JPH03278407A - Composite magnetic material - Google Patents

Abstract

PURPOSE:To heighten electric resistance by covering a grain surface of a magnetic material with an extremely thin dielectric or an insulating material. CONSTITUTION:A first material 1 of a magnetic metal such as iron, nickel and an alloy containing at least one kind of these and a second material 2 different from the first material 1 either in the number, the kind or the valency number of its constituent elements or constituent ions or in the crystal constitution are mixed to be heated generally at not less than 300 deg.C and impressed with high pressure not less than 100kg/cm<2> for being molded to high density so as to be in a state where the grains of the first material 1 are encircled by the continuation of the material 2. In the case the material 2 is dielectric or insulating, high saturation magnetic flux density is attained due to an overwhelmingly high rate of the material 1 and the dielectric or insulating material 2 encircules the material 1 so that electric resistance is high and eddy current loss is little in a high frequency region.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to magnetic materials used in magnetic heads and the like, and particularly to composite magnetic materials.

BACKGROUND ART Magnetic metals have traditionally been used as magnetic materials for electronic parts and devices when high magnetic flux density is required. However, when used in a high frequency region, magnetic metals have low electrical resistance and therefore have a large eddy current loss. Problem to be Solved by the Invention Even if a composite magnetic material is used, which has a high electrical resistance by combining it with an insulating material 102 made of an insulating material, magnetic metals have a low electrical resistance. Current loss increases. Therefore, it has the feature of high saturation magnetic flux density, and although it is difficult to use in the high frequency range, ferrite, which is an oxide magnetic material, has an electrical resistance of more than 101 times that of magnetic metal materials, and has a low eddy current loss in the high frequency range. Force forks are far superior to magnetic metals in terms of reduction.The saturation magnetic flux density is approximately 1/2 or less than that of magnetic metals, so they cannot be used in electronic components and equipment that require high saturation magnetic flux density. Another problem was that conventional composite magnetic materials of magnetic metal and insulating material were simply a composite of the two.
Characteristics of Composite Magnetic Materials (Note: This is simply a composite of the characteristics of each component material on average.) In other words, as shown in Figure 9, the component ratio of the insulator 102 is increased to obtain high electrical resistance. In addition, in conventional composite magnetic materials, the high magnetic flux density of the magnetic particles 101 is weakened by the insulating material. The insulator 102 has a structure in which the magnetic particles 101 are divided into discontinuities.The magnetic flux passing through the inside of the composite is blocked by the non-magnetic insulator 102, and the magnetic permeability of the composite is also reduced. The present invention has been made to address such conventional problems, and it is an object of the present invention to provide a composite magnetic material with high saturation magnetic flux density, high electric resistance, and high magnetic permeability. Means for Solving the Problems The present invention provides a first substance in the form of particles, and a first substance in which the first substance differs in at least one of the number, kind, valence, or crystal structure of constituent elements or constituent ions. A microparticle-sized composite composed of at least two types of substances other than the first substance, the first substance being a magnetic material, and the thickness of the substance other than the first substance being equal to the thickness of the particles of the first substance. The conventional problems have been solved by using a composite magnetic material that is smaller than the diameter, forms a continuous phase separate from the first substance, and has a porosity of 5% or less. Then, by almost covering the particle surface of the first substance made of a magnetic material with an extremely thin dielectric or insulating material, the electrical resistance of the high-density sintered body is increased and the thickness of the dielectric or insulating layer is reduced. Although it is possible to achieve high magnetic properties by using conventional composite magnetic materials, it is possible to achieve high magnetic properties by simply using conventional composite magnetic materials. In contrast, the composite magnetic material of the present invention provides a novel magnetic material that exhibits the properties of its constituent elements at the same time.

Furthermore, since the composite magnetic material has a porosity of 5% or less, the magnetic properties and mechanical properties of the composite magnetic material of the present invention are improved.

Embodiment FIG. 1 shows an enlarged view of the cross-sectional concept and essential parts of the composite magnetic material of the present invention. The first substance l contains a particulate magnetic material.
The substance 1 is surrounded by another phase and forms a continuous phase.
It is composed of a substance 2 other than the substance .

By adopting the configuration as shown in FIG. 1, the composite magnetic material 1 of the present invention exhibits unique magnetic properties.

