CN103943321A - Magnetic core and coil-type electronic element - Google Patents
Magnetic core and coil-type electronic element Download PDFInfo
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- CN103943321A CN103943321A CN201310641723.5A CN201310641723A CN103943321A CN 103943321 A CN103943321 A CN 103943321A CN 201310641723 A CN201310641723 A CN 201310641723A CN 103943321 A CN103943321 A CN 103943321A
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Abstract
The present invention aims to provide a magnetic core has excellent strength and a coil-type electronic element. The magnetic core has a core part formed by a soft magnetic body composition, and at least part of a covering layer formed on the surface of the core part; the soft magnetic body composition has a plurality of soft magnetic alloy particles, and a crystal boundary disposed among the soft magnetic alloy particles; the soft magnetic alloy particles are Fe-Si-Al series alloy particles or Fe-Si-Cr series alloy particles; and the crystal boundary is provided with a Si-containing layer.
Description
Technical field
The present invention relates to magnetic core and coil form electronic unit.
Background technology
Metallic magnetic gonosome is compared with ferrite, and existence can obtain the advantage of high saturation flux density.As such metallic magnetic gonosome, the known Fe-Si-Al of having is associated gold or Fe-Si-Cr is associated gold etc.
In patent documentation 1, propose to possess low cost and had both high permeability and the coil form electronic unit of the magnetic of magnetic flux density.
As such coil form electronic unit, can enumerate inductance component, coil component, transformer part etc. for EMC, in recent years, as the magnetic core of these electronic units, use widely by Fe-Si-Al and be associated gold or Fe-Si-Cr is associated the metallic magnetic gonosome that gold forms.
Especially, be associated gold or Fe-Si-Cr by Fe-Si-Al and be associated in the situation that metallic magnetic gonosome that gold forms uses as the magnetic core of coil form electronic unit that can realize the miniaturization of installing to the face on circuit substrate such, require the high intensity as magnetic core.
Prior art document
Patent documentation
Patent documentation 1: TOHKEMY 2011-249774 communique
Summary of the invention
The present invention is in view of such actual state, and its object is to provide magnetic core and the coil form electronic unit with excellent intensity.
In order to achieve the above object; magnetic core involved in the present invention; it is characterized in that; there is the core being formed by soft-magnetic body composition and be formed on the cover layer of surperficial at least a portion of described core; described soft-magnetic body composition has multiple non-retentive alloy particles and is present in the intergranular crystal boundary of described non-retentive alloy; described non-retentive alloy particle is that Fe-Si-Al is associated gold grain or Fe-Si-Cr is associated gold grain, at described crystal boundary, has the layer that contains Si.
In magnetic core involved in the present invention, the soft-magnetic body composition that forms core has the layer that contains Si at the crystal boundary of non-retentive alloy particle, in addition, be formed with cover layer in surperficial at least a portion of core, can bring into play thus the excellent intensity as magnetic core.
Preferably, it is characterized in that, described in contain Si layer be Si oxide skin(coating) or Si composite oxide layer.
Preferably, it is characterized in that, described in contain Si layer be also present in the surface of described non-retentive alloy particle.
Preferably, it is characterized in that, the surperficial layer that contains Si that is present in described non-retentive alloy particle is Si-Cr composite oxide layer.
In addition, coil electronic unit involved in the present invention has above-mentioned magnetic core.As coil form electronic unit, there is no particular limitation, can illustrate inductance component, the electronic unit of coil component, transformer part etc. for EMC.Especially, be applicable to realize the coil form electronic unit of the miniaturization of installing to the face on circuit substrate.
Brief description of the drawings
Fig. 1 is the summary sectional view of the related magnetic core of an embodiment of the invention.
Fig. 2 is the summary sectional view of the drum apparatus that uses of the manufacture of the related magnetic core of an embodiment of the invention.
Fig. 3 is the sectional view of the magnetic core after coil of having reeled.
Fig. 4 is the major part amplification sectional view of the core shown in Fig. 1.
Fig. 5 is the major part amplification sectional view of the core of the observation station when representing to carry out EDS and resolving.
Fig. 6 is the result of carrying out EDS parsing in the observation station shown in Fig. 5.Fig. 6 (a) is the analysis result of the related sample of embodiments of the invention 1 and 2, and Fig. 6 (b) is the analysis result of the related sample of comparative example of the present invention 3 and 4.Have, the longitudinal axis is strength ratio again, and transverse axis is the degree of depth.
Embodiment
Below, based on execution mode explanation the present invention shown in the drawings.
magnetic core
The shape of magnetic core involved in the present invention, except the drum type shown in Fig. 1, can also illustrate FT type, ET type, EI type, UU type, EE type, EER type, UI type, ring-like, kettle type, cup type etc.In the present embodiment, as shown in Figure 1, magnet 1 has drum type core shape, has the structure that is all formed with cover layer 10 on the surface of core 2.
core
Core 2 has the volume core 4 of cylinder or corner post shape and the pair of flanges portion 5 that is axially formed on both sides along this volume core 4.The external diameter of flange part 5 is larger than the external diameter of volume core 4, is formed with in the periphery of volume core 4 recess 6 being surrounded by flange part 5.Moreover, make coil component by coiling 30 being wound on to this recess 6.
