KR101355542B1 - Ceramic composite and preparing method of the same - Google Patents

Abstract

The present application relates to a ceramic composite material and a method for manufacturing the same, comprising a sintered body containing different ceramic components and having uniformly dispersed different ceramic particles having different particle sizes.

Description

Ceramic composite material and manufacturing method thereof {CERAMIC COMPOSITE AND PREPARING METHOD OF THE SAME}

The present application relates to a ceramic composite material and a manufacturing method thereof.

As the advanced electronic industry develops gradually in the modern society, as the miniaturization, digitalization, high speed, and versatility of electronic devices are progressing, semiconductors and mobiles are rapidly becoming highly integrated and high output. By such a flow, the mounting substrate of an element is also required to have high thermal conductivity.

In general, an insulating substrate material is required to have high insulation, low dielectric constant and low dielectric loss, high thermal conductivity, and chemical stability. For this reason, oxides such as alumina (Al ₂ O ₃ ), beryllium oxide (BeO), forsterite (2MgOSiO ₂ ), and nitrides such as aluminum nitride (AlN) and silicon nitride (SiN) having relatively similar properties It is mainly used for this board | substrate. However, since most of the substrate materials are expensive materials and limited in industrial use, studies are being actively conducted to improve the properties of low-cost materials such as alumina.

Alumina is one of the key materials representing ceramics and is one of the key materials in the IC substrate material market. Alumina is widely used as a substrate material because it is not only an excellent insulator electrically but also an excellent mechanical property as a substrate material. However, as the integration and speed of circuits are increased due to the miniaturization and multifunctionalization of electronic devices, development of materials having excellent heat dissipation characteristics capable of withstanding high heat dissipation of circuits is being investigated.

Accordingly, the use of oxide-based Beryllia (BeO) and carbon-based alumina, silicon carbide (SiC) and crystalline silicon, which have high thermal conductivity (260 W / m · K), has been considered. In the case of Beryllia, it has been spotlighted as a key material to replace alumina because of its excellent characteristics as a substrate material, but the powder is not only toxic to the human body but also economical in the manufacturing process. Its use is restricted to local parts. On the other hand, silicon carbide has attracted attention due to its high thermal conductivity (240-270 W / mK), but it is insufficient in terms of insulation as a semiconductor, and is known to interfere with electric signal transmission due to its high dielectric constant. Limited.

On the other hand, aluminum nitride is mainly used as a high thermal conductivity insulating material as a substrate material due to high thermal conductivity, insulation and dielectric properties. In addition, alternative materials such as in-vehicle thyristors or ignition modules and LED diodes are mainly used together with gallium nitride (GaN). However, despite these excellent properties, aluminum nitride sintered bodies are very expensive due to the incombustibility problem of aluminum nitride itself. Therefore, in order to solve the sintering ability and lower the sintering temperature, the solution is sought through the addition and doping of yttria (Y ₂ O ₃ ), but it is not yet completely replaced by economically high price compared to alumina. to be.

Accordingly, there is an urgent need for the development of an easy and economical process for producing materials suitable for high-integrated circuits and LED substrates through a combination of the economical utility and excellent properties of alumina and the high thermal conductivity of aluminum nitride.

Korean Patent No. 10-0721780 discloses a composite material having an ultrafine nanostructure having a grain size of aluminum or aluminum alloy matrix and an aluminum nitride reinforced phase of 10 μm or less. In No. 10-0721780, in order to manufacture the composite material, after the mechanical milling / alloying step in a nitriding induction atmosphere, an aluminum / aluminum nitride or aluminum alloy / aluminum nitride composite powder is prepared using a heat treatment process for forming Al / AlN. The composite powder is finally hot-molded to produce a high-strength metal molded body.

The present invention includes a sintered body containing different ceramic components and having uniformly dispersed different ceramic particles having different particle sizes, wherein secondary phase formation is reduced or secondary phase formation between the different ceramic particles is reduced. To provide a ceramic composite material and a method for producing the ceramic composite material.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

A first aspect of the present application provides a ceramic composite material, which comprises a sintered body containing different ceramic components from one another and uniformly dispersed different ceramic particles having different particle sizes from each other.

A second aspect of the present application provides a method of making the ceramic composite material according to the first aspect of the present application, comprising:

(a) adjusting the particle size of each of the different ceramic particles containing different ceramic components;

(b) dispersing and mixing the particle size controlled ceramics in a solvent to form a slurry;

(c) removing the solvent from the slurry to form a ceramic composite powder; And

(d) sintering the ceramic composite powder to form a ceramic composite material.

According to the above-described problem solving means of the present invention, as a sintered body containing different ceramic components and uniformly dispersed different ceramic particles having different particle sizes, secondary phase formation between the different ceramic particles It is possible to provide a ceramic composite material, either reduced or without secondary phase formation. Specifically, in the ceramic composite material according to the present application, by reducing the secondary phase formation or no secondary phase formation between the different ceramic particles, it is possible to improve the electrical and / or thermal properties of the ceramic composite material. .