For example, if the substance 2 other than the first substance contains a dielectric or insulating material, the composite magnetic material itself has a high electrical resistance l - the thickness of the continuous phase formed by the substance 2 other than the first substance is the first If it is thinner than the particle size of substance 1, then the composite magnetic material is
Magnetic properties comparable to those obtained with [materials] can be obtained. Or the first
When the substance 2 other than the substance 2 contains a soft magnetic material (as shown in FIG. Examples of materials include magnetic metals such as iron, nickel, and cobalt, and alloys containing at least one of these metals. Examples of the above alloys include Fe-AL, Fe-3L, re-Ni, and Fe.
-Al-3L Mo-Ni-Fe, Fe-8i-
Al-Ni, 5i-Al-Fe-Co, etc. may be mentioned, but also substances other than the first substance of the present invention. which are different substances,
Specifically, the materials provided include E Ale's,
5iOa, metal oxidation method AIN such as MgO, CaO, etc.
Metal nitrides such as BN or metal oxynitrides Mη-
Examples include ferrite compounds such as Zn-ferrite and Ni-Zn-ferrite. That is, for example, when the substance 2 other than the first substance is an oxide of the constituent elements of the first substance 1, the substance 2 other than the first substance is the first substance 1, the number of constituent elements, the valence, and the number of constituent elements. It can be said that at least four of the crystal structures are different.

The composite magnetic material of the present invention can be roughly divided into two steps: a mixing step in which the first substance and a substance other than the first substance are mixed together, and a molding step in which this mixture is formed into a predetermined shape.

A mixing step (i.e., bringing the first substance into contact with an active gas, causing the active gas to react with the surface substance of the first substance,
As a result, a method of forming a layer of a material other than the first material, a method of using a material other than the first material as a vapor deposition source or a target (a method of performing vapor deposition or sputtering on the first material, a method of forming a layer of a material other than the first material, 1 and a substance other than the first substance using a stirring and dispersing means such as a ball mill or a vibration mill. Depending on the method, the continuous phase formed by a substance other than the first substance and the size of the first substance may vary depending on the type of composite magnetic material or the applied device. When applied to a magnetic head that requires the most stringent characteristics, the size of the first dirt is as follows.First, the grain size of the first substance (the size of the magnetic domain determined by the other material) is as follows. A range of 0.1 to 100 is preferable.
If the thickness of the continuous phase is less than 5 nm, the insulating or dielectric properties will generally be insufficient, and the electrical resistance of the composite magnetic material will be low. Magnetic properties in high frequency range are poor due to eddy current loss. If the thickness exceeds 50 mm, the distance between magnetic metal particles separated by the non-magnetic continuous phase becomes too large, and the magnetic permeability as a composite magnetic material tends to decrease. Therefore, when using a composite magnetic material as a magnetic head, it is preferable to use a mixture of the first substance and a substance other than the first substance because it can obtain high-performance magnetic properties even in a high frequency range. A composite magnetic material is obtained by molding to a high density.

This molding process generally involves applying high pressure and heating at high temperatures to form the parts, thereby achieving high density molding.

Normal heating temperature is 300℃ or higher, and pressurization is 100kg.
/cm2 or more, a composite magnetic material with a porosity of 5% or less can be obtained by molding under high temperature and high pressure.

When the porosity exceeds 5%, some of the pores inside the composite magnetic material are connected to the outside (referred to as open pores), and since the open pores communicate with the outside world, corrosion etc. occur and the composite magnetic material deteriorates. This leads to disadvantages such as a decrease in magnetic properties or workability, and insufficient mechanical strength. If the porosity is 5% or less (that is, the pores are shut off from the outside world and are called closed pores), these drawbacks can be overcome. Even more preferably, the porosity is 3% or less; for example, when the composite magnetic material of the present invention is applied to a magnetic head, the porosity is 0.
It is about 5%, most preferably about 0.1%, which can be achieved according to the present invention.

In this forming process, since the first material is compressed under high pressure, if the amount of plastic deformation between the first material and the material other than the first material is different, the material other than the first material will generally break and the first materials will be directly bonded to each other. It may be molded. This phenomenon tends to occur when a substance other than the first substance covers the first substance and forms a thin layer (for example, if the substance other than the first substance is dielectric or insulating). When the first substances are connected to each other continuously, the electrical resistance of the composite magnetic material decreases, and in extreme cases, it becomes no different from that of conventional metal magnetic materials4.For this reason, during the forming process. The part other than the first substance is torn and the first substance
The molding process may be performed while repairing the part where the substance appears with a substance other than the first substance or a similar substance. When a reaction product is formed between a substance and an active gas (such as a repair method by performing a molding process in an active gas atmosphere, or a method in which a substance exhibiting superplasticity such as apatite is mixed in advance) I do.

Note that the active gas includes oxygen gas, nitrogen gas, etc., and the partial pressures of these gases are appropriately selected.