The size of core 2 has no particular limits, in the present embodiment, the external diameter of volume core 4 is 0.6～1.2mm, the axial width of volume core 4 is 0.3～1.0mm, the external diameter of flange part 5 is 2.0～3.0mm, the thickness of flange part 5 is 0.2～0.3mm, is 0.5～1.0mm from outer surface to the degree of depth of the outer surface of rolling up core 4 of flange part 5.Have, the shape of flange part 5, except circle, can also be quadrangle, octagon etc. again.
Core 2 is made up of the related soft-magnetic body composition of present embodiment.
The soft-magnetic body composition that present embodiment is related; it is characterized in that; there are multiple non-retentive alloy particles and be present in the intergranular crystal boundary of described non-retentive alloy; described non-retentive alloy particle is that Fe-Si-Al is associated gold grain or Fe-Si-Cr is associated gold grain; at described crystal boundary, have the layer that contains Si.
The related soft-magnetic body composition of present embodiment is by meeting above-mentioned formation, thereby can obtain excellent magnetic characteristic, even and if also can obtain the enough intensity as magnetic core in the case of the shaping pressing formation using lower.In addition, in the time of press molding, can pass through lower shaping pressing formation, thereby can seek the further decline of the burden to mould, can improve productivity.
The soft-magnetic body composition that present embodiment is related, as shown in Figure 4, has multiple non-retentive alloy particles 21 and is present in the intergranular crystal boundary 30 of non-retentive alloy.
The layer of what present embodiment was related contain Si be present in be formed on 2 intergranular crystal boundaries 30 or be present in 3 crystal boundary 31(triple points between above particle etc.).By the existence of such layer that contains Si, even if the related magnetic core of present embodiment is in the case of the shaping pressing formation with lower, also can obtain the enough intensity as magnetic core.In addition, such layer that contains Si plays the effect of insulator by being present in crystal boundary.
The layer of what present embodiment was related contain Si is preferably Si oxide skin(coating) or Si composite oxide layer.
Have, in the present invention, oxide skin(coating) and composite oxide layer are the wide concepts that comprises amorphous layer (amorphous layer), crystallizing layer and their mixed layer again.
As the related Si oxide skin(coating) of present embodiment or Si composite oxide layer, there is no particular limitation, can enumerate the amorphous layer that for example contains Si, amorphous silicon (amorphous silicon), silicon dioxide, Si-Cr composite oxides etc.
The layer of what present embodiment was related contain Si is preferably also present in the surface of non-retentive alloy particle.This surperficial layer that contains Si that is present in non-retentive alloy particle is preferably Si-Cr composite oxide layer.There is no particular limitation for Si-Cr composite oxide layer, can enumerate amorphous layer that contains Si and Cr etc.
The layer of what present embodiment was related contain Si is preferably made up of noncrystalline.Have, a part also can be made up of crystalline again.
The thickness of the layer of what present embodiment was related contain Si is preferably 0.01～0.2 μ m, more preferably 0.01～0.1 μ m.
Have, the layer that contains Si may not form in the surperficial all modes that cover non-retentive alloy particle, also can be formed on a surperficial part for non-retentive alloy particle again.In addition, the thickness of the layer that contains Si can be inhomogeneous, and this composition can not be also homogeneous.
The layer of what present embodiment was related contain Si have or not or its thickness can by the manufacture method of described below magnetic core, control in conjunction with the kind of material or its addition, other adding ingredient, heat treatment temperature and the atmosphere gas etc. of formed body.
In the present embodiment, whether the layer that contains Si as judgement is present in the surface of non-retentive alloy particle and the method for crystal boundary, has no particular limits, for example can be by the map image of Si is resolved to judge.Below represent concrete method.
First, scan infiltration type electron microscope (STEM) by use and observe magnetic core, differentiate non-retentive alloy particle and crystal boundary.Particularly, by STEM, photographed in the cross section of dielectric layer, obtain bright-field (BF) as.Using in this bright-field picture, be present between non-retentive alloy particle and non-retentive alloy particle and the region with the contrast different with this non-retentive alloy particle as crystal boundary.The judgement whether with different contrasts can be carried out with visual, and software that also can be by carrying out image processing etc. judges.
Have again, for other elements of Cr etc., also can use the same method to make and observe map image.
The average crystallite grain diameter of the related non-retentive alloy particle of present embodiment is preferably 30～60 μ m.By average crystallite grain diameter is made as to above-mentioned scope, can easily realize the thin layer of magnetic core.
The related non-retentive alloy particle of present embodiment is that Fe-Si-Al is associated gold grain or Fe-Si-Cr is associated gold grain.
Meet above-mentioned composition by non-retentive alloy particle, the related soft-magnetic body composition of present embodiment can obtain excellent magnetic characteristic, even and if also can obtain the enough intensity as magnetic core in the case of the shaping pressing formation using lower.In addition, in the time of press molding, can pass through lower shaping pressing formation, thereby can seek the further decline of the burden to mould, can improve productivity.In addition, meet above-mentioned composition by non-retentive alloy particle, easily form at interface 30 layer that contains Si.
Fe-Si-Al is associated the composition of gold grain, and there is no particular limitation, preferably contains by Al and be scaled the aluminium (Al) of 0.5～10.5 quality %, be scaled the silicon (Si) of 4.5～14.5 quality % by Si, and surplus is made up of iron (Fe).
