JPH06279803A - Metallic powder for magnetic recording and production thereof - Google Patents
Metallic powder for magnetic recording and production thereofInfo
- Publication number
- JPH06279803A JPH06279803A JP5069573A JP6957393A JPH06279803A JP H06279803 A JPH06279803 A JP H06279803A JP 5069573 A JP5069573 A JP 5069573A JP 6957393 A JP6957393 A JP 6957393A JP H06279803 A JPH06279803 A JP H06279803A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic recording
- silicone resin
- metal powder
- thermosetting silicone
- saturation magnetization
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000000843 powder Substances 0.000 title claims abstract description 50
- 238000004519 manufacturing process Methods 0.000 title claims description 6
- 239000002245 particle Substances 0.000 claims abstract description 37
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 28
- 229920002050 silicone resin Polymers 0.000 claims abstract description 27
- 229920001187 thermosetting polymer Polymers 0.000 claims abstract description 27
- 230000005415 magnetization Effects 0.000 claims abstract description 26
- 238000010438 heat treatment Methods 0.000 claims abstract description 18
- 239000002904 solvent Substances 0.000 claims abstract description 17
- 229910052742 iron Inorganic materials 0.000 claims abstract description 12
- 239000011248 coating agent Substances 0.000 claims abstract description 10
- 238000000576 coating method Methods 0.000 claims abstract description 10
- 239000012298 atmosphere Substances 0.000 claims abstract description 6
- 229910052751 metal Inorganic materials 0.000 claims description 49
- 239000002184 metal Substances 0.000 claims description 49
- 229910052598 goethite Inorganic materials 0.000 claims description 12
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 claims description 12
- 230000001590 oxidative effect Effects 0.000 claims description 8
- 239000011019 hematite Substances 0.000 claims description 5
- 229910052595 hematite Inorganic materials 0.000 claims description 5
- 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 description 5
- 238000001354 calcination Methods 0.000 claims description 2
- 239000002923 metal particle Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 claims 1
- 238000007254 oxidation reaction Methods 0.000 abstract description 17
- 230000003647 oxidation Effects 0.000 abstract description 14
- 239000013528 metallic particle Substances 0.000 abstract 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 22
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 12
- 229910052757 nitrogen Inorganic materials 0.000 description 11
- 238000006722 reduction reaction Methods 0.000 description 8
- 239000007789 gas Substances 0.000 description 7
- 239000006247 magnetic powder Substances 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 239000012299 nitrogen atmosphere Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 229910018557 Si O Inorganic materials 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- JZQOJFLIJNRDHK-CMDGGOBGSA-N alpha-irone Chemical compound CC1CC=C(C)C(\C=C\C(C)=O)C1(C)C JZQOJFLIJNRDHK-CMDGGOBGSA-N 0.000 description 1
- 239000003849 aromatic solvent Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- -1 dimethylsiloxane Chemical class 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 150000002430 hydrocarbons Chemical group 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 238000011835 investigation Methods 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
- 150000002576 ketones Chemical class 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- BFXIKLCIZHOAAZ-UHFFFAOYSA-N methyltrimethoxysilane Chemical compound CO[Si](C)(OC)OC BFXIKLCIZHOAAZ-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 125000005372 silanol group Chemical group 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 1
- CPUDPFPXCZDNGI-UHFFFAOYSA-N triethoxy(methyl)silane Chemical compound CCO[Si](C)(OCC)OCC CPUDPFPXCZDNGI-UHFFFAOYSA-N 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は高密度磁気記録媒体用の
磁性粉として用いられる、微細で飽和磁化量が高く、酸
化安定性に優れた磁気記録用金属粉末およびその製造法
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine magnetic powder for magnetic recording, which is used as a magnetic powder for a high density magnetic recording medium, has a high saturation magnetization and is excellent in oxidation stability, and a method for producing the same. .
