JPH02197503A - Magnetic acicular iron alloy powder for magnetic recording and its production - Google Patents
Magnetic acicular iron alloy powder for magnetic recording and its productionInfo
- Publication number
- JPH02197503A JPH02197503A JP1018585A JP1858589A JPH02197503A JP H02197503 A JPH02197503 A JP H02197503A JP 1018585 A JP1018585 A JP 1018585A JP 1858589 A JP1858589 A JP 1858589A JP H02197503 A JPH02197503 A JP H02197503A
- Authority
- JP
- Japan
- Prior art keywords
- particles
- iron alloy
- acicular
- acicular iron
- alloy magnetic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910000640 Fe alloy Inorganic materials 0.000 title claims abstract description 53
- 230000005291 magnetic effect Effects 0.000 title claims abstract description 24
- 239000000843 powder Substances 0.000 title claims abstract description 16
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- 239000002245 particle Substances 0.000 claims abstract description 82
- 229910052598 goethite Inorganic materials 0.000 claims abstract description 22
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 claims abstract description 22
- 229910052595 hematite Inorganic materials 0.000 claims abstract description 13
- 239000011019 hematite Substances 0.000 claims abstract description 13
- 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 13
- 229910052796 boron Inorganic materials 0.000 claims abstract description 12
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052810 boron oxide Inorganic materials 0.000 claims abstract description 6
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000006249 magnetic particle Substances 0.000 claims description 55
- 150000001639 boron compounds Chemical class 0.000 claims description 12
- 150000001869 cobalt compounds Chemical class 0.000 claims description 12
- 229910017052 cobalt Inorganic materials 0.000 claims description 9
- 239000010941 cobalt Substances 0.000 claims description 9
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 9
- 229910000428 cobalt oxide Inorganic materials 0.000 claims description 5
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 claims description 5
- 230000005415 magnetization Effects 0.000 abstract description 23
- 238000007254 oxidation reaction Methods 0.000 abstract description 19
- 230000003647 oxidation Effects 0.000 abstract description 17
- 238000010438 heat treatment Methods 0.000 abstract description 11
- 239000011248 coating agent Substances 0.000 abstract description 6
- 238000000576 coating method Methods 0.000 abstract description 6
- 239000006247 magnetic powder Substances 0.000 abstract 1
- 229910052717 sulfur Inorganic materials 0.000 description 21
- 238000006722 reduction reaction Methods 0.000 description 14
- 238000000034 method Methods 0.000 description 11
- 239000007858 starting material Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 239000000725 suspension Substances 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
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 2
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 2
- 238000000635 electron micrograph Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- -1 polyethylene Polymers 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229910006540 α-FeOOH Inorganic materials 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 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
- 101100070542 Podospora anserina het-s gene Proteins 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 238000006243 chemical reaction Methods 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
- 238000010586 diagram Methods 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
- 230000020169 heat generation Effects 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 229910052742 iron Inorganic materials 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
- 239000000463 material Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000011946 reduction process Methods 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
- 239000010959 steel Substances 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
Landscapes
- Manufacturing Of Magnetic Record Carriers (AREA)
- Hard Magnetic Materials (AREA)
- Paints Or Removers (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Powder Metallurgy (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、ＳＪ、Ｄ、が優れている
針状晶鉄合金磁性粒子粉末及びその製造法に間するもの
である。[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides an acicular material having high coercive force and large saturation magnetization, excellent oxidation stability, and excellent SJ and D. The present invention relates to crystalline iron alloy magnetic particles and a method for producing the same.