1 is a schematic view showing the structure of a ceramic composite material according to one embodiment of the present application.
2 is a flowchart illustrating a method of manufacturing a ceramic composite material according to one embodiment of the present application.
3 is a scanning electron microscope of each ceramic composite material including (a) aluminum nitride powder, (b) alumina powder, and (c) uniformly dispersed aluminum nitride particles and alumina particles according to an embodiment of the present disclosure. Electron Microscope = SEM).
Figure 4 is a schematic diagram showing a change in the phase (phase) appearing as the sintering process in the method of manufacturing a ceramic composite material according to an embodiment of the present application.
5 is an XRD spectrum of a ceramic composite material according to one embodiment of the present application.
Figure 6 is a graph showing the EDX analysis using STEM photographs and TEM for secondary phase analysis during the manufacture of a ceramic composite material according to an embodiment of the present application.
7 is a graph showing the thermal conductivity and the electrical conductivity of the ceramic composite material according to an embodiment of the present application.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is "directly connected" but also includes the case where it is "electrically connected" do.

Throughout this specification, when a member is " on " another member, it includes not only when the member is in contact with the other member, but also when there is another member between the two members.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. The terms "about "," substantially ", etc. used to the extent that they are used throughout the specification are intended to be taken to mean the approximation of the manufacturing and material tolerances inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure. The word " step (or step) "or" step "used to the extent that it is used throughout the specification does not mean" step for.

Throughout this specification, the term “combination of these” included in the expression of the makushi form means one or more mixtures or combinations selected from the group consisting of the constituents described in the expression of the makushi form, wherein the constituents It means to include one or more selected from the group consisting of.

The ceramic composite material according to the first aspect of the present disclosure may include, but is not limited to, a sintered body containing different ceramic components and having different ceramic particles uniformly dispersed therein.

In one embodiment of the present invention, the ceramic composite material, the secondary particle formation between the different ceramic particles is reduced by sintering by controlling the particle size of the different ceramic particles differently from each other in a specific ratio range or There may be no secondary phase formation, but is not limited thereto.

According to one embodiment of the present application, each of the ceramic particles may include a ceramic component selected from the group consisting of oxides, carbides, nitrides, borides, and combinations thereof, but is not limited thereto. When the ceramic components are mixed with each other and sintered without controlling the particle sizes differently from each other as in the prior art, secondary phases are formed between the different ceramic particles to have limited electrical / thermal properties.

The nitride may include, for example, one or more selected from the group consisting of TiN, ZrN, HfN, VN, NbN, TaN, and combinations thereof, but is not limited thereto.

For example, the oxide may include one or more selected from the group consisting of SiO ₂ , TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , MgO, BeO, and combinations thereof, but is not limited thereto.

The carbide may include, for example, at least one selected from the group consisting of SiC, TiC, ZrC, HfC, VC, NbC, TaC, Mo ₂ C, WC, and combinations thereof, but is not limited thereto. no.

The boride may include, for example, one or more selected from the group consisting of TiB ₂ , ZrB ₂ , HfB ₂ , VB ₂ , NbB ₂ , TaB ₂ , WB ₂ , MoB _2, and combinations thereof. However, the present invention is not limited thereto.

According to one embodiment of the present disclosure, each of the different ceramic particles may have a particle size of about 1 nm to about 100 μm, but is not limited thereto. For example, each of the different ceramic particles is about 1 nm to about 100 μm, about 10 nm to about 100 μm, about 50 nm to about 100 μm, about 100 nm to about 100 μm, about 500 nm to about 100 μm , About 1 nm to about 50 μm, about 1 nm to about 10 μm, about 1 nm to about 1 μm, about 1 nm to about 100 nm or about 1 nm to about 10 nm, but is not limited thereto. It is not.

According to the exemplary embodiment of the present invention, the particle size ratio between the different ceramic particles may be adjusted in a range of about 1: greater than about 1 to about 1: about 100,000 or less based on the smallest particle, but is not limited thereto. no. For example, the particle size ratio between the different ceramic particles may range from about 1: greater than about 1 to about 1: about 100,000 or less, about 1: greater than about 1 to about 1: about 10,000 or less, about 1, based on the smallest particle. : About 1 to about 1: about 1,000 or less, about 1: about 1 to about 1: about 800 or less, about 1: about 1 to about 1: about 600 or less, about 1: about 1 to about 1: About 400 or less, about 1: greater than about 1 to about 1: about 200 or less, about 1: greater than about 1 to about 1: about 100 or less, about 1: greater than about 1 to about 1: about 80 or less, about 1: about Greater than 1 to about 1: about 60 or less, about 1: about 1 or more to about 1: about 40 or less, about 1: about 10 or more to about 1: about 100,000 or less, about 1: about 10 or more to about 1: about 10,000 About 1: about 10 or more to about 1: about 1,000 or less, about 1: about 10 or more to about 1: about 800 or less, about 1: about 10 or more to about 1: about 600 or less, about 1: about 10 or more To About 1: about 400 or less, about 1: about 10 or more to about 1: about 200 or less, about 1: about 10 or more to about 1: about 100 or less, about 1: about 10 or more to about 1: about 80 or less, about 1: about 10 or more to about 1: about 60 or less, or about 1: about 10 or more to about 1: about 40 or less, but is not limited thereto.

