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公开(公告)号：JPH04260303A
公开(公告)日：1992-09-16
申请号：JP2184591
申请日：1991-02-15
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAGAWA KIMITERU , UMEHARA HIDEKI , UTSUNO NORITOSHI
IPC: H01F1/06
Abstract: PURPOSE:To obtain ferromagnetic metal powder for magnetic recording use which has high saturation magnetization and oxidation stability. CONSTITUTION:In addition to Si, Al, etc., which have been conventionally used as preventing components of sintering, transition metal elements like Cr, Mn, etc., are precipitated by using alkali carbonate, and stuck on the surface of oxy hydroxide or oxide whose main component is iron. By this method, a lot of metal elements can be uniformly precipitated and stuck. In a process wherein ferromagnetic metal powder is formed by using the above material, the purpose can be attained by the effect of interaction (formation of alloy, ferrite, etc., on the surface) between iron as the main component and the metal elements which are precipitated and stuck.
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公开(公告)号：JPH02204333A
公开(公告)日：1990-08-14
申请号：JP1984689
申请日：1989-01-31
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAGAWA KIMITERU , HAYASHI FUJIO , UTSUNO NORITOSHI
Abstract: PURPOSE:To improve dispersibility in a resin binder by hydrolyzing a soln. of alcohol-soluble ferric salts in alcohol and heating the resulting sol. CONSTITUTION:Alcohol-soluble ferric salts (e.g. FeCl2) are dissolved in alcohol (e.g. methanol) and alcohol-soluble salts of one or more among Ba, Sr, Pb, Co, Ni and Ti (e.g. BaCl2) are further dissolved as required. Water is added to the resulting soln. and this soln. is hydrolyzed to obtain a sol. This sol and alcohol are heated at 150-600 deg.C for 0.5-20hr to obtain fine iron-based oxide particles in the form of hexagonal platy magnetic oxide particles contg. at least one among Ba, Br, Pb, Co, Ni and Ti and having magnetoplumbite structure.
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公开(公告)号：JPS636806A
公开(公告)日：1988-01-12
申请号：JP14944986
申请日：1986-06-27
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TSUMURA RYUICHIRO , OSHIMA KAZUFUMI , MURAISHI TERUO , UTSUNO NORITOSHI
Abstract: PURPOSE:To improve the corrosion resistance of hexagonal crystal cobalt magnetic powder without decreasing a saturated magnetization by reducing cobalt hydroxide directly using liquid phase hydrogen in medium of inert organic compound to form magnetic powder made of hexagonal crystal cobalt platelike fine particles. CONSTITUTION:2.32 g of cobalt hydroxide pink fine powder (hexagonal crystal cobalt hexagonal platelike fine particles having particle size is 0.01-1mum preferably dispersed without coagulation), 0.02 g of polyethyleneglycollauryl ether as a surfactant, 100 ml of heptane as an inert reactive medium are prepared in a nitrogen atmosphere in a 200 ml stainless steel autoclave. After hydrogen is press-fitted at 30 kg/cm , the mixture is reacted at 220 deg.C for 1 hour while vigorously stirring it. Then, the mixture is cooled and allowed to stand for, the content is then removed, the heptane is inclined and separated. Thus, corrosion resistant and stable powder having suitable retaining strength is obtained without reducing saturated magnetization, exhibiting uniaxial crystal magnetic anisotropy with good crystallinity used for vertical magnetic recording magnetic powder.
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公开(公告)号：JPH03293703A
公开(公告)日：1991-12-25
申请号：JP19905790
申请日：1990-07-30
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAGAWA MIKITERU , TAKAHASHI SEIICHI , UTSUNO NORITOSHI , UMEHARA HIDEKI , HAYASHI FUJIO , KOBA SHIGEO , SUDA SATORU
Abstract: PURPOSE:To make them into fine particles without sacrifice of high saturation magnetization so as to improve the stability to oxidation by providing a ferrite film, which has the spinel structure consisting of a specific metallic element, cobalt, and iron, in the surface layer part. CONSTITUTION:The particle surface layer part is covered with the film of a ferrite compound, which has the spinel structure consisting of cobalt, iron, and another metal, which is selected from zinc, manganese, aluminum, chromium, and copper. That is, oxyhydroxide mainly composed of iron, which has the ferrite film having superfine spinel structure on the surface, is excellent in shape preserving effect by the property of this film. Furthermore, for the film oxide formed after gentle surface oxidation, the ferrite structure having spinel structure is succeeded, and a fine film oxide excellent in oxidation stability can be obtained. Hereby, the stability to oxidation can be obtained with high holding power and high saturation magnetization maintained.
