CN110178191A

CN110178191A - MnCoZn based ferrite and its manufacturing method

Info

Publication number: CN110178191A
Application number: CN201880003391.9A
Authority: CN
Inventors: 吉田裕史; 中村由纪子
Original assignee: JFE Chemical Corp
Current assignee: JFE Chemical Corp
Priority date: 2017-12-20
Filing date: 2018-05-21
Publication date: 2019-08-27
Anticipated expiration: 2038-05-21
Also published as: JP6742440B2; JPWO2019123681A1; CN110178191B; TW201927701A; TWI667200B; WO2019123681A1

Abstract

The present invention provides a kind of MnCoZn ferrite as basis and contains iron: with Fe₂O₃Conversion meter 45.0 moles of % more than and less than 50.0 moles %, zinc: 15.5~24.0 moles of %, cobalts in terms of ZnO conversion: 0.5~4.0 mole of % and manganese in terms of CoO conversion: surplus contains SiO as accessory ingredient relative to above-mentioned basis₂: 50~300 mass mass of ppm and CaO:300~1300 ppm, surplus is made of inevitable impurity, wherein, Cd, Pb, Sb, As and Se amount in above-mentioned inevitable impurity is suppressed to respectively less than 20 mass ppm, furthermore, make wearing valve less than 0.85%, make coercivity 15A/m or less at 23 DEG C, making 30 Ω m of resistivity or more and make 100 DEG C of Curie temperature or more, thus, not only there is high resistance, low-coercivity magnetic characteristic good in this way, but also have both excellent mechanical strength.

Description

MnCoZn based ferrite and its manufacturing method

Technical field

The present invention relates to resistivity height, coercivity is small and is not easy the MnCoZn based ferrite and its manufacturing method of defect.

It should be noted that in the present specification, coercivity refers to the value at 23 DEG C.

Background technique

As the typical example of soft magnetism oxidate magnetic material, MnZn ferrite can be enumerated.Existing MnZn ferrite The Fe with positive magnetic anisotropy containing about 2 mass % or more²⁺, by with the Fe with negative magnetic anisotropy³⁺、Mn²⁺It offsets Disappear, high initial permeability, low-loss are thus realized in the region kHz.

The MnZn ferrite is cheap compared with amorphous metal etc., therefore, noise filter, change as Switching Power Supply etc. Depressor, antenna magnetic core and be widely used.

But the ferritic Fe of MnZn²⁺Amount is more, therefore, has and is easy to happen Fe³⁺-Fe²⁺Between the giving and accepting of electronics, resistance Rate is down to m grades of such disadvantages of 0.1 Ω.Therefore, when used frequency field increases, the vortex flowed through in ferrite is drawn The loss risen sharply increases, and initial permeability is greatly reduced, and loss also increases.Therefore, the ferritic durable frequency of MnZn is with about Several hundred kHz are the limit, mainly use NiZn ferrite at MHz grades.The ferritic resistivity of the NiZn is 10⁵More than (Ω m), It is ferritic about 10,000 times of MnZn, eddy-current loss is few, therefore, is not easy to lose high initial permeability, low even if high-frequency region Such characteristic is lost.

But there are a big problems for NiZn ferrite.The problem is that soft magnetic material requires anti-to the variation of external magnetic field Sensitivity is answered, therefore, coercivity H is preferably smaller, and still, NiZn ferrite is only made of the ion with negative magnetic anisotropy, because This, the coercitive value is big.It should be noted that being provided in JIS C 2560-2 about coercivity.

As the big ferritic method of resistivity is obtained other than NiZn ferrite, there are by reducing MnZn iron Fe contained in oxysome²⁺It measures and makes the raised method of resistivity.

For example, reporting in patent document 1, patent document 2 and patent document 3 etc. by making Fe₂O₃Ingredient is less than 50 Mole %, Fe is reduced²⁺Content and the MnZn ferrite for improving resistivity.But they also it is same as NiZn ferrite only by Ion with negative magnetic anisotropy is constituted, therefore absolutely not solution coercivity reduces such problems.

Therefore, addition Fe is disclosed in patent document 4, patent document 5 and patent document 6²⁺In addition have positive magnetic Anisotropic Co²⁺Such technology, but they are not to reduce coercivity as a purpose.In addition, to aftermentioned abnormal grain Countermeasure it is insufficient therefore also poor in terms of cost and manufacture efficiency.

Inhibit appearance, the energy of abnormal grain in this regard, being reported in patent document 7 by forming setting regulation to impurity Enough stable high resistance MnCoZn ferrites manufactured and coercivity is low.

