Aluminum nitride ceramic heater plate body and preparation method thereof

Abstract

The invention provides an aluminum nitride ceramic heater plate body and a preparation method thereof, and the preparation method comprises the following steps: preparing aluminum nitride powder, an electrode piece and a heating piece, preparing a ceramic biscuit through dry pressing molding, and then sequentially carrying out hot isostatic pressing sintering, sheath removal and machining to obtain the aluminum nitride ceramic heater plate body. According to the preparation method, the compactness of the aluminum nitride ceramic can be effectively guaranteed, the compactness reaches 99.5-99.9%, the aluminum nitride material is uniform in grain, free of color difference in material appearance and uniform in density, the heat conductivity of the aluminum nitride ceramic can be guaranteed, the heat conductivity is larger than or equal to 150 W / mK, the bending strength is larger than or equal to 300 MPa, the use requirement is met, the operation steps can be simplified, and the cost is reduced. The production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor ceramics, specifically to aluminum nitride ceramics, and particularly to an aluminum nitride ceramic heater disk body and a preparation method thereof. Background Art

[0002] Aluminum nitride ceramics have excellent thermal conductivity, chemical stability, and insulation properties, and are applied to rapidly developing fields such as semiconductor components, high-power power semiconductors, intelligent power modules, automotive electronics, and solar energy. However, aluminum nitride ceramic materials are strong covalent bond compounds, and it is very difficult to perform densification sintering under normal pressure.

[0003] Existing solutions mostly use hot pressing sintering and pressureless sintering to achieve the sintering of aluminum nitride ceramics, which have limitations in terms of material uniformity and densification. The hot pressing sintering process is prone to causing non-uniform product density. Hot pressing sintering uses unidirectional pressure and heating simultaneously to achieve densification. The powder moves unidirectionally and fills during the sintering process. In this case, whether the powder loading in the mold is flat at the beginning will affect the uniformity of the part. Local non-uniformity will cause differences in thermal conductivity in some areas of the material, and even abnormal phenomena such as color difference, resulting in cracking during use under high-temperature conditions. Pressureless sintering mostly uses the steps of forming, debinding, and pressureless sintering to prepare aluminum nitride ceramics. Since pressureless sintering can only provide the only driving force of temperature, the densification process is more dependent on sintering aids to form a liquid phase to fill the pores. The internal pores cannot be effectively eliminated due to the limitations of sintering time and temperature during the sintering process, resulting in poor densification. Currently, many related works on improving the thermal conductivity and mechanical properties of aluminum nitride have been reported. For example, CN 112811909 A proposes a method for preparing high-strength and high-thermal-conductivity aluminum nitride by hot pressing sintering, using the method of pre-sintering - hot pressing sintering - high-temperature annealing, reducing the oxygen content by pre-sintering and annealing, and preparing ceramics with an average grain size of less than 3μm, a thermal conductivity higher than 200W / m·k, a total oxygen content lower than 1%, and a flexural strength higher than 350MPa. However, the sintering steps are complex, the energy consumption cost is high, and it is not suitable for large-scale production.

[0004] In contrast, hot isostatic pressing sintering can effectively achieve uniform material preparation at each position, while ensuring the densification and thermal conductivity of aluminum nitride ceramics. Hot isostatic pressing sintering is to apply the same pressure in all directions while heating the powder green body to be sintered, so that the powder is densified at a temperature lower than the conventional sintering temperature. Compared with tape casting + pressureless sintering, hot isostatic pressing sintering can better improve the density of the material, reduce the sintering temperature, reduce the amount of sintering aids used, thereby improving the product performance, and obtaining aluminum nitride ceramic materials with high density, excellent thermal conductivity and strength. For example, CN 116589293 A discloses a preparation method of nickel-doped enhanced aluminum nitride ceramics. The preparation method includes uniformly mixing to prepare ceramic slurry, drying, dry pressing, cold isostatic pressing, and sintering in sequence, and then performing post-treatment of hot isostatic pressing on the sintered aluminum nitride ceramics, which can further improve its flexural strength, so as to obtain nickel-doped enhanced aluminum nitride ceramics. However, this technical solution has complex steps and high energy consumption costs, and is not suitable for large-scale production.

