High-thermal-conductivity aluminum oxide ceramic substrate and preparation method thereof

Abstract

The invention relates to the technical field of ceramic substrates, in particular to a high-heat-conductivity aluminum oxide ceramic substrate and a preparation method thereof.The high-heat-conductivity aluminum oxide ceramic substrate comprises aluminum oxide, beryllium oxide and silicon carbide which are all powdery, and the substrate further comprises a heat conduction preparation, a dispersing agent and a solvent, the weight parts of the aluminum oxide, the beryllium oxide, the silicon carbide, the heat conduction preparation, the dispersing agent and the solvent are respectively 59%-85%, 10%-16%, 8%-13%, 9%-15%, 7%-14% and 3%-8%, the heat conduction preparation is a mixture of diamond powder and graphene, and the proportions of the diamond powder and the graphene in the heat conduction preparation are 80%-90% and 18%-21%; the heat conduction performance of the ceramic substrate can be remarkably improved, the heat conduction efficiency of the ceramic substrate is enhanced, and meanwhile the ceramic substrate has good mechanical performance and machinability and adapts to various complex working environments.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic substrates, and in particular to a high thermal conductivity alumina ceramic substrate and a preparation method thereof. Background Art

[0002] Alumina ceramic substrate is a substrate made of ceramic material with alumina ceramic as the main body. It has excellent characteristics such as high mechanical strength, low dielectric constant, low dielectric loss, high thermal conductivity, excellent heat resistance and good chemical stability. Its core component uses a special process to directly bond copper foil to the surface of the alumina ceramic substrate at high temperature. It is widely used in high-power power semiconductor templates, power control circuits, automotive electronics, aerospace and military electronic components. With the vigorous development of the communications industry and the consumer electronics industry, the market demand for alumina ceramic substrates continues to grow. However, the existing alumina ceramic substrates have poor thermal conductivity and heat conduction efficiency, which can easily cause heat accumulation problems, leading to overheating of equipment, performance degradation or even damage, and there are certain disadvantages in the use process.

[0003] In view of this, the present invention is proposed. Summary of the invention

[0004] In order to overcome the technical defects of the prior art, the present invention provides a high thermal conductivity alumina ceramic substrate and a preparation method thereof, which can significantly improve the thermal conductivity of the ceramic substrate and enhance the thermal conduction efficiency of the ceramic substrate. At the same time, it can make the ceramic substrate have good mechanical properties and processability and adapt to a variety of complex working environments.

[0005] The technical solution adopted by the present invention is: the components include aluminum oxide, beryllium oxide and silicon carbide, and the aluminum oxide, beryllium oxide and silicon carbide are all in powder form. The substrate components also include a thermal conductive agent, a dispersant and a solvent. The aluminum oxide, the beryllium oxide, the silicon carbide, the thermal conductive agent, the dispersant and the solvent are 59%-85%, 10%-16%, 8%-13%, 9%-15%, 7%-14% and 3%-8% by weight respectively. The thermal conductive agent is a mixture of diamond powder and graphene, and the diamond powder and the graphene account for 80%-90% and 18%-21% of the thermal conductive agent.

[0006] Preferably, in order to achieve excellent heat dissipation performance of the substrate through a combination of high thermal conductivity aluminum oxide, beryllium oxide and silicon carbide, as well as suitable substrate thickness and density, and to be suitable for high-frequency, high-power electronic devices, the particle sizes of the aluminum oxide, beryllium oxide and silicon carbide are all between 200nm-500nm, the purity of the aluminum oxide and the beryllium oxide is greater than 99.9%, the thickness of the substrate is between 0.16mm-1.4mm, and the density of the substrate is greater than 4.2g / cm³.

[0007] Preferably, in order to promote uniform mixing of various components and form a protective layer on the surface of the particles, the particles' decontamination ability can be improved to prevent impurities from affecting the overall thermal conductivity of the ceramic substrate, the dispersant is a mixture of sodium stearate and sodium alkyl sulfonate, and the solvent is dibutyl phthalate.

