JPH03253505A - Production of ferromagnetic metal powder - Google Patents
Production of ferromagnetic metal powderInfo
- Publication number
- JPH03253505A JPH03253505A JP2049325A JP4932590A JPH03253505A JP H03253505 A JPH03253505 A JP H03253505A JP 2049325 A JP2049325 A JP 2049325A JP 4932590 A JP4932590 A JP 4932590A JP H03253505 A JPH03253505 A JP H03253505A
- Authority
- JP
- Japan
- Prior art keywords
- iron
- ferromagnetic metal
- metal powder
- reduction
- fine particles
- 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
- 230000005294 ferromagnetic effect Effects 0.000 title claims abstract description 52
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 48
- 239000002184 metal Substances 0.000 title claims abstract description 48
- 239000000843 powder Substances 0.000 title claims abstract description 20
- 238000004519 manufacturing process Methods 0.000 title claims description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 91
- 229910052742 iron Inorganic materials 0.000 claims abstract description 43
- 150000002736 metal compounds Chemical class 0.000 claims abstract description 7
- 150000002506 iron compounds Chemical class 0.000 claims abstract description 3
- 238000006722 reduction reaction Methods 0.000 claims description 33
- 238000007254 oxidation reaction Methods 0.000 claims description 26
- 230000003647 oxidation Effects 0.000 claims description 25
- 230000005291 magnetic effect Effects 0.000 abstract description 28
- 238000000034 method Methods 0.000 abstract description 15
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 abstract description 13
- 230000001590 oxidative effect Effects 0.000 abstract description 11
- 238000006243 chemical reaction Methods 0.000 abstract description 10
- 239000000463 material Substances 0.000 abstract description 3
- 239000010953 base metal Substances 0.000 abstract 1
- 239000010419 fine particle Substances 0.000 description 31
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 20
- 230000005415 magnetization Effects 0.000 description 19
- 239000007789 gas Substances 0.000 description 15
- 239000002245 particle Substances 0.000 description 12
- 229910001873 dinitrogen Inorganic materials 0.000 description 10
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 9
- 238000005245 sintering Methods 0.000 description 8
- 239000011148 porous material Substances 0.000 description 7
- 238000001816 cooling Methods 0.000 description 6
- 230000006378 damage Effects 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 230000006641 stabilisation Effects 0.000 description 5
- 238000011105 stabilization Methods 0.000 description 5
- 239000007858 starting material Substances 0.000 description 5
- 239000002344 surface layer Substances 0.000 description 5
- 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 4
- 239000007791 liquid phase Substances 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- CUPCBVUMRUSXIU-UHFFFAOYSA-N [Fe].OOO Chemical compound [Fe].OOO CUPCBVUMRUSXIU-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 229910021519 iron(III) oxide-hydroxide Inorganic materials 0.000 description 2
- 239000002923 metal particle Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000012808 vapor phase Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910000531 Co alloy Inorganic materials 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- CZNCTWNLEIFMDX-UHFFFAOYSA-N [Fe].O=O Chemical compound [Fe].O=O CZNCTWNLEIFMDX-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 150000001639 boron compounds Chemical class 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- -1 made of iron Chemical class 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 239000006247 magnetic powder Substances 0.000 description 1
- 239000002075 main ingredient Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000009279 wet oxidation reaction Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、高密度記録に適した磁気記録媒体に於ける磁
性素材としての強磁性金属粉微粒子の製造方法に関する
。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing fine ferromagnetic metal powder particles as a magnetic material in a magnetic recording medium suitable for high-density recording.
磁気テープ、磁気記録媒体として有用な磁性粉末はγ−
酸化鉄が主体であったが、近年ＶＴＲ用や高級オーディ
オ用の高密度記録媒体が望まれるようになり、オキシ水
酸化鉄あるいは酸化鉄を主体とする粉末を還元性ガスに
より気相接触還元して得られる金属鉄や、またはコバル
ト或いはニッケルと鉄との合金を主体とする高い保磁力
を有する磁性金属粉末が用いられる様になってきた。Magnetic powder useful for magnetic tapes and magnetic recording media is γ-
Iron oxide was the main ingredient, but in recent years there has been a demand for high-density recording media for VTRs and high-end audio, so iron oxyhydroxide or iron oxide-based powder is now being reduced in the vapor phase using a reducing gas. Magnetic metal powders having a high coercive force and mainly consisting of metallic iron obtained from the above, or alloys of cobalt or nickel and iron have come to be used.