近年、磁気記録再生用機器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 magnetic recording and reproducing equipment has become smaller and lighter, there has been an increasing need for higher performance magnetic recording media such as magnetic tapes and magnetic disks. That is, high-density recording, high output characteristics, and especially improved frequency characteristics are required. The characteristics of magnetic particles suitable for satisfying the above requirements for magnetic recording media are that they have high coercive force and 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ヘマタ
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 particles suitable for high output and high density recording,
That is, the development of magnetic particles having high coercive force and large saturation magnetization is active, and as magnetic particles having such characteristics, acicular goethite particles or acicular hematite particles are heated in a reducing gas. Acicular iron alloy magnetic particles obtained by reduction are known and have been put into 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。The coercive force of acicular iron alloy magnetic particles depends on the particle shape, especially the axial ratio (long axis: short axis), and the larger the axial ratio (long axis: short axis), the higher the coercive force. Moreover, the saturation magnetization tends to increase as the reduction temperature increases and the reduction progresses.
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。As the reduction progresses, the saturation magnetization improves, but on the other hand,
Since the shape of the particles is distorted and the coercive force decreases, there is an inverse correlation between the two, so there is a strong demand for acicular iron alloy magnetic particles that have both a high coercive force and a large saturation magnetization.
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１１Ｉ
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 mentioned above, the acicular iron alloy magnetic particles have a high coercive force and large saturation magnetization, but the acicular iron alloy magnetic particles used for magnetic recording media have 11I
Because they are very fine particles of less than m in size, they have a very high surface activity, and when taken out into the air after reduction, they rapidly react with oxygen in the air, causing heat generation and ignition, making them extremely unstable. . At the same time, since the oxidation reaction turns into an oxide, the magnetic properties, especially the saturation magnetization, are significantly reduced, making it difficult to obtain the desired acicular iron alloy magnetic particles having a large saturation magnetization. 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 Ｆ
ｉｅｌｄ Ｄｉｓｔｒｉｂｕｔｉｏｎ）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６３−２
６８２１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、ｐ、ｏ、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。In recent years, there has been an unstoppable demand for improved properties of acicular iron alloy magnetic particles, and in addition to having the above-mentioned high coercive force and large saturation magnetization, and excellent oxidation stability, Furthermore, S, F, D, (Switching F
There is a strong demand for excellent yield distribution. This fact is
No. 6821, ``Figure 1 is a diagram showing the relationship between S, F, D, and recording/reproducing output measured for the above magnetic disk....S, F, D, and recording/reproducing output. As is clear from Figure 1, the output relationship is a straight line, which means that by using ferromagnetic powder with small s, p, and o,
It can be seen that the recording and playback output increases. That is, in order to increase the recording/reproduction output, it is desirable that S, F, and D be smaller.
F, D, are required. ” as stated.
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ヘマタイト
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５
８−５５２０３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５４−４２８３２号公報、特
開昭５８−４８６１１号公報、特開昭５８−４６６０７
号公報、特開昭５９−３２８８１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５９−３２８８
１号公報）及び出発原料を水溶性硼素化合物とＡｌ５Ｃ
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。In the past, various attempts have been made to improve the properties of acicular iron alloy magnetic particles. For example, the starting materials, acicular goethite particles and acicular hematite particles, have been treated with a cobalt compound in advance. Method of heating and reducing after coating (JP-A-54-122664, JP-A-5
No. 8-55203), a method in which starting material particles are coated with a boron compound in advance and then thermally reduced (Japanese Patent Application Laid-open No. 1986-
57459, JP 54-42832, JP 58-48611, JP 58-46607
No. 1, JP-A-59-32881, JP-A-59-
5603, JP 61-174304, JP 61-186410, JP 59-3288
No. 1) and the starting materials are a water-soluble boron compound and Al5C.
A method of coating with a water-soluble salt of r, Ge, or Nd and then reducing by heating (Japanese Unexamined Patent Publication No. 186410/1983) 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、（１，が優れている針状晶
鉄合金磁性粒子粉末は、現在量も要求されているところ
であるが、上述した通りの公知方法においては、これら
の緒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。Acicular iron alloy magnetic particles having high coercive force and large saturation magnetization, excellent oxidation stability, and excellent S, F, (1) are currently in demand in quantity. However, in the known methods as described above, 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１
０〜３０％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。That is, in the case of the above-mentioned known method, acicular iron alloy particles having a high coercive force and a large saturation magnetization are generally obtained. The oxidation stability of acicular iron alloy magnetic particles is 1
The oxidation stability of the acicular iron alloy magnetic particles described in JP-A-59-5603 is about 15%, which cannot be said to be sufficient. As shown in the comparative example, S, F, D.
