JPH03294403A - Shape anisotropic soft magnetic alloy powder - Google Patents

Abstract

PURPOSE:To extremely easily manufacture shape anisotropic soft magnetic alloy powder without lower soft magnetic characteristic by pulverizing an ingot of Fe series alloy incorporating the specific contents of Si and Co. CONSTITUTION:Fe-Si-Co series alloy of composition of high purity Fe and Si, Co composed of X% (4 - 27%) Si, Y% (1 - 30%) Co and (7X - Y)/10<=16 and the balance of Fe, is melted with a high frequency electric furnace in inert gaseous atmosphere of Ar, etc., and this ingot is pulverized with a jaw crusher. The planar shape anisotropic particles having 30 - 50mum average diameter, 3 - 5mum average thickness and about 7 - 13 average ratio of diameter/thickness, is obtd. and the soft magnetic alloy powder having easily magnetized axis to unidirection in parallel to the plate surface can be stably manufactured.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention grinds a highly magnetized metal powder mainly composed of Fe using a conventional mechanical grinding method, and also imparts shape anisotropy to the powder. As a result, the soft magnetic properties were improved in a specific direction. This invention relates to shape-anisotropic soft magnetic alloy powder.

[Prior Art] Conventionally, iron (Fe), which is inexpensive and has high magnetization, has been the most important substance in magnetic materials. in general,
Metals containing a large amount of Fe exhibit soft magnetism that can be easily magnetized. These soft magnetic alloys whose main component is iron were usually used in the form of blocks or plates.

However, in recent years, methods such as molding and coating using powder whose shape can be easily selected have been utilized. Generally, since the proportion of metal in powder decreases, the amount of magnetization per unit volume tends to decrease. In addition, as the grain size increases, the influence of the demagnetizing field increases, and the magnetization characteristics tend to deteriorate.

In order to alleviate these negative decreases, it is useful to impart shape anisotropy to the powder and facilitate magnetization only in a specific direction.

In general, it has been believed that soft magnetic alloys containing Fe as a main component are sticky and cannot be pulverized by normal mechanical pulverization methods.

Therefore, there are methods to obtain alloy particles by molten metal spraying, methods to produce thin strips by liquid quenching method and then crush them to obtain alloy powder, and methods to obtain alloy particles by adding metalloid elements other than Fe.
A method of improving the crushability of an alloy is considered to be a general method for producing metal powder containing a large amount of Fe.

[Problems to be solved by the invention] However, in the above-mentioned molten metal spraying method and liquid quenching method,
It is necessary to introduce expensive equipment, the amount of processing is small, and the stable manufacturing conditions are narrow.

In addition, in the method of adding a metalloid element to an alloy, an increase in the amount added generally leads to a decrease in 4πIs and an increase in 'IHC, and it often becomes impossible to obtain sufficient properties as a soft magnetic material.

Therefore, the technical problem of the present invention is to eliminate these production drawbacks and produce alloys containing Fe as the main component by manufacturing ingots and mechanical crushing, which has been practiced for a long time and is said to be technically almost established. The powder is obtained using inexpensive equipment, under stable production conditions, containing Fe as the main component, and having excellent pulverizability without deterioration of soft magnetic properties (mainly 4πIs). The purpose of the present invention is to provide shape-anisotropic soft magnetic alloy powder.

[Means for Solving the Problems] The present invention uses conventionally used general manufacturing equipment to produce a soft magnetic alloy powder containing Fe as a main component and having shape anisotropy at a low cost and in a stable manner. 1. An alloy ingot manufactured by a normal melting method,
The composition of the Fe-based alloy is adjusted so that it can be produced using equipment commonly used for pulverization, and this alloy powder contains Xwt% Si and Ywt% Co (x, y are.

4≦X≦27.1≦Y≦30, (7X-Y)/10≦
16) A ferromagnetic alloy powder in which the balance is substantially composed of Fe, and each powder particle is a plate-shaped particle, and is characterized by having an axis of easy magnetization in one direction parallel to the plate surface. .

