JP2008290906A - METHOD OF MANUFACTURING MnZn-BASED FERRITE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing MnZn-based ferrite by which variation of characteristics between product lots is suppressed and production yield and reliability of product quality are improved even when Li is added to the MnZn-based ferrite. <P>SOLUTION: In the manufacturing method of the MnZn-based ferrite prepared by adding Li as an assistant component to the MnZn-based ferrite of the main component, an Li compound to be used when adding Li is a component insoluble or hardly soluble in water. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a MnZn-based ferrite that can suppress variation in characteristics between product lots, improve production yield, and improve product quality reliability.

  In recent years, electronic devices have been rapidly reduced in size and output. Along with this, various components have been highly integrated and high-speed processing has progressed, and there has been a demand for increasing the current of the power supply line for supplying power. Drives with high power are also required for components such as transformers and choke coils. Furthermore, stable driving at around 100 ° C is required due to high temperatures in the usage environment of automobiles and temperature rise due to heat generated during driving. It has been.

  In order to cope with a large current drive, the ferrite core is required to have a high saturation magnetic flux density at a high temperature, for example, in a temperature region of 100 ° C. or higher.

In order to meet such a demand, for example, Japanese Patent Laid-Open No. 2001-155915 (Patent Document 1) describes a temperature at which the composition ratio of Fe ₂ O ₃ is high, the saturation magnetic flux density is high, and the core loss is minimized. Is intended to provide a Mn—Zn ferrite material that can be easily made to a practical temperature, and as main components, Fe ₂ O ₃ : 54 to 56 mol%, ZnO: 5 to 10 mol%, MnO : The balance is contained, and Li ₂ CO ₃ : 0.1 to 0.5 wt%, CaCO ₃ : 0.01 to 0.3 wt%, SiO ₂ : 0.001 to 0.05 wt% as subcomponents There have been proposals for ferrite materials containing. Furthermore, in this proposal, it is said that the temperature at which the magnetic core loss (core loss) is minimized can be shifted to the high temperature side by adding Li.

Conventionally, the form of the Li compound used when adding Li to the MnZn-based ferrite is easy to obtain, and it is common to use Li ₂ CO ₃ whose use is widely known. .

JP 2001-155915 A

However, the inventors of the present application pay attention to (1) the type of additive when adding various additive components to the MnZn-based ferrite, and (2) the form of the compound when adding the additive. As a result of research, when Li is added, and the compound form at the time of addition is Li ₂ CO ₃ which is easily soluble in water, there is a tendency that characteristic variation between product lots is likely to occur. I found it experimentally.

  The characteristic variation between the ferrite product lots may cause a decrease in the product yield and may impair the quality assurance of the product, and it is necessary to reduce the characteristic variation as much as possible in the manufacturing stage.

  Under such circumstances, the present invention has been devised, and its purpose is to add Li to MnZn-based ferrite, which can suppress variation in characteristics between product lots. Another object of the present invention is to provide a method for producing a MnZn-based ferrite capable of improving the production yield and improving the reliability of product quality.

  In order to solve such a problem, the present invention relates to a Li compound used for adding Li in a method for producing MnZn ferrite comprising adding Li as a subcomponent to a main component of MnZn ferrite. Is configured to be a compound that is insoluble or hardly soluble in water.

Further, as a preferred embodiment of the present invention, the MnZn-based ferrite comprises iron oxide as a main component in an amount of 54 to 60 mol% in terms of Fe ₂ O ₃ , zinc oxide in an amount of 3 to 10 mol% in terms of ZnO, and manganese oxide (in terms of MnO). ) In the remainder.

As a preferred embodiment of the present invention, the Li compound is configured to be contained in an amount of 0.1 to 0.8% by weight with respect to the main component in terms of Li ₂ CO ₃ .

  As a preferred embodiment of the present invention, the Li compound is configured to be an oxide containing Li and at least one component selected from Fe, Mn, and Zn.

