JPH03295205A - Anisotropic configuration soft magnetic alloy powder - Google Patents

Abstract

PURPOSE:To manufacture the soft magnetic alloy powder having anisotropic configuration at low cost in a stable manner by a method wherein the alloy, containing Si, B and Cr with specific contents in Fe, is crushed. CONSTITUTION:The title alloy powder is composed of Si of 3.0 to 23.0 (wt.%), B of 0.1 to 20.0 (wt.%), Cr of 0 to 30.8 (wt.%) (provided that X+Y>=3.1, X+Y+Z/2<=23.0 and Z=0 is not contained), and the rest part substantially consisting of iron. Each powder particle has the axis of easy magnetization in one direction in parallel with its plate surface.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a shape-anisotropic soft magnetic alloy powder used for core materials, magnetic head materials, etc., and more specifically, the present invention relates to a shape-anisotropic soft magnetic alloy powder used for core materials, magnetic head materials, etc. The present invention relates to a shape-anisotropic soft magnetic alloy powder that has improved soft magnetic properties in a specific direction by imparting shape anisotropy to metal powder.

[Prior Art] Conventionally, iron (Fe), which is inexpensive and has high magnetization, has been the most important substance in magnetic materials. Generally F
Metals containing a large amount of e exhibit soft magnetism that is easily magnetized. These soft magnetic alloys containing iron as a main component have generally been 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. In general, powders tend to have a smaller amount of magnetization per unit volume because the proportion of metal is smaller. In addition to that 2
As grain size increases, the influence of the demagnetizing field also increases, and the magnetization properties tend to deteriorate.

In order to alleviate these negative phenomena, it is useful to impart shape anisotropy to the powder so that it is magnetized only in a specific direction.

In general, soft magnetic alloys containing Fe as a main component are sticky.

It has been believed that conventional mechanical grinding methods cannot produce powder. Therefore, there are methods to obtain alloy particles by molten metal spraying method,
A method of manufacturing a ribbon using a liquid quenching method and then pulverizing it into an alloy powder, and a method of improving the non-grindability of one alloy by adding a metalloid element (e.g. B) in addition to Fe are two methods.
This is a general method for producing alloy powder containing a large amount of e.

[Problem to be solved by the invention] However, in the molten metal spraying method and the liquid quenching method.

It is necessary to introduce expensive equipment, the amount of processing is small, the stable manufacturing conditions are narrow, etc.

Metalloids that are effective in improving crushability in alloys (e.g.

In the method of adding boron (B), an increase in the amount added lowers the corrosion resistance of the alloy, which has many disadvantages as a soft magnetic material.

Therefore, one technical problem of the present invention is to eliminate these manufacturing defects by manufacturing and mechanically crushing ingots, which have been practiced for a long time and are said to be technically almost established.
This method obtains alloy powder mainly composed of Fe, using inexpensive equipment and under stable manufacturing conditions, adding Cr to Fe-5i-B alloy containing Fe mainly, which has excellent corrosion resistance, and The object of the present invention is to provide a shape-anisotropic soft magnetic alloy powder that is plate-shaped and has an axis of easy magnetization in one direction parallel to the plate surface.

[Means for Solving the Problem] 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 stably. 1 The composition of the Fe-based alloy is adjusted so that alloy ingots produced by normal melting methods can be produced using equipment commonly used for crushing. Si 3.0-23.0 (vt%), B 0.1-20.0
(vt%) Cr from 0 to 39.8 (vt%) (however,
+Y≧3.1, X+Y+Z/2≦23.0.
(excluding Z-0) ferromagnetic powder, the remainder of which is essentially iron, and each powder particle is plate-shaped and has an axis of easy magnetization in one direction parallel to the plate surface. do.

In general, Fe-based alloys include some alloys (e.g. Fe-Co
The higher the Fe content, the higher the magnetization tends to be. Therefore, a metal material exhibiting high magnetization characteristics at low cost can be realized on the high Fe side, and has become an industrially extremely useful functional material. Therefore, since the purpose of the present invention is to provide a ferromagnetic powder, it is set as a condition that the powder has a saturation magnetization of 4πI of 5 kG or more.

In the present invention, 3.0 to 23.0 (wt%) Si in Fe is
).

B from 0.1 to 20. (1 (wt%), Cr from 0 to 39.
8 (wt%) (Tax x y≧3.1, X+Y+Z
/2≦23.0Z-0) by pulverizing the alloy with conventionally used pulverizing equipment.

Soft magnetic alloy powder having shape anisotropy can be produced stably at low cost.

The Cr content in Fe was set to Ovt% or more (however, 0 is included) by adding Cr.

This is because the corrosion resistance of the alloy powder is significantly improved.