It is locally broken it should be noted that abnormal grain growth refers in the balance for making grain growth because of certain reason What bad when occurred, be the phenomenon that being frequently observed when using the manufacture of powder metallurgic method.It is mixed into the misgrowth crystal grain There are impurity, lattice defect etc. to interfere the substance of the movement of neticdomain wall significantly, therefore, loses soft magnetism characteristic, coercivity increases.Together When, crystal boundary formation becomes inadequate, therefore resistivity reduces.

Existing technical literature

Patent document

Patent document 1: Japanese Unexamined Patent Publication 7-230909 bulletin

Patent document 2: Japanese Unexamined Patent Publication 2000-277316 bulletin

Patent document 3: Japanese Unexamined Patent Publication 2001-220222 bulletin

Patent document 4: No. 3418827 bulletins of Japanese Patent No.

Patent document 5: Japanese Unexamined Patent Publication 2001-220221 bulletin

Patent document 6: Japanese Unexamined Patent Publication 2001-68325 bulletin

Patent document 7: No. 4554959 bulletins of Japan Patent

Patent document 8: Japanese Unexamined Patent Publication 2006-44971 bulletin

Summary of the invention

Problem to be solved by the invention

By the exploitation of above patent document 7, the satisfactory MnCoZn ferrite of magnetic characteristic has been obtained.

On the other hand, the trend of the Denso of automobile is significant in recent years, and MnCoZn ferrite is equipped on the feelings in automobile Condition also increases, still, this with the characteristic being taken seriously on the way be mechanical strength.With as main application up to the present Electric product or industry are compared with equipment, in the car since vibration can be generated when driving, it is vehicle-mounted on the way, for As the MnCoZn ferrite of ceramics, also require because defect does not occur under impacting caused by vibrating.

But Fe₂O₃MnCoZn ferrite of the ingredient less than 50 moles of % is sintered in calcining and is easy since Lacking oxygen is few It carries out, therefore is easy residual vacancies in crystal grain, and the generation of crystal boundary is easy to become uneven.As a result, existing as follows Problem: by from external impact, defect is easy to happen compared with existing MnCoZn ferrite.

That is, obtained magnetic characteristic is abundant in technology disclosed in Patent Document 7, but then, the defect is being fought Mechanical strength not necessarily abundant this respect still residue problem.

It should be noted that it has been known that there is in 0.01~0.5 matter in patent document 8 as the technology for improving defect intensity TiO is added in the range of amount %₂Technology.

But on the other hand, TiO is added₂Solid solution can occur in crystal grain and generate Ti⁴⁺, since valence mumber balances, a part Fe³⁺It is reduced into Fe²⁺, therefore presence leads to the shortcomings that being greatly reduced of resistivity.

The purpose of the present invention is to provide a kind of MnCoZn ferrite and its advantageous manufacturing method, the MnCoZn iron oxygen Body keeps existing high resistance, low-coercivity magnetic characteristic good in this way, and by pressing down while generating uniform crystal boundary Abnormal grain growth processed also has both mechanical strength as the fracture resistance indicated with wearing valve.

The method for solving problem

The present inventor is first to the ferritic Fe of MnCoZn needed for desired magnetic characteristic in order to obtain₂O₃, ZnO and CoO Appropriate amount studied, as a result, it has been found that can be achieved at the same time, resistivity is high, coercivity is small and Curie temperature is high in this way The proper range of complete characteristic.

It should be noted that in the present specification, as described above, about coercivity, using the value at 23 DEG C as problem.This Be because, antenna, noise filter purposes used in MnZn ferrite core, leaving the power supply transformation as heat source The position of device or semiconductor uses also more, they work under room temperature (5~35 DEG C).Therefore, as room temperature (5~35 DEG C) Having excellent magnetic characteristics at 23 DEG C of the typical value of range, i.e. coercivity is small is important.

Then, it is conceived to microstructure, discovery is by reducing the vacancy in crystal grain, regular grain size and realizing appropriate thick The crystal boundary of degree is able to suppress the defect of the sintering core indicated with wearing valve.Here, in order to realize desired crystalline structure, as In the SiO for the ingredient that crystal boundary is segregated₂And the additive amount of CaO has a significant impact, and therefore, has been successfully determined these ingredients Appropriate range.When in the range, it is able to maintain low wearing valve.

In addition, in order to have both magnetic characteristic appropriate and to anti-defect mechanical strength and indispensable exception is brilliant The inhibition that grain occurs, is conceived to manufacturing conditions when abnormal grain occurs and is studied, as a result, it has been found that, in above-mentioned SiO₂And It is mixed as miscellaneous in the case that CaO is excessive and containing more than certain value existing in natural crystal or when smelting In the case where the ingredients such as Cd, Pb, Sb, As and Se of matter, abnormal grain occurs.

The present invention is based on above-mentioned opinion.