[0005] In summary, there is a need to provide a new preparation method for the heater plate body of aluminum nitride ceramics, which can not only effectively ensure the densification of aluminum nitride ceramics, ensure the thermal conductivity of aluminum nitride ceramics, but also simplify the operation steps and reduce the production cost. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a heater plate body of aluminum nitride ceramics and a preparation method thereof. The preparation method includes: preparing aluminum nitride powder, electrode parts, and heating parts, and obtaining a ceramic green body by dry pressing, and then successively performing hot isostatic pressing sintering, removing the jacket, and machining to obtain the heater plate body of aluminum nitride ceramics. The preparation method of the present invention can not only effectively ensure the densification of aluminum nitride ceramics, with the densification rate reaching 99.5-99.9%, the grains of the aluminum nitride material are uniform, the appearance of the material has no color difference, and the density is uniform, can ensure the thermal conductivity of aluminum nitride ceramics, the thermal conductivity ≥ 150 W / mK, can ensure the flexural strength ≥ 300 MPa, meeting the use requirements, but also simplify the operation steps and reduce the production cost.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] One of the purposes of the present invention is to provide a preparation method for the heater plate body of aluminum nitride ceramics, and the preparation method includes the following steps:

[0009] (1) Prepare aluminum nitride powder, electrode parts, and heating parts, and obtain a ceramic green body by dry pressing;

[0010] (2) Put the ceramic green body obtained in step (1) into a jacket and seal it, and successively perform hot isostatic pressing sintering, remove the jacket, and machine to obtain the heater plate body of aluminum nitride ceramics.

[0011] In the preparation method of the present invention, pure aluminum nitride powder without adding sintering aids is used. First, a ceramic green body is obtained by dry pressing, and then hot isostatic pressing sintering is carried out, so that the aluminum nitride powder is subjected to isotropic pressure, can fully flow and deform, and the pores can be eliminated, realizing good densification of the aluminum nitride ceramic. The preparation method of the present invention can avoid the situation of uneven material density and poor densification in hot pressing sintering and pressureless sintering, and obtain an aluminum nitride disk body with good performance. It can not only effectively ensure the densification of the aluminum nitride ceramic, with the density reaching 99.5-99.9%, the grains of the aluminum nitride material are uniform, the appearance of the material has no color difference, and the density is uniform, but also ensure the thermal conductivity of the aluminum nitride ceramic, with the thermal conductivity ≥ 150W / mK, and ensure the flexural strength ≥ 300MPa, meeting the use requirements. It can also simplify the operation steps and reduce the production cost.

[0012] As a preferred technical solution of the present invention, in step (1), the purity of the aluminum nitride powder is 99.0-99.9wt%, such as 99.0wt%, 99.1wt%, 99.3wt%, 99.5wt%, 99.7wt% or 99.9wt%, etc.

[0013] Preferably, in step (1), the particle size of the aluminum nitride powder is 0.8-1.2μm, such as 0.8μm, 0.9μm, 1.0μm, 1.1μm or 1.2μm, etc.

[0014] Preferably, in step (1), the electrode member includes a molybdenum mesh.

[0015] Preferably, in step (1), the heating member includes a molybdenum heating wire or a molybdenum heating sheet.

[0016] As a preferred technical solution of the present invention, in step (1), the dry pressing includes the following steps:

[0017] Prepare a mold, fill the aluminum nitride powder to the bottom of the mold to form a first aluminum nitride layer, place an electrode member above the first aluminum nitride layer, fill aluminum nitride powder above the electrode member and form a second aluminum nitride layer, and perform the first dry pressing;

[0018] Place a heating member above the formed body obtained by the first dry pressing, fill aluminum nitride powder above the heating member and form a third aluminum nitride layer, and perform the second dry pressing to obtain the ceramic green body.