One embodiment of the composite magnetic material produced in this way (as shown in FIG. 1, particles of a magnetic first substance 1 are surrounded by a continuous phase of a substance 2 other than the first substance). Tona 4 In a composite magnetic material with such a configuration, especially when the substance 2 other than the first substance is a dielectric or insulating substance (Table 1), the proportion of the first substance 1 in the magnetic metal material is overwhelmingly The first material 1 is surrounded by a dielectric or insulating material 2 other than the first material.
The electrical resistance of the composite magnetic material is high and the eddy current loss is small even in the high frequency range (for example, 2 MHz or higher), and the thickness of the substance 2 other than the first substance is the same as that of the first substance 1. It has the characteristics of low porosity, low area ratio of the triangular points 3 where three or more of the first substances 1 gather to the entire complex, and high magnetic permeability.

In addition to these magnetic characteristics, mechanical properties such as L strength and workability are also much better than conventional ones.

Further, an example of another embodiment of the composite magnetic material of the present invention is shown in FIG.

The first substance 11 has a flat shape, and this first substance 1
A substance 12 other than the first substance forms a continuous phase around the substance 1 .

Such a form of composite magnetic material! This can be achieved by applying pressure from one direction or applying forces of different magnitudes from multiple directions during the molding process. Also, from the beginning, the first substance 11
Of course, it may have a flat shape.

By using the first substance 11 having this flat shape, the area ratio of the triangular points 13 is generally lower than that of the triangular points 3 in FIG. The flat shape referred to in the present invention, which is preferable because of improved properties, may be any shape such as a disk shape, an oval shape, a spheroid shape, a plate shape, or a needle shape.In short, the first substance 11 has a clear long axis. As long as it has a shape (- In addition, the first substance 21 is flat so that the flat planes are aligned as shown in FIG. 3, and the axis of easy magnetization 4 is in the long axis direction.
When arranged, the magnetic anisotropy increases and can be applied to, for example, a high-output magnetic head.It is preferable that the magnetic permeability C'!
, a high value exceeding the so-called limit of Snooks.

The ratio of the short axis to the long axis of such first substance 11 or 21 is preferably about 173 to 1/10, and the length of the short axis is preferably 3 to 5 μm. If the ratio to the long axis is greater than 1/3, it is difficult to obtain magnetic anisotropy, and therefore it is difficult to obtain very high magnetic permeability. Also l
If it exceeds /10, the flat particles tend to break during molding, and careful molding becomes necessary.

Note that as a method of introducing magnetic anisotropy into magnetic metals,
In addition, for example, magnetic metals such as Fe-3i-A1 alloy have C
Methods of adding carbon dioxide, etc. Methods of forming CO ferrite on the surface of metal magnetic powder Methods of changing the composition of metal components in the flat powder by giving a gradient in the longitudinal direction. In addition, Fe-3i-Al-Ni is particularly preferred as a magnetic metal that can easily plastically deform granular particles to form flat grains.

Another embodiment of the present invention is as shown in FIGS. 4 and 5. That is, the composite magnetic material shown in FIGS. 4 and 5 includes a plurality of layers 301 and 401 of a first material each composed of a first material 31, 41, and a material 3 other than the first material.
It has a structure separated by 2.42. Moreover, even if the first materials 31 or 41 existing in the same layer are in contact with each other, extremely large anisotropy appears in the electrical resistance in such a structure. Therefore, if the direction in which the first materials 31 or 41, which have very low electrical resistance, are in direct contact with each other matches the direction of the magnetic flux, the magnetic flux will not be affected by the dielectric or insulating coating, and the magnetic permeability will be Go up. In particular, when the longitudinal direction of the first material 41 and the direction of the magnetic flux are made to match as shown in FIG. 5, the magnetic permeability is further increased.

The composite magnetic material of the present invention can be used as a hard magnetic material or a soft magnetic material in various fields of application.

For example, magnetic particles containing at least one of iron or cobalt and having a single domain structure are used, and a magnetic material whose axis of easy magnetization is aligned in one direction is used as a permanent magnet, and the maximum energy product (Bl()) is used as a permanent magnet. It has a large .

Furthermore, the composite magnetic material of the present invention is suitably used as a magnetic core material for transformers and magnetic heads. Since both have the above-mentioned configuration, there are few defects caused by eddy currents, and they can be used effectively in a high frequency region. When used as a magnetic core of a magnetic head, a composite magnetic material containing a first substance having a flat shape, whose porosity is preferably 0.5% or less, preferably 0.1% or less, is used as a magnetic core of a magnetic head. For example, a magnetic head 6 as shown in FIG. 6(a) is preferable because a high output can be obtained by using the magnetic head as a magnetic core. As shown in FIG. 6(b), the flat surface of the flat powder 14 is perpendicular to the running direction 7 of the magnetic recording medium. If there is, high output characteristics can be obtained in a wide high frequency range of, for example, 40 to 100 MHz.

