JPH02263406A - Oxide magnetic material powder and manufacture thereof - Google Patents

Abstract

PURPOSE:To enable the high coercive force and the highly saturated magnetization to be obtained by a method wherein Al2O3 is substituted for a part of the material Fe2O3 of Ba and Sr base magnetoplumbite type ferrite in specific composition. CONSTITUTION:A material powder is mixed, dried up and baked so that the material powder may be composed meeting the requirement of 0.2<=x<=4.0 when 0<=a<0.05 and 0.1<=x<=4.0 when 0.05<=a<=1.0 in the expression of (1-a) BaO.aSrO(6-n-x)Fe2O3Al2O3 (n=0-1.5). In the material blending process, the value of x(Al2O3) is specified to be 0.2<=x<=4.0 since the coercive force of Ba ferrite powder (when a=0) exceeds the objective value, if x exceeds 0.2 likewise if x does not exceeds 4.0 the saturated magnetization exceeds the same. Furthermore, when SrO is substituted for a part of BaO (a=0), similar characteristics can be displayed so far as a <0.05 but within the range of 0.05<=a<=1.0 the coercive force exceeds the objective value if x exceeds 0.1 likewise the saturated magnetization exceeds the same if x does not exceed 4.0. Through these procedures, the coercive force and the saturated magnetization can be augmented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic material powder, and more particularly to a magnetoblanbite-type oxide magnetic material powder having a high coercive force and a method for producing the same.

[Prior Art] Magnetic materials are generally used in many cases by utilizing high magnetic flux density. However, coercive force is often used primarily. In particular, when the coercive force (, He) is large, there is an advantage that it can be made thinner very easily.

In particular, in a magnet containing a polymer resin, it is possible to easily form an extremely thin magnetic layer by bonding magnetic material powder with a polymer resin, etc., so having a high coercive force is
There are advantages.

In addition, in this method of forming polymer resin and magnetic material powder, the space factor of the magnetic powder is lower than that of sintered bodies, etc.
Although it has the disadvantage of reduced magnetization, it is flexible and can be easily manufactured even with complex shapes, and can be made into thin strips by rolling or by coating. 'j'j film formation can also be easily implemented.

On the other hand, processing a sintered body with good precision at a thickness of 1 inch or less requires extremely advanced technology, and processing at a thickness of 100 μm or less is extremely difficult.However, in these thickness regions,
This is an extremely easy field in the field of polymer composite magnetic materials.

On the other hand, as the thickness of magnetic materials progresses, the demagnetizing field increases, and materials with low coercive force have a phenomenon in which their properties as magnetic materials decrease and eventually cease to function.

Therefore, in order to reduce the thickness of a magnetic material, a magnetic material having a high coercive force is useful.

Currently, Sm-C is a magnetic material with high coercive force.
Rare earth magnet materials such as o series, Nd-Fe-B series, Pt-C
There are intermetallic compound materials such as O type and Pt-Fe type magnets, but these have poor pulverizability and are difficult to obtain powder with a uniform particle size distribution when used as magnetic powder. , it's also expensive.

Furthermore, since rare earth magnet materials are chemically active, if they are used in powdered form, oxidation causes changes over time, such as deterioration of magnetic properties.

In contrast, magnetobrambite-type ferrite magnets (
M-type ferrite, general formula MO・6Fe2O3, where M
are Ba, Sr, Pb, etc.) are generally raw material powders (e.g., BaCO3,5rCO,, Fe2 o3.Fe0
OH, Ag2O,.

It is obtained by mixing AΩ (OH)3 and the like and then firing at a temperature of about 800° C. or higher, and is inexpensive and chemically stable since it is a oxide.

[Problems to be Solved by the Invention] However, the coercive force of this magnetoblanbite type ferrite magnet is clearly lower than that of the above-mentioned intermetallic compound magnet.

For example, the characteristics of sintered magnets currently on the market are B r
It is around 4.2kG, +Hc 3 koe.

In addition, this oxide magnet has good pulverization properties, but when crushed to an average particle size of around 1 μm, the IHc is 1 koe.
Decrease back and forth.

Therefore, the first technical problem of the present invention is to improve the coercive force of magnetoblanbite ferrite such as stable barium-based and strontium-based ferrite materials at low cost, and to improve the coercive force of oxide magnetic material powder having high coercive force. An object of the present invention is to provide a method for manufacturing the same.

Furthermore, in order to obtain a high IHC, - part of Fe2O is replaced with A
When replacing with N 2 O 3 etc., Hc increases with the amount of substitution, but the temperature at which magnetobrambite ferrite is formed also increases by 1, so it is necessary to sinter at a high temperature to form magnetobrambite ferrite 111 phase. become.

However, in the high temperature range, even a slight increase in temperature causes significant sintering of the powder. Therefore, in order to obtain a high coercive force magnetic material that is fine and has a narrow particle size distribution, it is extremely useful to lower the firing temperature.

Generally, a method of lowering the firing temperature is to mix a small amount of additives. The reason for this is that when this type of additive is added in a large amount, it diffuses into the magnetoblanbite type ferrite and significantly increases both magnetization and coercive force.

On the other hand, it is not easy to uniformly mix small amounts of additives, and it can be said to be a particularly difficult method. Therefore, if there are additives or substituents that can be mixed in large quantities, it will be very useful industrially since it will be possible to tolerate some degree of mixing variation.

Therefore, the second technical problem of the present invention is to provide an oxide magnetic material powder which is inexpensive and has a high coercive force and whose coercive force is improved by mixing a large amount of substituent under the stable magnetobrambite ferrite. The object of the present invention is to provide a manufacturing method thereof.

