CN102693826A - Powder magnetic core and manufacture method thereof - Google Patents

Abstract

The invention is to provide a powder magnetic core and a manufacture method thereof, wherein the heat-resistant performance of initial permeability is enhanced. The mixture containing soft magnetic powder (5) and insulating adhesive material (6) is compressed and heated to obtain the powder magnetic core; and the characteristic is that the insulating adhesive material (6) possesses adhesive resin and glass, and the glass transition temperature (Tg) of the glass is lower than the heating process temperature. According to the powder magnetic core and its manufacture method provided in the utility model, the heat-resistant performance of initial permeability is enhanced. In addition, the initial permeability is enhanced by adding glass and magnetic particals smaller than soft magnetic powder to the insulating adhesive material, the heat-resistant performance of initial permeability and iron loss is enhanced.

Description

Dust core and manufacturing approach thereof

Technical field

The present invention relates to have soft magnetic powder and insulating properties jointing material and be used for the dust core and the manufacturing approach thereof of choking-winding etc.

Background technology

For for the dust core of the uses such as reactor, transformer and choking-winding of the booster circuit that is used for hybrid motor vehicle etc. or generating, converting equipment; Suppose under its environment that is in the condition of high temperature for a long time, require it to have the thermal stability of magnetic characteristic.

Dust core can be shaped and further apply heat treatment and obtain through the mixture with soft magnetic powder and jointing material (binding resin) being carried out press-powder.This heat treatment is for the required processing of the magnetic characteristic of improving soft magnetic powder,, resin of good heat stability etc. is being studied aspect the binding resin use for this reason.

Yet, can know according to current experiment, for the structure of in the past dust core, produced the problem that the permeability deterioration increases, the thermal stability of inductance descends through heat resistant test.

[technical literature formerly]

[patent documentation]

[patent documentation 1] TOHKEMY 2010-251600 communique

[patent documentation 2] TOHKEMY 2010-232223 communique

[patent documentation 3] TOHKEMY 2009-212385 communique

[patent documentation 4] TOHKEMY 2004-143554 communique

[patent documentation 5] TOHKEMY 2010-27854 communique

[summary of invention]

[problem that invention will solve]

Patent documentation 1 is with the invention of powder about the dust core of insulating barrier that disperses glass powder to the alcoxide layer that covers soft magnetic metal powder and possess further covering alcoxide layer.In addition, in the invention of patent documentation 1 record, its purpose is to obtain high-intensity dust core.

Patent documentation 2 is about the core part with soft magnetic material, will covers the invention that the insulant of the coating that the particle adhesion of the insulating properties material of core part forms covers soft magnetic powder.In addition, in the invention of patent documentation 2 record, its purpose is the dust core that provides eddy current losses little.

Patent documentation 3 is the inventions about the composite soft magnetic material with soft magnetic powder and insulating properties jointing material; It has put down in writing following content; That is, the insulating properties jointing material is a crown glass, can add any a kind in silicone resin, the stearate to said composite soft magnetic material.In addition, in the invention of patent documentation 3 records, its purpose is the performance of long term maintenance dust core.At this, can enumerate out iron loss and intensity at aspect of performance.

Patent documentation 4 is about utilizing the invention of the covering iron-based powder that lining material forms the iron-based powder surface coverage, its put down in writing said lining material for through have beyond glass, adhesive and glass and the adhesive have insulating properties, the thermal stability material constitutes.In addition, in the invention of patent documentation 4 record, its purpose is to obtain the dust core that can guarantee that insulating properties and intensity are improved.

Patent documentation 5 discloses following content; Promptly; Amorphous soft magnetic alloy powder and glass powder are mixed with resin of binding property; With they the mixture press molding and process formed body, heat-treat with the temperature lower and form dust core than the crystallized temperature of amorphous soft magnetic alloy powder.In addition, in the invention of patent documentation 5 records, its purpose is to obtain the dust core of low loss.

As stated, in each patent documentation, do not exist requirement to possess the document of the thermal stability of permeability.In addition, do not exist for the thermal stability of permeability the material formation of jointing material and the patent documentation that has carried out improvement with heat treated relation yet.In the invention that patent documentation 5 is put down in writing, put down in writing experiment about iron loss and permeability.Yet patent documentation 5 is first purpose to reduce eddy current losses, is not to improve to jointing material and with heat treated relation etc. from the viewpoint of permeability.In addition, what can expect is, under the experiment condition of patent documentation 5, the addition of jointing material (resin of binding property) is very few and can not fully guarantee the intensity of dust core.

Summary of the invention

Therefore, the present invention accomplishes in order to solve above-mentioned problem in the past, and its purpose is to provide the dust core and the manufacturing approach thereof of the thermal stability that especially can improve permeability.

The mixture compression molding and heat-treat of dust core of the present invention through will having soft magnetic powder and insulating properties jointing material obtains, it is characterized in that,

Said insulating properties jointing material has binding resin and glass,

The glass transformation temperature of said glass (Tg) is lower than said heat treated temperature.

In addition, the manufacturing approach of dust core of the present invention is characterised in that, comprising:

With soft magnetic powder, mix and generate the operation of mixture as the binding resin of insulating properties jointing material and glass powder,

With said mixture compression molding, the operation to heat-treat then than the high heat treatment temperature of glass transformation temperature (Tg) of said glass powder.

According to the present invention; What can expect is; The glass that comprises in the insulating properties jointing material is bonded to each other etc. because of the heat treatment deformation in the manufacturing process of dust core or glass; Thus, can alleviate expansion and the contraction (can expect to improve the mechanical strength of insulating properties jointing material) that the thermal degradation when of binding resin causes.That is, what can expect is, glass is not only as the state of fillers dispersed in the insulating properties jointing material, and its performance prevents that in said insulating properties jointing material the binding resin layer from expanding or the effect of the wedge spare that shrinks.

At this, the permeability of dust core can be expressed by the numerical expression of the Ollendrof of the direct current permeability of the aggregate of expression ferromagnetism powder.

As the filling rate of soft magnetic powder is that effective counter field coefficient of η, soft magnetic powder is that the intrinsic permeability of N, soft magnetic powder is the function of μ t,

[formula 1]

${\mathrm{\μ}}_{\mathrm{dc}}=\frac{\mathrm{\η}\·{\mathrm{\μ}}_0\·({\mathrm{\μ}}_t-{\mathrm{\μ}}_0)}{N\·(1-\mathrm{\η})\·({\mathrm{\μ}}_t-{\mathrm{\μ}}_0)+{\mathrm{\μ}}_0}+{\mathrm{\μ}}_0$

Wherein, μ ₀ Permeability 4 π * 10 for vacuum ^-7Hm ^-1

What can expect is, for effective counter field coefficient N, being filled with under the state of soft magnetic powder through the shape of soft magnetic powder or the magnetic field interaction between soft magnetic powder, can make its N more independent than soft magnetic powder little.

As stated, in the present invention, hybrid glass in the insulating properties jointing material; At this moment; Through selecting to have the glass (through heating with the high temperature of glass transformation temperature) of the glass transformation temperature lower than the heat treatment temperature in the manufacturing process of dust core (Tg), glass becomes the expansion that prevents the binding resin layer or the wedge spare of contraction, thus; What can expect is; Even dust core is exposed under the environment for use of high temperature for a long time, the interval of soft magnetic powder also is difficult for changing, and effectively the variation of counter field coefficient N is little.Thus, can reduce the variation of initial magnetic permeability.

Through with upper type, with the thermal stability of comparing the initial magnetic permeability that can improve dust core in the past.