  As a preferred embodiment of the present invention, the Li compound is configured to be an oxide containing components of Li and Fe.

As a preferred embodiment of the present invention, the Li compound is configured to be at least one selected from LiFeO ₂ , LiFe ₅ O ₈ , Li ₂ Fe ₃ O ₅ , and Li ₅ FeO _4. The

  Moreover, as a preferable aspect of the present invention, the Li compound is configured to be an oxide containing components of Li and Mn.

Moreover, as a preferable aspect of the present invention, the Li compound is configured to be at least one selected from LiMn ₂ O ₄ and LiMnO ₂ .

  Further, as a preferred embodiment of the present invention, it is further configured to contain at least one selected from Si, Ca, Zr, Nb, Ta, V, Bi, Mo, and Sn as subcomponents. The

  The present invention relates to a method for producing MnZn-based ferrite obtained by adding Li as a minor component to the main component of MnZn-based ferrite, wherein the Li compound used when adding Li is insoluble or hardly soluble in water. Therefore, it is possible to suppress variation in characteristics between product lots, improve manufacturing yield, and improve product quality reliability.

Hereinafter, the manufacturing method of the MnZn ferrite of the present invention will be described in detail.
First, the MnZn-based ferrite that is the production target of the present invention will be described.

[ Description of MnZn-based ferrite to be produced in the present invention ]
MnZn ferrite to be manufactured of the present invention, as a main component, iron oxide 54-60 mole% calculated as Fe ₂ O ₃ (more preferably, 55.5 to 57.5 mol%), zinc oxide ZnO 3 to 10 mol% (more preferably, 5 to 8 mol%) in terms of conversion and manganese oxide (in terms of MnO) as the balance.

Furthermore, in the present invention, Li is contained as a subcomponent, and the Li is 0.1 to 0.8% by weight (more preferably, 0.8%) with respect to the main component in terms of Li ₂ CO ₃ . 3 to 0.6% by weight).

In the above composition range, when Fe ₂ O ₃ is less than 54 mol%, there is a tendency that a desired high saturation magnetic flux density characteristic cannot be obtained, while Fe ₂ O ₃ is 60%. When it exceeds mol%, the core loss tends to increase, and there is a tendency that a desired low core loss characteristic cannot be obtained.

  Moreover, when ZnO is less than 3 mol%, so-called relative density tends to decrease, and it is difficult to achieve a low core loss. On the other hand, when ZnO exceeds 10 mol%, the Curie temperature tends to decrease, and the saturation magnetic flux density at high temperatures tends to decrease.

  Moreover, when the amount of Li is less than 0.1% by weight, there is a tendency that a desired high saturation magnetic flux density cannot be obtained, and when the amount of Li exceeds 0.8% by weight, There is a tendency that inconvenience that desired low core loss characteristics cannot be obtained.

  In addition to the above-described Li, the MnZn-based ferrite to be produced according to the present invention is at least one selected from Si, Ca, Zr, Nb, Ta, V, Bi, Mo, and Sn as subcomponents. Can be contained. The preferred content (wt%) is as follows.

SiO _2: 0.005~0.03wt%
CaO: 0.008 to 0.17 wt%
Nb ₂ O ₅ : 0.005 to 0.03 wt%
Ta ₂ O ₅ : 0.01 to 0.1 wt%
V ₂ O _5: 0.01~0.1wt%
ZrO ₂ : 0.005 to 0.03 wt%
Bi ₂ O ₃ : 0.005 to 0.04 wt%
MoO ₃ : 0.005 to 0.04 wt%

  Among these, silicon oxide and calcium oxide are particularly preferable.

Next, a method for producing the MnZn ferrite of the present invention will be described.
[ Description of method for producing MnZn-based ferrite ]
The main part of the invention in the method for producing MnZn-based ferrite of the present invention is that the Li compound used when adding Li, which is a subcomponent, is an insoluble or hardly soluble compound in water.

