合には、テープ化した場合の残留磁束密度B
r、角型（Br/Bm）及び配向度のそれぞれの値を示すこと
により、板状Baフェライト微粒子粉末の場合には、テー
プ化した場合の飽和磁束密度Bm、角型（Br/Bm）及び光
沢度のそれぞれの値を示すことにより行い、上記のいず
れの値も大きくなる程分散性が改良されたことを意味す
る。Incidentally, the evaluation of the dispersibility in the present invention, in the case of acicular magnetic iron oxide particles powder, the residual magnetic flux density B when taped
In the case of tabular Ba ferrite fine particle powder, the saturation magnetic flux density Bm, the square shape (Br / Bm), and the square shape (Br / Bm) of It shows by showing each value of glossiness, and it means that the dispersibility is improved as any of the above values is increased.
また、板状Baフェライト微粒子を用いてテープ化した場
合の角型の値は、テープ面に対し、垂直方向に磁場配向
させた磁気テープの垂直方向の角型（Br/Bm）を測定
し、反磁場補正を行った値で示した。In addition, the value of the square shape when made into a tape by using plate-like Ba ferrite fine particles is measured by measuring the square shape (Br / Bm) in the vertical direction of the magnetic tape in which the magnetic field is oriented in the direction perpendicular to the tape surface, The values are shown after demagnetizing field correction.
磁性粒子粉末の磁気特性は、「振動試料型磁力計VSM-3S
-15」（東英工業（株）製）を用いて外部磁場10KOeの下
で測定した値であり、磁気テープの諸特性は外部磁場10
KOe（マグヘマイト粒子を用いた場合には5KOe）の下で
測定した結果である。The magnetic properties of the magnetic particle powder are described in "Vibration sample magnetometer VSM-3S
-15 "(manufactured by Toei Industry Co., Ltd.) under an external magnetic field of 10KOe.
It is the result of measurement under KOe (5 KOe when maghemite particles are used).
塗布膜の表面光沢は、日本電色工業（株）製の入射角60
°のグロスメーターで測定した値であり、標準板光沢を
89.0％とした時の値を％表示で示したものである。The surface gloss of the coating film is an incident angle of 60 manufactured by Nippon Denshoku Industries Co., Ltd.
It is the value measured with a gloss meter at
The value when 89.0% is shown in%.
〈磁性粒子粉末の表面処理〉 実施例１〜９、比較例１〜９、参考例１〜3; 実施例１ 長軸0.22μｍ、軸比（長軸：短軸）7.5:1であって保磁
力635OeであるCo被着型針状γ−Fe2O3粒子（Co/全量＝
3.29重量％）を用い、該粒子500gとベーマイト構造を有
する水和アルミナAS-520（日産化学工業（株）製、Al量
はAl2O3換算で20.8重量％に該当する。）24g（Co被着型
γ−Fe2O3に対しAl2O3換算で1.0重量％に該当する。）
とを5lの水に添加、混合した後、水酸化ナトリウムを添
加してpH11.3の混合懸濁液を得た。<Surface Treatment of Magnetic Particle Powder> Examples 1 to 9, Comparative Examples 1 to 9, Reference Examples 1 to 3; Example 1 Long axis 0.22 μm, axial ratio (major axis: minor axis) 7.5: 1 Co-coated acicular γ-Fe 2 O 3 particles with a magnetic force of 635 Oe (Co / total amount =
3.29% by weight) and 500 g of the particles and hydrated alumina AS-520 having a boehmite structure (manufactured by Nissan Chemical Industries, Ltd., the amount of Al corresponds to 20.8% by weight in terms of Al 2 O 3 ) 24 g (Co It corresponds to 1.0% by weight in terms of Al 2 O 3 with respect to the adherend γ-Fe 2 O 3. )
And were added to and mixed with 5 liters of water, sodium hydroxide was added to obtain a mixed suspension having a pH of 11.3.
上記混合懸濁液を攪拌、混合した後、硫酸を添加してpH
7.2に調整し、前記Co被着型γ−Fe2O3粒子表面に水和ア
ルミナ粒子を沈着させた。After stirring and mixing the above mixed suspension, sulfuric acid was added to adjust the pH.
After adjusting to 7.2, hydrated alumina particles were deposited on the surface of the Co-adhered γ-Fe 2 O 3 particles.