It should be noted that as described above, in patent document 1, patent document 2 and patent document 3 etc., about high electricity Mentioned by resistance rate has, in addition, in patent document 4, patent document 5 and patent document 6, about with positive magnetic anisotropy Co²⁺Added with described, but not about coercitive record, in patent document 5, define: leading on the contrary more instead Pb is added dynamicly.Moreover, all absolutely not recorded in these Patent Documents 1 to 6 about abnormal grain countermeasure, it is inferred that Mechanical strength is also insufficient out.Even in addition, having mentioned patent document 7, the regulation of additive about low-coercivity It is insufficient, therefore it could not be expected that can inhibit the sufficient mechanical strength of defect.Even in addition, the improvement about defect intensity There is mentioned patent document 8, also not can avoid being greatly reduced for resistivity.

Purport of the invention constitutes as described below.

1. a kind of MnCoZn based ferrite,

As basis, contain iron: with Fe₂O₃Conversion meter 45.0 moles of % more than and less than 50.0 moles %, zinc: with ZnO conversion meter 15.5~24.0 moles of %, cobalts: 0.5~4.0 mole of % and manganese in terms of CoO conversion: surplus,

Contain SiO as accessory ingredient relative to above-mentioned basis₂: 50~300 mass ppm and CaO:300~ 1300 mass ppm,

Surplus is made of inevitable impurity, wherein

Cd, Pb, Sb, As and Se amount in above-mentioned inevitable impurity is suppressed to respectively less than 20 mass ppm,

Also, the wearing valve of above-mentioned MnCoZn based ferrite less than the coercivity at 0.85%, 23 DEG C be 15A/m or less, Resistivity is 30 Ω m or more and Curie temperature is 100 DEG C or more.

2. the MnCoZn based ferrite as described in above-mentioned 1, wherein the sintered density of above-mentioned MnCoZn based ferrite is 4.85g/cm³More than.

3. the MnCoZn based ferrite as described in above-mentioned 1 or 2, wherein above-mentioned MnCoZn based ferrite is by size distribution The value of d90 is the MnCoZn based ferrite that forming-sintered body of 300 μm of pelletizings below is formed.

4. the MnCoZn based ferrite as described in above-mentioned any one of 1~3, wherein above-mentioned MnCoZn based ferrite be by The MnCoZn based ferrite that forming-sintered body of pelletizing of the crushing strength less than 1.50MPa is formed.

5. a kind of manufacturing method of MnCoZn based ferrite, includes

Pre-burning process carries out pre-burning to the mixture of the basis weighed in a manner of reaching scheduled component ratio；

Mixing-pulverizing process, addition is adjusted to the pair of estimated rate in the pre-burning powder obtained by above-mentioned pre-burning process Ingredient is mixed, is crushed；With

Calcination process, after adhesive is added in the comminuted powder obtained by above-mentioned mixing-pulverizing process and is mixed, It is granulated in a manner of making 300 μm of value or less of size distribution d90 of pelletizing and/or crushing strength be less than 1.50MPa, After obtained pelletizing is formed, highest keep temperature be 1290 DEG C or more, the item that the retention time is 1 hour or more Calcined under part, obtain above-mentioned 1 or 2 described in MnCoZn based ferrite.

6. the manufacturing method of the MnCoZn based ferrite as described in above-mentioned 5, wherein above-mentioned granulation is spray drying process.

Invention effect

According to the present invention it is possible to obtain not only have high resistance, low-coercivity magnetic characteristic good in this way and by Inhibit abnormal grain growth while generating uniform crystal boundary and has both mechanical strength as excellent fracture resistance MnCoZn ferrite.

MnCoZn ferrite of the invention is 3000 or more and 23 DEG C, 1MHz with the initial permeability under 23 DEG C, 1kHz Under initial permeability be 2000 or more and 23 DEG C, the initial permeability under 10MHz is that 150 or more such excellent magnetic are special Property.

Specific embodiment

Hereinafter, the present invention is concretely demonstrated.

Firstly, being illustrated to the reasons why the ferritic composition of MnCoZn is limited to above range in the present invention.It needs It is noted that about the iron, zinc, cobalt, the manganese that contain in the present invention as basis, to be converted into Fe₂O₃、ZnO、 The value of CoO, MnO indicate.In addition, about these Fe₂O₃, ZnO, CoO, MnO content, indicated with a mole %, on the other hand, close In the content of accessory ingredient and impurity component, indicated with the quality ppm relative to ferrite entirety.