金属磁性微粒子の保磁力は形状異方性が強い為粒子サイ
ズ、針状性等に依存するが、磁気記録用媒体はオーディ
オ用、ビデオ用を問わず広い記録周波数帯域での高出力
化、低ノイズ化をめざしており、磁性金属粉末としては
その形状は微細化の傾向にあり、尚かつ粉末粒子の細孔
を少なくして飽和磁化を上げること及び塗料用樹脂との
親和性や分散性、塗膜の配向性、充填性も向上する事が
望まれ、バインダー樹脂、各種添加剤の改良及び塗料分
散、媒体加工技術の改良研究も行われている。The coercive force of metal magnetic fine particles has strong shape anisotropy and therefore depends on particle size, acicularity, etc., but magnetic recording media, whether used for audio or video, are capable of achieving high output and low output in a wide recording frequency band. The aim is to reduce noise, and the shape of magnetic metal powder tends to become finer.In addition, we aim to increase saturation magnetization by reducing the pores of powder particles, and improve affinity and dispersibility with paint resins. It is desired to improve the orientation and filling properties of the coating film, and research is also being conducted to improve binder resins, various additives, paint dispersion, and media processing technology.
このような状況において、鉄もしくは鉄化合物を主体と
する金属化合物を出発原料として還元性雰囲気中で加熱
還元し、鉄もしくは鉄を主体とする強磁性金属粉末を得
る為に、いくつかの重要な技術が開発されてきた。例え
ば、還元性雰囲気中で加熱還元により生しる焼結を防止
し原料形状を保持する為に、焼結防止成分としてリン、
珪素、アルミニウム、クロム及びホウ素化合物等を出発
原料である鉄もしくは鉄を主体とした水酸化物もしくは
酸化物に共沈或いは被着した後、還元する方法が知られ
ている。Under these circumstances, several important steps have been taken to obtain iron or iron-based ferromagnetic metal powder by heating and reducing iron or iron-based metal compounds as starting materials in a reducing atmosphere. technology has been developed. For example, in order to prevent sintering that occurs due to thermal reduction in a reducing atmosphere and maintain the shape of the raw material, phosphorus is used as a sintering prevention component.
A method is known in which silicon, aluminum, chromium, boron compounds, etc. are coprecipitated or deposited on a starting material of iron or an iron-based hydroxide or oxide, and then reduced.
通常、還元反応は水素もしくは水素を主体とした還元性
ガスで行われるが、還元初期に還元性ガスに水蒸気を同
伴させ、加熱還元によって得られた鉄もしくは鉄を主体
とした金属の比表面積を低下させる方法（特公昭６ｌ−
３６０４８）が提案されている。又、加熱還元によって
得られた鉄もしくは鉄を主体とした金属はそのままでは
大気中で酸化燃焼してしまうので、大気中で安全に取り
扱う事を可能にし、強磁性金属の酸化が進行する事によ
る磁気特性の経時劣化を防止するための技術は重要であ
る。従来、酸化安定性を確保する手段としては気相接触
反応あるいは液相反応により強磁性金属微粒子表層部に
酸化被膜を形成する方法が知られており、更に酸化安定
性を向上する為に酸化被膜を形成後に高温において加熱
処理する方法（特開昭６ｌ−１５４１１２）、強磁性金
属微粒子表層部に金属化合物の被膜を形成する方法（特
開昭６３−１８４３０６）や強磁性金属微粒子表層部に
マグネタイト被膜を形成する方法（特公昭６３−５４０
４１）等が提案されている。Normally, the reduction reaction is carried out using hydrogen or a reducing gas mainly composed of hydrogen, but by entraining water vapor to the reducing gas in the early stage of the reduction, the specific surface area of iron or iron-based metal obtained by thermal reduction is reduced. Method of lowering (Tokuko Sho 6l-
36048) has been proposed. In addition, since iron or iron-based metals obtained by thermal reduction will oxidize and burn in the atmosphere, it is possible to safely handle them in the atmosphere, and the oxidation of ferromagnetic metals will progress. Techniques to prevent deterioration of magnetic properties over time are important. Conventionally, a method of forming an oxide film on the surface layer of ferromagnetic metal particles by gas phase contact reaction or liquid phase reaction has been known as a means to ensure oxidation stability. A method of heat-treating at a high temperature after formation (Japanese Patent Application Laid-Open No. 61-154112), a method of forming a film of a metal compound on the surface layer of ferromagnetic metal fine particles (Japanese Patent Laid-Open No. 63-184306), Method of forming a film (Special Publication No. 63-540
41) etc. have been proposed.
〔発明が解決しようとする課Ｂ］
上記の如く、鉄又は鉄を主体とした強磁性金属微粒子を
良好な特性の磁気記録用素材とするには極めて複雑な工
程を必要とする。これらに於いて表面変性したオキシ水
酸化鉄をそのまま還元すると多孔質な金属粉末となり、
あるいは針状形状がこわれてしまうので還元に先だって
５００〜８００℃において仮焼し細孔の少ない酸化鉄（
α−Ｆｅｚｅ３、ｐｅｓｏ４）にしてから還元すること
が行われている。[Problem B to be Solved by the Invention] As described above, an extremely complicated process is required to make iron or ferromagnetic metal fine particles mainly composed of iron into a magnetic recording material with good characteristics. In these cases, if the surface-modified iron oxyhydroxide is directly reduced, it becomes a porous metal powder.
