Sintering method and sintering device for aluminum nitride thin-wall pipe
By setting up a synchronously shrinkable bottom liner plate at the bottom of the aluminum nitride thin-walled pipe and filling the embedded powder in the pipe, the problems of deformation, cracking and insufficient density during the sintering process are solved, and more uniform heat conduction and synchronous shrinkage are achieved, and the quality and stability of the pipe are improved.
Patent Information
- Application Number
- CN202411753709.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-02
- Publication Date
- 2025-03-04
AI Technical Summary
During the sintering process, aluminum nitride thin-walled pipes are prone to deformation and cracking due to uneven heat field temperature, inconsistent material shrinkage and gravity, and it is difficult to achieve net size forming.
A sintering method is adopted to ensure that the tube is heated uniformly by setting a bottom liner plate on the bottom liner plate at the bottom liner plate to shrink synchronously with the bottom liner plate, and fill the pipe with embedded powder to conduct heat evenly to ensure that the tube is heated consistently.
Effectively prevent aluminum nitride pipes from deforming due to different shrinkage rates, reduce cracking, and improve the density of the pipes.
Smart Images
Figure CN119551990A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of aluminum nitride tube processing, and in particular to a sintering method and a sintering device for aluminum nitride thin-wall tubes. Background Art
[0002] Aluminum nitride has high thermal conductivity, high insulation, high strength and a thermal expansion coefficient close to that of silicon. It is widely used in high-power integrated circuits, module circuits, microelectronics, optics, communications, electrical devices and intelligent manufacturing. Aluminum nitride pipes are widely used in the manufacture of high-power insulated gate bipolar transistor (IGBT) modules due to their light weight, high temperature resistance, good thermal conductivity and strong insulation, achieving high heat dissipation capacity and high power density; they are used in semiconductor equipment to resist fluoride and plasma corrosion. At present, the main forming method of aluminum nitride thin-walled pipes is dry pressing. This process has the advantages of simple operation, fewer process steps and high efficiency, but it cannot press complex geometric shapes. Post-processing is required and it is difficult to form the net size.
[0003] Aluminum nitride thin-walled tubes are generally made through processes such as green billet preparation, debinding, and sintering. The preparation process of aluminum nitride thin-walled tubes is complicated, and the main problems are as follows: the wall thickness of aluminum nitride thin-walled tubes is about 1mm, which is an ultra-thin cavity structure. It is difficult to form in one time, and the inner and outer diameters need to have a large processing allowance, and the dimensional accuracy is poor; during the debinding and sintering process, if the placement direction is improper, aluminum nitride thin-walled tubes are prone to deformation, cracking and other problems; during the sintering process, the debinding parts are placed vertically in the sintering furnace. Due to factors such as uneven thermal field temperature, inconsistent material shrinkage, and the gravity of the tube itself, the deformation of different positions of the tube is different, resulting in deformation, cracking and other problems of the tube. At the same time, the density of the tube itself will also be affected to a certain extent. Summary of the invention
[0004] In view of this, it is necessary to provide a sintering method for aluminum nitride thin-walled tubes to reduce tube deformation and cracking and improve tube density.
[0005] It is also necessary to provide a sintering apparatus for aluminum nitride thin-walled tubes.
[0006] A sintering method for aluminum nitride thin-walled tubes comprises the following steps:
[0007] Step S11: preparing an aluminum nitride thin-walled tube green piece and a base lining plate green piece, wherein the aluminum nitride thin-walled tube green piece and the base lining plate green piece have the same density and the same composition;
[0008] Step S12: evenly spraying boron nitride powder on the surface of the base lining plate green piece and the pipe green piece to debind, thereby obtaining a base lining plate debinding piece and a pipe debinding piece;
[0009] Step S13: placing the bottom lining plate debinding piece into a container, and placing the aluminum nitride thin-walled pipe debinding piece on the bottom lining plate debinding piece;
[0010] Step S14: Pour the calcined powder into the container to fill the gap between the aluminum nitride thin-walled tube debonding part and the container.
[0011] Step S15: placing the container containing the aluminum nitride thin-walled tube debinding parts into a sintering furnace to sinter them into aluminum nitride thin-walled tubes.