【０００２】[0002]
【従来の技術及び発明が解決しようとする課題】高密度
磁気記録媒体用の金属粉末として、鉄を主成分とする磁
気記録用金属粉末の開発が進められ、オーディオテー
プ、ビデオ用テープ、フロッピーディスク等に利用され
ている。磁気記録用金属粉末の現在実用化されている一
般的な製造法は、鉄を主体とする、例えば針状あるいは
紡錘状のα−オキシ水酸化鉄あるいは酸化鉄を還元性ガ
ス中で加熱還元して、金属あるいは合金の粉末とした
後、粒子表面に薄い酸化皮膜を形成させる方法である。
一方、近年、磁気記録再生装置の小型軽量化、高画質
化、長時間化が進められ、それに伴い使用する磁気記録
媒体の高密度化が強く要望されている。磁気記録媒体の
高密度化を達成するためには、使用する磁気記録用金属
粉末が、微細粒子であり、保磁力が高く、飽和磁化量が
大きく、酸化安定性にも優れる必要がある。しかるに、
最近の高密度記録化に伴う、より短波長での記録再生の
必要性から、磁気記録用金属粉末の粒子の長さはより短
いもの、特に 0.2μｍ以下の長軸長、Ｘ線粒径(D110)が
160Å以下の微細な粒子サイズの磁気記録用金属粉末が
要望され、また磁気記録再生ヘッドの改良が進められ
て、保磁力がより高いもの、特に保磁力が1700Ｏｅ以上
のものが要望されている。ここで、粒子の長軸長が短い
ものでも粒子の太さがより小さく、軸比を大きくできる
ならば、保磁力を高くすることが可能であるが、粒子の
太さを小さくすることには限界がある。これは、一つに
は粒子があまり細くなると、超常磁性が発現して保磁力
を示さないことであり、二つめには金属粉末には大気中
で安全に取り扱えるようにするために粒子の表面に酸化
被膜を形成しているため粒子の太さを小さくするに従い
酸化被膜の占める割合が多くなり、結果として金属部の
占める割合が少なくなり、磁性を示さなくなってしまう
からである。又、飽和磁化量も記録再生の出力の面から
より高いもの、特に飽和磁化量135emu/g以上が望まれて
いる。しかしながら、磁気記録用金属粉末の酸化安定性
（高温、高湿下での飽和磁化量の経時変化）は、酸化被
膜の緻密さや粒子の表面に被覆する形状保持剤の種類、
核となる合金の種類によって変化するが、一般に粒子が
微細になり表面積が大きくなるにつれ、飽和磁化量は小
さくなり、また磁化能力の経時変化は大きくなるという
問題があった。以上の如く、近年の磁気記録再生装置の
高性能化に伴い、使用する磁気記録媒体の高出力化、低
ノイズ化の要望が強く、使用する磁気記録用金属粉末も
微細で、保磁力が高く、飽和磁化量の大きく、酸化安定
性に優れるものが望まれている。しかしながら、従来の
技術では、これら要望の全てを満足するような磁気記録
用金属粉末は得られていない。本発明はこの問題点を解
決することを目的とし、長軸が 0.2μｍ以下、軸比が５
〜10であり、かつ保磁力が1700Ｏｅ以上、飽和磁化量が
135emu/g以上、Ｘ線粒径（D110) が 160Å以下の磁気記
録用金属粉末を提供することを目的とするものである。2. Description of the Related Art As a metal powder for high density magnetic recording media, development of metal powder for magnetic recording containing iron as a main component has been promoted, and audio tape, video tape, floppy disk. It is used for etc. A general production method of metal powders for magnetic recording currently in practical use is mainly iron, for example, needle-shaped or spindle-shaped α-iron oxyhydroxide or iron oxide is heated and reduced in a reducing gas. Then, after forming a powder of metal or alloy, a thin oxide film is formed on the particle surface.
On the other hand, in recent years, miniaturization and weight reduction of a magnetic recording / reproducing apparatus, improvement in image quality, and prolongation of time have been advanced, and accordingly, high density of a magnetic recording medium used has been strongly demanded. In order to achieve a high density of the magnetic recording medium, the magnetic recording metal powder to be used must be fine particles, have a high coercive force, a large saturation magnetization amount, and be excellent in oxidation stability. However,
Due to the need for recording / reproducing at shorter wavelengths accompanying the recent trend toward higher density recording, the length of the particles of the magnetic powder for magnetic recording is shorter, especially the long axis length of 0.2 μm or less D 110 )
A metal powder for magnetic recording having a fine particle size of 160 Å or less is desired, and a magnetic recording / reproducing head is being improved, and a coercive force higher, particularly a coercive force of 1700 Oe or more is desired. Here, even if the major axis length of the particles is short, if the particle thickness is smaller and the axial ratio can be increased, the coercive force can be increased, but it is not possible to reduce the particle thickness. There is a limit. This is because, if the particles become too thin, superparamagnetism develops and they do not exhibit coercive force. Secondly, the surface of the particles should be treated so that the metal powder can be safely handled in the atmosphere. The reason is that since the oxide film is formed on the surface, the ratio of the oxide film increases as the particle thickness is reduced, and as a result, the ratio of the metal part decreases and the magnetism is not exhibited. Further, it is desired that the saturation magnetization amount is higher from the aspect of recording / reproducing output, particularly, the saturation magnetization amount of 135 emu / g or more. However, the oxidative stability of metal powder for magnetic recording (change of saturation magnetization at high temperature and high humidity over time) depends on the denseness of the oxide film and the type of shape-retaining agent coated on the surface of the particles.
Although it varies depending on the type of alloy serving as the nucleus, there is a problem that the amount of saturation magnetization becomes smaller and the change over time of the magnetizing ability becomes larger as the particles become finer and the surface area increases. As described above, with the high performance of magnetic recording / reproducing devices in recent years, there is a strong demand for higher output and lower noise of the magnetic recording medium used, the metal powder for magnetic recording used is also fine, and the coercive force is high. What has a large saturation magnetization and is excellent in oxidation stability is desired. However, the conventional technology has not obtained a metal powder for magnetic recording that satisfies all of these demands. The present invention aims to solve this problem, and the major axis is 0.2 μm or less and the axial ratio is 5 μm.