The ceramic composite material according to the embodiment of the present application may be adjusted so as to prevent incomplete sintering during the sintering process by adjusting the content (volume) of each of the different ceramic particles used in the formation thereof in an appropriate range, but is not limited thereto. no. When the content of some ceramic particles in the sintering process is excessively high, incomplete sintering may occur, and the effect of improving the mechanical, electrical and / or thermal properties of the composite material may be reduced. Therefore, it is necessary to properly control the content range and ratio of each of the different ceramic particles. In one embodiment of the present disclosure, the content of each of the different ceramic particles is about 0 volume of each volume of the different ceramic particles based on the total volume of the mixture of different ceramic particles mixed before sintering during the manufacture of the ceramic composite material. It may be adjusted in the range of more than% to about 50% by volume, but is not limited thereto. For example, the volume of each of the different ceramic particles is greater than about 0% to about 50% by volume, and greater than about 0% by volume, based on the total volume of the mixture of different ceramic particles mixed before sintering in the manufacture of the ceramic composite material. To about 45 volume percent, greater than about 0 volume percent to about 40 volume percent, greater than about 0 volume percent to about 35 volume percent, greater than about 0 volume percent to about 30 volume percent, greater than about 0 volume percent to about 25 volume percent, Greater than about 0 volume% to about 20 volume%, greater than about 0 volume% to about 15 volume%, greater than about 0 volume% to about 10 volume%, about 5 volume% to about 50 volume%, about 5 volume% to about 45 Volume%, about 5 volume% to about 40 volume%, about 5 volume% to about 35 volume%, about 5 volume% to about 30 volume%, about 5 volume% to about 25 volume%, about 5 volume% to about 20 Volume%, about 5 volume% to about 15 volume%, about 5 volume% to about 10 volume%, about 10 volume% to about 50 volume%, about 10 parts % To about 45 vol%, about 10 vol% to about 40 vol%, about 10 vol% to about 35 vol%, about 10 vol% to about 30 vol%, about 10 vol% to about 25 vol%, about 10 vol % To about 20% by volume, or about 10% to about 15% by volume, but is not limited thereto.

According to one embodiment of the present application, the different ceramic particles may include two or three kinds of ceramic particles containing different components from each other, but is not limited thereto.

According to one embodiment of the present application, the different ceramic particles may include alumina particles and aluminum nitride particles, but are not limited thereto.

According to the exemplary embodiment of the present disclosure, the different ceramic particles may further include ceramic particles containing different ceramic components in addition to the alumina particles and the aluminum nitride particles, but are not limited thereto.

1 is a schematic view showing the structure of a ceramic composite material according to one embodiment of the present application. Referring to FIG. 1, a ceramic composite material according to an embodiment of the present disclosure is formed by uniformly dispersing different ceramic particles containing different ceramic components and having different particle sizes, for example, having a larger size. The particles may be uniformly dispersed among other particles having a smaller size, but are not limited thereto. In the ceramic composite material according to one embodiment of the present application of this type, the larger particles may be, for example, aluminum nitride particles, and the smaller particles may be, for example, alumina particles. Can be. Thus, by the size difference between the larger particles and the smaller particles, the sinterability of the mixed powder including the larger particles and the smaller particles is improved, thereby increasing the larger size. While improving the dispersibility of the particles, it is possible to minimize or avoid secondary phases in which the larger particles can be produced by reacting with the smaller particles. For example, by using alumina particles having a particle size smaller than that of the aluminum nitride particles, the sinterability of the alumina powder may be improved, and at the same time, the secondary phase that aluminum nitride reacts with the alumina may be minimized or avoided.

In one embodiment of the present application, when the amount of aluminum nitride dispersed between the alumina particles becomes excessive beyond the content range of each of the ceramic particles described above, for example, nitriding by the mutual sintering of aluminum nitride Aluminum and alumina may not be sintered. If aluminum nitride and alumina are not sintered in a portion of the composite powder, it is believed to slow the role of improving the mechanical, electrical or thermal properties of the composite material. Therefore, the amount of aluminum nitride dispersed in the alumina needs to be appropriately controlled.

