阅读说明：本技术 一种氧化铝增强zta陶瓷基板及其制备方法 (Alumina-reinforced ZTA ceramic substrate and preparation method thereof ) 是由 包亦望 旷峰华 李海燕 万德田 于 2020-12-30 设计创作，主要内容包括：本发明公开一种氧化铝增强ZTA陶瓷基板及其制备方法,所述氧化铝增强ZTA陶瓷基板包括ZTA基体和包覆所述ZTA基体的氧化铝表层。本发明在基体表面进行压缩预应力设计,通过对材料组分、基体与表层膨胀系数的比值,基体和表层的厚度比值等关键参数的控制,经过高温同烧过程,实现了结构功能一体化设计,制备得到的氧化铝增强ZTA陶瓷基板具有高强度和高导热性。本发明提供的制备工艺简单、效果好,基体和表层的复合可采用大部分现有陶瓷成型工艺、烧结工艺,适用于工业大批量生产。(The invention discloses an alumina reinforced ZTA ceramic substrate and a preparation method thereof. According to the invention, the compressive prestress design is carried out on the surface of the matrix, the structural function integrated design is realized by controlling key parameters such as material components, the ratio of the expansion coefficients of the matrix and the surface layer, the thickness ratio of the matrix and the surface layer and the like, and the prepared alumina reinforced ZTA ceramic substrate has high strength and high thermal conductivity through a high-temperature co-firing process. The preparation process provided by the invention is simple and has good effect, and the composition of the matrix and the surface layer can adopt most of the existing ceramic forming process and sintering process, so that the preparation process is suitable for industrial mass production.)

1. An alumina-reinforced ZTA ceramic substrate, comprising a ZTA matrix and an alumina surface layer coating the ZTA matrix.

2. The alumina reinforced ZTA ceramic substrate of claim 1, wherein the alumina skin fully encapsulates the ZTA matrix;

or the surface layer of the aluminum oxide partially coats the ZTA matrix.

3. The alumina reinforced ZTA ceramic substrate of claim 1, wherein the ZTA matrix has a thickness of 0.1mm to 1.0mm, and the alumina surface layer has a thickness of 0.001mm to 0.05 mm.

4. The alumina reinforced ZTA ceramic substrate of claim 1, wherein the ratio of the thickness of the ZTA matrix to the thickness of the alumina skin is 20:1 to 500: 1.

5. A method of making the alumina-reinforced ZTA ceramic substrate of any one of claims 1-4, comprising the steps of:

preparing a ZTA matrix biscuit;

and preparing an alumina surface layer biscuit on the surface of the ZTA matrix biscuit, and sintering to obtain the alumina reinforced ZTA ceramic substrate.

6. The method of claim 5, wherein the ZTA matrix biscuit is prepared by a method comprising the steps of:

preparing a ZTA matrix blank by a molding process;

and drying the ZTA matrix blank, and then pre-burning and removing glue to obtain the ZTA matrix biscuit.

7. The method of claim 6, wherein the molding process is selected from one of a dry press molding process, a gel injection molding process, a slip casting process, and a tape casting process.

8. The preparation method of claim 6, wherein the temperature of the pre-sintering binder removal treatment is 600-1100 ℃, and the heat preservation time of the pre-sintering binder removal treatment is 30-120 min.

9. The method according to claim 5, wherein the step of preparing the alumina surface layer green body on the surface of the ZTA matrix green body and sintering the alumina surface layer green body to obtain the alumina-reinforced ZTA ceramic substrate comprises:

preparing alumina slurry;

covering the surface of the ZTA matrix biscuit with alumina slurry;

and sintering the ZTA matrix biscuit covered with the alumina slurry, and then cooling to obtain the alumina reinforced ZTA ceramic substrate.

10. The method according to claim 9, wherein the temperature of the sintering process is 1350 ℃ to 1800 ℃ and the holding time of the sintering process is 30min to 180 min.

Technical Field

The invention relates to the field of ceramics, in particular to an alumina reinforced ZTA ceramic substrate and a preparation method thereof.

