Powder material preparation device

Abstract

The utility model relates to the technical field of aluminum nitride powder preparation devices, in particular to a device structure suitable for preparing aluminum nitride powder by adopting a foaming method porous precursor, which can realize the carbon thermal reduction nitridation and carbon removal process. The powder material preparation device comprises a shell, an air inlet part, an air outlet adjusting part and a tray for placing reaction particles, the shell comprises a top cover, a middle shell and a lower shell which are detachably and hermetically connected from top to bottom, and the top cover, the middle shell and the lower shell are enclosed to form a closed reaction cavity; a plurality of layers of trays which are arranged up and down are detachably arranged in the middle shell; a plurality of vent holes of which the hole diameters and the number are changed layer by layer are formed in the trays; the lower shell is communicated with the gas inlet part and is used for enabling reaction gas to uniformly enter the reaction cavity to react with the reaction particles; the gas outlet adjusting part is arranged above the area, corresponding to the tray, of the shell and is used for selectively discharging gas in the reaction cavity.

Description

Technical Field

[0001] This utility model relates to the technical field of powder material preparation apparatus, specifically to a structure for a powder material preparation apparatus. It is particularly suitable for use in the carbothermic reduction nitriding reaction step and the decarburization reaction step of preparing high-quality aluminum nitride powder using a foamed porous precursor. Background Technology

[0002] With the rapid development of microelectronics technology, higher requirements are being placed on the heat dissipation performance of integrated circuit substrates, heat dissipation components, and electronic packaging materials. Aluminum nitride (AlN) is a covalent compound belonging to the hexagonal crystal system. It not only possesses high thermal conductivity but also exhibits excellent properties such as a coefficient of thermal expansion comparable to silicon (Si) and gallium arsenide (GaAs), high mechanical strength, excellent insulation properties, high temperature resistance, corrosion resistance, low dielectric loss, and non-toxicity. It has become one of the preferred materials for ultra-large-scale integrated circuit substrates. The preparation of high-purity AlN powder is a crucial prerequisite for obtaining high-performance aluminum nitride ceramics.

[0003] Currently, the main methods for preparing AlN powder include carbothermal reduction nitriding, direct nitriding of aluminum powder, self-propagating high-temperature synthesis, chemical vapor deposition, sol-gel method, and plasma synthesis.

[0004] Carbothermic reduction nitriding is a process in which aluminum and carbon sources react at high temperatures in a nitrogen atmosphere to produce aluminum nitride powder. It has advantages such as low cost, low reaction temperature, high reaction efficiency, wide applicability and good controllability, and is one of the most commonly used methods for preparing aluminum nitride powder.

[0005] In the conventional carbothermic reduction nitriding process, the high packing density of aluminum and carbon sources obstructs gas flow after it enters the powder, preventing uniform diffusion. This results in inconsistent reaction rates inside and outside the raw material powder, leading to poor purity and uniformity of the product and reduced finished quality. To address this issue, the most common methods are increasing the reaction temperature, extending the nitriding time, and increasing the nitrogen flow rate; however, these methods offer limited improvement.

[0006] Reports indicate that mechanical foaming was used to prepare porous precursors, which, combined with injection molding technology, produced larger-sized porous precursor bricks. This improved the flowability of the reactant gases and ensured sufficient contact between the gases and the powder. However, while this method improved the quality of aluminum nitride powder to some extent, there is still room for further improvement in the uniformity of the produced aluminum nitride powder. Utility Model Content

[0007] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a powder material preparation device, which attempts to break down the large-sized blocks obtained by mechanical foaming method and injection molding technology, significantly increase the powder loading, further increase the contact area between the reaction gas and the raw materials, and improve the uniformity of the powder, so as to solve the problem of poor product purity uniformity in the existing aluminum nitride preparation process.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a powder material preparation device, comprising a shell, an air inlet, an air outlet regulating part, and a tray for placing reaction particles; the shell comprises a top cover, a middle shell, and a lower shell that are detachably and sealingly connected from top to bottom, the top cover, the middle shell, and the lower shell forming a sealed reaction chamber; multiple layers of trays arranged vertically are detachably disposed inside the middle shell, and the trays are provided with multiple ventilation holes; the lower shell is connected to the air inlet for uniformly introducing reaction gas into the reaction chamber to react with the reaction particles; the air outlet regulating part is disposed above the corresponding area of ​​the trays on the shell for selectively discharging gas from the reaction chamber.