Alternatively, since the needle-like shape will be broken, iron oxide with fewer pores is calcined at 500 to 800°C prior to reduction.
α-Feze3, peso4) and then reduction is performed.
また細孔の少ない酸化鉄を表面変性してから還元するこ
とが行われている。Also, iron oxide with few pores is surface-modified and then reduced.
しかし、これらの方法では還元における酸化鉄からα−
Ｆｅへの反応過程で発生する細孔は防止することが出来
ない。However, in these methods, α-
Pores generated during the reaction process to Fe cannot be prevented.
本発明者等は、上記問題について鋭意研究を行った結果
、飽和磁化が大きく優れた磁気特性を有し、酸化安定性
にも優れた本発明に到達した。即ち本発明の強磁性金属
粉末の製造方法は、鉄もしくは鉄化合物を主体とする金
属化合物を還元性雰囲気中で加熱還元して強磁性金属粉
末を製造するに際し、最初の還元反応終了後酸化処理を
行って該強磁性金属粉末の表面に酸化被膜をつくり、し
かる後に再び加熱還元処理を行って更に酸化処理をも行
い、この樺な加熱還元、酸化処理を二度以上繰り返すこ
とを特徴とするものである。As a result of intensive research into the above-mentioned problems, the present inventors have arrived at the present invention, which has excellent magnetic properties with large saturation magnetization and excellent oxidation stability. That is, in the method for producing ferromagnetic metal powder of the present invention, when producing ferromagnetic metal powder by heating and reducing iron or a metal compound mainly consisting of an iron compound in a reducing atmosphere, an oxidation treatment is performed after the completion of the first reduction reaction. The method is characterized in that an oxide film is formed on the surface of the ferromagnetic metal powder, and then a heat reduction treatment is performed again, and further an oxidation treatment is performed, and this heat reduction and oxidation treatment are repeated two or more times. It is something.
本発明の特徴とするところは、鉄もしくは鉄を主体とす
る化合物例えばオキシ水酸化物或いは酸化物を形状保持
、粒子間焼結の防止などの目的で珪素・アルミニウム化
合物などによる表面処理を行ったのち、これを水素もし
くは水素を主体とした還元性雰囲気中で加熱還元を行い
、更に酸化性ガスによる気相接触反応あるいは液相反応
により強磁性金属微粒子表層部に酸化被膜を形成させ安
定化する一連の酸化、還元操作を２度以上行う事にある
。A feature of the present invention is that iron or iron-based compounds such as oxyhydroxides or oxides are surface-treated with silicon/aluminum compounds for the purpose of retaining their shape and preventing interparticle sintering. This is then thermally reduced in hydrogen or a reducing atmosphere mainly composed of hydrogen, and further stabilized by forming an oxide film on the surface layer of the ferromagnetic metal particles through a gas phase contact reaction or liquid phase reaction using an oxidizing gas. It involves performing a series of oxidation and reduction operations two or more times.
通常、出発原料であるオキシ水酸化鉄あるいは酸化鉄は
形状保持、粒子間焼結の防止の為に種々の金属化合物を
共沈あるいは被着させているので適正な磁気特性を得る
還元温度は耐熱成分の種類や量により異なり保磁力、飽
和磁化、比表面積のバランスのとれる還元温度が選ばれ
る。従って、適正還元温度以上における還元は、強磁性
金属微粒子の粒子内あるいは粒子間の焼結が進み過ぎて
磁気特性、特に保磁力の低下を招くので好ましくない。Normally, the starting material iron oxyhydroxide or iron oxide is co-precipitated or coated with various metal compounds in order to maintain its shape and prevent interparticle sintering, so the reduction temperature required to obtain appropriate magnetic properties is heat resistant. Depending on the type and amount of the components, a reduction temperature that provides a balance between coercive force, saturation magnetization, and specific surface area is selected. Therefore, reduction at a temperature higher than the appropriate reduction temperature is not preferable because sintering within or between the ferromagnetic metal fine particles progresses too much, leading to a decrease in magnetic properties, particularly coercive force.
本発明は該強磁性金属微粒子を酸化性ガスによる気相接
触反応あるいは液相反応により強磁性金属微粒子表層部
に酸化被膜を形成させた後に、更に再び水素もしくは水
素を主体とした還元性雰囲気中で加熱還元を行う事を特
徴としている。In the present invention, after forming an oxide film on the surface layer of the ferromagnetic metal fine particles by a vapor phase contact reaction or liquid phase reaction with an oxidizing gas, the ferromagnetic metal fine particles are further placed in hydrogen or a reducing atmosphere mainly composed of hydrogen. It is characterized by thermal reduction.