According to an embodiment of the present disclosure, the alumina particles may have a size of several nm to several tens of micrometers or less, for example, about 1 nm to about 10 μm, about 10 nm to about 10 μm, about 50 nm to about 10 μm, about 100 nm to about 10 μm, about 500 nm to about 10 μm, about 1 nm to about 5 μm, about 1 nm to about 1 μm, about 1 nm to about 100 nm or about 1 nm to about 10 nm It may have a size of, but is not limited thereto.

In addition, various types of aluminum nitride in the aluminum nitride powder state may be applied. The aluminum nitride particles may have a size of several nm to several tens of micrometers or less, for example, each of the different ceramic particles may be from about 1 nm to about 100 μm, from about 10 nm to about 100 μm, from about 50 nm to about 100 μm, about 100 nm to about 100 μm, about 500 nm to about 100 μm, about 1 nm to about 50 μm, about 1 nm to about 10 μm, about 1 nm to about 1 μm, about 1 nm to about 100 nm Or it may have a size of about 1 nm to about 10 nm, but is not limited thereto.

Further, in order to minimize or avoid secondary phases formed by the reaction of the aluminum nitride with the alumina, the particle size ratio of the aluminum nitride and the alumina is about 1: greater than about 1 based on the aluminum nitride particles or the particles of the alumina. To about 1: about 100,000 or less, about 1: about 1 or more to about 1: about 10,000 or less, about 1: about 1 or more to about 1: about 1,000 or less, about 1: about 1 or more to about 1: about 800 or less, About 1: greater than about 1 to about 1: about 600 or less, about 1: greater than about 1 to about 1: about 400 or less, about 1: greater than about 1 to about 1: about 200 or less, about 1: greater than about 1 1: about 100 or less, about 1: about 1 or more to about 1: about 80 or less, about 1: about 1 or more to about 1: about 60 or less, about 1: about 1 or more to about 1: about 40 or less, about 1 From about 10 or more to about 1: about 100,000 or less, about 1: about 10 or more to about 1: about 10,000 or less, about 1: About 10 or more to about 1: about 1,000 or less, about 1: about 10 or more to about 1: about 800 or less, about 1: about 10 or more to about 1: about 600 or less, about 1: about 10 or more to about 1: about 400 or less, about 1: about 10 or more to about 1: about 200 or less, about 1: about 10 or more to about 1: about 100 or less, about 1: about 10 or more to about 1: about 80 or less, about 1: about 10 Or more to about 1: about 60 or less, or about 1: about 10 or more to about 1: about 40 or less, but is not limited thereto. That is, the aluminum nitride particles may be adjusted to have a size larger than the alumina particles or the aluminum nitride particles may have a size smaller than the alumina particles within the particle size ratio range, but is not limited thereto.

A second aspect of the present application provides a method of making the ceramic composite material according to the first aspect of the present application, comprising:

(a) adjusting the particle size of each of the different ceramic particles containing different ceramic components;

(b) dispersing and mixing the particle size controlled ceramics in a solvent to form a slurry;

(c) removing the solvent from the slurry to form a ceramic composite powder; And

(d) sintering the ceramic composite powder to form a ceramic composite material.

In one embodiment of the present invention, the ceramic composite material, the secondary particle formation between the different ceramic particles is reduced by sintering by controlling the particle size of the different ceramic particles differently from each other in a specific ratio range or There may be no secondary phase formation, but is not limited thereto.

2 is a flowchart illustrating a method of manufacturing a ceramic composite material according to one embodiment of the present application.

Method of manufacturing a ceramic composite material according to an embodiment of the present invention is the step of adjusting the particle size of each of the different ceramic particles containing different ceramic components (S100), the particle size controlled ceramics are dispersed and mixed in a solvent Forming a slurry (S110), removing the solvent from the slurry to form a ceramic composite powder (S120), and sintering the ceramic composite powder to form a ceramic composite material (S130). have.

According to one embodiment of the present disclosure, each of the different ceramic particles may have a particle size of about 1 nm to about 100 μm, but is not limited thereto. For example, each of the different ceramic particles is about 1 nm to about 100 μm, about 10 nm to about 100 μm, about 50 nm to about 100 μm, about 100 nm to about 100 μm, about 500 nm to about 100 μm , About 1 nm to about 50 μm, about 1 nm to about 10 μm, about 1 nm to about 1 μm, about 1 nm to about 100 nm, or about 1 nm to about 10 nm, but is not limited thereto. It doesn't happen.

The size of each of the different ceramic particles can be adjusted by the person skilled in the art using appropriate choices known in the art. For example, each of the different ceramic particle powders may be ball milled and sieved to obtain particles of a desired size, but are not limited thereto.