In the present invention, the content of preferred said glass is more than the 0.1 quality % and in the scope below the 0.60 quality % with respect to the quality of said soft magnetic powder.Thus, not only can obtain the initial magnetic permeability (initial stage) with the equal extent that (do not contain glass) in the past, can also improve the thermal stability of initial magnetic permeability.

In addition, in the present invention, preferred: said glass has P at least ₂O ₅, B ₂O ₃And BaO, P ₂O ₅Ratio of components a be 40～60mol%, B ₂O ₃Ratio of components b be 2～20mol%, the ratio of components c of BaO is 5～45mol%, the ratio of components d of SnO is 0～45mol%, Al ₂O ₃Ratio of components e be 0～15mol%, and satisfy the relation of a+b+c+d+e≤100mol%.After obtain said glass as glass 2 and glass 3 in the experiment stated, not only can obtain and the roughly equal initial magnetic permeability (initial stage) of example in the past of not adding glass, and can improve the thermal stability of initial magnetic permeability.

In addition, in the present invention, Al ₂O ₃Ratio of components e be preferably 2～15mol%.

In addition, in the present invention, preferred: Li ₂The ratio of components f of O is 0～1mol%, CeO ₂Ratio of components g be 0～10mol%, TiO ₂Ratio of components i be 0～1mol%, and satisfy the relation of a+b+c+d+e+f+g+h+i=100mol%.

In addition, in the present invention, the glass transformation temperature of said glass (Tg) is preferably in 280 ℃～470 ℃ the scope.In addition, the glass transformation temperature of said glass (Tg) is preferably more than 360 ℃ and less than 470 ℃.

In addition, in the present invention, the thermal coefficient of expansion of preferred said glass is 60～110 (* 10 ^-7/ ℃).The thermal coefficient of expansion of said glass is preferably 60～90 (* 10 ^-7/ ℃).

Form through adjustment glass as above-mentioned, control glass transformation temperature (Tg), and further control thermal coefficient of expansion, thus can effectively improve the thermal stability of initial magnetic permeability.

In addition, in the present invention, said insulating properties jointing material preferably contains said glass and the little magnetic particle of the said soft magnetic powder of size ratio.Thus, what can expect is, in the present invention, is present between soft magnetic powder through making magnetic particle, can reduce effective counter field coefficient N, and can improve initial magnetic permeability (initial stage).

In addition, through adding magnetic particle, can improve the thermal stability of iron loss.At this, the iron loss of dust core (core losses) be divided into usually with measure the proportional magnetic hysteresis loss of frequency and with square proportional eddy current losses of measuring frequency.What can expect is, iron loss becomes big because of increase of the increase of above-mentioned effective counter field coefficient N, magnetic hysteresis loss that residual stress causes that the insulating properties jointing material brings soft magnetic powder etc.Therefore; What can expect is, through as the present invention, in the insulating properties jointing material, adding magnetic particle, and the combining etc. of the magnetic particle that adds to the insulating properties jointing material and glass; Even under the environment for use that is exposed to high temperature for a long time; Also can obtain the high mechanical properties of insulating properties jointing material, and can effectively suppress the change of residual stress, can improve the thermal stability of initial magnetic permeability and iron loss.

In the present invention, the content of said magnetic particle is less than in 0 quality % and the scope below the 0.60 quality % with respect to the quality of said soft magnetic powder preferably.At this moment, said magnetic particle is an oxidate magnetic material, particularly is preferably the ferritic at least one side of NiZn ferrite and MnZn.Thus, not only can improve initial magnetic permeability (initial stage), but also can effectively improve the thermal stability of initial magnetic permeability and iron loss.

[invention effect]

According to dust core of the present invention and manufacturing approach thereof, can improve the thermal stability of initial magnetic permeability.

In addition; Through not only adding glass but also add the little magnetic particle of size ratio soft magnetic powder, can improve initial magnetic permeability (initial stage), in addition to the insulating properties jointing material; The thermal stability of initial magnetic permeability not only can be improved, and the thermal stability of iron loss can be improved.

Description of drawings

Fig. 1 is the stereogram of dust core (iron core).

Fig. 2 is the vertical view of coil-embedded dust magnetic core.

Fig. 3 is the local amplification view (sketch map) of the dust core of execution mode of the present invention.

Fig. 4 is that expression is added with the curve chart of interdependence of initial magnetic permeability (initial stage) and iron loss (initial stage) and glass addition of dust core that glass transformation temperature (Tg) is 280 ℃ a glass 1.

Fig. 5 is expression to being added with glass transformation temperature (Tg) is that to apply heating-up temperature be 180 ℃ and 250 ℃, heating time to be the rate of change (%) of initial magnetic permeability under 1000 hours the situation of heat resistant test, after the said heat resistant test and the curve chart of the interdependence of iron loss variable quantity (%) and glass addition for the dust core of 280 ℃ glass 1.

Fig. 6 is the curve chart of initial magnetic permeability (initial stage) and iron loss (initial stage) and the interdependence of glass addition of representing to be added with respectively the dust core of glass 2 and glass 3.

To be expression applied heating-up temperature to the dust core that is added with glass 2 and glass 3 respectively to Fig. 7 is 200 ℃ and 250 ℃, heating time to be the rate of change (%) of initial magnetic permeability under 1000 hours the situation of heat resistant test, after the said heat resistant test and the curve chart of the interdependence of glass addition.

To be expression applied heating-up temperature to the dust core that is added with glass 2 and glass 3 respectively to Fig. 8 is 200 ℃ and 250 ℃, heating time to be iron loss rate of change (%) under 1000 hours the situation of heat resistant test, after the said heat resistant test and the curve chart of the interdependence of glass addition.

Fig. 9 is the expression initial magnetic permeability (initial stage) that is added with the ferritic dust core of NiZn (but not adding glass) and the curve chart of the interdependence of iron loss (initial stage) and NiZn ferrite addition.

Figure 10 is expression, and to have applied heating-up temperature be 200 ℃ and 250 ℃, heating time to be rate of change (%) and the iron loss rate of change (%) of initial magnetic permeability under 1000 hours the situation of heat resistant test, after the said heat resistant test and the curve chart of the interdependence of NiZn ferrite addition to being added with the ferritic dust core of NiZn (but not adding glass).

Figure 11 is expression to the compound initial magnetic permeability (initial stage) that is added with glass 2 and glass 3 and the ferritic dust core of NiZn and iron loss (initial stage) curve chart with the interdependence of glass addition.

To be expression be added with glass 2 and glass 3 and the ferritic dust core of NiZn to have applied heating-up temperature be 200 ℃ and 250 ℃, heating time to be the rate of change (%) of initial magnetic permeability under 1000 hours the situation of heat resistant test, after the said heat resistant test and the curve chart of glass addition interdependence compound Figure 12.

To be expression be added with glass 2 and glass 3 and the ferritic dust core of NiZn to have applied heating-up temperature be 200 ℃ and 250 ℃, heating time to be iron loss rate of change (%) under 1000 hours the situation of heat resistant test, after the said heat resistant test and the curve chart of the interdependence of glass addition compound Figure 13.

Figure 14 is the curve chart of relation of thermal coefficient of expansion and the initial magnetic permeability (initial stage) of the expression glass transformation temperature that contains the glass in a plurality of dust cores of glass, glass.

Figure 15 is the curve chart of relation of thermal coefficient of expansion and the iron loss (initial stage) of the expression glass transformation temperature that contains the glass in a plurality of dust cores of glass, glass.

Figure 16 is that the glass transformation temperature with glass is transverse axis, is that the longitudinal axis representes that it is that 200 ℃, heating time are the curve chart of the rate of change (%) of initial magnetic permeability under 1000 hours the situation of heat resistant test, after the said heat resistant test that a plurality of dust cores that contain glass have been applied heating-up temperature with the thermal coefficient of expansion of glass.