[0008] Preferably, a method for preparing a high thermal conductivity alumina ceramic substrate comprises the following steps: Step S1: crushing the aluminum oxide, the beryllium oxide and the silicon carbide, and sieving the aluminum oxide and the beryllium oxide to form powders with a particle size of 200nm-500nm; Step S2: uniformly mixing the aluminum oxide, the beryllium oxide, the silicon carbide, the thermal conductive agent, the dispersant and the solvent, and obtaining a green ceramic substrate by a tape casting method; Step S3: placing the green ceramic substrate into a heating furnace for heating and binder removal treatment; Step S4: Sintering the green ceramic substrate to combine particles in the green ceramic substrate at high temperature to form a dense and hard ceramic body.

[0009] Preferably, in order to remove organic additives in the green ceramic substrate and avoid adverse effects on the performance of the final product, the green ceramic substrate is treated by a drying and curing process before the heating and debinding treatment to remove the solvent and volatile components therein.

[0010] Preferably, in order to avoid cracking of the green ceramic substrate, the heating and debinding treatment in step S3 is performed under normal pressure.

[0011] Preferably, in order to improve the density, strength and hardness of the ceramic substrate, and at the same time improve the electrical, thermal and mechanical properties of the ceramic substrate, the sintering temperature of the sintering process in step S4 is 1700°C, and the heating rate is 8°C / min from room temperature to 1200°C, and then 5°C / min after 1200°C to the sintering temperature.

[0012] Preferably, in order to ensure the uniformity and stability of the sintering process, when the sintering process of step S4 reaches the sintering temperature, it is kept warm for 5 hours; after the insulation is completed, it is cooled to below 1200°C at a rate of 5°C / min before 1200°C, and then cooled with the furnace.

[0013] The beneficial effects of the present invention are as follows: the thermal conductivity of the ceramic substrate is significantly improved by carefully proportioning aluminum oxide, beryllium oxide, and silicon carbide powders in combination with a mixed thermal conductive preparation of diamond powder and graphene. The high thermal conductivity of diamond powder and the excellent mechanical properties and thermal conductivity of graphene complement each other, and together enhance the thermal conduction efficiency of the ceramic substrate. At the same time, the ceramic substrate can have good mechanical properties and processability, and can adapt to a variety of complex working environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the composition of the ceramic substrate of the present invention.

[0015] Figure 2 Schematic diagram of the composition ratio of the ceramic substrate of the present invention.

[0016] Figure 3 It is a schematic diagram of the preparation process of the ceramic substrate of the present invention.

[0017] Figure 4 It is a schematic diagram of the sintering process of the green ceramic substrate of the present invention.

[0018] Figure 5 It is a schematic diagram of the process flow of debinding treatment of green ceramic substrates according to the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings: Embodiment 1 like Figure 1-Figure 5 As shown, this embodiment provides a high thermal conductivity alumina ceramic substrate and a preparation method thereof, wherein the components include alumina, beryllium oxide and silicon carbide, wherein the alumina, beryllium oxide and silicon carbide are all in powder form, and the substrate components also include a thermal conductive agent, a dispersant and a solvent, wherein the weight proportions of alumina, beryllium oxide, silicon carbide, the thermal conductive agent, the dispersant and the solvent are 59%, 10%, 8%, 9%, 7% and 3% respectively, and the thermal conductive agent is a mixture of diamond powder and graphene, and the proportions of diamond powder and graphene in the thermal conductive agent are 85% and 20% respectively.

[0020] The particle sizes of aluminum oxide, beryllium oxide and silicon carbide are all between 200nm and 500nm, the purity of aluminum oxide and beryllium oxide is greater than 99.9%, the thickness of the substrate is between 0.16mm and 1.4mm, the density of the substrate is greater than 4.2g / cm³, the dispersant is a mixture of sodium stearate and sodium alkyl sulfonate, and the solvent is dibutyl phthalate.

[0021] When preparing the high thermal conductivity alumina ceramic substrate, alumina, beryllium oxide and silicon carbide are crushed, and alumina and beryllium oxide are sieved to form powders with a particle size of 200nm-500nm; alumina, beryllium oxide, silicon carbide, thermal conductive agent, dispersant and solvent are mixed evenly, and a green ceramic substrate is obtained by a tape casting method; the green ceramic substrate is placed in a heating furnace for heating and debinding treatment; finally, the green ceramic substrate is sintered to combine the particles in the green ceramic substrate at high temperature to form a dense and hard ceramic body.