~ 10, coercive force of 1700 Oe or more, saturation magnetization
It is an object of the present invention to provide a metal powder for magnetic recording having an X-ray particle size (D 110 ) of 135 emu / g or more and 160 Å or less.
【０００３】[0003]
【課題を解決するための手段】本発明者等は上記目的を
達成すべく種々の検討を行った結果、磁気記録用金属粉
末の粒子表面を熱硬化性シリコーン樹脂もしくはその焼
成物で被覆することが有効であることを見出し、本発明
を完成するに到ったものである。即ち、本発明は、例え
ば針状もしくは紡錘状のゲーサイト粒子または該ゲーサ
イト粒子を加熱焼成して得られたヘマタイト粒子を還元
性ガスで加熱還元し、鉄を主体とする金属粉末を得、し
かる後、前記金属粉末を熱硬化性シリコーン樹脂と溶剤
中で接触させ、次いで非酸化性雰囲気下で溶剤を除去
し、さらに加熱焼成し前記金属粉末表面を前記熱硬化性
シリコーン樹脂もしくはその焼成物で被覆し、その後徐
酸化するという方法を採用したことにより、徐酸化時に
形成する磁気記録用金属粉末の粒子の酸化被膜の占める
割合を少なくし、金属部の占める割合を増すことがで
き、その結果、磁気記録用金属粉末の飽和磁化量が大き
くなり、また緻密な熱硬化性シリコーン樹脂もしくはそ
の焼成物で被覆するため、酸化安定性にも優れる磁気記
録用金属粉末を得ることを可能にしたものである。Means for Solving the Problems As a result of various investigations by the inventors of the present invention, the surface of particles of magnetic recording metal powder is coated with a thermosetting silicone resin or a fired product thereof. Have been found to be effective, and have completed the present invention. That is, the present invention, for example, heat-reducing needle-shaped or spindle-shaped goethite particles or hematite particles obtained by heating and firing the goethite particles with a reducing gas to obtain a metal powder mainly composed of iron, Thereafter, the metal powder is brought into contact with a thermosetting silicone resin in a solvent, then the solvent is removed in a non-oxidizing atmosphere, and the mixture is further heated and baked to make the surface of the metal powder the thermosetting silicone resin or a baked product thereof. By adopting a method of coating with, followed by gradual oxidation, the proportion of the oxide film of the particles of the magnetic recording metal powder formed during gradual oxidation can be reduced and the proportion of the metal part can be increased. As a result, the saturation magnetization of the magnetic powder for magnetic recording increases, and since it is coated with a dense thermosetting silicone resin or its fired product, it has excellent oxidation stability. In which it made it possible to obtain a use metal powder.
【０００４】以下、本発明の磁気記録用金属粉末及びそ
の製造法を詳細に説明する。The metal powder for magnetic recording of the present invention and the method for producing the same will be described in detail below.
【０００５】本発明の磁気記録用金属粉末の出発原料
は、ゲーサイト粒子または該ゲーサイト粒子を加熱焼成
して得られたヘマタイト粒子であり、その形状は特に限
定されないが、針状もしくは紡錘状のものが好ましい。
例えば、第一鉄塩溶液と炭酸アルカリ溶液または水酸化
アルカリ溶液を非酸化性雰囲気下、混合した後、酸化性
ガスを吹き込むことにより、長軸長0.24μｍ以下、軸比
７〜13の針状もしくは紡錘状のゲーサイトを得ることが
できる。又、このゲーサイトに表面処理を施し、必要に
より 300〜600 ℃の温度で加熱処理しヘマタイトとすれ
ばよい。また上記出発原料には、必要により磁気記録用
金属粉末の諸特性を向上させるために使用されるAl、S
i、B 、P 、Ni、CO、Mn、Cu、Zn、Cr、Mg、Ca、Sr、B
a、希土類元素等のFe以外の元素を存在させることがで
きる。次いで、上記ゲーサイト粒子またはヘマタイト粒
子を、常法により水素ガス等の還元性ガスで加熱還元し
て鉄を主成分とする金属粉末を得る。ここで、加熱還元
温度は 300〜600 ℃、好ましくは 400〜500 ℃で行うこ
とができる。 300℃未満の場合には還元反応が遅く還元
時間に長時間を必要とし経済的でないし、 600℃を超え
る場合には粒子の焼結が起こりやすい。The starting material of the metal powder for magnetic recording of the present invention is goethite particles or hematite particles obtained by heating and calcining the goethite particles, and the shape thereof is not particularly limited, but is needle-like or spindle-like. Are preferred.