In addition, the Si content is X (νt%) and the B content is Y (ν[
%), and X=3. OwL% or more, Y=0. lvt% or more, X + Y = 3.1wt% or more, because if it is less than this, the alloy ingot becomes sticky and general mechanical crushing using a show crusher or the like becomes impossible or difficult. Also, X = 23.0wt% or less, Y
= 20.0wt% or less, Z -39.8wt% or less, X+ Y + Z / 2-23.0νt% or less because in the above range, the magnetization of 1 alloy powder is 5kG
It becomes below.

This is because the high magnetization characteristic characteristic of Fe-based alloys will be significantly reduced.

In addition, the shape anisotropy of the powder is mainly achieved by a process of repeatedly applying relatively small mechanical stress to the powder coarsely ground using a jaw cranone jar or the like using a ball mill or the like.

The shape-anisotropic powder obtained here is generally plate-shaped, and the direction of the plate surface is the direction of easy magnetization due to the relationship with the demagnetizing field. This shape anisotropy occurs unless the major axis/minor axis of one particle is 1 (spherical), and in the present invention,
The thickness of the plate-shaped particles is about 0.1 to 1000μ1. The diameter is about 1
Adjustment within the range of ~5000 μl can be easily carried out. −
As a general rule, particles with improved flatness are often achieved when the diameter of plate-like particles is several tens of microns and the thickness is around 1 micron.

In the following embodiments of the present invention, only pulverization and flattening using a show crusher and a rotary ball mill are described, but pulverization using conventional pulverizers such as hammer mills, stamp mills, and roll mills, vibrating mills, etc.
It is self-evident that the effects of the alloy composition of the present invention can be obtained even by adding or substituting a process using a model of a centrifugal mill, an a-star mill, etc., which grinds by energy transmission through poles.

[Embodiments] Two embodiments of the present invention will be described below with reference to the drawings.

Implementation @1 Iron (Fe), silicon (Si) with a purity of 99.8% or more,
Using boron (B) and chromium (Cr) in an argon atmosphere by high frequency heating.

Sl is 3.0.10.0.15.0.20.0.23.
0 (wt%).

B is 0. 0.1. 1.0.5.0.10.0.15
．． 0.20.0 (wt%), Cr is 0. 1.0.5.
0.10.0.15.0°20.0.25.0.30.
0.35.0.40.0 (vt%), balance Fe (wt
96 types of ingots each having a thickness of about 20%) were produced.

Next, use a hammer to hammer these ingots.

It was classified so that the maximum long side was about 10 ann or less.

Next, using the crushed pieces of these ingots, coarsely crushed powder of 1 mm or less was produced using a commercially available show crusher (I HP).

Next, these powders were wet ball milled using a stainless steel pole and ethanol. Here, by changing the stainless steel pole diameter, rotation speed, and operating time, the average diameter is about 30 to 50μ■, and the average thickness is 3 to 5μ.
An alloy powder consisting of plate-shaped particles having an average diameter/thickness ratio value of approximately 7 to 13 in l was obtained.

Next, add about 2w of liquid epoxy resin to these powders.
After mixing by t%, using a mold, approximately 500 kg/cd
The powder was compressed in one direction at a pressure of about 13III11 to obtain a green compact of about 13III11 cubes.

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

The results are shown in FIGS. 1 and 2. In the figure, 4π■ is the value of the heavy chain ratio of the powder converted to 100%.

Furthermore, regarding the magnetization characteristics depending on the powder compression direction, the magnetization curve rises steeply in the direction perpendicular to the powder compression direction compared to the direction parallel to the powder compression direction, and the HC also shows a low value. This 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 ease of magnetization due to the shape of the powder.

Figures 3 and 4 show the 4πI values of the samples.

With respect to Bffi and Cr amount. It is shown as a contour map of magnetic properties.

From the figure, 4πl ≧5kG is Si+B+Cr/2≦23
It can be seen that this can be achieved within the range of .

Example 2 Si obtained in Example 1 was 3.0.23.0 (wt
%) B is 0.1.20.0 (wt%), Cr is 0.
1. 13 kinds of ball milled powders of 1.0.0.5° + 0.0.15.0 (vt%) balance Fe (wt%) were heated in a constant temperature and humidity environment of 80°C and 95% humidity. 10
Hold for 00 hours.

Changes in the magnetic properties of the powder were measured. Changes in magnetic properties are
In the same manner as in Example 2, the epoxy resin was mixed and then pressure wire molded,
The magnetic properties of this green compact in the direction perpendicular to the pressing direction were measured.

The results are shown in FIG.

Powders without Cr added were held for 1000 hours.

Although the decrease in 4πl is significant and the deterioration of magnetic properties due to oxidation is clearly seen, by adding Cr, 1
The deterioration of magnetization characteristics after holding for 000 hours was significantly improved.