[0022] The green ceramic substrate is treated by drying and curing before the heating and debinding treatment to remove the solvent and volatile components therein. The heating and debinding treatment in step S3 is carried out under normal pressure. The sintering temperature of the sintering process in step S4 is 1700°C, and the heating rate is 8°C / min between room temperature and 1200°C, and after 1200°C, it is heated to the sintering temperature at 5°C / min. When the sintering temperature is reached, it is kept warm for 5 hours; after the insulation is completed, it is cooled to below 1200°C at a rate of 5°C / min before 1200°C, and then cooled with the furnace. The thermal conductivity of the ceramic substrate after cooling and forming is 182W / m·K at room temperature, which has high thermal conductivity.

[0023] Embodiment 2 like Figure 1-Figure 5 As shown, this embodiment provides a high thermal conductivity alumina ceramic substrate and a preparation method thereof, wherein the components include alumina, beryllium oxide and silicon carbide, wherein the alumina, beryllium oxide and silicon carbide are all in powder form, and the substrate components also include a thermal conductive agent, a dispersant and a solvent, wherein the weight proportions of alumina, beryllium oxide, silicon carbide, the thermal conductive agent, the dispersant and the solvent are 62%, 11%, 9%, 11%, 9% and 4% respectively, and the thermal conductive agent is a mixture of diamond powder and graphene, and the proportions of diamond powder and graphene in the thermal conductive agent are 85% and 20% respectively.

[0024] The particle sizes of aluminum oxide, beryllium oxide and silicon carbide are all between 200nm and 500nm, the purity of aluminum oxide and beryllium oxide is greater than 99.9%, the thickness of the substrate is between 0.16mm and 1.4mm, the density of the substrate is greater than 4.2g / cm³, the dispersant is a mixture of sodium stearate and sodium alkyl sulfonate, and the solvent is dibutyl phthalate.

[0025] When preparing the high thermal conductivity alumina ceramic substrate, alumina, beryllium oxide and silicon carbide are crushed, and alumina and beryllium oxide are sieved to form powders with a particle size of 200nm-500nm; alumina, beryllium oxide, silicon carbide, thermal conductive agent, dispersant and solvent are mixed evenly, and a green ceramic substrate is obtained by a tape casting method; the green ceramic substrate is placed in a heating furnace for heating and debinding treatment; finally, the green ceramic substrate is sintered to combine the particles in the green ceramic substrate at high temperature to form a dense and hard ceramic body.

[0026] The green ceramic substrate is treated by drying and curing before heating and debinding treatment to remove the solvent and volatile components therein. The heating and debinding treatment in step S3 is carried out under normal pressure. The sintering temperature of the sintering process in step S4 is 1700°C, and the heating rate is 8°C / min between room temperature and 1200°C, and after 1200°C, it is heated to the sintering temperature at 5°C / min. When the sintering temperature is reached, it is kept warm for 5 hours; after the insulation is completed, it is cooled to below 1200°C at a rate of 5°C / min before 1200°C, and then cooled with the furnace. The thermal conductivity of the ceramic substrate after cooling and forming is 178W / m·K at room temperature, which has high thermal conductivity.

[0027] Embodiment 3 like Figure 1-Figure 5 As shown, this embodiment provides a high thermal conductivity alumina ceramic substrate and a preparation method thereof, wherein the components include alumina, beryllium oxide and silicon carbide, wherein the alumina, beryllium oxide and silicon carbide are all in powder form, and the substrate components also include a thermal conductive agent, a dispersant and a solvent, wherein the weight proportions of alumina, beryllium oxide, silicon carbide, the thermal conductive agent, the dispersant and the solvent are 71%, 13%, 10%, 10%, 8% and 8% respectively, and the thermal conductive agent is a mixture of diamond powder and graphene, and the proportions of diamond powder and graphene in the thermal conductive agent are 85% and 20% respectively.

