JP2767048B2 - Needle crystal iron alloy magnetic particles for magnetic recording - Google Patents
Needle crystal iron alloy magnetic particles for magnetic recordingInfo
- Publication number
- JP2767048B2 JP2767048B2 JP1018585A JP1858589A JP2767048B2 JP 2767048 B2 JP2767048 B2 JP 2767048B2 JP 1018585 A JP1018585 A JP 1018585A JP 1858589 A JP1858589 A JP 1858589A JP 2767048 B2 JP2767048 B2 JP 2767048B2
- Authority
- JP
- Japan
- Prior art keywords
- particles
- iron alloy
- alloy magnetic
- acicular
- needle
- 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 52
- 229910000640 Fe alloy Inorganic materials 0.000 title claims description 48
- 230000005291 magnetic effect Effects 0.000 title claims description 15
- 239000013078 crystal Substances 0.000 title claims description 4
- 239000002245 particle Substances 0.000 claims description 68
- 239000000843 powder Substances 0.000 claims description 39
- 229910052796 boron Inorganic materials 0.000 claims description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 9
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 8
- 229910017052 cobalt Inorganic materials 0.000 claims description 8
- 239000010941 cobalt Substances 0.000 claims description 8
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 8
- 230000005415 magnetization Effects 0.000 description 22
- 229910052598 goethite Inorganic materials 0.000 description 17
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 description 17
- 238000007254 oxidation reaction Methods 0.000 description 16
- 238000006722 reduction reaction Methods 0.000 description 14
- 230000003647 oxidation Effects 0.000 description 13
- 238000000034 method Methods 0.000 description 12
- 150000001639 boron compounds Chemical class 0.000 description 10
- 150000001869 cobalt compounds Chemical class 0.000 description 9
- 239000007858 starting material Substances 0.000 description 9
- 239000011248 coating agent Substances 0.000 description 8
- 238000000576 coating method Methods 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- 229910052595 hematite Inorganic materials 0.000 description 6
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 6
- 239000011019 hematite Substances 0.000 description 5
- 239000000725 suspension Substances 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 229910052810 boron oxide Inorganic materials 0.000 description 3
- 229910000428 cobalt oxide Inorganic materials 0.000 description 3
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 description 3
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 239000003513 alkali Substances 0.000 description 2
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000635 electron micrograph Methods 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229910006540 α-FeOOH Inorganic materials 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 241001561902 Chaetodon citrinellus Species 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229940011182 cobalt acetate Drugs 0.000 description 1
- GVPFVAHMJGGAJG-UHFFFAOYSA-L cobalt dichloride Chemical compound [Cl-].[Cl-].[Co+2] GVPFVAHMJGGAJG-UHFFFAOYSA-L 0.000 description 1
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 1
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 1
- 229940044175 cobalt sulfate Drugs 0.000 description 1
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 1
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 1
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005294 ferromagnetic effect Effects 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 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
- 229910052748 manganese Inorganic materials 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 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、高い保磁力と大きな飽和磁化とを有し、且
つ、酸化安定性に優れ、しかも、S.F.D.が優れている針
状晶鉄合金磁性粒子粉末に関するものである。The present invention relates to an acicular iron alloy having a high coercive force and a large saturation magnetization, excellent oxidation stability, and excellent SFD. It relates to magnetic particle powder.
近年、磁気記録再生用機器の小型計量化が進むにつれ
て磁気テープ、磁気ディスク等の磁気記録媒体に対する
高性能化の必要性が益々生じてきている。即ち、高密度
記録、高出力特性、殊に、周波数特性の向上が要求され
る。磁気記録媒体に対する上記のような要求を満足させ
る為に適した磁性粒子粉末の特性は、高い保磁力と大き
な飽和磁化とを有することである。In recent years, as the size of magnetic recording / reproducing devices has been reduced in size, the need for higher performance for magnetic recording media such as magnetic tapes and magnetic disks has been increasing. That is, high-density recording and high output characteristics, particularly, improvement in frequency characteristics are required. Characteristics of the magnetic particle powder suitable for satisfying the above requirements for the magnetic recording medium are to have a high coercive force and a large saturation magnetization.
近年、高出力並びに高密度記録に適する磁性粒子粉
末、即ち、高い保磁力と大きな飽和磁化とを有する磁性
粒子粉末の開発が盛んであり、そのような特性を有する
磁性粒子粉末として針状晶ゲータイト粒子又は針状晶へ
マタイト粒子を還元性ガス中で加熱還元することにより
得られる針状晶鉄合金磁性粒子粉末が知られており実用
化がなされている。In recent years, magnetic particle powders suitable for high-output and high-density recording, that is, magnetic particle powders having high coercive force and large saturation magnetization, have been actively developed, and needle-like goethite is a magnetic particle powder having such characteristics. Acicular iron alloy magnetic particle powders obtained by heating and reducing matite particles into particles or acicular crystals in a reducing gas are known and have been put to practical use.