[0019] As a preferred technical solution of the present invention, the pressing pressure of the first dry pressing is 20-40MPa, such as 20MPa, 25MPa, 30MPa, 35MPa or 40MPa, etc.

[0020] Preferably, the pressure holding time for the first dry pressing and forming is 10 to 20 minutes, such as 10 minutes, 11 minutes, 13 minutes, 15 minutes, 16 minutes, 18 minutes or 20 minutes, etc.

[0021] Preferably, the pressing pressure for the second dry pressing and forming is 40 to 50 Mpa, such as 40 Mpa, 41 Mpa, 43 Mpa, 45 Mpa, 46 Mpa, 48 Mpa or 50 Mpa, etc.

[0022] Preferably, the pressure holding time for the second dry pressing and forming is 10 to 20 minutes, such as 10 minutes, 11 minutes, 13 minutes, 15 minutes, 16 minutes, 18 minutes or 20 minutes, etc.

[0023] As a preferred technical solution of the present invention, in step (2), the jacket is a glass jacket with a softening temperature of 1200 to 1600 °C as the hot isostatic pressing jacket for aluminum nitride ceramics, and argon is used as the protective gas.

[0024] In the present invention, the softening temperature of the glass jacket is 1200 to 1600 °C, such as 1200 °C, 1250 °C, 1300 °C, 1350 °C, 1400 °C, 1450 °C, 1500 °C, 1550 °C or 1600 °C, etc.

[0025] As a preferred technical solution of the present invention, in step (2), the hot isostatic pressing sintering includes first hot isostatic pressing sintering, second hot isostatic pressing sintering and cooling carried out in sequence.

[0026] As a preferred technical solution of the present invention, the heating rate of the first hot isostatic pressing sintering is 5 to 10 °C / min, such as 5 °C / min, 6 °C / min, 7 °C / min, 8 °C / min, 9 °C / min or 10 °C / min, etc.

[0027] Preferably, the target temperature of the first hot isostatic pressing sintering is 1100 to 1200 °C, such as 1100 °C, 1120 °C, 1140 °C, 1150 °C, 1170 °C, 1190 °C or 1200 °C, etc.

[0028] Preferably, the target pressure of the first hot isostatic pressing sintering is 75 to 85 MPa, such as 75 MPa, 76 MPa, 78 MPa, 80 MPa, 81 MPa, 83 MPa or 85 MPa, etc.

[0029] Preferably, the heat preservation time of the first hot isostatic pressing sintering is 1 to 2 h, such as 1 h, 1.1 h, 1.3 h, 1.5 h, 1.6 h, 1.8 h or 2 h, etc.

[0030] Preferably, the heating rate of the second hot isostatic pressing sintering is 3-5 °C / min, such as 3 °C / min, 3.5 °C / min, 4 °C / min, 4.5 °C / min or 5 °C / min, etc.

[0031] Preferably, the target temperature of the second hot isostatic pressing sintering is 1450-1550 °C, such as 1450 °C, 1460 °C, 1480 °C, 1500 °C, 1510 °C, 1530 °C or 1550 °C, etc.

[0032] Preferably, the target pressure of the second hot isostatic pressing sintering is 145-155 MPa, such as 145 MPa, 147 MPa, 148 MPa, 150 MPa, 151 MPa, 153 MPa or 155 MPa, etc.

[0033] Preferably, the heat preservation time of the second hot isostatic pressing sintering is 3-5 h, such as 3 h, 3.5 h, 4 h, 4.5 h or 5 h, etc.

[0034] Preferably, the target temperature of the cooling is <200 °C.

[0035] As a preferred technical solution of the present invention, in step (2), the removal of the jacket includes: removing the surface jacket by grinding.