From this result, it can be seen that the single alloy powder has extremely excellent corrosion resistance.

Example 3 Obtained in Example 1. Si is 3.0.23.0 (v
t%) B is 0, 0.1.20.0 (vt%), C
“is 1.0.5.0°10.0.20.0.30.0.
Table 1 shows the results of crushing 24 types of broken pieces of ingots with a balance of Fe (wt%) of 40.0 (wt%) using a show crusher (IHP). In Table 1,
The X mark indicates that the ingot cannot be crushed, the O mark indicates that the ingot can be sufficiently crushed, and the O mark indicates that the ingot can be crushed extremely easily.

In Fe-5i-B-Cr alloy, Si is X (wt%), B
Let be Y (vt%) and X=3. Ovt% or more, Y-o, t
By containing vt% or more, x+y≧3.1 wt%, by using a commercially available ordinary pulverizer.

Sufficient pulverization is possible.

Margin Table 1 It can be manufactured by ingot manufacturing and mechanical crushing, which are said to be almost established.

A ferromagnetic powder containing Fe as a main component can be provided. Therefore, according to the present invention, inexpensive equipment is used.

Fe-5i-B with Fe as the main component under stable manufacturing conditions
By adding Cr to the alloy, it is possible to provide a shape-anisotropic soft magnetic alloy powder that has excellent corrosion resistance, is plate-shaped, and has an axis of easy magnetization in one direction parallel to the plate surface.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between Si, B, and Cr contents and magnetic properties (4πl) of Fe-5i-BCr alloy powder in Example 1. The solid line in the figure indicates the measured value in the direction perpendicular to the pressurizing direction. The 6 marks in the figure are 0:3. Owt%S i, 0.1 wt%B, 0
~40wt%Cr, balance Fe △: 1O, Owt%Si, 0.1w
t9o, B, 0 to 35 wt% Cr, balance Fe: 15. Ow1%S i , 0.1 w
t96B, O~2 5wt% Cr, balance Fe Mouth: 23. Owt%S i O, 1vt96 B
O~5vt%Cr, balance Fe Mu: 3. Ovt%S i , 10. Ov
t%B, 0 to 25vt%Cr, balance Fe ■3. Owt9ci S i , 20.
0 wt% B, 0-5 wt 9ciCr, balance Fe. FIG. 2 is in Example 1. It is a figure showing the relationship between Si, B, Cr contents and magnetic properties (, Ho) of Fe-5i-BCr alloy powder. The solid line in the figure indicates the measured value in the direction perpendicular to the pressurizing direction, and the broken line indicates the measured value in the direction parallel to the pressurizing direction. The 6 marks in the figure are 0:3. Owt%S i, 0.1 vt%B, 0
~40vt%Cr, balance Fe: 15. Ovt%Si, 0.1 wt
%B, 0-35vt%Cr, balance Fe Mu: 3. Owt%S i , 10. Owt
%B, 0-25wt%Cr, balance Fe ■2 3. Owt % S i , 20.
Owt% B, 0 to 5wt% Cr, balance Fe. 3 and 4 are Fe-8i-B-C in Example 1.
FIG. 3 is a diagram showing contour lines of magnetic properties (4πl) with respect to Si content, B content, and Cr content of r alloy. The O mark in the figure indicates the composition point of the measured sample, and the subscript indicates the measured value (4πI). The solid line in the figure is 4πI −
5kG contour lines are shown. FIG. 5 is in Example 2. FIG. 3 is a diagram showing the relationship between the amount of Cr and the change in magnetic properties (4πI) after holding Fe-3i-B-Cr alloy powder at constant temperature and constant humidity for 1000 hours. The 6 marks in the figure are 0:3. Owt%Si, o, tv
t%B. Cr, balance Fe △: 23. Owt%S i, o, i w
t%B. Cr, balance Fe Mouth: 3. Ovt%S i , 20. Owt%B. It shows Cr and the balance is Fe. 0~15ν196 0~10wt% 0~10vt% Fig. 2z Cr amount Cr amount (wt %) Fig. 3 X Si amount (wt・mu) Y°8 amount (Wzem)

Claims (1)

[Claims] 1. Si is Xwt%, B is Ywt%. Cr is Zwt% (
However, X=3.0~23.0, Y=0.1~20.0,
Z=0 to 39.8 (not including Z=0), X+Y≧3.1
, X+Y+Z/2≦23.0), a ferromagnetic alloy powder in which the remainder is substantially composed of Fe, each powder particle being a plate-shaped particle with an axis of easy magnetization in one direction parallel to the plate surface. A soft magnetic alloy powder with shape anisotropy.