反応溶液の一部を抜き取り、常法により過、水洗、乾
燥して得られた茶褐色粒子粉末は、螢光Ｘ線分析の結
果、前記Co被着型γ−Fe2O3粒子表面に存在しているAl
量はAl2O3換算で0.98重量％であった。A part of the reaction solution was taken out, filtered by a conventional method, washed with water, and dried to obtain a brownish brown particle powder. As a result of fluorescent X-ray analysis, the Co-adhered γ-Fe 2 O 3 particles were present on the surface. Al
The amount was 0.98% by weight in terms of Al 2 O 3 .
前記茶褐色沈澱粒子を含む懸濁液に水酸化ナトリウムを
添加してpH10.9とした後、３号水ガラス（徳山曹達
（株）製、Si量は、SiO2換算で29.0重量％に該当す
る。）34.5g（Co被着型γ−Fe2O3に対しSiO2換算で2.0
重量％に該当する。）を添加し、次いで、攪拌、混合し
た後硫酸を添加してpH7.9に調整し、前記茶褐色沈澱粒
子の表面にSiO2被膜を析出させた茶褐色沈澱粒子を得
た。Sodium hydroxide was added to the suspension containing the brown precipitate particles to adjust the pH to 10.9, and then No. 3 water glass (manufactured by Tokuyama Soda Co., Ltd., the Si content corresponds to 29.0 wt% in terms of SiO 2 ). ) 34.5 g (Co-deposited γ-Fe 2 O 3 is 2.0 in terms of SiO 2)
Corresponds to% by weight. ) Was added, followed by stirring and mixing, and then sulfuric acid was added to adjust the pH to 7.9 to obtain brownish brown precipitate particles in which a SiO 2 film was deposited on the surface of the brownish brown precipitate particles.
上記茶褐色沈澱粒子を含む懸濁液を、常法により過、
水洗、乾燥した。The suspension containing the brown-colored precipitated particles is filtered by a conventional method,
It was washed with water and dried.
得られた茶褐色粒子粉末表面に存在しているSiO2量は、
螢光Ｘ線分析の結果、SiO2換算で1.99重量％であった。The amount of SiO 2 present on the surface of the obtained brown particle powder is
As a result of a fluorescent X-ray analysis, it was 1.99% by weight in terms of SiO 2 .
実施例２ 実施例１と同一のCo被着型針状γ−Fe2O3粒子（Co/全量
＝3.29重量％）を用い、該粒子500gとベーマイト構造を
有する水和アルミナAS-520（日産化学工業（株）製、Al
量はAl2O3換算で20.8重量％に該当する。）12.0g（Co被
着型γ−Fe2O3に対しAl2O3換算で0.5重量％に該当す
る。）とを5lの水に添加、混合した後、水酸化ナトリウ
ムを添加してpH10.8の混合懸濁液を得た。Example 2 Using the same Co-coated acicular γ-Fe 2 O 3 particles (Co / total amount = 3.29% by weight) as in Example 1, 500 g of the particles and hydrated alumina AS-520 having a boehmite structure (Nissan Chemical Industry Co., Al
The amount corresponds to 20.8% by weight in terms of Al 2 O 3 . ) 12.0 g (corresponding to 0.5% by weight in terms of Al 2 O 3 with respect to Co-adhered γ-Fe 2 O 3 ) was added to 5 liters of water and mixed, and sodium hydroxide was added to adjust the pH to 10 A mixed suspension of 0.8 was obtained.
上記混合懸濁液を攪拌、混合した後、硫酸を添加してpH
7.1に調整し、前記Co被着型γ−Fe2O3粒子表面に水和ア
ルミナ粒子を沈着させた。After stirring and mixing the above mixed suspension, sulfuric acid was added to adjust the pH.
After adjusting to 7.1, hydrated alumina particles were deposited on the surface of the Co-adhered γ-Fe 2 O 3 particles.
反応溶液の一部を抜き取り、常法により過、水洗、乾
燥して得られた茶褐色粒子粉末は、螢光Ｘ線分析の結
果、前記Co被着型γ−Fe2O3粒子表面に存在しているAl
量はAl2O3換算で0.49重量％であった。A part of the reaction solution was taken out, filtered by a conventional method, washed with water, and dried to obtain a brownish brown particle powder. As a result of fluorescent X-ray analysis, the Co-adhered γ-Fe 2 O 3 particles were present on the surface. Al
The amount was 0.49% by weight in terms of Al 2 O 3 .