[0009] In one embodiment of this utility model, the size of the vent holes in each layer of the tray is slightly smaller than the size of the reaction particles placed in each layer; and / or, the reaction particles are porous aluminum nitride precursors prepared by a foaming method.

[0010] In one embodiment of this utility model, the number of vent holes in each layer of the tray gradually decreases from bottom to top; and / or, the diameter of the vent holes in each layer gradually increases from bottom to top.

[0011] In one embodiment of this utility model, the size of the vent hole of the tray is 0.25mm~10mm; and / or, the reaction particles are preferably 0.5mm-30mm.

[0012] In one embodiment of this utility model, the air intake includes an air intake pipe communicating with the lower housing and a flow reducer fixedly disposed relative to the air intake pipe. The flow reducer is configured to reduce the flow rate of the reaction gas entering the lower housing from the air intake pipe.

[0013] In one embodiment of this utility model, the flow-reducing component is an umbrella-shaped flow-reducing umbrella, which is disposed above the air intake pipe and covers the air intake pipe. The side wall of the air intake pipe is provided with a plurality of upwardly angled air guide holes for guiding the reaction gas in the air intake pipe to contact the flow-reducing umbrella.

[0014] In one embodiment of this utility model, the lower housing includes a bucket and a tube that are fixedly arranged. The bucket is arranged above the tube and the tube is sealed and connected to the air inlet. Multiple layers of baffles are fixedly arranged in the bucket. Each layer of the baffles is provided with multiple air inlets, and the air inlets between adjacent baffles do not overlap in the vertical direction.

[0015] In one embodiment of this utility model, the gas outlet regulating part includes a first gas outlet ring that is rotatably disposed and a second gas outlet ring that communicates with the reaction chamber. The first gas outlet ring is sleeved inside the second gas outlet ring. The first gas outlet ring and the second gas outlet ring are respectively provided with a plurality of mutually matching first gas outlet holes and second gas outlet holes. The second gas outlet ring is a middle shell, or the second gas outlet ring is fixedly disposed on the middle shell.

[0016] In one embodiment of this utility model, when the powder material preparation device is used in the carbothermic reduction nitridation reaction step, the reaction gas is N2 or NH3; wherein, the gas pressure of the reaction chamber is 10. -3 ~1MPa; the operating temperature should be 1400℃~1800℃; and / or, the powder material preparation device is made of one or more of graphite, aluminum nitride, silicon nitride, boron nitride ceramics or tungsten, molybdenum metal materials.

[0017] In one embodiment of this utility model, when the powder material preparation device is used in the decarbonization reaction step, the reaction gas is O2, CO2, or dry air; wherein, the gas pressure of the reaction chamber is atmospheric pressure; the operating temperature should not exceed 700℃; and / or, the powder material preparation device is made of one or more of aluminum nitride, silicon nitride, boron nitride, aluminum oxide, silicon dioxide, and zirconium oxide.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] (1) Based on the characteristic that the small pieces of the broken foamed porous precursor brick have a finer size distribution of about 0.5mm~30mm, by setting up multiple trays and setting multiple ventilation holes with progressively smaller size on the entire tray surface, the hole diameter is slightly smaller than the powder size to prevent the upper layer of powder from falling off. Under the same loading capacity, by uniformly loading it on each tray, the reaction degree of the reaction particles can be made more uniform, and at the same time, the reaction gas can be saved and the production cost can be reduced.