もちろん、得られた強磁性金属微粒子はそのまま空気中
に暴露すれば、酸化燃焼してしまうので酸化性ガスによ
る気相接触反応あるいは液相反応により強磁性金属微粒
子表層部に酸化被膜を形成させる安定化処理しなければ
ならない。すなわち、本発明は還元−酸化一還元一酸化
を２度以上くり返す事を特徴とする。１度目の酸化処理
は例えば１度目の還元反応終了後同一反応器において還
元性ガスを不活性ガスに切替えてから酸化性ガスである
酸素あるいは水を同伴させる事により酸化処理を行う程
度で良く、あるいは１度目の還元反応終了後同一反応器
において温度２５０〜５００℃において還元性ガスと水
蒸気の混合ガスを流通し強磁性金属微粒子もしくはその
表層部をマグネタイトにした後、２度目の還元反応を行
えばよい、１度目の酸化処理の程度は出発原料である酸
化鉄あるいはオキシ酸化鉄の比表面積、サイズ、軸比等
により、又出発原料の表面処理成分の種類、量により異
なるので特定できないが通常の還元反応を経た強磁性金
属微粒子の飽和磁化よりも２０ｅｍｕ／ｇ以上低くすれ
ば、その効果を充分に発現する事ができる。かならずし
も大気中に出しても発火しなくなるまで酸化処理をする
必要はない。本発明の効果は還元−酸化を２度以上（り
返す事により細孔の少ない焼き締まった強磁性金属微粒
子を製造する事ができる事である。 再度の還元後得ら
れた強磁性金属微粒子を例えばトルエン等の有機溶剤に
浸漬し空気等の酸化性ガスを通気する湿式の酸化安定処
理、あるいは例えば窒素ガス等の不活性ガスを通気し、
徐々に酸素ガス等の酸化性ガスの流量を増加していく乾
式の酸化安定化処理により優れた特性の強磁性金属微粒
子を製造する事ができる。Of course, if the obtained ferromagnetic metal fine particles are exposed to the air as they are, they will oxidize and burn, so a stable oxide film is formed on the surface of the ferromagnetic metal fine particles through a gas phase contact reaction or liquid phase reaction with an oxidizing gas. It must be processed by chemical treatment. That is, the present invention is characterized in that reduction, oxidation, monoreduction, and monoxidation are repeated two or more times. For example, the first oxidation treatment may be performed by switching the reducing gas to an inert gas in the same reactor after the first reduction reaction is completed, and then carrying out the oxidation treatment by entraining the oxidizing gas, such as oxygen or water. Alternatively, after the first reduction reaction is completed, a mixed gas of reducing gas and water vapor is passed through the same reactor at a temperature of 250 to 500°C to turn the ferromagnetic metal fine particles or their surface layer into magnetite, and then the second reduction reaction is performed. The degree of the first oxidation treatment cannot be determined because it varies depending on the specific surface area, size, axial ratio, etc. of the starting material iron oxide or iron oxyoxide, as well as the type and amount of the surface treatment component of the starting material, but it is normal. If the saturation magnetization of the ferromagnetic metal fine particles subjected to the reduction reaction is lowered by 20 emu/g or more, the effect can be fully exhibited. There is no need to oxidize the material until it no longer ignites even if exposed to the atmosphere. The effect of the present invention is that by repeating reduction and oxidation two or more times, it is possible to produce hardened ferromagnetic metal fine particles with few pores. For example, wet oxidation stabilization treatment is performed by dipping in an organic solvent such as toluene and aerating an oxidizing gas such as air, or by aerating an inert gas such as nitrogen gas.
Ferromagnetic metal fine particles with excellent characteristics can be produced by dry oxidation stabilization treatment in which the flow rate of oxidizing gas such as oxygen gas is gradually increased.
本発明の方法は還元−酸化を２度以上くり返す事が特徴
であり、強磁性金属微粒子の粒子内の焼結を促進する事
が目的である。その作用は比表面積測定やＸ線回折によ
る結晶部分である鉄を主体とした金属の結晶子（グレイ
ン）のサイズの測定等で確かめる事ができる。すなわち
、本発明の方法を実施する事により強磁性金属微粒子の
比表面積は低下し、Ｘ線回折により求められた金属の結
晶子サイズは大きくなる事により、結晶子の成長及び粒
子内の結晶子間のネッキングの成長により粒子内の焼結
が促進し、その結果として飽和磁化が高く、叉酸化安定
性が増大すると思われる。The method of the present invention is characterized by repeating reduction and oxidation twice or more, and its purpose is to promote sintering within the ferromagnetic metal fine particles. This effect can be confirmed by measuring the specific surface area or measuring the size of crystallites (grains) of metals mainly made of iron, which are crystalline parts, using X-ray diffraction. In other words, by carrying out the method of the present invention, the specific surface area of the ferromagnetic metal fine particles decreases, and the metal crystallite size determined by X-ray diffraction increases, thereby reducing the growth of crystallites and the crystallites within the particles. It is believed that the growth of necking between particles promotes sintering within the grains, resulting in higher saturation magnetization and increased cross-oxidation stability.
