CN100401434C - Preparation method of high-loss compound structure magnetic material - Google Patents
Preparation method of high-loss compound structure magnetic material Download PDFInfo
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- CN100401434C CN100401434C CNB2005101101759A CN200510110175A CN100401434C CN 100401434 C CN100401434 C CN 100401434C CN B2005101101759 A CNB2005101101759 A CN B2005101101759A CN 200510110175 A CN200510110175 A CN 200510110175A CN 100401434 C CN100401434 C CN 100401434C
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Abstract
The present invention relates to a preparation method for high-loss compound structured magnetic materials, which belongs to the technical field of magnetic material preparation. The present invention adopts a nitrate dissolving-gel method to prepare powder precursors, and then a hypergolic method is used for preparing nanometer crystalline ferrite powder or nanometer crystalline powder; part of the nanometer crystalline ferrite powder or nanometer crystalline powder is put in a sintering furnace to be sintered for one to two hours in the temperature of 1000 to 1400 DEG C; micrometer ferrite powder can be obtained after the furnace cooling; the nanometer crystalline ferrite powder (or nanometer crystalline powder) and micrometer ferrite powder are mixed according to a certain proportion, the mixture is ground, granulated, and pressed for forming, and then the mixture is put in the sintering furnace to be sintered for one to two hours in the temperature of 900 to 1300 DEG C, and high-loss compound structured magnetic materials can be obtained after the furnace cooling.
Description
Technical field
The present invention relates to a kind of preparation method of high-loss compound structure magnetic material, belong to the magnetic material preparing technical field.
Background technology
Ferrite be develop the earliest, oxidate magnetic material that a most widely used class has ferrimagnetism, because of its resistivity far above metallicl magnetic material, and, obtained extensive use aspect scientific and technical in radioelectronics, communication, microwave electronics and information storage and processing etc. at high frequency, pulse, microwave and optical frequency wave band.General operational requirement material excellent combination property, loss is low more good more.But to special application scenario, situation is really not so.Then require material that electromagnetic wave is had bigger loss as absorbing material.Common absorbing material has resistor-type, dielectric type and magnetizing mediums type three classes; In the magnetizing mediums type, ferrite class absorbing material is owing to its absorptivity height, and cost is low, and very big application prospect is arranged.
High loss magnetic ferrites composite construction absorbing material is one of present research topic of some scholars.Utilize nanocrystalline, microparticle composite molding, or not after the isomorphous system material non-stoichiometry composite molding, sintering prepares the special composite structure material.
After its principle is described in.
Adopt the method for " from bottom to top ", can construct nano particle, micron particles from atom, molecule; Utilize the technology of " from top to bottom ", can with macro object progressively refinement obtain nano particle.Nano particle is different fully with atom, molecule and macro object on performance, becomes a kind of novel substance state.Variation on this performance is got special value by the volume of material and is caused, so be called bulk effect.
Its surface energy of the particle of nano-scale increases greatly, and numerous surface reaction activity center is provided.In addition, surface atom has the symmetry lower than atom in the body, and surperficial spin structure is different from the body, can form non-colinear spin structure, causes the character such as magnetic, thermodynamics of nano particle to change, and anisotropy occurs.The surface atom relative scale increases, these surface atoms are in upper state, thereby show as on the nano particle macroscopic view that fusing point descends and Debye temperature descends, relative critical point changes and the caking power enhancing, simultaneously, because the coordination deficiency of nano grain surface atom, strengthened the activity of particle, made it have very strong catalytic capability, made to have the destination and make up required composite construction and become possibility.
Summary of the invention
Main points of the present invention are after fully mixing with the polycrystal magnetic oxide material (crystallite dimension is greater than 1 μ m) of nanometer technology preparation with less than the nanocrystalline magnetic oxide of 100nm, under different temperatures, carry out sintering, to solidify and structure special composite structure magnetic material.This material is functional from it, also can be called the compound high loss electromagnetic wave absorbent material of micrometer/nanometer.
Characteristics of the present invention are by sintering, are purpose to make up special composite structure, less than the nanocrystalline magnetic oxide of 100nm and crystallite dimension greater than the polycrystal micron magnetic oxide that the employing nano powder preparation technology of 1 μ m makes mix, sinter molding.Its emphasis be the special microstructural acquisition behind the sintering and the acquisition of property.