[0020] (2) The umbrella-shaped design in the air inlet significantly reduces the local gas flow rate, allowing the gas to diffuse from the air inlet hole of the air inlet channel at a uniform speed and evenly to the tray to fully react with the porous powder, promoting product consistency; the umbrella-shaped structure and baffle can effectively prevent the powder from falling and clogging the air inlet.

[0021] (3) Considering that the gas expands due to heat when it enters the furnace from the inlet, the funnel-shaped design at the bottom of the outer shell can make it diffuse evenly from bottom to top; the cylindrical shell in the middle can be disassembled independently and has a slot inside to ensure the bearing, replacement, loading and unloading of the tray; the top cover is detachable to facilitate the loading and unloading of powder; the design of the outlet hole / slot can ensure that the exhaust gas is discharged smoothly from the top. The outlet hole / slot is a double-layer structure. The amount of gas can be controlled by aligning or partially aligning the outlet holes / slots on the two layers, ensuring that the reaction gas has enough time to react with the powder, reducing the amount of gas used and the power consumption of the furnace, which has good economic benefits and is suitable for the mass production of AlN powder;

[0022] (4) This device fully utilizes the characteristic that gas can flow evenly and completely in the pores of porous foamed powder, and designs a device structure with porous vertical gas channels to improve the consistency of powder loading and product purity during carbothermic reduction nitriding and decarbonization. At the same time, the flowing gas can quickly remove gases such as CO and CO2 to prevent excessive reaction; the tray material is carbon-free or carbon-free, stable at high temperature and does not produce impurities, thus achieving efficient nitriding and decarbonization and improving product quality. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 is a physical image of the porous structure powder material used in an embodiment of the present invention, wherein (a) is a macroscopic view and (b) is a microscope view;

[0025] Figure 2 This is a schematic diagram of the structure of a powder material preparation apparatus provided in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the shell and air outlet structure provided in an embodiment of the present invention;

[0027] Figure 4 A schematic diagram of the tray portion provided in one embodiment of the present utility model;

[0028] Figure 5 This is a schematic diagram of the air intake and lower housing portions provided in an embodiment of the present invention.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Shell; 101. Top cover; 102. Middle shell; 112. Slot; 103. Lower shell; 113. Bucket section; 123. Tube section; 133. Baffle; 143. Air inlet;

[0031] 2. Tray; 201. Vent hole;

[0032] 3. Air intake section; 310, air intake pipe; 311, air intake passage; 312, air guide hole; 320, airflow reducer;

[0033] 4. Air outlet regulating section; 401. First air outlet ring; 402. Second air outlet ring. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model. In addition, it should be understood that the specific embodiments described herein are only used for illustration and explanation of the present utility model, and are not intended to limit the present utility model. In the present utility model, unless otherwise stated, directional terms such as "up," "down," "left," "right," "front," and "back" generally refer to up, down, left, and right in the actual use or working state of the device, specifically the drawing directions in the accompanying drawings.

[0035] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments of this utility model. Furthermore, the descriptions of each embodiment in the following embodiments have their own emphasis; for parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0036] Please refer to Figure 1- Figure 5This invention provides a powder material preparation apparatus, particularly suitable for use in the carbothermic reduction nitriding reaction step and decarburization reaction step in the preparation of aluminum nitride using a foaming method. The powder material preparation apparatus includes a shell 1, an air inlet 3, an air outlet regulating section 4, and trays 2 for placing reaction particles. The shell 1 is a hollow, sealed reaction chamber composed of a top cover 101, a middle shell 102, and a lower shell 103, which are detachably and sealingly connected from top to bottom. The air inlet 3 is located at the lower part of the shell 1 and communicates with the cavity of the shell 1, for introducing reaction gas into the cavity of the shell 1. The air outlet is located at the upper part of the shell 1 and communicates with the cavity of the shell 1, for discharging gas from the cavity of the shell 1, ensuring that the gas pressure inside the cavity of the shell 1 is within a set pressure range. Multiple trays 2 are arranged layer by layer from top to bottom within the cavity of the shell 1. The trays 2 are used to hold reaction particles with a porous structure, preferably, for example, porous precursors prepared by a foaming method as shown in Figure 1. More preferably, the reactant particles are porous precursors with a particle size of 0.5 mm to 30 mm. Porous precursors of this size can be obtained by crushing foamed porous precursor bricks or by preparing them directly. This application does not limit this.

