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CN1035088C - High-magnetocaloric-stability cobalt-modified gamma-ferric oxide magnetic powder and preparation method thereof - Google Patents

High-magnetocaloric-stability cobalt-modified gamma-ferric oxide magnetic powder and preparation method thereof Download PDF

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Publication number
CN1035088C
CN1035088C CN92105419A CN92105419A CN1035088C CN 1035088 C CN1035088 C CN 1035088C CN 92105419 A CN92105419 A CN 92105419A CN 92105419 A CN92105419 A CN 92105419A CN 1035088 C CN1035088 C CN 1035088C
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magnetic
magnetic powder
preparation
cobalt
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CN1071027A (en
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罗河烈
王桂华
钟夏平
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Institute of Physics of CAS
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Institute of Physics of CAS
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  • Compounds Of Iron (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)

Abstract

The invention relates to a method for preparing modified gamma-Fe doped with cobalt2O3Method for producing magnetic powders, in particular Mn-or P-doped cobalt-modified gamma-Fe with high magnetocaloric stability2O3The invention relates to magnetic powder and a preparation method thereof, in particular to cobalt modified gamma-Fe2O3Mn or P is coated on the surface of the magnetic powder, and after heat treatment, the ions are diffused into the crystal lattices of the magnetic powder, and when the magnetic powder is subjected to the action of a magnetic field and temperature, the activation energy of Co ion migration is greatly improved, so that the magnetocaloric stability of the coercive force of the magnetic powder is improved. The COxRv, Fe prepared by the method3-x-yO4R ═ Mn or P) magnetic powder is suitable for use in the manufacture of video tapes, digital recording tapes, magnetic disks, and the like.

