KR20030015453A - An Electromagnetic Wave Attenuating Material Using The Scale Of Alloy Steel - Google Patents

Abstract

PURPOSE: An electromagnetic wave attenuating material in which oxides that are naturally generated during hot working of the alloy steel to be disused are processed to appropriately absorb or shield electromagnetic waves is provided. CONSTITUTION: The electromagnetic wave attenuating material is manufactured by milling scale produced during working of alloy steel and separated from the alloy steel into powder, wherein the alloy steel comprises one or more elements selected from 4 to 18 wt.% of chromium, 2 to 10 wt.% of nickel, 0.1 to 2 wt.% of silicon and 0.2 to 5 wt.% of manganese as a ratio for iron, the scale is an oxide comprising 10 wt.% or more of Maghemite that is quasi-stable crystal phase, and the electromagnetic wave attenuating material is powder that is prepared by milling the scale along with the conductive metal after adding 5 to 40 wt.% of conductive metal for the total weight to the scale.

Description

An Electromagnetic Wave Attenuating Material Using The Scale Of Alloy Steel}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electromagnetic wave damping materials using a scale of alloy steel, and more particularly, electromagnetic waves processed to be suitable for absorbing or shielding electromagnetic waves of oxides which are naturally generated and disposed of during the hot processing of alloy steel. It relates to the damping material.

Today, electrical and electronic equipment is an indispensable tool in modern people's lives, from personally owned cell phones to special purpose military equipment. While useful and necessary, almost all electrical and electronic devices emit electromagnetic waves that are known to be harmful to the human body. Therefore, studies on electromagnetic wave attenuation including absorption and shielding of electromagnetic waves are being actively conducted.

The study of electromagnetic damping is focused on the development of damping materials. The damping material of electromagnetic waves can be divided into two functional characteristics: absorption or shielding. In order to absorb electromagnetic waves, a material having excellent soft magnetic properties is required, and a material having high electrical conductivity is required for shielding. That is, when they have the same thickness, the absorption performance is better the higher the permeability and the smaller the coercive force, the better the blocking performance the greater the electrical conductivity.

The electromagnetic wave absorbing material currently applied generally is a metal oxide. Metal oxides are processed into powder and are mainly used for the purpose of absorbing electromagnetic waves. Many researches and developments are being conducted to improve magnetic properties and to make powders finer. As the shielding material, powder such as silver or copper having excellent electrical conductivity is used. Efforts have been made to obtain fine powders as well, since the finer the particles, the better the effect under the same weight.

Such metal oxide powder is usually added to a polymer or a ceramic material to obtain desired performance. In addition, in some cases, it is added to a liquid resin and used as a coating material. The electromagnetic wave damping material manufactured as described above is applied as a material for absorbing and shielding electromagnetic waves in various home appliances, electronic devices, wire covering materials, civil and military communication equipment, and the like.

However, the above-described conventional damping material of the electromagnetic wave has a problem in that the manufacturing cost is expensive because the powders included in the composition must be separately provided.

The present invention is to provide an electromagnetic wave damping material having a more economical compared to the electromagnetic wave damping material of the conventional metal oxide described above, to provide an electromagnetic wave absorbing and shielding material, that is, an electromagnetic wave damping material using a scale of alloy steel.

In addition, another object of the present invention is to provide an electromagnetic wave damping material processed by applying the electromagnetic wave damping material of the present invention described above.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a scanning electron microscope of an electromagnetic wave attenuating material of a first embodiment according to the present invention;

2A and 2B are graphs showing magnetic history curves of magnetic properties of the electromagnetic wave damping material of FIG. 1;

Figure 3 is a view of the electromagnetic wave damping material of a second embodiment according to the present invention with a scanning electron microscope;

4A and 4B are diagrams showing magnetic history curves of measuring magnetic characteristics of the electromagnetic wave damping material of FIG.

5 is a graph showing the results of an X-ray diffraction test on the scale of high alloy steel before grinding into powder.