[0028] The particle sizes of aluminum oxide, beryllium oxide and silicon carbide are all between 200nm and 500nm, the purity of aluminum oxide and beryllium oxide is greater than 99.9%, the thickness of the substrate is between 0.16mm and 1.4mm, the density of the substrate is greater than 4.2g / cm³, the dispersant is a mixture of sodium stearate and sodium alkyl sulfonate, and the solvent is dibutyl phthalate.

[0029] When preparing the high thermal conductivity alumina ceramic substrate, alumina, beryllium oxide and silicon carbide are crushed, and alumina and beryllium oxide are sieved to form powders with a particle size of 200nm-500nm; alumina, beryllium oxide, silicon carbide, thermal conductive agent, dispersant and solvent are mixed evenly, and a green ceramic substrate is obtained by a tape casting method; the green ceramic substrate is placed in a heating furnace for heating and debinding treatment; finally, the green ceramic substrate is sintered to combine the particles in the green ceramic substrate at high temperature to form a dense and hard ceramic body.

[0030] The green ceramic substrate is treated by drying and curing before heating and debinding treatment to remove the solvent and volatile components therein. The heating and debinding treatment in step S3 is carried out under normal pressure. The sintering temperature of the sintering process in step S4 is 1700°C, and the heating rate is 8°C / min between room temperature and 1200°C, and after 1200°C, it is heated to the sintering temperature at 5°C / min. When the sintering temperature is reached, it is kept warm for 5 hours; after the insulation is completed, it is cooled to below 1200°C at a rate of 5°C / min before 1200°C, and then cooled with the furnace. The thermal conductivity of the ceramic substrate after cooling and forming is 190W / m·K at room temperature, which has high thermal conductivity.

[0031] Embodiment 4 like Figure 1-Figure 5 As shown, this embodiment provides a high thermal conductivity alumina ceramic substrate and a preparation method thereof, wherein the components include alumina, beryllium oxide and silicon carbide, wherein the alumina, beryllium oxide and silicon carbide are all in powder form, and the substrate components also include a thermal conductive agent, a dispersant and a solvent, wherein the weight proportions of alumina, beryllium oxide, silicon carbide, the thermal conductive agent, the dispersant and the solvent are 75%, 12%, 12%, 12%, 9% and 5% respectively, and the thermal conductive agent is a mixture of diamond powder and graphene, and the proportions of diamond powder and graphene in the thermal conductive agent are 85% and 20% respectively.

[0032] The particle sizes of aluminum oxide, beryllium oxide and silicon carbide are all between 200nm and 500nm, the purity of aluminum oxide and beryllium oxide is greater than 99.9%, the thickness of the substrate is between 0.16mm and 1.4mm, the density of the substrate is greater than 4.2g / cm³, the dispersant is a mixture of sodium stearate and sodium alkyl sulfonate, and the solvent is dibutyl phthalate.

[0033] When preparing the high thermal conductivity alumina ceramic substrate, alumina, beryllium oxide and silicon carbide are crushed, and alumina and beryllium oxide are sieved to form powders with a particle size of 200nm-500nm; alumina, beryllium oxide, silicon carbide, thermal conductive agent, dispersant and solvent are mixed evenly, and a green ceramic substrate is obtained by a tape casting method; the green ceramic substrate is placed in a heating furnace for heating and debinding treatment; finally, the green ceramic substrate is sintered to combine the particles in the green ceramic substrate at high temperature to form a dense and hard ceramic body.

[0034] The green ceramic substrate is treated by drying and curing before heating and debinding treatment to remove the solvent and volatile components therein. The heating and debinding treatment in step S3 is carried out under normal pressure. The sintering temperature of the sintering process in step S4 is 1700°C, and the heating rate is 8°C / min between room temperature and 1200°C, and after 1200°C, it is heated to the sintering temperature at 5°C / min. When the sintering temperature is reached, it is kept warm for 5 hours; after the insulation is completed, it is cooled to below 1200°C at a rate of 5°C / min before 1200°C, and then cooled with the furnace. The thermal conductivity of the ceramic substrate after cooling and forming is 186W / m·K at room temperature, which has high thermal conductivity.