The inventive method is with merely to add nanocrystalline technology different for modification.With with natural polycrystal or with the powder after the conventional method processing with handle again after nanocrystalline material mixes different.This traditional handicraft can not effectively be controlled the size of powder granule, does not also have the repeatability of composite property.
The preparation method of a kind of high-loss compound structure magnetic material of the present invention is characterized in that having following preparation process and step:
A. raw material is equipped with: according to required proportioning take by weighing in required ferric nitrate, nickel nitrate, zinc nitrate, barium nitrate and the copper nitrate multiple metal nitrate and with the equimolar citric acid of metal nitrate, they are mixed with the aqueous solution respectively; The consumption of containing metal nitrate draws according to the mol ratio stoichiometry of its nickel-zinc ferrite in Prepared by Sol Gel Method, nickel zinc copper ferrite and barium ferrite; Be Ni
1-xZn
xFe
2O
4, 0＜x＜1 wherein; Ni
xZn
yCu
zFe
2-dO
4, 0＜x＜1,0＜y＜1,0＜z＜1,0.01＜d＜0.1 wherein, x+y+z+d=1; BaFe
12O
19
B. preparing gel: the multiple nitrate aqueous solution in citric acid, ferric nitrate, nickel nitrate, zinc nitrate, barium nitrate and the copper nitrate is added the reactor that places the constant temperature fluid bowl successively, temperature is controlled at 50～90 ℃, constant temperature stirred after 60～120 minutes, when stirring, drip the alkaline solution ethylenediamine, the pH value of regulator solution is 5～7, makes to form wet gel solution;
The preparation of c. nanocrystalline ferrite powder or nanocrystalline powder: above-mentioned wet gel solution is evaporated to remove most water, when liquid level film occurs and begins to smolder, with naked light ignite or continue the heating, this moment, gel will burn or spontaneous combustion, wait for when burning stops fully, stop heating, this moment, gel became fluffy powder russet, was nanocrystalline ferrite powder;
D. the preparation of micron ferrite powder: the above-mentioned nanocrystalline ferrite powder of part is put into sintering furnace, with per hour 130 ℃ speed intensification, and 1000～1400 ℃ of sintering temperatures 1～2 hour, the combustion back can obtain the micron ferrite powder of micro-meter scale with the stove cooling;
E. above-mentioned nanocrystalline ferrite powder for preparing and micron ferrite powder are mixed by a certain percentage, through grinding, granulation, be pressed into required form, put into sintering furnace then, with per hour 130 ℃ of speed intensifications, and 900～1300 sintering temperatures 1～2 hour, with the stove cooling, can make high-loss compound structure magnetic material then.
The preparation type of nanocrystalline ferrite powder or its selected nitrate raw material of micron ferrite powder is as follows: (a) nickel nitrate+zinc nitrate+ferric nitrate+citric acid; (b) nickel nitrate+zinc nitrate+ferric nitrate+copper nitrate+citric acid; (c) nickel nitrate+zinc nitrate+ferric nitrate+citric acid (different) with a proportioning; (d) ferric nitrate+barium nitrate+citric acid.
The advantage of the inventive method is: the ferrite powder granular size is artificially to control before complex sintered---from tens nanometers to tens micron; Compositely proportional and compound substance kind, crystalline form also can artificially be controlled; So it is that a kind of structure can be controlled, the recursive special construction magnetic material of performance preparation technology.
Description of drawings
Fig. 1 be same material nanocrystalline with the micron brilliant different proportioning samples 1
#～4
#At 980 ℃ of sintering measured magnetic spectrum after 2 hours.
Depict the relation of complex permeability and frequency among the figure, μ ' is the complex permeability real part, μ " be the complex permeability imaginary part.
Fig. 2 be same material nanocrystalline with the micron brilliant different proportioning samples 5
#～6
#At 980 ℃ of sintering measured magnetic spectrum after 2 hours.
Fig. 3 be different materials nanocrystalline with the micron brilliant different proportioning samples 1
#～4
#In 1000 ℃ of sintering measured impedance and relation of frequency after 2 hours.
Embodiment
After now embodiments of the invention being described in.
Embodiment 1: the technical process and the step of present embodiment are as follows:
(1) taking by weighing chemical purity is 98% Ni (NO
3)
26H
2O 150.22 grams; Purity is 99% Zn (NO
3)
26H
2O 101.41 grams; Purity is 98% Fe (NO
3)
39H
2O 695.68 grams, purity is 99% citric acid C
6H
8O
7H
2O 534.52 grams; 261.67ml is configured to the aqueous solution with them with deionized water.