Figure 17 is that the glass transformation temperature with glass is transverse axis, is that the longitudinal axis representes that it is that 200 ℃, heating time are the curve chart of iron loss rate of change (%) under 1000 hours the situation of heat resistant test, after the said heat resistant test that a plurality of dust cores that contain glass have been applied heating-up temperature with the thermal coefficient of expansion of glass.

[symbol description]

1,3 dust cores

2 coil-embedded dust magnetic cores

4 coils

5 soft magnetic powders

6 insulating properties jointing materials

7 emptying apertures

Embodiment

Fig. 1 is the stereogram of dust core (iron core), and Fig. 2 is the vertical view of coil-embedded dust magnetic core.Fig. 3 is the part amplification view (sketch map) of dust core.

Dust core 1 shown in Figure 1 is through carrying out compression molding and heat-treat obtaining to the mixture with soft magnetic powder and insulating properties jointing material.

Symbol 5 shown in Figure 3 is a soft magnetic powder, and symbol 6 is the insulating properties jointing material.As shown in Figure 3, insulating properties jointing material 6 surrounds the surface of soft magnetic powders 5, and is present between the soft magnetic powder 5 and keeps (supporting) a plurality of soft magnetic powders 5.

In addition, as shown in Figure 3, on insulating properties jointing material 6, be formed with emptying aperture 7 everywhere.Need to prove, in Fig. 3, not to all soft magnetic powders 5 and emptying aperture 7 diacritics.

Coil-embedded dust magnetic core 2 shown in Figure 2 constitutes the coil 4 that has dust core 3, covered by said dust core 3.Inside and Fig. 3 of dust core 3 likewise constitute.

The amorphous soft magnetic powder of soft magnetic powder 5 for for example utilizing water atomization to process.Said amorphous soft magnetic powder (Fe base metal glass alloy powder) for example composition formula by Fe _{100-a-b-c-x-y-z-t}Ni _aSn _bCr _cP _xC _yB _zSi _tExpression, 0at%≤a≤10at%, 0at%≤b≤3at%, 0at%≤c≤6at%, 6.8at%≤x≤10.8at%, 2.0at%≤y≤9.8at%, 0at%≤z≤8.0at%, 0at%≤t≤5.0at%.

The average crystallite particle diameter (D50) of soft magnetic powder 5 is about 10 μ m～70 μ m.At this; In this execution mode; Soft magnetic powder 5 is not limited to amorphous; But for using amorphous soft magnetic powder and for the dust core that press-powder is shaped with the insulating properties jointing material, the saturated flux density that it is bigger when having than using soft magnetic ferrite etc., so help miniaturization.

Insulating properties jointing material 6 shown in Figure 3 constitutes has binding resin and glass.

Binding resin is silicone resin, epoxy resin, phenolic resins, urea resin, melmac etc.

Especially, for binding resin, be fit to use silicone resin as thermally stable resins.

The quality of the soft magnetic powder 5 contained with respect to dust core is added the binding resin about 0.5～5.0 quality %.

In this execution mode, as stated, contain glass in the insulating properties jointing material 6.At this, what can expect is that glass is dispersed in the binding resin layer.

Glass together mixes with soft magnetic powder 5, binding resin etc. with Powdered at first; About the shape of Fig. 1, dust core 1,3 shown in Figure 2 being carried out the heat treatment after the compression molding; In this execution mode, this heat treatment is to carry out with the temperature higher than the glass transformation temperature (Tg) of glass.

Therefore, in this execution mode, what can expect is, glass for example from initial powdered products change shape or produce each other combination of glass, in resin the part diffusion, with the fusion of resin etc.

In this execution mode; Keep a plurality of soft magnetic powders 5 by the little binding resin layer of Young's modulus; And further glass transformation temperature (Tg) is put into insulating properties jointing material 6 than the low glass of heat treatment temperature that in the manufacturing process of dust core, carries out, thereby be configured to alleviate expansion and contraction that the thermal degradation when because of the binding resin layer causes.What can expect is, glass (powder) is exposed to than in the high heat treatment of glass transformation temperature (Tg), thereby produces distortion, glass combination each other etc., and thus, said glass plays the effect of the wedge spare of expansion that conduct prevents the binding resin layer, contraction.

As the decision dust core 1,3 permeability factor one of, have effective counter field coefficient N.About effective counter field coefficient N; What can expect is, as shown in Figure 3, under the state that is filled with a plurality of soft magnetic powders 5; Through approaching soft magnetic powder 5 mutual magnetic action each other etc., effectively counter field coefficient N becomes the effective counter field coefficient N little value more independent than soft magnetic powder 5.

Under the environment for use that is exposed to high temperature for a long time, if the variation at the interval of 5 of each soft magnetic powders is little, then effectively the variation of counter field coefficient N is also little.

As stated; In this execution mode; What can expect is, the glass with glass transformation temperature lower than the heat treatment temperature that in the manufacturing process of dust core, applies (Tg) can be alleviated expansion, the contraction that the thermal degradation when because of the binding resin layer causes, even under the environment for use that is exposed to high temperature for a long time; Also can make the variation at interval of 5,5 of soft magnetic powders in the dust core 1,3 littler, so can reduce the variation of effective counter field coefficient N than in the past.

Can know based on above content, according to this execution mode, with the thermal stability of comparing the initial magnetic permeability that can improve dust core 1,3 in the past.Therefore, can improve the thermal stability of inductance.

In this execution mode, the quality that the content of glass preferably falls into respect to soft magnetic powder 5 is in the scope that 0.1 quality % (wt%) is above and 0.60 quality % (wt%) is following.If the addition of glass is too much, what can expect is, the interval of 5,5 of the soft magnetic powders at (initial stage) becomes big during the formation of dust core, thereby effectively the value of counter field coefficient N itself also becomes greatly, and initial magnetic permeability reduces easily.

In this execution mode, through the addition of restriction glass as above-mentioned, can obtain the initial magnetic permeability (initial stage) with the equal extent that (do not contain glass) in the past, and can improve the thermal stability of initial magnetic permeability.At this, initial magnetic permeability (initial stage) is meant, initial magnetic permeability (initial stage), before being exposed under the high temperature environment for use when dust core forms.

In addition, glass constitutes and has P at least ₂O ₅, B ₂O ₃And BaO, and P ₂O ₅Ratio of components a be 40～60mol%, B ₂O ₃Ratio of components b be 2～20mol%, the ratio of components c of BaO is 5～45mol%, the ratio of components d of SnO is 0～45mol%, Al ₂O ₃Ratio of components e be 0～15mol%, preferably satisfy the relation of a+b+c+d+e≤100mol%.

For the compositing range of this glass; Through the glass in the experiment of stating after containing 2,3; And suitably control glass transformation temperature (Tg) according to this glass; Thereby can make initial magnetic permeability (initial stage) and the example in the past of not adding glass about equally, and can improve the thermal stability of initial magnetic permeability.

In addition; It is in the above and scope below the 0.60 quality % (wt%) of 0.1 quality % (wt%) that the content of the glass through making above-mentioned composition falls into quality with respect to soft magnetic powder 5; Thus; According to after the experiment stated, can realize the raising of the thermal stability of initial magnetic permeability, and can further make below iron loss (initial stage) (do not contain glass) in the past.

In addition, in this execution mode, Al ₂O ₃Ratio of components e be preferably 2～15mol%.In addition, P ₂O ₅Ratio of components a be preferably 41～55mol%.In addition, B ₂O ₃Ratio of components b be preferably 2～15mol%.In addition, the ratio of components c of BaO is preferably 5～30mol%.The ratio of components d of SnO is preferably 0～30mol%, more preferably 25～30mol%.In addition, Al ₂O ₃Ratio of components e 2～10mol more preferably.