Background

The ceramic substrate is widely applied to the electronic industry, and the ceramic substrate is required to have high heat conductivity, high strength, high thermal shock resistance and high thermal fatigue resistance. The existing single-phase oxide ceramics are difficult to meet the requirements. The Zirconia Toughened Alumina (ZTA) material is rarely used as a substrate, and although the strength is high, the heat-conducting property is difficult to meet the requirement.

Accordingly, the prior art is yet to be improved and developed.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present invention aims to provide an alumina-reinforced ZTA ceramic substrate and a method for preparing the same, which aims to solve the problem that the conventional ZTA ceramic has poor thermal conductivity and cannot be used as a ceramic substrate.

The technical scheme of the invention is as follows:

an alumina-reinforced ZTA ceramic substrate, wherein the alumina-reinforced ZTA ceramic substrate comprises a ZTA matrix and an alumina surface layer coating the ZTA matrix.

Optionally, the aluminum oxide surface layer fully coats the ZTA matrix;

or the surface layer of the aluminum oxide partially coats the ZTA matrix.

Optionally, the ZTA matrix has a thickness of 0.1mm to 1.0mm, and the alumina surface layer has a thickness of 0.001mm to 0.05 mm.

Optionally, the ratio of the thickness of the ZTA matrix to the thickness of the alumina surface layer is 20:1 to 500: 1.

The invention relates to a preparation method of an alumina reinforced ZTA ceramic substrate, which comprises the following steps:

preparing a ZTA matrix biscuit;

and preparing an alumina surface layer biscuit on the surface of the ZTA matrix biscuit, and sintering to obtain the alumina reinforced ZTA ceramic substrate.

Optionally, the method for preparing a ZTA matrix biscuit comprises the steps of:

preparing a ZTA matrix blank by a molding process;

and drying the ZTA matrix blank, and then pre-burning and removing glue to obtain the ZTA matrix biscuit.

Optionally, the molding process is selected from one of a dry press molding process, a gel injection molding process, a slip casting process, a tape casting process.

Optionally, the temperature of the pre-sintering glue discharging treatment is 600-1100 ℃, and the heat preservation time of the pre-sintering glue discharging treatment is 30-120 min.

Optionally, the step of preparing an alumina surface layer biscuit on the surface of the ZTA matrix biscuit, and performing sintering treatment to obtain the alumina reinforced ZTA ceramic substrate includes:

preparing alumina slurry;

covering the surface of a ZTA matrix biscuit with alumina slurry;

and sintering the ZTA matrix biscuit covered with the alumina slurry, and then cooling to obtain the alumina reinforced ZTA ceramic substrate.

Optionally, the temperature of the sintering treatment is 1350-1800 ℃, and the heat preservation time of the sintering treatment is 30-180 min.

Has the advantages that: the invention provides an alumina reinforced ZTA ceramic substrate and a preparation method thereof, which realize the integration improvement of structural function through the design of surface prestress, and the alumina reinforced ZTA ceramic substrate has high strength and high thermal conductivity at the same time. The preparation process provided by the invention is simple, has good effect and is suitable for industrial mass production.

Drawings

FIG. 1 is a schematic structural view of an alumina-reinforced ZTA ceramic substrate with an alumina surface layer fully coated with a ZTA matrix.

Fig. 2 is a schematic structural view of an alumina-reinforced ZTA ceramic substrate in which a ZTA matrix is partially coated on an alumina surface layer.

Detailed Description

The invention provides an alumina-reinforced ZTA ceramic substrate and a preparation method thereof, and the invention is further described in detail below in order to make the purpose, technical scheme and effect of the invention clearer and more clear. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The embodiment of the invention provides an alumina reinforced ZTA ceramic substrate, which comprises a ZTA matrix and an alumina surface layer coating the ZTA matrix.