[0037] Specifically, the housing 1 comprises three parts arranged from top to bottom: a top cover 101, a middle housing 102, and a lower housing 103. The top cover 101 and the middle housing 102 are detachably and sealingly connected. The middle housing 102 is located below the top cover 101 and is preferably cylindrical. The lower housing 103 is located below the middle housing 102 and is detachably and sealingly connected to the middle housing 102. The middle housing 102 is a hollow cavity. The inner wall of the middle housing 102 is provided with slots 112 for supporting trays 2, layer by layer from top to bottom. The number of slots 112 is not less than the number of trays 2, and preferably the number of slots 112 is the same as the number of trays 2. The advantage of this configuration is that by independently disassembling the middle shell 102 from the top cover 101 and the lower shell 103, and by providing a detachable slot 112 inside the middle shell 102, the multi-layer tray 2 can be well supported, replaced, loaded, and removed. At the same time, by setting the top cover 101 and the middle shell 102 to be detachably connected, it is also convenient to load and remove the reaction particles, thereby improving operational efficiency.

[0038] The upper part of the middle housing 102, preferably the area above the slot 112 of the middle housing 102, is fixedly connected to the air outlet regulating part 4. The air outlet regulating part 4 is used to adjust the amount of air outlet in the cavity of the middle housing 102, which will be described in detail later.

[0039] An air inlet 3 is sealed to the lower part of the lower housing 103, such as on the side wall or at the bottom. Preferably, the air inlet 3 is sealed to the bottom of the lower housing 103 to ensure that the gas input from the air inlet 3 enters the housing 1 uniformly. In a preferred embodiment, the lower housing 103 is preferably a funnel-shaped housing 1. The advantage of this design is that it takes into account the thermal expansion of the gas as it enters the housing 1 from the air inlet. The funnel-shaped design of the lower housing 103, which is the first part of the housing 1 to contact the reactant gas, can well match the thermal expansion characteristics of the reactant gas, thereby allowing the reactant gas to diffuse uniformly from bottom to top.

[0040] The shape of the tray 2 matches the internal structure of the middle shell 102. When the middle shell 102 is preferably cylindrical, the tray 2 is preferably circular. A number of trays 2 are provided, vertically layered, and each tray 2 has evenly distributed ventilation holes 201. That is, multiple layers of trays 2 are arranged from top to bottom within the middle shell 102.

[0041] The present invention does not limit the size of each layer of tray 2. In a preferred embodiment, the number of vents 201 in each layer of the multi-layered tray 2 gradually decreases from bottom to top, while the diameter of the vents 201 gradually increases from bottom to top. Simultaneously, the diameter of each vent 201 is slightly smaller than the size of the placed reaction particles to prevent the reaction particles from falling into the lower housing 103 while ensuring sufficient gas flow to fully contact the powder in the reaction particles. This arrangement allows for simultaneous contact and reaction between reaction particles of different sizes and the gas, and by ensuring that the reaction particles in different layers have different sizes, it guarantees sufficient contact and reaction between reaction particles of each size and the gas, while improving utilization efficiency. In another alternative embodiment, the number and size of the vent holes in each layer of tray 2 are consistent to accommodate reaction particles of the same size.

[0042] Preferably, since the size of the reactant particles is between 0.5 mm and 30 mm, the size of the vent 201 is preferably between 0.25 mm and 10 mm, and the size of the vent 201 on each tray 2 is slightly smaller than the size of the reactant particles.