In general, metal materials that are inexpensive and exhibit high magnetization characteristics are realized on the high Fe side, and have become industrially extremely useful functional materials. Therefore, the purpose of the present invention is to provide a ferromagnetic powder of 4π! The conditions were set such that the material has a property of 5 kG or more, and the raw material cost when Co is added does not exceed about twice the original raw material cost.

In the present invention, Si is Xwt% and Co is Ywt% (
X and Y are 4≦X≦27.1≦Y≦30.

(7X-Y)/10≦16) by pulverizing the containing alloy with conventionally used pulverizing equipment,
To make soft magnetic alloy powder having shape anisotropy at low cost without causing a decrease in 4πI.

It can be manufactured stably.

In the present invention, the Si content in Fe is set to 4 νt% or more because if it is less than this, the alloy ingot becomes viscous, and the improvement in pulverizability due to the addition of Co is small.

This is because it is impossible or difficult to crush using a general mechanical coarse crusher such as a show crusher. on the other hand,
The reason why the Si content is set to be 27 vt% or less is that in a region higher than this, the magnetization of 1 alloy powder is 5 kG or less in the range of Co addition of 11 to 30 vt%.

This is because the high magnetization characteristic of Fe-based alloys is significantly reduced. On the other hand, in the present invention, the Co content is set to 1wt% or more when 5ijfE4 to 27vt%
This is because when the amount of Co is in the range of 1vt% or more, it is expected that the pulverizability will be improved by adding Co.

Furthermore, in the present invention, the reason why the amount of Co is set to 30 wt% or less is that if more Co is added, the raw material cost will be more than twice the raw material cost when no Co is added, resulting in high cost. Also, in one aspect of the present invention.

5jvt% and Co vt 5'o (7XSivt
%-Cowt%)/10≦16 is set for Si and C.
If the o content exceeds this range, the magnetization of the alloy powder will decrease to 5k.
G or less, perhaps due to the high magnetization characteristic of Fe-based alloys.
This is because the amount decreases significantly.

In addition, in the present invention, the shape anisotropy of the powder is mainly achieved.

Coarsely crushed powder using a show crusher, etc.

This is achieved through a process of repeatedly applying relatively small mechanical stress using a ball mill or the like. The shape-anisotropic powder obtained here is generally plate-shaped.

Due to the demagnetizing field, the direction of the plate surface is the direction of easy magnetization.

This shape anisotropy occurs unless the ratio of the long axis/breadth axis of the particle is 1 (spherical). , the diameter can be easily adjusted within the range of about 1 to 5000 microns. - I tend to fish by boat.

Particles with improved flatness have a plate-like particle diameter of several tens of μ-
This is often achieved with a thickness of around 1 μm.

In the embodiments of the present invention described below, only pulverization and flattening using a show crusher and a rotary ball mill are described, but these are conventionally known pulverizers. Grinding using hammer mills, stamp mills, roll mills, etc.
It is self-evident that the effects of the alloy composition of the present invention can be seen even if a process is added or substituted for a machine that performs pulverization by energy transmission using balls, such as a vibrating mill, centrifugal mill, or planetary mill.

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

Example 1 Iron (Fe) and silicon (Si) with a purity of 99.8% or more
and cobalt (CO) in an argon atmosphere,
By high frequency heating, Si was heated to 3.4°, 5.6°, 8.10°,
15.20, 25.27vt%.

Co is 1.3.5.7.10.15.20.25°30
Ingot 9 with a thickness of about 2C) em with the balance Fe in wt%
0 types were produced.

Next, use a hammer to hammer these ingots.

It was crushed so that the largest long side was about 10 cm or less.

Next, the crushed pieces of these ingots were used to crush them using a commercially available show crusher (1w). The crushed ingot pieces were added one by one.

The results are shown in Table 1. In Table 1, an X mark means that it is impossible to crush the ingot, a Δ mark means that crushing is difficult but not impossible, an O mark means that crushing is fully possible, and a ◎ mark means that it is difficult to crush the ingot. can be easily crushed, and the O mark indicates a situation where it can be crushed extremely easily.