For example, a ferrous salt solution and an alkali carbonate solution or an alkali hydroxide solution are mixed in a non-oxidizing atmosphere, and then an oxidizing gas is blown into the solution so that the major axis length is 0.24 μm or less and the axial ratio is 7 to 13 Alternatively, spindle-shaped goethite can be obtained. Further, this goethite may be surface-treated and, if necessary, may be heat-treated at a temperature of 300 to 600 ° C to obtain hematite. Further, the above starting materials include Al and S which are used to improve various properties of the magnetic recording metal powder, if necessary.
i, B, P, Ni, CO, Mn, Cu, Zn, Cr, Mg, Ca, Sr, B
Elements other than Fe, such as a and rare earth elements, can be present. Next, the goethite particles or hematite particles are heated and reduced with a reducing gas such as hydrogen gas by a conventional method to obtain a metal powder containing iron as a main component. Here, the heat reduction temperature can be 300 to 600 ° C, preferably 400 to 500 ° C. When the temperature is lower than 300 ° C, the reduction reaction is slow and the reduction time requires a long time, which is not economical, and when the temperature is higher than 600 ° C, sintering of particles tends to occur.
【０００６】次に、得られた鉄を主成分とする金属粉末
を熱硬化性シリコーン樹脂と溶剤中で接触させ、次いで
非酸化性雰囲気下で例えば80〜120 ℃の温度で溶剤を除
去し、さらに150 〜450 ℃の温度で加熱焼成して前記金
属粒子表面を前記熱硬化性シリコーン樹脂もしくはその
焼成物で被覆する。本発明に使用される熱硬化性シリコ
ーン樹脂としては、溶剤に可溶で主鎖がSi-Oの三次元立
体構造で、末端に水酸基を有し、加熱により脱水縮合
し、高分子化するものであれば良い。例えば次の一般式
で表される熱硬化性シリコーン樹脂等である。Next, the obtained iron-based metal powder is contacted with a thermosetting silicone resin in a solvent, and then the solvent is removed under a non-oxidizing atmosphere at a temperature of 80 to 120 ° C., for example. Further, it is heated and baked at a temperature of 150 to 450 ° C. to coat the surface of the metal particles with the thermosetting silicone resin or the baked product thereof. The thermosetting silicone resin used in the present invention is one that is soluble in a solvent, has a three-dimensional structure of Si-O in the main chain, has a hydroxyl group at the terminal, and is dehydrated and condensed by heating to be polymerized. If it is good. For example, it is a thermosetting silicone resin represented by the following general formula.
【０００７】[0007]
【化１】 [Chemical 1]
【０００８】（式中、R1〜R9は炭素数１〜10の炭化水素
基である） 本発明では、上記構造のものを 150〜450 ℃で加熱する
ことにより、反応性を持つシラノール基を脱水縮合さ
せ、高分子化し、磁気記録用金属粉末表面に被膜を形成
させる。加熱温度が 150℃未満の場合には熱硬化性シリ
コーン樹脂の硬化反応に長時間を要し、また得られる熱
硬化性シリコーン樹脂被膜の緻密性に劣り、徐酸化時に
均一な酸化被膜を得ることができない。また加熱温度が
450℃を越える場合には鉄を主成分とする磁気記録用金
属粉末の金属結晶部分が加熱によって成長し、Ｘ線粒径
（D110）が大きくなってしまう。上記熱硬化性シリコー
ン樹脂には、架橋剤、例えばメチルトリメトキシシラ
ン、テトラメトキシシラン、メチルトリエトキシシラン
等を存在させ、架橋密度を高めることもできる。使用す
る溶剤の種類としてはトルエン等の芳香族系の溶剤、メ
チルエチルケトン等のケトン系の溶剤、メタノール等の
アルコール系の溶剤等が使用でき、熱硬化性シリコーン
樹脂の可溶性、反応性等の性質にあわせ適宜選択でき
る。樹脂被覆量としては熱硬化性シリコーン樹脂もしく
はその焼成物の被覆量が鉄を 100としての重量比で３〜
10wt％であることが望ましい。被覆量が３wt％未満の場
合、被膜の強さが十分といえず、飽和磁化量を高くする
ことができないし、十分な酸化安定性を得ることができ
ない。また被覆量が10wt％を超える場合には、非磁性部
分の占める割合が多くなり、飽和磁化量を高くすること
ができないし、また粒子同志の癒着を引き起こす。(Wherein R 1 to R 9 are hydrocarbon groups having 1 to 10 carbon atoms) In the present invention, a silanol group having reactivity is obtained by heating the above structure at 150 to 450 ° C. Is dehydrated and condensed to be polymerized to form a film on the surface of the magnetic powder for magnetic recording. If the heating temperature is less than 150 ° C, the curing reaction of the thermosetting silicone resin will take a long time, and the resulting thermosetting silicone resin coating will be inferior in denseness, and a uniform oxide coating will be obtained during slow oxidation. I can't. In addition, the heating temperature
If the temperature exceeds 450 ° C., the metal crystal part of the magnetic recording metal powder containing iron as a main component grows by heating, and the X-ray grain size (D 110 ) becomes large. A cross-linking agent such as methyltrimethoxysilane, tetramethoxysilane, and methyltriethoxysilane may be present in the thermosetting silicone resin to increase the crosslink density. As the type of solvent to be used, an aromatic solvent such as toluene, a ketone solvent such as methyl ethyl ketone, an alcohol solvent such as methanol, or the like can be used, and the properties such as solubility and reactivity of the thermosetting silicone resin can be used. It can be selected as appropriate. As for the resin coating amount, the coating amount of the thermosetting silicone resin or its fired product is 3 to 3 by weight ratio with iron as 100.