In non-retentive alloy particle, surplus can only be made up of iron (Fe).
Fe-Si-Cr is associated the composition of gold grain, and there is no particular limitation, preferably contains by Cr and be scaled the chromium (Cr) of 1.5～8 quality %, be scaled the silicon (Si) of 1.4～9 quality % by Si, and surplus is made up of iron (Fe).
The amount of the chromium (Cr) in non-retentive alloy particle converts and is preferably 1.5～8 quality %, more preferably 3～7 quality % by Cr.If the amount of Cr is very few, there is intensity and magnetic characteristic downward trend; If too much, there is intensity downward trend.
The amount of the silicon (Si) in non-retentive alloy particle converts and is preferably 1.4～9 quality %, more preferably 4.5～8.5 quality % by Si.The amount of Si is very few or too much, all has intensity and magnetic characteristic downward trend.
In non-retentive alloy particle, surplus can only be made up of iron (Fe).
The related soft-magnetic body composition of present embodiment, except the constituent of above-mentioned non-retentive alloy particle, also comprises the composition of carbon (C) and zinc (Zn) etc. sometimes.
Have, C is considered to come from the organic compound ingredient using in the manufacture process of soft-magnetic body composition again.In addition, Zn is considered to come from the zinc stearate adding at mould in order to reduce the pressure release of device while obtaining soft-magnetic body composition by press-powder shaping.
Amount in the related soft-magnetic body composition of present embodiment, carbon (C) is preferably less than 0.05 quality %, more preferably 0.01～0.04 quality %.If the amount of C is too much, there is the trend can not get as the enough intensity of magnetic core.
Amount in the related soft-magnetic body composition of present embodiment, zinc (Zn) is preferably 0.004～0.2 quality %, more preferably 0.01～0.2 quality %.Otherwise the amount of Zn is too much or very few, all there is the trend can not get as the enough intensity of magnetic core.
Have again, in the related soft-magnetic body composition of present embodiment, except mentioned component, can also contain inevitable impurity.
In addition, the thermal coefficient of expansion of core 2 changes according to the composition of soft-magnetic body composition, is probably 9 × 10
-6/ DEG C～10 × 10
-6/ DEG C left and right.
cover layer
As the material of cover layer 10, as long as the material with the thermal coefficient of expansion below the thermal coefficient of expansion of core 2 just has no particular limits, for example, can illustrate glass composition, SiO
2, B
2o
3, ZrO
2deng.Have, cover layer 10 can be made up of various material again, also can have the lit-par-lit structure being made up of multilayer.
In the present embodiment, cover layer 10 is preferably made up of glass composition.As glass composition, as long as the composition that is formed on the surperficial composition of core 2 using amorphous state or form as sintered glass ceramics just has no particular limits, for example can illustrate Si-B and be glass (pyrex), alkali-free glass, lead is glass etc.
The thermal coefficient of expansion of glass composition changes according to composition or the amount of each composition etc. of the contained composition of glass composition.Therefore, the thermal coefficient of expansion of glass composition is necessary to become suitably composition or the amount of set component of mode below the thermal coefficient of expansion of core 2.
Just there is no particular limitation as long as the degree of improving effect can obtain power loss is capped for cover layer 10, can be formed on surperficial at least a portion of core 2, with respect to the surface area of core 2, be formed with tectal ratio (coverage rate) and be preferably 50～100%, more preferably 90～100%.Coverage rate is higher, also larger as the effect of protective layer of breach etc. that prevents core 2.
Have again, in Fig. 1, represent the situation that coverage rate is 100%.In addition, in core 2, if be formed with cover layer 10 near the part (being recess 6 in the present embodiment) that is wound with coiling etc., easily obtain better effect.
Just there is no particular limitation as long as obtaining the thickness of the degree of improving effect of power loss for the thickness of cover layer 10, preferably exceedes 0 μ m and below 50 μ m, and more preferably 5 μ m are above and below 25 μ m.If be formed with cover layer 10, power loss is improved, if but cover layer is blocked up, because the contribution that improves effect to power loss is little, manufacturing cost increase and not preferred.In addition, if cover layer has the thickness of a certain degree, can play the function as the protective layer of core.Therefore, the thickness of cover layer 10 is preferably in above-mentioned scope.
In addition,, if cover layer 10 has insulating properties, even if core 2 is conductivity, also can guarantee the insulation with the coiling being wound.
An example of the manufacture method of the magnetic core that the cover layer 10 of the magnetic core related as present embodiment is made up of glass composition then, is described.
The related manufacture method of present embodiment preferably has: by soft-magnetic body alloy powder and the operation of mixing to obtain mixture in conjunction with material; Being dried, mixture obtains after block dry body, by this dry body being pulverized to form the operation of pelletizing; The shape that mixture or pelletizing are configured as to the compressed-core that will make obtains the operation of formed body; By being heated, obtained formed body makes harden and obtain the operation of core 2 in conjunction with material; Tectal operation before 2 formation of obtained core are burnt till; And burn till front tectal core 2 and heat-treat and form cover layer 10 and obtain the operation of magnetic core being formed with.
The compressed-core being obtained by the related manufacture method of present embodiment is made up of the related soft-magnetic body composition of above-mentioned present embodiment.
As soft-magnetic body alloy powder, can use Fe-Si-Al to be associated gold grain or Fe-Si-Cr is associated gold grain.