The ceramic material is typically brittle, and the surface residual compressive stress can greatly improve the overall bending strength. The heat-conducting property of the alumina ceramic is higher than that of the ZTA ceramic, the expansion coefficient of the alumina ceramic is lower than that of the ZTA ceramic, the surface of a ZTA matrix biscuit is plated with an alumina surface layer biscuit, after high-temperature sintering, the shrinkage is different to form surface layer residual compressive stress, and the bending strength of the alumina reinforced ZTA ceramic substrate is greatly improved; meanwhile, the thermal conductivity of the surface alumina is better than that of the base material, so that the strength and the thermal conductivity of the alumina-reinforced ZTA ceramic substrate are improved at the same time, and the structural function integration is improved.

In one embodiment, the ZTA matrix has a volume fraction of zirconia of 5% to 45%.

Further, in one embodiment, the ZTA matrix has a volume fraction of zirconia of 10% to 25%.

In this example, the alumina surface layer is composed of alumina particles. In one embodiment, the alumina particles have a particle size of 0.15 μm to 3 μm.

In one embodiment, the alumina surface layer 2 completely coats the ZTA matrix 1, as shown in fig. 1.

The full coating in this embodiment means that the ZTA substrate is assumed to be plate-shaped, and has six surfaces, i.e., an upper surface, a lower surface, a left surface, a right surface, a front surface, and a rear surface, and the aluminum oxide surface layer is coated on all six surfaces of the ZTA substrate. The improvement of the heat conduction performance and other performances of the composite ceramic substrate can be better realized by adopting full cladding.

In one embodiment, the alumina surface layer 2 partially coats the ZTA matrix 1, as shown in fig. 2.

It should be noted that, in the present embodiment, the partial coating is assumed that the ZTA matrix is plate-shaped, and has six surfaces, which are an upper surface, a lower surface, a left surface, a right surface, a front surface, and a rear surface, and the aluminum oxide surface layer is partially coated on the upper surface, the lower surface, the front surface, and the rear surface of the ZTA matrix, and is not coated on the left surface and the right surface of the ZTA matrix. Of course, the aluminum oxide surface layer can also be partially coated on the upper surface and the lower surface of the ZTA matrix.

In one embodiment, the ZTA matrix has a thickness of 0.1mm to 1.0mm, and the alumina surface layer has a thickness of 0.001mm to 0.05 mm.

Theoretically, the smaller the ratio of the thickness of the aluminum oxide surface layer to the thickness of the ZTA matrix is, the better the obtained prestress effect is, but the too thin surface layer has the problems of higher defect sensitivity, reduced heat conduction effect and the like.

In one embodiment, the ratio of the thickness of the ZTA matrix to the thickness of the alumina surface layer is from 20:1 to 500: 1. Within this thickness ratio range, the alumina reinforced ZTA ceramic substrates have higher strength and thermal conductivity.

In this embodiment, the thickness of the ZTA substrate may be a vertical distance between the upper surface and the lower surface of the ZTA substrate, and the thickness of the corresponding alumina surface layer is a thickness of the surface layer coated on the upper surface or the lower surface of the ZTA substrate, where the thicknesses of the alumina surface layers on the upper surface or the lower surface of the ZTA substrate are equal.

In this embodiment, the thickness of the ZTA substrate may also be a vertical distance between the left surface and the right surface of the ZTA substrate, and the thickness of the corresponding aluminum oxide surface layer is a thickness of the surface layer coated on the left surface or the right surface of the ZTA substrate, where the thicknesses of the aluminum oxide surface layers on the left surface or the right surface of the ZTA substrate are equal.

In this embodiment, the thickness of the ZTA substrate may also be a vertical distance between the front surface and the rear surface of the ZTA substrate, and the thickness of the corresponding aluminum oxide surface layer is a thickness of the surface layer coated on the front surface or the rear surface of the ZTA substrate, where the thicknesses of the aluminum oxide surface layers on the front surface or the rear surface of the ZTA substrate are equal.

In the embodiment of the invention, the structural function is integrally improved by controlling key parameters such as the components of the base material and the surface layer material, the ratio of the expansion coefficient of the base body to the surface layer, the ratio of the thickness of the base body to the surface layer and the like, so that the strength and the heat-conducting property of the alumina reinforced ZTA ceramic substrate are improved simultaneously.