前記茶褐色沈澱粒子を含む懸濁液に水酸化ナトリウムを
添加してpH11.8とした後、アルミン酸ナトリウム（米山
薬品工業（株）製、Al量は、Al2O3換算で62重量％に該
当する。）16.1g（Co被着型γ−Fe2O3に対しAl2O3換算
で2.0重量％に該当する。）を添加し、次いで、攪拌、
混合した後硫酸を添加してpH7.0に調整し、前記茶褐色
沈澱粒子の表面に水酸化アルミニウム被膜を析出させた
茶褐色沈澱粒子を得た。Sodium hydroxide was added to the suspension containing the brown precipitate particles to adjust the pH to 11.8, and sodium aluminate (Yoneyama Yakuhin Kogyo Co., Ltd., the amount of Al was 62% by weight in terms of Al 2 O 3 ). 16.1 g (corresponding to 2.0% by weight in terms of Al 2 O 3 with respect to Co-deposited γ-Fe 2 O 3 ), and then stirring,
After mixing, sulfuric acid was added to adjust the pH to 7.0 to obtain brownish brown precipitate particles having an aluminum hydroxide film deposited on the surface of the brownish brown precipitate particles.
上記茶褐色沈澱粒子を含む懸濁液を、常法により過、
水洗、乾燥した。The suspension containing the brown-colored precipitated particles is filtered by a conventional method,
It was washed with water and dried.
得られた茶褐色粒子粉末のAl量は、螢光Ｘ線分析の結
果、Al2O3換算で2.46重量％であり、これから前記のCo
被着型γ−Fe2O3に存在しているAl量を差し引いた1.97
重量％が水酸化ナトリウム被膜中のAl2O3換算でAl量で
ある。The amount of Al in the obtained brown particle powder was 2.46% by weight in terms of Al 2 O 3 as a result of fluorescent X-ray analysis.
1.97 obtained by subtracting the amount of Al existing in the deposited γ-Fe 2 O 3.
Weight% is the amount of Al in terms of Al 2 O 3 in the sodium hydroxide coating.
実施例３〜９ 被処理粒子粉末の種類、混合懸濁液のpH、水和アルミナ
による処理工程における水和アルミナの種類、添加量及
び調整後のpH、Al又はSi若しくはAl及びSiを含む酸化物
層或いは水酸化物層の生成工程における調整後のpH、Al
を含む化合物又はSiを含む化合物の種類、添加量及び調
整後のpHを種々変化させた以外は実施例１と同様にして
茶褐色粒子粉末を得た。Examples 3 to 9 Type of powder to be treated, pH of mixed suspension, type of hydrated alumina in treatment step with hydrated alumina, addition amount and adjusted pH, Al or Si or oxidation containing Al and Si. PH and Al after adjustment in the production process of the oxide layer or hydroxide layer
A brownish brown particle powder was obtained in the same manner as in Example 1 except that the kind of the compound containing Si or the compound containing Si, the addition amount, and the adjusted pH were variously changed.
この時の主要製造条件及び得られた茶褐色粒子粉末の諸
特性を表１に示す。Table 1 shows the main production conditions at this time and various characteristics of the obtained brownish brown particle powder.
比較例１〜９ 水和アルミナによる処理工程を省いた以外は、実施例１
〜９のそれぞれと同様にして茶褐色粒子粉末を得た。Comparative Examples 1 to 9 Example 1 except that the treatment step with hydrated alumina was omitted.
Brown powders were obtained in the same manner as in Nos. 9 to 9.
参考例１〜３ 実施例１、４及び５のそれぞれと同様にして水和アルミ
ナのみによる処理を行い、磁性粒子の粒子表面に水和ア
ルミナが沈着されている磁性粒子粉末を得た。Reference Examples 1 to 3 Treatment with only hydrated alumina was performed in the same manner as in Examples 1, 4 and 5 to obtain magnetic particle powder in which hydrated alumina was deposited on the surface of magnetic particles.