The shape of soft magnetic alloy powder has no particular limits, for maintaining inductance until the viewpoint in territory, highfield is preferably spherical or ellipsoid shaped.In the middle of these, for the viewpoint that further increases the intensity of compressed-core, be preferably ellipsoid shaped.In addition, the average grain diameter of soft magnetic alloy powder is preferably 10～80 μ m, more preferably 30～60 μ m.If average grain diameter is too small, there are permeability step-down and the magnetic characteristic downward trend as soft magnetic material, in addition, it is difficult that operation becomes.On the other hand, if average grain diameter is excessive, there is vortex flow to become the trend that large and abnormal loss increases.
Soft magnetic alloy powder can be obtained by the method same with the modulator approach of known soft magnetic alloy powder.Now, can modulate with gas atomization, water atomization, rotating disk method.In the middle of these, in order easily to make the soft magnetic alloy powder with desired magnetic characteristic, be preferably water atomization.
As in conjunction with material, use the combination material that comprises silicone resin.By using silicone resin as in conjunction with material, be effectively formed with the layer that contains Si at the crystal boundary of soft-magnetic body composition.Even if the magnetic core being made up of such soft-magnetic body composition, in the case of the shaping pressing formation with lower, also has enough intensity.
Have again, in the scope that does not hinder effect of the present invention, also can comprise other combination material.As other combination material, can enumerate such as various organic polymer resins, phenolic resins, epoxy resin and waterglass etc.
Can use separately silicone resin in conjunction with material, or combine to use silicone resin with other combination material.Have again, for preferably the amount of the carbon in soft-magnetic body composition (C) being restricted to the viewpoint that is less than 0.05 quality %, in conjunction with the preferably main silicone resin that uses of material.If the amount of the C in soft-magnetic body composition is too much, the intensity downward trend of the magnetic core obtaining to some extent.
According to the characteristic of needed magnetic core and difference, but preferably with respect to the soft-magnetic body alloy powder of 100 weight portions, can add 1～10 weight portion in conjunction with the addition of material, be more preferably 3～9 weight portions with respect to the soft-magnetic body alloy powder of 100 weight portions.If the addition in conjunction with material is too much, there is the trend that permeability declines and loss change is large.On the other hand, if very few in conjunction with the addition of material, there is the trend that is difficult to guarantee insulation.
The addition of silicone resin is preferably 3～9 weight portions with respect to the soft-magnetic body alloy powder of 100 weight portions.If the addition of silicone resin is very few, be difficult to form at the crystal boundary of soft magnetism composition the layer that contains Si, there is the intensity downward trend as formed products.
In addition, in described mixture or pelletizing, in the scope that does not hinder effect of the present invention, can add as required organic solvent.
As organic solvent, as long as dissolving solvent in conjunction with material, just there is no particular limitation, can enumerate the such as various solvents of toluene, isopropyl alcohol, acetone, methyl ethyl ketone, chloroform, ethyl acetate etc.
In addition, in described mixture or pelletizing, in the scope that does not hinder effect of the present invention, can add as required various additives, lubricant, plasticizer, thixotropic agent etc.
As lubricant, can enumerate such as aluminum stearate, barium stearate, dolomol, calcium stearate, zinc stearate and strontium stearate etc.They can be used singly or in combination of two or more kinds to use.In the middle of these, for the little such viewpoint of so-called resilience, preferably use zinc stearate as lubricant.
In the situation that making with lubricator, its addition is preferably 0.1～0.9 weight portion with respect to the soft-magnetic body alloy powder of 100 weight portions, is more preferably 0.3～0.7 weight portion with respect to the soft-magnetic body alloy powder of 100 weight portions.If lubricant is very few, there is the demoulding after shaping to become difficulty and easily produce the trend of shaping crackle.On the other hand, if lubricant is too much, cause the decline of shaping density, permeability reduces.
Especially, using zinc stearate as lubricant in the situation that, preferably adjust in the scope that amount in the soft-magnetic body composition obtaining, zinc (Zn) is 0.004～0.2 quality %, addition.If the amount of Zn is too much, there is the trend can not get as the enough intensity of magnetic core.
As the method that obtains mixture, there is no particular limitation, by existing known method, by soft-magnetic body alloy powder, mix to obtain with organic solvent in conjunction with material.Have again, can add as required various interpolation materials.
In the time mixing, for example, can use the comminutor of mixer or fluidized granulation machine, the rotation comminutor etc. of pressurization kneader, agitating ball mill, vibrating mill, ball mill, V mixer etc.
In addition, as the temperature and time of mixed processing, there is no particular limitation, preferably at room temperature about 1～30 minute.
As the method that obtains pelletizing, there is no particular limitation, by existing known method, after mixture is dried, dried mixture broken into pieces to obtain.
As the dry temperature and time of processing, preferably under DEG C left and right, room temperature～200 5～60 minutes.
As required, can in pelletizing, add lubricant.In pelletizing, add after lubricant, preferably mix 5～60 minutes.
As the method that obtains formed body, there is no particular limitation, preferably by existing known method, use has the shaping dies of the cavity of desired shape, filling mixture or pelletizing in this cavity, with the forming pressure of the forming temperature that specifies and regulation by this mixture compression molding.