According to the exemplary embodiment of the present invention, the particle size ratio between the different ceramic particles may be adjusted in a range of about 1: greater than about 1 to about 1: about 100,000 or less based on the smallest particle, but is not limited thereto. no. For example, the particle size ratio between the different ceramic particles may range from about 1: greater than about 1 to about 1: about 100,000 or less, about 1: greater than about 1 to about 1: about 10,000 or less, about 1, based on the smallest particle. : About 1 to about 1: about 1,000 or less, about 1: about 1 to about 1: about 800 or less, about 1: about 1 to about 1: about 600 or less, about 1: about 1 to about 1: 400 or less, about 1: greater than about 1 to about 1: about 200 or less, about 1: greater than about 1 to about 1: about 100 or less, about 1: greater than about 1 to about 1: about 80 or less, about 1: about 1 Greater than about 1: about 60 or less, about 1: about 1 or more to about 1: about 40 or less, about 1: about 10 or more to about 1: about 100,000 or less, about 1: about 10 or more to about 1: about 10,000 or less About 1: about 10 or more to about 1: about 1,000 or less, about 1: about 10 or more to about 1: about 800 or less, about 1: about 10 or more to about 1: about 600 or less, about 1: about 10 or more1: about 400 or less, about 1: about 10 or more to about 1: about 200 or less, about 1: about 10 or more to about 1: about 100 or less, about 1: about 10 or more to about 1: about 80 or less, about 1 : About 10 or more to about 1: about 60 or less, or about 1: about 10 or more to about 1: about 40 or less, but is not limited thereto.

In one embodiment of the present application, by adjusting the sintering temperature range appropriately with the particle size control may be formed to reduce the secondary phase (secondary phase) formation or no secondary phase formation between the different ceramic particles, It is not limited to this.

In one embodiment, the sintering in step (d) is any one of a ceramic component having a maximum volume fraction among the different ceramic particles, a ceramic component having a minimum or maximum particle size, or a ceramic component having a lowest melting point. It may be performed at a temperature of about 60% to about 90% of the melting point of the component, but is not limited thereto. For example, the sintering in step (d) may comprise about 60% to about 90%, about 60% to about 80%, or about 60% to about 60% of the melting point of the ceramic component having the largest volume fraction of the different ceramic particles. It may be performed at a temperature of 70%, but is not limited thereto.

In another embodiment, the sintering in step (d) is carried out at a temperature of about 60% to about 90% of the melting point of the ceramic component having the smallest particle size or the ceramic component having the largest particle size among the different ceramic particles. It may be, but is not limited thereto. For example, sintering in step (d) may comprise from about 60% to about 90%, from about 60% to about 80, of the melting point of the ceramic component having the smallest or largest particle size among the different ceramic particles. %, Or about 60% to about 70%, but is not limited thereto.

In another embodiment, the sintering in step (d) may be performed at a temperature of about 60% to about 90% of the melting point of the ceramic component having the lowest melting point among the different ceramic particles, but is not limited thereto. no. For example, the sintering in step (d) may comprise about 60% to about 90%, about 60% to about 80%, or about 60% to about 70 of the melting point of the ceramic component having the lowest melting point of the different ceramic particles. It may be performed at a temperature of%, but is not limited thereto.

By adjusting the sintering temperature in the above conditions and ranges, the secondary phase formation between the different ceramic particles can be reduced or there can be no secondary phase formation.

In the ceramic composite material according to the embodiment of the present application, the different ceramic particles may be uniformly dispersed with each other, to improve the sinterability by the particle size difference between the different ceramic particles and the different ceramic particles By minimizing or avoiding the formation of secondary phases that may be formed in the liver, the sinterability, thermal properties, electrical properties, etc. of the ceramic composite material may be improved.

In one embodiment of the present application, step (c) may be to further include drying the ceramic composite powder, but is not limited thereto. The drying is not particularly limited so long as it is a temperature range capable of sufficiently removing the solvent, for example, may be about 70 ℃ to about 100 ℃, but is not limited thereto.

According to one embodiment of the present application, each of the ceramic particles may include a ceramic component selected from the group consisting of oxides, carbides, nitrides, borides, and combinations thereof, but is not limited thereto. When the ceramic components are mixed with each other and sintered without controlling the particle size differently as in the prior art, a secondary phase is formed between the different ceramic particles, thereby having limited electrical / thermal properties.

The nitride may include, for example, one or more selected from the group consisting of TiN, ZrN, HfN, VN, NbN, TaN, and combinations thereof, but is not limited thereto.

For example, the oxide may include one or more selected from the group consisting of SiO ₂ , TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , MgO, BeO, and combinations thereof, but is not limited thereto.

The carbide may include, for example, at least one selected from the group consisting of SiC, TiC, ZrC, HfC, VC, NbC, TaC, Mo ₂ C, or WC and combinations thereof, but is not limited thereto. It is not.