Furthermore, in this execution mode, except above-mentioned, can also comprise Li ₂O, CeO ₂, TiO ₂In at least a kind.In this case, Li ₂The ratio of components f of O is 0～1mol%, CeO ₂Ratio of components g be 0～10mol%, TiO ₂Ratio of components i be 0～1mol%, preferably satisfy the relation of a+b+c+d+e+f+g+h+i=100mol%.

For the heat treatment of after the mixture compression molding that will have soft magnetic powder 5 and insulating properties jointing material 6, implementing, it is vital operation that this heat treatment obtains aspect the good magnetic characteristic in the distortion (askew body) of eliminating soft magnetic powder 5.Therefore, heat treated optimum temperature exists with ... soft magnetic powder 5, in this execution mode, and the glass of the glass transformation temperature (Tg) that (the best) heat treatment temperature that selection has than carries out in the manufacturing process of dust core is low.

The glass transformation temperature of the glass in this execution mode (Tg) is preferably about 280 ℃～470 ℃.In addition, glass transformation temperature (Tg) is preferably more than 360 ℃ and less than 470 ℃.In addition, glass transformation temperature (Tg) is more preferably more than 440 ℃ and less than 470 ℃.

Through having the glass of above-mentioned composition, glass transformation temperature (Tg) is fallen in the above-mentioned scope.

In addition, what can expect is under (heat treatment temperature-glass transformation temperature (Tg)) not too big situation, these both sides of thermal stability of high initial magnetic permeability are effectively improved.In addition, can also iron loss (core losses) setting at initial stage be become and not add below the routine in the past equal degree of glass.At this, " iron loss at initial stage " be meant, (initial stage) iron loss before being exposed under the environment for use of high temperature when dust core forms.

Particularly, (heat treatment temperature-glass transformation temperature (Tg)) is about 2～100 ℃, is preferably about 2～28 ℃.

Furthermore, what can expect is, preferably controls the thermalexpansioncoefficient of glass together with glass transformation temperature (Tg), can improve the thermal stability of initial magnetic permeability thus.As thermalexpansioncoefficient, be preferably 60～110 (* 10 ^-7/ ℃), more preferably 60～90 (* 10 ^-7/ ℃).

Furthermore, in this execution mode, preferably disperse the little magnetic particle of size ratio soft magnetic powder 5 to insulating properties jointing material 6.The particle diameter of magnetic particle is in the interval of 5,5 of soft magnetic powders shown in Figure 3, roughly not make the small particle diameter that just can roughly get into this degree under the condition of enlarged of said interval; Particularly, thus magnetic particle is a nano particle becomes the particle diameter enough littler than soft magnetic powder 5.For magnetic particle, can select the material different with soft magnetic powder 5.

For example, magnetic particle is preferably the oxidation Magnaglo, particularly is at least one side in NiZn ferrite or the MnZn ferrite.

So, what can expect is, not only contains glass in the insulating properties jointing material 6 but also contains magnetic particle through making, and can make said magnetic particle be present in soft magnetic powder 5, between 5, can reduce the value of effective counter field coefficient N itself.Thus, the initial magnetic permeability of dust core 1,3 is improved.

In addition, through adding magnetic particle, can improve the thermal stability of iron loss.As reducing one of factor of iron loss, can enumerate the situation that stress (residual stress) that the soft magnetic powder 5 of sening as an envoy to receives reduces.At this; What can expect is; Through in insulating properties jointing material 6, adding combining etc. of magnetic particle and magnetic particle and glass, not only can be directed against the environment for use that is exposed to high temperature for a long time improve the mechanical strength of insulating properties jointing material 6, and can effectively suppress the change with respect to the residual stress of soft magnetic powder 5; Thus, can improve the thermal stability of initial magnetic permeability and iron loss.

In this execution mode, the content of magnetic particle preferably falls into respect to the quality of soft magnetic powder 5 to greater than in 0 quality %, the scope below the 0.60 quality %.

Through as above-mentioned, the glass that in this execution mode, in insulating properties jointing material 6, adds and the addition of magnetic particle being adjusted, according to after the experiment stated, can effectively improve the thermal stability of initial magnetic permeability and iron loss.In addition, can initial magnetic permeability (initial stage) be set at in the past more than the equal degree of example (do not contain glass and also do not contain magnetic particle).The iron loss at initial stage still also is in the spendable scope than example (do not contain glass and also do not contain magnetic particle) was high slightly in the past.

Below, the manufacturing approach of the dust core of this execution mode is described.

At first, the soft magnetic powder, binding resin, glass powder, lubricant, the cement that utilize water atomization etc. to process are stirred, mix with solvent, thereby process the slip of mud shape.And can further mix magnetic particulates such as NiZn ferrite, MnZn ferrite.

At this,, can use the inferior lead of stearic acid, aluminum stearate etc. as lubricant.In addition, as cement, can use silane connecting agent etc.

Above-mentioned slip is put into existing prilling granulator, make the solvent wink-dry of slip, thereby generate through having the granular mixture of soft magnetic powder and insulating properties jointing material.

Next, said mixture is filled in the finishing die, thereby compression molding is the shape of dust core.Then, dust core is implemented heat treatment.The heat treatment of this moment is carried out under than the high temperature of the glass transformation temperature (Tg) of glass.At this moment; Owing to confirm best heat treatment temperature in advance for the distortion of eliminating soft magnetic powder; So heat treatment temperature is set at than the high temperature of glass transformation temperature (Tg), selects to have the glass of the glass transformation temperature lower (Tg) for this reason than heat treatment temperature.

What can expect is that through this heat treatment, lubricant roughly gasifies and disappears, thereby integrated with binding resin.The part of binding resin also gasifies and disappears.In this execution mode, glass and binding resin are together as the part of insulating properties jointing material 6 and be present between soft magnetic powder.Glass as above-mentioned the stage of processing slip as Powdered and sneak into; But after compression molding and heat treatment, glass is out of shape from Powdered the beginning; Perhaps glass becomes state that is bonded to each other etc.; Thereby what can expect is, glass is not merely simple filler, and it also has the effect of the wedge spare of the expansion that in the insulating properties jointing material, prevents the binding resin layer, contraction.

The dust core of this execution mode has the good initial magnetic permeability and the thermal stability of iron loss.Requirement such as the reactor that therefore, is particularly suitable for using in the loop of boosting, generating converting equipment at hybrid motor vehicle etc., transformer, choking-winding have the purposes of thermal stability under long hot environment.

[embodiment]

(obtaining the experiment of relation of characteristic and thermal stability of use level and the dust core of glass 1)

With the Fe that uses water atomization to process _74.43at%Cr _1.96at%P _9.04at%C _2.16at%B _7.54at%Si _4.87at%Be that inferior lead of amorphous soft magnetic powder, silicone resin, stearic acid and phosphoric acid glass powder (glass 1) mix and process mixture.The KF9079 powder that this phosphoric acid glass uses oxygen AGC TECNO GLASS to process.The glass transformation temperature of glass 1 (Tg) is 280 ℃.In addition; The use level of the silicone resin in the said mixture is 1.4wt% with respect to the quality of soft magnetic powder; The use level of the inferior lead of stearic acid is 0.3wt% with respect to the quality of soft magnetic powder, and the use level of glass powder is 0wt%, 0.3wt%, 0.6wt%, 1.2wt%, 2.4wt%, 4.2wt% and 6.1wt% with respect to the quality of soft magnetic powder.