Fe₂O₃: more than and less than 50.0 moles % of 45.0 moles of %

Fe₂O₃It is excessive to contain sometimes, Fe²⁺Amount increases, and the ferritic resistivity of MnCoZn reduces as a result,.In order to avoid above-mentioned Situation, Fe₂O₃Amount needs to be suppressed to less than 50 moles %.But when very few, lead to coercitive raising and Curie temperature It reduces, therefore, iron is with Fe₂O₃Conversion meter at least contains 45.0 moles of %.Preferred Fe₂O₃Range be 47.1 moles of % or more And less than 50.0 moles %, more preferably 47.1~49.5 moles of %.

ZnO:15.5 moles of %~24.0 mole %

ZnO have make ferritic saturated magnetization increase and due to saturated vapour pressure is lower and increase sintered density, Make the raised effect of saturation flux density, is for reducing the effective ingredient of coercivity.Therefore, zinc is at least contained in terms of ZnO conversion There are 15.5 moles of %.On the other hand, when Zn content is more than appropriate value, leads to the reduction of Curie temperature, there is problem in practical. Therefore, the upper limit is set as 24.0 moles of % in terms of ZnO conversion by zinc.The range of preferred ZnO is 15.5~23.0 moles of %, more Preferably 17.0~23.0 moles of %.

CoO:0.5 moles of %~4.0 mole %

Co in CoO²⁺The ion with positive magnetic anisotropy energy, with the CoO appropriate amount addition, magnetic respectively to The absolute value of the summation of anisotropic energy reduces, and as a result realizes coercitive reduction.For this reason, it may be necessary to add 0.5 mole of %'s or more CoO.On the other hand, the summation that a large amount of additions lead to the reduction of resistivity, induce abnormal grain growth and magnetic anisotropy energy Excessively just inclining, therefore is instead resulting in coercitive raising.Above situation in order to prevent, CoO at most add 4.0 moles of %.It is preferred that CoO range be 1.0~3.5 moles of %, more preferably 1.0~3.0 moles of %.

MnO: surplus

The present invention is MnCoZn ferrite, and the surplus of basis composition needs for MnO.The reason for this is that if not MnO is then unable to get the good magnetic characteristic of high saturation magnetic flux density, low-loss and high magnetic permeability.The range of preferred MnO For 26.5~32.0 moles of %.

More than, basis is illustrated, about accessory ingredient, as described below.

SiO₂: 50~300 mass ppm

SiO₂The known homogenization for facilitating ferritic crystalline structure, with suitable addition, so that residual in crystal grain Vacancy reduce so that relict flux density reduce so that coercivity reduce.In addition, SiO₂It is inclined by occurring in crystal boundary It analyses and improves resistivity, while making thick large-sized crystallization reduction, therefore the mill of the index of defect as sintered body can be made Consumption value reduces.Therefore, the SiO at least containing 50 mass ppm₂.On the other hand, when additive amount is excessive, will appear on the contrary abnormal brilliant Grain, this becomes the starting point of defect, therefore wearing valve increases, while coercivity also increases, therefore, SiO₂Be limited to containing in need 300 mass ppm or less.Preferred SiO₂Content be 60~250 mass ppm range.

The mass of CaO:300~1300 ppm

CaO is segregated in the ferritic crystal boundary of MnCoZn, has the function of inhibiting grain growth, also has and reduce in crystalline substance The effect in the remaining vacancy of intragranular.Therefore, with suitable addition, resistivity is increased, and coercivity also declines, and makes coarse Crystallization reduce, therefore, wearing valve also can reduce.Therefore, the CaO at least containing 300 mass ppm.On the other hand, additive amount When excessive, there is abnormal grain, wearing valve and coercivity also increase, and therefore, CaO's is limited to 1300 mass containing in need Ppm or less.The range that the content of preferred CaO is 350~1000 mass ppm.

Then, the impurity component that should inhibit is illustrated.

Cd, Pb, Sb, As and Se is set to be respectively smaller than 20 mass ppm

These ingredients are to contain in natural crystal or inevitable in the feed due to the reasons such as being mixed into when smelting The ingredient that ground contains.They containing in denier, there is no problem, but containing it is a certain amount of above when, induce ferritic exception Grain growth brings serious adverse effect to obtained ferritic each characteristic.It contains only as in the present invention less than 50 The Fe of mole %₂O₃Composition ferrite compared with the situation containing 50 moles of % or more, the grain growth of crystallization be easy into Row, therefore, Cd, Pb, Sb, As and Se amount are easy to happen abnormal grain growth when more.In this case, not only coercivity liter Height, and the generation of crystal boundary becomes inadequate, and therefore, resistivity reduces, and becomes the starting point of defect, therefore wearing valve also rises It is high.

Therefore, in the present invention, the content of Cd, Pb, Sb, As and Se are suppressed to respectively less than 20 mass ppm.