[0043] When the powder material preparation apparatus provided by this utility model is used in the carbothermic reduction nitriding reaction step, N2 enters the lower shell 103 through the air inlet 3, and then diffuses layer by layer from bottom to top to each position of each tray 2, so that N2 can fully contact and react with the porous block, and the gas after reaction is discharged from the gas outlet regulating section 4. Preferably, the reaction temperature in the carbothermic reduction nitriding reaction is 1400℃~1800℃, preferably 1600℃, and the gas pressure is 10. -3 ~1MPa, preferably 0.1MPa, finally yields AlN powder with good uniformity.

[0044] It is understood that in the carbothermic reduction nitriding reaction, the gas entering the inlet section 3 can be any nitrogen-containing gas besides N2, and this invention does not impose any restrictions on this. In an alternative embodiment, when the device is used for the carbothermic reduction nitriding reaction, the introduced gas can be NH3.

[0045] Similarly, when the device is used for carbothermal reduction nitriding reaction, the material of the device can be one or more of carbon products (graphite (C)), ceramic products (aluminum nitride (AlN), boron nitride (BN), silicon nitride (Si3N4)), or metal products (tungsten (W), molybdenum (Mo)), and this utility model does not limit this.

[0046] When the powder material preparation apparatus provided by this utility model is used in the decarbonization reaction step, O2 enters the lower shell 103 through the air inlet 3, and then diffuses layer by layer from bottom to top to each position of each tray 2, so that O2 can fully contact and completely contact the carbon in the AlN powder, and the gas after reaction is discharged from the gas outlet regulating section 4. Preferably, the reaction temperature in the decarbonization reaction of the powder material preparation apparatus is 500~700℃, preferably 650℃, and the gas pressure is atmospheric pressure, finally obtaining high-purity and high-uniformity high-quality AlN powder.

[0047] It is understood that, in the decarbonization reaction, the gas entering through the inlet 3 can be any gas other than O2, and this invention does not impose any limitations on this. In an alternative embodiment, when the device is used for the decarbonization reaction, the introduced gas can be dry CO2 or air. Similarly, when the device is used for the decarbonization reaction, the material of the device can be one or more of the following: high-temperature resistant aluminum nitride (AlN), alumina (Al2O3), silicon dioxide (SiO2), silicon nitride (Si3N4), boron nitride (BN), and zirconium oxide (ZrO2). Similarly, when the device is used for the decarbonization reaction, microwave decarbonization can also be used as an auxiliary process.

[0048] Therefore, by fully utilizing the characteristic that gas can flow within the pores of foamed powder, and by arranging multiple layers of trays 2 in the middle shell 102—that is, by designing porous vertical gas channels—the consistency of powder loading and product purity during carbothermic reduction nitriding and decarbonization processes can be significantly improved. On one hand, considering the diverse particle size distribution of the reaction particles, especially the varying sizes of porous blocks, the design of multiple vertically distributed porous trays 2 maximizes the powder loading. On the other hand, by providing multiple holes on each tray 2, combined with the porous morphology of the reaction particles, gas can flow evenly from bottom to top to all locations, ensuring sufficient contact and reaction. Furthermore, since the gas enters from the lower shell 103 and exits from the gas outlet regulating section 4 at the top of the middle shell 102, the flowing gas can quickly carry away gases such as CO and CO2, improving reaction efficiency while preventing over-reaction.

[0049] It is understandable that in existing technologies, due to the excessively high packing density of aluminum and carbon sources, the flow of gas is obstructed after entering the powder, preventing uniform diffusion and resulting in inconsistent reaction levels inside and outside the raw material powder. This leads to poor purity and uniformity of the product, reducing the quality of the finished product. The improved mechanical foaming combined with injection molding typically produces larger blocks. This patent, by breaking down the blocks, further increases the contact area between the reacting gas and the raw material, improving powder uniformity. Through the solution of this invention, by setting up multiple layers of trays 2, each layer of tray 2 has multiple ventilation holes 201. With the same loading capacity, the reaction of the reacting particles is more uniform by uniformly loading them onto each layer of tray 2, while also effectively saving reacting gas and reducing production costs.