針状晶鉄合金磁性粒子粉末の保磁力は、粒子の形状、
特に軸比（長軸：短軸）に依存しており、軸比（長軸：
短軸）が大きくなる程保磁力が高くなる傾向にあり、ま
た、飽和磁化は、還元温度を高くして還元を進める程大
きくなる傾向にある。還元の進行にともなって飽和磁化
は向上するが、一方、粒子の形状がくずれて保磁力が低
下するというように両者は逆の相関関係にある為、高い
保磁力と大きな飽和磁化をともに備えた針状晶鉄合金磁
性粒子粉末が強く要求されている。The coercive force of the acicular iron alloy magnetic particles is determined by the shape of the particles,
In particular, it depends on the axial ratio (long axis: short axis), and the axial ratio (long axis:
The coercive force tends to increase as the minor axis increases, and the saturation magnetization tends to increase as the reduction temperature is increased and the reduction proceeds. As the reduction progresses, the saturation magnetization increases, but on the other hand, the two have an inverse correlation, such as the shape of the particles is lost and the coercive force decreases, so both the high coercive force and the large saturation magnetization are provided. Needle-like iron alloy magnetic particles are strongly required.
上述した通り、針状晶鉄合金磁性粒子粉末は、高い保
磁力と大きな飽和磁化とを有するものであるが、磁気記
録媒体用に使用される針状晶鉄合金磁性粒子粉末は１μ
ｍ以下の非常に微細な粒子である為、粒子の表面活性が
非常に大きく、還元後に空気中に取り出すと、空気中の
酸素と急激に反応し、発熱発火するという極めて不安定
なものである。また、同時に上記酸化反応により酸化物
になってしまう為、大幅な磁気特性、殊に、飽和磁化の
減少をきたし、目的とする大きな飽和磁化を有する針状
晶鉄合金磁性粒子粉末を得ることができない為、酸化安
定性に優れていることが強く要求される。As described above, the acicular iron alloy magnetic particle powder has a high coercive force and a large saturation magnetization, but the acicular iron alloy magnetic particle powder used for a magnetic recording medium is 1 μm.
Since the particles are very fine particles of m or less, the surface activity of the particles is very large, and when they are taken out into the air after reduction, they react extremely with oxygen in the air and generate heat and are extremely unstable. . At the same time, since the above-mentioned oxidation reaction results in the formation of an oxide, the magnetic properties, particularly the saturation magnetization, are greatly reduced, and the desired acicular iron alloy magnetic particles having a large saturation magnetization can be obtained. Therefore, it is strongly required to have excellent oxidation stability.
近時、針状晶鉄合金磁性粒子粉末の特性向上に対する
要求は止まることがなく、上記の高い保磁力と大きな飽
和磁化とを有し、且つ、酸化安定性に優れていることに
加えて、更に、S.F.D.（Switching Field Distributio
n）が優れていることが強く要求されている。この事実
は、特開昭63−26821号公報の「第１図は、上記した磁
気ディスクについて測定されたS.F.D.と記録再生出力と
の関係を示す図である。・・・・S.F.D.と記録再生出力
の関係は、第１図から明らかな様に直線になり、これに
より、S.F.D.の小さい強磁性粉末を使うことで、記録再
生出力が上ることがわかる。即ち、記録再生出力を高出
力化するためには、S.F.D.は小さい方が望ましく、通常
以上の出力を得るには、0.6以下のS.F.D.が必要であ
る。」なる記載の通りである。Recently, the demand for improving the properties of acicular iron alloy magnetic particle powder has not stopped, and in addition to having the above high coercive force and large saturation magnetization, and being excellent in oxidation stability, Furthermore, SFD (Switching Field Distributio
n) is strongly required to be excellent. This fact is shown in FIG. 1 of JP-A-63-26821, which shows the relationship between the measured SFD and the read / write output of the magnetic disk described above. The relationship is linear as is clear from Fig. 1. This indicates that the recording / reproducing output can be increased by using a ferromagnetic powder having a small SFD. Therefore, it is desirable that the SFD be small, and to obtain an output higher than usual, an SFD of 0.6 or less is required. "
従来、針状晶鉄合金磁性粒子粉末の特性を改良するこ
とを目的として種々の工夫が試みられており、例えば、
出発原料である針状晶ゲータイト粒子や針状晶へマタイ
ト粒子をあらかじめコバルト化合物で被覆した後加熱還
元する方法（特開昭54−122664号公報、特公昭58−5520
3号公報）、出発原料粒子をあらかじめ硼素化合物で被
覆した後加熱還元する方法（特開昭54−57459号公報、
特公昭54−43832号公報、特開昭58−48611号公報、特開
昭58−46607号公報、特開昭59−5603号公報、特開昭61
−174304号公報、特開昭61−186410号公報、特公昭59−
32881号公報）及び出発原料を水溶性硼素化合物とAl、C
r、Ge、Ndの水溶性塩とで被覆した後加熱還元する方法
（特開昭61−186410号公報）等が知られている。Conventionally, various attempts have been made to improve the properties of acicular iron alloy magnetic particle powder, for example,
Needle-like goethite particles as a starting material or a method of coating needle-like matite particles with a cobalt compound in advance and reducing by heating (Japanese Patent Application Laid-Open No. 54-122664, Japanese Patent Publication No. 58-5520)
No. 3), a method in which starting material particles are coated with a boron compound in advance and then reduced by heating (JP-A-54-57459,
JP-B-54-43832, JP-A-58-48611, JP-A-58-46607, JP-A-59-5603, JP-A-61
JP-174304, JP-A-61-186410, JP-B-59-186
No. 32881) and the starting materials are water-soluble boron compounds and Al, C
A method of coating with a water-soluble salt of r, Ge, and Nd followed by heat reduction (JP-A-61-186410) is known.