Next, in mould, fill said mixture, under contact pressure 1470MPa, carry out press molding, thereby process the ring-type test portion of external diameter 20mm * internal diameter 12mm * thickness 6.8mm.The ring-type test portion that is obtained is carried out 1 hour heat treatment in stream of nitrogen gas atmosphere, thereby process dust core under 470 ℃.

Utilize Super Megohmmeter (DKK-TOA makes SM-8213) that the intrinsic resistance of the ring-type dust core that obtained is measured; Carry out the coiling of copper cash to the ring-type dust core; Use Impedance Analyzer (HP 4192A) to measure initial magnetic permeability, use BHAnalyzer (the rugged communication system of rock) under the condition of frequency 100kHz, Bm=100mT, to measure iron loss (initial stage).In heat resistant test, the ring-type dust core put into 180 ℃, 250 ℃ drying oven and keep 1000 hours in atmosphere after, initial magnetic permeability and iron loss have been measured.Each measures the result shown in the table 1.

[table 1]

Fig. 4 is the curve chart of relation of addition and initial magnetic permeability (initial stage) and iron loss (initial stage) of the glass 1 of each dust core shown in the expression table 1.Know that according to table 1 and shown in Figure 4 along with the increase of the addition of glass 1, initial magnetic permeability reduces, on the other hand, iron loss increases to some extent.If the glass addition surpasses 0.6wt%, then initial magnetic permeability descends more than 10% with respect to the No.1 that does not add glass (example in the past), and on the other hand, iron loss increases more than 40%.Hence one can see that, and the reduction for the magnetic characteristic that prevents dust core need make the glass addition become below the 0.6wt%.

Can know also that in addition the intrinsic resistance of the dust core shown in the table 1 shows the tendency of increase along with the increase of the addition of glass 1, because any test portion is 10 ⁶More than the Ω cm, thereby has sufficiently high value as dust core.

Fig. 5 is that to implement heating-up temperature be 180 ℃ and 250 ℃, heating time to be the curve chart of relation of rate of change (%) and the iron loss variable quantity (%) of addition under 1000 hours the situation of heat resistant test, glass 1 and the initial magnetic permeability after the said heat resistant test to each dust core of expression his-and-hers watches 1.At this, " rate of change of initial magnetic permeability " represented by [initial magnetic permeability at (initial magnetic permeability at the initial magnetic permeability-initial stage after the heat resistant test)/initial stage] * 100 (%)." initial magnetic permeability at initial stage " during for the formation of dust core (initial stage) and be exposed under the high temperature environment for use before initial magnetic permeability.

In addition, " iron loss rate of change " represented by [iron loss at (iron loss at the iron loss-initial stage after the heat resistant test)/initial stage] * 100 (%)." iron loss at initial stage " is meant, when dust core forms (initial stage) and be exposed under the environment for use of high temperature before iron loss.

As the target of thermal stability, for the rate of change of initial magnetic permeability, setting for is being in ± 15% after 180～200 ℃ * 1000 hours; Be preferably ± 10% in, after 250 ℃ * 1000 hours, be in ± 25%, be preferably ± 20% in; In addition, for the iron loss rate of change, setting for is being in ± 40% after 180～200 ℃ * 1000 hours; Be preferably ± 30% in, after 250 ℃ * 1000 hours, be in ± 70%, be preferably ± 50%.

Know that according to table 1 and shown in Figure 5 along with the increase of the addition of glass 1, the rate of change of the initial magnetic permeability after the heat resistant test (%) is though be negative value, it has the tendency that reduces as absolute value.Can know that in addition iron loss rate of change (%) also has the tendency that reduces.If the addition of glass 1 is more than the 1.2wt%; Can satisfy the target of above-mentioned heat-resistant stability more effectively, still, like table 1 and shown in Figure 4; Can know and have following problem; That is, the addition of glass is more than the 1.2wt%, causes the low and iron loss (initial stage) of initial magnetic permeability (initial stage) to become big thus.

Can know on the other hand; If the addition of glass 1 is below the 0.6wt%; Though surpassing the rate of change of the initial magnetic permeability after-20%, 180 ℃ * 1000 hours slightly, the rate of change of the initial magnetic permeability after then 250 ℃ * 1000 hours keeps-2%～-3% so lower value.Can know that in addition for iron loss, if the addition of glass 1 is below the 0.6wt%, the iron loss rate of change after then 180 ℃ * 1000 hours can be kept in 30%.

(manufacturing of glass 2,3)

Glass 2,3 generates through following manufacturing approach.

Frit uses the plain powder of former phosphoric acid, boron oxide, barium carbonate powder, stannic oxide powder, the alumina powder of selling on the market.These raw materials are measured and make its use level that becomes regulation, put into platinum crucible then and be pre-mixed, use electric furnace in air atmosphere, to dissolve subsequently.The design temperature of electric furnace is set at 1000～1300 ℃.

Then, take out platinum crucible, glass is dissolved body in the cast iron casting mould, cast and obtain glass from electric furnace.Obtain glass powder this glass being used ball mill pulverize after the coarse crushing in mortar.

In addition; Cut out the glass blocks of 3mm * 3mm * 20mm from the part of glass of casting; Eliminate the annealing in process of distortion then, use hot device analysis device (motor system TMA8310 of science) to measure glass transformation temperature, yield temperature and thermal coefficient of expansion subsequently.The use level of each glass 2,3 of processing and glass transformation temperature, yield temperature and thermal coefficient of expansion are shown in the table 2.

[table 2]

(obtaining the experiment of relation of characteristic and thermal stability of use level and the dust core of glass 2,3)

With the Fe that uses water atomization to process _77at%Cr _1at%P _9.23at%C _2.2at%B _7.7at%Si _2.87at%Be that the inferior lead of amorphous soft magnetic alloy powder, silicone resin, stearic acid and pulverous glass 2 or pulverous glass 3 mix and process mixture.

At this, as shown in table 2, the glass transformation temperature (Tg) of glass 2 (phosphoric acid glass) is 468 ℃, than low 2 ℃ of the heat treatment temperature of in the manufacturing process of dust core, implementing (470 ℃).In addition, the glass transformation temperature of glass 3 (phosphoric acid glass) is 442 ℃, than low 28 ℃ of the heat treatment temperature of in the manufacturing process of dust core, implementing (470 ℃).

In addition; The use level of the silicone resin in the mixture is 2.0wt% with respect to the quality of soft magnetic powder; The use level of the inferior lead of stearic acid is 0.3wt% with respect to the quality of soft magnetic powder, and the use level of each glass 2,3 is 0wt%, 0.1wt%, 0.3wt%, 0.6wt% with respect to the quality of soft magnetic powder.

Next, said mixture is filled in the mould, carries out press molding, thereby process the ring-type test portion of external diameter 20mm * internal diameter 12mm * thickness 6.8mm with contact pressure 1470MPa.The ring-type test portion that is obtained is carried out 1 hour heat treatment in stream of nitrogen gas atmosphere, thereby process dust core under 470 ℃.

A quality and a profile cun method according to the ring-type dust core that is obtained are calculated the density of magnetic core, and the numerical computations of use use level goes out the occupation rate of soft magnetic powder.The calculating formula of the occupation rate of soft magnetic powder is as follows.

[formula 2]

Next; Use Super Megohmmeter (SM-8213 of DKK-TOA system) to measure the intrinsic resistance of ring-type dust core; Twine copper cash to the ring-type dust core; Use ImpedanceAnalyzer (HP 4192A) to measure initial magnetic permeability, use BHAnalyzer (the rugged communication system of rock) under the condition of frequency 100kHz, Bm=100mT, to measure iron loss.In heat resistant test, the ring-type dust core is put in atmosphere after 200 ℃, 250 ℃ drying oven kept 1000 hours, measure initial magnetic permeability and iron loss.Each measures the result shown in the table 3.