Furthermore, when the composite magnetic material of the present invention is used in a magnetic head, etc., it has a low porosity and therefore has excellent wear resistance, and will be described below with reference to non-limiting examples.

Example 1 The average grain size of Fe-2%Si magnetic alloy as the first material was 2.
By heating and oxidizing the 5 μm powder in air at 850°C for 3 hours, a thin layer of a substance other than the first substance is evenly formed around the periphery.9 The substance other than the first substance is almost silicon oxide. This composite was mixed with 0.05% low-temperature wax and molded, and after removing the binder, it was packed into a heat-resistant container L750
After hot pressing at 250 atm for 1 hour, the first
As shown in the figure, a high-density composite sintered body with a porosity of 5% or less was obtained, which was almost uniformly covered with a material 2 other than the first material 1 and the polished surface. After detailed evaluation, the area of triangular point 3 where three or more particles meet was less than 2.5%, but the resistance of this cross section was more than 20MΩ and could not be measured with a tester.Also, the hardness was about 125% of the raw material. In the cutting process using a diamond blade, the conventional material required frequent dressing, whereas the material of the present invention reduced the dressing to about 172, which resulted in a significant improvement in machinability. 9 Example 2 By making the hot press in Example 1 uniaxial, the shape force (second
As shown in the figure, the first substance 11 is transformed into flat particles with a ratio of 2:1 or more, and is covered with a substance 12 other than the first substance.

By adjusting the pressure and uniaxiality, it is possible to further change the flatness, and it is possible to achieve a level of 1 degree per discharge.By flattening the first material 11 in this way, higher density can be achieved. The porosity of Example 1 was improved from 5% to 3%. Such materials 41 Different methods of hardness Different methods of abrasion resistance
It has magnetic anisotropy, and the porosity is improved by 20 to 50% on the plane perpendicular to the flat plane. The volume is reduced by the improvement in , and the loss is reduced accordingly.

Effects such as those described above cyo The same effect is obtained not only when the first substance 11 is a single substance, but also when it is a composite fine particle.
It goes without saying that an excellent transformer can be realized not only with the alloy material used in the explanation but also with many other metal materials.Example 3 As the first substance, Fe with an average grain size of 0.2 μm -C.

Alloy spherical powder (powder A) with a long axis of 0.1 μm and a short axis of 0
, 05μm acicular powder (powder B) were sputtered to form a 5if2 film on the powder surface for 5mm-20m.
These two types of powder covered with a thickness of m were stirred during glycerin welding.
The slurry containing the flat powder 11 formed by molding using the wet magnetic field press shown in FIG. The wet molding method is equipped with a magnet 10 that can apply a magnetic field (magnetic field strength 10,000 G) in a direction perpendicular to the pressing direction (pressure 1000 Kg/cm') at the same time. A molded body was produced by magnetic field pressing, and the strength of the molded body A using powder A was ζ. Above: Molded bodies A and B, which were oriented molded bodies in which the long axes of the powder were aligned in a certain direction, were heated in an N2 atmosphere at 600 to 800 °C.
Hot press (500 kg/cm") in the same direction as the pressure molding direction at 0°C. When the magnetic properties of the two types of permanent magnets obtained were measured, it was found that the sintered body In A, (BH) was 6.5 MGOe, while in sintered body B, (BH) was 50 to 60 MGO.
e, which is higher than the conventionally reported (B) (
BH) , , , was large compared to the FeCo system where the size of the needle-like powder was 1 to 3 μm. When acicular powder of 1 μm or more is used, the (BH) of the sintered body -
-xIt 6~7 The permanent magnet of this example obtained almost the same value as when using MGOe and spherical powder.
Not only is , , large, but its electrical resistance is also 10@
It showed a high resistance of ~109Ωff1fi+, which is comparable to that of an insulator.Also, the first material used in this example is Fe-Co based.The Fe-Co based alloy has the highest saturation magnetic flux density. This is because a material with a large (BH) is produced.Example 4 Fe-Al (AI content 5%) alloy powder with an average particle size of 30 μm was heated at 800°C for 3 hours as the first substance. By heating and oxidizing in air, a thin layer of a substance other than the first substance is evenly formed around the first substance. A plate made by mixing 0.05% of low-temperature volatile wax with this composite and removing the binder was filled in a heat-resistant container and hot-pressed at 700°C for 1 hour at 1000 atm, with a porosity of 0.5. After obtaining a sintered body with a high density of 50%, we investigated the microstructure in more detail.
．． It was found that it was very small, less than 3%.9 This suggests that this is one of the reasons for the high properties described below.

