JPS5950072A - Oxide magnetic material and manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oxide magnetic material having improved magnetic permeability and temperature coefficient of magnetic loss of manganese zinc ferrite, and a method for manufacturing the same.

Manganese zinc ferrite has a wide range of uses as a magnetic material for magnetic heads and communication equipment, and its properties have been improved to suit each application, resulting in materials with excellent properties.
It is still in a state of rapid progress.

Such materials are often used especially in erasing heads of tape recorders, and important characteristics for erasing heads include high density, low magnetic loss, and small changes in temperature characteristics of magnetic permeability and magnetic loss. It is better that the magnetic rate is as high as possible.

As a method to obtain a material with low magnetic loss, CaO and 5in2
A method of increasing electrical resistance by adding a combination of is well known (Japanese Patent Publication No. 36-2283). This method is certainly effective, but when the sintering temperature is raised to increase the density of the material, an abnormal sintering reaction occurs, and the sintered structure becomes a mixture of small and large crystals. Therefore, there was a problem in that magnetic loss characteristics tend to deteriorate.

Next, as a method to reduce the temperature characteristic change of magnetic permeability, C
There is a method of adding oo or Co2O3. However, none of the known techniques has been able to sufficiently reduce the change in temperature characteristics of magnetic loss.

In view of the above-mentioned current situation, this invention has been developed to prevent abnormal sintered structure even at high sintering temperatures, to reduce magnetic loss, and to reduce magnetic permeability.
With the aim of creating an oxide magnetic material with small temperature characteristic changes in magnetic loss, various experiments have shown that CaO and Coo are the basic components of ZTI-based ferrite.

7. An oxide magnetic material with extremely good properties can be obtained by adding rOH or a combination of CaO, Coo, and VzOs and controlling the oxygen concentration in the cooling atmosphere after sintering, or by hot isostatic pressing. I found out that.

That is, this invention has a basic composition consisting of 50 to 56 mol% of iron oxide, 21 to 38 mol% of manganese oxide, and 6 to 25 mol% of zinc oxide, and calcium oxide o, oi to 0.1w.
t%, cobalt oxide 0.05 to 0.15 wt%, zirconium oxide 0.02 to 0.1 wt%, or vanadium oxide 0.02 to 0.1 wt%, with low magnetic loss and magnetic permeability. It is an oxide magnetic material with excellent properties at the temperature of magnetic loss and magnetic loss. This is a method for producing an oxide magnetic material, the gist of which is hydrostatic molding.

-6800/ T+b I < 100 P < -4
300/T+b Also, T: temperature (°C), P: oxygen concentration (%), bl, bl: constant set to match the oxygen concentration during sintering.

The basic components of t'tn-Zη ferrite include CaO and C.
o.

When 5LOe is added in addition to the above, when it is made into a high density material,
Although it tends to become an abnormal crystal structure, 7. instead of si and oe.
When r02 or v205 is added, a magnetic material with a uniform crystal structure, high electrical resistance, and low magnetic loss can be obtained even when it is made into a high-density material. Furthermore, in the conventional sintering method, C is added to the basic component of t'tn-zη ferrite.
When Zroe or 205 is added in combination in addition to aO and CoO, the temperature characteristic of magnetic permeability is small, but the temperature change in magnetic loss becomes large. On the other hand, if the cooling atmosphere after sintering is made more oxidizing than the equilibrium oxygen pressure, the temperature change in magnetic loss becomes smaller. In addition, by further hot isostatic pressing, magnetic permeability and magnetic loss can be
It is possible to increase the density without damaging the I characteristics.

Next, the reason for limiting the composition of the oxide magnetic material according to the present invention will be explained.

The reason for using 50 to 56 mol% of iron oxide, 21 to 38 mol% of manganese oxide, and 6 to 25 mol% of zinc oxide is because other compositions have extremely low magnetic permeability and are not practical as soft magnetic materials. be.

Calcium oxide has an electrical resistance of 10 Ω-α or less when it is contained in an unvortexed state, making it impossible to maintain low magnetic loss characteristics, and when it exceeds 0.01 wt%, it tends to form an abnormal crystal structure, which again results in low magnetic loss characteristics. Since it cannot be obtained, 0.0
The content is 1 to 0.1 wt%.

Cobalt oxide is less effective in reducing the temperature coefficient of magnetic permeability if it is contained less than 0.15 wt%.
If it exceeds 0.05, the magnetic permeability itself decreases.
The content is 0.15 wt%.

As mentioned above, zirconium oxide or vanadium oxide is added to greatly increase electrical resistance and reduce magnetic loss, and when both are added at 0.0'2wt% without vortex, they have the effect of increasing electrical resistance. is small, and 0.1wt
If the addition exceeds 0.02 to 0.1 wt%, the magnetic permeability decreases in the case of zirconium oxide, and an abnormal crystal structure tends to occur in the case of vanadium oxide.