It is preferably 10 wt%. If the coating amount is less than 3 wt%, the strength of the coating cannot be said to be sufficient, the saturation magnetization amount cannot be increased, and sufficient oxidation stability cannot be obtained. On the other hand, when the coating amount exceeds 10 wt%, the non-magnetic portion occupies a large proportion, the saturation magnetization cannot be increased, and the particles are cohered with each other.
【０００９】以上の様にして得た熱硬化性シリコーン樹
脂もしくはその焼成物で被覆された金属粉末を徐酸化
し、空気中でも取り扱える磁気記録用金属粉末を得る。
このようにして得られた本発明の磁気記録用金属粉末の
性状は、長軸長が 0.2μｍ以下で、軸比が５〜10であ
り、かつ保磁力が1700Ｏｅ以上、飽和磁化量が135emu/g
以上、Ｘ線粒径（D110）が160 Å以下である。The metal powder coated with the thermosetting silicone resin or the fired product thereof is gradually oxidized to obtain a magnetic recording metal powder that can be handled even in air.
The properties of the metal powder for magnetic recording of the present invention thus obtained are such that the major axis length is 0.2 μm or less, the axial ratio is 5 to 10, the coercive force is 1700 Oe or more, and the saturation magnetization is 135 emu / g
As described above, the X-ray particle size (D 110 ) is 160 Å or less.
【００１０】[0010]
【作用および効果】本発明の第一の効果は磁気記録用金
属粉末の酸化被膜の占める割合を少なくし、高い飽和磁
化量を磁気記録用金属粉末に付与できることである。従
来の技術では酸化被膜を直接もしくは有機溶剤中で、空
気もしくは希釈した空気中の酸素で酸化することで形成
する。この時磁気記録用粉末は非常に酸化され易く、酸
化反応時に発熱を伴う。このため酸素に接した粒子部分
の酸化が局所的に進み、均一な酸化被膜を得ることがで
きず、その結果磁気記録用金属粉末の酸化被膜の占める
割合が多くなり、高い飽和磁化量を磁気記録用金属粉末
に付与できないし、部分的に酸化反応が起こるために粒
子の金属部がちぎれ、磁気記録用金属粉末の軸比が低下
し、高い保磁力を得ることができなかった。本発明では
磁気記録用金属粉末に緻密な熱硬化性シリコーン樹脂も
しくはその焼成物で予め被覆されているため、粒子に部
分的な酸化による発熱が起こりにくく、均一な酸化被膜
を得ることができ、また緻密な熱硬化性シリコーン樹脂
もしくはその焼成物で被覆されているため、酸化反応が
進みにくく、このため酸化被膜を薄くすることができ、
飽和磁化量を大きくすることができる。言い換えれば、
酸化被膜が薄くできるため、高い飽和磁化量を維持しつ
つ、粒子を微細化することができる。FUNCTION AND EFFECT The first effect of the present invention is to reduce the proportion of the oxide film in the magnetic recording metal powder and to impart a high saturation magnetization to the magnetic recording metal powder. In the conventional technique, an oxide film is formed by oxidizing with oxygen in air or diluted air directly or in an organic solvent. At this time, the magnetic recording powder is very easily oxidized, and heat is generated during the oxidation reaction. For this reason, the oxidation of the particle portion in contact with oxygen locally progresses, and a uniform oxide film cannot be obtained. As a result, the ratio of the oxide film in the metal powder for magnetic recording increases, resulting in high saturation magnetization. It could not be applied to the recording metal powder, and the metal portion of the particles was broken due to partial oxidation reaction, the axial ratio of the magnetic recording metal powder was lowered, and high coercive force could not be obtained. In the present invention, since the magnetic recording metal powder is previously coated with a dense thermosetting silicone resin or a fired product thereof, heat generation due to partial oxidation hardly occurs in the particles, and a uniform oxide film can be obtained, In addition, since it is covered with a dense thermosetting silicone resin or its fired product, the oxidation reaction does not proceed easily, and therefore the oxide film can be made thinner.
The saturation magnetization amount can be increased. In other words,
Since the oxide film can be made thin, the particles can be made finer while maintaining a high saturation magnetization amount.