Fig. 6 is a graph showing the X-ray diffraction test results for the electromagnetic wave attenuating material of the first embodiment of the present invention.

Fig. 7 is a graph showing the X-ray diffraction test results for the electromagnetic wave attenuating material according to the second embodiment of the present invention.

The electromagnetic wave damping material of the present invention having the above-mentioned object is a material produced during the processing of alloy steel and pulverized the scale separated from the alloy steel to be made of powder.

Here, the alloy steel includes one or more selected from chromium: 4% to 18%, nickel: 2% to 10%, silicon: 0.1% to 2%, and manganese: 02% to 5% by weight to iron.

In addition, the scale is an oxide containing 10% or more by weight of maghemite, a metastable crystal phase.

In addition, the electromagnetic wave damping material is a powder pulverized together by adding 5% to 40% by weight of the conductive metal to the scale.

The electromagnetic wave damping material having another object of the present invention is manufactured by including the electromagnetic wave damping material of the present invention described above, and includes a synthetic resin and the electromagnetic wave damping material impregnated in the synthetic resin, and is a paint or a predetermined molding.

In addition, the electromagnetic wave damping material of the present invention includes a ceramic and the electromagnetic wave damping material impregnated in the ceramic, and has a tile shape.

The electromagnetic wave damping material of the present invention is to obtain an electromagnetic wave damping material by crushing the scale of the alloy steel into a powder of a suitable size. The scale is an oxide produced on the surface of the metal material during the high temperature work of the metal material, and preferably the scale of the high alloy steel.

More specifically, the process of generating the above-described scale, when the high-alloy steel is subjected to plastic working at high temperature, a large amount of coolant is added to the surface of the high alloy steel, and accordingly quenching, an oxide scale is formed on the surface of the steel. It is produced in large quantities.

These scales are naturally removed from the surface of the high alloy steel, or removed or separated from the surface of the steel by an artificial method, such as by applying a strong jetting water, and are collected in a lower part of a processing machine such as a rolling mill.

Unlike the conventional waste treatment of the collected scales as described above, the present invention is to crush the scale into powder to utilize the electromagnetic wave damping material.

In addition, scales applied to the present invention include scales produced in slabs, ingots, billets, and the like of alloy steel, and the collecting method includes those that are naturally or artificially separated from the surface of the alloy steel as described above.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view of the electromagnetic wave damping material according to the first embodiment of the present invention with a scanning electron microscope, and FIGS. 2a and 2b are magnetic hysteresis curves measuring magnetic characteristics of the electromagnetic wave damping material of FIG.

As can be seen in Figure 1, the electromagnetic wave damping material of the first embodiment of the present invention is a high alloy steel, the weight ratio to iron, chromium: 4% to 18%, nickel: 2% to 10%, silicon: 0.1% To 2% and manganese: 02% to 5%. In addition, in order to have excellent damping ability, it is necessary to fill a wide surface with only a small amount of addition, and as shown, the long side of the powder surface exceeds about 100 micrometers even though the thickness of the powder is about 10 micrometers.

As can be seen from FIG. 2, the electromagnetic wave damping material of the first embodiment of the present invention has a low coercive force and a high permeability, and has the necessary characteristics as an absorbing material of electromagnetic waves.

FIG. 3 is a view of the electromagnetic wave damping material according to the second embodiment of the present invention with a scanning electron microscope, and FIGS. 4a and 4b are magnetic hysteresis curves measuring magnetic properties of the electromagnetic wave damping material of FIG.

As can be seen in Figure 3, the electromagnetic wave damping material of the second embodiment according to the present invention is added to the powder of the high-alloy steel scale of the first embodiment by adding a conductive metal, that is, 20% by weight of aluminum to the total weight in the appropriate conditions It was pulverized together, and the surface of the oxide powder having no electrical conductivity was surface treated by a physical method with a metal having excellent conductivity.

