JPH0413801A - Manufacture of high flattened powder - Google Patents

Abstract

PURPOSE:To manufacture metal powder having high flattened shape anisotropy and excellent magnetizing characteristic by rolling iron-series magnetic metal powder and treating with a pulverizer using balls and rods as medium body after making this powder low flattened powder. CONSTITUTION:As the iron powder pulverized with atomizing method or mechanical method, has the shape near spherical and has poor magnetic characteristic, once the rolling treatment is executed and this is plastic-deformed into the shape having comparatively low flattened shape of >=2 the flattening degree (long diameter/short diameter ratio). This powdery iron powder is pulverized under wetting condition with the pulverizer of ball mill, etc., using steel balls or steel-made rods as pulverizing medium, and by making the iron powder having high flattened shape of 2 - 80 the flattening degree, the flattened iron powder having easy magnetization with this shape anisotropy is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a shape-anisotropic powder which is a plastically deformable powder containing iron as a main component.

[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 allows easy magnetization. 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,
Since the proportion of metal in the powder decreases, the amount of magnetization per unit volume tends to decrease. 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 would be useful to provide powder with shape anisotropy to facilitate magnetization only in a specific direction.

[Problems to be Solved by the Invention] However, in general, soft magnetic alloys containing Fe as a main component are sticky and cannot be easily pulverized by ordinary mechanical pulverization methods. Therefore, common manufacturing methods include a molten metal spraying method (atomization method) and a method of manufacturing a ribbon using a liquid quenching method and then pulverizing it into an alloy powder. The powder produced by the former method has a spherical shape and cannot be flattened easily in a pulverizer that uses balls or rods as a medium, which are generally used for fine pulverization. On the other hand, the latter method is obtained by crushing a thin ribbon because the alloy has toughness.

It is difficult to crush.

Therefore, the technical problem of the present invention relates to the flattening of powder made of particles with low flatness (the major axis of the particle/the minor axis of the particle is close to 1) produced by the atomization method or the boat fishing crushing method. , these plastically deformable powders containing Fe as the main component can be easily made highly flattened using a commonly used crusher using bolts or rods as media, and magnetically produced shape anisotropy at low cost. An object of the present invention is to provide a method for producing a powder exhibiting the following properties.

[Means to solve the problem] According to the present invention, the input powder is mainly composed of iron.

In the method of producing a highly flattened powder by plastic deformation by a crushing means, the flatness of the particles of the input powder (major axis dimension of particle / minor axis dimension of particle) is substantially 2 or more. A method for producing a characteristically high flatness powder is obtained.

According to the present invention, there is obtained a method for producing a highly flattened powder, characterized in that the input powder is subjected to a rolling treatment.

That is, one aspect of the present invention is to obtain high flatness powder from low flatness powder using a commonly used pulverizer using balls or rods as media. Due to this high flattening, F
Since a metal containing e as a main component has improved shape anisotropy, it exhibits high soft magnetic properties in a specific direction (generally, the major axis direction).

Usually, a crusher using balls or rods as a medium is used to
When powder consisting of spherical particles is flattened, the component and probability of the stress transmitted from the grinding medium contributing to the direction of size reduction of one particle becomes extremely small. Therefore, not only is it difficult to flatten the powder, but also the variation in flatness becomes large.

As a result of various studies, the inventor of the present invention found that flattening can be promoted by using powder rolled with a roll or press.

When powder consisting of these flattened particles is used in the above-mentioned pulverizer, the stress transmitted from the medium contributes most to the direction of decrease in the thickness of the particles.

Flattening improvement is promoted.

The flatness of the powder fed into the pulverizer is preferably 2 or more.

This is because when the flatness is 2 or more, the effect of improving the flatness after the crusher treatment becomes significant.

Incidentally, the flatness shown here is expressed as the major axis of one particle/the minor axis of the particle, and the flatness of the powder is the average value of these particles. The dimensions of these particles were determined using scanning electron microscopy and optical microscopy.
It is obtained from the particles of ke. For example, in the case of a powder consisting of particles that are almost perfectly spherical, the oblateness is approximately 1, and in the case of a powder with an average diameter of 50 μm and a thickness of 1 μm, the oblateness is 50.

