JPS6021922B2 - Manufacturing method of Mn-Zn ferrite powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing Mh-Zn ferrite powder, and particularly to a method for producing Mh-Zn ferrite powder by a simplified manufacturing process.
nyFez) 0.Fe203 (however, 0.28SxSO.
8 0.1≦y≦0.6,0<zmi0.12,0. Spot S
xy<1) (hereinafter, Mn-Zn ferrite in the present invention refers to this composition.

) It is an object of the present invention to provide a method that makes it possible to efficiently obtain Mn-Zn ferrite powder consisting of: Additionally, Mn-Zn ferrite containing FeH as a solid solution has excellent electromagnetic properties as a material with particularly high magnetic permeability, and is commonly used in large quantities as a molded conjugate in the field of electronic devices. be.

The general manufacturing method for this product is Fe203, Mn○ and Z
The basic process is blending of n○ raw materials → mixing → preliminary molding → crushing → molding → main molding, and special techniques such as atmosphere control are applied especially in the main firing process. On the other hand, in recent years, kneaded bodies made of Mn--Zn ferrite powder and various binders have been molded and used for applications such as radio wave absorbers.

The Mh-Zn ferrite powder for this purpose is obtained by pulverizing an Mn-Zn ferrite molded mirror body obtained by the general production method submitted above using a powerful pulverizer for a long time. When obtaining Mn-Zn ferrite powder, the present inventor did not adopt the method of pulverizing the above-mentioned Mn-Zn ferrite molded compact, but considered obtaining Mn-Zn ferrite powder by a simpler manufacturing method. It's here.

That is, in the manufacturing process of the Mn-Zn ferrite molded sintered body, a relatively low temperature (temperature below the main firing temperature) is used to obtain a semi-ferrite powder that is convenient for moldability and main firing conditions.
However, the idea was to obtain Mn--Zn ferrite powder by performing these two steps of calcination in one step of high-temperature sintering. In this case, simply increasing the temperature of the subsequent calcination to a high temperature (same temperature as the main firing temperature) will cause the ferrite reaction to occur rapidly, resulting in the formation of Mn.
-The crystallinity and grain size of Zn ferrite crystal grains become non-uniform, and furthermore, Q-Fe203 precipitates due to oxidation of Fe in the ferrite composition during the cooling process after firing due to high temperature firing, which deteriorates electromagnetic properties. become. The inventor is M.
In producing n-Zn ferrite powder, one step of high-temperature firing promotes the crystallization of the produced crystal grains, suppresses bran formation between particles, and prevents oxidation of the Mn-Zn ferrite composition after firing. However, research has been conducted on methods that can perform cooling in the air.

In order to prevent oxidation of the Mh-Zn ferrite composition even if cooled in air and to prevent Q-Fe203 from precipitating, the crystallinity of the Mm-Zn ferrite crystal particles obtained by firing must be adjusted. fully developed, Mn-Zn
If the progress of oxidation of the ferrite composition is suppressed, q-Fe
They thought that it would be possible to suppress the precipitation of 203 to a minimum. In order to sufficiently develop the crystallinity of the Mn--Zn ferrite crystal particles, the firing temperature may be increased, but this causes strong crystallization between the particles, resulting in particle agglomerates that are difficult to crush. Therefore, the issue is a means to suppress formation of crystallization between particles under conditions that promote crystallization of crystal particles. As a result of conducting various studies on additives that are effective in suppressing coagulation between particles under conditions that promote the crystallization of Mn-Zn ferrite crystal particles, we found that SjQ, Nabui03, Ca
○, Bi203, and ZnB407 were found to be effective. As is clear from the phase diagram shown in Figure 1, oxidation during the cooling process of the high-temperature fired ingot occurs in the Mn-Zn ferrite fired at high temperature due to the relationship between the oxygen partial pressure of the atmosphere and the temperature. When cooled in air, it passes through a region where the spinel phase and Q-Fe203 phase coexist, and Q-Fe203 precipitates.

Figure 1 shows "Ferrite" Proceedings of the International Conference 1970 (FERR)
ITES: PrMeedin bag of thelnte
mationaI Conference,Julyl
970, Japan) p. It is described in 81 ~ spots, Fe203: 54.9 hol%, Mn○: 26
．． 8m. 1%, Zn○: 18.3 mol%, and the oxygen partial pressure in the atmosphere and the calcination temperature are changed. This is what I took.

