KR102346665B1 - SiAlON-BASED MAGNETIC MATERIAL AND MANUFACTURING METHOD THEREOF - Google Patents

Abstract

The present invention relates to a sialon-based magnetic material indicated in the following chemical formula. In accordance with the present invention, a sialon-based magnetic material is doped with holmium (Ho) in place of transition metal elements (Fe, Co and the like), which are commonly used for doping to obtain existing magnetic ceramics, to have a net magnetic moment at a room temperature, and, as a result, the sialon-based magnetic material can be beneficially used as a material for various transformer cores, inductor cores, a head of a magnetic recording device or the like, and moreover, the material is expected to be expanded to various application fields in the future based on an advantage of having both a fluorescence characteristic and a magnetic characteristic. [Chemical formula] Hom/33+Si12-m-nAlm+nOnN16-n.

Description

SiAlON-based magnetic material and manufacturing method thereof

The present invention relates to a novel ceramic-based magnetic material and a method for manufacturing the same.

SiAlON (SiAlON) is a solid solution phase between oxides and nitrides of the Si-Al-ON system, developed in the 1970s by dissolving oxides such as alumina as a sintering aid for the sintering of _{β-silicon nitride (Si 3} N _{4 ).} As a ceramic material, the Si-N bond of β-silicon nitride replaced by Al-O bond is known as β-sialon, and _{is expressed by the general formula Si 6-z} Al _z O _z N _8-z , and α-sialon is Me -Si-Al-ON Another phase of sialon that is stabilized with metal (M) ions is known, and when α-sialon is ^{stabilized with M v+} ions, its general formula is expressed as M _m/v Si _12-mn Al _m+n O _n N _16-n .

These sialons have traditionally been widely applied in related fields because of their high hardness, excellent wear resistance, and excellent high-temperature strength and oxidation resistance. It is used as a material for members and cutting tools.

Furthermore, recently, research has been actively conducted to dope sialon with rare earth elements and apply it as a light emitting material for white LEDs, etc., and the need for expansion of application fields is increasing based on various and excellent physical properties of sialon. .

In particular, as the demand for materials related to the recent explosive growth of ICT-related industries has exploded, it is necessary to search for potential applications as electromagnetic materials.

Japanese Patent Application Laid-Open No. 2012-206934 (published date: October 25, 2012) Korean Patent Registration No. 10-1923311 (Registration Date: 2018.11.22.)

An object of the present invention is to provide a sialon-based magnetic material having magnetic properties by doping a specific element into sialon, which has been known only for use as a conventional structural material or a fluorescent material, and a method for manufacturing the same.

The present invention provides a sialon-based magnetic material represented by the following formula.

[Formula]

Ho _m/3 ³⁺ Si _12-mn Al _m+n O _n N _16-n .

The sialon-based magnetic material is characterized in that the saturation magnetization value is 0.33 emu/g or more.

And, in another aspect of the present invention, as a method for producing a sialon-based magnetic material represented by the above formula, (a) α-Si ₃ N ₄ powder, AlN powder, Al ₂ O ₃ powder and Ho ₂ O ₃ powder preparing a mixed powder of (b) preparing a compact by compressing the mixed powder; (c) performing gas pressure reaction sintering of the molded body in a reducing atmosphere at a temperature of 1700-1900° C. and a pressure of 25-30 MPa to prepare a sintered body; provides

In this case, the gas pressure reaction sintering of step (c) may be performed by hot press, gas pressure sintering, or hot isostatic press (HIP).

Furthermore, in another aspect of the present invention, various types of transformer cores, inductor cores, and magnetic recording device heads including the Sialon-based magnetic material represented by the above formula as a core magnetic material are provided.

The sialon-based magnetic material according to the present invention is doped with holmium (Ho) instead of the transition metal elements (Fe, Co, etc.) that are conventionally doped to obtain ceramics having magnetism, so that the net magnetic moment at room temperature is moment), it can be usefully used as a material for various transformer cores, inductor cores, and heads of magnetic recording devices. this is expected

1 shows Ho ³⁺ doped α-SiAlON specimens (H10, H11, H15 and H20) and Ho ³⁺ /Yb ³⁺ doped α-SiAlON specimens (HY05, HY10, HY15, HY20, HY25 and Y11)'s photo.
2 is a Ho ³⁺ doped α-SiAlON specimen (H10, H11, H15 and H20) and Ho ³⁺ /Yb ³⁺ doped α-SiAlON specimen (HY05, HY10, HY15, HY20, HY25 and Y11) is the result of XRD analysis.
3a is an electron density of states (DOS) obtained through first principles calculation for a HY15 specimen among ^{Ho 3+} -doped α-SiAlON specimens prepared in Examples of the present application.
3B is a projected density of states (PDOS) for each atom included in the HY15 specimen among ^{the Ho 3+} -doped α-SiAlON specimens prepared in Examples of the present application.
4 shows Ho ³⁺ doped α-SiAlON specimens (H10, H11, H15 and H20) and Ho ³⁺ /Yb ³⁺ doped α-SiAlON specimens (HY05, HY10, HY15, HY20, HY25 and Y11) is a hysteresis curve graph.

In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Since the embodiment according to the concept of the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the present specification or application. However, this is not intended to limit the embodiment according to the concept of the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, or substitutes included in the spirit and scope of the present invention.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "have" are intended to designate that the described feature, number, step, operation, component, part, or a combination thereof exists, and includes one or more other features or numbers. , it should be understood that it does not preclude the possibility of the existence or addition of steps, operations, components, parts, or combinations thereof.