It should be noted that the allowance of inevitable impurity is including above-mentioned Cd, Pb, Sb, As and Se with whole Body meter needs to be set as 50 mass ppm or less.It is preferred that the allowance of the inevitable impurity is 40 mass ppm or less.

It is therefore preferable that inhibiting as raw material mixing for the basis used and the impurity in accessory ingredient as much as possible Enter.The total amount of the impurity in basis and accessory ingredient used as raw material include above-mentioned Cd, Pb, Sb, As and Se is preferably set to 50 mass ppm inside hereinafter, being more preferably set as 40 mass ppm or less.

In addition, being not limited to form, the ferritic each characteristic of MnCoZn is also by the very big influence of various parameters.Therefore, exist In the present invention, in order to preferably satisfy following conditions with desired magnetic characteristic, strength characteristics.

Sintered density: 4.85g/cm³More than

For MnCoZn ferrite, by calcination processing make sintering and grain growth carry out, constitute crystal grain with And crystal boundary.Suitably exist to realize the crystalline structure of achievable low-coercivity, should be present in the non-magnetic constituents of crystal boundary Cyrystal boundary segregation, the partial size for making crystal grain keep appropriateness and the form by having uniform magnetic ingredient to constitute, need to make to be sintered Reaction is sufficiently carried out.In addition, from the viewpoint of preventing defect, the strength reduction in the case where being sintered insufficient, therefore Not preferably.

From the above point of view, the preferred sintered density of MnCoZn ferrite of the invention is set as 4.85g/cm³More than.It is logical It crosses and meets above-mentioned condition, coercivity reduces, and wearing valve can be made to inhibit lower.It should be noted that in order to realize this Sintered density needs to keep temperature to be set as 1290 DEG C or more and by the retention time at this temperature highest when calcining It is set as 1 hour or more to be calcined.Preferably, highest holding temperature is 1290~1400 DEG C, the retention time is 1~8 Hour.In addition, sintered density does not improve in the case where being abnormal grain growth, and therefore, in order not to abnormal grain occur, It needs to be restricted to make in appropriate range by addition object amount as described above, impurity level.

Value using size distribution d90 is that 300 μm of pelletizings below are made.

Pelletizing using pelletizing crushing strength less than 1.50MPa is made.

In general, the powder that MnCoZn ferrite is compressed after pelletizing is filled in mold with the pressure of about 100MPa Last forming process and to obtained formed body carry out calcining obtain its sintering.On the ferritic surface, because of pelletizing Minute asperities caused by mutual gap also remain after sintering, the starting point of defect when becoming impact, therefore, with small recessed Convex remaining increase, wearing valve improve.Therefore, in order to reduce the mutual gap of pelletizing, the granulation of coarse size is preferably removed Powder and the crushing strength of pelletizing is also suppressed to certain value or less.

It is adjusted about granularity by making obtained pelletizing sieving as the effective means for meeting the condition Granularity is effective.On the other hand, in order to reduce the crushing strength of pelletizing, apply heat like that in spray granulation to carry out When granulation, it is effective for improving temperature excessively.About size distribution, by being spread out based on the laser recorded in JIS Z 8825 The partial size parsing for penetrating scattering method is measured." d90 " indicate size distribution curve in, from small particle side volume add up be 90% partial size.In addition, the crushing strength about pelletizing, is measured by method specified in JIS Z 8841.

It should be noted that making mobility because of the increase of the contact point between pelletizing when the value of size distribution d90 is too small It reduces, therefore, leads to the problem of forming pressure increase when the bad and forming of the mold filling of powder when powder forming, because This, the lower limit of d90 is preferably set to 75 μm.In addition, when pelletizing crushing strength is greatly reduced, in conveying and the mold of powder When filling, pelletizing is crushed, mobility reduce, thus still can generate powder mold filling when it is bad and forming when The problem of forming pressure increases, therefore, the lower limit of crushing strength is preferably set to 0.50MPa.

Then, the ferritic manufacturing method of MnCoZn of the invention is illustrated.

About the ferritic manufacture of MnCoZn, Fe is weighed in a manner of reaching scheduled ratio first₂O₃, ZnO, CoO and MnO powder carries out pre-burning after being sufficiently mixed them.Then, obtained pre-burning powder is crushed, obtains comminuted powder.At this point, with Accessory ingredient specified in the scheduled ratio addition present invention, is crushed together with pre-burning powder.In this process, in order to make to add The concentration of ingredient powder is sufficiently carried out and is homogenized there is no unevenness, while miniaturize pre-burning powder to target and being averaged grain The size of diameter.Here, the average grain diameter of the comminuted powder as target is 1.4~1.0 μm.