【００１１】第二の効果は緻密な熱硬化性シリコーン樹
脂もしくはその焼成物で粒子が被覆されているため、酸
化されにくく、酸化安定性（高温、高湿下での飽和磁化
量、保磁力の経時変化）が小さくなる。これも緻密な熱
硬化性シリコーン樹脂もしくはその焼成物で粒子が被覆
されているため、酸化されにくく、また磁気記録用金属
粉末の酸化被膜が均一であるためと考えられる。また熱
硬化性シリコーン樹脂もしくはその焼成物は加熱処理
後、溶剤に不溶となるため、磁気記録媒体製造時に使用
される溶剤にも不溶となるため、磁気記録媒体の酸化安
定性も向上する。The second effect is that since the particles are coated with a dense thermosetting silicone resin or a fired product thereof, it is difficult to oxidize, and oxidation stability (saturation magnetization amount under high temperature and high humidity, coercive force Change over time). It is also considered that this is because the particles are coated with a dense thermosetting silicone resin or a fired product thereof, so that it is difficult to oxidize and the oxide film of the magnetic recording metal powder is uniform. Further, since the thermosetting silicone resin or the fired product thereof is insoluble in the solvent after the heat treatment, it is also insoluble in the solvent used at the time of manufacturing the magnetic recording medium, so that the oxidation stability of the magnetic recording medium is also improved.
【００１２】[0012]
【実施例】以下、実施例により本発明を更に詳しく説明
するが、本発明はこれらに限定されるものではない。 実施例１ Feを 100としたときの重量比でCo；５wt％、Ni；３wt
％、Al；５wt％、Si；1.5 wt％を含む長軸長0.24μｍ、
軸比13の紡錘状ゲーサイト110gを窒素気流中600℃で３
時間熱処理し、次いで、水素気流下 470℃の温度で６時
間還元した。還元後、ガスを窒素に変え、温度を室温ま
で下げた後、窒素雰囲気中でジメチルシロキサンシリコ
ーン・メチルシルセスキオキサン共重合体／トルエン溶
液：4.9g（樹脂固形分）／200ml 中に取出し、５時間放
置した。この後トルエンを濾過、分離し、窒素雰囲気
中、加熱炉に試料を入れ、窒素気流下、 120℃で加熱
し、溶剤を除去した。この後さらに 350℃で加熱処理し
樹脂の緻密化を行った。加熱処理後、試料の温度を室温
まで下げた後、窒素気流中に徐々に空気を流して常法に
より安定化処理を行なって長軸長0.16μｍ、軸比10、Si
量5.7 wt％、保磁力1800Ｏｅ、飽和磁化量146emu/g、Ｘ
線粒径 150Åの磁気記録用金属粉末を得た。透過型電子
顕微鏡で観察したところ、型崩れや焼結のない、また樹
脂の剥離や粒子間の癒着のない磁気記録用金属粉末であ
った。磁気記録用金属粉末の温度60℃−相対湿度90％中
での１週間後の保磁力は1790Ｏｅ、飽和磁化量は125emu
/g、角型比は0.502 であった。The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Example 1 Co: 5 wt%, Ni: 3 wt in terms of weight ratio with Fe as 100
%, Al; 5 wt%, Si; 1.5 wt%, long axis length 0.24 μm,
110 g of spindle-shaped goethite with an axial ratio of 13 at 600 ° C in a nitrogen stream
Heat treatment was carried out for an hour, and then reduction was carried out at a temperature of 470 ° C. for 6 hours under a hydrogen stream. After the reduction, the gas was changed to nitrogen, the temperature was lowered to room temperature, and then taken out in a nitrogen atmosphere in a dimethylsiloxane silicone / methylsilsesquioxane copolymer / toluene solution: 4.9 g (resin solid content) / 200 ml, It was left for 5 hours. After that, toluene was filtered and separated, and the sample was put in a heating furnace in a nitrogen atmosphere and heated at 120 ° C. in a nitrogen stream to remove the solvent. After that, heat treatment was further performed at 350 ° C. to densify the resin. After the heat treatment, the temperature of the sample is lowered to room temperature, and then air is gradually passed through the nitrogen stream to stabilize it by a conventional method to obtain a long axis length of 0.16 μm, an axial ratio of 10, Si.
Amount 5.7 wt%, coercive force 1800 Oe, saturation magnetization amount 146 emu / g, X
A metal powder for magnetic recording having a linear particle size of 150Å was obtained. When observed with a transmission electron microscope, it was a metal powder for magnetic recording, which did not lose its shape or sinter, nor did resin peeling or adhesion between particles. The magnetic recording metal powder has a coercive force of 1790 Oe and a saturation magnetization of 125 emu after 1 week in the temperature of 60 ° C.-90% of relative humidity.
/ g, the squareness ratio was 0.502.