(2) aqueous solution with citric acid, nickel nitrate, zinc nitrate, ferric nitrate adds the reactor that places thermostat successively, and temperature is controlled at 60 ℃, and constant temperature stirred 60 minutes, drips the alkaline solution ethylenediamine when stirring.Regulate pH value to 6, make to form wet gel solution, this moment, wet gel solution became blackish green.
(3) above-mentioned wet gel solution is directly heated by being put on the electric furnace, make evaporation to remove most of water, when liquid level film occurs and begins to smolder, ignite or let alone spontaneous combustion with naked light, wait for when burning stops fully, stop heating, this moment, gel became nanocrystalline ferrite powders russet, fluffy, 20～50 μ m.Here be referred to as " nanometer A nature powder ".Its chemical formula is Ni
0.4Zn
0.6Fe
2O
4
(4) the above-mentioned nanocrystalline ferrite powder of part is put into sintering furnace, heat up, and, with the stove cooling, can obtain a micron ferrite powder then 1000～1300 sintering temperatures 2 hours with 130 ℃ speed per hour.Here be referred to as " sintering micron A powder ".
(5) above-mentioned nanocrystalline ferrite powder for preparing and micron ferrite powder are mixed by a certain percentage, through grinding, granulation, be pressed into required form, put into sintering furnace then, with per hour 130 ℃ of speed intensifications, and 980 ℃ of sintering temperatures 2 hours, be incubated 2 hours again, with the stove cooling, can make compound structure magnetic material then.The size of sample and being shaped as: external diameter φ 13, internal diameter φ 7, thickness are the annular sample of 3mm.
The proportioning of sample among the embodiment 1, promptly " nanometer A spontaneous combustion powder " is as shown in table 1 with the proportioning of " sintering micron A powder ":
The proportioning table of table 1 sample
| Sample number | Mixed |
| 1 # | 50%+1100 ℃ * 2h of nanometer A nature powder sintering micron A powder 50% mixes |
| 2 # | 30%+1100 ℃ * 2h of nanometer A nature powder sintering micron A powder 70% mixes |
| 3 # | 50%+1200 ℃ * 2h of nanometer A nature powder sintering micron A powder 50% mixes |
| 4 # | 30%+1200 ℃ * 2h of nanometer A nature powder sintering micron A powder 70% mixes |
Embodiment 2: the technical process and the step of present embodiment are as follows:
(1) taking by weighing chemical purity is 98% Ni (NO
3)
26H
2O 81.97 grams; Purity is 99% Zn (NO
3)
26H
2O 148.4 grams; Purity is 98% Fe (NO
3)
39H
2O 679.82 grams; Purity is 99.5% Cu (NO
3)
23H
2O 27.36 grams; Purity is 99% citric acid C
6H
8O
7H
2O 534.52 grams; 271.38ml is configured to the aqueous solution with them with deionized water.
(2) aqueous solution with citric acid, nickel nitrate, zinc nitrate, ferric nitrate, copper nitrate adds the reactor that places thermostat successively, temperature is controlled at 60 ℃, constant temperature stirred 60 minutes, when stirring, drip the alkaline solution ethylenediamine, regulate pH value to 6, make to form wet gel solution, this moment, wet gel solution became blackish green.
(3) above-mentioned wet gel solution is directly heated by being put on the electric furnace, make evaporation to remove most of water, when liquid level film occurs and begins to smolder, ignite or let alone spontaneous combustion with naked light, wait for when burning stops fully, stop heating, this moment, gel became nanocrystalline ferrite powders brown, fluffy, 20～50 μ m.Here be referred to as " nanometer B nature powder ".Its chemical formula is Ni
0.33Cu
0.11Fe
1.97O
4
(4) the above-mentioned nanocrystalline ferrite powder of part is put into sintering furnace, heat up, and, with the stove cooling, can obtain a micron ferrite powder then 1200 ℃ of sintering temperatures 2 hours with 130 ℃ speed per hour.Here be referred to as " sintering micron B powder ".
(5) above-mentioned nanocrystalline ferrite powder for preparing and micron ferrite powder are mixed by a certain percentage, through grinding, granulation, be pressed into required form, put into inert gas atmosphere then and burn stove, with per hour 130 ℃ of speed intensifications, and 980 ℃ of sintering temperatures 2 hours, be incubated 2 hours again, with the stove cooling, can make compound structure magnetic material then.The size of sample and being shaped as: external diameter φ 13, internal diameter φ 7, thickness are the annular sample of 3mm.