Then, the organic matters adhesives such as polyvinyl alcohol are added in the powder that target composition is made, it is desired in order to obtain Pelletizing is made by the granulation based on spray drying process etc. under suitable condition in the sample of granularity and crushing strength.Spray When mist seasoning, preferably make temperature of outgoing air lower than 270 DEG C.Here, the preferred size of pelletizing is calculated as with the value of size distribution d90 75~300 μm.In addition, the preferred crush strength of pelletizing is 0.50MPa more than and less than 1.50MPa.

Then, after as needed through processes such as the sievings adjusted for granularity, using forming machine apply pressure carry out at After shape, calcined under calcination condition appropriate.It is preferred that passing through the sieve of 350 μm of meshes and removing the coarse powder on sieve.

It should be noted that calcination condition appropriate refers to that highest keeps temperature to be 1290 DEG C or more, keep as described above Time is 1 hour or more.

In addition, the processing such as surface grinding also can be implemented in obtained ferrite cemented body.

Thus, it is possible to obtain MnCoZn ferrite that is previous impossible while meeting following whole good characteristics.

Wearing valve is less than 0.85%

Coercivity at 23 DEG C is 15A/m or less

Resistivity is 30 Ω m or more

Curie temperature is 100 DEG C or more

Embodiment

Embodiment 1

By contained iron, zinc, cobalt and manganese all with Fe₂O₃, ZnO, CoO and MnO form when being converted, with Make Fe₂O₃, ZnO, CoO and MnO amount become the mode of ratio shown in table 1 and weigh each raw material powder, which is made After being mixed 16 hours with ball mill, in air in 925 DEG C of progress pre-burning in 3 hours.Then, for the pre-burning powder, difference is weighed It is equivalent to the SiO of 150 mass ppm, 700 mass ppm₂, add after CaO, utilize ball mill to crush 12 hours.Then, in gained To crushing slurry in add polyvinyl alcohol, temperature of outgoing air be 250 DEG C at carry out spray drying granulation, pass through 350 μm of mesh Screen out coarse powder after, apply the pressure of 118MPa and be configured to toroidal cores and cuboid core.Granulation used in forming The size distribution d90 of powder is 230 μm and crushing strength is 1.29MPa.

Then, which is fitted into calcining furnace, properly mixes nitrogen with air at 1350 DEG C of maximum temperature Made of calcine 2 hours in air-flow, obtain outer diameter be 25mm, internal diameter 15mm, be highly 5mm sintered body toroidal cores and 5 Diameter is 10mm, is highly the cylindric core of sintered body of 10mm.

Due to using high-purity raw, impurity Cd, Pb, Sb, As and Se of sintered body core are 3 mass ppm.

It should be noted that the content of Cd, Pb, Sb, As and Se are carried out according to JIS K 0102 (IPC mass spectrometry) It is quantitative.

For obtained sample, it is based on JIS C 2560-2, toroidal cores are measured by Archimedes method at 23 DEG C Sintered density measures resistivity by four-terminal method.About the initial permeability of toroidal cores, 10 circle windings are implemented to toroidal cores, Using LCR tester (4980A of Keysight company manufacture) measurement inductance, the inductance based on measurement is calculated.In addition, occupying In temperature calculated by the temperature characterisitic measurement result of inductance.About wearing valve, according to side specified in JPMAP11-1992 Method is measured.Coercivity H is based on JIS C 2560-2 and is measured at 23 DEG C.

Obtained result is remembered together in table 1.

As shown in the table, in embodiment 1-1~1-7 as example, the available wearing valve that has both is less than Resistivity at 0.85% high intensity and 23 DEG C is 30 Ω m or more, coercivity is 15A/m or less and Curie temperature is The MnCoZn ferrite of 100 DEG C or more of excellent magnetic characteristic.

In contrast, in the Fe containing 50.0 moles of % or more₂O₃Comparative example 1-1,1-2 in, with Fe²⁺Generation, Resistivity is greatly reduced.On the other hand, in Fe₂O₃It measures in the comparative example 1-3 less than 45.0 moles of %, observes coercitive liter High and Curie temperature reduction.

In addition, observing the reduction of Curie temperature in the comparative example 1-4 that ZnO amount is more than proper range.On the other hand, In the comparative example 1-5 that ZnO amount is unsatisfactory for proper range, coercivity is increased, and is not able to achieve preferred magnetic characteristic.

In addition, due to the deficiency of positive magnetic anisotropy, being rectified in the comparative example 1-6 that CoO amount is unsatisfactory for proper range Stupid power is high, on the other hand, in the comparative example 1-7 that CoO amount is more than proper range, also due to positive magnetic anisotropy excessively mentions Height, therefore coercivity increases, and is detached from preferred range.