〈磁気テープの製造〉 実施例10〜18、比較例10〜18、参考例４〜6; 実施例10 実施例１で得られた粒子表面と該粒子表面に被覆されて
いる水酸化アルミニウム層との間に水和アルミナ粒子が
存在しているCo被着型針状γ−Fe2O3粒子粉末を用い
て、適量の分散剤、塩ビ酢ビ共重合体、熱可塑製ポリウ
レタン樹脂及びトルエン、メチルエチルケトン、メチル
イソブチルケトンからなる混合溶剤を一定の組成に配合
した後、ボールミルで８時間混合分散して磁気塗料とし
た。<Production of Magnetic Tape> Examples 10 to 18, Comparative Examples 10 to 18, Reference Examples 4 to 6; Example 10 The particle surface obtained in Example 1 and the aluminum hydroxide layer coated on the particle surface. Using Co-coated acicular γ-Fe 2 O 3 particle powder in which hydrated alumina particles are present, an appropriate amount of a dispersant, a vinyl chloride vinyl acetate copolymer, a thermoplastic polyurethane resin and toluene, A mixed solvent composed of methyl ethyl ketone and methyl isobutyl ketone was mixed in a constant composition, and then mixed and dispersed in a ball mill for 8 hours to obtain a magnetic paint.
得られた磁気塗料に上記混合溶剤を加え適正な塗料粘度
になるように調整し、ポリエステル樹脂フィルム上に通
常の方法で塗布、配向、乾燥させて、磁気テープを製造
した。The above-mentioned mixed solvent was added to the obtained magnetic paint to adjust it to an appropriate paint viscosity, which was applied, oriented and dried on a polyester resin film by a usual method to produce a magnetic tape.
この磁気テープの残留磁束密度Brは、1550Gauss、角型
（Br/Bm）は0.84、配向度2.39であった。The residual magnetic flux density Br of this magnetic tape was 1550 Gauss, the square type (Br / Bm) was 0.84, and the orientation degree was 2.39.
実施例11〜13、比較例10〜13、参考例４、５ 実施例２〜４、比較例１〜４及び参考例１〜２のそれぞ
れで得られた針状磁性酸化鉄粒子粉末を用いた以外は、
実施例10と同様にして磁気テープを製造した。Examples 11 to 13, Comparative Examples 10 to 13, Reference Examples 4 and 5 The acicular magnetic iron oxide particle powders obtained in Examples 2 to 4, Comparative Examples 1 to 4 and Reference Examples 1 and 2 were used. except,
A magnetic tape was manufactured in the same manner as in Example 10.
尚、磁性粉末として六方晶系フェライト粒子粉末を用い
た場合には、塗料粘度を調整した磁気塗料をポリエステ
ル樹脂フィルム上に塗布し、該フィルムに対して垂直方
向に配向させた後乾燥させて磁気テープを製造した。When hexagonal ferrite particle powder is used as the magnetic powder, a magnetic paint whose paint viscosity has been adjusted is applied on a polyester resin film, which is then oriented in the direction perpendicular to the film and dried to produce a magnetic powder. A tape was manufactured.
この磁気テープの諸特性を表２に示す。Table 2 shows various characteristics of this magnetic tape.
実施例14〜18、比較例14〜18、参考例６ 実施例５〜９、比較例５〜９、参考例３のそれぞれで得
られた板状Baフェライト微粒子粉末を用いた以外は、実
施例10と同様にして磁気テープを製造した。Examples 14-18, Comparative Examples 14-18, Reference Example 6 Examples except that the plate-like Ba ferrite fine particles obtained in Examples 5-9, Comparative Examples 5-9, and Reference Example 3 were used, respectively. A magnetic tape was manufactured in the same manner as in 10.
この磁気テープの諸特性を表３に示す。Table 3 shows various characteristics of this magnetic tape.
〔発明の効果〕 本発明に係る磁性粒子粉末は、前出実施例に示した通
り、分散性が優れた粒子であるから、高密度記録用磁性
粒子粉末として好適である。 [Effects of the Invention] The magnetic particle powder according to the present invention is suitable for high-density recording because it has excellent dispersibility as shown in the above-mentioned Examples.
Claims (2)
るAl又はSi若しくはAl及びSiのいずれかを含む酸化物層
或いは水酸化物層との間に、ベーマイト構造を有する水
和アルミナ粒子が存在している磁性粒子からなる磁性粒
子粉末。1. A hydrated alumina particle having a boehmite structure between the surface of a magnetic particle and an oxide layer or a hydroxide layer containing Al or Si or Al and Si that coats the surface of the particle. Magnetic particle powder consisting of magnetic particles present in.