There is no particular limitation for the molding condition of compression molding, can suitably determine according to the shape of the shape and size of soft magnetic alloy powder or compressed-core, size and density etc.For example, conventionally, maximum pressure is 100～1000MPa left and right, is preferably 400～800MPa left and right, and the time that remains maximum pressure is about 0.5 second～1 minute.
In the related manufacture method of present embodiment, by comprise silicone-based resin in conjunction with material, forming pressure can be decreased to above-mentioned maximum pressure.In addition,, even in the situation that reducing forming pressure like this, because the crystal boundary of the soft-magnetic body composition forming magnetic core is formed with the layer that contains Si, therefore magnetic core also becomes the magnetic core with enough intensity.Its result, can reduce manufacturing cost, can improve productivity and economy.
Have again, if forming pressure is too low, the densification that having being difficult to seek be shaped obtains and high permeability and be difficult to obtain the trend of enough mechanical strengths.On the other hand, too high if the shaping while shaping is pressed, there is pressure to apply the trend that effect is saturated, and have manufacturing cost to increase and the impaired trend of productivity and economy, in addition, there is easily deteriorated and durability downward trend of shaping dies.
There is no particular limitation for forming temperature, conventionally, is preferably DEG C left and right, room temperature～200.Have again, have and more promote the forming temperature while shaping, the higher trend of the density of formed body, if but the trend of the too high performance degradation that has the compressed-core that promotes the oxidation of non-retentive alloy particle and obtain, in addition, manufacturing cost increase and productivity and economy can be impaired.
The method that the formed body obtaining after being shaped is heat-treated, can be undertaken by known method, there is no particular limitation, generally speaking, preferably heat-treats to carry out by be configured as the formed body of shape arbitrarily by being shaped at the temperature of regulation with annealing furnace.
There is no particular limitation for treatment temperature when heat treatment, conventionally, is preferably 600～900 DEG C of left and right, more preferably 700～850 DEG C.Treatment temperature when heat treatment is too high or too low all the trend can not get as the enough intensity of magnetic core.
Heat treatment step is preferably carrying out containing under oxygen atmosphere gas.Here, there is no particular limitation containing oxygen atmosphere gas, can enumerate atmospheric atmosphere gas (conventionally comprising 20.95% oxygen) or with the inactive gas of argon or nitrogen etc. mix atmosphere gas etc., be preferably under atmospheric atmosphere gas.By heat-treating containing under oxygen atmosphere gas, can effectively form at the crystal boundary of soft-magnetic body composition the layer that contains Si.
In addition, the preferred shaping density of such obtained core is 5.50g/cm
3above.Be 5.50g/cm at shaping density
3when above, have densification compressed-core equal excellent trend in the such various performances of high permeability, high strength, high core resistance, low core loss.
For following obtained core 2, use the drum apparatus shown in Fig. 2, on the surface of core 2, form the cover layer 10a before the heat treatment being formed by glass composition, binder resin etc.
Drum apparatus 20 shown in Fig. 2 has the cylinder sleeve 20a of cylindric or corner post shape, and drum container 22 can rotate freely along arrow A direction (or its rightabout) inside of the hollow that is accommodated in drum apparatus 20 around its axle core.
At cylinder sleeve 20a, be formed with respectively inlet tube 23 and outlet 24.Be dried the inside that enters cylinder sleeve 20a with gas from inlet tube 23, can discharge the air of cylinder sleeve inside from outlet 24.
In the axle core position of the inside of drum container 22, there is nozzle 25 along axial arrangement, can be from nozzle 25 towards multiple cores 2 spraying slurries 26 of inside that are stored in drum container 22.Drum container 22 is along arrow A direction rotation, thereby core 2 exists with the state shown in Fig. 2, stirs by the rotation of drum container 22.
Nozzle 25 can the set spraying towards core 2 by slurry 26.Have again, can freely change the spray direction from the slurry of nozzle 25.In addition, at cylinder sleeve 20a, be connected with and omit illustrated discharge pipe, can discharge unnecessary slurry 26.
At the wall of drum container 22, be formed with and be communicated with outside with inner multiple holes, the slurry 26 that is stored in the below of cylinder sleeve 20a invades the inside of drum container 22, core 2 can be immersed in to this slurry 26.In addition, while being passed to outlet 24 from inlet tube 23 by cylinder sleeve 20a with gas, be also passed to the inside of drum container 22 dry.
In order to form the cover layer 10a before heat treatment, first, multiple cores 2 are accommodated in to the inside of the drum container 22 shown in Fig. 2.Then, drum container 22 is rotated, the set of stirring core 2 on one side, on one side from nozzle 25 spraying slurries 26, forms the cover layer 10a before heat treatment.
Slurry 26 comprises the glass powder, binder resin and the solvent that obtain by pulverizing above-mentioned glass composition.In addition also can comprise other additive.Glass composition can will form the raw material mixing, melting, cooling and become noncrystalline rapidly of non-oxidized substance etc. of oxide, halide etc. of said composition.In addition, as glass composition, also can use sintered glass ceramics.In the present embodiment, using Si-B is that glass is as glass powder.There is no particular limitation for the average grain diameter (median diameter) of glass powder, is preferably the scope below the above 10 μ m of 0.1 μ m.
The binder resin that slurry 26 comprises is preferably polyvinyl alcohol (PVA), polyvinyl alcohol resin sex change body or their mixture.By doing like this, the cover layer 10a before the heat treatment forming and the close attachment excellence of core 2.