In addition, ZnO is added to magnetobrambite-type ferrite powder.
In compounds consisting of ZnO as one of the main components, ZnO
As the content of W-type ferrite is increased, W-type ferrite tends to be generated more easily.

Therefore, in order to form the 11-phase magnetoblanbite-type ferrite, restrictions arise in terms of composition and firing temperature. Therefore, a manufacturing method that can reduce these manufacturing constraints will be extremely useful in industry.

Therefore, the third technical problem of the present invention is to produce an oxide magnetic material with high coercive force in which part of the Fe2O3 of magnetobrambite ferrite is replaced with AR2O3, under a wide range of manufacturing conditions, with similar magnetic properties (+Hc). An object of the present invention is to provide an oxide magnetic material powder having a high coercive force and a method for producing the same.

[Means for Solving the Problems] According to the present invention, the general formula (1-a) BaO・asro
・(6-n-x)Fe2O3-, xAl2O3:
(However, when n-0~L, 5.0≦a<0.05, 0
．． 0 when 2≦x≦3.0, 0.05≦a≦1.0,
An oxide magnetic material powder is obtained which is characterized by having a chemical composition expressed as (1≦x≦3.0).

According to the present invention, the general formula (1-a) BaO.asro
-(6-n-x-y-z)Fe2O3xA, Q2O3
eyZnO*zTi02: (However, n -0
~1.5.0≦y≦1.0.0≦Z≦t, o, CI.

0 when 1≦y+z≦1.3 and 0≦a<0.05
．． 2≦x≦3.0.1 when 0.05≦a≦1.0
An oxide magnetic material powder characterized by having a chemical composition expressed by ≦x≦3.0) is obtained.

According to the present invention, the general formula (1-a) BaO.asro
・(6-n-x)Fe2O.・xAl2O,=
(However, when n-0 to 1.5, 0.2≦x≦3.OSo when 0≦a<0.05, 0 when 05≦a≦1.0
．． In the method of manufacturing oxide magnetic material powder by mixing raw material powders so as to have a chemical composition expressed as 1≦x≦3.0), drying, and firing in a firing atmosphere, Ag2O3
A method for producing oxide magnetic material powder is obtained, characterized in that the average particle size of the raw material powder is 0.005 to 1.0 μm.

According to the present invention, there is obtained the method for producing oxide magnetic material powder, wherein the firing atmosphere contains 50 vol% or more of oxygen.

According to the present invention, the general formula (1-a) BaO.asrO
(6-n-x-y-z)Fe2O3XAR2Oi
・yZnO-zTio2: (However, n-0 to 1
．． 5.0≦y≦1.0, 0≦z≦1.0.0.1≦y
When +z≦1.3 and 0≦a<0.05, 0.2≦x
≦3.0, (0.1≦x when 1.05≦a≦1.0
In a method of manufacturing oxide magnetic material powder by mixing raw material powders so as to have a chemical composition expressed by ≦3.0), drying, and firing in a firing atmosphere, the average particle size of Au2O3 raw material A method for producing an oxide magnetic material powder characterized in that the powder has a diameter of 0.005 to 1.0 μm is obtained.

According to the present invention, there is obtained the method for producing oxide magnetic material powder, wherein the firing atmosphere contains 50 vol% or more of oxygen.

Magnetobrambite barium type (hereinafter abbreviated as M-type Ba) ferrite has the general formula BaO・6Fe2Oi
However, the region where high magnetic properties can be obtained is BaO・(6-,n)Fe2O3 (where n
-0 to about 1.5).

In addition, as a magnetic material, the value indicating the characteristics of high coercive force is +Hc 5 K Oe or more, the amount of magnetization is 4π engineering, and 0.
．． The condition was that the powder satisfy a value of 5KG or more. Then, replacing a part of Fe2Q3 with A112O3 becomes even more useful, and BaO・(6-n-x)F
It was found that x-0,L~3.0 is an effective range for e2O3 .xAil 2O3.

On the other hand, magnetobrambite-type strontium (hereinafter M
Type Sr) type ferrite also has the general formula Sr0.
6Fe2C), but as a magnetic material, IHc is approximately 5 koe as a value indicating the characteristics of high coercive force.
As mentioned above, if the magnetization amount satisfies a value of about 0.5 KG or more at 4πIs, part of Fe2O3 can be replaced with Ag2O.
, it becomes even more useful to substitute with SrO・(
6-n-x) Fe2O3 ・xA92O3 x -0
, 1 to 3.0 was found to be an effective range.

Furthermore, as a result of various experiments, the present inventor has found that the characteristic values of the above magnetic powder are (1) (1-a) BaO conflict aSrO conflict (6-n
-X) F e2O3 ” XAI 2O3 :
(where n-〇~1.5), 0≦g<Q, 05,
0.2≦x≦3.0.

(2) (1-a) BaO-aSrO・ (6-n
x) F e2O3 aXAN 2O3 (where n
-0~1. ．． 5) Medium, 0,05≦a<1.0,0.1≦
Let x≦3.0.

(3) The average particle size of the Al2O3 raw material powder is 0.005
It has been discovered that this can be achieved by setting the thickness to 1.0 μm.

In the above (1), the value of X (AJII2O.) is set to 0.
The reason for setting 2≦x≦3.0 is that Ba ferrite powder (a-
0), IHC is 5KOe or more when x-0.2 or more, and 4πIs is 0.5KG when x-3.0 or less.
This is because the above is the case.