[0012] A sintering device for aluminum nitride thin-walled tubes comprises a tube box and a box cover. The tube box comprises a plurality of mold cavities and a mold core. A heat flow channel is provided between two adjacent mold cavities for better heat transfer. The mold core is located at the center of the mold cavity. The diameter of the mold core is smaller than the inner diameter of the thin-walled tube. Buried sintering powder is filled between the mold core and the thin-walled tube. The box cover is connected to the tube box sleeve. The box cover is provided with a plurality of pipe sleeves, which match the mold cavity. The inner diameter of the pipe sleeve is the same as the outer diameter of the thin-walled tube. The upper end of the pipe sleeve is open to allow the buried sintering powder to pass through.
[0013] Preferably, a heat flow hole is provided at the bottom of the mold core so that the mold core can be heated from the bottom.
[0014] Preferably, the tube box and the box cover are made of high-temperature resistant heat-conductive material.
[0015] Beneficial effects: The sintering method of the aluminum nitride thin-walled tube of the present invention arranges a bottom liner at the bottom of the aluminum nitride thin-walled tube so that the aluminum nitride thin-walled tube and the bottom liner keep shrinking synchronously, thereby preventing the aluminum nitride tube from deforming due to different shrinkage rates between the upper and lower parts of the aluminum nitride tube. Furthermore, by filling the aluminum nitride thin-walled tube with buried sintering powder, the aluminum nitride thin-walled tube is heated evenly and shrinks uniformly, and the aluminum nitride thin-walled tube is prevented from cracking due to uneven heating.
[0016] The sintering device for aluminum nitride thin-walled tubes of the present invention can ensure that the thickness of the buried sintered powder distributed around the aluminum nitride thin-walled tubes is the same, so that the heat is conducted from the buried sintered powder to the aluminum nitride thin-walled tubes more evenly, and the deformation and cracking problems of the thin-walled tubes are effectively controlled, thereby improving the density of the thin-walled tubes. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a schematic structural diagram of the tube box and the box cover of the sintering device for aluminum nitride thin-walled tubes of the present invention being separated.
[0018] Figure 2 This is a schematic diagram of placing the sintering device for aluminum nitride thin-walled tubes of the present invention on a furnace lining.
[0019] Figure 3The schematic diagram of the tube box and the box cover of the sintering device for aluminum nitride thin-walled tubes of the present invention is viewed from an upward angle.
[0020] Figure 4 This is a schematic diagram of the tube box of the present invention after the thin-walled tube is placed.
[0021] Figure 5 for Figure 4 Cross-sectional view of .
[0022] In the figure: a sintering device 10 for aluminum nitride thin-walled tubes, a tube box 20, a mold cavity 201, a mold core 202, a heat flow channel 203, a heat flow hole 204, a box cover 30, a tube sleeve 301, and a thin-walled tube 40. DETAILED DESCRIPTION
[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0024] The sintering method of the aluminum nitride thin-walled tube 40 comprises the following steps:
[0025] Step S11: Prepare the aluminum nitride thin-walled tube 40 green blank and the base liner green blank. The density of the aluminum nitride thin-walled tube 40 green blank is the same as that of the base liner green blank, the same composition, and the same debinding method. In this way, the aluminum nitride thin-walled tube 40 debinding part and the base liner debinding part can shrink synchronously during high-temperature sintering, so that the deformation of each part of the aluminum nitride thin-walled tube 40 is consistent.
[0026] In a preferred embodiment, the components of the aluminum nitride thin-walled tube 40 green body include aluminum nitride, yttrium oxide, and organic matter, wherein the mass ratio of aluminum nitride to yttrium oxide is (1-2):1.
[0027] In a preferred embodiment, the wall thickness of the green piece of the aluminum nitride thin-walled tube 40 is greater than 1 mm, and the thickness of the green piece of the base liner is 1 to 5 mm.
[0028] Step S12: Evenly spray boron nitride powder on the surface of the base liner green piece and the tube green piece to remove binder, and obtain base liner debinding pieces and tube debinding pieces. Spraying boron nitride powder can prevent the base liner green piece and the aluminum nitride thin-walled tube 40 green piece from sticking during the sintering process. At the same time, the boron nitride powder can lubricate the aluminum nitride thin-walled tube 40, reducing the friction caused by contraction between the aluminum nitride thin-walled tube 40 debinding piece and the base liner debinding piece.