Solvent preferably comprises water.Solvent can be only water, when the surface of glass powder and the contact angle of water are when large, preferably suppresses cohesion or the sedimentation of glass powder by sneaking into according to a certain percentage the water miscible alcohol of ethanol, isopropyl alcohol (IPA), isobutanol (IBA) etc.
The slurry 26 that sprays to core 2 forms cover each core 2 surperficial and burns till front cover layer 10a.Now, unnecessary slurry 26 is discharged from by omitting illustrated discharge pipe.From processing time of nozzle 25 spraying slurries 26, there is no particular limitation, for example, be about 30～180 minutes.In addition, although the temperature of the slurry 26 when injection depend on the composition of solvent be preferably 40 DEG C above below 100 DEG C.In the situation that using low-boiling solvent, preferably within the scope of said temperature, reduce temperature.
Then, spray slurry 26 while the dry processing of cover layer 10a before simultaneously heat-treating.In dry processing, flow into the inside of cylinder sleeve 20a by dry with gas from inlet tube 23, and discharge from outlet 24.This is dry, and to process use dry be for example the air of 50～100 DEG C with gas.After inject process, also can carry out again for example dry processing of 5～30 minutes.
After dry processing, the core 2 that is formed with the cover layer 10a before heat treatment takes out from drum container 22, carries out thermal softening processing.The softening point of the glass powder that heat-treat condition comprises according to the cover layer 10a before heat treatment etc. decides.Particularly, heat treatment temperature is preferably 600～800 DEG C, and heat treatment time is 5～120 minutes.
Heat treatment step is preferably carrying out containing under oxygen atmosphere gas.Here, there is no particular limitation containing oxygen atmosphere gas, can enumerate atmospheric atmosphere gas (conventionally comprising 20.95% oxygen) or with the inactive gas of argon or nitrogen etc. mix atmosphere gas etc.Preferably under atmospheric atmosphere gas.
After heat treatment, be formed with vitrifying on the surface of core 2 cover layer 10, obtain the ferrite core 1 shown in Fig. 1.Have, in the present embodiment, vitrifying is defined in continuous amorphous individual film becomes the state having with the rigidity of crystallization same degree again.
,, as shown in Figure 3, at the end face of a flange part 5 of each core 2, form the pair of terminal electrode 32 being formed by silver, titanium, nickel, chromium, copper etc. by printing, transfer printing, dipping, sputter, plating method etc. thereafter.Even if terminal electrode 32 cores 2 are conductivity, also owing to existing cover layer 10 to be insulated.
, coiling 30 is wound on to core 4 around thereafter, by the two ends of this coiling respectively by thermo-compressed, utilize welding, the welding etc. of ultrasonic wave or laser etc. to be connected in terminal electrode 32, complete the related coil component of an embodiment of the invention.
In the related magnetic core of present embodiment, can bring into play the excellent intensity as magnetic core.In addition, especially by forming cover layer by glass composition, can easily form cover layer on the surface of core.In addition, by being formed with by glass and forming the cover layer forming on the surface of core, can improve the intensity as magnetic core.In addition, in the situation that glass composition is insulating properties, even if core is conductivity, also can guarantee the insulating properties with the coiling etc. of reeling.
Above, embodiments of the present invention are illustrated, but the present invention is not limited to such execution mode completely, self-evident, in the scope that does not depart from purport of the present invention, can implement in various modes.
For example, in the above-described embodiment, be shaped to manufacture magnetic core (compressed-core) by mixture or pelletizing are carried out to press-powder, but also said mixture can be carried out to laminar shaping the stacked magnetic core of manufacturing.In addition, except duse process, also can obtain formed body by wet-formed, extrusion is shaped etc.
In the above-described embodiment, for crystal boundary at soft-magnetic body composition forms the layer that contains Si, use silicone resin as in conjunction with material, but also can substituted for silicon ketone resin and use the Si of silica gel or silica dioxide granule etc. to contain composition as additive.
In addition, in the above-described embodiment, core after burning till is formed to the cover layer before heat treatment, and heat-treated and form cover layer, but also can carry out burning till and tectal heat treatment of core simultaneously.By doing like this, can simplify working process.
Have again, carry out simultaneously core burn till with tectal heat treatment time heat-treat condition can be independent with core firing condition identical, also can be identical with tectal heat-treat condition.
In addition, as required, can carry out resin-dipping to formed body.Thus, can further improve the intensity of magnetic core.
In addition, in the above-described embodiment, use the related magnetic core of present embodiment as coil form electronic unit, but have no particular limits, also can suitably be used as the magnetic core of the various electronic units of motor, Switching Power Supply, DC-DC transducer, transformer, choke etc.
[embodiment]
Below, illustrate in greater detail invention by embodiment, but the present invention is not limited to these embodiment.
(embodiment 1)
about sample 1
[modulation of soft magnetic alloy powder]
First, prepare ingot bar, chunk (piece) or the pill (particle) of Fe simple substance, Cr simple substance and Si simple substance.Then by them to become Fe as 88.5 quality %, Cr as 5 quality % and Si mixes as the mode of the composition of 6.5 quality %, be accommodated in the crucible being configured in water atomization plant.Then, in torpescence atmosphere gas, use and be arranged on the actuating coil of crucible outside, by high-frequency induction by more than crucible heating to 1600 DEG C, by the ingot bar in crucible, chunk or pill melting and be obtained by mixing liquation.