[0050] Please continue to refer to Figure 1 and... Figure 5 The intake section 3 will now be described in further detail. The intake section 3 includes an intake pipe 310 and a flow descender. An intake passage 311 is provided inside the intake pipe 310 to allow the reaction gas to enter. There are various reaction gases, such as N2 and NH3 in the carbothermic reduction nitridation reaction; and O2, CO2 or dry air in the decarbonization reaction, which will not be described in detail here.

[0051] A descending component is positioned above and fixed relative to the intake pipe 310. Preferably, the descending component is an umbrella-shaped descending umbrella 320, the umbrella surface of which can cover the intake pipe 310, and preferably, the umbrella surface size of the descending umbrella 320 is larger than that of the intake pipe 310. The intake pipe 310 is preferably a cylindrical structure with a sealed top, and multiple air guide holes 312 are evenly arranged on its sidewalls. The air passages of the air guide holes 312 are angled upwards to guide the reacting gas within the intake pipe 310 to contact the umbrella surface of the descending umbrella 320. Figure 5In this specific embodiment, the bottom of the air intake section 3 is an air intake channel 311, an umbrella-shaped descending umbrella 320 is provided above the air intake channel 311, and a cylindrical air intake pipe 310 is fixedly provided below it. The air intake channel 311 is provided inside the air intake pipe 310. The cylindrical air intake pipe 310 has evenly distributed air guide holes 312 on its side, and the air passages of the air guide holes 312 are obliquely upward to ensure that the gas enters the umbrella-shaped part.

[0052] The advantages of this design are twofold. First, the combination of the umbrella-shaped descending umbrella 320 and the air inlet pipe 310 significantly reduces the local gas velocity, lowering the gas velocity entering the lower housing 103 of the housing 1 from the air inlet channel 311. This allows the gas to diffuse uniformly and evenly from the air guide hole 312 of the air inlet channel 311 to the tray 2 to fully react with the reaction particles, promoting product consistency. Second, the umbrella-shaped structure effectively prevents reaction particles from falling and clogging the air guide hole 312 in the air inlet pipe 310.

[0053] Please continue reading. Figure 5 The lower housing 103 is a funnel-shaped housing 1, including a generally conical funnel portion 113 and a tube portion 123 disposed at the bottom. An air inlet 3 is disposed in the tube portion 123 of the lower housing 103. The funnel portion 113 of the lower housing 103 is provided with multiple layers of baffles 133 arranged from top to bottom. Each layer of baffles 133 is provided with an air inlet hole 143. The gaps between the air inlets 143 of adjacent baffles 133 do not overlap vertically, i.e., they do not overlap vertically. The advantage of this arrangement is that, on the one hand, it can better weaken and disperse the pressure of the reactive gas input into the air inlet pipe 310; on the other hand, by ensuring that the vertical positions of the baffles between adjacent layers do not overlap, it can effectively collect the reactive particles falling from the top and prevent them from falling further to the bottom.

[0054] The gas flow regulating unit 4 is used to regulate the gas flow rate inside the housing 1 and to discharge the gas inside the housing 1. In a preferred embodiment, the gas inside the housing 1 is discharged by periodically opening and closing. Figure 4In this replacement method, the gas outlet regulating unit 4 includes a first gas outlet ring 401 and a second gas outlet ring 402 that are sealed together. The first gas outlet ring 401 is fitted inside the second gas outlet ring 402. The second gas outlet ring 402 is connected to the reaction chamber of the housing 1. The first gas outlet ring 401 and the second gas outlet ring 402 are respectively provided with a plurality of matching first gas outlet holes and second gas outlet holes. The first gas outlet ring 401 can be rotated relative to the second gas outlet ring 402. By adjusting the relative positional relationship between the first gas outlet ring 401 and the second gas outlet ring 402, the size of the connection hole between the reaction chamber of the housing 1 and the external environment can be adjusted, thereby better regulating the gas flow rate inside the housing 1. The advantage of this configuration is that it can effectively control the amount of gas emitted, ensuring that the reaction gas has sufficient time to react with the reaction particles, reducing the amount of gas used and the power consumption of the entire device, resulting in good economic benefits, especially suitable for the mass production of AlN powder.