Note that the hot line in the figure indicates the oxygen partial pressure in the air. As a conventional means to prevent the precipitation of Q-Fe203 due to oxidation during the cooling process described above, the atmosphere during cooling is set to an inert gas, such as a nitrogen gas atmosphere, and only the spinel phase shown in Fig. 1 is present. There are methods of cooling in a field or quenching in oil or water.

However, the former requires a large amount of inert gas;
The latter is also difficult to use industrially. Next, the present inventor found that in order to make the above-mentioned additives work more effectively and to facilitate pulverization, it is necessary to use a certain granulation mass of the raw material mixture during firing.

As a result of repeated studies based on the above-mentioned various findings, the present inventor has developed an Mn-Zn ferrite powder consisting of a single spinel phase in which q-Fe203 is not precipitated in the ferrite composition by one-step firing at high temperature. The present invention has been completed, which makes it possible to obtain the following.

That is, in the present invention, Fe203: 50 to 6 hol%, M
h○: 10-4 hol%, Zn○: 5-3 hol%
Sio2, Na2Si03, Ca
0.0, Bi203, ZnB407, one or more additives are added in an amount of 0.1 to 3.0% by weight based on the total raw material mixture, and granulated to a particle size of 2 to 3 mm, then 120
After firing at a temperature of 0 to 1350 qC, it is left to cool in the air to form (MnxZnyFez)0.Fe2Q (however, 0.28
≦x≦0.8, 0.1≦y≦0.6, 0<zSO. 12
,0. Obtaining a spinel single-phase composition with spots Sx<1),
Mn-Zn characterized by pulverizing this into powder
This is a method for producing ferrite powder.

Next, the configuration of the present invention will be explained in detail.

First, the composition of Mn--Zn ferrite powder, which is the object of the present invention, will be explained.

The Mn-Zn ferrite powder targeted by the present invention is (Mn
xZnyFez)0・Fe2Q (however, 0.28Sx≦0
．． &0.1≦y≦0.6,0<zmi0.12,0.8
It is made of a spinel single phase composition of 8Sxy<1). In particular, the solubility of Fen in the composition is important in terms of electromagnetic properties. In addition, the above-mentioned Fe is easily oxidized during the cooling process after high-temperature firing, and when oxidized, Q-F
It precipitates in the crystal as e203 and deteriorates the electromagnetic properties. In the present invention, by adopting the technical means detailed below, the precipitation of -Fe203 is eliminated, and the M
This is n-Zn ferrite powder. In addition, the mixing ratio of the raw materials to make the Mn-Zn ferrite powder with the above composition is Fe203:50~6 hol%, Mh0:10~
4 mark hol%, Zn0: 5 to 35 hol%, and the second
The ratio is within the range indicated by diagonal lines in the figure. If the blending ratio is within the above range, and Mn-Zn ferrite powder is obtained by firing, cooling, and pulverizing as described below, the composition (
M~Z-Fez) 0.28Sx in 0/Fe203
Mi0.8.0.1≦y≦0.0 0<zMi0.12,0
．． Mottling satisfies x+y<1. Next, the additives will be explained. In the present invention, Sio2, Na2Si03, and Ca are additives that have the effect of suppressing unwanted stripes between particles under conditions that promote crystallization of Mn-Zn ferrite crystal particles formed by high-temperature firing. ○, Bi203,
Zn&07 is mentioned.

These additives may be added alone or in amounts of 0.1 to 3. % by weight is added. When the amount added is less than 0.1% by weight, the effect of the addition is small, and the ferrite lump obtained by firing causes strong competition between particles, making it difficult to crush during powdering. On the other hand, the amount added is 3
．． Although it is possible to prevent competitive coalescence between particles when the weight percentage is more than . In addition, from the viewpoint of both the effect of preventing sintering between particles and the properties of the obtained Mn-Zn ferrite powder,
Industrially, it is preferable to add 0.5 to 1.5% by weight. In addition, the method of adding additives is not particularly limited,
It may be added by any method as long as it is homogeneously mixed with the raw materials at the time of blending the raw materials. Regarding the granulated particles, in the method of the present invention, the granulated particles need to have a length of 2 to 3 m. Even if the crystallinity of the Mh-Zn ferrite crystal particles is sufficiently developed, if the fired particle agglomeration is less than 2 ribs, the specific surface area is large, so when the high temperature fired particle souls are cooled in the air, they will not interact with the air. Excessive contact tends to promote oxidation, which is undesirable since there is a possibility that a large amount of Q-Fe203 will be precipitated. In addition, in the case of three or more ships, it is difficult to perform uniform firing, which is not appropriate. From an industrial standpoint, it is preferable that the granulated particles have a diameter of 5 to 2 mm. Regarding the competitive temperature, in the method of the present invention, the competitive temperature must be in the range of 1200 to 1350°C in air.