  In the present invention, “a compound that is insoluble or hardly soluble in water (hereinafter simply referred to as“ water-insoluble compound ”)” refers to the amount of solute (grams) in 100 g of water (temperature 20 ° C.). ) Refers to a compound of 1 g or less.

  Such a water-insoluble Li compound is an oxide containing at least one component selected from Li and Fe, Mn, and Zn in order to be used for MnZn ferrite. Is desirable.

Preferably, (1) an oxide such as LiFeO ₂ , LiFe ₅ O ₈ , Li ₂ Fe ₃ O ₅ , or Li ₅ FeO ₄ containing components of Li and Fe, or (2) Li and Mn It is an oxide such as LiMn ₂ O ₄ or LiMnO ₂ containing a component.

  By using such a water-insoluble Li compound, it is possible to suppress variation in characteristics between product lots, and to improve manufacturing yield and reliability of product quality. Such a water-insoluble Li compound can be mixed with the main component in the main component composition at the initial weighing stage, or the main component powder obtained after calcining and pulverization can be mixed with the water-insoluble Li compound. Can be added and mixed. When the water-insoluble Li compound contains Fe, Mn, and Zn, the main component composition is weighed and adjusted in consideration of this amount.

In addition, such a water-insoluble Li compound may be used as it is if it is readily available as a commercially available compound. Alternatively, a water-insoluble Li compound may be produced by reaction synthesis through mixing and heat treatment steps. For example, a raw material containing Li and a raw material containing at least one component selected from Fe, Mn, and Zn are dry-mixed, and then, for example, in the air at a temperature of 700 to 1000 ° C., A water-insoluble Li compound can be obtained by heat treatment for about 1 hour. As a specific example, a LiCO ₃ raw material and an Fe ₂ O ₃ raw material are prepared and reacted and synthesized by the above-described method to obtain LiFeO ₂ .

  Hereinafter, an example of a suitable series of steps in the method for producing MnZn ferrite will be described in detail.

(1) Step of weighing so that the ratio of metal ions is a predetermined component so that a target ferrite can be obtained. As a raw material of a main component, an oxide or a compound that becomes an oxide by heating, for example, carbonate, hydroxide Powders such as oxalate and nitrate are used. What is necessary is just to select suitably the average particle diameter of each raw material powder in the range of about 0.1-3.0 micrometers. In addition, not only the raw material powder mentioned above but it is good also considering the powder of the complex oxide containing 2 or more types of metals as raw material powder. Each raw material powder is weighed so as to have a predetermined composition. As a raw material powder, a water-insoluble Li compound as a subcomponent may be weighed and mixed with the main component during the following mixing.

(2) The calcining process raw material powder after the weighed product is mixed by wet or drying, for example, wet-mixed by a ball mill, dried, pulverized and sieved, and then held within a temperature range of 700 to 1000 ° C. for a predetermined time. Calcination is performed. What is necessary is just to select suitably the holding time of calcination within the range of 1 to 5 hours.

(3) Crushing step of calcined powder After calcining, the calcined body is pulverized to an average particle size of about 0.5 to 5.0 μm, for example.

  In addition, the timing which adds the water-insoluble Li compound which is a subcomponent is not limited to what was mentioned above. For example, first, only a part of the powder (particularly, the main component) is weighed, mixed, calcined and pulverized. And it is also a preferable aspect that a predetermined amount of raw material powder of a water-insoluble Li compound, which is a subcomponent, is added to and mixed with the main component powder obtained after calcining and pulverization.

(4) Granulation / molding process The pulverized powder is granulated into granules to facilitate the subsequent molding process. At this time, it is desirable to add a small amount of an appropriate binder such as polyvinyl alcohol (PVA) to the pulverized powder. The particle size of the obtained granules is preferably about 80 to 200 μm. For example, a toroidal shaped body is formed by pressing the granulated powder.

(5) Firing step The molded body is fired in the firing step.

