JPH10144514A - Calcinated oxide powder, oxide magnetic material using it and their manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide oxide magnetic powder in narrow particle size distribution, an oxide magnetic material of high magnetic permeability and of low cost, and a method for manufacturing them. SOLUTION: To raw material powder, as a main component, comprising 20-30mol% manganese oxide (MnO), 20-30mol% zinc oxide (ZnO) and the other part of ferric oxide (Fe2 O3 ), bismuth oxide (Bi2 O3 ) of 0.05wt.% or less (not containing 0) is added as a sub-component, and they are calcinated at 600-1000 deg.C. Then in addition, zirconium oxide (ZrO2 ) of 0.04wt.% or less (not containing 0), chromium oxide (Cr2 O3 ) of 0.04wt.% of less (not containing 0), silicon oxide (SiO2 ) of 0.02wt.% or less (not containing 0) and calcium oxide (CaO) of 0.04wt.% or less (not containing 0) are added as sub-components, and they are mixed with binder, press-molded and burned, thereby a burned substance in which a value of standard deviation of crystal grain size divided by average crystal grain size is 55% or below is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an oxide calcined powder,
Oxide magnetic materials using them and their manufacturing methods, in detail, high permeability spinel type Mn-Zn based ferrite material mounted on a communication device, its manufacturing method and its calcined oxide powder, It relates to the manufacturing method.

[0002]

2. Description of the Related Art In recent years, with the demand for expansion and miniaturization of a frequency band due to noise regulations, a high-permeability oxide magnetic material applicable in a wide frequency band has been required.

In general, this type of oxide magnetic material contains, as a main component, 20 to 30 mol% of MnO and 20 to 30 mol%.
mol% of ZnO and the composition of the balance Fe ₂ O ₃ Mn-Zn
A system ferrite is used.

In order to obtain a high initial magnetic permeability μi in a Mn—Zn ferrite, it is necessary that the composition is uniform, the crystal grains of the fired body are uniform, the grain size is large, the density is high, and It is required that there are few pores in the body.

[0005] This Mn-Zn ferrite is usually obtained by weighing raw material powders of ferric oxide, manganese oxide, and zinc oxide.
After mixing, calcining, pulverizing, mixing with a binder (binder),
It is manufactured by press molding and firing.

[0006] Here, when the composition is made uniform and the crystal grains are made to be uniformly large by the firing step as described above, crystal grains accompanied by abnormal grain growth occur, and uniform structure control can be performed. Very difficult. Further, in order to increase the density and uniformly increase the crystal grains, 1300
It is fired at a temperature of 1400 ° C. When the binder is mixed, pressed and fired after the mixing step, the weight is reduced due to the thermal decomposition of the raw material, the volume is expanded due to gas generation, and the raw material powder as fine particles is fired. , Resulting in a product having problems such as cracks and deformation. Also,
Depending on the firing conditions, a certain degree of structure control is possible,
Complicating the firing conditions is inevitable, and the permeability cannot be fundamentally improved. In addition, complicated firing conditions require sufficient consideration in selecting a firing furnace, and also cause high costs.

Therefore, as a step prior to the sintering step, a method is employed in which calcination is performed once to homogenize and control the particle diameter of the powder as described above. The calcination is generally performed using a tunnel type electric furnace or a rotary kiln, etc.
It is performed in a temperature range of 1200 ° C. in the air or an inert atmosphere. It is generally known that the particle size distribution of the calcined powder is wide by observation with an electron microscope or the like. In such a calcined powder having a wide particle size distribution, it is difficult to control the structure of the fired body in the subsequent firing step, so that the crystal grain size cannot be uniformly increased, resulting in a decrease in magnetic permeability.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an oxide magnetic powder having a narrow particle size distribution, a low-cost oxide magnetic material having high magnetic permeability, and a method for producing the same using the same. .