Hereinafter, the present invention will be described in more detail by way of examples.

Embodiments according to the present specification may be modified in various other forms, and the scope of the present specification is not to be construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present specification to those of ordinary skill in the art.

<Example>

High purity α-Si ₃ N ₄ , AlN, Al ₂ O ₃ , Ho ₂ O ₃ and Yb ₂ O ₃ With Ho ³⁺ doped ^{α-SiAlON (Ho 3+ -α-} SiAlON) synthesis, and as a comparative example, Ho ³⁺ and Yb ³⁺ co-doped ^{α-SiAlON (Ho 3+ / Yb} 3+ -α-SiAlON) Fig. synthesized.

Specifically, according to Table 1 below, α-Si ₃ N ₄ powder, AlN powder, Al ₂ O ₃ powder, Ho ₂ O ₃ powder, and Yb ₂ O ₃ powder were mixed with high-purity α-Si ₃ N ₄ balls and in ethanol. After ball milling to prepare a slurry, it was dried to prepare a mixed powder. Then, after uniaxial pressure molding of the mixed powder to prepare a molded article, the molded article was subjected to a hot press for 2 hours at a temperature of 1850° C. and a pressure of 30 MPa in a nitrogen atmosphere, as shown in FIG. 1 . Ho ³⁺ -doped α-SiAlON specimens (H10, H11, H15 and H20) and Ho ³⁺ /Yb ³⁺ doped α-SiAlON specimens (HY05, HY10, HY15, HY20, HY25 and Y11) were prepared and each polished, cut and mirror polishing.

<Table 1> Ho ³⁺ -α-SiAlON and Ho ³⁺ /Yb ³⁺ -Chemical composition of α-SiAlON specimens

The results of XRD analysis of each of the specimens prepared above are shown in FIG. 2 . Referring to FIG. 2 , it was confirmed that the main crystalline phase in all the specimens was α-sialon, and it was confirmed that a small amount of β-sialon was included depending on the specimen. In addition, it seems that the lattice constant of α-sialon crystals decreases due ^{to Ho 3+} doping because the position of the (210) plane peak of α-sialon shifts to the left as the doping amount increases.

3a is an electron density of states obtained by considering an electron spin through first principles calculation for a HY15 specimen among ^{the Ho 3+} doped α-SiAlON specimens prepared in Examples of the present application; FIG. DOS).

Referring to FIG. 3a, it can be seen that the HY15 specimen made of α-SiAlON doped with ^{Ho 3+} has magnetism because the shapes of DOS for up spin and DOS for down spin are different. can

3B is a projected density of states (PDOS) for each element included in the HY15 specimen among ^{the Ho 3+} -doped α-SiAlON specimens prepared in Examples of the present application.

It can be seen from the PDOS of Fig. 3b that the magnetism of the HY15 specimen originates from which orbital. Unlike other elements, the PDOS of Ho exhibits an asymmetric spin density, suggesting that the magnetism of the HY15 specimen is due to Ho doping.

4 shows a graph of a hysteresis curve measured at room temperature using a vibrating sample magnetometer (VSM) for ^{the Ho 3+} -α-SiAlON specimen and the Ho ³⁺ /Yb ³⁺ -α-SiAlON specimen prepared in this Example. did.

In addition, Table 2 below describes the measured values of the magnetic properties parameter at room temperature of the ^{Ho 3+} -α-SiAlON specimen and the Ho ³⁺ /Yb ^{3+ -α-SiAlON specimen prepared in this Example.}

4 and Table 2, it can be seen that the specimens prepared in this example exhibit paramagnetic behavior, and the saturation magnetization value of the ^{Ho 3+ -α-SiAlON specimen is Ho 3+} /Yb ³⁺ -α- It is higher than the saturation magnetization value of the SiAlON specimen, and in the Ho ³⁺ -α-SiAlON specimens, the saturation magnetization value also increases as the ^{Ho 3+ -doping amount increases.}

<Table 2> Ho ³⁺ -α-SiAlON and Ho ³⁺ /Yb ³⁺ Magnetic properties of -α-SiAlON at room temperature

The present invention is not limited to the above embodiments, but can be manufactured in a variety of different forms, and those of ordinary skill in the art to which the present invention pertains can take other specific forms without changing the technical spirit or essential features of the present invention. It will be understood that it can be implemented as Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (5)

A sialon-based magnetic material represented by the following formula:
[Formula]
Ho _m/3 ³⁺ Si _12-mn Al _m+n O _n N _16-n (m=2.0, n=1.0). delete (a) preparing a mixed powder of _{α-Si 3} N ₄ powder, AlN powder, Al ₂ O ₃ powder, and Ho ₂ O _{3 powder;}
(b) preparing a compact by compressing the mixed powder;
(c) performing gas pressure reaction sintering in a reducing atmosphere at a temperature of 1700-1900° C. and a pressure of 25-30 MPa to prepare a sintered body; including,
A method for producing a sialon-based magnetic material represented by the following formula:
[Formula]
Ho _m/3 ³⁺ Si _12-mn Al _m+n O _n N _16-n (m=2.0, n=1.0). 4. The method of claim 3,
The gas pressure reaction sintering of step (c) is a sialon-based magnetic material, characterized in that it is performed by hot press, gas pressure sintering, or hot isostatic press (HIP). Way. A magnetic component comprising the sialon-based magnetic material of claim 1.

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