The embodiment of the invention also provides a preparation method of the alumina reinforced ZTA ceramic substrate, which comprises the following steps:

s1, preparing a ZTA matrix biscuit;

s2, preparing an alumina surface layer biscuit on the surface of the ZTA matrix biscuit, and sintering to obtain the alumina reinforced ZTA ceramic substrate.

In step S1, in one embodiment, the method for preparing a ZTA matrix biscuit comprises the steps of:

preparing a ZTA matrix blank by a molding process;

and drying the ZTA matrix blank, and then pre-burning and removing glue to obtain the ZTA matrix biscuit.

In one embodiment, the molding process is selected from one of a dry press molding process, a gel injection molding process, a slip casting process, a tape casting process, but is not limited thereto.

In one embodiment, the temperature of the pre-sintering and glue discharging treatment is 600-1100 ℃, and the biscuit of the ZTA matrix is ensured to be flat in the pre-sintering and glue discharging process at high temperature.

In one embodiment, the heat preservation time of the pre-sintering glue discharging treatment is 30min-120 min.

In one embodiment, the step of preparing an alumina surface layer green body on the surface of the ZTA base green body and sintering the alumina surface layer green body to obtain the alumina-reinforced ZTA ceramic substrate in step S2 includes:

preparing alumina slurry;

covering the surface of a ZTA matrix biscuit with alumina slurry;

and sintering the ZTA matrix biscuit covered with the alumina slurry, and then cooling to obtain the alumina reinforced ZTA ceramic substrate.

In one embodiment, the method for coating the surface of the ZTA matrix biscuit with the alumina slurry is selected from one of a dipping method, a spraying method and a brushing method, but is not limited thereto.

In one embodiment, the alumina slurry covers the ZTA matrix biscuit surface either completely or partially.

In one embodiment, the alumina slurry is fully coated on the surface of the ZTA matrix biscuit, so that the improvement of the performance of the alumina reinforced ZTA ceramic substrate is better realized.

In one embodiment, the temperature of the sintering treatment is 1350-1800 ℃, and the heat preservation time of the sintering treatment is 30-180 min.

In one embodiment, before sintering the ZTA substrate blank covered with the alumina slurry, the ZTA substrate covered with the alumina slurry is dried.

In the embodiment, the thermal conductivity coefficient of the alumina surface layer is higher than that of the ZTA matrix, the expansion coefficient of the alumina surface layer is lower than that of the ZTA matrix, the surface of the ZTA matrix is coated with the alumina surface layer, and the surface layer residual compressive stress is formed due to different shrinkage after high-temperature sintering, so that the bending strength of the alumina reinforced ZTA ceramic substrate is greatly improved; meanwhile, the thermal conductivity coefficient of the surface layer of the alumina is higher than that of the ZTA matrix, so that the strength and the thermal conductivity of the alumina reinforced ZTA ceramic substrate are improved at the same time, and the structural function integration is improved.

The invention is further illustrated by the following specific examples.

Example 1

The alumina-reinforced ZTA ceramic substrate of the present example was prepared as follows:

(1) preparing a ZTA matrix blank with the volume fraction of zirconia of 15% by a tape casting process, drying the ZTA matrix blank, then preserving the heat at the high temperature of 1100 ℃ for 120min to finish pre-sintering and binder removal, and ensuring the flatness to obtain a ZTA matrix biscuit.

(2) Weighing a certain mass of alumina powder, adding deionized water accounting for 20% of the mass of the alumina powder, 1% of ammonium polyacrylate dispersant, 0.1% of defoaming agent and 200% of ceramic grinding balls, and carrying out ball milling at the rotating speed of 100rpm for 24 hours, wherein the particle size of the selected alumina powder is 3 microns, so as to prepare the alumina slurry. And (2) uniformly and completely coating the alumina slurry on the surface of the ZTA matrix biscuit subjected to the step (1) by adopting a spraying method, wherein the ratio of the thickness of the alumina surface layer to the ZTA matrix biscuit is equal to 1: 20. And then the whole body is dried to obtain a composite ceramic substrate biscuit.