高い保磁力と大きな飽和磁化とを有し、且つ、酸化安
定性に優れ、しかも、S.F.D.が優れている針状晶鉄合金
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、上述した通りの公知方法においては、これらの諸特
性を共に兼ね備えた針状晶鉄合金磁性粒子粉末は得られ
ていない。Needle-like iron alloy magnetic particles having a high coercive force and a large saturation magnetization, and having excellent oxidation stability, and also having an excellent SFD, are currently the most required, but as described above. In the known method, acicular iron alloy magnetic particles having all of these properties have not been obtained.
即ち、前出の公知方法による場合には、一般に高い保
磁力と大きな飽和磁化とを有する針状晶鉄合金粒子粉末
が得られているが、例えば、特開昭58−46607号公報に
記載の針状晶鉄合金磁性粒子粉末の酸化安定性は10〜30
％程度、特開昭59−5603号公報に記載の針状晶鉄合金磁
性粒子粉末の酸化安定性は、15％程度であり、酸化安定
性が十分とは言えず、また、後出比較例に示す通り、S.
F.D.も未だ不充分である。That is, in the case of the above-mentioned known method, acicular iron alloy particles having generally high coercive force and large saturation magnetization are obtained, for example, as described in JP-A-58-46607. Oxidation stability of acicular iron alloy magnetic particles is 10-30
%, The oxidative stability of the acicular iron alloy magnetic particles described in JP-A-59-5603 is about 15%, and the oxidative stability is not sufficient. As shown in S.
FD is still inadequate.
そこで、高い保磁力と大きな飽和磁化とを有し、且
つ、酸化安定性に優れ、しかも、S.F.Dが優れている針
状晶鉄合金磁性粒子粉末を得る方法の確立が強く要求さ
れている。Therefore, there is a strong demand for establishing a method for obtaining acicular iron alloy magnetic particles having a high coercive force, a large saturation magnetization, excellent oxidation stability, and excellent SFD.
本発明者は、高い保磁力と大きな飽和磁化とを有し、
且つ、酸化安定性に優れ、しかも、S.F.D.が優れている
針状晶鉄合金磁性粒子粉末を得る方法について種々検討
を重ねた結果、本発明に到達したものである。The inventor has a high coercive force and a large saturation magnetization,
In addition, various studies have been made on a method of obtaining acicular iron alloy magnetic particles having excellent oxidation stability and excellent SFD, and as a result, the present invention has been achieved.
即ち、本発明は、粒子表面近傍に硼素及びコバルトを
含有しており、且つ、S.F.D.が0.50以下である針状晶鉄
合金磁性粒子からなる磁気記録用針状晶鉄合金磁性粒子
粉末である。That is, the present invention is an acicular iron alloy magnetic particle powder for magnetic recording comprising acicular iron alloy magnetic particles containing boron and cobalt near the particle surface and having an SFD of 0.50 or less.
先ず、本発明において最も重要な点は、針状晶ゲータ
イト粒子の粒子表面を硼素化合物とコバルト化合物とで
被覆した後、300〜600℃の温度範囲で加熱処理して硼素
酸化物とコバルト酸化物とで被覆されている針状晶ヘマ
タイト粒子を得、次いで、該針状晶ヘマタイト粒子を35
0〜500℃の温度範囲で加熱還元した場合には、粒子表面
近傍のみにFeに対しＢ換算で1.5〜10モル％の硼素とFe
に対しCo換算で1.5〜10モル％のコバルトとを含有して
いる針状晶鉄合金磁性粒子粉末を得ることができ、該粒
子表面近傍のみにFeに対しＢ換算で1.5〜10モル％の硼
素とFeに対しCo換算で1.5〜10モル％のコバルトとを含
有している針状晶鉄合金磁性粒子粉末は、高い保磁力と
大きな飽和磁化とを有し、且つ、酸化安定性に優れ、し
かも、S.F.D.が優れているという事実である。First, the most important point in the present invention is that, after coating the particle surface of the acicular goethite particles with a boron compound and a cobalt compound, heat treatment is performed at a temperature in the range of 300 to 600 ° C. to form boron oxide and cobalt oxide. To obtain the acicular hematite particles coated with
When heat-reduced in a temperature range of 0 to 500 ° C., 1.5 to 10 mol% of boron and Fe
To obtain a needle-shaped iron alloy magnetic particle powder containing 1.5 to 10 mol% of cobalt in terms of Co, and 1.5 to 10 mol% of B in terms of Fe only in the vicinity of the particle surface. The acicular iron alloy magnetic particle powder containing 1.5 to 10 mol% of cobalt in terms of Co with respect to boron and Fe has high coercive force, large saturation magnetization, and excellent oxidation stability. And it is the fact that SFD is excellent.