Description

High-magnetic heat stability cobalt improved γ-di-iron trioxide magnetic and preparation method thereof
The present invention relates to a kind of preparation cobalt improved γ-Fe that mixes 2O 3The method of magnetic, particularly preparation are mixed the cobalt improved γ-Fe of the high-magnetic heat stability of phosphorus 2O 3The magnetic method.
Wrap the γ-Fe of attached Conjugate ferrite 2O 3Magnetic is the magnetic that is widely used in video recording and aspects such as digital record tape and disk at present.But there is the imperfect shortcoming of coercitive magnetic heat stability in it: the tape made from it has the signal of former record to be difficult for wiping under magnetic field and temperature act on simultaneously, shortcoming such as print-through is big.People such as Eiling mention in magnetic collects publication [A.Eilingand R.A.Rott, IEEE T.Magn.MAG-21 (5) (1985) 1497] article, have invented a kind of cobalt improved γ-Fe of high-magnetic heat stability 2O 3Magnetic, after 100 hours, its coercive force only drops to about 1% of original value, but does not provide the preparation technology of this magnetic at 40 ℃ and 3000 Oe the action of a magnetic fields for it.People such as Marcott narrate in the U.S.'s 4209412 patents, when preparation FeOOH, add CoSO simultaneously 4Solution and phosphatase reaction after reduction and oxidation, are made and are contained Co, γ-Fe of P 2O 3Magnetic.The coercive force of magnetic is improved.But whether they do not refer to the concrete preparation method and the coercitive magnetic heat stability of magnetic of this magnetic good.
The objective of the invention is to overcome the shortcoming and defect of above-mentioned prior art, in order to improve cobalt improved γ-Fe 2O 3The magnetic heat stability of magnetic, thus provide a kind of at cobalt improved γ-Fe 2O 3The magnetic surface makes the P ions diffusion with the attached P ion of chemical coprecipitation method bag in crystal through Overheating Treatment, forms Co xP yFe 3-x-yO 4Have high-magnetic heat stability magnetic and preparation method thereof
The object of the present invention is achieved like this:
With γ-Fe 2O 3Magnetic places in the reactor, adds the distilled water of 10 times of magnetic weight, is warming up to 90-100 ℃, and the blender about 100 rev/mins with rotating speed is sequentially added into FeSO while stirring 47H 2O, CoSO 47H 2O and (NaPO 3) 6 solution, after stirring in 10-60 minute, adding concentration while stirring is the NaoH solution of 200g/l.Afterwards, continue after stirring 50-150 minute between 90-100 ℃, sediment to be filtered, be washed till (neutrality) between the PH=6-8,, put into tube furnace then, at N 60-80 ℃ of oven dry down with distilled water 2Under the inert atmosphere, be heated to 390 ℃ of heat treatments 2 hours, be cooled to again between 200-250 ℃, oxidation 5-15 minute.After buried at above-mentioned heat place, cobalt and phosphorous diffusion were to γ-Fe 2O 3In the magnetic body, make and mix the cobalt improved ferrite Co of phosphorus xP yFe 3-x-yO 4The migration activation energy of the cobalt ions of magnetic is not more mixed the height of the magnetic of P, thereby the coercitive magnetic heat stability of magnetic is improved.The main chemical reactions formula of said process is as follows;
(1)
High-magnetic heat stability cobalt improved γ-Fe of the present invention 2O 3The composition formula of magnetic is as follows:
Co x P y Fe 3-x-yO 4
Wherein: x=y=0.01-0.2
Add each composition by γ-Fe 2O 3Percentage by weight is: the ((NaPO of 0-40Wt% 3); The CoSO of 5-40Wt% 4.7H 2O, the FeSO of 50-100Wt% 4.7H 2O.
Be elaborated below in conjunction with embodiment:
Embodiment 1
At room temperature with 10 gram needle-like γ-Fe 2O 3(long 0.5 μ m, mean axis be than 10: 1, coercivity H: 400 Oe) put into the reaction vessel of 0.5 liter, 200 milliliters of adding distil waters are warming up to 95 ℃ to magnetic, dispersed with stirring 1 hour.Under constantly stirring,, add the CoSO that concentration is 95 grams per liters successively every 10 minutes 47H 220 milliliters of O solution; 5 milliliters of the NaOH solution of 200 grams per liters, the FeSO of 125 grams per liters 47H 235 milliliters of the NaOH solution of 40 milliliters of O solution and 200 grams per liters.(the NaPO that when PH=8, adds 20 grams per liters 3) 620 milliliters of solution; After above-mentioned material adds, continue to stir 1 hour, be washed to PH=7; Filter, in oven dry below 60 ℃.
The magnetic that above-mentioned cladding is good is put into tube furnace, at N 2Under the atmosphere, 390 ℃ of heat treatment 2 hours, again 210 ℃ of oxidations about 10 minutes, this moment magnetic ferrous content at 1-3%.
The chemical composition analysis result of the magnetic that makes like this is: Co 2+=3.49wt%, Fe 2+=2.1wt%; P=0.88wt%
The basic magnetic of magnetic:
Coercive force HC=721 Oe specific saturation magnetization σ s=71.6emu/g
Magnetic is dispersed in the binder solution, is coated on the dacron chip base, in 2000 Oe are parallel to the magnetic field of sheet base, put driedly, make magnetic sheet.At this moment, the coercive force HC that is parallel to direction of orientation =803 Oe.
Smear sample is placed in the magnetic field of 3000 Oe, handled 12 hours at 90 ℃ perpendicular to sheet base direction in magnetic field.The coercive force H ' of the former direction of orientation of smear sample after magnetic heat treatment C ∥=788 Oe
Therefore, the ratio of the coercive force before and after the smear sample magnetic heat treatment: H ' / HC =98%; Promptly after magnetic heat treatment, the coercive force of sample has only descended 2% than before handling.
Embodiment 2
This is a reference example, is used for doing contrast with the performance of mixing the cobalt improved magnetic of P.
Press the cobalt improved γ-Fe of prepared of embodiment 1 2O 3Magnetic is except that not adding (NaPO 3) 6, outside the aqueous solution, all the other steps are all constant.The coercive force HC=729 Oe of the magnetic that makes like this; σ sThe coercive force H of=73.2emn/g smear sample C ∥=815 Oe.
Smear sample through with embodiment 1 the same terms magnetic heat treatment after, its coercive force H ' C ∥=717 Oe.
So do not mix cobalt improved γ-Fe of P 2O 3The ratio of the coercive force of magnetic magnetic heat treatment: H ' C ∥/ H C ∥=88%.The coercive force that is magnetic has descended 12% after magnetic heat treatment; Than mixing the cobalt improved γ-Fe of P 2O 3The coercitive magnetic heat stability of magnetic differs from about 10%.