[0029] Step S13: placing the bottom lining plate debonding piece into a container, and placing the aluminum nitride thin-walled tube 40 debonding piece on the bottom lining plate debonding piece;
[0030] Step S14: Pour the sintering powder into the container to fill the gap between the aluminum nitride thin-walled tube 40 and the container. In this way, during the sintering process, heat is transferred from the sintering powder to the aluminum nitride thin-walled tube 40, so that the aluminum nitride thin-walled tube 40 is heated more evenly, and the sintering powder can inhibit the aluminum nitride thin-walled tube 40 from shrinking and deforming.
[0031] Step S15: placing the container containing the aluminum nitride thin-walled tube 40 debonding parts into a sintering furnace to sinter the aluminum nitride thin-walled tube 40 .
[0032] In a preferred embodiment, in step S1, the aluminum nitride thin-walled tube 40 green body is pressed by dry pressing and isostatic pressing.
[0033] In a preferred embodiment, in step S1, the preparation method for placing a backing plate green piece with a diameter greater than 100 mm comprises the following steps:
[0034] Step S21: Pressing the raw material powder into a pre-pressed green body with a thickness of 1 to 5 mm by dry pressing, with a pressing pressure of less than 10 MPa;
[0035] Step S22: the pre-pressed green body is further pressed by isostatic pressing to form a base liner green body with a thickness of 1 to 5 mm.
[0036] In a preferred embodiment, in step S1, the preparation method for placing a green piece of a backing plate having a diameter less than or equal to 100 mm comprises the following steps:
[0037] Step S31: pressing the raw material powder into a rod by isostatic pressing;
[0038] Step S32: Cut the rod into thin slices with a thickness of 1 to 5 mm to form a base liner green piece.
[0039] In a preferred embodiment, the density error between the green aluminum nitride thin-walled tube 40 and the green base liner is less than 0.3%.
[0040] Please see Figures 1 to 5A sintering device 10 for aluminum nitride thin-walled tubes includes a tube box 20 and a box cover 30. The tube box 20 includes a plurality of mold cavities 201 and a mold core 202. A heat flow channel 203 is provided between two adjacent mold cavities 201 for better heat transfer. The mold core 202 is located at the center of the mold cavity 201. The diameter of the mold core 202 is smaller than the inner diameter of the thin-walled tube 40. The mold core 202 and the thin-walled tube 40 are filled with buried sintering powder. The box cover 30 is sleeve-connected with the tube box 20. The box cover 30 is provided with a plurality of pipe sleeves 301. The pipe sleeves 301 match the mold cavity 201. The inner diameter of the pipe sleeves 301 is the same as the outer diameter of the thin-walled tube 40. The upper end of the pipe sleeves 301 is open to allow the buried sintering powder to pass through.
[0041] When in use, firstly, the tube box 20 and the box cover 30 are engaged, and then the burying powder is poured into the through hole above the box cover 30. After the burying powder is fully filled, the box cover 30 can be opened, and the burying powder is filled into the gap between the mold cavity 201 and the thin-walled tube 40, and the tube box 20 and the box cover 30 are placed in the sintering furnace for sintering. In this way, the thin-walled tube is enclosed in the sintering device, and the heat is more uniform, and the sintering quality is better.
[0042] The heat flow channels 203 between the mold cavities 201 can quickly conduct heat to the mold cavities 201 , so that the mold cavities 201 are quickly heated.
[0043] Since the heat is conducted to the thin-walled tube 40 through the tube box 20, the box cover 30 and the buried burning powder, the heat conduction efficiency is relatively low. Therefore, in a preferred embodiment, a heat flow hole 204 is provided at the bottom of the core 202 so that the core 202 can be heated from the bottom. In this way, the heat can heat the core 202 from the bottom of the core 202, and then heat the buried burning powder. The heating area of the tube box 20 is significantly increased, so the heat can be conducted to the buried burning powder faster, and then heat the debonding parts of the thin-walled tube 40.
[0044] In a preferred embodiment, the pipe box 20 and the box cover 30 are made of high temperature resistant heat conductive material.
[0045] The following are examples of the present invention and comparative examples.