本発明における針状晶鉄合金磁性粒子粉末は、1400Oe
以上という高い保磁力を有する。The acicular iron alloy magnetic particle powder in the present invention is 1400 Oe
It has a high coercive force as described above.
本発明における針状晶鉄合金磁性粒子粉末は、130emu
/g以上という大きな飽和磁化を有する。Needle-like iron alloy magnetic particles powder in the present invention, 130 emu
It has a large saturation magnetization of at least / g.
本発明における針状晶鉄合金磁性粒子粉末は、10％以
下という優れた酸化安定性を有するものである。The acicular iron alloy magnetic particles according to the present invention have excellent oxidation stability of 10% or less.
本発明における針状晶鉄合金磁性粒子粉末は、0.50以
下という優れたS.F.D.を有するものである。The acicular iron alloy magnetic particles according to the present invention have an excellent SFD of 0.50 or less.
本発明における高い保磁力と大きな飽和磁化とを有
し、且つ、酸化安定性に優れ、しかも、S.F.D.が優れて
いる針状晶鉄合金磁性粒子粉末は、後出比較例に示す通
り、出発原料粒子を硼素化合物のみで被覆した場合、出
発原料粒子をコバルト化合物のみで被覆した場合、出発
原料粒子中に硼素又はコバルト若しくは当該両元素を含
有させた場合のいずれの場合にも得ることができず、出
発原料粒子を硼素化合物とコバルト化合物とで被覆した
場合にはじめて得られる。The acicular iron alloy magnetic particles having a high coercive force and a large saturation magnetization in the present invention, and having excellent oxidation stability and excellent SFD are, as shown in Comparative Examples below, a starting material. When the particles are coated only with the boron compound, when the starting material particles are coated only with the cobalt compound, it cannot be obtained in any case where boron or cobalt or both elements are contained in the starting material particles. It can be obtained only when the starting material particles are coated with a boron compound and a cobalt compound.
次に、本発明実施にあたっての諸条件について述べ
る。Next, conditions for implementing the present invention will be described.
本発明における針状晶ゲータイト粒子粉末は、周知の
第一鉄塩水溶液と当量以上のアルカリ性溶液とを混合し
て得られる水酸化第一鉄粒子を含む懸濁液をwpH11以上
にて80℃以下の温度で酸素含有ガスを通気して酸化反応
を行う方法及び第一鉄塩水溶液と炭酸アルカリとを反応
させて得られたFeCO3を含む懸濁液に酸素含有ガスを通
気して酸化反応を行なう方法等のいずれの方法によって
も得ることができ、長軸0.1〜0.4μｍ、軸比（長軸：短
軸）5:1〜20:1の粒子を使用することができる。上記ゲ
ータイトの生成反応においては、目的とする針状晶鉄合
金磁性粒子粉末の特性を向上させる為に通常添加される
Ni、Zn、Al、Mn、Cu等の金属イオンを存在させてもよ
い。Needle-like goethite particles powder in the present invention, a suspension containing ferrous hydroxide particles obtained by mixing a well-known aqueous solution of ferrous salt and an equivalent or more of an alkaline solution, wpH 11 or more at 80 ° C. or less A method of performing an oxidation reaction by passing an oxygen-containing gas at a temperature of the temperature, and passing the oxygen-containing gas through a suspension containing FeCO 3 obtained by reacting an aqueous ferrous salt solution with an alkali carbonate to carry out the oxidation reaction For example, particles having a major axis of 0.1 to 0.4 μm and an axial ratio (long axis: short axis) of 5: 1 to 20: 1 can be used. In the formation reaction of the goethite, it is usually added to improve the properties of the target acicular iron alloy magnetic particle powder.
Metal ions such as Ni, Zn, Al, Mn, and Cu may be present.
針状晶鉄合金磁性粒子粉末が好ましいS.F.D.、殊に0.
47以下を有する為には、後者の方法により得られる粒度
が均斉で、且つ、樹枝状粒子が混在していない針状晶ゲ
ータイト粒子を出発原料粒子として使用すればよい。特
に、粒度が均斉で、且つ、樹枝状粒子が混在しない長軸
径0.18〜0.3μｍの粒子であって、軸比（長軸：短軸）
の大きな、殊に、10:1以上の針状晶ゲータイト粒子を出
発原料粒子として使用した場合には、より好ましいS.F.
D.、殊に0.44以下を有する針状晶鉄合金磁性粒子粉末を
得ることができる。Needle-like iron alloy magnetic particle powders are preferred SFD, especially 0.