The resistance of this cross section was more than 20MΩ, which could not be measured with a tester, and the hardness was improved to about 125% of the raw material.When hot pressing was further carried out at 800℃, a porosity of 0.1% was obtained. 9. The magnetic flux density of the obtained material was observed to be over 15,000C.The oxide film thickness at this time was approximately 0. 2 μm, which is within the range that can be used for audio magnetic heads.Example 5 By making the hot press of Example 4 uniaxial, the shape of the first material, which is nearly spherical, can be flattened by a ratio of 2:1 or more. By adjusting the pressure and uniaxiality, the flatness can be further changed to about 10:1, and such materials have different hardness, different wear resistance, and magnetic properties. It has anisotropy, and these characteristic values are improved by 20 to 50% on the plane perpendicular to the flat plane.Magnetic heads using such a plane also have improved magnetic properties (magnetic permeability). Coercive force (coercive force reduced by about 20%) has been improved, and abrasion resistance has also been improved by about 15%.By aligning the particularly flat surface with the direction in which the tape runs, the magnetic head can operate at 10 to 30 MHz. The output is 1~1. The magnetic head output was further improved by 5 dB, and demagnetization was also reduced.Conversely, by making the flat surface perpendicular to the tape running direction, a significant improvement in the magnetic head output in the range of 40 to 100 MHz was observed.9The coercive force in this direction was It is presumed that the high magnetic absorption anisotropy is useful for improving the head output.

It goes without saying that the above effects are not limited to the alloy materials used in the explanation, but apply to many other metal materials.
% As described above, the magnetic head 1 using the composite magnetic material of the present invention can be said to be ideal not only for magnetic heads for audio but also for future high-definition VTRs and computers.Example 6 Compositional force expressed in weight ratio<, Si:A1:Fe=1
5i-Al-Fe alloy powder of 0:6:84 and compositional strength expressed in weight ratio (Si:Al:Ni:Fe=6:4:
3+87 5i-Al-Ni-Fe alloy powder of each composition is melted by high-frequency induction heating (melting is used exclusively in the metal industry), and the ingot is crushed with a hammer mill. These powders were prepared by classifying them to an average particle size of approximately 20 μm using a #250 mesh sieve or less, and were heated at 1200°C to 13°C in an inert gas atmosphere.
By heating the powder at 00°C and colliding it with a cooling plate at high speed, the powder was flattened.
The aspect ratio m (m
= 1/l, 1:length:thickness) was measured, and the result was 9.5i-Al-Fe alloy powder.
A flat powder with a diameter of 40 μm and a thickness of 3 to 4 μm was obtained using the Ni-Fe alloy powder, and the specific surface area S was 0.04 to 0.05 m2/g using the starting material powder. S of the 5i-Al-Fe alloy in which flattening was attempted was approximately 0.2 m''/g, and the flat 5i-Al-Ni-Fe alloy
The S of the alloy is approximately 0.1 m''/g, and the aspect ratio m is approximately 1 for the 5i-Al-Fe system, whereas the 5i-A
In the l-Ni-Fe system, a value of about 10-15 can be obtained, and the value of the specific surface area S after 9 flattening forces ζ & 5i-AI-
0 for Fe alloy, '1. The strength of the 5i-Al-Ni-Fe alloy is approximately the same order as 0.1. Observation using a scanning electron microscope shows that the former has more fine powder than the 5i-Al-Ni-Fe alloy.
2. It is also possible that the specific surface area S was close to that of the 5i-AI-Fe due to the shape (not very flat, L) and many unevennesses on the powder surface.
The alloy is harder and more susceptible to brittle fracture, indicating that the powder is destroyed without flattening.