以下、実施例及び比較例により本発明の方法及びその効
果を詳細に説明する。Hereinafter, the method of the present invention and its effects will be explained in detail using Examples and Comparative Examples.
実施例１
耐熱成分として珪素を含有するα−オキシ水酸化鉄（Ｓ
ｉ／Ｆｅ＝３．５／１００ｗｔりを水素ガスを流通しな
がら４００℃で、８時間遅元した。冷却後、不活性ガス
雰囲気で注意深くセルに詰め試料振動型磁力針（ＶＳＭ
−１１１束英工業社製）で得られた強磁性金属鉄微粒子
の磁気特性を測定したところ、保磁力（ＩＣ）１４８２
０ｅ 、飽和磁化（ｔｒ ｓ） １７９ｅ＋ｗｕ／ｇ、
角形比（Ｒ）０．５１であった。得られた強磁性金属鉄
微粒子を窒素ガスを流通しながら空気を入れ（窒素／空
気＝９／１）、徐々に空気量を増加させて１０時間後に
空気だけを流通し酸化安定化処理を行った。Example 1 α-Iron oxyhydroxide (S) containing silicon as a heat-resistant component
i/Fe=3.5/100wt was heated at 400° C. for 8 hours while flowing hydrogen gas. After cooling, the sample is carefully packed into a cell in an inert gas atmosphere and placed in a vibrating magnetic needle (VSM).
-111 (manufactured by Fukuei Kogyo Co., Ltd.), the magnetic properties of the ferromagnetic metal iron fine particles obtained were measured, and the coercive force (IC) was 1482.
0e, saturation magnetization (tr s) 179e+wu/g,
The squareness ratio (R) was 0.51. The obtained ferromagnetic metal iron fine particles were introduced with air while flowing nitrogen gas (nitrogen/air = 9/1), the amount of air was gradually increased, and after 10 hours, only air was passed through to perform oxidation stabilization treatment. Ta.
得られた強磁性金属鉄微粒子の磁気特性は保磁力（Ｈｅ
）１５６５０ｅ 、飽和磁化（ａ ｓ） １３０ｅｍｕ
／ｇ、角形比（ＩＩ）０．５２であり比表面積は５６．
１ｒｒｒ／ｇであった。The magnetic properties of the obtained ferromagnetic metallic iron fine particles are determined by coercive force (He
) 15650e, saturation magnetization (as) 130emu
/g, the squareness ratio (II) is 0.52, and the specific surface area is 56.
It was 1rrr/g.
更に、得られた強磁性金属鉄微粒子を水素ガスを流通し
ながら４００℃で、４時間遅元した。冷却後得られた強
磁性金属鉄微粒子の磁気特性を測定した所、保磁力（Ｈ
ｅ）１５０６０ｅ 、飽和磁化（ｔｒ ｓ） １８２ｅ
ｌｌｕ／ｇ、角形比（Ｒ）０．５１であった。得られた
強磁性金属鉄微粒子を窒素ガスを流通しながら空気を入
れ（窒素／空気＝９／１）、徐々に空気量を増加させて
１０時間後に空気だけを流通し酸化安定化処理を行った
。得られた強磁性金属鉄微粒子の磁気特性は保磁力（Ｈ
ｅ）１５８１０ｅ 、飽和磁化（ｔｙ ｓ） １３５ｅ
＋＊ｕ／ｇ、角形比（Ｒ）０．５３であり、比表面積は
５０．３ボ／ｇであった。該強磁性金属鉄微粒子を透過
型電子顕微鏡で観察すると、イメージ上は破損、破壊は
見られず、粒子も１本１本の形状を保持した細孔のほと
んどないイメージである事がわかった。すなわち、還元
−酸化を２度くり返す事により比表面積が大きく低下し
、その結果として飽和磁化を高くする事ができた。Further, the obtained ferromagnetic metal iron fine particles were heated at 400° C. for 4 hours while flowing hydrogen gas. When the magnetic properties of the ferromagnetic metallic iron fine particles obtained after cooling were measured, the coercive force (H
e) 15060e, saturation magnetization (tr s) 182e
llu/g, and the squareness ratio (R) was 0.51. The obtained ferromagnetic metal iron fine particles were introduced with air while flowing nitrogen gas (nitrogen/air = 9/1), the amount of air was gradually increased, and after 10 hours, only air was passed through to perform oxidation stabilization treatment. Ta. The magnetic properties of the obtained ferromagnetic metal iron fine particles are determined by the coercive force (H
e) 15810e, saturation magnetization (ty s) 135e
+*u/g, the squareness ratio (R) was 0.53, and the specific surface area was 50.3 bo/g. When the ferromagnetic metal iron fine particles were observed with a transmission electron microscope, no damage or destruction was observed in the image, and the image showed that each particle retained its individual shape and had almost no pores. That is, by repeating reduction and oxidation twice, the specific surface area was greatly reduced, and as a result, the saturation magnetization was able to be increased.