The boride may include, for example, one or more selected from the group consisting of TiB ₂ , ZrB ₂ , HfB ₂ , VB ₂ , NbB ₂ , TaB ₂ , WB ₂ , MoB _2, and combinations thereof. However, the present invention is not limited thereto.

The ceramic composite material according to one embodiment of the present application may prevent incomplete sintering during the sintering process by adjusting the content (volume or weight) of each of the different ceramic particles used in the formation thereof in an appropriate range. When the content of some ceramic particles in the sintering process is excessively high, when the incomplete sintering occurs, the effect of improving the mechanical, electrical and / or thermal properties of the composite material may be reduced. Therefore, it is necessary to properly control the content range and ratio of each of the different ceramic particles. In one embodiment of the present disclosure, the content of each of the different ceramic particles is about 0 volume of each volume of the different ceramic particles based on the total volume of the mixture of different ceramic particles mixed before sintering during the manufacture of the ceramic composite material. It may be adjusted in the range of more than% to about 50% by volume, but is not limited thereto. For example, the volume of each of the different ceramic particles is greater than about 0% to about 50% by volume, and greater than about 0% by volume, based on the total volume of the mixture of different ceramic particles mixed before sintering in the manufacture of the ceramic composite material. To about 45 volume percent, greater than about 0 volume percent to about 40 volume percent, greater than about 0 volume percent to about 35 volume percent, greater than about 0 volume percent to about 30 volume percent, greater than about 0 volume percent to about 25 volume percent, About 0% to about 20% by volume, about 0% to about 15% by volume, about 0% to about 10% by volume, about 5% to about 50% by volume, about 5% to about 45% by volume %, About 5% to about 40%, about 5% to about 35%, about 5% to about 30%, about 5% to about 25%, about 5% to about 20% %, About 5% to about 15%, about 5% to about 10%, about 10% to about 50%, about 10% by volume About 45% by volume, 10% by volume to about 40% by volume, 10% by volume to about 35% by volume, about 10% by volume to about 30% by volume, about 10% by volume to about 25% by volume, about 10% by volume to about 20% by volume, or about 10% by volume to about 15% by volume, but is not limited thereto.

According to one embodiment of the present application, the different ceramic particles may include two or three kinds of ceramic particles containing different components from each other, but is not limited thereto.

According to one embodiment of the present application, the different ceramic particles may include alumina particles and aluminum nitride particles, but are not limited thereto.

According to the exemplary embodiment of the present disclosure, the different ceramic particles may further include ceramic particles containing different ceramic components in addition to the alumina particles and aluminum nitride particles, but are not limited thereto.

According to one embodiment of the present application, the solvent may be used without particular limitation as long as it is a solvent capable of uniformly dispersing different ceramic particles, for example, the solvent may include water, alcohols, or other organic solvents. However, it is not limited thereto. In step (b), sonication may be used if necessary to further promote dispersion.

The sintering may include pressing and molding the ceramic composite powder into a pellet or the like in a metal mold having an empty space therein, and sintering plasma (spark plasma sintering = SPS). May be, but is not limited thereto. The temperature during the plasma sintering is at a temperature of about 60% to about 90% of the melting point of the ceramic component having the largest volume fraction of the different ceramic particles, or the ceramic component or the maximum particle size having the minimum particle size among the different ceramic particles. About 60% to about 90% of the melting point of the ceramic component having a temperature, or about 60% to about 90% of the melting point of the ceramic component having the lowest melting point among the different ceramic particles, but It is not limited. The sintering may be performed by applying pressure to the ceramic composite powder or pellets filled in the mold during the sintering, but is not limited thereto.

Hereinafter, the present invention will be described in more detail with reference to examples, but any form may be applied as long as it corresponds to the technical concept of the present application, and thus is not limited by the present embodiment.

[ Example ]

< Example 1 >

About 3 g of alumina powder having a size of about 2 μm to about 5 μm is placed in a polypropylene barrel containing zirconia balls, slurried by adding ethanol, and then milled by wet milling for about 48 hours, and maintained at about 90 ° C. Dried in a dry dryer to obtain alumina particles having a size of about 0.5 μm to about 1.0 μm.

The aluminum nitride plate was evenly ground in a mortar and sieved to obtain about 3 g of aluminum nitride particles having a size of about 40 μm to about 70 μm. Thereafter, in order to evenly mix the two powders, the pulverized alumina particles and the pulverized aluminum nitride particles were put in a polypropylene container containing zirconia balls, and ultrasonic waves were prepared by adding ethanol to produce a slurry, and the wet ball was about 1 hour. Milling was performed. Subsequently, the slurry after the wet ball milling was dried in a dryer maintained at about 90 ° C., thereby preparing a ceramic composite powder in which the aluminum nitride particles and the aluminum oxide particles were mixed at about 1: 1, respectively.