Then, spray the liquation in crucible from the nozzle that is arranged on crucible, meanwhile, by make high pressure (50MPa) current collide the liquation spraying carry out cooling rapidly, make be the soft magnetic alloy powder (average grain diameter: 50 μ m) that particle forms by Fe-Si-Cr.
By fluorescent x-ary analysis, obtained soft magnetic alloy powder is carried out the result of composition analysis, can confirm consistent with the composition of preparing.
[making of core]
With respect to the soft magnetic alloy powder obtaining of 100 weight portions, add silicone resin (eastern beautiful DOW CORNING (strain) system: SR2414LV), they are at room temperature mixed 30 minutes by the kneader that pressurizes of 6 weight portions.Then, mixture is dried to 20 minutes in air at 150 DEG C.In dried Magnaglo, adding with respect to these soft magnetic alloy powders of 100 weight portions is that (day east changes into system: zinc stearate) as lubricant, mix 10 minutes by V mixer for the zinc stearate of 0.5 weight portion.
Then, obtained mixture is configured as to the dihedral sample of 5mm × 5mm × 10mm, is made into body.Have again, be shaped and press as 600MPa.By the formed body after pressurization is heat-treated 60 minutes at 750 DEG C in atmosphere, make silicone resin sclerosis, obtain magnetic core sample.
[various evaluation]
The confirmation > that the Si of < crystal boundary contains layer
First, cut off compressed-core.For this section, observe by scanning infiltration type electron microscope (STEM), carry out the differentiation of soft-magnetic body alloying pellet and crystal boundary.
Then, as shown in Figure 5, in optional observation station, use the EDS device that is attached to STEM, carry out EDS analysis.The result that EDS resolves is illustrated in Fig. 6 as skeleton diagram.Have, the longitudinal axis of Fig. 6 is by the strength ratio of measuring the characteristic X-ray obtaining again.
<3 point bending strength test (intensity) >
For compressed-core sample, in accordance with the regulation of JIS R1601, carry out 3 bending strength tests.
3 bending strengths are that test film is placed on 2 fulcrums of configuration at a certain distance, apply loading and maximum stress in bend (kg/mm while fractureing to central 1 between fulcrum
2).
In addition,, from the result of obtained maximum stress in bend, calculate the increase rate of the intensity of cover layer formation by following formula.
The increase rate (%) of intensity
=100 × (having tectal sample-intectate sample)/(intectate sample)
In the present embodiment, more than 24% be good by increase rate.Result is illustrated in table 1.
about sample 2
Style 2, except forming the cover layer before heat treatment by following method at the formed body obtaining same with sample 1, uses the method same with sample 1 to make magnetic core sample, carries out same evaluation.Represent result at table 1 and Fig. 6.
First, prepare to be used to form the powder of tectal glass composition.Using Si-B is that glass is as glass composition.Si-B is glass, and the raw material of the oxide etc. that forms glass ingredient is mixed to also melting, carries out thereafter cooling making rapidly.
Have, the Si-B using as cover layer is that the thermal coefficient of expansion of glass composition is 6 × 10 again
-6/ DEG C.The thermal coefficient of expansion of core and glass composition is measured by TMA.
Then, make the slurry using in order to form cover layer.First weight ratio, is in accordance with regulations mixed powder and the PVA of the glass composition obtaining.In addition, weight ratio is in accordance with regulations mixed the solid composition (mixture of glass powder and PVA) and the solvent that obtain, mixes and prepares slurry with ball mill.As solvent, use the solvent that has mixed water and ethanol by 8 ︰ 2.Binder resin is 10 % by weight with respect to the amount of the glass powder in slurry.
Then, in the drum container of drum apparatus, drop into formed body, all on the surface of formed body, by having used the inject process of above-mentioned slurry to form the cover layer before heat treatment.In addition, with spray side by side, under warm braw temperature 70 C, be dried processing.
, take out and be formed with tectal formed body heat treatment from drum container thereafter, by the heat treatment 1 hour at 750 DEG C of this formed body, obtain vitrifying cover layer be formed on all magnetic core samples in surface of formed body.
Tectal thickness is 3～25 μ m left and right.Have, the size before and after tectal thickness is formed by cover layer calculates again.
In addition, coverage rate is 98～100% left and right.Have, coverage rate, by being observed by visual for 20 samples, for the incomplete sample of tectal formation, is measured area coverage and is calculated again.
about sample 3
Sample 3 is except using non-silicone-based resin (long rapids changing into (strain) system: DENATITE XNR4338) as binder resin, use the method same with sample 1 to make magnetic core sample, carry out same evaluation.Result is illustrated in table 1 and Fig. 6.
about sample 4
Sample 4 is except using non-silicone-based resin (long rapids changing into (strain) system: DENATITE XNR4338) as binder resin, use the method same with sample 2 to make magnetic core sample, carry out same evaluation.Result is illustrated in table 1 and Fig. 6.
[table 1]
In sample 1 and 2, the result that STEM observes and EDS resolves, can confirm to be formed with at the crystal boundary of the soft-magnetic body composition that forms core the layer that contains Si.