実施例２
耐熱成分としてアルミニウムを含有するα−オキシ水酸
化鉄（Ａ Ｉ／Ｆｅ＝５．２／ １００ｗ Ｈ）を、窒
素ガスを流通しながら５００°Ｃで２時間仮焼し、３５
０°Ｃで水素ガスを流通しながら８時間還元し、更に窒
素ガスを流通しながら３００℃に温度を下げ、酸素を０
．０１ ｖｏ１％含有する窒素ガスを１時間流通した。Example 2 α-Iron oxyhydroxide (AI/Fe=5.2/100wH) containing aluminum as a heat-resistant component was calcined at 500°C for 2 hours while flowing nitrogen gas,
Reduction was carried out at 0°C for 8 hours while passing hydrogen gas, and then the temperature was lowered to 300°C while passing nitrogen gas, and the oxygen was reduced to 0.
．． Nitrogen gas containing 1% of 01 vol was passed for 1 hour.
冷却後、得られた強磁性金属鉄微粒子の磁気特性を測定
したところ、保磁力（Ｈｅ）１３７１０ｅ 、飽和磁化
（ａ ｓ） １４６ｅｓｕ／ｇ、角形比（１？）０．４
９であった。更に得られた強磁性金属鉄微粒子を水素ガ
スを流通しながら４００℃で４時間還元した。After cooling, the magnetic properties of the obtained ferromagnetic metallic iron particles were measured and found that the coercive force (He) was 13710e, the saturation magnetization (as) was 146 esu/g, and the squareness ratio (1?) was 0.4.
It was 9. Furthermore, the obtained ferromagnetic metal iron fine particles were reduced at 400° C. for 4 hours while flowing hydrogen gas.
冷却後得られた強磁性金属鉄微粒子の磁気特性を測定し
たところ、保磁力（）ｌｃＨ４７３０ｅ 、飽和磁化（
ａ ｓ） １８２ｅｍｕ／ｇ、角形比（Ｒ）であった。When the magnetic properties of the ferromagnetic metallic iron fine particles obtained after cooling were measured, the coercive force () lcH4730e and the saturation magnetization (
a s) 182 emu/g, squareness ratio (R).
得られた強磁性金属鉄微粒子を窒素ガスを流通しながら
空気を入れ（窒素／空気＝９９ ／１）、徐々に空気量
を増加させて１０時間後に空気だけを流通し酸化安定化
処理を行った。得られた強磁性金属鉄微粒子の磁気特性
は保磁力（Ｈｅ）１５０７０ｅ 、飽和磁化（ｙｓ）１
４５ｅｍｕ／ｇ 、角形比（Ｒ）０．５１であり、比
表面積は４４．９ポ／ｇであった。The obtained ferromagnetic metallic iron fine particles were introduced with air while flowing nitrogen gas (nitrogen/air = 99/1), the amount of air was gradually increased, and after 10 hours, only air was passed through to perform oxidation stabilization treatment. Ta. The magnetic properties of the obtained ferromagnetic metallic iron particles are coercive force (He) of 15070e and saturation magnetization (ys) of 1.
45 emu/g, the squareness ratio (R) was 0.51, and the specific surface area was 44.9 po/g.
該強磁性金属鉄微粒子を透過型電子顕微鏡で観察すると
、イメージ上は破損、破壊は見られず、粒子も１本１本
の形状を保持したボアのほとんどないイメージである事
がわかった。すなわち、還元−酸化を２度くり返す事に
より比表面積が大きく低下し、その結果として飽和磁化
を高くする事ができた。When the ferromagnetic metal iron fine particles were observed with a transmission electron microscope, it was found that no damage or destruction was observed in the image, and the image showed that each particle retained its individual shape and had almost no bores. That is, by repeating reduction and oxidation twice, the specific surface area was greatly reduced, and as a result, the saturation magnetization was able to be increased.
