CN102319895A - Clad powder for powdered iron core and preparation process for clad powder - Google Patents
Clad powder for powdered iron core and preparation process for clad powder Download PDFInfo
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- CN102319895A CN102319895A CN201110308022A CN201110308022A CN102319895A CN 102319895 A CN102319895 A CN 102319895A CN 201110308022 A CN201110308022 A CN 201110308022A CN 201110308022 A CN201110308022 A CN 201110308022A CN 102319895 A CN102319895 A CN 102319895A
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Abstract
The invention discloses clad powder for a powdered iron core and a preparation process for the clad powder. The clad powder for the powdered iron core is prepared by adopting a ball milling method; the clad powder contains iron powder, organic insulating agent and lubricating agent serving as raw materials; and particularly, an inorganic nano oxide is added in the clad powder. In the preparation process, insulated cladding of the powder is realized, meanwhile, organic resin is effectively modified by nano particles, and the heat resistant temperature of the organic resin is improved; and in high-temperature annealing of the subsequent powdered iron core product, completeness of an insulated film is kept, thermal decomposition of the powdered iron core is reduced, and the annealing temperature is improved. The clad powder has good process properties such as forming property, flowability and the like; the powdered iron core with high compactness and great improvement on mechanical property and magnetic conductivity can be stamped by using the clad powder as a raw material; the utilization rate of the raw material is high; the powdered iron core has the same orientation in each direction and is more convenient for three-dimensional shape machining of a subsequent product with low cost; and the subsequent machined product can reduce eddy current loss when used in a high-frequency area of an alternating-current external field, and can partially replace the traditional laminated iron core.
Description
Technical field
The invention belongs to the function field of new, relate to a kind of dust core, adopt cladding powder of the present invention to be used to make the dust core of magnetic core, motor and other electronic units in transformer and the inductor with cladding powder and preparation technology thereof.
Background technology
Now on the market ferrocart core mainly to adopt the folded silicon steel slice with punching press be silicon steel plate, cores pile in layers is processed in machined again, is used to make the iron core of range transformer, motor and generator.Silicon steel sheet is claimed electrical sheet again, is a kind of low silicon-iron soft magnetic alloy of carbon electrode that contains, and general silicon content is 0.5～4.5%; The iron core magnetic conductivity of selecting for use silicon steel sheet to process is big, iron loss is low; Be widely used, but preparation technology is loaded down with trivial details, needs punching press and can not once-forming; Utilization rate of raw materials is low, is difficult to realize automation; Silicon steel sheet has certain orientation, needs the rapid technology of multistep can produce the iron core product of required 3D shape.
With the folded silicon steel slice of punching press be silicon steel plate, there is a significant limitation in the cores pile in layers processed of machined again; Be exactly on the plane of lamination steel magnetic property fine; But it is poor at its vertical direction magnetic property; Because the limitation of magnetic property anisotropic and stamping technology, force the lamination motor can only apply to the parts of two-dimentional magnetic flux and can't on three-dimensional motor, use; Simultaneously because the lamination steel often has sharp-pointed outstanding arris, and the surface is comparatively coarse, thus for the protection winding needs tough and tensile abundant insulating barrier must be around more copper cash, so both waste materials (copper cash), increasing of insulating barrier can cause the heat conduction to reduce simultaneously.
The preparation of iron Si-Al Magnetic Powder Core and permalloy powder core, high magnetic flux powder core can adopt that powder metallurgical technique is disposable to shape; Stock utilization is high; Be expected to the alternative layer stack iron core; But because corresponding ferrocart core is low with the cladding powder magnetic conductivity, cost an arm and a leg, can not the alternative layer stack iron core in actual production and extensive use.
With regard to the preparation dust core, there is different processing methods that straight iron powder is prepared into the flat powder particle, like various forms of iron powders through electrolysis and water atomization prepared.But the electrolytic powder processing cost is higher, and iron powder purity is not high, and oxygen content in power surpasses 0.6%, and the iron core mechanical performance that is prepared into can not satisfy processing request; Water atomization powder process powder morphology is irregular, and the iron core magnetic property that is prepared into is stable inadequately, therefore is inappropriate for the substitute that is used as cores pile in layers.