[0009]

According to the present invention, the main component is 20%.
~ 30 mol% manganese oxide (MnO), 20-30
mol% of zinc oxide (ZnO) and the balance of ferric oxide (Fe
₂ O ₃₎ made of, as a subcomponent, an oxide calcined powder characterized by containing bismuth oxide of less 0.05 wt% (0 not including) (Bi ₂ O _3).

[0010] The present invention also relates to the present invention in which
0 mol% manganese oxide (MnO), 20 to 30 mo
1% zinc oxide (ZnO), with the balance being ferric oxide (Fe
The raw material powder becomes ₂ O _3), as a sub-component, 0.05 wt
% Or less was added bismuth oxide (not including 0) (Bi ₂ O _3), a method of manufacturing an oxide calcined powder, which comprises calcining at 600 to 1100 ° C..

In the present invention, the main component is 20 to 30 mo.
1% of manganese oxide (MnO), 20 to 30 mol% of zinc oxide (ZnO), and the balance of ferric oxide (Fe ₂ O ₃ ). Bismuth oxide (Bi ₂ O ₃ ), 0.04 wt% or less (excluding 0) of zirconium oxide (ZrO ₂ ), 0.0
4 wt% or less (excluding 0) of chromium oxide (Cr
₂ O ₃ ), characterized by containing 0.02 wt% or less (excluding 0) of silicon oxide (SiO ₂ ) and 0.04 wt% or less (excluding 0) of calcium oxide (CaO). It is a magnetic material.

The present invention also provides the above oxide magnetic material, wherein the value obtained by dividing the standard deviation σ of the crystal grain size by the average crystal grain size is 55% or less.

[0013] The present invention also relates to the present invention, in which
0 mol% manganese oxide (MnO), 20 to 30 mo
1% zinc oxide (ZnO), with the balance being ferric oxide (Fe
The raw material powder becomes ₂ O _3), as a sub-component, 0.05 wt
% (Not including 0) of bismuth oxide (Bi ₂ O ₃ ) and calcining at 600 to 1100 ° C., and further, as an auxiliary component, 0.04 wt% or less (excluding 0) of zirconium oxide (ZrO ₂ ), 0.04 wt% or less (excluding 0) of chromium oxide (Cr ₂ O ₃ ), 0.02 wt% or less (excluding 0) of silicon oxide (SiO ₂ ) and 0.04 wt%
% (Not including 0) of calcium oxide (CaO), a binder is mixed, press-molded, and fired.

The calcined oxide powder obtained according to the present invention comprises:
Regardless of the amount of powder to be processed, it is a powder with a uniform particle size and a narrow particle size distribution, so that even when fired at a high temperature, the structure of the fired body can be easily controlled and the crystal grains can be uniformly enlarged. And the density can be increased. Also,
Since the firing conditions can be simplified, the cost can be significantly reduced. Furthermore, ZrO ₂ , Cr ₂ O
₃ , the frequency characteristics of the initial magnetic permeability can be improved by adding a predetermined amount of each of SiO ₂ and CaO. Further, by containing these, the crystal grain size can be made uniform and the electric resistance of the grain boundary phase can be improved, so that the eddy current loss can be reduced.

In the present invention, MnO is 20 to 30 mo.
The reason for using 1%, ZnO of 20 to 30 mol%, and the balance of Fe ₂ O ₃ is that, other than in this region, the magnetic permeability decreases, which is not preferable.

The Bi ₂ O ₃ content is 0.05% by weight or less (0% by weight).
The reason is that μi sharply decreases when the value exceeds this range. This is considered to be caused by the hindrance of domain wall movement due to the increase in the number of vacancies or the distortion of crystal grains.

The ZrO ₂ content is 0.04 wt% or less (not including 0), the SiO ₂ content is 0.02 wt% or less (not including 0), and the CaO content is 0.04 wt% or less (including 0). The reason for this is that if it is within this range, a moderately high-resistance grain boundary phase is formed and eddy current loss is reduced, but beyond this range, the crystal grain size becomes extremely non-uniform, This is because the magnetic characteristics deteriorate.