比較例１
実施例２と同様のアルえニウム含有α−オキシ水酸化鉄
（ＡＩ／Ｆｅ＝５．２／１００ｗｔχ）を窒素ガスを流
通しながら５００℃で、２時間仮焼し、３５０ ”Ｃで
水素ガスを流通しながら、８時間還元を行った。冷却後
、得られた強磁性金属鉄微粒子の磁気特性を測定した所
、保磁力（Ｈｅ）１４３２０ｅ 、飽和磁化（ａｓ）
１８０ｅｍｕ／ｇ、角形比（Ｒ）０．４９であった。還
元反応で得られた強磁性金属鉄微粒子を窒素ガスを流通
しながら空気を入れ（窒素／空気＝９９ ／１）、徐々
に空気量を増加させて１０時間後に空気だけを流通し酸
化安定化処理を行った。得られた強磁性金属鉄微粒子の
磁気特性は保磁力（Ｈｃ）１５１９０ｅ 、飽和磁化（
ａ ｓ） １２６ｅｍｕ／ｇ、角形比（Ｒ）０．５１で
あり、比表面積は５５．３ボアｇであった。Comparative Example 1 Alenium-containing α-iron oxyhydroxide (AI/Fe=5.2/100wtχ) similar to Example 2 was calcined at 500°C for 2 hours while flowing nitrogen gas, and heated to 350"C. Reduction was carried out for 8 hours while flowing hydrogen gas.After cooling, the magnetic properties of the obtained ferromagnetic metallic iron particles were measured and found to be coercive force (He) of 14320e and saturation magnetization (as).
It was 180 emu/g and the squareness ratio (R) was 0.49. Ferromagnetic metallic iron fine particles obtained by reduction reaction are introduced with air while flowing nitrogen gas (nitrogen/air = 99/1), gradually increasing the amount of air, and after 10 hours, oxidation is stabilized by passing only air. processed. The magnetic properties of the obtained ferromagnetic metal iron fine particles include a coercive force (Hc) of 15190e and a saturation magnetization (
a s) 126 emu/g, the squareness ratio (R) was 0.51, and the specific surface area was 55.3 bore g.
比較例２
実施例２と同様のアルミニウム含有α−オキシ水酸化鉄
（Ａｔ／Ｆｅ＝５．２／１００ｗｔＸ）を窒素ガスを流
通しながら５００℃で、２時間仮焼し、４００℃で水素
ガスを流通しながら、８時間還元を行った。冷却後、得
られた強磁性金属鉄微粒子の磁気特性を測定した所、保
磁力（Ｈｃ）１３５１０ｅ 、飽和磁化Ｃａ５） １８
０ｅ＊ｕ／ｇ、角形比（１？）０．４８であった。還元
反応で得られた強磁性金属鉄微粒子を窒素ガスを流通し
ながら空気を入れ（窒素／空気・９９ ／１）、徐々に
空気量を増加させて１０時間後に空気だけを流通し酸化
安定化処理を行った。得られた強磁性金属鉄微粒子の磁
気特性は保磁力（Ｈｃ）１４３７０ｅ 、飽和磁化（ｒ
ｓ） １３６ｅｍｕ／ｇ 、角形比（［１）０．４９で
あり、比表面積は４９．４ボアｇであった。Comparative Example 2 The same aluminum-containing α-iron oxyhydroxide (At/Fe=5.2/100wt Reduction was carried out for 8 hours while circulating. After cooling, the magnetic properties of the obtained ferromagnetic metallic iron particles were measured and found that the coercive force (Hc) was 13510e and the saturation magnetization Ca5) 18
It was 0e*u/g and the squareness ratio (1?) was 0.48. Ferromagnetic metal iron fine particles obtained by reduction reaction are introduced with air while flowing nitrogen gas (nitrogen/air, 99/1), gradually increasing the amount of air, and after 10 hours, only air is passed through to stabilize the oxidation. processed. The magnetic properties of the obtained ferromagnetic metallic iron fine particles include a coercive force (Hc) of 14370e and a saturation magnetization (r
s) 136 emu/g, the squareness ratio ([1) was 0.49, and the specific surface area was 49.4 bore g.
該強磁性金属鉄微粒子を透過型電子顕微鏡で観察すると
、イメージ上は破損、破壊は見られなかったが、粒子１
本は溶けそうなイメージであり、粒子間焼結も激しい事
がわかった。When the ferromagnetic metal iron fine particles were observed with a transmission electron microscope, no damage or destruction was observed in the image, but particle 1
The book looked like it was going to melt, and it was clear that interparticle sintering was severe.
本発明の方法によれば、細孔の少ない飽和磁化値の大き
い、形状保持及び磁気特性に優れ、酸化安定性にも優れ
た鉄又は鉄を主体とする強磁性金属粉末を容易に製造す
る事が出来る。According to the method of the present invention, it is possible to easily produce iron or iron-based ferromagnetic metal powder that has few pores, a high saturation magnetization value, excellent shape retention and magnetic properties, and excellent oxidation stability. I can do it.