Embodiment 2

By contained iron, zinc, cobalt and manganese all with Fe₂O₃, ZnO, CoO and MnO meter conversion when, to form Fe₂O₃ Amount is that the mode that 49.0 moles of %, ZnO amounts are the composition that 21.0 moles of %, CoO amounts are 2.0 moles of % and surplus is MnO claims Content of starting materials, after being mixed 16 hours using ball mill, in air in 925 DEG C of progress pre-burning in 3 hours.Then, for the pre-burning powder, Add the SiO of amount shown in table 2₂, CaO, utilize ball mill carry out 12 hours crush.Then, in obtained crushing slurry, Add polyvinyl alcohol, temperature of outgoing air be 250 DEG C at carry out spray drying granulation, by 350 μm of mesh screen out coarse powder after, Apply the pressure of 118MPa and is configured to toroidal cores and cylindrical core.It should be noted that pelletizing used in forming Size distribution d90 is 230 μm, crushing strength 1.29MPa.

Then, which is fitted into calcining furnace, properly mixes nitrogen with air at 1350 DEG C of maximum temperature Made of calcine 2 hours in air-flow, obtain outer diameter be 25mm, internal diameter 15mm, be highly 5mm sintered body toroidal cores and 5 Diameter is 10mm, is highly the cylindric core of 10mm.

It should be noted that due to using high-purity raw as raw material, impurity Cd, Pb of sintered body core, Sb, As and Se is 3 mass ppm.

For these each samples, each characteristic is evaluated using method, apparatus same as Example 1.

Obtained result is remembered together in table 2.

As shown in the table, in SiO₂And CaO amount be proper range in embodiment 2-1~2-4 in, can be had both Resistivity at high intensity of the wearing valve less than 0.85% and 23 DEG C is 30 Ω m or more, coercivity is 15A/m or less and occupies In temperature be 100 DEG C or more excellent magnetic characteristic MnCoZn ferrite.

In contrast, in SiO₂, any of CaO be unsatisfactory in comparative example 2-1,2-3 of proper range, the life of crystal boundary At insufficient, thus the size of crystal grain is uneven, and therefore, wearing valve is higher than 0.85%, and crystal boundary thickness is also insufficient, therefore Resistivity is less than 30 Ω m.

In addition, there is abnormal grain under one kind excessive comparative example 2-2,2-4 and 2-5 in this composition is horizontal, Sintering is hindered, and therefore, sintered density is low, and wearing valve is also high.In addition to this, the generation of crystal boundary is insufficient, therefore, resistivity Low and coercivity also increases.

Embodiment 3

By method shown in embodiment 1,2, become identical with embodiment 1-2 using basis and accessory ingredient The ratio of composition but a variety of different raw materials of contained impurity level produce outer diameter and are 25mm, internal diameter 15mm, are highly The sintered body toroidal cores of 5mm and 5 diameters are 10mm, are highly the cylindric core of 10mm, use side same as Example 1 Method, device evaluate characteristic, show the result in table 3.It should be noted that the granularity of pelletizing used in forming Being distributed d90 is 230 μm, crushing strength 1.29MPa.

It as shown in the table, is to be obtained in specified value embodiment 3-1 below in the content of Cd, Pb, Sb, As and Se The all good value of magnetic characteristic represented by intensity represented by wearing valve and coercivity, resistivity and Curie temperature.

In contrast, one or more of this 5 levels are more than and occur in comparative example 3-1~3-7 of specified value Abnormal grain, sintering are hindered, thus sintered density is low, and therefore, wearing valve is high, and the generation of crystal boundary is insufficient, therefore, Resistivity is low, and then coercivity also increases.

Embodiment 4

It, will be so that basis, accessory ingredient and impurity component become and embodiment by method shown in embodiment 1,2 It is calcined under the conditions of formed body various temperature shown in table 4 of the ratio production of 1-2 same composition.

For these each samples, each characteristic is evaluated using method, apparatus same as Example 1.By gained To result remembered in table 4 together.It should be noted that the size distribution d90 of pelletizing used in forming is 230 μm, Crushing strength is 1.29MPa.

As shown in the table, the highest holding temperature in calcining is 1290 DEG C or more and the retention time is 1 hour or more Come calcined, sintered density 4.85g/cm³In above embodiment 3-1~3-5, intensity represented by wearing valve and Magnetic characteristic represented by resistivity, coercivity and Curie temperature is all good.

In contrast, it is less than lower than 1290 DEG C or retention time less than 1 hour, sintered density in calcination temperature 4.85g/cm³Comparative example 3-1~3-6 in, sintered density is low, and therefore, wearing valve increases, and crystal grain-growth is insufficient, because This magnetic hystersis loss increases, as a result, coercivity increases, it is not preferred from intensity, the two viewpoints of magnetic characteristic.