  In the firing step, it is necessary to control the firing temperature and firing atmosphere. Firing is performed by holding for a predetermined time in a range of 1250 to 1450 ° C. In order to sufficiently exhibit the effects of the present invention, the firing is preferably held and fired in the range of 1300 to 1400 ° C.

  Hereinafter, the present invention will be described in more detail with reference to specific examples.

[ Experimental Example I ]
( Preparation of Inventive I-1 Sample )
[Preparation step obtained by previously reacting and synthesizing LiFeO ₂ which is a water-insoluble Li compound]
Li ₂ CO ₃ powder and Fe ₂ O ₃ powder were weighed as raw materials for synthesis at such a ratio that LiFeO ₂ powder could be synthesized, and each weighed powder was dry-mixed and then heat-treated for reaction synthesis.

  The heat treatment conditions were 750 ° C. and 1 hour in air.

As a result of the heat treatment, it was confirmed by X-ray diffraction that the obtained powder was LiFeO ₂ .

[Production of MnZn-based ferrite]
Fe ₂ O ₃ powder, Mn ₃ O ₄ powder, and ZnO powder were prepared as raw materials for the main components.

In addition to the above-mentioned LiFeO ₂ , SiO ₂ powder and CaCO ₃ powder were prepared as subcomponent materials.

The main component raw materials were weighed so that the composition of the main component of ferrite was Fe ₂ O ₃ = 56.0 mol%, MnO = 37.5 mol%, ZnO = 6.5 mol%, and 16% using a wet ball mill. After wet mixing for a time, it was dried. In consideration of the amount of Fe in LiFeO ₂ added later, the Fe component was adjusted so as to finally have the same main component ratio.

  Next, the dried product was calcined in the atmosphere at 900 ° C. for 3 hours and then pulverized.

To the obtained calcined powder, LiFeO ₂ is added as an auxiliary component in an amount of 0.4% by weight (in terms of Li ₂ CO ₃ ), and SiO ₂ is finally added to the main component in an amount of 0.1%. After adding 01% by weight and CaCO ₃ to 0.08% by weight with respect to the main component, adding a binder (polyvinyl alcohol) to the mixture powder obtained by mixing and grinding, and granulating To obtain a toroidal shaped body.

Next, the obtained molded body was fired in an atmosphere having a maximum temperature of 1350 ° C. and an oxygen partial pressure controlled in an N ₂ —O ₂ mixed atmosphere to obtain a sample of the present invention I-1. The dimensions of the toroidal shape after firing were an outer diameter of 20 mm, an inner diameter of 10 mm, and a thickness of 5 mm.

( Preparation of Comparative Example I-1 Sample )
In the production of the above sample I-1 of the present invention, water-soluble Li ₂ CO ₃ was used in place of the water-insoluble compound LiFeO ₂ as a subcomponent Li raw material. Otherwise, the sample of Comparative Example I-1 was prepared in the same manner as in the preparation of the sample of the present invention I-1.

  With respect to the obtained sample of the present invention I-1 and comparative example I-1 sample, the saturation magnetic flux density Bs at 100 ° C. (measurement condition: 1194 A / m) and the core loss Pcv at 100 ° C. (measurement condition: 100 kHz, 200 mT), respectively. It was measured. The number of measured samples n was 30 each.

Using the total measured data,
(1) Average values of saturation magnetic flux density Bs and core loss Pcv (2) Maximum values of saturation magnetic flux density Bs and core loss Pcv (3) Minimum values of saturation magnetic flux density Bs and core loss Pcv (4) Saturation magnetic flux Each of density Bs and core loss Pcv (maximum value-minimum value)
(5) The respective standard deviations of the saturation magnetic flux density Bs and the core loss Pcv were obtained, and the results are shown in Table 1 below.

  In addition, the 30 raw data of the sample I-1 of the present invention and the sample of Comparative Example I-1 were plotted on a graph with Bs on the vertical axis and Pcv on the horizontal axis and shown in FIG. From FIG. 1, it is possible to visually recognize the level difference of the characteristic variation.