To have a particle size of 47 or less, acicular goethite particles having a uniform particle size obtained by the latter method and containing no dendritic particles may be used as starting material particles. In particular, particles having a long axis diameter of 0.18 to 0.3 μm in which the particle size is uniform and the dendritic particles are not mixed, and the axial ratio (long axis: short axis)
In particular, when needle-like goethite particles of 10: 1 or more are used as starting material particles, a more preferable SF
D. In particular, acicular iron alloy magnetic particles having a particle size of 0.44 or less can be obtained.
本発明における硼素化合物としては、KBO2、H3BO3、H
BO2、B2O3等を使用することができる。針状晶ゲータイ
ト粒子の硼素化合物による被覆は、硼素を含む水溶液と
針状晶ゲータイト粒子とを混合撹拌した後、濾別、乾燥
することによって行うことができる。硼素化合物による
被覆量は、Feに対しＢ換算で1.5〜10モル％である。1.5
モル％未満の場合には、粒子及び粒子相互間の焼結が生
起し、高い保磁力を有する針状晶鉄合金磁性粒子粉末を
得ることができない。10モル％を越える場合には、還元
反応の進行が妨げられる為針状晶鉄合金磁性粒子粉末を
得ることが困難となる。As the boron compound in the present invention, KBO 2 , H 3 BO 3 , H
BO 2 , B 2 O 3 and the like can be used. The coating of the needle-like goethite particles with the boron compound can be performed by mixing and stirring the aqueous solution containing boron and the needle-like goethite particles, followed by filtration and drying. The coating amount of the boron compound is 1.5 to 10 mol% in terms of B with respect to Fe. 1.5
When the amount is less than mol%, sintering between the particles and the particles occurs, and it is not possible to obtain the acicular iron alloy magnetic particle powder having a high coercive force. If it exceeds 10 mol%, it is difficult to obtain acicular iron alloy magnetic particles because the progress of the reduction reaction is hindered.
本発明におけるコバルト化合物としては、硫酸コバル
ト、硝酸コバルト、酢酸コバルト、塩化コバルト等を使
用することができる。針状晶ゲータイト粒子のコバルト
化合物による被覆は、コバルトを含む水溶液と針状晶ゲ
ータイト粒子とを混合撹拌した後、又は、必要により、
アルカリ水溶液で中和した後、濾別、乾燥することによ
って行うことができる。コバルト化合物による被覆量
は、Feに対しCo換算で1.5〜10モル％である。1.5モル％
未満の場合には、飽和磁化が130emu/g以下、S.F.D.が0.
50以上となり、本発明の目的とする針状晶鉄合金磁性粒
子粉末を得ることができない。10モル％を越える場合に
も本発明の目的とする針状晶鉄合金磁性粒子粉末を得る
ことが出来るが、必要以上に含有させる意味がない。As the cobalt compound in the present invention, cobalt sulfate, cobalt nitrate, cobalt acetate, cobalt chloride and the like can be used. The coating of the acicular goethite particles with the cobalt compound is performed after mixing and stirring the aqueous solution containing cobalt and the acicular goethite particles, or, if necessary,
After neutralization with an aqueous alkali solution, it can be carried out by filtration and drying. The coating amount of the cobalt compound is 1.5 to 10 mol% in terms of Co with respect to Fe. 1.5 mol%
If less, the saturation magnetization is 130 emu / g or less and the SFD is 0.
If it is 50 or more, it is not possible to obtain the acicular iron alloy magnetic particle powder intended for the present invention. If it exceeds 10 mol%, the acicular iron alloy magnetic particle powder intended for the present invention can be obtained, but there is no point in containing more than necessary.
本発明における針状晶ゲータイト粒子の粒子表面を硼
素化合物とコバルト化合物とで被覆する順序は、いずれ
が先でも、また、同時であってもよい。In the present invention, the order of coating the particle surface of the acicular goethite particles with the boron compound and the cobalt compound may be either first or simultaneous.
本発明における加熱焼成温度は、300〜600℃である。
300℃未満である場合には、粒子の高密度化が困難であ
る為、後の還元工程における加熱時に粒子の形状を保持
することができず、針状晶鉄合金磁性粒子粉末の保磁力
が低下してしまい、また、S.F.D.を0.5以下とすること
が出来ない。S.F.D.が改良されない理由について、加熱
焼成温度が300℃未満である場合には、再結晶化が不十
分になる為、還元後の粒子の形状分布による形状異方性
の不均一化やFe、Ｂ、Coの構造的な分布による結晶異方
性の不均一化を招来するものと考えられる。600℃を越
える場合には、粒子及び粒子相互間で焼結が生起し、粒
子の形状が崩れる。The heating and firing temperature in the present invention is 300 to 600 ° C.
If the temperature is lower than 300 ° C., since it is difficult to increase the density of the particles, it is not possible to maintain the shape of the particles during heating in the subsequent reduction step, and the coercive force of the acicular iron alloy magnetic particles is reduced. The SFD cannot be reduced to 0.5 or less. Regarding the reason why the SFD is not improved, if the heating and firing temperature is lower than 300 ° C, recrystallization is insufficient, so that the shape distribution of reduced particles causes non-uniform shape anisotropy and Fe, B It is considered that this leads to non-uniformity of crystal anisotropy due to the structural distribution of Co. When the temperature exceeds 600 ° C., sintering occurs between the particles and the particles, and the shape of the particles is lost.
本発明における加熱還元温度は、300〜500℃である。
300℃未満である場合には、還元反応が不充分であり、
大きな飽和磁化を有する針状晶鉄合金磁性粒子粉末を得
ることができない。500℃を越える場合には、粒子及び
粒子相互間で焼結が生起し、粒子の形状がくずれる為、
針状晶鉄合金磁性粒子粉末の保磁力が低下する。The heat reduction temperature in the present invention is 300 to 500 ° C.