If the temperature is 1200°C or lower, it is difficult to form Subinel single-phase Mn-Zn ferrite.

This is because a temperature of 1200° C. or higher is required to sufficiently develop crystallinity to prevent oxidation during cooling. If it is 135 pi or more, decomposition of the Mn-Zn ferrite may occur, which is not preferable.

High temperature M generated by firing in the above firing temperature range
As already mentioned, the n-Zn ferrite particle mass can be cooled by letting it cool in the air.

Therefore, the step of cooling in an inert gas atmosphere such as nitrogen gas, which has been generally sought as a measure to prevent the oxidation of Fen in the Mm--Zn ferrite particle composition, is not required at all. The final pulverization is done according to the application, for example, processing conditions such as molding conditions of the kneaded body, and when used as a radio wave absorbing material, powder of an appropriate size is prepared according to the wavelength of the radio waves to be absorbed. In this case, there is no need for a particularly powerful pulverizer, and a normal pulverizer may be used.

Next, the effects of the method of the present invention having the configuration as described above will be described. According to the method of the present invention, only one step of high-temperature production is required, and cooling can be performed in air. Therefore, the manufacturing process can be extremely simplified compared to the conventional method for obtaining Mh-Zn ferrite powder. In theory, the obtained Mn-Zn ferrite powder is Q-Fe20
Almost no precipitation of No. 3 was observed, and it was a spinel single-phase product, which was equivalent to or better than the Mn-Zn ferrite powder obtained by re-pulverizing the molded compact obtained by the conventional method consisting of two-stage sintering. It has the electromagnetic properties of
The powder properties are also much better than those obtained by conventional methods. That is, the method of the present invention can obtain Mh-Zn ferrite powder with excellent properties through a simplified process, and is suitable for applications such as radio wave absorbing materials using a kneaded body with a binder. It has excellent industrial applicability, such as being able to supply Mn--Zn ferrite powder with excellent electromagnetic properties at low cost.

The present invention will be explained below with reference to Examples and Usage Examples.

Example 1 Fe203: 538 hol%, Mh.

A mixture of iron oxide, manganese oxide and zinc oxide with a mixing ratio of: 32.2 mol%, Z plate: 14.3 hol%, approximately 250% silicic anhydride, 20. Shelf (S■ corresponds to 0.0% by weight of the motherboard) was added, mixed for 20 minutes using a Lycay machine, and then granulated to obtain particles of 5 to 2 bays. Next, the above granulated particles were fired in the air in an electric furnace at 1300 qo for 3 hours (temperature increase: 200° C./hour). After firing, the product was taken out into the atmosphere, allowed to cool to room temperature, and then ground to an average particle size of 4.1 mm to obtain Mn--Zn ferrite powder. Obtained Mn-Zn
As a result of X-ray diffraction of the ferrite powder, a diffraction pattern showing only a spinel phase was obtained (see Figure 3). On the other hand, for the Mn-2n ferrite powder obtained under the same manufacturing conditions as above, except that no S treatment was added, a diffraction pattern showing the Subinel phase and the Q-Fe2Q phase was obtained as a result of X-ray diffraction. 4
(see figure).

Next, two female Mn-Zn ferrite powders obtained as described above were collected from each female, and 6% by weight of PVA was added.
(Polyvinyl alcohol) solution 1.5" was added, mixed well, and molded under pressure in a 25 mm mold to a height of 11.8 ribs. This was dried to form a cylindrical molded product. did.

The obtained cylindrical molded product was wound with a silk wire of 0.2 column J, and a magnetic field of looo e was applied using an electromagnet, and the saturation magnetic flux density (
As a result of measuring the following values, the following values were obtained. Sjo multi-addition 4 middle ls = my 8 auss/S
Example of 4vis=310 auss/2Fe203: 53.9hol%, Mn○: 27.
A mixture of iron oxide, manganese oxide, and zinc oxide with a blending ratio of 3 hol% and Zno: 18.8 mol%. Ship (equivalent to 0.5% by weight as Bi203).

