WO2022095597A1

WO2022095597A1 - Alumina composite ceramic, preparation method therefor, and application therefor

Info

Publication number: WO2022095597A1
Application number: PCT/CN2021/117498
Authority: WO
Inventors: 伍尚华; 张威; 郭伟明
Original assignee: 广东工业大学
Priority date: 2020-11-09
Filing date: 2021-09-09
Publication date: 2022-05-12
Also published as: CN112279628B; CN112279628A

Abstract

The present application pertains to the technical field of ceramic materials, and in particular relates to an alumina composite ceramic, a preparation method therefor, and an application thereof. The present application provides an alumina composite ceramic. The alumina composite ceramic is composed of composite particles and AlN particles. The composite particles are composed of Al ₂O ₃, Y ₂O ₃, and m-ZrO ₂. The AlN particles are attached to the surface of the composite particles. A three-dimensional network distribution of AlN is formed by molding in the alumina composite ceramic. By means of the above structure and composition, the alumina composite ceramic, the preparation method therefor, and the application thereof provided by the present application provides can effectively solve the technical problem of high sintering costs caused by low mechanical properties, low thermal conductivity, and high sintering temperatures of existing alumina ceramics.

Description

A kind of alumina composite ceramic and its preparation method and application

technical field

The application belongs to the technical field of ceramic materials, and in particular relates to an alumina composite ceramic and a preparation method and application thereof.

Background technique

With the development of science and technology, the printed circuit board (PCB) has become an indispensable electronic component. Since the 1990s, countries around the world have gradually renamed printed circuit boards as electronic substrates, marking that traditional printed circuit boards have entered the era of multi-layer substrates. Electronic circuits are increasingly dense and miniaturized, and thermal conductivity has become one of the bottlenecks hindering the further development of printed circuit boards.

In the prior art, the inorganic substrates are mostly made of Al ₂ O ₃ ceramic materials. Since the sintering temperature of pure alumina ceramics is above 1800°C, the sintering cost is relatively high; in order to reduce the sintering cost, a sintering aid is usually added to reduce the sintering However, the thermal conductivity of these sintering aids is relatively low, and at the same time, a thicker grain boundary phase is formed after sintering, which leads to the thermal conductivity of Al ₂ O ₃ ceramic substrates mostly in the range of 20-26W·m-1·K-1 ; In order to improve the thermal conductivity of the Al ₂ O ₃ ceramic substrate, in the sintering process, AlN particles are usually added as a high thermal conductivity phase, but the sintered AlN grains are wrapped by Al ₂ O ₃ grains, and the AlN particles are The role of AlN particles is limited, and it is often necessary to add a large amount (>30wt%) of AlN particles to improve the thermal conductivity of Al ₂ O ₃ ceramics. The sintering temperature of AlN particles is also above 1800 ° C. This kind of alumina ceramics with a large amount of AlN particles added It is difficult to sinter and densify below 1700 °C, resulting in a still high sintering cost of alumina ceramics. At the same time, the room temperature bending strength of alumina ceramics is between 300 and 450MPa, and the mechanical properties are not high.

SUMMARY OF THE INVENTION

In view of this, the present application provides an alumina composite ceramic and a preparation method and application thereof, which are used to solve the technical problems of high sintering cost caused by low mechanical properties, low thermal conductivity and high sintering temperature of alumina ceramics.

A first aspect of the present application provides an alumina composite ceramic, which is composed of composite particles and AlN particles;

The particle size of the composite particles is 50 μm-70 μm, and the particle size of the AlN particles is 0.5 μm;

The composite particles are composed of Al ₂ O ₃ , Y ₂ O ₃ and m-ZrO ₂ ;

The AlN particles are distributed on the surface of the composite particles.

Preferably, the AlN particles are distributed on the surface of the composite particles in a three-dimensional network structure.

Preferably, in parts by mass, each part of the alumina composite ceramic is composed of the following proportions;

Composite particles 85-95 copies;

AlN particles 5-15 parts.