Furthermore, when a part of BaO is replaced with SrO (when a≠0), similar characteristics can be obtained up to a<0.05. However, when 0.05≦a≦1.0,
As shown in (2) above, X(AN 2O3 )<0
．． Even if it is 2, if 0.1≦x, IHC is 5KO
If it is more than e and less than x-3,0, 4π15 will be more than 0.5KG, and of course a-1.0, that is, even if BaO is all SrO, IHC will be more than 5KOe and 4πIs will be 0.5KG.
The above characteristics can be obtained.

In addition, the average particle size of the Al2O3 raw material powder is set to 0.005~
The reason why it is set in the range of 1.0 μm is that if it is less than 1.0 μm, the reactivity improves and the formation of M-type ferrite becomes noticeable.
This is because Hc values exceeding 5KOe can be obtained, and 0.
The reason for setting the particle size to be 0.005μ1 or more is that in addition to confirming the particle size within this range in the present invention, it is currently difficult to industrially use powder with a particle size smaller than this, which would cause inconveniences in terms of cost and work. be.

However, with this substitution of Ag2O3, IH
Although C is improved, the temperature at which the M-type ferrite single phase is formed also increases, and the tendency for the magnetic properties of the ferrite powder to change depending on the firing temperature becomes remarkable.

Therefore, if there is a method that lowers the firing temperature, shows similar magnetic properties over a wide firing temperature range, and can be expected to increase 4π1s compared to the decrease in 4πI5 due to Al2O3 substitution, A high coercive force M-type ferrite powder with small variations and high magnetic properties can be easily produced, which is extremely useful industrially.

As a result of various experiments, the present inventor has found that by substituting a part of the above composition with ZnO, TiO2, etc., an M-type ferrite having high coercive force and similar magnetic properties can be obtained over a wide firing range. , and that it can also be expected to improve saturation magnetization.

The chemical composition ratio of one type of M-type ferrite is (1-a)
BaO-aSrO・(6-n-x-yz) F
e2O3 number XAg 2O.・yZnOII
zTiO□: (where n=0 to 1.5.a-0-0
,05, x=0.2~3.0, a-0,05~1, x-0, 1~0.3, z-0,
It is useful in the range of 1 to 1.0.

Here, the ranges of n, a, and
This is because the amount of change in the magnetic properties of the powder due to the sintering process is clearly reduced at z-0.1 or more. Also, at y-0, z-
The reason for setting it below 1.0 is that if the content exceeds I
The formation of a different phase (Y-type ferrite) with low HC was observed,
This is because, depending on the firing temperature, a clear decrease in IHc is observed.

On the other hand, the ranges of n, a, and X are the same as above, and 2=0
, when y≠0, the chemical composition ratio is (1-a) BaO-aS
rO・(6-n-x-y-z)Fe2O3・xAN
2O3...yZnO・zTiO2; (here,
n-0 to 1. 5. x-0 when a-0 to 0.05
, 2~3.0, a-0, when 05~1, x-0, 1~0
．． 3, it is useful in the range of y-0.1 to 1.0.

Here, the ranges of n, a, and
This is because when the temperature is 1 or more, the temperature at which M-type ferrite is formed is clearly lowered.

The reason why y is set to 0.1 or less is that if the content exceeds this value, the formation of a different phase (W type ferrite) with low IHC is observed, resulting in a significant decrease in IHc.

Furthermore, M-type ferrite containing both ZnO and TiO2 has a chemical composition (1-a) BaO・asro-3r
O・(6-n-x-y-z)Fe2O3 ・XAg2
O3...yZnO.zTiO.

(Here, when n-0 to 1.5, a=o to 0.05, x-0, 2 to 3.0, a-0, and when 05 to 1°0, x
-0, 1 to 3.0, and furthermore, y≠0゜2≠0, y+z=
0.1 to 1.3) is useful.

Here, the ranges of n, a, and x are based on the same reason as mentioned above, and the reason why y≠O and z≠0 is ZnO, TiO
This is because the effect is more pronounced when 2 is contained in combination than when 2 is contained alone.

The reason why y+z is limited to within the range of 0.1 to 1.3 is that when y+z is 0.1 or more, the amount of change in the magnetic properties of the powder due to the sintering temperature is clearly reduced, and the 4πI is also improved. This is because you can expect it.

On the other hand, the reason why y+z is set to 1.3 or less is that if the content exceeds this value, W-type ferrite will be generated and coexisted during firing in a high temperature range, resulting in a decrease in IHC and stable magnetic properties over a wide firing temperature range. This is because it becomes difficult to obtain.

Furthermore, the effect of containing ZnO and TiO2 in combination is more pronounced than when using them alone because the coexistence of Zn2+ and Ti'+ approaches M3+ and stabilizes the formation of M-type ferrite. I surmise that this is for the purpose of further improvement.

Moreover, such S ro-F e2O, -Ag2O3
Even if it is a ZnOTiO2 based M-based ferrite,
When the content of ZnO increases significantly, the temperature increases from 12O0℃ to 130℃.
When fired in air at around 0° C., a W phase is generated, making it difficult to obtain a powder exhibiting homogeneous magnetic properties.

In order to solve this problem of coarse W formation in the M phase, the inventor conducted repeated experiments and determined that the oxygen content in the firing atmosphere was reduced to 5.
It has been discovered that by setting the VOI% in the range of 0 to 100 %, the generation of W phase during firing can be suppressed, and ferrite powder of M phase and t11 phase, particularly Sr-based ferrite, can be obtained.

The reason why this oxygen content is set to be within the range of 50 to 100 vat% is that the oxygen content of the firing atmosphere is 50v.