も未だ不充分である。is still insufficient.
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, it has high coercive force and large saturation magnetization, and
There is a strong demand for establishing a method for obtaining acicular iron alloy magnetic particles having excellent oxidation stability and excellent S, F, and D values.
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。The present inventor has found that S, F, and D have high coercive force, large saturation magnetization, and excellent oxidation stability.
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 present invention was achieved as a result of various studies on methods for obtaining acicular iron alloy magnetic particles with excellent properties.
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
磁性粒子粉末及び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、３００〜６
００℃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３５０〜５００℃の
温度範囲で加熱還元することからなる粒子表面近傍に硼
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の製造法である。That is, the present invention provides acicular iron alloy magnetic particles for magnetic recording that contain boron and cobalt near the particle surface and have S, F, and D of 0.50 or less. After coating the particle surfaces of the alloy magnetic particles and the acicular goethite particles with a boron compound and a cobalt compound,
obtaining acicular hematite particles coated with boron oxide and cobalt oxide by heat treatment in a temperature range of 00°C;
Next, the acicular hematite particles are heated and reduced in a temperature range of 350 to 500°C, and contain boron and cobalt near the particle surface, and have S, F, and D of 0.50 or less. This is a method for producing acicular iron alloy magnetic particles for magnetic recording, which are made of certain acicular iron alloy magnetic particles.
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、咳針状晶ヘマタイト粒子
を３５０〜５００℃の温度範囲で加熱還元した場合には
、粒子表面近傍に硼素及びコバルト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
傍に硼素及びコバルト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。First, the most important point in the present invention is that the surface of the acicular goethite particles is coated with a boron compound and a cobalt compound, and then heat-treated in a temperature range of 300 to 600°C to form boron oxide and cobalt oxide. When the needle-like hematite particles are obtained and then heated and reduced in a temperature range of 350 to 500°C, boron and cobalt are contained near the particle surface. Acicular iron alloy magnetic particles can be obtained, and the acicular iron alloy magnetic particles containing boron and cobalt near the particle surface have high coercive force and large saturation magnetization, and , excellent oxidation stability, and S, F.
Ｄ、が優れているという事実である。The fact is that D is superior.
本発明における針状晶鉄合金磁性粒子粉末は、１４００
０ｅ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 has a 1400
It has a high coercive force of 0e or more.
本発明における針状晶鉄合金磁性粒子粉末は、１３０
ｅｍｕ／ｇ以上という大きな飽和磁化を有する。The acicular iron alloy magnetic particle powder in the present invention is 130
It has a large saturation magnetization of emu/g or more.
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 of 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 particle powder in the present invention is 0.50
It has the following excellent S, F, and D values.
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。Having high coercive force and large saturation magnetization in the present invention,
In addition, it has excellent oxidation stability, and is S and 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。Acicular iron alloy magnetic particles having an excellent D are as follows: As shown in the comparative example below, when the starting material particles are coated only with a boron compound, when the starting material particles are coated only with a cobalt compound, the starting material particles are coated with a cobalt compound only. It cannot be obtained either when boron or cobalt or both of these elements are contained in the particles, and it can only be obtained 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, various 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ｐＨ１１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ＦｅＣＯ５を含む懸濁液に酸素含有ガ
スを通気して酸化反応を行う方法等のいずれの方法によ
っても得ることができ、長袖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、、ＡＩ、 Ｍｎ５Ｃ
ｕ等の金属イオンを存在させてもよい。The acicular goethite particles of the present invention are obtained by mixing a well-known ferrous salt aqueous solution and an equivalent or more alkaline solution, and preparing a suspension containing ferrous hydroxide particles at a pH of 11 or higher and a temperature of 80°C or lower. A method of carrying out an oxidation reaction by passing an oxygen-containing gas through a temperature of Particles having a long sleeve length 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 above goethite production reaction, Ni, Zn, AI, Mn5C, which are usually added to improve the properties of the target acicular iron alloy magnetic particle powder, are added.