[0036] Preferably, in step (2), the machining includes: machining by using a diamond wire saw, an external cylindrical grinder, or an ultrasonic engraving machine.

[0037] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0038] (1) Prepare aluminum nitride powder with a purity of 99.0-99.9 wt% and a particle size of 0.8-1.2 μm, prepare a molybdenum mesh as an electrode member, and prepare a molybdenum heating wire or a molybdenum heating sheet as a heating member; obtain a ceramic green body by dry pressing.

[0039] Among them, the dry pressing is carried out in a dry pressing machine and includes the following steps:

[0040] Use die steel to make a mold to prevent deformation, fill the aluminum nitride powder to the bottom of the mold to form a first aluminum nitride layer, place the electrode member above the first aluminum nitride layer, fill the aluminum nitride powder above the electrode member and form a second aluminum nitride layer, perform the first step of dry pressing, the pressing pressure is 20-40 MPa, and the pressure holding time is 10-20 min.

[0041] Place a heating element above the formed body obtained by the first dry pressing. Fill aluminum nitride powder above the heating element to form a third aluminum nitride layer, and perform the second dry pressing. The pressing pressure is 40 - 50 MPa, and the pressure holding time is 10 - 20 min to obtain the green ceramic body;

[0042] (2) Put the green ceramic body obtained in step (1) into a jacket and seal it. Use a glass jacket with a softening temperature of 1200 - 1600 °C as the hot isostatic pressing jacket for aluminum nitride ceramics, and use argon as the protective gas;

[0043] In a hot isostatic pressing furnace, first perform the first hot isostatic pressing sintering. Heat it at a heating rate of 5 - 10 °C / min to 1100 - 1200 °C, and the pressure in the furnace is 75 - 85 MPa, and keep the temperature for 1 - 2 h; after the heat preservation of the first hot isostatic pressing sintering ends, perform the second hot isostatic pressing sintering. Heat it at a heating rate of 3 - 5 °C / min to 1450 - 1550 °C, and the pressure in the furnace is 145 - 155 MPa, and keep the temperature for 3 - 5 h; cool the furnace to a temperature < 200 °C and then take it out, and cool it down to room temperature;

[0044] After the obtained target blank is processed by grinding to remove the surface jacket, it is machined to obtain an aluminum nitride ceramic heater disk body.

[0045] The second object of the present invention is to provide an aluminum nitride ceramic heater disk body prepared by using the preparation method described in the first object.

[0046] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0047] (1) The preparation method of the present invention uses pure aluminum nitride powder without adding sintering aids. First, a green ceramic body is obtained by dry pressing, and then hot isostatic pressing sintering is carried out, so that the aluminum nitride powder is subjected to isotropic pressure, can fully flow and deform and eliminate pores, and achieve good densification of the aluminum nitride ceramic;

[0048] (2) The preparation method of the present invention can avoid the situation of uneven material density and poor densification in hot pressing sintering and pressureless sintering, and obtain an aluminum nitride disk body with good performance. It can not only effectively ensure the densification of the aluminum nitride ceramic, with the density reaching 99.5 - 99.9%, the grains of the aluminum nitride material are uniform, the appearance of the material has no color difference, and the density is uniform. It can ensure the thermal conductivity of the aluminum nitride ceramic, with the thermal conductivity ≥ 150 W / mK, and can ensure the flexural strength ≥ 300 MPa, meeting the use requirements. It can also simplify the operation steps and reduce the production cost. Description of the Drawings

[0049] Figure 1 It is a brief flow chart of the preparation method of the aluminum nitride ceramic heater disk body described in Embodiment 1 of the present invention;

[0050] In the figure: 1 - aluminum nitride powder; 2 - electrode component; 3 - heating component. Specific implementation manner

[0051] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation manners.