% or less, the atmosphere becomes reducing for the fired powder, and W
We speculate that this is because phase formation cannot be suppressed.

[Example] Embodiments of the present invention will be described with reference to the drawings.

Example 1゜Purity is 99.5vt% or more, average particle size is 0.5um
The following a-Fe2O3. BaC0, and the average particle size is 0.
005,0.01.0.05゜0, 10. 0. 5
0. 1. 0. 3. 0. 5. α-A of 0μm
Using I12O3, the chemical composition ratio is Ba0・5.3Fe
Each was weighed to give 2O3 .0.5AN2O3. Next, these eight types of powder were mixed using a ball mill for 20 hours using ethanol as a dispersion medium, dried, and then held at 1000° C. in the atmosphere for 2 hours to produce a fired powder. After crushing these fired powders in a mortar, powder X-ray diffraction and coercive force measurements were performed.

Unreacted material (α-F e 2O3 +
α-AN2O3) and reaction product (M-type Ba ferrite), and coercive force (+Hc) using a vibrating magnetometer.
was measured.

The results are shown in Table 1.

The coercive force (+Hc) was determined by a vibrating magnetometer with a maximum applied magnetic field of 30 KOe.

From Table 1, the average particle size of the AN2O3 raw material powder is 0.00.
In the samples of 5 to 1.0 μm, there were no unreacted substances, and values exceeding those of powder were obtained.

The following margin C also contains 5KOe in Example 2゜The purity is 99.5vt% or more and the average particle diameter is 0.2am.
The following a-Fe2O3. Using BaCO3 and α-Al2O3 with an average grain size of 0.2 μm, the chemical composition ratio is B.
aO・(5,5-x)Fe2O3・xAl2O. (Here, x-0,0,2,0°5.1.0,1.5,2.
0, 2.5, 3.0), respectively.

Next, these eight kinds of powders were mixed and dried in the same manner as in Example 1, and then fired at 800 to 1000°C in 50°C increments.

After crushing these calcined powders for 3 hours using a ball mill with ethanol as a dispersion medium, the reaction products were confirmed by X-ray diffraction.
Saturation magnetization (4πIs) and coercive force (+
Hc) was determined as Apl, and the results are shown in FIG.

The reaction product was confirmed by powder X-ray diffraction, and it was confirmed that there were no unreacted substances in the M-type crystal compound.

Furthermore, these powders were observed to have a narrow submicron particle size distribution using a scanning electron microscope.

In addition, in FIG. 1, curve 11 is 4π■8 at each concentration of AR2O3 measured by a vibrating magnetometer, and curve 12 is +I( at each concentration of Al2O3 measured by a vibrating magnetometer).
c.

The high coercive force oxide magnetic material according to Example 2 is BaO・(5
, 5-x) Fe2O3.xAl2O3. From Fig. 1, IHc of 5KOe or more is obtained when x=0.2 or more, while 4πIs of 500G or more is obtained by x-3
, 0 or less.

Therefore, it can be seen how many rounds the value of X is within the range of x-0, 2 to 3.0.

Example 3゜Similarly to Example 2, the chemical composition ratio was (1-a) BaO・aSro・5.5Fe2O゜−0,
1A112O3 (here a-0,0,1°0.2,0
．． 5, 0.7, 0.9, 1.0), weigh,
Mixed and dried.

Next, these seven types of powders were held at 900° C. for 10 hours in the air to produce fired powders. These powders were crushed for 5 hours using a ball mill using ethanol as a dispersion medium, and then dried. It was confirmed by X-ray diffraction that these powders were only a single compound with a magnetobrambite crystal structure.

FIG. 2 shows (a) saturation magnetization (4πIs) and (b) coercive force (I
HC) and the ratio of each 5 rOia degrees, and shows the results of measuring the powder obtained by the above method using a vibrating magnetometer in the same manner as in Example 1.2.

In FIG. 2, curve 21 is 4πI5 and curve 22 is I
HC respectively, and the high coercive force oxide magnetic material according to Example 3 is (1-a) BaO-asro-5,5
Fe2O3 Red 0° IAl2O3.

As shown in this figure, for 5KOe or more, Ho is a −0,
Achieved in the area of 0.05 or higher.

a-1.0 is an Sr-based ferrite containing no BaO.

SrO is useful for increasing Hc within the range of 0.05≦a≦1.0.

Moreover, 4π1s hardly changes with respect to the value of a.

Example 4゜Purity is 99.5 wt% or more, average particle size is 0゜5μm
The following a Fe2 o,, S rcOi and the average particle size are 0.005, 0.01.0.05, 0°10.0.
50. Using α-8 to 2O3 of 1.0, 3.0, 5.0 μm, the chemical composition ratio is Sr0.5, 3 Fe 2O
3" 0.5AJ72O3, respectively.

Next, these eight types of powder were mixed for 20 hours using a ball mill with ethanol as a dispersion medium, and after drying,
This was held at 1000° C. for 2 hours in the air to produce a fired powder.

Next, after crushing these calcined powders in a mortar, unreacted substances (α-Fe2O., α-AN2O.
3) and the reaction product (magnetobrambite type Sr ferrite), and a vibrating magnetometer (maximum applied magnetic field of 30
Coercive force (IHC) was measured by Ke).

The results are shown in Table 2.

There was no unreacted sample in which the average particle size of the AR2Oi raw material powder was 0.005 to 1.0, and the IHC value of the powder exceeded 5 KOe.