[0035] Embodiment 5 like Figure 1-Figure 5 As shown, this embodiment provides a high thermal conductivity alumina ceramic substrate and a preparation method thereof, the components including alumina, beryllium oxide and silicon carbide, the alumina, beryllium oxide and silicon carbide are all in powder form, the substrate components also include a thermal conductive agent, a dispersant and a solvent, the weight proportions of alumina, beryllium oxide, silicon carbide, the thermal conductive agent, the dispersant and the solvent are 78%, 14%, 11%, 13%, 9% and 6% respectively, the thermal conductive agent is a mixture of diamond powder and graphene, and the proportions of diamond powder and graphene in the thermal conductive agent are 85% and 20% respectively.

[0036] The particle sizes of aluminum oxide, beryllium oxide and silicon carbide are all between 200nm and 500nm, the purity of aluminum oxide and beryllium oxide is greater than 99.9%, the thickness of the substrate is between 0.16mm and 1.4mm, the density of the substrate is greater than 4.2g / cm³, the dispersant is a mixture of sodium stearate and sodium alkyl sulfonate, and the solvent is dibutyl phthalate.

[0037] When preparing the high thermal conductivity alumina ceramic substrate, alumina, beryllium oxide and silicon carbide are crushed, and alumina and beryllium oxide are sieved to form powders with a particle size of 200nm-500nm; alumina, beryllium oxide, silicon carbide, thermal conductive agent, dispersant and solvent are mixed evenly, and a green ceramic substrate is obtained by a tape casting method; the green ceramic substrate is placed in a heating furnace for heating and debinding treatment; finally, the green ceramic substrate is sintered to combine the particles in the green ceramic substrate at high temperature to form a dense and hard ceramic body.

[0038] The green ceramic substrate is treated by drying and curing before heating and debinding treatment to remove the solvent and volatile components therein. The heating and debinding treatment in step S3 is carried out under normal pressure. The sintering temperature of the sintering process in step S4 is 1700°C, and the heating rate is 8°C / min between room temperature and 1200°C, and after 1200°C, it is heated to the sintering temperature at 5°C / min. When the sintering temperature is reached, it is kept warm for 5 hours; after the insulation is completed, it is cooled to below 1200°C at a rate of 5°C / min before 1200°C, and then cooled with the furnace. The thermal conductivity of the ceramic substrate after cooling and forming is 205W / m·K at room temperature, which has high thermal conductivity.

[0039] Embodiment 6 like Figure 1-Figure 5 As shown, this embodiment provides a high thermal conductivity alumina ceramic substrate and a preparation method thereof, the components including alumina, beryllium oxide and silicon carbide, the alumina, beryllium oxide and silicon carbide are all in powder form, the substrate components also include a thermal conductive agent, a dispersant and a solvent, the weight proportions of alumina, beryllium oxide, silicon carbide, the thermal conductive agent, the dispersant and the solvent are 85%, 16%, 13%, 15%, 14% and 8% respectively, the thermal conductive agent is a mixture of diamond powder and graphene, and the proportions of diamond powder and graphene in the thermal conductive agent are 85% and 20% respectively.

[0040] The particle sizes of aluminum oxide, beryllium oxide and silicon carbide are all between 200nm and 500nm, the purity of aluminum oxide and beryllium oxide is greater than 99.9%, the thickness of the substrate is between 0.16mm and 1.4mm, the density of the substrate is greater than 4.2g / cm³, the dispersant is a mixture of sodium stearate and sodium alkyl sulfonate, and the solvent is dibutyl phthalate.

[0041] When preparing the high thermal conductivity alumina ceramic substrate, alumina, beryllium oxide and silicon carbide are crushed, and alumina and beryllium oxide are sieved to form powders with a particle size of 200nm-500nm; alumina, beryllium oxide, silicon carbide, thermal conductive agent, dispersant and solvent are mixed evenly, and a green ceramic substrate is obtained by a tape casting method; the green ceramic substrate is placed in a heating furnace for heating and debinding treatment; finally, the green ceramic substrate is sintered to combine the particles in the green ceramic substrate at high temperature to form a dense and hard ceramic body.