[0046] Embodiment 1
[0047] Prepare an aluminum nitride thin-walled tube 40 green piece and a base liner green piece. The aluminum nitride thin-walled tube 40 green piece has the same composition as the base liner green piece. The aluminum nitride thin-walled tube 40 green piece has a diameter of 50 mm, a height of 300 mm, and a density of 1.88 g / cm 3 The thickness of the green part of the backing plate is 2 mm and the density is 1.91 g / cm 3. Spray boron nitride powder evenly on the surface of the base lining green parts and the tube green parts to debind and obtain base lining debinding parts and tube debinding parts. Put the base lining debinding parts into a container, and place the aluminum nitride thin-walled tube 40 debinding parts on the base lining debinding parts; cover the box cover 30 on the tube box 20, and place the aluminum nitride thin-walled tube 40 debinding parts from the top of the box cover 30 into the tube box 20, and place them on the base lining debinding parts; fill the gap between the aluminum nitride thin-walled tube 40 debinding parts and the container with buried sintering powder (boron nitride: aluminum nitride: yttrium oxide = 2:1:0.05); put the tube box 20 into a sintering furnace and sinter it into an aluminum nitride thin-walled tube 40. The obtained aluminum nitride thin-walled tube 40 has a density of 3.340g / cm 3 , the circularity is 0.99 and the straightness is 0.1%.
[0048] Embodiment 2
[0049] Prepare an aluminum nitride thin-walled tube 40 green piece and a base liner green piece. The aluminum nitride thin-walled tube 40 green piece has the same composition as the base liner green piece. The aluminum nitride thin-walled tube 40 green piece has a diameter of 110 mm, a height of 300 mm, and a density of 1.86 g / cm 3 The thickness of the green part of the backing plate is 2 mm and the density is 1.91 g / cm 3 . Spray boron nitride powder evenly on the surface of the base lining green parts and the tube green parts to debind and obtain base lining debinding parts and tube debinding parts. Put the base lining debinding parts into a container, and place the aluminum nitride thin-walled tube 40 debinding parts on the base lining debinding parts; cover the box cover 30 on the tube box 20, and place the aluminum nitride thin-walled tube 40 debinding parts from the top of the box cover 30 into the tube box 20, and place them on the base lining debinding parts; fill the gap between the aluminum nitride thin-walled tube 40 debinding parts and the container with buried sintering powder (boron nitride: aluminum nitride: yttrium oxide = 2:1:0.05); put the tube box 20 into a sintering furnace and sinter it into an aluminum nitride thin-walled tube 40. The obtained aluminum nitride thin-walled tube 40 has a density of 3.298g / cm 3 , the circularity is 0.96 and the straightness is 0.25%.
[0050] Embodiment 3
[0051] Prepare an aluminum nitride thin-walled tube 40 green piece and a base liner green piece. The aluminum nitride thin-walled tube 40 green piece has the same composition as the base liner green piece. The aluminum nitride thin-walled tube 40 green piece has a diameter of 50 mm, a height of 300 mm, and a density of 1.88 g / cm 3 The thickness of the green part of the backing plate is 2 mm and the density is 1.91 g / cm 3. Spray boron nitride powder evenly on the surface of the base lining green parts and the tube green parts to debind and obtain base lining debinding parts and tube debinding parts. Put the base lining debinding parts into a container, and place the aluminum nitride thin-walled tube 40 debinding parts on the base lining debinding parts; cover the box cover 30 on the tube box 20, and place the aluminum nitride thin-walled tube 40 debinding parts from the top of the box cover 30 into the tube box 20, and place them on the base lining debinding parts; fill the gap between the aluminum nitride thin-walled tube 40 debinding parts and the container with buried sintering powder (boron nitride: aluminum nitride: yttrium oxide = 3:1:0.05); put the tube box 20 into a sintering furnace and sinter it into an aluminum nitride thin-walled tube 40. The obtained aluminum nitride thin-walled tube 40 has a density of 3.312g / cm 3 , the circularity is 0.92, and the straightness is 0.48%.