If the temperature is lower than 300 ° C., the reduction reaction is insufficient,
Needle-like iron alloy magnetic particles having large saturation magnetization cannot be obtained. If the temperature exceeds 500 ° C, sintering occurs between the particles and the particles, and the shape of the particles is distorted.
The coercive force of the acicular iron alloy magnetic particles decreases.
本発明において得られる針状晶鉄合金磁性粒子粉末
は、長軸0.1〜0.4μｍ、軸比（長軸：短軸）5:1〜15:1
の範囲である。The acicular iron alloy magnetic particles obtained in the present invention have a major axis of 0.1 to 0.4 μm and an axial ratio (long axis: short axis) of 5: 1 to 15: 1.
Range.
本発明における加熱還元後の針状晶鉄合金磁性粒子粉
末は、周知の方法、例えば、トルエン等の有機溶剤中に
浸漬する方法及び還元後の雰囲気を不活性ガスに置換し
た後、不活性ガス中の酸素含有量を徐々に増加させなが
ら最終的に空気によって徐酸化する方法等により空気中
に取り出すことができる。The needle-like iron alloy magnetic particles powder after heat reduction in the present invention is a known method, for example, a method of immersing in an organic solvent such as toluene, and after replacing the atmosphere after reduction with an inert gas, an inert gas. It can be taken out into the air by a method such as gradually oxidizing it with air while gradually increasing the oxygen content therein.
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 described with reference to Examples and Comparative Examples.
尚、以下の実施例並びに比較例における粒子の長軸、
軸比（長軸：短軸）は、電子顕微鏡写真から測定した数
値の平均値で示した。針状晶鉄合金磁性粒子粉末の磁気
特性は、「振動試料型磁力計VSM−3S−15N（東英工業
（株）製）を使用し、外部磁場10KOeまでかけて測定し
た。酸化安定性は、温度60℃、相対湿度90％の雰囲気
で、７日間放置した後の飽和磁化減少率（％）で示し
た。S.F.D.の測定は、下記の方法により得られた角型0.
85を有するシート状試料片を用い、前記磁気測定器の微
分回路を使用して、保磁力の微分曲線を得、この曲線の
半値巾を測定し、この値を曲線のピーク値の保磁力で除
することにより求めた。Incidentally, the major axis of the particles in the following Examples and Comparative Examples,
The axial ratio (long axis: short axis) was indicated by the average value of numerical values measured from an electron micrograph. The magnetic properties of the acicular iron alloy magnetic particles were measured using a vibrating sample magnetometer VSM-3S-15N (manufactured by Toei Kogyo Co., Ltd.) up to an external magnetic field of 10 KOe. The saturation magnetization reduction rate (%) after standing for 7 days in an atmosphere at a temperature of 60 ° C. and a relative humidity of 90% was measured.
Using a sheet-shaped sample piece having 85, a derivative circuit of the coercive force was obtained by using the differentiating circuit of the magnetometer, the half width of this curve was measured, and this value was calculated as the coercive force of the peak value of the curve. It was determined by dividing.
シート状試料片は、下記の成分を100ccのポリビンに
下記の割合で入れた後、レッドデビルで８時間混合分散
を行うことにより調整した磁性塗料を厚さ25μｍのポリ
エチレンテレフタレートフィルム上にアプリケーターを
用いて50μｍの厚さに塗布し、次いで、３〜5KGaussの
磁場中で乾燥させることにより得た。A sheet-like sample piece was prepared by adding the following components to a 100 cc polyvin at the following ratio, and then mixing and dispersing the mixture in a red devil for 8 hours. To a thickness of 50 μm and then dried in a magnetic field of 3-5 Kgauss.
3mmφステンレスボール 800重量部 鉄合金磁性粒子粉末 100重量部 スルホン酸ナトリウム基を有するポリウレタン樹脂 20重量部 シクロヘキサノン 83.3重量部 メチルエチルケトン 83.3重量部 トルエン 83.3重量部 ＜針状晶ヘマタイト粒子粉末の製造＞ 実施例１〜10 比較例１〜9; 実施例１ 長軸0.21μｍ、軸比（長軸：短軸）12:1の針状晶ゲー
タイト粒子100gを１の水中に懸濁させた。3 mmφ stainless steel ball 800 parts by weight Iron alloy magnetic particle powder 100 parts by weight Polyurethane resin having sodium sulfonate group 20 parts by weight Cyclohexanone 83.3 parts by weight Methyl ethyl ketone 83.3 parts by weight Toluene 83.3 parts by weight <Production of needle-like hematite particle powder> Comparative Examples 1 to 9; Example 1 100 g of acicular goethite particles having a major axis of 0.21 μm and an axial ratio (major axis: minor axis) of 12: 1 were suspended in 1 water.
上記懸濁液にH3BO310.0g（針状晶ゲータイト粒子に対
して10.0wt％に該当する。）及びCo（CH3COO）２・4H2O
13.0g（針状晶ゲータイト粒子に対して13.0gw％に該当
する。）を添加して10分間撹拌した。この時の懸濁液の
pHは6.2であった。次いで、NH4OHを添加して懸濁液のpH
を9.3とした後、針状晶α−FeOOH粒子を濾別、乾燥して
硼素とコバルトとで被覆されている針状晶α−FeOOH粒
子を得た。(Corresponding to 10.0 wt% relative to the needles goethite particles.) H 3 BO 3 10.0g of the above suspension and Co (CH 3 COO) 2 · 4H 2 O
13.0 g (corresponding to 13.0 gw% based on the needle goethite particles) was added, and the mixture was stirred for 10 minutes. Of the suspension at this time
pH was 6.2. Then, NH 4 OH was added to adjust the pH of the suspension.