Below margin Example 5, purity is 99.5wt% or more, average particle diameter is 0°2tt
m or less a-Fe2O. , S rco, and the average particle size is
Using 0.2 μm α-Ag2O3, the chemical composition ratio is S.
rO・(5,5-x)Fe2O3-xA,Q2O3
: (X is 0.0.2.0.5°1.0, 1.5, 2.
0, 2.5, 3.0).

Next, these eight kinds of powders were mixed and dried in the same manner as in Example 4, and then fired at 900 to 1400°C in 50°C increments.

Next, ethanol was mixed using a ball mill for 20 hours, and the calcined powder was crushed for 3 hours, and the reaction products were confirmed by X-ray diffraction. For the powder fired at low temperature, the saturation magnetization (4πIs) and coercive force (+Hc) were measured using a vibrating magnetometer (maximum applied magnetic field 30KOe) using AI!
I decided.

The results are shown in FIG.

IHC of 5 KOe or more is obtained at x-0,1 or more.

On the other hand, 4πls of 500G or more is obtained at x-2.5 or less. From these facts, it can be seen that a value of X in the range of 0.1 to 3.0 is useful.

Furthermore, these powders were observed to have a narrow submicron particle size distribution using a scanning electron microscope.

Example 6 Purity is 99.8vt% or more and average particle size is 0.2μm
The following a Fe 2O3, S r CO3, α-
Using Ag2O3, the chemical composition ratio is SrO・(3,5Y
)Fe2Oi'2AN2O3・yZnO (where y-
0, 0, 1.0, 5° 1.0).

Next, these eight types of powders were mixed for 20 hours using a ball mill with ethanol as a dispersion medium, dried, and then held in the air at 900°C to 1150°C for 1 hour at 50°C intervals to form the calcined powder. Created. Next, after crushing these powders in a mortar, unreacted substances (α-F
e2O3 ・αAN2Oi) and the reaction product (M-type Sr
ferrite).

The results are shown in Table 3.

Here, in Table 3, O indicates only M-type Sr ferrite, △ indicates α-Ag2O3 remains, × indicates α-Fe2O3 and α-A
This shows that both g2O3 remains. From the results in Table 3, it can be seen that the degree of calcination IH is clearly reduced by ZnO substitution of 0.1 or more.

In addition, the magnetic properties (4
π■3, +Hc) using a vibrating magnetometer (maximum applied magnetic field 30k)
Oe).

The results are shown in Table 4.

From the results shown in Table 4, it can be seen that substitution of ZnO tends to slightly improve 4πIs and slightly decrease IHc.

However, even at y-1.0, 1Hc is 9.5
koe, and is a magnetic powder with extremely high coercive force.

Example 7 In the same manner as in Example 6, the chemical composition ratio was SrO・(5,2
-y) F e2Oi ・0. 5 ・A(12O3・
yZnO (here x-0,0,2,0,4°0.6,0
．． 8, 1.0, 1.2), respectively.
After mixing and drying, the mixture was held at 1100° C. for 10 hours and fired.

Next, after crushing these powders, the magnetic properties (4πIs, +Hc) were determined using a vibrating magnetometer.

The results are shown in FIG.

In FIG. 4, in the region where the amount of ZnO substitution is 0<y>1.0, 4πI5 is slightly improved, and IHC shows a tendency to decrease, but has a high value.

On the other hand, in the region of y>1.0, there is a significant improvement in 4πI,
A decrease in IHC is observed, and high coercive force magnetic powder cannot be obtained.

When we investigated the formation phase of these powders by X-ray diffraction, we found that
When y was O~1.0, it was a single phase of M-type Sr ferrite, but a large amount of W-type ferrite was mixed in the powder of y-1.2.

Furthermore, these powders were observed to have a narrow submicron particle size distribution using a scanning electron microscope.

Example 8 Purity is 99.8 wt% or more and average particle size is 0.2 μm
The following a-Fe2O3. S rco,.

a-Al2O], the chemical composition ratio is Sr0.5,
5-x-z) Fe2O7 ・xAj72O3 ・zT
iO2 (where x-1 is z-0,05 and X-1.5
The samples were weighed to give three compositions (z-0).

Next, these powders were mixed using a ball mill for 20 hours using ethanol as a dispersion medium, and after drying,
A sintered powder was produced by holding the temperature in the air at 50°C for 2 hours in the range of 1050°C to 1350°C.

Next, after crushing these powders in a mortar, unreacted substances (S ro ·a-F e2O3 ) were determined by X-ray diffraction.

It was confirmed that M-type Sr-based ferrite was generated without the presence of α-AN 2 O3 , T i 02 ).

When these powders were observed using a scanning electron microscope, they were found to consist of crystal grains of about 1 μm or less.

Next, the magnetic properties (4πI5°+Hc) of these powders were measured using a vibrating magnetometer (maximum applied magnetic field 30 koe).

The results are shown in FIG.

From this result, it was found that by substituting TiO□, S
It can be seen that r-type ferrite powder can be obtained.

Therefore, TiO in M-type Sr-based ferrite powder
It can be seen that the substitution of 2 allows the production of powders with -like magnetic properties over a wide range of calcination temperatures.

Example 9 In the same manner as in Example 8, the chemical composition ratio was SrO・(5,2
z) Fe2O3 φ0.5ΔI2OszTi02 (
Here z-0,02,0,4゜0.6,0.8,1.0
, 1.2), mixed, dried, and held at 50°C for 5 hours in the range of 1000'C to 1300°C to produce a fired powder.