Claims (3)

1, the high-magnetic heat stability cobalt improved γ-Fe of a kind of preparation 2O 3The method of magnetic comprises the following steps:
With γ-Fe 2O 3Magnetic is that raw material places in the reaction vessel, adds the distilled water of 10 times of magnetic weight, is warming up to 90-100 ℃, stirs with the blender limit of 100 rev/mins of rotating speeds, and the limit adds CoSO in order 47H 2O, FeSO 47H 2O and (NaPO 3) 6Solution adds each composition by γ-Fe 2O 3Percentage by weight is: (the NaPO of 10-40wt% 3) 6, the CoSO of 5-40Wt% 47H 2The FeSo of O and 50-100wt% 47H 2O stirred through 10-60 minute, and the NaOH solution that adds 200 grams per liters is stirred on the limit, afterwards, continuation is filtered sediment after stirring 50-150 minute between 90-100 ℃, is washed till (neutrality) between the PH=6-8 with distilled water, 60-80 ℃ of oven dry down, put into tube furnace, again at N 2Under the inert atmosphere, be heated to 390 ℃, heat treatment 2 hours is cooled between 200-250 ℃ again, oxidation 5-15 minute.
2, by the high-magnetic heat stability cobalt improved γ-Fe of the described preparation of claim 1 2O 3The method of magnetic is characterized in that described inert gas is N 2
3, a kind of by the direct high-magnetic heat stability magnetic of manufacturing of the described preparation method of claim 1 institute, it is characterized in that: it consists of Cox R yFe 3-x-yO 4
Wherein: x=y=0.01-0.2
CN92105419A 1992-07-10 1992-07-10 High-magnetocaloric-stability cobalt-modified gamma-ferric oxide magnetic powder and preparation method thereof Expired - Fee Related CN1035088C (en)

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CN92105419A CN1035088C (en) 1992-07-10 1992-07-10 High-magnetocaloric-stability cobalt-modified gamma-ferric oxide magnetic powder and preparation method thereof

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CN1035088C true CN1035088C (en) 1997-06-04

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* Cited by examiner, † Cited by third party
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CN101824237B (en) * 2010-05-05 2012-07-04 太原理工大学 Method for modifying and whitening kaolin

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5135697A (en) * 1974-09-20 1976-03-26 Fuji Photo Film Co Ltd
JPS5135696A (en) * 1974-09-20 1976-03-26 Fuji Photo Film Co Ltd
JPS53132799A (en) * 1977-04-22 1978-11-18 Fuji Photo Film Co Ltd Manufacture of strong magnetic powder
GB2080783A (en) * 1980-07-31 1982-02-10 Hercules Inc Process for producing ferromagnetic metallic particles
GB2127797A (en) * 1982-09-16 1984-04-18 Ishihara Mining & Chemical Co Process for producing magnetic powder
JPH01203226A (en) * 1988-02-10 1989-08-16 Ishihara Sangyo Kaisha Ltd Production of ferromagnetic iron oxide containing cobalt

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5135697A (en) * 1974-09-20 1976-03-26 Fuji Photo Film Co Ltd
JPS5135696A (en) * 1974-09-20 1976-03-26 Fuji Photo Film Co Ltd
JPS53132799A (en) * 1977-04-22 1978-11-18 Fuji Photo Film Co Ltd Manufacture of strong magnetic powder
GB2080783A (en) * 1980-07-31 1982-02-10 Hercules Inc Process for producing ferromagnetic metallic particles
GB2127797A (en) * 1982-09-16 1984-04-18 Ishihara Mining & Chemical Co Process for producing magnetic powder
JPH01203226A (en) * 1988-02-10 1989-08-16 Ishihara Sangyo Kaisha Ltd Production of ferromagnetic iron oxide containing cobalt

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