[ Experimental Example II ]
( Preparation of Invention II-1 Sample )
In the preparation of the above sample I-1 of the present invention, the ferrite main component composition and the Li addition amount were changed. That is, a main component material is weighed so that the ferrite main component composition is Fe ₂ O ₃ = 57.5 mol%, MnO = 36.0 mol%, ZnO = 6.5 mol%, and a wet ball mill is used. For 16 hours and then dried.

Further, LiFeO ₂ was changed to 0.6% by weight (converted to Li ₂ CO ₃ ) with respect to the main component.

  Other than that, this invention II-1 sample was produced like the said invention I-1 sample.

( Production of Comparative Example II-1 Sample )
In the preparation of the sample II-1 of the present invention, water-soluble Li ₂ CO ₃ was used in place of the water-insoluble compound LiFeO ₂ as a subcomponent Li raw material. Otherwise, the sample of Comparative Example II-1 was prepared in the same manner as in the preparation of the sample of Invention II-1.

  With respect to the sample of the present invention II-1 and the sample of Comparative Example II-1 obtained, the saturation magnetic flux density Bs at 100 ° C. (measurement conditions: 1194 A / m) and the core loss Pcv at 100 ° C. (measurement conditions: 100 kHz, 200 mT), respectively. It was measured. The number of measured samples n was 20 in each case.

Using the total measured data,
(1) Average values of saturation magnetic flux density Bs and core loss Pcv (2) Maximum values of saturation magnetic flux density Bs and core loss Pcv (3) Minimum values of saturation magnetic flux density Bs and core loss Pcv (4) Saturation magnetic flux Each of density Bs and core loss Pcv (maximum value-minimum value)
(5) The respective standard deviations of the saturation magnetic flux density Bs and the core loss Pcv were obtained, and the results are shown in Table 2 below.

[ Experimental Example III ]
( Preparation of Invention III-1 Sample )
In the preparation of the above sample I-1 of the present invention, the ferrite main component composition and the Li addition amount were changed. That is, the main component material is weighed so that the ferrite main component composition is Fe ₂ O ₃ = 59.3 mol%, MnO = 34.2 mol%, ZnO = 6.5 mol%, and a wet ball mill is used. For 16 hours and then dried.

Further, LiFeO ₂ was changed to 0.75% by weight (converted to Li ₂ CO ₃ ) with respect to the main component.

  Other than that, this invention III-1 sample was produced like the said invention I-1 sample.

( Production of Comparative Example III-1 Sample )
In the production of the sample III-1 of the present invention, water-soluble Li ₂ CO ₃ was used in place of the water-insoluble compound LiFeO ₂ as a subcomponent Li raw material. Otherwise, the sample of Comparative Example III-1 was prepared in the same manner as the sample of Invention III-1.

  With respect to the obtained sample of the present invention III-1 and comparative example III-1 sample, the saturation magnetic flux density Bs at 100 ° C. (measurement condition: 1194 A / m) and the core loss Pcv at 100 ° C. (measurement condition: 100 kHz, 200 mT) are respectively obtained. It was measured. The number of measured samples n was 20 in each case.

Using the total measured data,
(1) Average values of saturation magnetic flux density Bs and core loss Pcv (2) Maximum values of saturation magnetic flux density Bs and core loss Pcv (3) Minimum values of saturation magnetic flux density Bs and core loss Pcv (4) Saturation magnetic flux Each of density Bs and core loss Pcv (maximum value-minimum value)
(5) The respective standard deviations of the saturation magnetic flux density Bs and the core loss Pcv were obtained, and the results are shown in Table 3 below.

[ Experimental Example IV ]
( Preparation of Invention IV-1 Sample )
In the preparation of the above sample I-1 of the present invention, the ferrite main component composition and the Li addition amount were changed. That is, the main component material is weighed so that the ferrite main component composition is Fe ₂ O ₃ = 56.2 mol%, MnO = 39.8 mol%, ZnO = 4.0 mol%, and a wet ball mill is used. For 16 hours and then dried.