The proportioning of sample among the embodiment 2, promptly " nanometer B spontaneous combustion powder " is as shown in table 2 with the proportioning of " sintering micron B powder ":
The proportioning table of table 2 sample
| Sample number | Mixed |
| 5 # | 50%+1200 ℃ * 2h of nanometer B nature powder sintering micron B powder 50% mixes |
| 6 # | 30%+1200 ℃ * 2h of nanometer B nature powder sintering micron B powder 70% mixes |
Embodiment 3: the technical process and the step of present embodiment are as follows:
(1) taking by weighing chemical purity is 98% Ni (NO
3)
26H
2O 128.43 grams; Purity is 99% Zn (NO
3)
26H
2O 126.41 grams; Purity is 98% Fe (NO
3)
29H
2O 693.72 grams; Purity is 99% citric acid C
6H
8O
7H
2O 533.02 grams; 262.8ml is configured to the aqueous solution with them with deionized water.
(2) aqueous solution with citric acid, nickel nitrate, zinc nitrate, ferric nitrate adds the reactor that places thermostat successively, temperature is controlled at 60 ℃, constant temperature stirred 60 minutes, when stirring, drip the alkaline solution ethylenediamine, regulate pH value to 6, make to form wet gel solution, this moment, wet gel solution became blackish green.
(3) above-mentioned wet gel solution directly is put on the electric furnace heats, make evaporation to remove most of water, when film appears in liquid level, ignite or let alone spontaneous combustion with naked light, Deng the burning stop after, this moment gel become spinel type ferrite nanocrystalline powders brown, fluffy, 20～50 μ m.Here be referred to as " powder C ".Its chemical formula is Ni
0.5Zn
0.5Fe
2O
4
(4) getting chemical purity is 98% Fe (NO
2)
39H
2O 69.72 grams; Purity is 99.5% Ba (NO
3)
235.45 gram; Purity is 99% citric acid C
6H
8O
7H
2O 370.52 grams; 280ml is configured to the aqueous solution with them with deionized water.
(5) aqueous solution with citric acid, ferric nitrate, barium nitrate adds the reactor that places thermostat successively, temperature is controlled at 60 ℃, constant temperature stirred 60 minutes, when stirring, drip the alkaline solution ethylenediamine, regulate pH value to 6, make to form wet gel solution, this moment, wet gel solution became blackish green.
(6) above-mentioned wet gel solution directly is put on the electric furnace heats, make evaporation to remove most of water, when film appears in liquid level, ignite or let alone spontaneous combustion with naked light, Deng the burning stop after, this moment gel become nanocrystalline powders brown, fluffy, 20～50 μ m.
(7) above-mentioned nanocrystalline powder is put into sintering furnace, heat up, and, be incubated 2 hours again,, obtain the brilliant magneto plumbite type ferrite powder of micron then with the stove cooling 1100 ℃ of sintering temperatures 2 hours with 130 ℃ speed per hour.Here be referred to as " powder D ".Its chemical formula is BaFe
12O
19
(8) above-mentioned nanocrystalline spinel stone type ferrite powder C and the brilliant magneto plumbite type ferrite powder D of micron are mixed by following proportioning, as shown in table 3 below:
Table 3 nanometer crystalline Ni
0.5Zn
0.5Fe
2O
4(C) and the micron brilliant BaFe
12O
19(D) mixing ratio
| The sample label | C: D (mass ratio) |
| 1 # | 9∶1 |
| 2 # | 8∶2 |
| 3 # | 7∶3 |
| 4 # | 6∶4 |
(9) with the powder of above-mentioned mixing, through grind, after the granulation, being pressed into external diameter φ 13, internal diameter 7, thickness is the annular sample of 3mm, heat up with 130 ℃ of speed per hour, and, be incubated 2 hours again 1000 ℃ of sintering temperatures 2 hours, with the stove cooling, make high-loss compound structure magnetic material then.
From Fig. 1, Fig. 2, as seen, represent the magnetic permeability imaginary part μ of magnetic loss " peak value, increase with bulky grain size powder ratio, move (among Fig. 1, from 70MHz to 40MHz) to low frequency gradually after complex sintered, and very regular.The loss meeting of this sandwich changes to some extent with the material category difference.For example among the embodiment 3, its compound nanocrystalline powder is to have the face-centered cubic spinel structure, and a compound micron crystalline flour body is the magneto-plumbite type structure that belongs to hexaplanar, and these two kinds isomorphous system material nano crystalline substance, micron are brilliant not compound, have shown the impedance that it is great, controlled.This can see from Fig. 3.