As can be seen from the above description, flattening in the present invention is due to plastic deformation.

The object must have that property. Furthermore, since this is a pulverizer with a mechanism in which stress is randomly transmitted to the powder particles from the thickness direction, the flattened particles usually have a shape similar to a disk.

[Example] Next, one embodiment of the present invention will be described.

Example 1 Alloy plasticization consists of Si 8.5 sit%, balance Fe and St 11w
A powder containing t% balance Fe was produced by a water atomization method. The particles of this powder are Fe-8,5% powder of 500 to 1
00φpttr, Fe-11% powder is 300~50φ
The μ mark accounted for more than 90%, and it was spherical (flatness of about 1).

Next, this powder is rolled with a roll so that the degree of flatness is 1.
The powder consisted of flat particles of 2, 3, 4, 5, and 6.10.

Next, a rotary ball mill using Cr steel balls of about 15 φ as a grinding medium was used, and processing was carried out for 50 hours. These treated powders consisted of disc-shaped particles with an oblateness of 2 to 80.

The results are shown in FIG. In the region where the flatness of the powder input to the rotary ball mill is 2 or more.

Flattening is progressing significantly.

Example 2 A powder consisting of pure iron and 78% Ni with the balance being Fe was produced by a water atomization method. The particles of this powder are 500 to 100φμ
m accounted for 90% or more, and the shape was roughly spherical (1 in terms of oblateness).

Next, this powder is rolled with a roll so that the degree of flatness is 1.
The powder consisted of flat particles of 2, 3, 4, 5, and 6.10.

Next, using a vibrating rod mill using a stainless steel rod of about 10φmm x 3001+nm as a grinding medium,
0 o'clock time type processing was performed. These treated powders have an oblateness of 3~
It consisted of 100 disk-shaped particles.

The results are shown in FIG. In the region where the flatness of the powder input to the vibrating rod mill treatment is 2 or more.

Flattening is progressing significantly.

As can be seen from the above examples, when flattening powder using a pulverizer that uses balls or rods as the crushing media, by setting the flatness of the input powder to 2 or more, it is possible to The flatness is significantly improved.

Also, in this embodiment, it is used as a fine grinder.

Although it only talks about rotary mills and vibrating mills.

It is clear that similar effects can be expected even if the grinding medium is of a different type, such as a planetary mill or a stirring mill, as long as it is spherical or rod-shaped.

In addition, the composition of the treated powder is pure iron, Fe-6゜5%
Although only St, Fe-11%Si, and Ni78%-Fe have been described, the effects of the present invention are not limited to these components, and can be applied to any material that can be plastically deformed. It is clear that

In addition, 1. In the present invention, only atomized powder has been described, but even powders produced by other manufacturing methods are within the scope of the present invention as long as they are capable of plastic deformation and have an oblateness of less than 2. That is clear.

[Effects of the Invention] As explained above, 8 According to the present invention, 1. Fe-containing powder with a high degree of flatness can be easily produced using an ordinary pulverizer.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the flatness of the input powder and the processed powder in the rotary ball mill treatment in Example 1. In the figure, ○ mark is Fe-8,5%Si powder, △ is F
Represents e-11% Si powder. FIG. 2 is a diagram showing the relationship between the flatness of the input powder and the processed powder in the vibrating rod mill treatment in Example 2. In the figure, ○ mark is pure iron powder, Δ mark is Ni '78%-N1
It represents powder.

Claims (1)

[Scope of Claims] 1) A method for producing a highly flattened powder by plastically deforming an input powder containing iron as a main component using a crushing means, wherein the flatness of the particles of the input powder (the major axis dimension of the particle /breadth dimension of particles) is substantially 2 or more. 2) A method for producing highly flattened powder according to claim 1, wherein the charged powder is subjected to a rolling process.