Therefore, producing the cladding powder that is suitable for preparing dust core is the important channel of alternative layer stack iron core.
21 century, motor developed to microminiaturized direction, and the high frequencyization of inevitable requirement magnetic device forces magnetic device to develop to directions such as miniaturization, intellectuality, highly integrated, high density and ultrafast transmission speeds.In order to comply with the trend that reduces the electronic equipment size, dust core is had higher requirement, require dust core fine and close and effective.The magnetic conductivity of pure iron magnetic core powder big (22-100H/m), being prepared into dust core can be reduced in size, and this makes motor miniaturization, lightweight become possibility, but because the resistivity of iron powder is low by (10
-8The Ω m order of magnitude), eddy-current loss is big when in exchanging the outfield high frequency region, using, and therefore need evenly coat one deck dielectric film to improve the resistivity of magnetic core at powder particle surface, reduces eddy-current loss.Method commonly used is to adopt chemical coating method to cover one deck insulating coating at powder particle surface.And in the preparation process of dust core, impose bigger pressing pressure cladding powder is shaped to improve the density of magnetic core, there is bigger internal stress in the pressed compact inevitably; In order to discharge residual stress in the pressed compact with the mechanical property that improves the magnetic core, the magnetic property that improves the magnetic core; Need carry out annealing in process, temperature and adopts above-mentioned chemistry to coat the cladding powder that legal system is equipped with generally between 400-600 ℃; In follow-up heat treatment process; The insulating coating that is coated on particle surface is generally organic insulating film, in annealing process, unavoidably can decompose carbonization, thereby worsens the magnetic property of magnetic core; And then eddy-current loss strengthens when causing again in exchanging the outfield high frequency region, using, and does not have effectively solution so far.Therefore, chemistry coats legal system and is equipped with cladding powder and has certain shortcoming and can't apply.
He Genasi is maximum in the world, a most experienced iron-based powder production group; The Somaloy series powder that the said firm produces is a kind of cladding powder that is suitable for preparing dust core; But in practical application, by the dust core that Somaloy series powder time processing is shaped and prepares, mechanical property is not good; Pressing pressure limit, arrisdefect phenomenon occur falling easily less than 400MPa; If dust core temperature in heat treatment process surpasses 500 ℃, the organic resin that is added in the Somaloy series powder can decompose combination properties such as the mechanical property of grievous injury dust core, magnetic property in a large number; Somaloy series powder price is expensive in addition, these a series of effects limit applying of cladding powder, make dust core can not substitute traditional cores pile in layers.
In sum; Seek a kind ofly to be used for dust core (magnetic core) preparation and cost is low, the cladding powder of powder technology excellent performance and preparation technology thereof have great importance; Be that dust core substitutes traditional cores pile in layers, prepare the key point of compact conformation, isotropic three-dimensional magnetic flux.
Summary of the invention
To the defective that above-mentioned prior art exists, the object of the present invention is to provide a kind of processing performance good, be beneficial to the one-shot forming of subsequent product dust core and significantly improve the dust core density, improve its related mechanical properties, reduce its eddy-current loss of in exchanging the outfield high frequency region, using, strengthen its magnetic property and dust core with low cost with cladding powder and preparation technology thereof.
Technical solution of the present invention is following:
Dust core of the present invention may further comprise the steps with the preparation technology of cladding powder:
Earlier iron powder, organic insulation agent, lubricant are mixed, wherein the iron powder quality accounts for more than 93% of total amount, and it is the inorganic nanometer oxide of iron powder quality 3%-6% that the back adds mass fraction, mixes;
Vacuumize after pouring said mixture into ball grinder, vacuum is less than 10
-2Pa;
Carry out ball milling subsequently, rotational speed of ball-mill keeps 400-450r/min, ball milling time remaining 3-5h, and ratio of grinding media to material is 10: 1-12: 1, ball-milling medium is an ethanolic solution; Abrading-ball selects for use diameter to be respectively two kinds of stainless steel balls of 4mm, 6mm; The mass ratio of two kinds of particle diameter stainless steel balls is 1.5: 1-1: 1;
Above-mentioned cladding powder is cooled to room temperature, final drying.