[table 3]

Need to prove that glass 2 is used in the dust core No.9 shown in the table 3～11, glass 3 is used in dust core No.12～14.Dust core No.8 is not for adding the example in the past of glass.

Fig. 6 representes to be added with respectively the curve chart of initial magnetic permeability (initial stage) and iron loss (initial stage) and the relation of the addition of glass 2,3 that the glass transformation temperature shown in the table 3 (Tg) is each dust core of 468 ℃ glass 2 and glass transformation temperature (Tg) glass 3 that is 442 ℃.Hence one can see that; No matter under the situation of using which kind of glass; All there is the tendency that reduces slightly in initial magnetic permeability along with the increase of glass addition, and the initial magnetic permeability when the glass addition is 0.6wt% descends about 2～4% with respect to the No.8 that does not add glass (example in the past).

In addition, know that iron loss (initial stage) is under the situation of using glass 2 according to table 3 and shown in Figure 6; Along with the increase of the addition of glass 2 and demonstrate the tendency of minimizing; On the other hand, close using under the situation of glass 3, the almost fixed value is shown with respect to the increase of the addition of glass 3.

Can know than the glass 2,3 of low 2～28 ℃ of the heat treatment temperature in the manufacturing process of dust core through using glass transformation temperature (Tg); If add the glass 2,3 of 0.1wt%～0.6wt%; Then the initial magnetic permeability of dust core and the situation of not adding glass are in a ratio of and equate or low slightly, iron loss with do not add situation that glass adds and be in a ratio of and equate and raising (can reduce) arranged slightly.

Intrinsic resistance shown in the table 3 is little with respect to its variation of increase of the addition of glass 2,3, and test portion all is 10 arbitrarily ⁶More than the Ω cm, hence one can see that, has sufficiently high value as dust core.In addition, the occupation rate that occupies the amorphous soft magnetic powder of dust core is 78～80%.

Fig. 7 is that the glass transformation temperature (Tg) of representing to be added with respectively table 3 is behind 200 ℃ * 1000 hours of each dust core of 468 ℃ glass 2 and glass transformation temperature (Tg) glass 3 that is 442 ℃ and the curve chart of the relation of the rate of change (%) of glass 2,3 additions after 250 ℃ * 1000 hours and initial magnetic permeability.The initial magnetic permeability that is added with behind 200 ℃ * 1000 hours of dust core of glass 2 is reduced to when the addition of glass 2 reaches 0.3wt% about-11%, and still, if the addition of glass 2 is 0.6wt%, then the rate of change of initial magnetic permeability is-4%.How the addition that is added with the rate of change glass 2 of the initial magnetic permeability behind 250 ℃ * 1000 hours of dust core of glass 2 all is depicted as almost fixed value promptly about-13%.

On the other hand; The rate of change of initial magnetic permeability that is added with the dust core of glass 3 reduces along with the increase of glass addition; If add the glass 3 of 0.6wt%, then the rate of change of initial magnetic permeability was-2% after 200 ℃ * 1000 hours, after 250 ℃ * 1000 hours, was-8%.

Fig. 8 is that the glass transformation temperature (Tg) of representing to be added with respectively table 3 is behind 200 ℃ * 1000 hours of each dust core of 468 ℃ glass 2 and glass transformation temperature (Tg) glass 3 that is 442 ℃ and the curve chart of the relation of the addition of the glass 2,3 after 250 ℃ * 1000 hours and iron loss rate of change (%).

Like table 3 and shown in Figure 8; Be added with behind 200 ℃ * 1000 hours of dust core of glass 2 and the iron loss rate of change after 250 ℃ * 1000 hours along with the increase of the addition of glass 2 same increasing; If add the glass 2 of 0.6wt%, then the iron loss rate of change be respectively+80% ,+138%.On the other hand, be added with behind 200 ℃ * 1000 hours of dust core of glass 3 and the iron loss rate of change after 250 ℃ * 1000 hours little with respect to its variation of increase of the addition of glass 3, be respectively+44% ,+58%.

Can know in view of the above, be 0.1～0.6wt% through the addition that makes glass 2,3, can initial magnetic permeability (initial stage) be set for and the equal degree of situation (No.8) of not adding glass, and, can improve the thermal stability (heat-resistant quality) of initial magnetic permeability.In addition, iron loss (initial stage) become with example (No.8) in the past about equally or be reduced to below it.

Glass 1 and glass 2,3 are compared; The glass transformation temperature of glass 1 (Tg) is 280 ℃; Than low about 200 ℃ of the heat treatment temperature of in the manufacturing process of dust core, implementing (470 ℃); But the glass transformation temperature (Tg) of glass 2,3 is only than low 2～28 ℃ of the heat treatment temperature of in the manufacturing process of dust core, implementing (470 ℃).

Can know in addition, be used at glass 1 under the situation of dust core, though the rate of change of the initial magnetic permeability after 180 ℃ * 1000 hours is suppressed lowly, the tendency that exists the beginning permeability to decline to a great extent easily.On the other hand; Be used under the situation of dust core at glass 2,3; Initial magnetic permeability (initial stage) can become and the equal degree of situation of not adding glass, and after not only 180 ℃ * 1000 hours, and the rate of change of initial magnetic permeability also is suppressed lowly after 250 ℃ * 1000 hours.

Can know that in addition as the glass that is used for dust core, glass 2,3 is compared the thermal stability with higher initial magnetic permeability with glass 1, therefore more preferred on the one hand at this.

(the compound experiment that is added with glass and magnetic particle)

Make the Fe of system with using water atomization _77at%Cr _1at%P _9.23at%C _2.2at%B _7.7at%Si _2.87at%Be that inferior lead of amorphous soft magnetic alloy powder, silicone resin, stearic acid and NiZn ferrite powder (magnetic particle) mix and process mixture.This NiZn ferrite powder uses Kawasaki Steel system KN1-106GMS, brings into use utilizing ball mill to carry out drying after carrying out pulverizing in 30 hours.

And then, with the Fe that uses water atomization to process _77at%Cr _1at%P _9.23at%C _2.2at%B _7.7at%Si _2.87at%Be that inferior plumbous, NiZn ferrite powder of amorphous soft magnetic alloy powder, silicone resin, stearic acid and glass 2 or glass 3 mix respectively and processes mixture.In addition; The use level of the silicone resin in this mixture is 2.0wt% with respect to the quality of soft magnetic powder; The use level of the inferior lead of stearic acid is 0.3wt% with respect to the quality of soft magnetic powder; The use level of NiZn ferrite powder with respect to the quality of soft magnetic powder be 0.3,0.6,1.2wt%, the use level of glass 2,3 with respect to the quality of soft magnetic powder be respectively 0,0.1,0.3,0.6wt%.

Next, this mixture is filled in the mould, carries out press molding, thereby process the ring-type test portion of external diameter 20mm * internal diameter 12mm * thickness 6.8mm with contact pressure 1470MPa.With the ring-type test portion that is obtained in nitrogen current atmosphere with 470 ℃ of heat treatments of carrying out 1 hour, thereby process dust core.

A quality and a profile cun method according to the ring-type dust core that is obtained are calculated the density of magnetic core, and the numerical computations of use use level goes out the occupation rate (with reference to numerical expression 2) of amorphous soft magnetic alloy powder.In addition; Use Super Megohmmeter (DKK-TOA makes SM-8213) to measure the intrinsic resistance of ring-type dust core; Twine copper cash to the ring-type dust core; Use ImpedanceAnalyzer (HP 4192A) to measure initial magnetic permeability, use BHAnalyzer (the rugged communication system of rock) under the condition of frequency 100kHz, Bm=100mT, to measure iron loss.Heat resistant test is measured as follows, and the ring-type dust core is put into 200 ℃, 250 ℃ drying oven in atmosphere, measures the initial magnetic permeability and the iron loss that keep after 1000 hours.Each measures the result shown in the table 4.