Next, the reason why the oxygen concentration (P%) at the time of cooling after sintering the oxide having the above composition is set to a concentration that satisfies the following formula will be explained.

-6800/ T+b I < log P < -4
300/ T+b Soup stock, T; Temperature ("C), P:
Oxygen concentration (%), b+, b2: Constant set to J: which corresponds to the oxygen concentration during sintering.

When log p≦−6800/T b +, the temperature coefficient of magnetic loss is the same as the result obtained by the conventional method;
When p≧−4300/T + b 2, the deterioration of magnetic permeability increases, so the oxygen concentration P% is set to satisfy the above formula.

By the way, to explain the relationship between the sintering conditions and the above constants,
When sintering is carried out in nitrogen containing 1% oxygen at a sintering temperature of 1250°C, b I = 3.44, b 2 = 5.44
, and when sintering is performed in nitrogen containing 2% oxygen at a sintering temperature of 1250°C, b 1 = 3.74, b 2 =
5.74, and when sintering is carried out in nitrogen containing 0.5% oxygen at a sintering temperature of 1200°C, b, -=3.14, b2
-5.14.

Further, in this invention, when performing hot isostatic pressing, -
The oxygen concentration during cooling after the next sintering is logp--4300/T+3.44 within the area surrounded by curve B in the graph, which shows no relationship between the cooling temperature and oxygen concentration in Figure 1.
It is preferable to cool along the curve D (T=1250°C). This is because the sintered body is reduced to some extent during hot isostatic pressing. In addition, in FIG. 1, A is the equilibrium oxygen concentration curve, and B is 10(] P = -6800/T+5
．． 44 (T=1250°C), C is the cooling condition in Examples 2 and 3.

Examples according to the present invention will be described below.

[Example 1] Fe2O353.5 mol%, MnC0a 32.5 mol%, and Zn014 mol% were weighed, wet mixed using a ball mill using pure water as a dispersion medium, and dried at 850°C.

Preliminary sintering was performed for 3 hours. Next, predetermined amounts of additives shown in Table 1 were added to this, and the mixture was again pulverized using a ball mill.

After crushing, add binder to 9mmφX 5mmφX
A ring sample with a size of 3 mm was formed, sintered in nitrogen containing 1% oxygen at 1250°C for 3 hours, and cooled in a furnace at the equilibrium oxygen concentration shown by line A in Figure 1.

The magnetic permeability, relative magnetic loss coefficient, and electrical resistance of each sample obtained are shown in Table 1, and the temperature characteristics of magnetic permeability are shown in FIG. In addition, correction addition of the main component was performed at the time of pulverization so that the secondary peak temperature of magnetic permeability was almost the same for each sample.

As is clear from Table 1 and Figure 2, samples a and c
Comparing the above, it can be seen that the temperature coefficient of magnetic permeability is improved by the addition of Coo, but the sample with S=O, c, has an abnormal crystal structure at a relatively high sintering temperature of 1250 °C. , and the magnetic loss is deteriorating.

In contrast, trial 1'11.2.3 in which Zy Op was added
In the case of 8-, the electrical resistance is high as in the case of adding Sl, and moreover, the magnetic loss is small without forming an abnormal crystal structure. However, the hot water coefficient characteristics of magnetic loss are not very good because cooling after sintering is performed at equilibrium oxygen concentration. Note that the symbols in the figure and the sample numbers match.

[Example 2] The sintered bodies of Sample a and Sample 2 obtained in Example 1 were cooled at an oxygen concentration of line C, which is within the range of the present invention, as shown in FIG. Cooling treatment was also performed at 81 degrees. The temperature characteristics of the magnetic loss of each sample are shown in the dimensional graph of the relationship between temperature and relative loss coefficient in FIG. Note that the symbols and sample numbers in the figure match, the solid line is for the equilibrium oxygen concentration treatment, and the chain line is for the treatment of the present invention. As is clear from the results, it can be seen that the temperature characteristics of magnetic loss of the samples produced by the method of this invention are significantly improved compared to those produced by the conventional method.

[Example 3] Fe2O354.5 mol%, 11nO37.3 mol%,
ZTIO was weighed to be 8.2 mol%, wet mixed using a ball mill using pure water as a dispersion medium, and after drying,
0℃.

Preliminary sintering was performed for 3 hours. Then, predetermined amounts of additives shown in Table 2 were added to this, and the mixture was again pulverized using a ball mill.

After crushing, add binder to 9mmφX 5mmφX
It was molded into a ring sample with a size of 3 mmj, sintered in nitrogen containing 1% oxygen at 1250°C for 3 hours, and cooled with oxygen mW at line C, which is within the range of this invention as shown in FIG.
Cooling treatment was also performed at the conventional equilibrium oxygen concentration.