Further specify, said iron powder is a straight iron powder, and average grain diameter is 80-120 μ m, and oxygen content in power is no more than 0.3%.
Further specify, said organic insulation agent is the heat resistant type modified epoxy, and heat resisting temperature can reach 500 ℃, and its mass fraction is the 1%-3% of iron powder quality;
Further specify, said lubricant can be selected stearic acid, zinc stearate, barium stearate for use, and its mass fraction is the 0.5-1.5% of iron powder quality.
Further specify, the mass ratio of said inorganic nanometer oxide and heat resistant type modified epoxy is 2.5: 1.
Said inorganic nanometer oxide is the Nano sol via the pre-dispersed processing of ultrasonic wave.
Said Nano sol is nanometer ZrO
2Colloidal sol, wherein the particle diameter of nano particle is 40-50nm, its mass fraction is the 3%-6% of iron powder quality.
Dust core of the present invention by above-mentioned prepared is used cladding powder; Contain iron powder, organic insulation agent and lubricant, also contain inorganic nanometer oxide, said cladding powder particle diameter is 80-120 μ m; Oxygen content is no more than 0.3%, and particle surface coats one deck dielectric film.
Dust core of the present invention is used cladding powder; Powder is ground into the flat particle; Particle diameter moderate (average grain diameter is 80-120 μ m), powder purity high (oxygen content is no more than 0.3%), processing performances such as the flowability of powder, formability are excellent thus; In exchanging the outfield, be prone to tend to the principal plane direction, magnetic property is preferable; And; In mechanical milling process, realized that not only the insulation of powder particle coats, simultaneously because nano-particles size is little, specific area is big, surperficial non-matching atom is many; Thereby combine ability strong with polymer; Resin matrix there is special effect, has strong physical absorption and chemical crosslinking effect between the particulate of nanometer scale and the organic facies on the one hand, thereby improved the energy that the molecular resin chain needs in the heating process cleaved; On the other hand inorganic nano-particle be different from resin can be at hot stage generation pyrolysis devolatilization, thereby increase the hot residual rate of resin at hot stage.Make the content of inorganic nano-particle become certain multiple relation with the content of ordinary resin, can more effectively improve the heat resisting temperature of organic resin.Therefore, inorganic nanometer powder both can be optimized covered effect as a kind of inorganic insulation agent, again can modified epoxy, improve the heat resisting temperature of organic resin, and reduce the thermal decomposition of dust core in high-temperature annealing process, improve annealing temperature.The dielectric film that is coated on powder particle surface is still complete, has improved the mechanical property of dust core greatly, has improved the magnetic property of dust core.
Therefore; Only need cladding powder of the present invention is applied bigger pressure; Just can go out the high dust core of density through the mold pressing processing and manufacturing at normal temperatures; Improve mechanics, the mechanical performance of dust core simultaneously, and improved the magnetic conductivity of dust core, thus the eddy-current loss when reducing it and in exchanging the outfield high frequency region, using; Dust core is orientated identical on all directions, makes it satisfy the requirement that following process becomes 3D shape, can design products such as three-dimensional motor in high flexible ground, and smooth surface, can reduce the thickness of insulating barrier, can either save copper cash, also can improve the heat conduction.Meanwhile; The manufacturing process of dust core is simple, and has avoided special pressing modes such as temperature and pressure, high temperature insostatic pressing (HIP), isostatic cool pressing, and utilization rate of raw materials is high, environmental pollution is little; Reduced the cost of dust core; Produce immeasurable beneficial effect, can partly substitute traditional cores pile in layers, had important market value.
Description of drawings
Accompanying drawing is preparation technology's flow chart of cladding powder of the present invention.
The specific embodiment
Below in conjunction with accompanying drawing and embodiment the present invention is described further.