Confirmed the large difference of such sample 1 and 2, whether to form the cover layer being made up of glass relevant with the surface at core, and being formed with in tectal sample 2, compared with not forming tectal sample 1, the increase rate of intensity exceedes 24%.
On the other hand, the result that STEM observes and EDS resolves, has confirmed not form in the sample 3 and 4 of layer that contains Si at the crystal boundary of the soft-magnetic body composition that forms core, compares with 2 with sample 1, and intensity is all low.
In addition,, even be formed with in tectal situation (sample 4) on the surface of core, also confirmed the raising of such intensity sharply of sample 2.
From these results, confirm in magnetic core involved in the present invention, have the layer with Si by the crystal boundary at the soft-magnetic body composition that forms core, thereby the increase rate of the intensity while forming cover layer on the surface of core increases.
Especially, the result that EDS resolves, in sample 1 and 2, has confirmed the amorphous layer that comprises Si at the crystal boundary of soft-magnetic body composition.In addition,, at particle surface, confirmed the amorphous layer (with reference to Fig. 6 (a)) that comprises Si and Cr.On the other hand, in sample 3 and 4, do not observe the layer (with reference to Fig. 6 (b)) that contains Si at the crystal boundary of soft-magnetic body composition.Such difference is considered to the difference of the increase rate of the intensity of impact in the time of the surface of core formation cover layer.
Have, the thickness of the layer that contains Si of the observation station of sample 1 and 2 is respectively approximately 0.1 μ m left and right again.
(embodiment 2)
about sample 5～8
Sample 5 except use by Fe be 85 quality %, Al be 5.5 quality % and Si be the soft magnetic alloy powder that forms forming of 9.5 quality % as soft magnetic alloy powder, use the method same with sample 1 to make compressed-core sample, carry out same evaluation.The results are shown in table 1.
Sample 6 except use by Fe be 85 quality %, Al be 5.5 quality % and Si be the soft magnetic alloy powder that forms forming of 9.5 quality % as soft magnetic alloy powder, use the method same with sample 2 to make compressed-core sample, carry out same evaluation.The results are shown in table 1.
In addition, sample 7 is that 85 quality %, Al are that 5.5 quality % and Si are that the soft magnetic alloy powder that forms forming of 9.5 quality % is as soft magnetic alloy powder except using by Fe, make compressed-core sample by the method same with sample 3, carry out same evaluation.The results are shown in table 1.
In addition, sample 8 is that 85 quality %, Al are that 5.5 quality % and Si are that the soft magnetic alloy powder that forms forming of 9.5 quality % is as soft magnetic alloy powder except using by Fe, make compressed-core sample by the method same with sample 4, carry out same evaluation.The results are shown in table 1.
As shown in table 1, in sample 5 and 6, confirm to form at crystal boundary the layer that contains Si.Therefore, be formed with in tectal sample 6 on the surface of core, compared with not forming tectal sample 5, confirmed the raising of the intensity that exceedes 24%.
On the other hand, in sample 7 and 8, do not form the layer that contains Si at crystal boundary, even be formed with in tectal situation (sample 8) on the surface of core, the also raising of the such intensity sharply to sample 6 unconfirmed.
Utilizability in industry
Magnetic core involved in the present invention is made up of the soft-magnetic body composition at crystal boundary with the layer that contains Si core, is formed with cover layer, thereby brings into play excellent intensity on the surface of this core.Especially, in the situation that making core be press-powder formed body, even press and also can obtain having the magnetic core of enough intensity with lower shaping, thereby the deteriorated of mould can be reduced, productive raising can be sought.And, by using the magnetic core of such manufacture, can reduce the manufacturing cost of coil form electronic unit.
The explanation of symbol
1 ... magnetic core
2 ... core
10 ... cover layer
10a ... cover layer before heat treatment
20 ... drum apparatus
21,22 ... non-retentive alloy particle
30,31 ... crystal boundary
Claims (5)
1. a magnetic core, is characterized in that,
To there is the core being formed by soft-magnetic body composition and be formed on the tectal magnetic core of surperficial at least a portion of described core,
Described soft-magnetic body composition has multiple non-retentive alloy particles and is present in the intergranular crystal boundary of described non-retentive alloy,
Described non-retentive alloy particle is that Fe-Si-Al is associated gold grain or Fe-Si-Cr is associated gold grain,
At described crystal boundary, have the layer that contains Si.
2. magnetic core as claimed in claim 1, is characterized in that,
The layer of the described Si of containing is Si oxide skin(coating) or Si composite oxide layer.
3. magnetic core as claimed in claim 1 or 2, is characterized in that,
The layer of the described Si of containing is also present in the surface of described non-retentive alloy particle.
4. the magnetic core as described in any one in claim 1～3, is characterized in that,
The surperficial layer that contains Si that is present in described non-retentive alloy particle is Si-Cr composite oxide layer.
5. a coil form electronic unit, is characterized in that,
There is the magnetic core described in any one in claim 1～4.
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| JP2013010845A JP6382487B2 (en) | 2013-01-24 | 2013-01-24 | Magnetic core and coil type electronic components |
| JP2013-010845 | 2013-01-24 |
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| CN110880395A (en) * | 2018-09-05 | 2020-03-13 | Tdk株式会社 | Soft magnetic composition, magnetic core, and coil-type electronic component |
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