Generally, it is said that Cr ₂ O ₃ forms a solid solution in the grains. The reason why the content of Cr ₂ O ₃ is 0.04 wt% or less (excluding 0) is that when the content is within this range, the wettability during firing is improved, the structure of the fired body can be homogenized, and the wettability can be further improved. By improving the properties, the degree of concentration of impurities in the grain boundary phase is improved and the amount of impurities in the grains is reduced, which has the effect of reducing eddy current loss. This is because magnetic properties are degraded.

In the present invention, the calcination temperature is set to 600
The reason for setting the temperature to １1100 ° C. is that if the temperature is lower than 600 ° C., the particle size distribution of the calcined oxide powder cannot be narrowed, and it becomes difficult to control the structure. If the temperature exceeds 1100 ° C., remarkable powder grain growth occurs, which not only takes time during pulverization in the subsequent step, but also broadens the particle size distribution of the powder, which makes it difficult to control the structure as described above. is there.

The reason why the value obtained by dividing the σ of the oxide magnetic material by the average crystal grain size of the oxide magnetic material is 55% or less is that, outside of this range, the magnetic permeability decreases,
This is because it is not preferable.

[0021]

As DETAILED DESCRIPTION OF THE INVENTION The main component, Fe ₂ O _3, Mn
O, a predetermined amount of Bi ₂ O ₃ is added as a sub-component to a raw material powder weighed to have a predetermined composition in terms of ZnO, mixed, calcined at a predetermined temperature, and further, as a sub-component,
Predetermined amounts of ZrO ₂ , Cr ₂ O ₃ , SiO ₂ , and CaO were added, and crushing, binder mixing, granulation, press molding, and firing were performed, and the value obtained by dividing the standard deviation of the crystal grain size by the average crystal grain size was obtained. 5
An oxide magnetic material having a content of 5% or less is obtained.

[0022]

Embodiments of the present invention will be described below.

(Example 1) The raw material powder was mixed with F as a main component.
e ₂ O ₃ , MnO, and ZnO are 52.6, 24.2,
It was weighed to 22.2 mol%, and B was
i ₂ O ₃ is 0.0, 0.01, 0.03, 0.05, 0.07 wt
%, And these were mixed and calcined at 900 ° C.

FIG. 1 shows the particle size distribution of the obtained calcined oxide powder. Than 1, which was calcined by adding Bi ₂ O ₃ is compared with those calcined without the addition of Bi ₂ O _3, it can be seen that the particle size distribution is narrow.

ZrO ₂ , Cr ₂ O was added to the calcined oxide powder.
₃ , SiO ₂ and CaO are 0.01 and 0.0, respectively.
2, 0.01 and 0.02% by weight, and these are crushed, granulated, and pressed by molding.
It was calcined at 0 at% or less at a temperature of 1100 to 1400 ° C. to obtain an oxide magnetic material.

FIG. 2 shows a change in the frequency characteristic of μi with respect to a change in the Bi ₂ O ₃ content in the obtained oxide magnetic material. 2, the content of Bi ₂ O ₃ is 0.05 wt%.
It can be seen that μi is degraded when it exceeds.

(Example 2) ZrO ₂ is contained as an auxiliary component in an amount of 0.0, 0.01, 0.02, 0.04, 0.06 wt%, Bi ₂ O ₃ , Cr ₂ O ₃ , SiO ₂ , CaO Was added in the same manner as in Example 1 except that the amounts were 0.02, 0.02, 0.01, and 0.02 wt%, respectively, to obtain an oxide magnetic material.

FIG. 3 shows a change in the frequency characteristic of μi with respect to a change in the ZrO ₂ content in the obtained oxide magnetic material. According to FIG. 3, when the ZrO ₂ content is 0.04 wt% or less (excluding 0), preferably, 0.01 to 0.02.
It can be seen that in the case of wt%, the frequency characteristics of μi are good.

(Example 3) Cr ₂ O ₃ is contained as an auxiliary component in an amount of 0.01, 0.02, 0.04, 0.06 wt%, Bi ₂ O ₃ , ZrO ₂ , SiO ₂ , CaO Was added in the same manner as in Example 1 except that the amounts were 0.02, 0.01, 0.01, and 0.02 wt%, respectively, to obtain an oxide magnetic material.