Preferably, in parts by mass, the composite particles are composed of the following raw materials;

Al ₂ O ₃ 80.7-84.5 parts;

12.7-14.6 parts of m-ZrO ₂ ;

Y ₂ O ₃ 0.7-2.7 parts.

A second aspect of the present application provides a method for preparing an alumina composite ceramic, comprising the steps of:

Step 1, adding Al ₂ O ₃ , Y ₂ O ₃ and m-ZrO ₂ to a solvent, performing ball milling and mixing, and drying to obtain a first composite powder;

Step 2, spray granulating the first composite powder to obtain first composite particles;

Step 3. Dry ball milling the first composite particles and AlN particles to obtain second composite particles;

Step 4, molding the second composite particles to obtain an alumina ceramic body;

Step 5, sintering the alumina ceramic body at a high temperature under a protective atmosphere to obtain the alumina ceramic;

The particle size of the first composite particles is 50 μm-70 μm, and the particle size of the AlN particles is 0.5 μm.

Preferably, the solvent is one or more of ethanol, propanol, methanol or acetone.

Preferably, in step 1, the ball-milling mixing is performed on a roller ball mill for 1-48 hours, and the first composite powder is obtained after drying;

The ball-milling and mixing in step 3 is ball-milling and mixing on a planetary ball mill for 2 to 12 hours to obtain second composite particles.

Preferably, the heating rate of the high-temperature sintering is 5-10°C/min, the temperature of the high-temperature sintering is 1200-1700°C, the pressure of the high-temperature sintering is 0.1-1MPa, and the time of the high-temperature sintering is 1- 4h.

Preferably, the ball milling speed of the planetary ball mill is 250 r/min.

A third aspect of the present application provides the application of alumina composite ceramics as electronic component materials.

Compared with the prior art, the present application has the following beneficial effects:

1. In the present application, by mixing Al ₂ O ₃ with m-ZrO ₂ and Y ₂ O ₃ and then sintering at high temperature, when AlN and Al ₂ O ₃ are sintered, a small amount of Al ₆ O ₃ N ₄ and Al ₇ O ₃ will be formed N ₅ and Al ₈ O ₃ N ₆ as reinforcing phases can significantly improve the mechanical properties of alumina ceramics.

2. In the present application, the first composite particles are obtained by spray granulation of the first composite powder mixed with Al ₂ O ₃ , Y ₂ O ₃ and m-ZrO ₂ , and the first composite particles are obtained by dry ball milling of the first composite particles and AlN particles. The second composite particle, the particle size of the first composite particle is 50μm-70μm, the particle size of the AlN particle is 0.5μm, the particle size of the composite particle is much larger than that of the AlN particle, so adding a small amount of AlN particle can make the AlN particle distribution On the surface of the composite particles, the AlN particles are prevented from being wrapped by the composite particles, so that the AlN can fully exert its thermal conductivity; further, the present application also attaches the AlN particles to the surface of the second composite particles, and molds them on the alumina composite ceramics. The three-dimensional network structure distribution of AlN is formed in the composite, which reduces the scattering of heat in the ceramic, thereby further improving the thermal conductivity of the alumina composite ceramic.

3. In the present application, the first composite particles are obtained by spray granulation of the first composite powder after mixing Al ₂ O ₃ , Y ₂ O ₃ and m-ZrO ₂ , and the first composite particles are obtained by dry ball milling of the first composite particles and AlN particles. The second composite particle; the particle size of the first composite particle is 50 μm-70 μm, the particle size of the AlN particle is 0.5 μm, and the particle size of the composite particle is much larger than that of the AlN particle, which avoids the AlN particle being compounded when a small amount of AlN is added. Powder wrapping reduces the addition amount of aluminum nitride in the alumina composite ceramic, thereby reducing the sintering temperature and sintering cost of the alumina composite ceramic.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that are required to be used in the description of the embodiments or the prior art.

Fig. 1 is the sample crystal phase microscope photograph prepared by the embodiment of the application;

Fig. 2 is the SEM photo of the sample prepared by the embodiment of the application and the corresponding element distribution diagram;

FIG. 3 is a black-and-white comparison of the SEM photo and the corresponding element distribution diagram shown in FIG. 2 .