【００１３】実施例２〜５ 磁気記録用金属粉末原料、熱処理温度、還元温度、熱硬
化性シリコーン樹脂の種類および添加量を表１の様に種
々変化させた以外は実施例１と同様な手法で行った。こ
の時の磁気記録用金属粉末の性状、磁気特性および温度
60℃−相対湿度90％中での１週間後の保磁力、飽和磁化
量を表２に示した。Examples 2 to 5 The same procedure as in Example 1 except that the raw material of magnetic powder for magnetic recording, the heat treatment temperature, the reduction temperature, the type of thermosetting silicone resin and the addition amount thereof were changed as shown in Table 1. I went there. At this time, the properties, magnetic properties and temperature of the magnetic recording metal powder
Table 2 shows the coercive force and saturation magnetization after one week at 60 ° C.-90% relative humidity.
【００１４】比較例１ Feを 100としたときの重量比でCo；８wt％、Ni；３wt
％、Al；３wt％、Si；３wt％を含む長軸長 2.0μｍ、軸
比12の紡錘状ゲーサイト110gを窒素気流中 600℃で３時
間熱処理し、次いで、水素気流下 470℃の温度で６時間
還元した。還元後、ガスを窒素に変え、温度を室温まで
下げた後、窒素気流中に徐々に空気を流して常法により
安定化処理を行って磁気記録用金属粉末を得た。磁気記
録用金属粉末の性状、磁気特性および温度60℃−相対湿
度90％中での１週間後の保磁力、飽和磁化量を表２に示
した。Comparative Example 1 Co: 8 wt%, Ni: 3 wt in terms of weight ratio when Fe is 100.
%, Al: 3 wt%, Si: 3 wt%, long axis length 2.0 μm, axial ratio of 12 spindle-shaped goethite 110 g was heat-treated in a nitrogen stream at 600 ° C. for 3 hours, then in a hydrogen stream at a temperature of 470 ° C. Reduced for 6 hours. After the reduction, the gas was changed to nitrogen, the temperature was lowered to room temperature, and then air was gradually passed in a nitrogen stream to carry out a stabilization treatment by a conventional method to obtain a magnetic recording metal powder. Table 2 shows the properties of the metal powder for magnetic recording, the magnetic properties, and the coercive force and saturation magnetization after one week at a temperature of 60 ° C. and a relative humidity of 90%.
【００１５】比較例２ Feを 100としたときの重量比でCo；８wt％、Ni；３wt
％、Al；３wt％、Si；３wt％を含む長軸長 2.0μｍ、軸
比12の紡錘状ゲーサイト110gを窒素気流中 600℃で３時
間熱処理し、次いで、水素気流下 470℃の温度で６時間
還元した。還元後、ガスを窒素に変え、温度を室温まで
下げた後、窒素雰囲気中で、トルエン溶液：200ml 中に
取出し、５時間放置した。この後窒素雰囲気中、加熱炉
に試料を入れ、窒素気流下、 120℃で加熱し、溶剤を除
去した。この後さらに 350℃で加熱処理した。加熱処理
後、試料の温度を室温まで下げた後、窒素気流中に徐々
に空気を流して常法により安定化処理を行ない磁気記録
用金属粉末を得た。磁気記録用金属粉末の性状、磁気特
性および温度60℃−相対湿度90％中での１週間後の保磁
力、飽和磁化量を表２に示した。Comparative Example 2 Co: 8 wt%, Ni: 3 wt in weight ratio when Fe is 100.
%, Al: 3 wt%, Si: 3 wt%, long axis length 2.0 μm, axial ratio of 12 spindle-shaped goethite 110 g was heat-treated in a nitrogen stream at 600 ° C. for 3 hours, then in a hydrogen stream at a temperature of 470 ° C. Reduced for 6 hours. After the reduction, the gas was changed to nitrogen and the temperature was lowered to room temperature. Then, in a nitrogen atmosphere, the solution was taken out in 200 ml of a toluene solution and left for 5 hours. Then, the sample was put in a heating furnace in a nitrogen atmosphere and heated at 120 ° C. in a nitrogen stream to remove the solvent. After that, heat treatment was further performed at 350 ° C. After the heat treatment, the temperature of the sample was lowered to room temperature, and then air was gradually passed in a nitrogen stream to carry out stabilization treatment by a conventional method to obtain a metal powder for magnetic recording. Table 2 shows the properties of the metal powder for magnetic recording, the magnetic properties, and the coercive force and saturation magnetization after one week at a temperature of 60 ° C. and a relative humidity of 90%.
【００１６】[0016]
【表１】 [Table 1]
【００１７】[0017]
【表２】 [Table 2]
Claims (3)
成物で被覆された、長軸長が 0.2μｍ以下、軸比が５〜
10であり、かつ保磁力が1700Ｏｅ以上、飽和磁化量が13
5emu/g以上、Ｘ線粒径（D110) が 160Å以下であること
を特徴とする鉄を主成分とする磁気記録用金属粉末。1. A major axis length of 0.2 μm or less covered with a thermosetting silicone resin or a fired product thereof, and an axial ratio of 5 to 5.