(1) be that 1: 1%: 1.5% iron powder, epoxy powder, zinc stearate powder mixes with weight ratio earlier, wherein the iron powder quality accounts for 97.6% of total amount; Add again via the pre-dispersed processing of ultrasonic wave nanometer ZrO
2Colloidal sol, its mass fraction is 3% of an iron powder quality, after mixing, adds the ethanol abrasive media and pours into together in the ball grinder of planetary ball mill, vacuumizes immediately, vacuum is 0.8 * 10
-2Pa; Abrading-ball selects for use diameter to be respectively two kinds of stainless steel balls of 4mm, 6mm, and ratio of grinding media to material is 12: 1; Mass ratio little, big abrading-ball is 1.5: 1.Be cooled to room temperature after then rotating 3h at a high speed, carry out dried at last, obtain cladding powder of the present invention with 450r/min.Wherein, iron powder has realized that the insulation between the particle coats, and iron powder is ground into the suitable flakelike powder of particle diameter simultaneously.
Straight iron powder particle diameter in the raw material is 100 μ m, and oxygen content is 0.2%.
This cladding powder is prepared into dust core, and gained dust core magnetic property is better, and saturation flux density has reached 1.4T, and compression strength can satisfy processing request for 430MPa, can be used for the 3D flux path of new layout.
(2) weight ratio is 1: 2%: 1% straight iron powder, epoxy powder, barium stearate powder mixes after, add quality and be the iron powder quality 5%, through the nanometer ZrO of the pre-dispersed processing of ultrasonic wave
2Colloidal sol after mixing, adds the ethanol abrasive media and pours into together in the ball grinder of planetary ball mill, vacuumizes immediately, and vacuum is 0.9 * 10
-2Pa; Abrading-ball is selected the stainless steel ball of two kinds of particle diameters for use; Ratio of grinding media to material is 10: 1, the same example of size, and the mass ratio of two kinds of particle diameter stainless steel balls is 1.2: 1; Be cooled to room temperature after rotating 4h at a high speed with 420r/min; Carry out dried at last, iron powder has realized that the insulation between the particle coats, and iron powder is ground into the suitable flakelike powder of particle diameter simultaneously.
Straight iron powder particle diameter in the raw material is 100 μ m, and oxygen content is less than 0.3%.
Adopt the cladding powder of aforesaid way preparation to be processed into dust core, mechanical property is better, and compression strength has reached 500MPa, and saturation flux density is 1.2T, can be used for built-in magnetic part, takes turns etc. as askew.
(3) be after 1: 1.5%: 0.5% straight iron powder, epoxy powder, stearic acid powder mixes with weight ratio, add quality and be the iron powder quality 3.75%, through the nanometer ZrO of the pre-dispersed processing of ultrasonic wave
2Colloidal sol after mixing, adds the ethanol abrasive media and pours into together in the ball grinder of planetary ball mill, vacuumizes immediately, and vacuum is 0.9 * 10
-2Pa; Abrading-ball such as selects for use at two kinds of stainless steel balls of quality, and ratio of grinding media to material is 12: 1, and the same example of size is cooled to room temperature after rotating 2.5h at a high speed with 440r/min, carries out dried at last.
Adopt the cladding powder of aforesaid way preparation to be processed into dust core, mechanical property is better, and compression strength has reached 450MPa, and saturation flux density is 1.3T, can be used for the ABS oil pump motor.
Claims (10)
1. a dust core may further comprise the steps with the preparation technology of cladding powder:
Earlier iron powder, organic insulation agent, lubricant are mixed, wherein the iron powder quality accounts for more than 93% of total amount, and it is the inorganic nanometer oxide of iron powder quality 3%-6% that the back adds mass fraction, mixes; Vacuumize after pouring said mixture into ball grinder, vacuum is less than 10
-2Pa; Carry out ball milling subsequently, rotational speed of ball-mill keeps 400-450r/min, ball milling time remaining 3-5h, and ratio of grinding media to material is 10: 1-12: 1, ball-milling medium is an ethanolic solution; Abrading-ball is selected two kinds of particle diameter stainless steel balls for use; Above-mentioned cladding powder is cooled to room temperature, final drying.
2. dust core according to claim 1 is with the preparation technology of cladding powder; It is characterized in that: said iron powder is a straight iron powder; Average grain diameter is 80-120 μ m; Oxygen content in power is no more than 0.3%, and said lubricant can be selected stearic acid, zinc stearate, barium stearate for use, and its mass fraction is the 0.5-1.5% of iron powder quality.