Metal ions such as u may also 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、ｌＯ：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。In order for the acicular iron alloy magnetic particles to have preferable S, F, and D, especially 0.47 or less, the particle size obtained by the latter method must be uniform and do not contain dendritic particles. Acicular goethite particles may be used as starting material particles. In particular, particles with a uniform particle size and a long axis diameter of 0.18 to 0.3 μm with no dendritic particles mixed in, and a large axial ratio (long axis: short axis), especially lO:1 or more. When acicular goethite particles are used as the starting material particles, it is possible to obtain acicular iron alloy magnetic particles having more preferable S, F, and D values, especially 0.44 or less.
本発明における硼素化合物としては、ＫＢ（ｈ、ＬＢＯ
，、）ＩＢＯ！、ＢｔＣｈ等を使用することができる。As the boron compound in the present invention, KB (h, LBO
,,)IBO! , BtCh, etc. can be used.
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攪拌した
後、炉別、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％以下の場合には、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％以上の場合には、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。Coating of the acicular goethite particles with a boron compound can be carried out by mixing and stirring an aqueous solution containing boron and the acicular goethite particles, followed by heating and drying. The amount of boron compound coated is 1.5 to Fe in terms of B.
It is 10 mol%. If the amount is less than 1.5 mol%, sintering of particles and particles will occur, making it impossible to obtain acicular iron alloy magnetic particles having a high coercive force; if it is more than 10 mol%, , it becomes 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攪拌した後、ｐ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。As the cobalt compound in the present invention, cobalt sulfate, cobalt nitrate, cobalt acetate, cobalt chloride, etc. can be used. Coating of the acicular goethite particles with a cobalt compound can be carried out by mixing and stirring an aqueous solution containing cobalt and the acicular goethite particles, and then separating the mixture with p and drying. The amount of the cobalt compound coated is 1.5 to 10 mol % based on Fe in terms of Co.
１．５モル％以下の場合には、飽和磁化が１３０ ｅ＋
ｍｕ／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。If it is 1.5 mol% or less, the saturation magnetization is 130 e+
Mu/g or less, S, F, and D are 0.50 or more, making it impossible to obtain the acicular iron alloy magnetic particles that are the object of the present invention.
１０モル％以上の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。Although it is possible to obtain the acicular iron alloy magnetic particles which are the object of the present invention when the content is 10 mol % or more, 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 particle surfaces of the acicular goethite particles may be coated with the boron compound and the cobalt compound in either order or at the same time.
本発明における加熱焼成温度は、３００〜６００’Ｃで
ある。３００℃以下である場合には、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、［１，を０
．５以下とすることが出来ない。The heating and firing temperature in the present invention is 300 to 600'C. If the temperature is below 300°C, it is difficult to increase the density of the particles, so the shape of the particles cannot be maintained during heating in the subsequent reduction process, and the coercive force of the acicular iron alloy magnetic particles decreases. Also, S, F, [1, becomes 0
．． It cannot be lower than 5.
Ｓ、Ｐ、Ｄ、が改良されない理由について、加熱焼成温
度が３００℃以下である場合には、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。６０
０℃以上である場合には、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 reason why S, P, and D are not improved is that if the firing temperature is 300°C or lower, recrystallization becomes insufficient, resulting in nonuniform shape anisotropy due to the shape distribution of particles after reduction. It is thought that this causes non-uniform crystal anisotropy due to oxidation and structural distribution of Fe, B, and Co. 60
If the temperature is 0° C. or higher, sintering occurs between particles and particles, and the shape of the particles collapses.