ルミナ粒子とを含むpH9以上又は４以下の混合懸濁液に
酸又はアルカリ水溶液を添加してpH6.5〜8.5に調整する
ことにより、前記磁性粒子の粒子表面に前記水和アルミ
ナ粒子を沈着させ、次いで、該水和アルミナ粒子が沈着
している磁性粒子を含む懸濁液にアルカリ水溶液を添加
してpH10以上の懸濁液とした後、該懸濁液にAlを含む化
合物又はSiを含む化合物若しくは当該両化合物を添加
し、次いで酸を添加してpH6.5〜8.5に調整することによ
り、前記水和アルミナ粒子が沈着している磁性粒子の粒
子表面にAl又はSi若しくはAl及びSiのいずれかを含む酸
化物層或いは水酸化物層を生成させることを特徴とする
磁性粒子粉末の製造法。2. A mixed suspension of pH 9 or more or 4 or less containing magnetic particles and hydrated alumina particles having a boehmite structure is adjusted to pH 6.5 to 8.5 by adding an acid or alkali aqueous solution. After depositing the hydrated alumina particles on the surface of the magnetic particles, and then adding an alkaline aqueous solution to the suspension containing the magnetic particles on which the hydrated alumina particles are deposited to form a suspension having a pH of 10 or more. By adding a compound containing Al or a compound containing Si or both compounds to the suspension and then adding an acid to adjust the pH to 6.5 to 8.5, the hydrated alumina particles are deposited. A method for producing magnetic particle powder, which comprises forming an oxide layer or a hydroxide layer containing Al or Si or either Al and Si on the surface of magnetic particles.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62215564A JPH0755828B2 (en) | 1987-08-28 | 1987-08-28 | Magnetic particle powder and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62215564A JPH0755828B2 (en) | 1987-08-28 | 1987-08-28 | Magnetic particle powder and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6461324A JPS6461324A (en) | 1989-03-08 |
| JPH0755828B2 true JPH0755828B2 (en) | 1995-06-14 |
Family
ID=16674517
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62215564A Expired - Fee Related JPH0755828B2 (en) | 1987-08-28 | 1987-08-28 | Magnetic particle powder and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0755828B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0234522A (en) * | 1988-07-22 | 1990-02-05 | Showa Denko Kk | Production of acicular gamma-fe2o3 particles having high transition temperature |
| CN111785470B (en) * | 2020-07-22 | 2023-05-23 | 北京铁路信号有限公司 | Magnetic bead powder and preparation method thereof, laminated magnetic bead and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5583209A (en) * | 1978-12-20 | 1980-06-23 | Hitachi Maxell Ltd | Ferromagnetic powder and preparing the same |
| JPS56130838A (en) * | 1980-03-10 | 1981-10-14 | Ibm | Method of producing magnetic dispersing system |
| JPS5860506A (en) * | 1981-10-07 | 1983-04-11 | Ishihara Sangyo Kaisha Ltd | Magnetic powder with improved dispersibility |
| JPS58127764A (en) * | 1982-01-21 | 1983-07-29 | イ−・アイ・デユ・ポン・ドウ・ヌム−ル・アンド・カンパニ− | Alumina clad tio2 |
| JPS5923505A (en) * | 1982-07-30 | 1984-02-07 | Ishihara Sangyo Kaisha Ltd | Magnetic powder |
-
1987
- 1987-08-28 JP JP62215564A patent/JPH0755828B2/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5583209A (en) * | 1978-12-20 | 1980-06-23 | Hitachi Maxell Ltd | Ferromagnetic powder and preparing the same |
| JPS56130838A (en) * | 1980-03-10 | 1981-10-14 | Ibm | Method of producing magnetic dispersing system |
| JPS5860506A (en) * | 1981-10-07 | 1983-04-11 | Ishihara Sangyo Kaisha Ltd | Magnetic powder with improved dispersibility |
| JPS58127764A (en) * | 1982-01-21 | 1983-07-29 | イ−・アイ・デユ・ポン・ドウ・ヌム−ル・アンド・カンパニ− | Alumina clad tio2 |
| JPS5923505A (en) * | 1982-07-30 | 1984-02-07 | Ishihara Sangyo Kaisha Ltd | Magnetic powder |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6461324A (en) | 1989-03-08 |
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