LiFeO ₂ was 0.4% by weight (in terms of Li ₂ CO ₃ ) with respect to the main component.

  Other than that, this invention IV-1 sample was produced like the said invention I-1 sample.

( Preparation of Comparative Example IV-1 Sample )
In the production of the inventive IV-1 sample, water-soluble Li ₂ CO ₃ was used in place of the water-insoluble compound LiFeO ₂ as the Li component of the accessory component. Otherwise, the sample of Comparative Example IV-1 was prepared in the same manner as in the preparation of the sample of the present invention IV-1.

  With respect to the obtained sample of the present invention IV-1 and Comparative Example IV-1 sample, the saturation magnetic flux density Bs at 100 ° C. (measurement condition: 1194 A / m) and the core loss Pcv at 100 ° C. (measurement condition: 100 kHz, 200 mT) are respectively obtained. It was measured. The number of measured samples n was 20 in each case.

Using the total measured data,
(1) Average values of saturation magnetic flux density Bs and core loss Pcv (2) Maximum values of saturation magnetic flux density Bs and core loss Pcv (3) Minimum values of saturation magnetic flux density Bs and core loss Pcv (4) Saturation magnetic flux Each of density Bs and core loss Pcv (maximum value-minimum value)
(5) The respective standard deviations of the saturation magnetic flux density Bs and the core loss Pcv were obtained, and the results are shown in Table 4 below.

[ Experiment V ]
( Preparation of V-1 sample of the present invention )
In the preparation of the above sample I-1 of the present invention, the ferrite main component composition and the Li addition amount were changed. That is, a main component material is weighed so that the ferrite main component composition is Fe ₂ O ₃ = 55.9 mol%, MnO = 35.1 mol%, ZnO = 9.0 mol%, and a wet ball mill is used. For 16 hours and then dried.

LiFeO ₂ was 0.4% by weight (in terms of Li ₂ CO ₃ ) with respect to the main component.

  Other than that, this invention V-1 sample was produced like the said invention I-1 sample.

( Preparation of Comparative Example V-1 Sample )
In the production of the V-1 sample of the present invention, water-soluble Li ₂ CO ₃ was used in place of the water-insoluble compound LiFeO ₂ as a subcomponent Li raw material. Other than that was carried out similarly to preparation of the sample of the said invention V-1, and produced the comparative example V-1 sample.

  With respect to the obtained sample of the present invention V-1 and the sample of comparative example V-1, the saturation magnetic flux density Bs at 100 ° C. (measurement conditions: 1194 A / m) and the core loss Pcv at 100 ° C. (measurement conditions: 100 kHz, 200 mT) are obtained. It was measured. The number of measured samples n was 20 in each case.

Using the total measured data,
(1) Average values of saturation magnetic flux density Bs and core loss Pcv (2) Maximum values of saturation magnetic flux density Bs and core loss Pcv (3) Minimum values of saturation magnetic flux density Bs and core loss Pcv (4) Saturation magnetic flux Each of density Bs and core loss Pcv (maximum value-minimum value)
(5) The respective standard deviations of the saturation magnetic flux density Bs and the core loss Pcv were obtained, and the results are shown in Table 5 below.

In addition, in the above Experimental Examples I to V, even when LiFe ₅ O ₈ , Li ₂ Fe ₃ O ₅ , and Li ₅ FeO ₄ were used instead of LiFeO ₂ that was an addition form of Li, the above experimental examples were used. It has been confirmed that the same effect as shown in I to Experimental Example V appears.

[ Experimental Example VI ]
( Preparation of Sample VI-1 of the Invention )
In the production of the above sample I-1 of the present invention, the addition form of LiFeO ₂ added as the Li component was replaced with LiMn ₂ O ₄ . Consideration was made so that the amounts of Fe and Mn as main components accompanying the change of the addition form were not substantially changed.

  Other than that, this invention VI-1 sample was produced like the said invention I-1 sample.