3. dust core according to claim 1 and 2 is characterized in that with the preparation technology of cladding powder: said inorganic nanometer oxide is the Nano sol via the pre-dispersed processing of ultrasonic wave.
4. dust core according to claim 3 is characterized in that with the preparation technology of cladding powder: said Nano sol is nanometer ZrO
2Colloidal sol, wherein the particle diameter of nano particle is 40-50nm, its quality is the 3%-6% of iron powder quality.
5. dust core according to claim 1 and 2 is characterized in that with the preparation technology of cladding powder: said organic insulation agent is the heat resistant type modified epoxy, and heat resisting temperature can reach 500 ℃, and its quality is the 1%-3% of iron powder quality.
6. dust core according to claim 3 is with the preparation technology of cladding powder; It is characterized in that: said organic insulation agent is the heat resistant type modified epoxy; Heat resisting temperature can reach 500 ℃; Its mass fraction is the 1%-3% of iron powder quality, and the mass ratio of said inorganic nanometer oxide and heat resistant type modified epoxy is 2.5: 1.
7. dust core according to claim 1 and 2 is characterized in that with the preparation technology of cladding powder: said abrading-ball selects for use diameter to be respectively two kinds of stainless steel balls of 4mm, 6mm, and the mass ratio of two kinds of particle diameter stainless steel balls is 1.5: 1-1: 1.
8. dust core according to claim 1 and 2 is with the cladding powder of cladding powder preparation technology preparation, and it is characterized in that: said cladding powder is a flat, and particle diameter is 80-120 μ m, and oxygen content is no more than 0.3%, and particle surface coats one deck dielectric film.
9. according to the cladding powder of any described dust core in the claim 3,5,7,8 with cladding powder preparation technology preparation; It is characterized in that: said cladding powder is a flat; Particle diameter is 80-120 μ m, and oxygen content is no more than 0.3%, and particle surface coats one deck dielectric film.
10. dust core according to claim 6 is with the cladding powder of cladding powder preparation technology preparation, and it is characterized in that: said cladding powder is a flat, and particle diameter is 80-120 μ m, and oxygen content is no more than 0.3%, and particle surface coats one deck dielectric film.
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| CN201110308022A CN102319895A (en) | 2011-10-12 | 2011-10-12 | Clad powder for powdered iron core and preparation process for clad powder |
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| CN201110308022A CN102319895A (en) | 2011-10-12 | 2011-10-12 | Clad powder for powdered iron core and preparation process for clad powder |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013159558A1 (en) * | 2012-04-26 | 2013-10-31 | The Hong Kong University Of Science And Technology | Soft magnetic composite materials |
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| CN1343990A (en) * | 2000-09-08 | 2002-04-10 | Tdk股份有限公司 | Powder pressed iron core |
| JP2004146804A (en) * | 2002-09-30 | 2004-05-20 | Hitachi Powdered Metals Co Ltd | Manufacturing method for dust core |
| JP2005317937A (en) * | 2004-03-31 | 2005-11-10 | Kyocera Chemical Corp | Dust core and method of producing the same |
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|---|---|---|---|---|
| JPS6272102A (en) * | 1985-09-26 | 1987-04-02 | Kawasaki Steel Corp | Iron powder for magnetic dust core used at high frequency and manufacture thereof |
| JPH09320830A (en) * | 1996-05-28 | 1997-12-12 | Hitachi Ltd | Manufacture of magnetic powder for dust core |
| CN1198579A (en) * | 1997-03-31 | 1998-11-11 | Tdk株式会社 | Powder moulded iron core, ferromagnetic powder composition and preparation process thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013159558A1 (en) * | 2012-04-26 | 2013-10-31 | The Hong Kong University Of Science And Technology | Soft magnetic composite materials |
| US20150050178A1 (en) * | 2012-04-26 | 2015-02-19 | The Hong Kong University Of Science And Technolog | Soft Magnetic Composite Materials |
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Application publication date: 20120118 |