Next, these powders were crushed in a mortar and then subjected to X-ray diffraction.
Although Sr-type ferrite was produced, it was confirmed that Y-type ferrite was mixed in z-1.2. When these powders were observed using a scanning electron microscope, they were found to consist of crystal grains of about 1 μm or less.

Next, the magnetic properties (4πIS++Hc) of these powders were measured using a vibrating magnetometer (maximum applied magnetic field 30 kOe).
1J was determined. The results are shown in FIG. In the figure, 4πI5
．． , Ho is the median value of the maximum and minimum values of the measured values for each composition, Δ4π15+ ΔIH
C represents the difference between the maximum value and the minimum value. Up to z=1.0, due to TiO2 substitution, Δ4πIS+ Δ1Ho
shows a tendency to decrease significantly, but at z = 1.2, 4πl
s, the decrease in IHC and the increase in 4πIS+Δ1Hc became remarkable.

Therefore, TiO in M-type Sr-based ferrite powder
It can be said that the substitution effect of 2 is significant in the range of x-0.1 to 1.0.

Example 10 Purity is 99.8 wt% or more and average particle diameter is 0°2
a-Fe2O3 below μn. SrCO3,aA,Q2
O3. Using ZnO and TiO2, the chemical composition ratio is SrO
・(3,5-y-z)Fe203-2Al2O.
War y ZnO fist z TiO2: (Here y and 2 are 0
．． y is 0.5 and Z is 0. Three types of compositions were weighed so that y was 0.5 and 2 was 0.3).

Next, these powders were mixed using a ball mill for 20 hours using ethanol as a dispersion medium, dried, and then held in the air at 950°C to 1130°C for 1 hour at 50°C increments to produce fired powders. did.

Next, after crushing these powders in a mortar, unreacted substances (α-Fe2O., α-A12O3) were determined by X-ray diffraction.
and reaction products (M-type S "ferrite and other hexagonal ferrites") were confirmed.

The results are shown in Table 5.

Table 5 below shows the powder magnetic properties of each composition fired at 1150°C (4π
Is, +Hc) using a vibrating magnetometer (maximum applied magnetic field 30 k
Oe) was determined as all+.

The results are shown in Table 6.

In Table 6, O is M type S "ferrite only, △ is α-A12O.
remains, × is a-Fe2Q, and α-A12O. Both remain, indicating that M-type Sr ferrite and W-type ferrite coexist.

From the above results, by containing zno and TiO2 in combination, it is clear that the firing temperature is lowered and the M
It can be seen that the temperature range in which only the Sr type ferrite single phase is formed is expanded.

From the above results, it can be seen that zHc decreases slightly by ZnO substitution, but 4πIs improves, and even if TiO2 is substituted, the magnetic properties do not decrease.

Therefore, S ro-F e2O3 AN 2O3
By including TiO2 in a part of the M-type sr ferrite based on the -ZnO system, the reaction formation temperature is lowered and the single t0 formation temperature range is expanded without deterioration of the magnetic properties.

Example 11 In the same manner as in Example, the chemical composition ratio was SrO・(4,5-
y z) Fe2O3 ・AD 2O3 ・yZnO−
zTio2 (where y and 2 are 0, y is O and 2 is 0
．． 5. After weighing the three compositions so that y is 0.3 and 2 is 0.5), they are mixed, dried, and heated to 1000℃~1
The temperature was maintained at 50° C. for 5 hours within a range of 250° C. to produce a fired powder.

Next, after crushing these powders in a mortar, unreacted substances (SrOaα-Fe2O3, a AN2
O. , ZnO, Ti02) were not present, and it was confirmed that M-type Sr-based ferrite was produced.

Furthermore, when these powders were observed using a scanning electron microscope, they were found to consist of crystal grains of 1 μm or less.

Next, the magnetic properties of these powders (4πI s , IH
c) was determined by a vibrating magnetometer.

The results are shown in FIG.

From this result, it is clear that ZnO and Ti are present in a part of the Sr-based ferrite.
It can be seen that by containing O2, a powder with stable magnetic properties over a wide firing temperature range and a high 4πI5 can be obtained.

Example 12 In the same manner as in Example 10, the chemical composition ratio was 5rO (5,2
-y-z)Fe2o3-Ag2O3yZnOazT1
02 (here y-2, y+z-0,02,0,4
, 0, 6, 0, 8° 1.0, 1.2, 1.4), mixed, dried, and heated at 950°C to 1.
The temperature was maintained at 50° C. for 10 hours within a range of 250° C. to produce a fired powder.

Next, after crushing these powders in a mortar, X-ray diffraction revealed that they were M-type Sr-based ferrite single phase in the range of y+z=0 to 1.2, but the powders with y+z=1.4 It was confirmed that a small amount of W-phase ferrite was present in the powder fired at 1250°C.

When these powders were observed using a scanning electron microscope, they were found to consist of crystal grains of about 1.5 μl or less.

Next, the magnetic properties (4πI5°Hc) of these powders were measured using a vibrating magnetometer.

The results are shown in FIG.

In the figure, 4π■S+ IHC is the median value of the maximum and minimum values of the measured values for each composition, Δ4π■s,
ΔIHc represents the difference between the maximum value and the minimum value. z+
In the range of y-0,1 to 1.3, Δ4πIS+Δ1
A significant decrease in Ho was observed, indicating that Sr-based ferrite powder with stable magnetic properties could be obtained over a wide firing temperature range. Moreover, while maintaining high IHC, 4π■
s has also increased significantly.