Was adjusted to 9.3, and the needle-like α-FeOOH particles were separated by filtration and dried to obtain needle-like α-FeOOH particles coated with boron and cobalt.
上記硼素とコバルトとで被覆されている針状晶ゲータ
イト粒子50gを空気中400℃で加熱処理して、硼素酸化物
とコバルト酸化物とで被覆されている針状晶ヘマタイト
粒子粉末を得た。この粒子粉末は、電子顕微鏡写真観察
の結果、平均値で長軸0.19μｍ、軸比（長軸：短軸）1
1:1であった。50 g of the acicular goethite particles coated with boron and cobalt were heat-treated at 400 ° C. in air to obtain acicular hematite particles powder coated with boron oxide and cobalt oxide. As a result of electron micrograph observation, the average particle diameter of the particle powder was 0.19 μm, and the axial ratio (long axis: short axis) was 1
It was 1: 1.
実施例２〜10、比較例１〜９ 針状晶ゲータイト粒子粉末の種類、硼素化合物の種
類、量及び存在時期、コバルト化合物の種類、量及び存
在時期並びに加熱焼成工程における温度を種々変化させ
た以外は、実施例１と同様にして針状晶ヘマタイト粒子
粉末を得た。Examples 2 to 10, Comparative Examples 1 to 9 The type of needle-like goethite particle powder, the type, amount and existence time of the boron compound, the type, amount and existence time of the cobalt compound and the temperature in the heating and firing step were variously changed. Except for the above, a needle-like hematite particle powder was obtained in the same manner as in Example 1.
この時の主要製造条件及び諸特性を表１に示す。 Table 1 shows the main manufacturing conditions and various characteristics at this time.
＜針状晶鉄合金磁性粒子粉末の製造＞ 実施例11〜20 比較例10〜20; 実施例11 実施例１で得られた硼素酸化物とコバルト酸化物とで
被覆されている針状晶ヘマタイト粒子粉末20gを水素気
流中410℃で６時間還元して針状晶鉄合金磁性粒子粉末
を得た。<Production of Acicular Iron Alloy Magnetic Particle Powder> Examples 11 to 20 Comparative Examples 10 to 20; Example 11 Acicular Hematite Coated with Boron Oxide and Cobalt Oxide Obtained in Example 1 20 g of the particle powder was reduced in a hydrogen stream at 410 ° C. for 6 hours to obtain acicular iron alloy magnetic particle powder.
還元して得られた針状晶鉄合金磁性粒子粉末は、空気
中に取り出したとき急激な酸化を起こさないように、粒
子表面に安定な酸化被膜を施した。得られた針状晶鉄合
金磁性粒子粉末は、螢光Ｘ線分析の結果、ＢをFeに対し
4.7モル％、CoをFeに対し4.5モル％含有するものであ
り、また、電子顕微鏡観察の結果、長軸0.15μｍ、軸比
（長軸：短軸）7:1であった。磁気特性は、保磁力Hcが1
530Oe、飽和磁化σｓが133emu/gであり、酸化安定性
は、8.0％、S.F.D.は0.43であった。The needle-like iron alloy magnetic particle powder obtained by the reduction was coated with a stable oxide film on the particle surface so as not to cause rapid oxidation when taken out into the air. The obtained acicular iron alloy magnetic particle powder was analyzed by fluorescent X-ray analysis,
It contained 4.7 mol% and 4.5 mol% of Co with respect to Fe. As a result of observation with an electron microscope, the major axis was 0.15 μm and the axial ratio (major axis: minor axis) was 7: 1. The magnetic properties show that the coercive force Hc is 1
530 Oe, saturation magnetization s was 133 emu / g, oxidation stability was 8.0%, and SFD was 0.43.
実施例12〜20、比較例10〜20 針状晶ヘマタイト粒子粉末の種類並びに加熱還元工程
における温度及び時間を種々変化させた以外は、実施例
11と同様にして針状晶鉄合金磁性粒子粉末を得た。Examples 12 to 20, Comparative Examples 10 to 20 Example except that the type of the acicular haematite particles and the temperature and time in the heat reduction step were variously changed.
In the same manner as in No. 11, acicular iron alloy magnetic particle powder was obtained.
この時の主要製造条件及び諸特性を表２に示す。 Table 2 shows the main manufacturing conditions and various characteristics at this time.