[table 4]

Fig. 9 is the curve chart of the relation of the ferritic addition of NiZn and initial magnetic permeability (initial stage) and iron loss (initial stage) in expression dust core No.15～18 (are added with the NiZn ferrite, do not add glass).Dust core No.15 is the example in the past that does not contain glass and these both sides of NiZn ferrite.

Can know that in addition along with the increase of the ferritic addition of NiZn, initial magnetic permeability of dust core (initial stage) and iron loss (initial stage) all increase to some extent.

Figure 10 is the curve chart of relation of rate of change and the iron loss rate of change of NiZn ferritic addition and the initial magnetic permeability of expression dust core No.15～18 (are added with the NiZn ferrite, are not added with glass) when being exposed in the heat resistant test of 200 ℃ and 250 ℃ * 1000 hours.Increase along with the ferritic addition of NiZn; The rate of change of initial magnetic permeability is a negative value; Its absolute value becomes greatly gradually, if the ferritic addition of NiZn is 1.2wt%, then after 200 ℃ * 1000 hours, be respectively-12% ,-18% after 250 ℃ * 1000 hours.The iron loss rate of change is dull the minimizing in 200 ℃ heat resistant test; In 250 ℃ heat resistant test; The ferritic addition of NiZn is 0.3wt% and after maximum is shown, begins to reduce, if the ferritic addition of NiZn is 1.2wt%, it is shown as+6% ,+34%.

Figure 11 is the curve chart of relation of initial magnetic permeability (initial stage) and iron loss (initial stage) of addition and dust core of the glass 2,3 of expression dust core No.19～24 (being added with NiZn ferrite, glass 2,3).Be added with glass 2 in dust core No.19～21, in dust core No.21～24, be added with glass 3.Need to prove that as shown in table 4, in dust core No.19～24, the ferritic addition of NiZn is unified to be 0.6wt%.

Initial magnetic permeability (initial stage) when in addition, the addition of the glass 2,3 of Figure 11 is 0wt% and iron loss (initial stage) have the value that the NiZn ferrite is the dust core No.17 of 0.6wt%.

According to knowing shown in Figure 11 and the table 4; Initial magnetic permeability demonstrates the tendency that minimizing is arranged slightly along with the increase of the addition of glass 2,3; But; If the addition of glass 2,3 is 0.1wt%, then compare with the dust core No.15 that does not add glass and these both sides of NiZn ferrite (example in the past), can improve initial magnetic permeability.

On the other hand; The addition of the not interdependent glass 2,3 of iron loss (initial stage) and be depicted as the almost fixed value, but through adding glass 2, with respect to dust core No.17 (the glass addition is 0wt%); Iron loss (initial stage) has the tendency that reduces slightly; Through adding glass 3,, has the tendency that iron loss (initial stage) increases with respect to dust core No.17 (the glass addition is 0wt%).

The curve chart of the relation of the rate of change of glass addition and the initial magnetic permeability of Figure 12 when to be expression to dust core No.19～24 (being added with NiZn ferrite and glass 2,3) carry out the heat resistant test of 200 ℃ * 1000 hours and 250 ℃ * 1000 hours.

Need to prove that the rate of change of the initial magnetic permeability the when addition of the glass 2,3 of Figure 12 is 0wt% becomes the value that the NiZn ferrite is the dust core No.17 of 0.6wt%.

According to knowing shown in Figure 12 and the table 4, the rate of change of the initial magnetic permeability after 200 ℃ * 1000 hours is a negative value, but along with its absolute value of increase of the addition of glass 2 reduces gradually.But under the situation that is added with glass 3, if addition is 0.3～0.6wt%, then the rate of change of initial magnetic permeability does not roughly change for-3%.

Next, according to knowing shown in Figure 12 and the table 4, the rate of change of the initial magnetic permeability after 250 ℃ * 1000 hours is a negative value, but under the situation that is added with glass 2, along with the increase of glass addition, the rate of change of initial magnetic permeability (absolute value) reduces gradually.On the other hand, though the rate of change of the initial magnetic permeability when being added with glass 3 also is negative value, the rate of change of initial magnetic permeability (absolute value) is compared to some extent with the situation of not adding glass (dust core No.17) and is reduced.But, for the rate of change of the initial magnetic permeability when being added with glass 3, even the glass addition changes, the also roughly not change of rate of change of the initial magnetic permeability of this moment.

The curve chart of the relation of glass addition and the iron loss rate of change of Figure 13 when to be expression to dust core No.19～24 (being added with NiZn ferrite, glass 2,3) applied the heat resistant test of 200 ℃ and 250 ℃ * 1000 hours.

Need to prove that the iron loss rate of change the when addition of the glass 2,3 of Figure 13 is 0wt% has the value that the NiZn ferrite is the dust core No.17 of 0.6wt%.

It is roughly the same tendency when being 200 ℃ and 250 ℃ that the iron loss rate of change is expressed in the heat resistant test temperature.Under the situation that is added with glass 2, even being increased to 0.3wt%, addition also expresses roughly the same iron loss rate of change, if addition is increased to 0.6wt%, then the iron loss rate of change becomes big.

Can know that on the other hand under the situation that is added with glass 3, when addition was 0.1wt%, the iron loss rate of change became minimum, if further increase addition, then the iron loss rate of change becomes big.

Know to shown in Figure 13 according to table 4 and Figure 11; Through compound interpolation glass and NiZn ferrite, can guarantee than higher initial magnetic permeability (initial stage), and can improve the thermal stability of initial magnetic permeability; But also can reduce the iron loss rate of change, improve the thermal stability of iron loss.Especially for being added with the dust core that glass transformation temperature (Tg) is 442 ℃ a glass 3 (especially dust core No.22), the iron loss rate of change being effectively reduced, thereby further improve the thermal stability of iron loss.

As stated; In the present embodiment; The quality that is set at respect to soft magnetic powder at the addition with glass is more than the 0.1 quality %, below the 0.6 quality %; And further add under the situation of magnetic particle, the quality that the addition of magnetic particle is set for respect to soft magnetic powder is greater than 0 quality % and is below the 0.6 quality %.

(through add forming the characteristic test of each dust core that each different glass forms)

Process and possess a plurality of glass that following glass is formed.

[table 5]

In each glass 4～18 of table 5, metering raw material and make its use level that becomes the regulation shown in the table 5 puts it into platinum crucible and is pre-mixed, and uses electric furnace in air atmosphere, it to be dissolved then.The design temperature of electric furnace is 1000～1300 ℃.

Next, take out platinum crucible, glass is dissolved body in the cast iron casting mould, cast and obtain glass from electric furnace.After utilizing mortar, use ball mill to pulverize and obtain glass powder this glass coarse crushing.

In addition; The part of the glass that obtains from casting cuts out the glass blocks of 3mm * 3mm * 20mm; Eliminate the annealing in process of distortion, use hot device analysis device (motor system TMA8310 of science) to measure glass transformation temperature, glass transition temperature (yield temperature) and thermal coefficient of expansion then.The use level of each glass 4～18 of processing and glass transformation temperature, glass transition temperature (yield temperature) and thermal coefficient of expansion are shown in the table 5.

In addition, also additional in table 5 have proportion and a vitrification point.

Then, mixture is processed in mixing such as each glass shown in the table 5, amorphous soft magnetic alloy powder, silicone resin and the inferior lead of stearic acid.The Fe of employed amorphous soft magnetic alloy powder for processing through water atomization _77at%Cr _1at%P _9.23at%C _2.2at%B _7.7at%Si _2.87at%It is amorphous soft magnetic alloy powder.