Example 13 A-Fe2O. with a purity of 99.8 wt% or more and an average particle size of 0.2 μl or less. ．． 5rCO,, a-Ag2O3 =
Using Z n O* T I O2, the chemical composition ratio is S ro #3.8 F e2O3 ”0.5 AN
2O3 "0.7Zn0・0.7TiO2 was weighed, mixed and dried, heated to 1230℃ with air atmosphere, and 02/(02+N2) was 30.40.50.6
The powder was adjusted to 0.80° and 100 voρ% and held for 5 hours to obtain a fired powder.

Note that the flow rate of this atmosphere was 1 Ω/min.

Next, after crushing these powders in a mortar, the formed phase was confirmed by X-ray diffraction.

Further, the magnetic properties (4πIs, IHc) of the powder were determined by applying a magnetic field of about 30 koe using a vibrating magnetometer.

The results are shown in Table 7.

When these powders were observed with a scanning electron microscope, it was found that 1
Most of the particles were ~1.5 μm.

As described above, when 02 in the firing atmosphere is 50 vol% or more, W-type ferrite, which is a different phase, disappears, and IHC is significantly improved.

In addition, in the examples, as the raw material powder of ferrite,
BaCO3,5rC03,a-Fe2O,,a-Ag2
O3. Although only the case where ZnO and TiO2 are used has been described, the present invention also relates to the case where ZnO, -Ag2O. ,
BaO-5r.

-Fe2O3-Ag2O3. S ro-Fe2O3-A
g2O. , S ro-Fe2O3-Ag2O3-ZnO
,BaO-Fe2O,-All 2O゜ZnO,S r
o-Fe2O. -AN2O3-ZnOTiO2,Ba
Any M-type ferrite containing OFe2O*A112Ox-ZnO-TiO2 as a main component can be applied.

On the other hand, the raw material powder is also Bad, Ba(OH)2BaSO
4, Sr (OH)2. SrO, SrCΩ2+ 5r
SO,,,a-Fe2O0H,Fe(OH)3.7-F
e2Os, AJII (OH)3ZnCO3, Z
nTi (SO4)2, Ti (SO4)
In the second firing step, BaO-Fe2O.

Ag2O. , Ba0-S rO-Fe2O3AJ72O
．． , S rO-Fe2O. -Al2O. .

S ro F e2 03 -Ail 2 0
3-ZnO, BaO-Fe2O. -AI 2O. −
ZnO, BaO-3ro-Fe2Oi-AN
2 03 -ZnO, S rOFe2 0* A
f! 2 03 TiO2, Ba0-F e2 0
3-AI203-T i02, Ba
0-S ro-Fe2 03-An 2 0s-T
i02,. 5ro-Fe2O. -AI 2O. -Zn
O-TiO2, BaOF e2Os-AX)2 03
-ZnO-TiO2, BaO-3rO-Fe2O. -A
It is easily understood that any reaction that produces N2Q3-ZnO-TiO2 or the like is included in the present invention from the ferrite production reaction.

In addition to the manufacturing method of the present invention, in which raw material powders are mixed and then fired, methods for manufacturing magnetobrambite-type ferrite powder include a coprecipitation method, an organometallic salt method, a vitrification precipitation method, etc. The manufacturing method of the former two types is essentially the same as that of the present invention since compound crystals are generated by firing.

Furthermore, those skilled in the art will understand that the vitrification precipitation method is considered a part of the present invention if the composition of the crystallized ferrite powder is included in the present invention.

[Effects of the Invention] As described above, according to the present invention, the coercive force of the magnetobrambite type ferrite made of Sr-based ferrite material is reduced by replacing a part of this ferrite with Ag2O3. Accordingly, it is possible to provide an oxide magnetic material powder that can be reformed and has a high coercive force, and a method for producing the same.

Further, according to the present invention, it is inexpensive and stable.

and Sr-based ferrite material Fe2O, a part of which is ANzO
M-type ferrite material substituted with x is replaced with ZnO and TiO
By appropriately adding at least one type of □, it is possible to manufacture the material to exhibit constant magnetic properties over a wide firing temperature range, and an improvement in the magnetic properties (4πIs) can also be expected.

According to the present invention, by containing 50 vol% or more of oxygen in the firing atmosphere in which the raw material powder is fired, the coercive force of the stable magnetobrambite ferrite can be improved at low cost, and the magnetic material has a high coercive force. A method for producing a powder can be provided. In particular, among magnetobrambite ferrites, a part of Fe2O is replaced with Ag2O,
Magnetobrambite-type ferrite (M-type ferrite) materials substituted with can be manufactured over a wide manufacturing range so as to exhibit similar magnetic properties.

[Brief explanation of drawings]