Detailed ways

The present application provides an alumina composite ceramic and a preparation method and application thereof, which are used to solve the problems of high sintering cost caused by low mechanical properties, low thermal conductivity and high sintering temperature of alumina ceramics.

The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

The particle size of Al ₂ O ₃ used in the following examples is 1 μm, the particle size of m-ZrO ₂ is 1 μm, the particle size of Y ₂ O ₃ is 2 μm, and the particle size of AlN is 0.5 μm. More than 99%.

Example 1

Embodiment 1 of the present application provides the first alumina composite ceramic, and its specific preparation method is as follows:

1. In parts by mass, mix 80.7 parts of Al ₂ O ₃ , 13.6 parts of m-ZrO ₂ , and 0.7 parts of Y ₂ O ₃ , use ethanol as a solvent, and use Al ₂ O ₃ as a ball milling medium, and mix on a roller ball mill 12h, the first composite powder is obtained after mixing and drying;

2. Put the first composite powder into a spray granulator, and spray granulation to obtain a first composite particle with a particle size of 50 μm;

3. In parts by mass, ball mill 95 parts of the first composite particles and 5 parts of AlN particles on a planetary ball mill at a rotational speed of 250 r/min for 12 hours to obtain the second composite particles;

4. Molding the second composite particles to obtain an alumina composite ceramic embryo;

5. Put the alumina composite ceramic body into the boron nitride crucible, then put the boron nitride crucible into the sintering furnace, fill the sintering furnace with _N2 as a protective gas, and under the sintering pressure of 0.1MPa, to After heating at a rate of 5°C/min to 1200°C for 4 hours, an alumina ceramic with a density of 98% was obtained.

Example 2

Embodiment 2 of the present application provides a second alumina composite ceramic, and its specific preparation method is as follows:

1. In parts by mass, mix 80.7 parts of Al ₂ O ₃ , 14.6 parts of m-ZrO 2 and 2.7 parts of Y ₂ O ₃ , use ethanol as a solvent, and use Al ₂ O ₃ as a ball milling medium, and mix on a roller ball mill for 24 hours , the first composite powder is obtained after mixing and drying;

3. In parts by mass, ball mill 92 parts of the first composite particles and 8 parts of AlN particles on a planetary ball mill at a rotational speed of 250 r/min for 8 hours to obtain a second composite powder;

5. Put the alumina composite ceramic body into the boron nitride crucible, then put the boron nitride crucible into the sintering furnace, fill the sintering furnace with _N2 as a protective gas, and under the sintering pressure of 0.1MPa, to After heating at a rate of 10°C/min to 1400°C for 2 hours, an alumina ceramic with a density of 98.2% was obtained.

Example 3

Embodiment 3 of the present application provides a third alumina composite ceramic, and its specific preparation method is as follows:

1. In parts by mass, mix 82.5 parts of Al ₂ O ₃ , 12.3 parts of m-ZrO 2 and 1.2 parts of Y ₂ O ₃ , use ethanol as the solvent, and use Al ₂ O ₃ as the ball milling medium, and mix on a roller ball mill for 48 hours , the first composite powder is obtained after mixing and drying;

2. Put the first composite powder into a spray granulator, and spray granulation to obtain a first composite particle with a particle size of 60 μm;

3. In parts by mass, ball mill 88 parts of the first composite particles and 12 parts of AlN particles on a planetary ball mill at a rotational speed of 250 r/min for 6 hours to obtain the second composite particles;

5. Put the alumina composite ceramic body into the boron nitride crucible, then put the boron nitride crucible into the sintering furnace, fill the sintering furnace with _N2 as a protective gas, and under the sintering pressure of 0.1MPa, to After heating at a rate of 10°C/min to 1600°C for 2 hours, an alumina ceramic with a density of 99% was obtained.