[0052] To better illustrate the present invention and facilitate understanding of its technical solution, typical but non-limiting embodiments of the present invention are as follows:

[0053] Embodiment 1

[0054] This embodiment provides a preparation method for a disk body of an aluminum nitride ceramic heater. Figure 1 A brief flow chart of this embodiment is shown. The preparation method includes dry pressing, hot isostatic pressing sintering, and machining in sequence. The preparation method includes the following steps:

[0055] (1) Prepare aluminum nitride powder with a purity of 99.3 wt% and a particle size of 1.0 μm, prepare a molybdenum mesh as the electrode component, and prepare a molybdenum heating sheet as the heating component; obtain a ceramic green body through dry pressing.

[0056] Among them, the dry pressing is carried out in a dry pressing machine and includes the following steps:

[0057] Use die steel to make a mold to prevent deformation. Fill the aluminum nitride powder to the bottom of the mold to form a first aluminum nitride layer. Place the electrode component above the first aluminum nitride layer. Fill aluminum nitride powder above the electrode component and form a second aluminum nitride layer. Carry out the first step of dry pressing. The pressing pressure is 30 MPa and the pressure holding time is 15 min.

[0058] Place the heating component above the formed body of the first step of dry pressing. Fill aluminum nitride powder above the heating component and form a third aluminum nitride layer. Carry out the second step of dry pressing. The pressing pressure is 45 MPa and the pressure holding time is 15 min to obtain the ceramic green body.

[0059] That is, as Figure 1 shown, the aluminum nitride powder 1 separates the electrode component 2 and the heating component 3 respectively.

[0060] (2) Put the ceramic green body in step (1) into a jacket and seal it. The jacket uses a glass jacket with a softening temperature of 1400 °C as the hot isostatic pressing jacket for aluminum nitride ceramics, and argon as the protective gas.

[0061] In a hot isostatic pressing furnace, first perform the first hot isostatic pressing sintering. Heat up at a heating rate of 8 °C / min to 1150 °C, with the furnace pressure being 80 MPa, and hold for 1.5 h. After the holding of the first hot isostatic pressing sintering ends, perform the second hot isostatic pressing sintering. Heat up at a heating rate of 4 °C / min to 1500 °C, with the furnace pressure being 150 MPa, and hold for 4 h. After furnace cooling to a temperature < 200 °C, take it out and cool down to room temperature.

[0062] After the obtained target blank is subjected to grinding to remove the surface jacket, it is machined to obtain an aluminum nitride ceramic heater disk body.

[0063] Example 2

[0064] This example provides a method for preparing an aluminum nitride ceramic heater disk body. Compared with Example 1, the difference is only that: the dry pressing and forming in step (1) is set as a one-step operation; the specific content is as follows:

[0065] The dry pressing and forming is carried out in a dry pressing machine and includes the following steps:

[0066] Use die steel to make a mold to prevent deformation. Fill aluminum nitride powder to the bottom of the mold to form a first aluminum nitride layer. Place an electrode part above the first aluminum nitride layer, fill aluminum nitride powder and form a second aluminum nitride layer, place a heating part, fill aluminum nitride powder and form a third aluminum nitride layer, and perform one-step dry pressing and forming as a whole. The pressing pressure is 45 MPa, and the pressure holding time is 30 min to obtain the ceramic green body.

[0067] Example 3

[0068] This example provides a method for preparing an aluminum nitride ceramic heater disk body. Compared with Example 1, the difference is only that: the hot isostatic pressing sintering in step (2) is set as a one-step operation; the specific content is as follows:

[0069] In a hot isostatic pressing furnace, perform one-step hot isostatic pressing sintering. Heat up at a heating rate of 4 °C / min to 1500 °C, with the furnace pressure being 150 MPa, and hold for 5.5 h. After furnace cooling to a temperature < 200 °C, take it out and cool down to room temperature.