) was added to form granulated particles of 5 to 2 lengths in the same manner as in Example 1, and then calcined at 1320° C. for 3 hours in the same manner as in Example 1. After firing, it was taken out into the atmosphere and allowed to cool to room temperature, and then ground to an average particle size of 1 to m to obtain Mn-Zn ferrite powder. As a result of X-ray diffraction, the obtained Mn-Zn ferrite powder was found to have only a spinel phase, similar to that bound in Example 1. On the other hand, the Mn-Zn ferrite powder obtained in the same manner as above without adding Bi2Q has a spinel phase and q-Fe20 as in Example 1 without the addition of Si.
It was confirmed that it showed three phases.

Next, one side of each of the Mn-Zn ferrite powders obtained as described above was taken, and 1 part of liquid phenol was added thereto and mixed well to obtain a gold powder with an outer diameter of 32.2 ◇ and an inner diameter of 19.3 ◇. The mixture was placed in a mold, pressure molded at 1 ton/ton, and then dried to obtain a ring-shaped molded product.

A wire winding of 0.2 ribs was wound around this, and the magnetic permeability was measured using an IKc bridge, and the following measured values were obtained.
Bi2〇Multi-Addition 1=45 Bi203 Bran Addition Mu=12 Example 3 A mixture of iron oxide, manganese oxide, and zinc oxide in the same proportion as Example 1 was mixed with 1.0 silicic anhydride (Sio2
This corresponds to 0.5% by weight.

) and 1.7 parts of calcium carbonate (corresponding to 0.5% by weight as Ca○) were added and mixed for 60 minutes using a Lykai machine. The above mixture was made into a molded granule of 25 skins x 10 skins, and fired in the same manner as in Example 1 at a temperature of 128 mm for 3 hours. After firing, it was taken out into the atmosphere and left to cool to room temperature, with an average particle size of 3. It was ground into a Mn-Zn ferrite powder. As a result of X-ray diffraction, the obtained Mn-Zn powder was found to have only a spinel phase, similar to the case of Example 1 in which Sio2 was added. On the other hand, in the Mn--Zn ferrite powder obtained under the same conditions as above without adding Sio2 and Ca○, a spinel phase and a Q-Fe203 phase were observed as a result of X-ray diffraction.

Usage Example The Mn-Zn ferrite powder obtained in Example 3 was kneaded into rubber at a weight ratio of 1:4.5.
As a result of measuring the transmission attenuation of 24 HZ radio waves, the following measured values were obtained.

Those with Si& and Ca○ added 1 Spot B Those without additives 11 Ship Example 4 X-ray diffraction results when Na2SiQ or Zn&07 was used as an additive and Mn-Zn ferrite powder was made in the same manner as in Example 1. As in Example 1, it was confirmed that it was a single spinel phase.

[Brief explanation of drawings]

Figure 1 shows Fe203: Mouse. ghol%, Mn○: 26.
It is a phase diagram showing a product when the oxygen partial pressure of the atmosphere and the calcination temperature are changed at a blending ratio of 8 hol% and ZNO: 18.3 hol%. Figure 2 shows the blending ratio of Fe203, Mn○ and Zn○ (m
It is a ternary system composition diagram showing ol%). 3 and 4 are X-ray diffraction diagrams, and FIG. 3 is an X-ray diffraction diagram of Sio
FIG. 4 is an X-ray diffraction diagram of Mh-Zn ferrite powder in the case of addition of Si and the like, and FIG. Tsutomu / Zutsutomu 2 Koji inferiority 3 * 4 side

Claims (1)

[Claims] 1 Fe_2O_3: 50 to 60 mol%, MnO: 1
Sio_2, Na_2SiO_3, Ca
One or more additives of O, Bi_2O_3, ZnB_4O_7 are added in an amount of 0.1 to 3.0% by weight based on the total raw material mixture, granulated to a particle size of 2 to 30 mm, and then granulated to a particle size of 1200 to 30 mm. After firing at a temperature of 1350°C, it was left to cool in the air to form (Mn_xZn_yFe_z)O・Fe_2O
_3 (However, 0.28≦x≦0.8, 0.1≦y≦0.6
, 0<Z≦0.12, 0.88≦x+y<1), and pulverizes the composition into powder. 2 The amount of additive added is 0.5 to 1 to the total raw material mixture.
．． Mn-Zn according to claim 1, which is 5% by weight.
Method for producing ferrite powder. 3 Claim 1 in which the granulated particle diameter is 5 to 20 mm
Or the manufacturing method of Mn-Zn ferrite powder according to 2.