( Production of Comparative Example VI-1 Sample )
In the production of the VI-1 sample of the present invention, water-soluble Li ₂ CO ₃ was used in place of the water-insoluble compound LiMn ₂ O ₄ as a subcomponent Li raw material. Otherwise, the sample of Comparative Example VI-1 was prepared in the same manner as in the preparation of the sample of the present invention VI-1.

  With respect to the obtained sample of the present invention VI-1 and the comparative example VI-1 sample, the saturation magnetic flux density Bs at 100 ° C. (measurement conditions: 1194 A / m) and the core loss Pcv at 100 ° C. (measurement conditions: 100 kHz, 200 mT), respectively. It was measured. The number of measured samples n was 20 in each case.

Using the total measured data,
(1) Average values of saturation magnetic flux density Bs and core loss Pcv (2) Maximum values of saturation magnetic flux density Bs and core loss Pcv (3) Minimum values of saturation magnetic flux density Bs and core loss Pcv (4) Saturation magnetic flux Each of density Bs and core loss Pcv (maximum value-minimum value)
(5) The respective standard deviations of the saturation magnetic flux density Bs and the core loss Pcv were obtained, and the results are shown in Table 6 below.

  As described above, the effects of the present invention are clear from the results of Experimental Examples I to VI.

  That is, according to the present invention, in the method for producing MnZn-based ferrite obtained by adding Li as a subcomponent to the main component of MnZn-based ferrite, the Li compound used for adding Li is insoluble in water. Since it is configured to be a hardly soluble compound, it is possible to suppress variation in characteristics between product lots, and to improve manufacturing yield and reliability of product quality.

  In addition, even when subcomponents are added when mixing the raw materials to be weighed, the Li compound is a compound that is insoluble or hardly soluble in water and a case that it is a compound that is not so soluble. Then, the difference of the effect similar to the experiment example was confirmed.

  The method for producing MnZn-based ferrite of the present invention can be widely used in various electric component industries.

Thirty raw data of the present invention I-1 sample and Comparative Example I-1 sample were plotted on a graph with Bs on the vertical axis and Pcv on the horizontal axis so that the level difference in characteristic variation could be visually recognized. Is.

Claims (9)

In the method for producing MnZn ferrite, in which Li is added as an accessory component to the main component of MnZn ferrite,
A method for producing a MnZn-based ferrite, characterized in that the Li compound used for adding Li is a compound that is insoluble or hardly soluble in water. The MnZn-based ferrite contains iron oxide as a main component in an amount of 54 to 60 mol% in terms of Fe ₂ O ₃ , zinc oxide in an amount of 3 to 10 mol% in terms of ZnO, and the remainder of manganese oxide (in terms of MnO). Item 2. A method for producing an MnZn ferrite according to Item 1. The Li compound is a Li ₂ CO ₃ terms, with respect to said main component, a method of manufacturing MnZn ferrite according to claim 1 or claim 2 is contained 0.1 to 0.8 wt%.   4. The MnZn-based ferrite according to claim 1, wherein the Li compound is an oxide containing Li and at least one component selected from Fe, Mn, and Zn. 5. Production method.   The method for producing a MnZn ferrite according to claim 4, wherein the Li compound is an oxide containing components of Li and Fe. The Li _{compound, LiFeO 2, LiFe 5 O 8} , Li 2 Fe 3 O 5, and a manufacturing method of the MnZn ferrite according to claim 5 Li ₅ is FeO least one selected from among _4.   The method for producing a MnZn-based ferrite according to claim 4, wherein the Li compound is an oxide containing components of Li and Mn. The method for producing an MnZn ferrite according to claim 7, wherein the Li compound is at least one selected from LiMn ₂ O ₄ and LiMnO ₂ .   Furthermore, at least 1 sort (s) selected from Si, Ca, Zr, Nb, Ta, V, Bi, Mo, and Sn is contained as a subsidiary component in any one of Claim 1 thru | or 8 contained. A method for producing MnZn-based ferrite.

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