[0070] Example 4

[0071] This example provides a method for preparing an aluminum nitride ceramic heater disk body. The preparation method includes dry pressing and forming, hot isostatic pressing sintering, and machining in sequence. The preparation method includes the following steps:

[0072] (1) Prepare aluminum nitride powder with a purity of 99.3 wt% and a particle size of 1.0 μm, prepare a molybdenum mesh as the electrode part, and prepare a molybdenum heating sheet as the heating part; obtain a ceramic green body through dry pressing and forming.

[0073] Among them, the dry pressing is carried out in a dry pressing machine, and it includes the following steps:

[0074] Use die steel to make the mold to prevent deformation. Fill aluminum nitride powder to the bottom of the mold to form a first aluminum nitride layer. Place an electrode part above the first aluminum nitride layer. Fill aluminum nitride powder above the electrode part and form a second aluminum nitride layer. Carry out the first dry pressing, with a pressing pressure of 20 MPa and a pressure holding time of 10 min;

[0075] Place a heating part above the formed body obtained from the first dry pressing. Fill aluminum nitride powder above the heating part and form a third aluminum nitride layer. Carry out the second dry pressing, with a pressing pressure of 40 MPa and a pressure holding time of 10 min to obtain the ceramic green body;

[0076] (2) Put the ceramic green body obtained in step (1) into a jacket and seal it. The jacket uses a glass jacket with a softening temperature of 1200 °C as the hot isostatic pressing jacket for aluminum nitride ceramics, and argon is used as the protective gas;

[0077] In a hot isostatic pressing furnace, first carry out the first hot isostatic pressing sintering. Heat up to 1100 °C at a heating rate of 5 °C / min, with the furnace pressure of 75 Mpa, and keep the temperature for 1 h; after the heat preservation of the first hot isostatic pressing sintering ends, carry out the second hot isostatic pressing sintering. Heat up to 1450 °C at a heating rate of 3 °C / min, with the furnace pressure of 145 MPa, and keep the temperature for 3 h; cool the furnace to a temperature < 200 °C and then take it out, and cool it down to room temperature;

[0078] After the obtained target blank is processed by grinding to remove the surface jacket, it is machined to obtain the aluminum nitride ceramic heater disk body.

[0079] Example 5

[0080] This example provides a preparation method of an aluminum nitride ceramic heater disk body. The preparation method includes dry pressing, hot isostatic pressing sintering, and machining carried out in sequence. The preparation method includes the following steps:

[0081] (1) Prepare aluminum nitride powder with a purity of 99.3 wt% and a particle size of 1.0 μm, prepare a molybdenum mesh as the electrode part, and prepare a molybdenum heating sheet as the heating part; obtain the ceramic green body through dry pressing;

[0082] Among them, the dry pressing is carried out in a dry pressing machine, and it includes the following steps:

[0083] Use die steel to make the die to prevent deformation. Fill aluminum nitride powder to the bottom of the die to form the first aluminum nitride layer. Place the electrode part above the first aluminum nitride layer. Fill aluminum nitride powder above the electrode part and form the second aluminum nitride layer. Carry out the first dry pressing forming, with the pressing pressure being 40 MPa and the pressure holding time being 20 min.

[0084] Place the heating part above the formed body obtained by the first dry pressing forming. Fill aluminum nitride powder above the heating part and form the third aluminum nitride layer. Carry out the second dry pressing forming, with the pressing pressure being 50 MPa and the pressure holding time being 20 min to obtain the green ceramic body.

[0085] (2) Put the green ceramic body described in step (1) into a jacket and seal it. The jacket uses a glass jacket with a softening temperature of 1600 °C as the hot isostatic pressing jacket for aluminum nitride ceramics, and argon is used as the protective gas.

[0086] In the hot isostatic pressing furnace, first carry out the first hot isostatic pressing sintering. Heat up at a heating rate of 10 °C / min to 1200 °C, with the furnace pressure being 85 Mpa, and keep the temperature for 2 h. After the heat preservation of the first hot isostatic pressing sintering ends, carry out the second hot isostatic pressing sintering. Heat up at a heating rate of 5 °C / min to 1550 °C, with the furnace pressure being 155 MPa, and keep the temperature for 5 h. Take it out after the furnace cools to a temperature < 200 °C and cool it down to room temperature.