Then, the SPS sintering process was used to manufacture a ceramic composite material using the ceramic composite powder. To proceed with the sintering, a carbon mold of about 13 pi diameter was prepared and a BN spray was applied inside the carbon mold to prevent the carbon of the mold from diffusing into the material at high temperatures. Pressing the ceramic composite powder to produce pellets, the pellets were placed in the carbon mold and heated in a vacuum atmosphere at a rate of about 100 ° C. per minute to about 1400 ° C., followed by 0 and 5 minutes at about 1,400 ° C., respectively. Sintering was carried out by maintaining the temperature for 10 minutes. The pressure applied to the carbon mold during SPS sintering was about 50 MPa. After the sintering was completed, the sample was separated from the carbon mold after cooling by natural cooling in vacuum. Finally, the carbon diffusion layer on the surface of the ceramic composite material prepared using sandpaper was removed to prepare a finished ceramic composite material.

3 is a scanning electron microscope of each ceramic composite material including (a) aluminum nitride powder, (b) alumina powder, and (c) uniformly dispersed aluminum nitride particles and alumina particles according to an embodiment of the present disclosure. Electron Microscope = SEM). As shown in FIG. 3A, aluminum nitride has grains of several μm formed on the surface thereof. As shown in FIG. 3B, it was observed that the alumina powder was about 2 μm to about 5 μm in size. As shown in FIG. 3C, in the ceramic composite material, aluminum nitride particles of about 40 μm to about 70 μm and alumina particles of about 0.5 μm to about 1.0 μm were observed, with aluminum nitride being about 50% by volume.

The aluminum nitride is uniformly dispersed among the alumina particles. The aluminum nitride is dispersed in the alumina, and the secondary phase formation may be minimized due to the difference in the size of the aluminum nitride and the alumina matrix, and the thermal and electrical properties of the ceramic composite material may be improved. As shown in FIG. 3C, the ceramic composite material according to the present embodiment includes 50% by volume aluminum nitride.

Figure 4 is a schematic diagram showing a change in the phase (phase) appearing as the sintering process in the method of manufacturing a ceramic composite material according to an embodiment of the present application.

In the case of alumina, stable sintering occurs at about 1,400 ° C. to about 1,600 ° C., and sintering is also performed at about 1,700 ° C. as high. In contrast, aluminum nitride has a sintering temperature of about 1,700 ° C to about 2,000 ° C. In materials with a large difference in sintering temperature, the larger the aluminum nitride is produced, the slower the sintering will proceed at low sintering temperatures near the alumina sintering temperature. As shown in FIG. 4, when the material is designed to have a diameter difference of about 100 times the initial powder, and then sintering, necking occurs initially only in alumina, and only grain growth between aluminas occurs. Particle growth progresses to a slight extent and material diffusion occurs weakly with aluminum nitride to form a bond between the interfaces to form a composite material.

As shown in FIG. 4, in the first step, there are small sized alumina particles surrounding the large sized aluminum nitride particles. In the second stage, as the sintering begins, adjacent small alumina particles form a necking, indicating a phase change of the initial stage followed by a dumbbell shape. In the third stage, the phase change of the intermediate stage in which the production of alumina grown to the micrometer size by elemental diffusion and grain growth and the diffusion layer occurring between the aluminum nitride particles and the alumina is started. In the final step, the fourth step, the sintering process is completed, whereby the alumina crystal grains are fully grown, indicating the completion of the phase change of the microcomposite forming step including the diffusion layer formed at the interface between aluminum nitride and alumina.

5 is an XRD spectrum of the ceramic composite material according to the present embodiment. As shown in FIG. 5, in the XRD spectra of samples sintered at sintering temperatures of 1,400 ° C., 1,500 ° C., and 1,600 ° C., the blue rhombus is corundum and the pink triangle is aluminum oxynitride (Al _3). O ₃ N) and the red circle represent alumina nitride (AlN). In samples sintered at 1,400 ° C., little oxynitride was observed, suggesting that the production of diffusion layers was suppressed. The diffusion layer means a secondary phase.

Figure 6 is a graph showing the EDX analysis using STEM photographs and TEM for secondary phase analysis during the manufacture of a ceramic composite material according to an embodiment of the present application. As shown in FIG. 6, it can be seen that diffusion occurred differently according to the sintering temperature and time conditions at the interface between aluminum nitride and alumina, which is consistent with the result of FIG. 5. These results can be regarded as the biggest cause of the difference in sintering driving force by the size of the fine powder before sintering. As the size of the sintered fine powder decreases, the surface area per volume of the particles increases, thereby increasing the thermodynamic instability of the particles present on the surface. As a result, the surface energy of the alumina particles having a ratio of 100 times the size of the sintered fine powder increases, so that the sintering driving force between the alumina particles is much higher than the driving force between the alumina particles and the aluminum nitride particles or the aluminum nitride particles. The generation of is almost limited. The secondary phase accounts for only about 0.2% by volume of the total volume, which occurs to a very small extent.