Example 4

Embodiment 4 of the present application provides the fourth alumina composite ceramic, and its specific preparation method is as follows:

1. In parts by mass, mix 82.5 parts of Al ₂ O ₃ , 14.4 parts of m-ZrO 2 and 2.1 parts of Y ₂ O ₃ , use ethanol as the solvent, and use Al ₂ O ₃ as the ball milling medium, and mix on a roller ball mill for 48 hours , the first composite powder is obtained after mixing and drying;

3. In parts by mass, ball mill 85 parts of the first composite particles and 15 parts of AlN particles on a planetary ball mill at a rotational speed of 250 r/min for 12 hours to obtain the second composite particles;

5. Put the alumina composite ceramic body into the boron nitride crucible, then put the boron nitride crucible into the sintering furnace, fill the sintering furnace with _N2 as a protective gas, and under the sintering pressure of 0.1MPa, to After heating at a rate of 10°C/min to 1700°C for 2 hours, an alumina ceramic with a density of 97.2% was obtained.

Comparative Example 1:

Comparative example 1 of the present application provides a kind of alumina ceramics, and its concrete preparation method is as follows:

1. Molding Al ₂ O ₃ particles to obtain an alumina ceramic body;

2. Put the alumina ceramic body into the boron nitride crucible, then put the boron nitride crucible into the sintering furnace, fill the sintering furnace with N ₂ as a protective gas, under the sintering pressure of 0.1MPa, with 10 After heating to 1800°C for 2 hours at a rate of ℃/min, alumina ceramics were obtained.

Comparative Example 2:

Comparative example 2 of the present application provides a kind of alumina composite ceramics, and its concrete preparation method is as follows:

1. In parts by mass, 82.5 parts of Al ₂ O ₃ , 14.4 parts of m-ZrO 2 and 3.1 parts of Y ₂ O ₃ were mixed on a roller ball mill for 24 hours using ethanol as a solvent and Al ₂ O ₃ as a ball milling medium. The composite powder is obtained after mixing and drying;

2. The composite powder body is molded to obtain the alumina composite ceramic body;

3. Put the alumina composite ceramic embryo into an alumina crucible, then put the alumina crucible into a muffle furnace, and heat up to 1800°C at a rate of 10°C/min for 2 hours to obtain alumina ceramics.

Real time example 5:

Example 5 of the present application is to conduct room temperature bending strength, fracture toughness and thermal conductivity tests on the alumina composite ceramics and alumina ceramics prepared in Examples 1-4 and Comparative Example 1.

1. Room temperature flexural strength test: use ASTM C 1684-2008 "Standard Test Method for Flexural Strength of Advanced Ceramics at Room Temperature" for testing;

2. Fracture toughness test: use ASTM C 1421-2009 "Fracture Toughness Test of Advanced Ceramics at Room Temperature" for testing;

3. Thermal conductivity test: ASTM D 5470-2012 "Standard Test Method for Heat Transfer Characteristics of Thermally Conductive Electrical Insulating Materials" is used for testing.

The test results are shown in Table 1:

Table 1

It can be understood from Examples 1-4 of the present application and Comparative Example 1 that, by adding a sintering aid and aluminum nitride to alumina, Al ₆ O ₃ N ₄ , Al ₇ O ₃ N ₅ , and Al ₈ O can be generated ₃ N ₆ is used as a reinforcing phase to improve the mechanical properties such as indoor bending strength and _fracture _toughness _of alumina _ceramics _; The composite particles are obtained by dry ball milling the composite particles and AlN particles to obtain the second composite particles, so that adding a small amount of AlN can make the AlN particles distribute on the surface of the composite particles, reducing the amount of AlN added in the alumina ceramics, and then The sintering temperature and sintering cost of alumina composite ceramics are reduced.