[0087] After the obtained target blank removes the surface jacket by grinding and machining, an aluminum nitride ceramic heater disk body is obtained.

[0088] Comparative Example 1

[0089] This comparative example provides a preparation method of an aluminum nitride ceramic heater disk body. Compared with Example 1, the difference is only that: in step (1), aluminum nitride powder added with a sintering aid is used. The sintering aid is Y2O3 with a purity of 99.99%, and the mass of the sintering aid accounts for 5% of the mass of the aluminum nitride powder.

[0090] Respectively test the density, thermal conductivity, and flexural strength of the aluminum nitride ceramic heater disk bodies prepared in the above-mentioned example and comparative example. The specific test results are shown in Table 1.

[0091] Table 1

[0092] Item Density Thermal Conductivity (W / mK) Flexural Strength (MPa) Example 1 99.8％ 168 341 Example 2 99.6％ 143 339 Example 3 98.9％ 157 321 Example 4 99.5％ 163 338 Example 5 99.9％ 166 344 Comparative Example 1 99.7％ 162 340

[0093] In summary, the preparation method of the present invention uses pure aluminum nitride powder without adding sintering aids. First, a ceramic green body is obtained by dry pressing, and then hot isostatic pressing sintering is carried out, so that the aluminum nitride powder is subjected to isotropic pressure, can fully flow and deform, and the pores can be eliminated, realizing good densification of the aluminum nitride ceramic. The preparation method of the present invention can avoid the situation of uneven material density and poor densification in hot pressing sintering and pressureless sintering, and obtain an aluminum nitride disk body with good performance. It can not only effectively ensure the densification of the aluminum nitride ceramic, with the density reaching 99.5-99.9%, the grains of the aluminum nitride material are uniform, the appearance of the material has no color difference, and the density is uniform, but also ensure the thermal conductivity of the aluminum nitride ceramic, with the thermal conductivity ≥ 150 W / mK, and ensure the flexural strength ≥ 300 MPa, meeting the use requirements. It can also simplify the operation steps and reduce the production cost.

[0094] The present invention uses the above embodiments to illustrate the detailed structural features of the present invention. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of the components selected by the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0095] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0096] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0097] In addition, any combination can be made between different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing an aluminum nitride ceramic heater disk, characterized in that: The preparation method comprises the following steps: (1) preparing aluminum nitride powder, an electrode member, and a heating member, and obtaining a ceramic blank by dry pressing; (2) placing the ceramic blank of step (1) into a sheath and sealing it, and then performing hot isostatic pressing sintering, removing the sheath, and machining in sequence to obtain an aluminum nitride ceramic heater disk.

2. The preparation method according to claim 1, characterized in that: In step (1), the purity of the aluminum nitride powder is 99.0 to 99.9 wt %; Preferably, in step (1), the particle size of the aluminum nitride powder is 0.8 to 1.2 μm; Preferably, in step (1), the electrode member comprises a molybdenum mesh; Preferably, in step (1), the heating element comprises a molybdenum heating wire or a molybdenum heating plate.

3. The preparation method according to claim 1 or 2, characterized in that: In step (1), the dry pressing comprises the following steps: Prepare a mold, fill aluminum nitride powder to the bottom of the mold to form a first aluminum nitride layer, place an electrode member on the first aluminum nitride layer, fill aluminum nitride powder on the electrode member to form a second aluminum nitride layer, and perform the first step of dry pressing; A heating element is placed on the formed body formed by the first step of dry pressing, aluminum nitride powder is filled on the heating element to form a third aluminum nitride layer, and the second step of dry pressing is performed to obtain the ceramic blank.