7 is a graph showing the thermal conductivity and the electrical conductivity of the ceramic composite material according to an embodiment of the present application. As shown in Figure 7, it can be seen that the difference between the thermal conductivity and the resistance according to the temperature and time during sintering.

First, the composite material sintered at 1400 ℃ can be seen that the thermal conductivity value is improved as the sintering time increases. It is believed that as the sintering of the composite material increases the sintering time, the densification is performed and the thermal conductivity is improved by removing the pores. For another reason, as the sintering time increases, grain growth of alumina proceeds as shown in FIG. 4, and as the grain grows, the effect of dispersing phonons due to grains may be reduced. In addition, it was confirmed that 1,400 ° C. is the temperature at which the production of aluminum oxynitride is most limited as the material diffusion between aluminum nitride and alumina, as shown in the crystal analysis by XRD of FIG. 5. Since the production of aluminum oxynitride is limited, there is little effect of reducing the thermal conductivity by the secondary phase, it is possible to predict a desired physical property value before producing the composite material and actually produce a material similar to that. On the other hand, at 1,500 ° C, increasing the sintering holding time decreased the thermal conductivity value. As the sintering time increases, densification proceeds as the alumina grows, but as the sintering retention time increases, the diffusion of materials at the interface between aluminum nitride and alumina seems to decrease rapidly, reducing the thermal conductivity. At 1,400 ° C, the diffusion of the material appears to depend on the sintering temperature rather than the sintering time, and from 1,500 ° C and above it can be expected to be determined at the sintering temperature rather than the sintering time. Moreover, the highest thermal conductivity value of the ceramic composite material manufactured by the present Example showed 68.56 W / m * K. This is comparable to 71 W / m · K, the result predicted using the Rayleigh model, which means that the composite is produced in an ideal form with little solid solution.

As shown in FIG. 7, the electrical resistance of the ceramic composite material produced by the present embodiment was found to have better physical properties than 10 ¹⁴ Pa · cm. At 1,400 ℃, it was almost 10 ¹⁶ Ω · cm and the lowest electrical resistance was close to 10 ¹⁴ Ω · cm.

In summary, in the ceramic composite material according to the present embodiment, the aluminum nitride is uniformly dispersed between the alumina particles. When the sintering process is performed during the manufacturing process of the composite material, the aluminum nitride is dispersed in the alumina particles and the size of the alumina matrix particles is very small compared to the aluminum nitride particles, and thus the secondary phase is formed. It can minimize and improve the thermal and electrical properties of the ceramic composite material.

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics of the present invention. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention .

Claims (13)

A ceramic composite material comprising a sintered body, in which different ceramic particles containing different ceramic components and having different particle sizes are uniformly dispersed,
The particle size ratio between the different ceramic particles is adjusted in the range of greater than 1:50 to less than or equal to 1: 1,000, thereby reducing secondary phase formation or no secondary phase formation between the different ceramic particles, thereby improving sinterability, Thermal and electrical properties are to be improved, the ceramic composite material.
delete The method of claim 1,
Wherein each of the ceramic particles comprises a ceramic component selected from the group consisting of oxides, carbides, nitrides, borides, and combinations thereof.
The method of claim 1,
Wherein each of the different ceramic particles has a particle size of 1 nm to 100 μm.
delete The method of claim 1,
Wherein the different ceramic particles comprise two or three kinds of ceramic particles containing different components.
The method of claim 1,
Wherein the different ceramic particles comprise alumina particles and aluminum nitride particles.
The method of claim 7, wherein
Wherein the different ceramic particles further comprise ceramic particles containing different ceramic components in addition to the alumina particles and aluminum nitride particles.
(a) adjusting the ratio of the particle size of each of the different ceramic particles containing different ceramic components to a range of greater than 1:50 and less than or equal to 1: 1,000;
(b) dispersing and mixing the particle size controlled ceramics in a solvent to form a slurry;
(c) removing the solvent from the slurry to form a ceramic composite powder; And
(d) sintering the ceramic composite powder to form a ceramic composite material having reduced or no secondary phase formation between the different ceramic particles, thereby improving sinterability, thermal characteristics, and electrical characteristics.
Including, the manufacturing method of the ceramic composite material.
The method of claim 9,
The step (c) further comprises the step of drying the ceramic composite powder at a temperature of 70 ℃ to 100 ℃, ceramic composite material manufacturing method.
The method of claim 9,
Sintering in step (d) is 60% of the melting point of either the ceramic component having the largest volume fraction among the different ceramic particles, the ceramic component having the smallest or largest particle size, or the ceramic component having the lowest melting point. It is carried out at a temperature of 90% to 90%.
The method of claim 9,
Wherein in step (a) each of the different ceramic particles is adjusted to have a particle size of 1 nm to 100 μm.
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