[0052] Embodiment 4
[0053] Prepare an aluminum nitride thin-walled tube 40 green piece and a base liner green piece. The aluminum nitride thin-walled tube 40 green piece has the same composition as the base liner green piece. The aluminum nitride thin-walled tube 40 green piece has a diameter of 50 mm, a height of 300 mm, and a density of 1.88 g / cm 3 The green part of the backing plate has a thickness of 4 mm and a density of 1.89 g / cm 3 . Spray boron nitride powder evenly on the surface of the base lining green parts and the tube green parts to debind and obtain base lining debinding parts and tube debinding parts. Put the base lining debinding parts into a container, and place the aluminum nitride thin-walled tube 40 debinding parts on the base lining debinding parts; cover the box cover 30 on the tube box 20, and place the aluminum nitride thin-walled tube 40 debinding parts from the top of the box cover 30 into the tube box 20, and place them on the base lining debinding parts; fill the gap between the aluminum nitride thin-walled tube 40 debinding parts and the container with buried sintering powder (boron nitride: aluminum nitride: yttrium oxide = 2:1:0.05); put the tube box 20 into a sintering furnace and sinter it into an aluminum nitride thin-walled tube 40. The obtained aluminum nitride thin-walled tube 40 has a density of 3.316g / cm 3 , the circularity is 0.95, and the straightness is 0.32%.
[0054] Comparative Example 1
[0055] Preparation of 40 green pieces of aluminum nitride thin-walled tubes with a diameter of 50 mm, a height of 300 mm, and a density of 1.88 g / cm 3 The surface of the green tube is uniformly sprayed with boron nitride powder to remove binder and obtain a tube debinding part. The aluminum nitride thin-walled tube 40 is placed in the tube box 20, the box cover 30 is placed on the tube box 20, and the tube box 20 is directly placed in a sintering furnace to be fired into the aluminum nitride thin-walled tube 40. The obtained aluminum nitride thin-walled tube 40 has a density of 3.280 g / cm 3 , the circularity is 0.85 and the straightness is 1%.
[0056] Comparative Example 2
[0057] Preparation of 40 green pieces of aluminum nitride thin-walled tubes with a diameter of 50 mm, a height of 300 mm, and a density of 1.88 g / cm 3 . Spray boron nitride powder evenly on the surface of the green tube to remove binder and obtain a tube debinding part. Put the aluminum nitride thin-walled tube 40 into the tube box 20, cover the box cover 30 on the tube box 20, fill the gap between the aluminum nitride thin-walled tube 40 debinding part and the container with buried sintering powder (boron nitride: aluminum nitride: yttrium oxide = 2:1:0.05), put it into a sintering furnace and sinter it into aluminum nitride thin-walled tube 40. The obtained aluminum nitride thin-walled tube 40 has a density of 3.302g / cm 3 , the circularity is 0.89 and the straightness is 0.65%.
[0058] Comparative Example 3
[0059] Prepare an aluminum nitride thin-walled tube 40 green piece and a base liner green piece. The aluminum nitride thin-walled tube 40 green piece has the same composition as the base liner green piece. The aluminum nitride thin-walled tube 40 green piece has a diameter of 50 mm, a height of 300 mm, and a density of 1.88 g / cm 3 The thickness of the green part of the backing plate is 2 mm and the density is 1.91 g / cm 3 . Spray boron nitride powder evenly on the surface of the base lining green parts and the tube green parts to debind and obtain base lining debinding parts and tube debinding parts. Put the base lining debinding parts into a container, and place the aluminum nitride thin-walled tube 40 debinding parts on the base lining debinding parts; put the box cover 30 on the tube box 20, and place the aluminum nitride thin-walled tube 40 debinding parts from the top of the box cover 30 into the tube box 20, and place them on the base lining debinding parts; put the tube box 20 into a sintering furnace to sinter into aluminum nitride thin-walled tube 40. The obtained aluminum nitride thin-walled tube 40 has a density of 3.286g / cm 3 , the circularity is 0.86 and the straightness is 0.9%.
[0060] 100 pieces of each embodiment or comparative example were fired, and the experimental results are shown in Table 1:
[0061] Table 1: Test results of aluminum nitride thin-walled tube 40
[0062] Pipe deformation Pipe cracking Density / % Embodiment 1 1 piece deformation No cracking 99.70 Embodiment 2 2 pieces of deformation No cracking 98.45 Embodiment 3 3 pieces of deformation No cracking 98.87 Embodiment 4 2 pieces of deformation No cracking 98.99 Comparative Example 1 20 pieces of deformation 20 pieces cracked 97.91 Comparative Example 2 8 pieces of deformation 8 pieces cracked 98.57 Comparative Example 3 10 pieces of deformation 10 pieces cracked 98.09
[0063] The experimental results of Example 1, Example 2, Example 3 and Example 4 show that the sintering method of the aluminum nitride thin-walled tube 40 of the present invention has high stability in production and high feasibility.