[0042] The green ceramic substrate is treated by drying and curing before heating and debinding treatment to remove the solvent and volatile components therein. The heating and debinding treatment in step S3 is carried out under normal pressure. The sintering temperature of the sintering process in step S4 is 1700°C, and the heating rate is 8°C / min between room temperature and 1200°C, and after 1200°C, it is heated to the sintering temperature at 5°C / min. When the sintering temperature is reached, it is kept warm for 5 hours; after the insulation is completed, it is cooled to below 1200°C at a rate of 5°C / min before 1200°C, and then cooled with the furnace. The thermal conductivity of the ceramic substrate after cooling and forming is 212W / m·K at room temperature, which has high thermal conductivity.

[0043] Comparative Example 1 like Figure 1-Figure 5 As shown, this embodiment provides a high thermal conductivity alumina ceramic substrate and a preparation method thereof, the components including alumina, beryllium oxide and silicon carbide, the alumina, beryllium oxide and silicon carbide are all in powder form, the substrate components also include a thermal conductive agent, a dispersant and a solvent, the weight proportions of alumina, beryllium oxide, silicon carbide, the thermal conductive agent, the dispersant and the solvent are 54%, 9%, 6%, 7%, 5% and 2% respectively, the thermal conductive agent is a mixture of diamond powder and graphene, and the proportions of diamond powder and graphene in the thermal conductive agent are 85% and 20% respectively.

[0044] The particle sizes of aluminum oxide, beryllium oxide and silicon carbide are all between 200nm and 500nm, the purity of aluminum oxide and beryllium oxide is greater than 99.9%, the thickness of the substrate is between 0.16mm and 1.4mm, the density of the substrate is greater than 4.2g / cm³, the dispersant is a mixture of sodium stearate and sodium alkyl sulfonate, and the solvent is dibutyl phthalate.

[0045] When preparing the high thermal conductivity alumina ceramic substrate, alumina, beryllium oxide and silicon carbide are crushed, and alumina and beryllium oxide are sieved to form powders with a particle size of 200nm-500nm; alumina, beryllium oxide, silicon carbide, thermal conductive agent, dispersant and solvent are mixed evenly, and a green ceramic substrate is obtained by a tape casting method; the green ceramic substrate is placed in a heating furnace for heating and debinding treatment; finally, the green ceramic substrate is sintered to combine the particles in the green ceramic substrate at high temperature to form a dense and hard ceramic body.

[0046] The green ceramic substrate is treated by drying and curing before the heating and debinding treatment to remove the solvent and volatile components therein. The heating and debinding treatment in step S3 is carried out under normal pressure. The sintering temperature of the sintering process in step S4 is 1700°C, and the heating rate is 8°C / min between room temperature and 1200°C, and after 1200°C, it is heated to the sintering temperature at 5°C / min. When the sintering temperature is reached, it is kept warm for 5 hours; after the insulation is completed, it is cooled to below 1200°C at a rate of 5°C / min before 1200°C, and then cooled with the furnace. The thermal conductivity of the ceramic substrate after cooling and forming is 110W / m·K at room temperature, and the thermal conductivity is poor.

[0047] Comparative Example 2 like Figure 1-Figure 5 As shown, this embodiment provides a high thermal conductivity alumina ceramic substrate and a preparation method thereof, wherein the components include alumina, beryllium oxide and silicon carbide, wherein the alumina, beryllium oxide and silicon carbide are all in powder form, and the substrate components also include a thermal conductive agent, a dispersant and a solvent, wherein the weight proportions of alumina, beryllium oxide, silicon carbide, the thermal conductive agent, the dispersant and the solvent are 89%, 17%, 17%, 16%, 15% and 10% respectively, and the thermal conductive agent is a mixture of diamond powder and graphene, and the proportions of diamond powder and graphene in the thermal conductive agent are 85% and 20% respectively.

[0048] The particle sizes of aluminum oxide, beryllium oxide and silicon carbide are all between 200nm and 500nm, the purity of aluminum oxide and beryllium oxide is greater than 99.9%, the thickness of the substrate is between 0.16mm and 1.4mm, the density of the substrate is greater than 4.2g / cm³, the dispersant is a mixture of sodium stearate and sodium alkyl sulfonate, and the solvent is dibutyl phthalate.