The powder of the electromagnetic wave damping material of another embodiment also maintains a shape almost similar to that of the powder of the first embodiment without surface treatment of the conductive metal. Of course, copper and silver may be applied as the conductive metal in addition to aluminum.

The electromagnetic wave attenuating material of the second embodiment of the present invention manufactured as described above has the electromagnetic wave absorbing ability as it is and the electromagnetic wave shielding ability is improved. It is important to note that the magnetic properties of the absorber should not deteriorate significantly during the surface treatment process. As can be seen from FIG. 4, the electromagnetic wave damping material of the second embodiment of the present invention is compared with the original characteristic value of the first embodiment. As a result, the coercivity is slightly larger and the permeability is slightly lower, but there is no significant change.

5 is a graph showing the results of an X-ray diffraction test on the scale of high alloy steel before grinding into powder.

Fig. 6 is a graph showing the X-ray diffraction test results for the electromagnetic wave attenuating material of the first embodiment of the present invention.

7 is a graph showing the X-ray diffraction test results for the electromagnetic wave attenuation material of the second embodiment of the present invention.

As can be seen in Figures 5 to 7, it can be seen that the crystallographic properties of the oxide scale do not change during the manufacturing process for the suitable use in the first and second embodiments of the present invention. That is, it can be seen that the stable phase hematite and the metastable maghemite exist together in the waste scale of the high alloy steel before grinding into the powder shown in FIG. 5. It can be seen that the same ratio is maintained in FIG. 6 and FIG.

In addition, the present invention can be used as an electromagnetic wave damping material such as a coating material, a film of a polymer material or a polymer molding material by impregnating the electromagnetic wave damping material of the first and second embodiments described above in a synthetic resin.

In addition, the electromagnetic wave damping materials of the first and second embodiments of the present invention may be impregnated into a synthetic resin having electrical conductivity, and thus may be used as electromagnetic wave damping materials such as paints, films of polymer materials, or polymer molding materials.

Furthermore, the electromagnetic wave damping material of the first and second embodiments of the present invention can be used as an electromagnetic wave damping material manufactured in the form of a tile by impregnating a ceramic or the like.

Those skilled in the art will appreciate that the electromagnetic wave damping material manufactured by applying the electromagnetic wave damping material of the present invention can be variously applied within the spirit and scope of the present invention.

The electromagnetic wave damping material of the present invention is economically effective by manufacturing the electromagnetic wave damping material by pulverizing to an appropriate size using the scale of the alloy steel which has been previously treated as waste as a raw material without separately purchasing the compositions used as the damping material.

Further, by adding a metal having electrical conductivity to the scale of the alloy steel and pulverizing it together, an electromagnetic wave damping material having the performance of absorbing and shielding electromagnetic waves can be provided.

Claims (7)

As a damping material of electromagnetic waves, Electromagnetic wave damping material produced during the processing of alloy steel and made of powder by grinding the scale separated from the alloy steel. The method of claim 1, wherein the alloy steel is a weight ratio to iron, at least one selected from chromium: 4% to 18%, nickel: 2% to 10%, silicon: 0.1% to 2% and manganese: 02% to 5% Electromagnetic wave damping material comprising a. The electromagnetic wave damping material according to claim 1 or 2, wherein the scale is an oxide containing 10% or more of maghemite, which is a metastable crystalline phase, by weight. The electromagnetic wave damping material of claim 1, wherein the electromagnetic wave damping material is a powder obtained by adding 5% to 40% of the conductive metal to the scale by a weight ratio of the whole. Electromagnetic wave damping material comprising the electromagnetic wave damping material of claim 1. The electromagnetic wave damping member according to claim 5, wherein the electromagnetic wave damping member comprises a synthetic resin and the electromagnetic wave damping material impregnated in the synthetic resin, and is a paint or a predetermined molding. The electromagnetic wave damping material of claim 5, wherein the electromagnetic wave damping material comprises a ceramic and the electromagnetic wave damping material impregnated in the ceramic, and has a tile shape.