Regarding flattening other than collision plate method L stamp mill,
The force (
Similar to the collision plate method, the 5i-Al-Fe alloy (5i-Al-Fe alloy) is difficult to form into a thin plate, deforms from a spherical shape to a rectangular shape, or partially breaks, making it impossible to obtain a flat powder. 5i-Al-Ni-Fe alloy powder (also flattened with a stamp mill and a ball mill with an aspect ratio m of 10)
~20 flattened powders were obtained, resulting in a total of 9 comparisons.
For example, the saturation magnetic flux density is about 8,000 G, which is insufficient for application to magnetic heads due to magnetic properties, and it also has poor abrasion resistance against sliding friction with magnetic tape. Due to its low density, it cannot be used as a starting flat material for high-frequency magnetic heads.The saturation magnetic flux density of 5i-Al-Fe alloy is about 10,000G, Approximately 1
5000G, and the wear resistance (respectively) is good, about 2 to 10 times that of permalloy alloy, and is better than fi 5i-Al-Fe alloy.
Did you know that i-AINi-Fe alloy is easier to obtain flat powder, has excellent magnetic properties, and has good wear resistance? =
The surface GQ of this 5i-Al-Ni-Fe alloy flat powder and the flattened 5i-Al-Fe alloy powder are
An insulating layer of ~3 nm is formed, and the main component of the oxide layer is A12ea. Auger electron spectroscopy (AE)
S) Place these coated flat powders removed from analysis in ethylene glycol. About 15 g of ethylene glycol per 25 g of powder.
After stirring and mixing at a ratio of m1, put the slurry into a mold.
Pressure is applied from above and below (pressure: 300Kg/cm"). This mold has pores on the top and bottom that allow only the dispersion medium to be discharged out of the mold. A comparison experiment in which a powder-oriented molded body was obtained in which the plate surfaces of the flat powder were aligned parallel to each other in the vertical direction.A powder-oriented molded body was also produced using flat powder without an insulating coating layer. Three types of molded bodies were heated to 1200 to 130 in an inert atmosphere.
The sintered body C was hot-pressed at a temperature of 0°C under a pressure of 30 MPa for 3 hours, and the pressing direction was made to match the pressing direction during molding. When the cross section of the material was observed under a scanning electron microscope, it was found that when using a raw material with an oxide insulating layer formed on the surface of the flat powder of 5i-AI-Ni-Fe alloy, the metal magnetic powder had a high density. A magnetic layer with a thickness of 3 to 5 μm sintered to
It is a composite magnetic material made of alternating brick-like insulating layers of A1203 with a thickness of 10 to 30 ηm.The starting material is a 5i-AI-Fe alloy powder that has been flattened and oxidized. The oxide insulating layer is cut here and there by metal particles, and the metal particles and the insulating layer have a fine structure in which they intertwine, and 5i-Al-
A sintered body made from Ni-Fe alloy flat powder without an oxide insulating layer as a starting material had a fine structure in which only plate-shaped metal particles were oriented. Figure 3 shows the flat particles of this example. A schematic diagram of a composite magnetic material using .

21 is a first material and is surrounded by an insulating layer.