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公开(公告)号：JPS62156209A
公开(公告)日：1987-07-11
申请号：JP29287385
申请日：1985-12-27
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAGAWA KIMITERU , UTSUNO NORITOSHI , SUDOU KAZUFUYU
Abstract: PURPOSE:To produce ferromagnetic metallic powder having excellent magnetic characteristics and weatherability by subjecting iron oxyhydroxide to a deposition treatment with a Zr compd. then depositing a specific compd. thereon in the stage of subjecting the iron oxyhydroxide, etc. to hydrogen reduction to produce the ferromagnetic metallic particles. CONSTITUTION:The iron oxyhydroxide or iron oxide is suspended in water to form the slurry or paste thereof, to which zirconium nitrate and zirconium oxychloride are added to make 0.1/100-5/100 ratio of the weight between Zr/Fe to deposit the same onto the particle surface of the iron oxyhydroxide, etc. A water soluble compd. of at least one kind of Si, Al, P, and B is then deposited thereon at 0.1/100-5/100 ratio to the weight of Fe. Such iron hydroxide is filtered, dried and ground, then said iron is calcined in air at >=600 deg.C and in succession thereof, the iron hydroxide is subjected to reduction by gaseous hydrogen. The ferromagnetic metallic powder having the excellent magnetic characteristics and weatherability is thus produced.
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Patent Agency Ranking
公开(公告)号：JPH03174704A
公开(公告)日：1991-07-29
申请号：JP19777990
申请日：1990-07-27
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAGAWA KIMITERU , TAKAHASHI SEIICHI , UTSUNO NORITOSHI , UMEHARA HIDEKI , HAYASHI FUJIO , KOBA SHIGEO , SUDA SATORU
Abstract: PURPOSE:To improve oxidation stability and to maintain high saturated magnetization against deterioration of an environment by simultaneously neutralizing cobalt and iron in slurry in which iron-base oxyhydroxide particles are dispersed, and immediately forming gel generated directly as spinel compound as particle surface film. CONSTITUTION:The bivalent ions of cobalt and the trivalent ferric ions are simultaneously neutralized in slurry in which iron-base oxyhydroxide particles are dispersed, and gel generated directly as spinel compound is formed as film on the surfaces of the particles. Further, after ferromagnetic metal particles are formed to be obtained by heating, reducing, they are smoothly oxidized to stop the igniting property to form ferrite film having spinel structure on the surfaces of the particles. Thus, excellent oxidation stability is obtained, and even if an environment is deteriorated, highly saturated magnetization can be maintained.
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公开(公告)号：JPS636807A
公开(公告)日：1988-01-12
申请号：JP14945086
申请日：1986-06-27
Applicant: MITSUI TOATSU CHEMICALS
Inventor： SUDOU KAZUFUYU , HAYASHI FUJIO , UTSUNO NORITOSHI , TAGAWA KIMITERU
Abstract: PURPOSE:To easily prepare high dispersive magnetic paint by drying oxyhydroxide iron or iron oxide, or surfacemodified oxyhydroxide iron or iron oxide in the state flocculated in liquid. CONSTITUTION:Oxyhydroxide iron or iron oxide, or surfacemodified oxyhydroxide iron or iron oxide is suspended in liquid. Then, hydrogen ion concentration of suspension is so controlled as to become suspended flocculation range to be flocculated, and then dried. Then, it is converted to ferromagnetic iron fine particles by vapor contact reducting reaction with reducing gas. Thus, the secondary coagulation lump strength of the magnetic fine particles in ferromagnetic metal fine particles are much weakened. Accordingly, the fluidity of organic solvent slurry is very improved to extremely accelerate paint dispersion.