FIG. 1(a) shows M-type Ba ferrite BaOφ (5,5-x)Fe2O3·xAl2O according to Example 2 of the present invention.
FIG. 1(b) is a diagram showing the relationship between the content of All 2O3 in No. 3 and the saturation magnetization (4πIs), and FIG.
O3・xA, p 2O. A diagram showing the relationship between Al)2Os content and coercive force (IHC), FIG.
・aSrO・5.5Fe2O3 "O, A diagram showing the relationship between the S"O content and the saturation magnetization (4πIs) of IAl2O3, FIG. 2(b) is the M type B a according to Example 3 of the present invention.
7 Elite (1-a) BaO-aSrO-5,5F
e2O3・Q, SrO content and coercive force of IAl2O3 (
Figure 3 is a diagram showing the relationship between A and IHC) of the magnetobrambite type strontium ferrite in Example 5.
I2O3 content and saturation magnetization of ferrite powder (4π
FIG. 4 is a diagram showing the relationship between the Sr-based ferrite (SrO・(5
,2-y)Fe2Oa -0,5Aj)2O3 ・
yZno) is a diagram showing the relationship between ZnO-containing ff1(y), saturation magnetization (4πIs) and coercive force (IHC) of ferrite powder. FIG. 5 shows the Sr-based ferrite (5,5-x-
z) Fe2O. - In the raw material mixture composition of xAl2O3zTi02 (here, 3 compositions of z-0.05 at x-1 and z w-Q at x-1.5), the firing temperature and magnetic properties of the powder (4π■S+Hc) In the figure, the O mark (solid line) indicates the composition of zmo at x-1.0, and the 0 mark (-
The dotted line) represents the composition of Z-0 at X-1.5, and the Δ mark (dotted line) represents the composition of Z-0.5 at X-1.0. FIG. 6 shows the Sr-based ferrite)SrO・(
5,2-z) Fe2O3 ・0.5 Ag2O3・z
T l 02 (here, z=0.0.2゜0,
4. 0. 6. 0. 8. 1. 0. 1. 2
) About the raw material mixture composition, 1000 ° C ~ 1
Median value 4πIs of the maximum and minimum magnetic properties (4πIs. IHC) of powders fired in the range of 300°C. 1Hc and its difference Δ4πIs, ΔIHo and Ti
A diagram showing the relationship with O2 substitution value 2, FIG. 7 is Example 10
Sr-based ferrite (4,5-y-z) F
e2 o 3 *AJ7 □ 03 *
In the raw material mixture composition of yZnOezTiO2, 11
This is a diagram showing the relationship between the sintering temperature and magnetic properties (4πIs, IHC) of powders sintered in the range of 00 to 1300°C.
In the figure, the O mark (solid line) indicates the composition where y and 2 are 0, and the 0 mark (-
The dashed dotted line) represents a composition in which y is 0 and 2 is 0.5, and the △ mark (dotted line) represents a composition in which y is 0.3 and 2 is 0.5. FIG. 8 shows the Sr-based ferrite SrO・(
5,2-y-z)Fe2 030.5Ajl'2O3
・VZnO-zTi02 (here, y=-z, y+z-0,0,2,0,4°0.6,0.8,1
．． 0, 1.2, 1.4), 9
50. The median value of the maximum and minimum values of the magnetic properties (4πI, Hc) of the powder fired in the range of °C to 125 °C is 4π■s. IHC and its difference Δ4π'Sr Δ IHC and Zn
FIG. 3 is a diagram showing the relationship between O and TiO2 content (y + z). Collection [Fig.
3-YZnOy (Z, 0) Figure 5 Jumping temperature ('C) Figure 7 SrO (4,5'j-Z) Fe2,03. AM2O3 So ZTLO 7 pieces, ○2 temperature (0C) Fig. 6 5rC) (5,2-Z) FezO30,5A4zO3
TLO2 Z (TiO2) SrC) (5,2-Gokun8 Figure Z) Fe2O30.5Ak03 ZrLO・l T
LO2 (Tatashishi = Z) (Kun ÷ Z) Procedural Amendment (Voluntary) Date of January, 2008

Claims (6)

[Claims] 1. General formula, (1-a) BaO・aSrO・(6-n-
x) Fe_2O_3・xAl_2O_3: (However, n=
0 to 1.5, and when 0≦a<0.05, 0.2≦x≦3
．． 0, 0.1≦x≦3.0 when 0.05≦a≦1.0
) An oxide magnetic material powder characterized by having a chemical composition represented by: 2. General formula, (1-a) BaO・aSrO・(6-n-
x-y-z) Fe_2O_3・xAl_2O_3・yZ
nO・zTiO_2: (however, n=0 to 1.5, 0≦y
≦1.0, 0≦z≦1.0, 0.1≦y+z≦1.3, and when 0≦a<0.05, 0.2≦x≦3.0, 0.0
An oxide magnetic material powder characterized by having a chemical composition expressed as (0.1≦x≦3.0 when 5≦a≦1.0). 3. General formula, (1-a) BaO・aSrO・(6-n-
x) Fe_2O_3・xAl_2O_3: (However, n=
0 to 1.5, and when 0≦a<0.05, 0.2≦x≦3
．． 0, 0.1≦x≦3.0 when 0.05≦a≦1.0
) The raw material powders are mixed to have the chemical composition expressed by
A method of producing an oxide magnetic material powder by drying and firing in a firing atmosphere, characterized in that the average particle size of the Al_2O_3 raw material powder is 0.005 to 1.0 μm. Production method. 4. 4. The method for producing oxide magnetic material powder according to claim 3, wherein the firing atmosphere contains 50 vol% or more of oxygen. 5. General formula, (1-a) BaO・aSrO・(6-n-
x-y-z) Fe_2O_3・xAl_2O_3・yZ
nO・zTiO_2: (however, n=0 to 1.5, 0≦y
≦1.0, 0≦z≦1.0, 0.1≦y+z≦1.3, and when 0≦a<0.05, 0.2≦x≦3.0, 0.0
When 5≦a≦1.0, 0.1≦x≦3.0), the raw material powders are mixed so as to have a chemical composition expressed as 0.1≦x≦3.0), dried, and fired in a firing atmosphere to produce an oxide magnetic material. In the method for producing powder, the average particle size of the Al_2O_3 raw material powder is set to 0.
0.005 to 1.0 μm. A method for producing an oxide magnetic material powder. 6. 5. The method for producing a high coercive force oxide magnetic material according to claim 5, wherein the firing atmosphere contains 50 vol% or more of oxygen.