The high-loss compound structure magnetic material that the inventive method makes, functional from it, also can be called the compound high loss electromagnetic wave absorbent material of micrometer/nanometer.
Claims (2)
1. the preparation method of a high-loss compound structure magnetic material is characterized in that having following preparation process and step:
A. raw material is equipped with: according to required proportioning take by weighing in required ferric nitrate, nickel nitrate, zinc nitrate, barium nitrate and the copper nitrate multiple metal nitrate and with the equimolar citric acid of metal nitrate, they are mixed with the aqueous solution respectively; The consumption of containing metal nitrate draws according to the mol ratio stoichiometry of its nickel-zinc ferrite in Prepared by Sol Gel Method, nickel zinc copper ferrite and barium ferrite; Be Ni
1-xZn
xFe
2O
4, 0＜x＜1 wherein; Ni
xZn
yCu
zFe
2-dO
4, 0＜x＜1,0＜y＜1,0＜z＜1,0.01＜d＜0.1 wherein, x+y+z+d=1; BaFe
12O
19
B. preparing gel: the multiple nitrate aqueous solution in citric acid, ferric nitrate, nickel nitrate, zinc nitrate, barium nitrate and the copper nitrate is added the reactor that places the constant temperature fluid bowl successively, temperature is controlled at 50～90 ℃, constant temperature stirred after 60～120 minutes, when stirring, drip the alkaline solution ethylenediamine, the pH value of regulator solution is 5～7, makes to form wet gel solution;
C. the preparation of nanocrystalline ferrite powder: above-mentioned wet gel solution is evaporated to remove most water, when liquid level film occurs and begins to smolder, with naked light ignite or continue the heating, this moment, gel will burn or spontaneous combustion, wait for when burning stops fully, stop heating, this moment, gel became fluffy powder russet, was nanocrystalline ferrite powder;
D. the preparation of micron ferrite powder: the above-mentioned nanocrystalline ferrite powder of part is put into sintering furnace, with per hour 130 ℃ speed intensification, and,, can obtain the micron ferrite powder of micro-meter scale then with the stove cooling 1000～1400 ℃ of sintering temperatures 1～2 hour;
E. above-mentioned nanocrystalline ferrite powder for preparing and micron ferrite powder are mixed by a certain percentage, through grinding, granulation, be pressed into required form, put into sintering furnace then, with per hour 130 ℃ of speed intensifications, and 900～1300 ℃ of sintering temperatures 1～2 hour, with the stove cooling, can make high-loss compound structure magnetic material then.
2. the preparation method of a kind of high-loss compound structure magnetic material as claimed in claim 1 is characterized in that the preparation type of described nanocrystalline ferrite powder or its selected nitrate raw material of micron ferrite powder is as follows:
(a) nickel nitrate+zinc nitrate+ferric nitrate+citric acid; (b) nickel nitrate+zinc nitrate+ferric nitrate+copper nitrate+citric acid; (c) nickel nitrate+zinc nitrate+ferric nitrate+citric acid, different with (a) proportioning; (d) ferric nitrate+barium nitrate+citric acid.
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| CN102898147A (en) * | 2012-11-05 | 2013-01-30 | 西华师范大学 | Environment-coordinating method for preparing titanate piezoelectric ceramic powder |
| CN104525967B (en) * | 2014-12-17 | 2017-01-04 | 北京科技大学 | A kind of method preparing nanometer iron powder |
| CN107737917B (en) * | 2017-09-27 | 2019-08-16 | 西安理工大学 | A kind of preparation method of sheet suede structure magnetism microwave absorption |
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| CN1486958A (en) * | 2003-04-01 | 2004-04-07 | 上海大学 | Prepn of doped magnetic ferrite material |
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| CN1486958A (en) * | 2003-04-01 | 2004-04-07 | 上海大学 | Prepn of doped magnetic ferrite material |
Non-Patent Citations (2)
| Title |
|---|
| 粒级组配工艺制备高磁导率Ni-Cu-Zn铁氧体. 王依琳等.无机材料学报，第19卷第4期. 2004 |
| 粒级组配工艺制备高磁导率Ni-Cu-Zn铁氧体. 王依琳等.无机材料学报，第19卷第4期. 2004 * |
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