本発明における加熱還元温度は、３００〜５００℃であ
る。３００℃以下である場合には、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″Ｃ以上である場合に
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 heating reduction temperature in the present invention is 300 to 500°C. If the temperature is 300° C. or lower, the reduction reaction is insufficient and it is impossible to obtain acicular iron alloy magnetic particles having large saturation magnetization. If the temperature is 500''C or more, sintering occurs between particles and particles, and the shape of the particles is distorted, so that 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、
長袖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 particle powder obtained in the present invention is
Long sleeves 0.1~0.4μm, axis ratio (long axis: short axis) 5:1~
The range is 15:1.
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 acicular iron alloy magnetic particles powder after thermal reduction in the present invention can be obtained by a well-known method, for example, by immersing the powder in an organic solvent such as toluene, and after replacing the atmosphere after reduction with an inert gas. It can be taken out into the air by gradually increasing the oxygen content in it and finally slowly oxidizing it with air.
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、「振動試料磁力径ＶＳＭ−３Ｓ−１５Ｊ （東
英工業■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’Ｃ，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。In addition, the long axis and axial ratio (long axis: short axis) of particles in the following Examples and Comparative Examples are shown as average values of numerical values measured from electron micrographs. The magnetic properties of the acicular iron alloy magnetic particles were measured using a vibrating sample magnetic force diameter VSM-3S-15J (manufactured by Toei Kogyo ■) and applying an external magnetic field of up to 10 KOe. 'C, relative humidity 90
Saturation magnetization reduction rate (%) after being left for 7 days in an atmosphere of %
). S, F, and D were measured by using a sheet-like sample piece with a square shape of 0.85 obtained by the following method, and using the differential circuit of the magnetic measuring instrument to obtain a differential curve of coercive force. , by measuring the half width of this curve and dividing this value by the coercive force at the peak value of the curve.
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２５Ｊ！ｍ
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、３〜５
ＫＧａｕｓｓの磁場中で乾燥させ−ることにより得た
。The sheet-like sample piece was prepared by putting the following ingredients into a 100 cc polyethylene bottle in the proportions shown below, and then mixing and dispersing the mixture in a Red Devil for 8 hours to form a 25 J! thick magnetic paint. m
of polyethylene terephthalate film using an applicator to a thickness of 50 μm, and then
Obtained by drying in a K Gauss magnetic field.
３Ｉφスチールボール 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 ８
３．３重量部く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
長袖０．２１μｍ、軸比（長軸：短軸）１２：１の針状
晶ゲータイト粒子１００ｇを１１の水中に懸濁させた。3Iφ 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 8
3.3 parts by weight Production of needle-like hematite particles> Examples 1 to 10 Comparative Examples 1 to 9; Example 1 Needle crystals with long sleeves of 0.21 μm and axial ratio (long axis: short axis) of 12:1 100 g of goethite particles were suspended in 11 water.
上記懸濁液にＨＪＯｓ １０．０ ｇ （針状晶ゲータ
イト粒子に対して１０．０ｗｔ％に該当する。）及びＣ
ｏ （ＣＨｓｃＯｏ） ！・４ＨｚＯ１３，Ｏｇ （針
状晶ゲータイト粒子に対して１３．０ｗｔ％に該当する
。）を添加して１０分間攪拌した。この時の懸濁液のｐ
Ｈは６．２であった。10.0 g of HJOs (corresponding to 10.0 wt% with respect to the acicular goethite particles) and C were added to the above suspension.
o (CHscOo)! -4HzO13,0g (corresponding to 13.0 wt% with respect to the acicular goethite particles) was added and stirred for 10 minutes. p of the suspension at this time
H was 6.2.
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ｐ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−ＦｅＯＯ）
１粒子を得た。Then, after adjusting the pH of the suspension to 9.3 by adding NH4OH, the acicular α-FeOOH particles were separated and dried to obtain acicular α-FeOOH particles coated with boron and cobalt.
One particle was obtained.