〔発明の効果〕 本発明に係る針状晶鉄合金磁性粒子粉末は、前出実施
例に示した通り、高い保磁力と大きな飽和磁化とを有
し、且つ、酸化安定性に優れ、しかも、S.F.D.が優れて
いる粒子粉末であるので、現在、最も要求されている高
密度記録用、高出力用磁性粒子粉末として好適である。 [Effect of the Invention] The acicular iron alloy magnetic particle powder according to the present invention has a high coercive force and a large saturation magnetization, as shown in the above Examples, and has excellent oxidation stability, and Since SFD is an excellent particle powder, it is suitable as a magnetic particle powder for high-density recording and high output, which is the most required at present.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｃ０９Ｄ 7/12 Ｃ２２Ｃ 38/10 Ｃ２２Ｃ 38/10 Ｇ１１Ｂ 5/842 Ａ Ｇ１１Ｂ 5/842 Ｈ０１Ｆ 1/06 Ｋ (72)発明者 沖中 健二 広島県広島市中区舟入南４丁目１番２号 戸田工業株式会社創造センター内 (72)発明者 池本 邦生 広島県広島市中区舟入南４丁目１番２号 戸田工業株式会社創造センター内 (72)発明者 森 幸治 広島県広島市中区舟入南４丁目１番２号 戸田工業株式会社創造センター内 (72)発明者 永井 規道 広島県広島市中区舟入南４丁目１番２号 戸田工業株式会社創造センター内 審査官 北村 明弘 (56)参考文献 特開 昭51−67250（ＪＰ，Ａ) 特開 昭55−161007（ＪＰ，Ａ) 特開 昭63−102304（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) B22F 1/00 - 1/02 B22F 9/22 G11B 5/706,5/842 H01F 1/06──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 6 Identification code FI C09D 7/12 C22C 38/10 C22C 38/10 G11B 5/842 A G11B 5/842 H01F 1/06 K (72) Inventor Oki Kenji Naka 41-2, Funairi Minami, Naka-ku, Hiroshima City, Hiroshima Pref. Toda Kogyo Co., Ltd. (72) Inventor Kunio Ikemoto 4-1-2, Funairi Minami, Naka-ku, Hiroshima City, Hiroshima Toda Kogyo Co., Ltd. (72) Inventor Koji Mori 4-1-2, Funariminami, Naka-ku, Hiroshima-shi, Hiroshima Toda Kogyo Co., Ltd. (72) Inventor Norimichi Nagai 4-1-2, Funariminami, Naka-ku, Hiroshima-shi, Hiroshima No. Toda Kogyo Co., Ltd. Creative Center Examiner Akihiro Kitamura (56) References JP-A-51-67250 (JP, A) JP-A-55-161007 (JP, A) JP-A-63-102304 (J (P, A) (58) Fields investigated (Int. Cl. 6 , DB name) B22F 1/00-1/02 B22F 9/22 G11B 5 / 706,5 / 842 H01F 1/06
Claims (1)
〜10モル％の硼素とFeに対しCo換算で1.5〜10モル％の
コバルトとを含有しており、且つ、S.F.D.が0.50以下で
ある針状晶鉄合金磁性粒子からなる磁気記録用針状晶鉄
合金磁性粒子粉末。(1) Only in the vicinity of the particle surface, Fe is converted to B by 1.5%.
Needle-like crystals for magnetic recording, comprising needle-like iron alloy magnetic particles containing up to 10 mol% of boron and 1.5 to 10 mol% of cobalt in terms of Co with respect to Fe and having an SFD of 0.50 or less. Iron alloy magnetic particle powder.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1018585A JP2767048B2 (en) | 1989-01-27 | 1989-01-27 | Needle crystal iron alloy magnetic particles for magnetic recording |
| EP89308004A EP0379776B1 (en) | 1989-01-27 | 1989-08-07 | Acicular magnetic iron based alloy particles for magnetic recording and method of producing the same |
| DE68918836T DE68918836T2 (en) | 1989-01-27 | 1989-08-07 | Needle-shaped magnetic particles made of an iron alloy for magnetic recording and process for their production. |
| US07/728,328 US5156922A (en) | 1989-01-27 | 1991-07-08 | Acicular magnetic iron based alloy particles for magnetic recording and method of producing the same |
| US07/921,093 US5238483A (en) | 1989-01-27 | 1992-07-29 | Acicular magnetic iron based alloy particles for magnetic recording and method of producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1018585A JP2767048B2 (en) | 1989-01-27 | 1989-01-27 | Needle crystal iron alloy magnetic particles for magnetic recording |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02197503A JPH02197503A (en) | 1990-08-06 |
| JP2767048B2 true JP2767048B2 (en) | 1998-06-18 |
Family
ID=11975705
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1018585A Expired - Fee Related JP2767048B2 (en) | 1989-01-27 | 1989-01-27 | Needle crystal iron alloy magnetic particles for magnetic recording |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2767048B2 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5167250A (en) * | 1974-12-09 | 1976-06-10 | Fuji Photo Film Co Ltd | |
| JPS5853686B2 (en) * | 1979-05-31 | 1983-11-30 | 戸田工業株式会社 | Method for producing acicular crystal metal iron magnetic particle powder |
| JPS63102304A (en) * | 1986-10-20 | 1988-05-07 | Nippon Steel Corp | Fe-ni alloy magnetic particle powder and manufacture thereof |
-
1989
- 1989-01-27 JP JP1018585A patent/JP2767048B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02197503A (en) | 1990-08-06 |
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| Date | Code | Title | Description |
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| LAPS | Cancellation because of no payment of annual fees |