FIG. 4 shows the change in the frequency characteristic of μi with respect to the change in the Cr ₂ O ₃ content in the obtained oxide magnetic material. According to FIG. 4, when the content of Cr ₂ O ₃ is 0.04 wt% or less (excluding 0), the content is preferably 0.01 to 0.0.
It can be seen that the frequency characteristics of μi are good in the case of 2 wt%.

(Example 4) As subcomponents, SiO ₂ is contained in an amount of 0.01, 0.01, 0.02, 0.04 wt%, and Bi ₂ O
₃ , ZrO ₂ , Cr ₂ O ₃ , and CaO are 0.02 and 0.2, respectively.
An oxide magnetic material was obtained in the same manner as in Example 1, except that the addition was performed so as to be 0.01, 0.02, and 0.02 wt%.

FIG. 5 shows the change in the frequency characteristic of μi with respect to the change in the SiO ₂ content in the obtained oxide magnetic material. According to FIG. 5, when the SiO ₂ content is 0.02 wt% or less (not including 0), preferably, the content is 0.01 to 0.02.
It can be seen that in the case of wt%, the frequency characteristics of μi are good.

(Example 5) CaO is 0 as a subcomponent,
0.01, 0.02, 0.04, 0.06 wt%, and B
i ₂ O ₃ , ZrO ₂ , Cr ₂ O ₃ and SiO ₂ are each 0.0
An oxide magnetic material was obtained in the same manner as in Example 1, except that the addition was performed so as to be 2, 0.01, 0.02, and 0.01 wt%.

FIG. 6 shows a change in the frequency characteristic of μi with respect to a change in the CaO content in the obtained oxide magnetic material. According to FIG. 6, when the CaO content is 0.04% by weight or less (excluding 0), preferably 0.01 to 0.02.
It can be seen that in the case of wt%, the frequency characteristics of μi are good.

(Example 6) Bi ₂ O ₃ , Z
Each of rO ₂ , Cr ₂ O ₃ , SiO ₂ and CaO is 0.0.
2, and 0.01, 0.02, 0.01, and 0.02 wt%, except that the calcination temperature was changed in the range of 500 to 1200 ° C. every 100 ° C. Similarly, an oxide magnetic material was obtained.

FIG. 7 shows the relationship of μi at 10 kHz to the calcining temperature in the obtained oxide magnetic material. From FIG. 7, when the calcination temperature is 600 to 1100 ° C., μi
It can be seen that the characteristics are good.

Example 7 Bi ₂ O ₃ , Z
Each of rO ₂ , Cr ₂ O ₃ , SiO ₂ and CaO is 0.0.
Oxide magnetic material was prepared in the same manner as in Example 1 except that it was added in an amount of 2, 0.01, 0.02, 0.01, and 0.02 wt%, and the oxygen partial pressure and the firing temperature were changed. I got

FIG. 8 shows the relationship of μi at 10 kHz to the value of σ / average crystal grain size in the obtained oxide magnetic material. FIG. 8 shows that the μi characteristic is good when the value of σ / average crystal grain size is 55% or less, preferably 45% or less.

[0039]

According to the present invention, it is possible to provide an oxide magnetic powder having a narrow particle size distribution, a low-cost oxide magnetic material having high magnetic permeability and a method for producing the same using the same. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a change in particle size distribution with respect to a change in Bi ₂ O ₃ content in a calcined oxide powder of Example 1.

FIG. 2 is a diagram showing a change in μi frequency characteristic with respect to a change in Bi ₂ O ₃ content in the oxide magnetic material of Example 1.

FIG. 3 is a diagram showing a change in frequency characteristics of μi with respect to a change in ZrO ₂ content in the oxide magnetic material of Example 2.

FIG. 4 is a diagram showing a change in μi frequency characteristic with respect to a change in Cr ₂ O ₃ content in the oxide magnetic material of Example 3.