(3) And carrying out high-temperature co-firing on the composite ceramic substrate biscuit at the high temperature of 1800 ℃, keeping the temperature for 180min, and then carrying out synchronous cooling to prepare the alumina reinforced ZTA ceramic substrate.

The test results show that: under the same sintering condition, the bending strength of the ZTA matrix is 550MPa, the bending strength of the alumina surface layer is 375MPa, the bending strength of the prepared alumina reinforced ZTA ceramic substrate is 824MPa, the bending strength of the prepared alumina reinforced ZTA ceramic substrate is improved by about 119% relative to the bending strength of the alumina surface layer, and the bending strength of the ZTA matrix is improved by about 50% relative to the bending strength of the ZTA matrix.

The thermal conductivity coefficient of the ZTA matrix is 20W/mK, the thermal conductivity coefficient of the prepared alumina reinforced ZTA ceramic substrate is 30W/mK, and the thermal conductivity coefficient of the prepared alumina reinforced ZTA ceramic substrate is improved by 50 percent relative to the thermal conductivity coefficient of the ZTA matrix.

Example 2

The alumina-reinforced ZTA ceramic substrate of the present example was prepared as follows:

(1) preparing a ZTA matrix blank with the volume fraction of zirconium oxide of 25% by a tape casting process, drying the ZTA matrix blank, then preserving heat for 30min at the high temperature of 600 ℃ to finish pre-sintering and binder removal, and ensuring the flatness to obtain a ZTA matrix biscuit.

(2) Weighing a certain mass of alumina powder, adding deionized water accounting for 20% of the mass of the alumina powder, 1% of ammonium polyacrylate dispersant, 0.1% of defoaming agent and 200% of ceramic grinding balls, and carrying out ball milling at the rotating speed of 100rpm for 24 hours, wherein the particle size of the selected alumina powder is 0.15 mu m, thus obtaining the alumina slurry. And (2) uniformly and completely coating the alumina slurry on the surface of the ZTA matrix biscuit subjected to the step (1) by adopting a spraying method, wherein the ratio of the thickness of the alumina surface layer to the ZTA matrix biscuit is 1: 500. And then the whole body is dried to obtain a composite ceramic substrate biscuit.

(3) And carrying out high-temperature co-firing on the composite ceramic substrate biscuit at 1350 ℃ for 30min, and then carrying out synchronous cooling to prepare the alumina reinforced ZTA ceramic substrate.

The test results show that: under the same sintering condition, the bending strength of the ZTA matrix is 603MPa, the bending strength of the alumina surface layer is 482MPa, the bending strength of the prepared alumina reinforced ZTA ceramic substrate is 895MPa, the bending strength of the prepared alumina reinforced ZTA ceramic substrate is improved by about 85 percent relative to the bending strength of the alumina surface layer, and the bending strength of the ZTA ceramic substrate is improved by about 48 percent relative to the bending strength of the ZTA matrix.

The thermal conductivity coefficient of the ZTA matrix is 16W/mK, the thermal conductivity coefficient of the prepared alumina reinforced ZTA ceramic substrate is 27W/mK, and the thermal conductivity coefficient of the prepared alumina reinforced ZTA ceramic substrate is improved by 68 percent relative to the thermal conductivity coefficient of the ZTA matrix.

In summary, according to the alumina-reinforced ZTA ceramic substrate and the preparation method thereof provided by the invention, the compressive prestress design is performed on the surface of the substrate, the structural-function integrated design is realized through controlling key parameters such as the material components, the ratio of the expansion coefficients of the substrate and the surface layer, and the thickness ratio of the substrate and the surface layer, and through the high-temperature co-firing process, the prepared alumina-reinforced ZTA ceramic substrate has high strength and high thermal conductivity. The preparation process provided by the invention is simple and has good effect, and the composition of the matrix and the surface layer can adopt most of the existing ceramic forming process and sintering process, so that the preparation process is suitable for industrial mass production.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.