[0049] When preparing the high thermal conductivity alumina ceramic substrate, alumina, beryllium oxide and silicon carbide are crushed, and alumina and beryllium oxide are sieved to form powders with a particle size of 200nm-500nm; alumina, beryllium oxide, silicon carbide, thermal conductive agent, dispersant and solvent are mixed evenly, and a green ceramic substrate is obtained by a tape casting method; the green ceramic substrate is placed in a heating furnace for heating and debinding treatment; finally, the green ceramic substrate is sintered to combine the particles in the green ceramic substrate at high temperature to form a dense and hard ceramic body.

[0050] The green ceramic substrate is treated by drying and curing before the heating and debinding treatment to remove the solvent and volatile components therein. The heating and debinding treatment in step S3 is carried out under normal pressure. The sintering temperature of the sintering process in step S4 is 1700°C, and the heating rate is 8°C / min between room temperature and 1200°C, and after 1200°C, it is heated to the sintering temperature at 5°C / min. When the sintering temperature is reached, it is kept warm for 5 hours; after the insulation is completed, it is cooled to below 1200°C at a rate of 5°C / min before 1200°C, and then cooled with the furnace. The thermal conductivity of the ceramic substrate after cooling and forming is 102W / m·K at room temperature, and the thermal conductivity is poor.

[0051] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A high thermal conductivity alumina ceramic substrate, comprising alumina, beryllium oxide and silicon carbide, characterized in that: The aluminum oxide, the beryllium oxide and the silicon carbide are all in powder form, and the substrate components also include a thermally conductive agent, a dispersant and a solvent. The aluminum oxide, the beryllium oxide, the silicon carbide, the thermally conductive agent, the dispersant and the solvent account for 59%-85%, 10%-16%, 8%-13%, 9%-15%, 7%-14% and 3%-8% by weight, respectively. The thermally conductive agent is a mixture of diamond powder and graphene, and the diamond powder and the graphene account for 80%-90% and 18%-21% of the thermally conductive agent.

2. The high thermal conductivity alumina ceramic substrate according to claim 1, characterized in that: The particle sizes of the aluminum oxide, the beryllium oxide and the silicon carbide are all between 200nm and 500nm, the purity of the aluminum oxide and the beryllium oxide is greater than 99.9%, the thickness of the substrate is between 0.16mm and 1.4mm, and the density of the substrate is greater than 4.2g / cm³.

3. The high thermal conductivity alumina ceramic substrate according to claim 1, characterized in that: The dispersant is a mixture of sodium stearate and sodium alkyl sulfonate, and the solvent is dibutyl phthalate.

4. A method for preparing a high thermal conductivity alumina ceramic substrate according to any one of claims 1 to 3, characterized in that: The steps include: Step S1: crushing the aluminum oxide, the beryllium oxide and the silicon carbide, and sieving the aluminum oxide and the beryllium oxide to form powders with a particle size of 200nm-500nm; Step S2: uniformly mixing the aluminum oxide, the beryllium oxide, the silicon carbide, the thermal conductive agent, the dispersant and the solvent, and obtaining a green ceramic substrate by a tape casting method; Step S3: placing the green ceramic substrate into a heating furnace for heating and binder removal treatment; Step S4: Sintering the green ceramic substrate to combine particles in the green ceramic substrate at high temperature to form a dense and hard ceramic body.

5. The high thermal conductivity alumina ceramic substrate and the preparation method thereof according to claim 4, characterized in that: The green ceramic substrate is treated by a drying and curing process before the heating and debinding process to remove the solvent and volatile components.

6. The high thermal conductivity alumina ceramic substrate and the preparation method thereof according to claim 4, characterized in that: The heating debinding process in step S3 is performed under normal pressure.

7. The high thermal conductivity alumina ceramic substrate and the preparation method thereof according to claim 4, characterized in that: The sintering temperature of the sintering process in step S4 is 1700° C., and the heating rate is 8° C. / min from room temperature to 1200° C., and 5° C. / min after 1200° C. to the sintering temperature.

8. The high thermal conductivity alumina ceramic substrate and the preparation method thereof according to claim 7, characterized in that: When the sintering process in step S4 reaches the sintering temperature, the temperature is kept at this temperature for 5 hours. After the temperature is kept at this temperature, the temperature is cooled to below 1200° C. at a rate of 5° C. / min before the temperature reaches 1200° C., and then the temperature is cooled along with the furnace.

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