FIG. 5 is a diagram showing a change in μi frequency characteristic with respect to a change in SiO ₂ content in the oxide magnetic material of Example 4.

FIG. 6 is a diagram showing a change in the frequency characteristic of μi with respect to a change in the CaO content in the oxide magnetic material of Example 5.

FIG. 7 is a graph showing the relationship between the calcination temperature and μi at 10 kHz in the oxide magnetic material of Example 6.

FIG. 8 is a graph showing the relationship between σ / average crystal grain size and μi at 10 kHz in the oxide magnetic material of Example 7.

[Explanation of symbols]

1 Bi ₂ O ₃ content 0 wt% 2 Bi ₂ O ₃ content 0.01 wt% 3 Bi ₂ O ₃ content 0.03 wt% 4 Bi ₂ O ₃ content 0.05 wt% 5 Bi ₂ O ₃ content 0 0.07 wt% 11 ZrO ₂ content, Cr ₂ O ₃ content, SiO ₂ content, or CaO content 0 wt% 12 ZrO ₂ content, Cr ₂ O ₃ content, SiO ₂ content, or CaO content 0 0.01 wt% 13 ZrO ₂ content, Cr ₂ O ₃ content, SiO ₂ content, or CaO content 0.02 wt% 14 ZrO ₂ content, Cr ₂ O ₃ content, SiO ₂ content, or CaO content The amount 0.04 wt% 15 ZrO ₂ content, Cr ₂ O ₃ content, SiO ₂ content, or CaO content 0.06 wt%

Claims (5)

[Claims] A manganese oxide (MnO) containing 20 to 30 mol% of a main component and a zinc oxide (Zn) containing 20 to 30 mol% of a main component.
O), the balance being ferric oxide (Fe ₂ O ₃ ), characterized in that it contains 0.05% by weight or less (not including 0) of bismuth oxide (Bi ₂ O ₃ ) as an auxiliary component. Calcium powder. 2. A sub-component is added to a raw material powder which is composed of 20 to 30 mol% of manganese oxide (MnO), 20 to 30 mol% of zinc oxide (ZnO), and the balance of ferric oxide (Fe ₂ O ₃ ) as a main component. Of bismuth oxide (Bi ₂ O ₃ ) of 0.05 wt% or less (not including 0)
A method for producing a calcined oxide powder, comprising calcining at 100 ° C. 3. A manganese oxide (MnO) containing 20 to 30 mol% of a main component and a zinc oxide (Zn) containing 20 to 30 mol% of a main component.
O) with the balance being ferric oxide (Fe ₂ O ₃ ), with bismuth oxide (Bi ₂ O ₃ ) of 0.05 wt% or less (not including 0) and 0.04 wt% or less (0 Zirconium oxide (ZrO ₂ ), not more than 0.04 wt% (0
Chromium oxide (Cr ₂ O ₃ ), 0.02 wt%
The following (not including 0) silicon oxide (SiO ₂ ) and 0.04
Calcium oxide (CaO) of wt% or less (excluding 0)
An oxide magnetic material comprising: 4. The oxide magnetic material according to claim 3, wherein the value obtained by dividing the standard deviation of the crystal grain size by the average crystal grain size is 55% or less. 5. A raw material powder comprising _{20 to 30} mol% of manganese oxide (MnO), 20 to 30 mol% of zinc oxide (ZnO) and the balance of ferric oxide (Fe ₂ O ₃ ) as a main component, Of bismuth oxide (Bi ₂ O ₃ ) of 0.05 wt% or less (not including 0)
After calcination at 100 ° C., 0.04
wt% or less (excluding 0) of zirconium oxide (ZrO
₂ ), chromium oxide (Cr ₂ O ₃ ) of 0.04 wt% or less (excluding 0), silicon oxide (SiO ₂ ) of 0.02 wt% or less (excluding 0) and 0.04 wt% or less (0 (2) excluding calcium oxide (CaO), mixing a binder, press molding, and firing.