When we measured the electrical resistance of a composite magnetic material (approximately 5 mm thick and approximately 30+ nm long) made using a raw material with an oxide insulating layer formed on the surface of flat powder of 5i-Al-Ni-Fe alloy, we found that the flat powder plate In the direction perpendicular to the surface, it showed a high resistance of IMΩ, comparable to that of an insulator, and when the electrical resistance was measured in the direction parallel to the plate surface of the flat powder, it showed a resistance of about IMΩ. A sintered body using a raw material with an oxidized insulating layer formed on the surface of 5i-Al-Fe alloy flat powder and Si, which exhibited a resistance value of several tens of MΩ.
-A1-When measuring the electrical resistance of a sintered body made of Ni-Fe alloy flat powder without forming an oxide insulating layer, the electrical resistance was only about several 100 μΩ, which is about the same as that of a magnetic metal material. The magnetic properties of a magnetic core made from a 5i-Al-Ni-Fe alloy flat powder with an oxide insulating layer formed as a starting material were measured in the direction perpendicular to the plate surface of the flat powder and in the direction parallel to the plate surface. Magnetic permeability was measured in two directions'), 10KHz ~ 5
At a frequency of MHz, the frequency of the flat powder is 50. The saturation magnetic flux density of this composite magnetic material is 1,000 to 1,500 in the direction parallel to the plate surface. , 15000G, which was almost the same as the saturation magnetic flux density value of the metal magnetic material of the starting raw material powder. -A1
- When measuring the magnetic permeability of a sintered body made of flat Ni-Fe alloy powder without an oxide insulating layer, it is found that the permeability is 100 to 10 in the low frequency range of 10 to I KHz.
If the force exceeds IKHz, a low magnetic permeability value of several 10 or less can be obtained. Example 7 Two types of 5i-Al-Ni-Fe alloy powders similar to those in Example 6 were prepared. Among them, the composition of various metal raw materials was in wt% ratio. And Si:A
1:Ni:Fe = 6:4:3:87. This was mixed in an inert atmosphere. High-frequency induction heating was used to melt the mold. After cutting the melted ingot into blocks of appropriate size, this was further heated. The molten metal is melted by high-frequency induction heating and blown into N2 gas using high-pressure Ar gas to produce so-called N2 atomized spherical powder.This N2 atomized spherical powder is classified to collect fine powder of #250 mesh or less. Another powder, called starting material A, has the same composition as starting material A. A block prepared by melting is coarsely pulverized in a hammer mill, and then finely pulverized in a jet mill using N2 gas as a carrier gas. The specific surface area S of starting material A and starting material B was measured.The specific surface area S of starting material A and starting material B was measured. However, in scanning electron microscopy observation, starting material A L average particle diameter of approximately 15-16 μm
The starting material B was a spherical powder with a well-uniformed particle size, and the starting material B was a lumpy powder with an irregular shape. Proceed as in Example 2 Flattening using a ball mill for 50 hours The obtained flattened powder was measured using a scanning electron microscope to evaluate its shape, aspect ratio m, etc. The results were as follows: Flattening using starting material A The powder (flat powder A) has an oval shape, the diameter of the plate is approximately 30μ, and the thickness is approximately 3~5μ.
The distribution of the plate diameter was also narrow, 20 to 40 μm.
The value of the aspect ratio m of approximately 10 was obtained, and the value of the aspect ratio m was approximately 10.
The circumference of the plate is uneven, and the diameter of the plate is 3.
The thickness ranges from ~60μm, and the plate thickness is 0.5μm.
5 to 20μ peaks and irregularly flat powder A and flat powder B
Each was oxidized in air at 400℃ for 10 minutes.
An insulating film with a thickness of 20 to 50 nm was formed. These film-forming treated powders were wet-formed in the same manner as in Example 3 to orient the flat powder, and the molded body was placed in a hot press mold.
The sintered body obtained by hot pressing at 1200 to 1300°C and a pressure of 300 kg/cm2 for 3 hours is a high-density sintered body with a porosity of 1% or less. (Approximately 5 mm tail 30 m
m diameter) (y) High electrical resistance, strength with a resistance of 20 MΩ or more Sintered body made from flat powder B as a starting material (same shape,
If the diameter is approximately 5 mm and the diameter is 30 mm, its electrical resistance is 1.
It is ~2MΩ.9 This is because there are many irregularities around the edges of the flat powder.It is thought that this is because the thin insulation coating becomes easy to tear during the process of forming a high-density sintered body.When used in a high frequency region, Since eddy current loss must be reduced, high electrical resistance is preferable, and it is clear that spherical powder is preferable as a starting material for making flat powder. Of course, flat powder B can also be used in fields where it is not required.4 Example 8 A composite magnetic material made from flat powder A produced in Example 7 as a starting material is used as a magnetic core, and the running direction of the magnetic tape is set to the longitudinal direction of the flat powder. A video magnetic head (magnetic head A) with a track width of 30 μrn and a magnetic gap of 0.3 μm
) A magnetic head with the same shape as described above (magnetic head B) was manufactured using a conventional material obtained by hot press sintering the starting material B described in Example 7 without oxidation treatment. Magnetic tape (Hc approx. 50
00e) was used to evaluate the aforementioned magnetic head A and magnetic head B. At a frequency of 5 MHz, magnetic head A had a higher force of 5 to 10 clB than magnetic head B. Furthermore, the strength of comparison was the same. Using metallic magnetic spherical powder with a diameter of approximately 20 μm, the surface was oxidized to create an insulating film, and this was sintered to create a composite magnetic material. A magnetic head with the same shape was created using this as a magnetic core. The results of the evaluation were as follows: Magnetic head A had a 3 to 5 dB higher output at the same frequency than magnetic head B.
Example 9 with lower output not obtained Si 9. 5wt tail Al is 6wt%, Fe is 84wt
%Co is 0. 5i-Al-Fe-C with a composition of 5 wt%
o Alloy flat powder (thickness/longitudinal ratio is 1/3 to 1/
10, 3 μm thick) was heat treated at 800℃ for 1 hour in Ar containing 0.05% 02 gas.The surface of the powder was oxidized very thinly.The thickness of the oxide film was determined by the increase in weight of the powder and the specific surface area. Calculated results and Auger analysis of the powder surface yield approximately 10-20 nm
Mix these flat powders into a slurry using a glycerin solution as a solvent, and put this slurry into the wet magnetic field press apparatus outlined in Figure 7 in the same way as in Example 3, and set the direction in which the magnetic field is applied. A molded body was created by vertical pressure pressing. This molded body was wet-axially (unidirectionally) pressed so that the flat surface of the first material 21 had a flat shape as shown in FIG. They are arranged perpendicular to the pressing direction and are aligned in the magnetic field direction 5 in the direction of the easy magnetization axis 4 by the applied magnetic field. This molded body is 1
Hot press (500 kg/cm) in the same direction as the pressure molding direction for 4 hours at 850 ° C.
'') A composite magnetic material was prepared as an l-magnetic core, the surface of the obtained magnetic core material was polished, and its sintered density and porosity were measured.As a result, the relative density of the sintered body was 99.
5% or more, the porosity is 0.5%, the electrical resistance of this magnetic core material is 20MΩ or more, and the saturation magnetic flux density is 100OOG or more. = The magnetic permeability of this magnetic core material is measured in two directions, one parallel to the longitudinal direction of the first substance 21 and the other perpendicular to the plate surface of the first substance 21. The magnetic permeability in the direction is about 500 when the measurement frequency is 10MHz, and 200 when the measurement frequency is 20MHz.
Force length was about ~300 Magnetic permeability L in the direction perpendicular to the plate surface of the first material 21 1300S20M at 10MHz
Example 10 Using the magnetic core material prepared in Example 9, a VTR magnetic head with a magnetic track width of 15 μm and a magnetic gap length of 0.2 μm was manufactured. Three types of magnetic heads were fabricated. One is one in which the longitudinal force of the flat first material of the composite magnetic material of the present invention is parallel to the sliding direction of the magnetic tape (magnetic head a), and the other is one in which the longitudinal force is parallel to the sliding direction of the magnetic tape. The flat plate surface of the first substance of the composite magnetic material of the invention is perpendicular to the sliding direction of the magnetic tape (magnetic head b), and the last one is the one in which the flat plate surface of the first substance of the composite magnetic material of the invention is perpendicular to the longitudinal direction force of the first substance of the composite magnetic material of the invention. A magnetic tape coated with 47-Fe2r (with a holding force of HCl00
The results of investigating the recording and reproducing characteristics of three types of magnetic heads in the frequency range of 0 to 15000e) and 5 to IOM) Tz.
Compared to Comparative Example 1, the S/N ratio was about 3 to 5 dB higher. When the recording and reproducing characteristics of a magnetic tape similar to that of Example 10 were evaluated on a VHS type VTR magnetic head made of conventional Mn-Zn ferrite single crystal. , compared to the magnetic head b of Example 10, the S/N ratio was about 5 to 7 dB lower. Effects of the Invention The composite magnetic material of the present invention includes a particulate first substance, and the first substance is a constituent element. or a microparticle-sized composite composed of at least two substances other than the first substance in which at least one of the number, type, valence, or crystal structure of constituent ions differs; the substance is a magnetic material, the thickness of the substance other than the first substance is thinner than the particle size of the first substance, and forms a continuous phase that is separate from the first substance, and the porosity is By providing a composite magnetic material with a magnetic flux density of 5% or less, it is possible to achieve a magnetic material with high saturation magnetic flux density, high electrical resistance, and high magnetic permeability.