4. The preparation method according to claim 3, characterized in that: The pressure of the first step of dry pressing is 20-40 MPa; Preferably, the holding time of the first step of dry pressing is 10 to 20 minutes; Preferably, the pressurizing pressure of the second step of dry pressing is 40-50 MPa; Preferably, the holding time of the second step of dry pressing is 10 to 20 minutes.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In step (2), the sheath adopts a glass sheath with a softening temperature of 1200-1600° C. as the hot isostatic pressing sheath of aluminum nitride ceramics, and argon is used as the protective gas.

6. The preparation method according to any one of claims 1 to 5, characterized in that: In step (2), the hot isostatic pressing sintering includes a first hot isostatic pressing sintering, a second hot isostatic pressing sintering and cooling performed in sequence.

7. The preparation method according to claim 6, characterized in that: The heating rate of the first hot isostatic pressing sintering is 5 to 10°C / min; Preferably, the target temperature of the first hot isostatic pressing sintering is 1100-1200°C; Preferably, the target pressure of the first hot isostatic pressing sintering is 75-85 MPa; Preferably, the holding time of the first hot isostatic pressing sintering is 1 to 2 hours; Preferably, the heating rate of the second hot isostatic pressing sintering is 3-5°C / min; Preferably, the target temperature of the second hot isostatic pressing sintering is 1450-1550°C; Preferably, the target pressure of the second hot isostatic pressing sintering is 145-155 MPa; Preferably, the holding time of the second hot isostatic pressing sintering is 3 to 5 hours; Preferably, the target temperature of the cooling is less than 200°C.

8. The preparation method according to any one of claims 1 to 7, characterized in that: In step (2), the removal of the coating comprises: removing the surface coating by grinding; Preferably, in step (2), the mechanical processing includes: processing using a diamond wire cutting machine, a cylindrical grinder, or an ultrasonic engraving machine.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: (1) preparing aluminum nitride powder with a purity of 99.0 to 99.9 wt% and a particle size of 0.8 to 1.2 μm, preparing a molybdenum mesh as an electrode member, and preparing a molybdenum heating wire or a molybdenum heating sheet as a heating member; and preparing a ceramic blank by dry pressing; Wherein, the dry pressing forming is carried out in a dry pressing forming machine, comprising the following steps: The mold is made of mold steel to prevent deformation, aluminum nitride powder is filled to the bottom of the mold to form a first aluminum nitride layer, an electrode is placed above the first aluminum nitride layer, aluminum nitride powder is filled above the electrode to form a second aluminum nitride layer, and the first step of dry pressing is performed, the pressure is 20-40 MPa, and the pressure holding time is 10-20 minutes; A heating element is placed on the first step dry pressing molded body, aluminum nitride powder is filled on the heating element to form a third aluminum nitride layer, and the second step dry pressing is performed, the pressure is 40-50 MPa, and the pressure holding time is 10-20 minutes to obtain the ceramic green body; (2) placing the ceramic blank of step (1) into a sheath and sealing it, wherein the sheath is a glass sheath with a softening temperature of 1200 to 1600° C. as a hot isostatic pressing sheath for aluminum nitride ceramics, and argon is used as a protective gas; In a hot isostatic pressing furnace, the first hot isostatic pressing sintering is first performed, the temperature is increased to 1100-1200°C at a heating rate of 5-10°C / min, the pressure in the furnace is 75-85MPa, and the temperature is kept for 1-2h; after the first hot isostatic pressing sintering is finished, the second hot isostatic pressing sintering is performed, the temperature is increased to 1450-1550°C at a heating rate of 3-5°C / min, the pressure in the furnace is 145-155MPa, and the temperature is kept for 3-5h; the furnace is cooled to a temperature of less than 200°C, then taken out and cooled to room temperature; The target blank is ground to remove the surface sheath, and then machined to obtain an aluminum nitride ceramic heater disc.

10. An aluminum nitride ceramic heater disk, characterized in that: The preparation method is described in any one of claims 1 to 9.

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