With Fe-5L-Co alloy as shown in Table 1.

Even in the low Si region, by containing Co at least 1vt%, it can be processed using a commercially available regular grinder.

Grinding becomes easy or extremely easy.

Table 1 with blank space below: Crushing test of Fe-5i-Co alloy ingot (
(by show crusher) ×: Impossible to crush △: l′ Difficult (not impossible) ○: ・I Possible ◎: Easy: Extremely easy Example 2 St obtained in Example 1 was 4.10 ．． ! 5゜20, 25
．． 27vt%・co is 1.5.10°15.20,25
, 30vt% balance of Fe, 42 types of coarsely ground powders were classified into 1 dragon or less, respectively.

Next, these powders were wet-ground in a ball mill using a stainless steel pole and ethanol. here.

By changing the stainless steel pole diameter, rotation speed, and operating time, the average diameter is approximately 30 to 50 μm.

The average thickness is 3~5μ layer, and the average diameter/thickness is about 7~
Each alloy powder consisting of 13 plate-shaped particles was obtained.

Next, add 2wt of liquid epoxy resin to these powders.
After mixing, the mixture was compressed in one direction using a mold at a pressure of about 500 kg/2 to obtain a compact of about 13 cubes.

The magnetic properties of this powder compact were measured in a direction parallel to the compression direction of the powder and in a direction perpendicular thereto.

The results are shown in FIG. In the figure, 4πIg is a value obtained by converting the powder occupancy rate to 100%. From the figure, 4zls≧
5kG or more, Si≦27vt%.

It can be seen that this is achieved within the range of (7XSiwt%-Covt%)/10≦16. In addition, regarding the magnetization characteristics depending on the direction of powder compression, the rise of the magnetization curve is steeper in the direction perpendicular to the direction of powder compression than in the direction parallel to the direction of powder compression.
H also shows a low value.

The I curve indicates that magnetization is easy in the direction perpendicular to the direction of powder compression.

A cross section of this compact was observed using a microscope.

The long axes of the plate-shaped alloy particles were aligned in a direction perpendicular to the direction of powder compression, forming a stacked state.

Therefore, it can be seen that the magnetization anisotropy characteristic of the powder compact is caused by the easy magnetization characteristic due to the shape of the powder.

[Effects of the Invention] As explained above, according to the present invention, a ferromagnetic alloy containing Fe as a main component can be produced by manufacturing an ingot and mechanically crushing it, which has been practiced for a long time and is said to be technically almost established. A shape-anisotropic soft magnetic alloy powder with Fe as the main component and excellent pulverizability without deterioration of soft magnetic properties can be obtained by using such inexpensive equipment and under stable manufacturing conditions. can be provided.

[Brief explanation of drawings]

FIG. 1 is in Example 1. FIG. 3 is a diagram showing the relationship between Co content and magnetic properties (4πl5IHC) of Fe-5i-Co alloy powder. The solid line in the figure is. The values measured in the direction perpendicular to the pressing direction are shown, and the broken lines represent the measured values in the direction horizontal to the pressing direction. Each town in the figure is 0:5wt%Si, 1~30wt%Co, balance Fe ()
: 10vt%St, 1-30vt%Co. Remaining Fe Δ: 15vt%Si, 1 to 30vt%Co. Remaining Fe: 20vt%Sj, 1-30vt%Co. Balance Fe Balance Fe G: 27vt%Si, 1-30vt%C. The balance shows Fe. For IHC, one typical value is 5νt%si. 1 to 30 wt% Co, balance Fe and 25 wt% Si. Only the measured values of 1 to 30 vt% Co and the balance Fe are shown. ◇: 25vt%Si, 1-30vt%Co.

Claims (1)

[Claims] 1. Si is Xwt%, Co is Ywt% (however, X=4~
27, Y = 1 to 30, (7X-Y)/10≦16) A ferromagnetic alloy powder in which the balance is essentially Fe, and each powder particle is a plate-shaped particle, with the particles parallel to the plate surface. A shape-anisotropic soft magnetic alloy powder characterized by having an axis of easy magnetization in one direction.