[Brief explanation of drawings]

FIGS. 1 to 5 are conceptual cross-sectional views of main parts showing the structure of the composite magnetic material of the present invention. FIG. 6(a) is the positional relationship between a magnetic head and a magnetic recording medium in an application example of the composite magnetic material of the present invention. Fig. 6(b) is a conceptual main part perspective view showing the relationship between the flat first substance and the running direction of the magnetic recording medium.
Figure 7 is a schematic diagram showing a wet press apparatus for producing an embodiment of the composite magnetic material of the present invention Figure 8 is the magnetic properties of the composite magnetic material of the present invention @ Figure 9 is an overview of the concept of the conventional composite magnetic material FIG. 1, 11. 21. 31. 41...first substance, 2゜12, 32. 42... Substance other than the first substance, 3゜13... Triangular laziness 4... Easy magnetization a 7
... Running direction 14 ... Flat powder 4 & 101 ...
Magnetic particles, 102...insulation

Claims (5)

[Claims] (1) A particulate first substance and the first substance are substances other than the first substance that differ in at least one of the number, type, or valence of constituent elements or constituent ions, or crystal structure. A fine particle size composite composed of at least two types of substances, wherein the first substance is a magnetic material, and the thickness of the substance other than the first substance is smaller than the particle size of the first substance. A composite magnetic material that is thin, forms a continuous phase separate from the first substance, and has a porosity of 5% or less. (2) characterized in that the substance other than the first substance contains either a dielectric material or an insulating material;
The composite magnetic material according to claim 1. (3) The composite magnetic material according to claim 1, wherein the continuous phase has a thickness of 5 to 50 nm. (4) The composite magnetic material according to claim 1, wherein the first substance has a flat shape. (5) The composite magnetic material according to claim 1 or 4, having a fine structure in which the axis of easy magnetization of the first substance is aligned in a certain direction.