Embodiment 5

By method shown in embodiment 1,2, for composition identical with embodiment 1-2, in same spray dried strip The pelletizing obtained under part, the sample (crushing to the value of size distribution d90 shown in table 5 is made by changing sieving condition Intensity: 1.29MPa) apply the pressure of 118MPa and shapes toroidal cores and cylindrical core.Then, which is packed into and is calcined In furnace, calcined 2 hours in the air-flow made of properly mixing nitrogen and air at 1350 DEG C of maximum temperature, obtaining outer diameter is It 25mm, internal diameter 15mm, is highly the sintered body toroidal cores of 5mm and 5 diameters are 10mm, are highly the cylindric core of 10mm.

For these each samples, each characteristic is evaluated using method, apparatus same as Example 1.By gained To result remembered in table 5 together.

It as shown in the table, is in 300 μm of embodiment 5-1 below, between pelletizing in the value of pelletizing size distribution d90 The residual in gap is few, and the starting point of defect is few, therefore, wearing valve can be suppressed to 0.85% or less.

In contrast, in comparative example 5-1~5-3 of the value of d90 greater than 300 μm, the gap between pelletizing is more, defect Starting point is more, and therefore, wearing valve is high, strength reduction.

Embodiment 6

The slurry made is formed in table 6 to identical with the embodiment 1-2 by the production of method shown in embodiment 1,2 Shown in be spray-dried under the conditions of temperature of outgoing air, thus obtain the different pelletizing of crushing strength, pass through 350 μm of mesh After screening out coarse powder, applies the pressure of 118MPa and be configured to toroidal cores and cylindrical core.It should be noted that granulation at this time The size distribution d90 of powder is 230 μm.

For these each samples, each characteristic is evaluated using method, apparatus same as Example 1, by result Remembered in table 6 together.

As shown in the table, do not have in excessively high embodiment 1-2,6-1 in the temperature of outgoing air of spray drying granulation, pelletizing Crushing strength is less than 1.5MPa, and pelletizing is sufficiently crushed when forming, therefore, does not remain the gap between pelletizing, thus lacks The starting point of damage is few, and therefore, wearing valve can be suppressed to less than 0.85%.

In contrast, be conceived to the excessively high pelletizing crushing strength of temperature of outgoing air be 1.5MPa or more comparative example 6-1~ When 6-3, because pelletizing crush it is bad caused by defect starting point it is more, therefore, wearing valve increase, strength reduction.

Claims

1. a kind of MnCoZn based ferrite,

As basis, contain iron: with Fe₂O₃Conversion meter 45.0 moles of % more than and less than 50.0 moles %, zinc: it is changed with ZnO Calculate 15.5~24.0 moles of %, cobalts: 0.5~4.0 mole of % and manganese in terms of CoO conversion: surplus,

Contain SiO as accessory ingredient relative to the basis₂: 50~300 mass mass of ppm and CaO:300~1300 Ppm,

Surplus is made of inevitable impurity, wherein

Cd, Pb, Sb, As and Se amount in the inevitable impurity is suppressed to respectively less than 20 mass ppm,

Also, the wearing valve of the MnCoZn based ferrite is 15A/m or less, resistance less than the coercivity at 0.85%, 23 DEG C Rate is 30 Ω m or more and Curie temperature is 100 DEG C or more.

2. MnCoZn based ferrite as described in claim 1, wherein the sintered density of the MnCoZn based ferrite is 4.85g/cm³More than.

3. MnCoZn based ferrite as claimed in claim 1 or 2, wherein the MnCoZn based ferrite is by size distribution The value of d90 is the MnCoZn based ferrite that forming-sintered body of 300 μm of pelletizings below is formed.

4. MnCoZn based ferrite according to any one of claims 1 to 3, wherein the MnCoZn based ferrite be by The MnCoZn based ferrite that forming-sintered body of pelletizing of the crushing strength less than 1.50MPa is formed.

5. a kind of manufacturing method of MnCoZn based ferrite, includes

Mixing-pulverizing process, addition is in the pre-burning powder obtained by the pre-burning process to reach scheduled component ratio The accessory ingredient that mode adjusts, and mixed, crushed；With

Calcination process, after adhesive is added in the comminuted powder obtained by the mixing-pulverizing process and is mixed, so that The value of the size distribution d90 of pelletizing is 300 μm or less and/or mode of the crushing strength less than 1.50MPa is granulated, to institute After obtained pelletizing is formed, under conditions of keeping temperature in highest is 1290 DEG C or more, the retention time is 1 hour or more It is calcined, obtains MnCoZn based ferrite of any of claims 1 or 2.

6. the manufacturing method of MnCoZn based ferrite as claimed in claim 5, wherein described be granulated is spray drying process.