It can be understood from the above examples and accompanying drawings that in the present application, Al ₂ O ₃ , Y ₂ O ₃ and m-ZrO ₂ are mixed by ball milling and then spray granulated into composite particles with a particle size of 50 μm-70 μm, and then the The composite particles are ball _- milled with AlN with a particle size of 0.5 μm, so that the small AlN particles are distributed on the surface of the large composite particles. ₃ composite phases, so that AlN can exert its high thermal conductivity and improve the thermal conductivity of alumina composite ceramics; further, the present application also attaches AlN particles to the surface of the second composite particles, and forms a three-dimensional AlN in the material by molding The distribution of the network structure, as shown in the SEM photo and the corresponding element distribution diagram in Figure 2, shows that the Al, O, Zr elements are evenly distributed, while the N element distribution is approximately circular, which proves that AlN forms a three-dimensional network structure in the matrix. Since the heat scattering between AlN grains and AlN grains is much smaller than the heat scattering between AlN grains and Al ₂ O ₃ grains, Al ₂ O ₃ grains and Al ₂ O ₃ grains, The connected three-dimensional network AlN can reduce the heat scattering between Al ₂ O ₃ grains and Al ₂ O ₃ grains, and between Al ₂ O ₃ grains and AlN grains, thereby further improving the thermal conductivity of alumina composite ceramics .

The above are only the preferred embodiments of the present application. It should be pointed out that for those skilled in the art, without departing from the principles of the present application, several improvements and modifications can be made. It should be regarded as the protection scope of this application.

Claims

An alumina composite ceramic, characterized in that it is composed of composite particles and AlN particles;

The particle size of the composite particles is 50 μm-70 μm, and the particle size of the AlN particles is 0.5 μm;

The composite particles are composed of Al 2 O 3 , Y 2 O 3 and m-ZrO 2 ;

The AlN particles are distributed on the surface of the composite particles.
The alumina composite ceramic according to claim 1, wherein the AlN particles are distributed on the surface of the composite particles in a three-dimensional network structure.
The alumina composite ceramic according to claim 1, wherein, in parts by mass, each part of the alumina composite ceramic is composed of the following proportions;

85-95 copies of composite particles;

5-15 AlN particles;

In parts by mass, the composite particles are composed of the following raw materials;

Al 2 O 3 80.7-84.5 parts;

12.7-14.6 parts of m-ZrO 2 ;

Y 2 O 3 0.7-2.7 parts.
A preparation method of alumina composite ceramics, characterized in that, comprising the steps of:

Step 1. Add Al 2 O 3 , Y 2 O 3 and m-ZrO 2 into a solvent for ball milling and mixing, and obtain a first composite powder after drying. In parts by mass, the raw material ratios of Al 2 O 3 , Y 2 O 3 and m-ZrO 2 are respectively It is: Al2O3 is 80.7-84.5 parts; m-ZrO2 is 12.7-14.6 parts; Y2O3 is 0.7-2.7 parts;

Step 2, spray granulating the first composite powder to obtain first composite particles;

Step 3. Dry ball milling the first composite particles and AlN particles to obtain second composite particles;

Step 4, sintering the second composite particles at a high temperature under a protective atmosphere to obtain the alumina composite ceramic;

The particle size of the first composite particles is 50 μm-70 μm, and the particle size of the AlN particles is 0.5 μm.
A kind of preparation method of alumina composite ceramics according to claim 4, is characterized in that, after described step 3 specifically comprises:

The alumina composite ceramic body is obtained by molding the second composite particles, and the alumina composite ceramic body is sintered at a high temperature under a protective atmosphere to obtain the alumina composite ceramic body.
The method for preparing alumina composite ceramics according to claim 4 or 5, wherein the solvent is one or more of ethanol, propanol, methanol or acetone.
The preparation method of alumina composite ceramics according to claim 4 or 5, wherein,

In step 1, the ball-milling mixing is performed on a roller ball mill for 1-48 hours, and the first composite powder is obtained after drying;

The ball-milling and mixing in step 3 is ball-milling and mixing on a planetary ball mill for 2 to 12 hours to obtain second composite particles.
The preparation method of alumina composite ceramics according to claim 4 or 5, characterized in that, the heating rate of the high-temperature sintering is 5-10°C/min, the temperature of the high-temperature sintering is 1200-1700°C, and the The pressure of high temperature sintering is 0.1-1MPa, and the time of the high temperature sintering is 1-4h.
The method for preparing alumina composite ceramics according to claim 7, wherein the ball milling speed of the planetary ball mill is 250 r/min.
Application of the alumina composite ceramic according to any one of claims 1-3 or the preparation method of the alumina composite ceramic according to any one of claims 4-9 as an electronic component material.