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’Ｃ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、平均値で長袖０．１９μｍ１軸比（長軸
：短軸）１１：１であった。50 g of the acicular goethite particles coated with boron and cobalt were heat-treated in air at 400'C to obtain acicular hematite particles coated with boron oxide and cobalt oxide. . As a result of electron micrograph observation, the particles had an average value of 0.19 μm and a uniaxial ratio (long axis: short axis) of 11:1.
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 Types of acicular goethite particles, types of boron compounds,
Acicular hematite particles were obtained in the same manner as in Example 1, except that the amount and period of presence, the type, amount and period of cobalt compound, and the temperature in the heating and firing step were varied.
この時の主要製造条件及び緒特性を表１に示す。Table 1 shows the main manufacturing conditions and characteristics at this time.
〈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 particles> 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 particle powder was reduced at 410° C. for 6 hours in a hydrogen stream 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。The acicular iron alloy magnetic particles obtained by reduction were coated with a stable oxide film on the surface of the particles to prevent rapid oxidation when taken out into the air.
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Ｐｅ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、長袖０．１５μｍ、軸比（長軸：短軸）７：
１であった。磁気特性は、保磁力Ｈｅが１５３００ｅ
、飽和磁化σＳが１３３ ｅｍｕ／ｇであり、酸化安定
性は８．０％、Ｓ、Ｆ、Ｄ、は０．４３であった。As a result of fluorescent X-ray analysis, the obtained acicular iron alloy magnetic particles contained 4.7 mol% of B based on Fe and 4.5 mol% of CO based on Pe, and As a result of electron microscope observation, the long sleeve is 0.15 μm, and the axial ratio (long axis: short axis) is 7:
It was 1. As for the magnetic properties, the coercive force He is 15300e.
, saturation magnetization σS was 133 emu/g, oxidation stability was 8.0%, and S, F, and D were 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１
１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 1 except that the type of acicular hematite particle powder and the temperature and time in the thermal reduction step were variously changed.
Acicular iron alloy magnetic particles were obtained in the same manner as in Example 1.
この時の主要製造条件及び緒特性を表２に示す。Table 2 shows the main manufacturing conditions and 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
。[Effects of the Invention] As shown in the examples above, the acicular iron alloy magnetic particles according to the present invention have a high coercive force and a large saturation magnetization,
In addition, the powder particles have excellent oxidation stability and are excellent in S, F, and D, so they are suitable as magnetic particles for high-density recording and high-output applications, which are currently most in demand.
Claims (2)
、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) Contains boron and cobalt near the particle surface, and contains S. F. D. An acicular iron alloy magnetic particle powder for magnetic recording comprising acicular iron alloy magnetic particles having a particle size of 0.50 or less.
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３５０〜５００℃の温度範囲で
加熱還元することを特徴とする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０．５
０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の製造法。(2) The surface of the acicular goethite particles is coated with a boron compound and a cobalt compound, and then heat-treated in a temperature range of 300 to 600°C to form acicular goethite particles coated with boron oxide and cobalt oxide. Crystalline hematite particles are obtained, and then the acicular hematite particles are heated and reduced in a temperature range of 350 to 500°C. F. D. is 0.5
A method for producing acicular iron alloy magnetic particles for magnetic recording comprising acicular iron alloy magnetic particles having a particle size of 0 or less.
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 |
| 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. |
| EP89308004A EP0379776B1 (en) | 1989-01-27 | 1989-08-07 | Acicular magnetic iron based alloy particles for magnetic recording and method of producing the same |
| 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 true JPH02197503A (en) | 1990-08-06 |
| JP2767048B2 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) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5167250A (en) * | 1974-12-09 | 1976-06-10 | Fuji Photo Film Co Ltd | |
| JPS55161007A (en) * | 1979-05-31 | 1980-12-15 | Toda Kogyo Corp | Production of needle-like crystalline 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
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5167250A (en) * | 1974-12-09 | 1976-06-10 | Fuji Photo Film Co Ltd | |
| JPS55161007A (en) * | 1979-05-31 | 1980-12-15 | Toda Kogyo Corp | Production of needle-like crystalline 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 |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2767048B2 (en) | 1998-06-18 |
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