In addition; The use level of the silicone resin in this mixture is 2.0wt% with respect to the quality of soft magnetic powder; The use level of the inferior lead of stearic acid is 0.3wt% with respect to the quality of soft magnetic powder, and the use level of each glass is 0.6wt% with respect to the quality of soft magnetic powder.

Next, this mixture is filled in the mould, under contact pressure 1470MPa, carries out press molding, thereby process the ring-type test portion of external diameter 20mm * internal diameter 12mm * thickness 6.8mm.The ring-type test portion that is obtained is carried out heat treatment in 1 hour and processes dust core in nitrogen current atmosphere, under 470 ℃.

In experiment, carry out the coiling of copper cash to the ring-type dust core, use ImpedanceAnalyzer (HP 4192A) to measure initial magnetic permeability, use BHAnalyzer (the rugged communication system of rock) under the condition of frequency 100kHz, Bm=100mT, to measure iron loss.In heat resistant test, the ring-type dust core is put into the drying oven of 200 ℃ or 250 ℃ in atmosphere, measure the initial magnetic permeability and the iron loss that keep after 1000 hours.In addition, the compression stress when dust core effect compression stress also will make it damage is as maximum intensity unshakable in one's determination.Each measures the result shown in the table 6.

[table 6]

The hurdle of the glass shown in the table 6 is corresponding with the glass No of table 5.Need to prove that in table 6, the value of " μ ' (100kHz) " in 200 ℃, 250 ℃ the hurdle, " iron loss (100kHz, 100mT) " is an initial value.Though the value of the initial value separately of identical dust core No is slightly different; Use other dust cores under identical condition, process to measure but this is, carried out instrumentation at 200 ℃, 250 ℃ the rate of change that keeps each value after 1000 hours at each temperature respectively using each dust core.

Figure 14 is the curve chart of the initial magnetic permeability (initial stage) of each dust core shown in 200 ℃ the hurdle of expression table 6.In Figure 14, the glass transformation temperature Tg of the glass that adds to each dust core is a transverse axis, and the thermalexpansioncoefficient of glass is the longitudinal axis.Therefore, do not comprise the experimental result of the dust core of example in the past of not adding glass among Figure 14.

In addition, Figure 15 is the curve chart of the iron loss (initial stage) of each dust core shown in 200 ℃ the hurdle of table 6.In Figure 15, the glass transformation temperature Tg of the glass that adds to each dust core is a transverse axis, and the thermalexpansioncoefficient of glass is the longitudinal axis.Therefore, in Figure 15, do not comprise the experimental result of the dust core of example in the past of not adding glass.

In addition, Figure 16 is the rate of change (200 ℃, 1000 hours) of the initial magnetic permeability of each dust core shown in the table 6, and Figure 17 is expression and the curve chart of the relation of the iron loss rate of change (200 ℃, 1000 hours) of each dust core.In Figure 16, Figure 17, the glass transformation temperature Tg of the glass that adds to each dust core is a transverse axis, and the thermalexpansioncoefficient of glass is the longitudinal axis.Therefore, do not comprise the experimental result of the dust core of example in the past of not adding glass among Figure 16, Figure 17.

At first, because the heat treatment temperature during with each dust core compression molding of table 6 is 470 ℃, all be comparative example so be added with the dust core that has than the glass of 470 ℃ of high glass transformation temperatures (Tg).

In Figure 14 to Figure 17, the line (part) of 470 ℃ glass transformation temperatures (Tg) has been pulled out line.The right side of this line is a comparative example.

Experimental result through observation table 6, Figure 14 and Figure 16 can be known; Glass transformation temperature (Tg) through making glass is lower than 470 ℃; Can obtain than higher initial magnetic permeability (initial stage), and, with in the past the example (glass does not have interpolation) compare the rate of change (absolute value) that can effectively reduce initial magnetic permeability.So can know, can effectively improve the thermal stability of initial magnetic permeability according to present embodiment.In addition, the glass transformation temperature of glass (Tg) is preferably more than 360 ℃.

In addition, the thermalexpansioncoefficient (* 10 of glass ^-7/ ℃) be preferably 60～110, perhaps be about 60～90.Hence one can see that, can more effectively reduce the absolute value of the rate of change of initial magnetic permeability, can realize the raising of thermal stability.

Can know that in the present embodiment it is in 4% that the rate of change (absolute value) of the initial magnetic permeability after 200 ℃, 1000 hours can be suppressed, be preferably in 3%, more preferably in 2%, further be preferably in 1.5%.

Can know in addition,, become more than 360 ℃ and, can improve thermal stability less than 470 ℃ value through the glass transformation temperature (Tg) that makes glass for iron loss.

Claims (14)

1. dust core, its mixture compression molding and heat-treating through will having soft magnetic powder and insulating properties jointing material obtains, it is characterized in that,

Said insulating properties jointing material has binding resin and glass,

The glass transformation temperature of said glass (Tg) is lower than said heat treated temperature.

2. dust core according to claim 1 is characterized in that,

The content of said glass is in the scope more than the 0.1 quality %, below the 0.60 quality % with respect to the quality of said soft magnetic powder.

3. dust core according to claim 2 is characterized in that,

Said glass has P at least ₂O ₅, B ₂O ₃And BaO, P ₂O ₅Ratio of components a be 40～60mol%, B ₂O ₃Ratio of components b be 2～20mol%, the ratio of components c of BaO is 5～45mol%, the ratio of components d of SnO is 0～45mol%, Al ₂O ₃Ratio of components e be 0～15mol%, and satisfy the relation of a+b+c+d+e≤100mol%.

4. dust core according to claim 3 is characterized in that,

Al ₂O ₃Ratio of components e be 2～15mol%.

5. according to claim 3 or 4 described dust cores, it is characterized in that,

Li ₂The ratio of components f of O is 0～1mol%, CeO ₂Ratio of components g be 0～10mol%, TiO ₂Ratio of components i be 0～1mol%, and satisfy the relation of a+b+c+d+e+f+g+h+i=100mol%.

6. according to claim 3 or 4 described dust cores, it is characterized in that,

The glass transformation temperature of said glass (Tg) is in 280 ℃～470 ℃ scope.

7. dust core according to claim 3 is characterized in that,

The glass transformation temperature of said glass (Tg) is more than 360 ℃ and in less than 470 ℃ scope.

8. dust core according to claim 3 is characterized in that,

The thermal coefficient of expansion of said glass is 60～110 * 10 ^-7/ ℃.

9. dust core according to claim 3 is characterized in that,

The thermal coefficient of expansion of said glass is 60～90 * 10 ^-7/ ℃.

10. dust core according to claim 1 is characterized in that,

Except said glass, also contain the little magnetic particle of the said soft magnetic powder of size ratio in the said insulating properties jointing material.

11. dust core according to claim 10 is characterized in that,

The content of said magnetic particle is greater than in 0 quality %, the scope below the 0.60 quality % with respect to the quality of said soft magnetic powder.

12. dust core according to claim 10 is characterized in that,

Said magnetic particle is an oxidate magnetic material.

13. dust core according to claim 10 is characterized in that,

Said oxidate magnetic material is at least one side in NiZn ferrite and the MnZn ferrite.

14. the manufacturing approach of a dust core is characterized in that, comprising:

With soft magnetic powder, mix and generate the operation of mixture as the binding resin of insulating properties jointing material and glass powder;

With said mixture compression molding, the operation to heat-treat then than the high heat treatment temperature of glass transformation temperature (Tg) of said glass powder.

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