The magnetic permeability, relative magnetic loss coefficient, and electrical resistance of each sample obtained are shown in Table 2, the temperature characteristics of magnetic permeability are shown in FIG. 4, and the temperature characteristics of magnetic loss are shown in FIG. In addition, correction addition of the main component was performed at the time of pulverization so that the secondary peak temperature of magnetic permeability was almost the same for each sample. Note that the reference numerals and sample numbers in the figure match, the solid line is for the equilibrium oxygen concentration treatment, and the chain line 11- is for the treatment of the present invention.

As is clear from the results, by adding 50.1% of V2O, the electrical resistance becomes 150Ω-■, and no abnormal crystal structure occurs at all. In addition, the effect of Coo's magnetic permeability on the temperature characteristics is clear, and it can be seen that oxygen concentration control during cooling plays an important role in improving the temperature characteristics of magnetic loss.

Margin below 12- [Example 4] Fe2O354.0 mol%, Mn0 36.0 mol%, Z
Weighed so that nO was 10.0 mol%, wet mixed using a ball mill using pure water as a dispersion medium, and after drying,
℃.

Preliminary sintering was performed for 3 hours. Next, predetermined amounts of additives shown in Table 3 were added thereto, and the mixture was again pulverized using a ball mill.

After crushing, add binder to 9mmφX 5mmφX
A ring sample with a size of 3 mmt was formed and sintered at 1200°C for 3 hours in nitrogen containing 0.8% oxygen to obtain a log P--4300/T13.
The sample was cooled at 5-line oxygen concentration, and the sample was sintered at 1250°C for 3 hours in nitrogen containing 1% oxygen.
Cooling treatment was also performed at the conventional equilibrium oxygen concentration.

Furthermore, the obtained sintered body was heated at 1100°C and 900k.
Hot isostatic pressing was carried out under the condition of q4° argon atmosphere.

FIG. 6 shows the temperature characteristics of magnetic loss of each sample obtained.

In addition, correction addition of the main component was performed at the time of pulverization so that the secondary peak temperature of magnetic permeability was almost the same for each sample.

Note that the symbols in the figure and trial number 1 match, the solid line is for the equilibrium oxygen concentration treatment, and the chain line is for the treatment of the present invention.

It is clear from FIG. 6 that the method of this invention densifies the magnetic material and improves the temperature characteristics of magnetic loss.

Table 3 15-

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between cooling temperature and oxygen concentration. FIG. 2 and FIG. 4 are graphs showing the temperature characteristics of magnetic permeability, respectively. Example 3. The characteristics of the sample obtained in Example 4 are shown. FIG. 3, FIG. 5, and FIG. 6 are graphs showing the temperature characteristics of magnetic loss, respectively. Example 3. Example 4
The characteristics of the sample obtained are shown below. Applicant: Sumitomo Special Metals Co., Ltd.
1/L /rtIJ"4141澾n?'g4-4'4日子376-±)Ryoha

Claims (1)

[Claims] 1. Iron oxide 50-56 mol%, manganese oxide 21-38 mol%
mol%, basic composition consisting of 6 to 25 mol% zinc oxide,
Calcium oxide 0.01-0.1 wt%, cobalt oxide 0.05-0.15 wt% and zirconium oxide 0.02
~o, iwt% or vanadium oxide 0.02-0.1w
An oxide magnetic material with low magnetic loss and excellent temperature characteristics of magnetic permeability and magnetic loss, characterized by containing t%. 2 Iron oxide 50-56 mol%, manganese oxide 21-38
mol%, basic composition consisting of 6 to 25 mol% zinc oxide,
Calcium oxide 0.01-0.1 wt%, cobalt oxide 0.05-0.15 wt% and zirconium oxide 0.02
~0.1wt% or vanadium oxide 0.02~0.1w
A method for producing an oxide magnetic material, which comprises sintering an oxide containing t% and then cooling it to an oxygen concentration P% that satisfies the following formula. -6800/T+b l <log P< -4300
/T+b dashi stock, ■; humidity temperature ℃), P; oxygen concentration (
%), b+, t+z: Constants set to match the oxygen concentration during sintering. 3 Iron oxide 50-56 mol%, manganese oxide 21-38
mol%, basic composition consisting of 6 to 25 mol% zinc oxide,
Calcium oxide 0.01-0.1 wt%, cobalt oxide 0.05-0.15 wt% and zirconium oxide 0.02
~0.1wt% or vanadium oxide 0.02~0.1w
A method for producing an oxide magnetic material, characterized in that after sintering an oxide containing t%, the oxide is cooled to an oxygen concentration P% that satisfies the following formula, and further subjected to hot isostatic pressing. -6800/ T+b I < log P < -4
300/'r1b Soup stock, T; Temperature (℃), P;
Oxygen concentration (%), b, , b, ; Constant set to match the oxygen concentration during sintering.