[0064] The experimental results of Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 show that the sintering method of the aluminum nitride thin-walled tube 40 of the present invention can significantly reduce the deformation and cracking problems of the thin-walled tube 40, and at the same time, the density is significantly improved.
[0065] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.
Claims
1. A sintering method for aluminum nitride thin-walled tubes, characterized in that: The following steps are involved: Step S11: preparing an aluminum nitride thin-walled tube green piece and a base lining plate green piece, wherein the aluminum nitride thin-walled tube green piece and the base lining plate green piece have the same density and the same composition; Step S12: evenly spraying boron nitride powder on the surface of the base lining plate green piece and the pipe green piece to debind, thereby obtaining a base lining plate debinding piece and a pipe debinding piece; Step S13: placing the bottom lining plate debinding piece into a container, and placing the aluminum nitride thin-walled pipe debinding piece on the bottom lining plate debinding piece; Step S14: Pour the calcined powder into the container to fill the gap between the aluminum nitride thin-walled tube debonding part and the container; Step S15: placing the container containing the aluminum nitride thin-walled tube debinding parts into a sintering furnace to sinter them into aluminum nitride thin-walled tubes.
2. The sintering method of aluminum nitride thin-walled tube according to claim 1, characterized in that: In step S11, the components of the aluminum nitride thin-walled tube green body include aluminum nitride, yttrium oxide, boron nitride, and organic matter, wherein the mass ratio of aluminum nitride to yttrium oxide is (1-2):
1.
3. The sintering method of aluminum nitride thin-walled tube according to claim 1, characterized in that: In step S11, the thickness of the prepared aluminum nitride thin-walled tube green piece is greater than 1 mm, and the thickness of the bottom liner green piece is 1-5 mm.
4. The sintering method of aluminum nitride thin-walled tube according to claim 1, characterized in that: In step S1, the aluminum nitride thin-walled tube green body is pressed by dry pressing, pre-pressing and isostatic pressing.
5. The sintering method of aluminum nitride thin-walled tube according to claim 1, characterized in that: In step S1, the preparation method for placing a backing plate green piece with a diameter greater than 100 mm comprises the following steps: Step S21: Pressing the raw material powder into a pre-pressed green body with a thickness of 1 to 5 mm by dry pressing, with a pressing pressure of less than 10 MPa; Step S22: the pre-pressed green body is further pressed by isostatic pressing to form a base liner green body with a thickness of 1 to 5 mm.
6. The sintering method of aluminum nitride thin-walled tube according to claim 1, characterized in that: In step S1, the preparation method for placing a backing plate green piece with a diameter less than or equal to 100 mm includes the following steps: Step S31: pressing the raw material powder into a rod by isostatic pressing; Step S32: Cut the rod into thin slices with a thickness of 1 to 5 mm to form a base liner green piece.
7. The sintering method of aluminum nitride thin-walled tube according to claim 1, characterized in that: The density error of the aluminum nitride thin-walled tube green parts and the base liner green parts is less than 0.2%.
8. A sintering device for aluminum nitride thin-walled tubes, characterized in that: It includes a tube box and a box cover. The tube box includes a plurality of mold cavities and mold cores. A heat flow channel is provided between two adjacent mold cavities for better heat transfer. The mold core is located at the center of the mold cavity. The diameter of the mold core is smaller than the inner diameter of the thin-walled tube. Buried burning powder is filled between the mold core and the thin-walled tube. The box cover is connected to the tube box sleeve. The box cover is provided with a plurality of pipe sleeves. The pipe sleeves match the mold cavity. The inner diameter of the pipe sleeves is the same as the outer diameter of the thin-walled tube. The upper end of the pipe sleeves is open to allow the buried burning powder to pass through.
9. The sintering device for aluminum nitride thin-walled tubes according to claim 8, characterized in that: The bottom of the mold core is provided with a heat flow hole so that the mold core can be heated from the bottom.
10. The sintering device for aluminum nitride thin-walled tubes according to claim 8, characterized in that: The pipe box and the box cover are made of high-temperature resistant heat-conducting material.