Claims (1)
雰囲気中で加熱還元して強磁性金属粉末を製造するに際
し、最初の還元反応終了後酸化処理を行って該強磁性金
属粉末の表面に酸化被膜をつくり、しかる後に再び加熱
還元処理を行って酸化処理をも行い、この様な加熱還元
、酸化処理を二度以上繰り返すことを特徴とする強磁性
金属粉末の製造方法。When producing ferromagnetic metal powder by thermally reducing iron or a metal compound mainly composed of iron compounds in a reducing atmosphere, oxidation treatment is performed after the initial reduction reaction to form an oxide film on the surface of the ferromagnetic metal powder. 1. A method for producing ferromagnetic metal powder, which is characterized by producing a ferromagnetic metal powder, followed by subjecting it to a heat reduction treatment and oxidation treatment again, and repeating such heat reduction and oxidation treatment twice or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2049325A JPH03253505A (en) | 1990-03-02 | 1990-03-02 | Production of ferromagnetic metal powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2049325A JPH03253505A (en) | 1990-03-02 | 1990-03-02 | Production of ferromagnetic metal powder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03253505A true JPH03253505A (en) | 1991-11-12 |
Family
ID=12827832
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2049325A Pending JPH03253505A (en) | 1990-03-02 | 1990-03-02 | Production of ferromagnetic metal powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03253505A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004056091A (en) * | 2002-05-31 | 2004-02-19 | Fuji Photo Film Co Ltd | Magnetic particle and its manufacturing method, and magnetic recording medium and its manufacturing method |
| JP2009256717A (en) * | 2008-04-15 | 2009-11-05 | Toda Kogyo Corp | Manufacturing method of magnetic recording metal magnetic grain powder, and magnetic recording medium |
| JP2010225268A (en) * | 2010-05-06 | 2010-10-07 | Dowa Holdings Co Ltd | Magnetic powder for magnetic recording medium, manufacturing method therefor, and magnetic recording medium using the powder |
-
1990
- 1990-03-02 JP JP2049325A patent/JPH03253505A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004056091A (en) * | 2002-05-31 | 2004-02-19 | Fuji Photo Film Co Ltd | Magnetic particle and its manufacturing method, and magnetic recording medium and its manufacturing method |
| JP4524078B2 (en) * | 2002-05-31 | 2010-08-11 | 富士フイルム株式会社 | Magnetic particle and method for manufacturing the same, and magnetic recording medium and method for manufacturing the same |
| JP2009256717A (en) * | 2008-04-15 | 2009-11-05 | Toda Kogyo Corp | Manufacturing method of magnetic recording metal magnetic grain powder, and magnetic recording medium |
| JP2010225268A (en) * | 2010-05-06 | 2010-10-07 | Dowa Holdings Co Ltd | Magnetic powder for magnetic recording medium, manufacturing method therefor, and magnetic recording medium using the powder |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5623301B2 (en) | Magnetic particle, method for producing the same, and magnetic recording medium | |
| EP0717397A2 (en) | Spindle-shaped magnetic ironbased alloy particles containing cobalt and iron as the main ingredients and process for producing the same | |
| US4318735A (en) | Process for preparing magnetic particles with metallic region therein, and magnetic particles prepared by the process | |
| JPH09295814A (en) | Spindle-like geothite particle powder, its production, spindle-like metal magnetic particle powder consisting mainly of iron and obtained by using the same geothite particle powder as starting raw material and its production | |
| JPS61154112A (en) | Stabilization method of ferromagnetic metallic particulate | |
| JPH03253505A (en) | Production of ferromagnetic metal powder | |
| JP5711086B2 (en) | Magnetic powder for magnetic recording, method for producing the same, and magnetic recording medium | |
| JPS61196502A (en) | Magnetic material and manufacture thereof | |
| JPH0123402B2 (en) | ||
| JPH08109401A (en) | Metallic powder for magnetic recording and its production | |
| JPS61234506A (en) | Magnetic material and manufacture thereof | |
| JP4182310B2 (en) | Method for producing spindle-shaped alloy magnetic particle powder mainly composed of Fe and Co for magnetic recording | |
| KR19990077521A (en) | Spindle-shaped goethite particles and process for producing the same | |
| JPH0143683B2 (en) | ||
| EP0433894B1 (en) | Process for producing magnetic metal powder for magnetic recording | |
| JPS5919964B2 (en) | Method for producing ferromagnetic metal powder | |
| JP5447767B2 (en) | Method for producing ferromagnetic metal particle powder | |
| JP4929473B2 (en) | Magnetic powder for magnetic recording medium, method for producing the same, and magnetic recording medium using the same | |
| JP3171223B2 (en) | Method for producing acicular magnetic particle powder | |
| JP3242102B2 (en) | Magnetic powder and method for producing the same | |
| JPH02197501A (en) | Production of ferromagnetic metal powder | |
| JPS61216306A (en) | Magnetic metal powder and manufacture thereof | |
| JPH03257104A (en) | Manufacture of ferromagnetic metal powder | |
| JPH05140620A (en) | Production of powdery ferromagnetic metal powder | |
| JP5700191B2 (en) | Method for producing ferromagnetic metal particle powder, magnetic recording medium |