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公开(公告)号：JPH03293702A
公开(公告)日：1991-12-25
申请号：JP19778090
申请日：1990-07-27
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAGAWA MIKITERU , TAKAHASHI SEIICHI , UTSUNO NORITOSHI , UMEHARA HIDEKI , HAYASHI FUJIO , KOBA SHIGEO , SUDA SATORU
Abstract: PURPOSE:To make them into fine particles without sacrifice of high saturation magnetization so as to improve the stability to oxidation by providing a ferrite film, which has spinel structure consisting of specific metallic elements and iron, in the surface layer part. CONSTITUTION:The particle surface layer part is covered with the film of a ferrite compound, which has the spinel structure consisting of iron and another metal selected from zinc, nickel, manganese, aluminum, chromium, and copper. That is, the oxyhydroxide particle mainly composed of iron, which has the ferrite film having the superfine spinel structure on the surface, is excellent in shape preserving effect by the property of this film, and for the film oxide formed after gentle surface oxidation, the ferrite film structure having spinel structure is succeeded, and a fine film oxide excellent in oxidation stability can be obtained. Hereby, the stability to oxidation can be obtained with high holding power and high saturation magnetization maintained.
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公开(公告)号：JPS62156208A
公开(公告)日：1987-07-11
申请号：JP29287285
申请日：1985-12-27
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAGAWA KIMITERU , SUDOU KAZUFUYU , UTSUNO NORITOSHI
Abstract: PURPOSE:To produce ferromagnetic metallic powder which has a film contg. ZrO2 and excellent weatherability by treating iron oxyhydroxide with a Zr compd. in the stage of using the iron oxyhydroxide, etc., as a starting raw material and subjecting the material to hydrogen reduction to produce the ferromagnetic metallic particles essentially consisting of Fe. CONSTITUTION:The iron oxyhydroxide or oxide contg. at least one kind of P, Si, Al, and B at 0.1/100-5/100 ratio to the weight of Fe is suspended in water and the slurry or pasty Zr compd. such as zirconium nitrate is added thereto to make 0.1/100-5/100 ratio of the weight between Zr/F so that Zr ions are adsorbed on the particles of the iron hydroxide. Such iron hydroxide is subjected to filtering, washing, and drying and further to a heating treatment to >=600 deg.C in the atm. and in succession thereof, the iron hydroxide is subjected to the reduction treatment by hydrogen in a hydrogen atmosphere. The ferromagnetic metallic powder having excellent magnetic characteristics and weatherability is thus produced.
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公开(公告)号：JPS62156207A
公开(公告)日：1987-07-11
申请号：JP29287185
申请日：1985-12-27
Applicant: MITSUI TOATSU CHEMICALS
Inventor： TAGAWA KIMITERU , UTSUNO NORITOSHI , SUDOU KAZUFUYU
Abstract: PURPOSE:To produce pulverized ferromagnetic metallic powder suitable for high-density recording by co-depositing Zr and other hydroxides during the production of iron oxyhydroxide in the stage of subjecting the iron oxide obtd. from the iron oxyhydroxide to hydrogen reduction to produce the ferromagnetic metallic powder. CONSTITUTION:The raw material which is the iron oxyhydroxide such as ferrous sulfate or ferrous chloride is dissolved in water and at the same time a Zr compd. such as zirconium oxynitrate or zirconium oxychloride or further Si, P, Al, etc., are dissolved in the form of a sodium salt. Zr, Si, P and Al are incorporated therein at the content ratios thereof to Fe of 0.1/100-5/100 by weight of Zr/Fe, Si/Fe, P/Fe, and A/Fe. An alkaline agent is added to such soln., by which the hydroxide of Fe and the hydroxide of Zr or further Si, Al, and P are simultaneously co-deposited. After such soln. is dehydrated, the powder is calcined at >=600 deg.C in the atm. and is thereby reduced with hydrogen as a reducing agent, by which the pulverized ferromagnetic metallic particles as a magnetic stock for a magnetic recording medium is produced.
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