10, the coercive force is 1700 Oe or more, and the saturation magnetization is 13
A metal powder for magnetic recording containing iron as a main component, which has an X-ray particle size (D 110 ) of 160 Å or less and 5 emu / g or more.
成物の被覆量が鉄を100としての重量比で３〜10wt％で
あることを特徴とする請求項１記載の磁気記録用金属粉
末。2. The metal powder for magnetic recording according to claim 1, wherein the coating amount of the thermosetting silicone resin or the fired product thereof is 3 to 10 wt% based on the weight ratio of iron.
を加熱焼成して得られたヘマタイト粒子を還元性ガスで
加熱還元して鉄を主成分とする金属粉末を得、しかる
後、前記金属粉末を熱硬化性シリコーン樹脂と溶剤中で
接触させ、次いで非酸化性雰囲気下で溶剤を除去し、さ
らに加熱焼成して前記金属粒子表面を前記熱硬化性シリ
コーン樹脂もしくはその焼成物で被覆し、その後徐酸化
することを特徴とする請求項１記載の磁気記録用金属粉
末の製造法。3. A goethite particle or a hematite particle obtained by heating and calcining the goethite particle is heated and reduced with a reducing gas to obtain a metal powder containing iron as a main component. The thermosetting silicone resin is brought into contact with the solvent in a solvent, then the solvent is removed under a non-oxidizing atmosphere, and the material is further heated and baked to coat the surface of the metal particles with the thermosetting silicone resin or the baked product thereof, and then slowly. The method for producing a metal powder for magnetic recording according to claim 1, characterized by oxidizing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5069573A JPH06279803A (en) | 1993-03-29 | 1993-03-29 | Metallic powder for magnetic recording and production thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5069573A JPH06279803A (en) | 1993-03-29 | 1993-03-29 | Metallic powder for magnetic recording and production thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06279803A true JPH06279803A (en) | 1994-10-04 |
Family
ID=13406672
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5069573A Pending JPH06279803A (en) | 1993-03-29 | 1993-03-29 | Metallic powder for magnetic recording and production thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06279803A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009084600A (en) * | 2007-09-27 | 2009-04-23 | Dowa Electronics Materials Co Ltd | Metal magnetic powder, and method for producing the same |
-
1993
- 1993-03-29 JP JP5069573A patent/JPH06279803A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009084600A (en) * | 2007-09-27 | 2009-04-23 | Dowa Electronics Materials Co Ltd | Metal magnetic powder, and method for producing the same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5645652A (en) | Spindle-shaped magnetic iron-based alloy particles containing cobalt and iron as the main ingredients and process for producing the same | |
| JPH0544162B2 (en) | ||
| JP2004319923A (en) | Iron nitride-based magnetic powder | |
| JPH08109401A (en) | Metallic powder for magnetic recording and its production | |
| JPH06279803A (en) | Metallic powder for magnetic recording and production thereof | |
| JP2001081506A (en) | Precursor for producing magnetic powder and ferromagneric metal powder obtained from the same | |
| JP2904225B2 (en) | Method for producing acicular iron alloy magnetic particles for magnetic recording | |
| KR19990077521A (en) | Spindle-shaped goethite particles and process for producing the same | |
| JPH11251122A (en) | Precursor for manufacturing magnetic powder and ferromagnetic metal power obtained from the same | |
| JPS5919964B2 (en) | Method for producing ferromagnetic metal powder | |
| JP3169105B2 (en) | Needle-like alloy magnetic fine particle powder containing iron as a main component and method for producing the same | |
| US5989516A (en) | Spindle-shaped geothite particles | |
| JP3242102B2 (en) | Magnetic powder and method for producing the same | |
| JPS6411577B2 (en) | ||
| JPH03253505A (en) | Production of ferromagnetic metal powder | |
| JP2894495B2 (en) | Manufacturing method of metal magnetic powder for magnetic recording media | |
| JPH08165501A (en) | Fusiform metallic magnetic-grain powder consisting essentially of cobalt and iron and its production | |
| JPH03194905A (en) | Manufacture of magnetic metal powder for magnetic recording | |
| JPH02205601A (en) | Ferromagnetic metal powder | |
| JP3171223B2 (en) | Method for producing acicular magnetic particle powder | |
| JP2805162B2 (en) | Method for producing metal magnetic powder for magnetic recording | |
| JP3001830B2 (en) | Manufacturing method of metal magnetic powder for magnetic recording media | |
| JP3405748B2 (en) | Method for producing metal magnetic powder | |
| JP2000203847A (en) | Cobalt-containing fusiform hematite particulate powder for fusiform magnetic alloy particulate powder predominant in iron and cobalt | |
| JPH07331310A (en) | Production of spindle shaped metallic magnetic particle powder consisting essencially of iron |