[0055] It is understood that the relative relationship between the second vent ring 402 and the middle shell 102 is not limited in this invention. In one specific embodiment, the second vent ring 402 is the middle shell 102, and the first vent ring 410 is sleeved inside the middle shell 102, so that the first vent ring 401 and the second vent ring 402 / middle shell 102 form a sleeve-like structure. The upper part of the middle shell 102 in the area where the slot 112 is provided is the second vent ring 402. In another alternative embodiment, the second vent ring 402 is fixedly disposed on the middle shell 102 and communicates with the reaction chamber of the shell 1.

[0056] In a preferred embodiment, tray 2 is made of a carbon-free or carbon-free volatile material, which is stable at high temperatures and does not produce impurities. This design allows for efficient nitriding and decarbonization, improving product quality. During CTRN (Carbon-to-Rich Density Reduction), the material is one or more of graphite, aluminum nitride, silicon nitride, boron nitride ceramics, or tungsten and molybdenum metals. During decarbonization, the material is one or more of aluminum nitride, silicon nitride, boron nitride, alumina, silicon dioxide, and zirconium oxide.

[0057] The present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

[0058] Throughout this specification, references to "an embodiment," "embodiment," or "specific embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention, but not necessarily in all embodiments. Therefore, the various representations of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout the specification do not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic of any specific embodiment of the present invention can be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the present invention described and illustrated herein may be based on the teachings herein and will be considered part of the spirit and scope of the present invention.

[0059] It should also be understood that one or more of the elements shown in the figures may be implemented in a more separate or more integrated manner, or may even be removed because they are inoperable in certain circumstances or provided because they may be useful for a particular application.

[0060] Furthermore, unless otherwise expressly stated, any arrows in the accompanying drawings should be considered illustrative only and not limiting. Additionally, unless otherwise stated, the term "or" as used herein is generally intended to mean "and / or". Where a term is anticipated to provide a separation or combination capability that is unclear, a combination of components or steps will also be considered as indicated.

Claims

1. A powder material preparation apparatus, characterized in that, It includes a housing, an air inlet, an air outlet regulating section, and a tray for holding reaction particles; The housing includes a top cover, a middle housing, and a lower housing that are detachably and sealed from top to bottom, and the top cover, middle housing, and lower housing together form a sealed reaction chamber. The middle shell is detachably provided with multiple layers of trays arranged vertically, and the trays are provided with multiple ventilation holes. The lower housing is connected to the air inlet, which is used to allow the reaction gas to enter the reaction chamber evenly and react with the reaction particles. The gas outlet regulating section is located above the area corresponding to the tray on the housing, and is used to selectively discharge the gas in the reaction chamber.

2. The powder material preparation apparatus according to claim 1, characterized in that, The size of the vent holes in each tray is slightly smaller than the size of the reaction particles placed in each layer; And / or, the reaction particles are porous aluminum nitride precursors prepared by a foaming method.

3. The powder material preparation apparatus according to claim 2, characterized in that, The number of ventilation holes in each layer of the tray gradually decreases from bottom to top; And / or, the pore size of the ventilation holes in each layer gradually increases from bottom to top.

4. The powder material preparation apparatus according to claim 2, characterized in that, The size of the ventilation holes in the tray is 0.25mm to 10mm; And / or, the reaction particles are preferably 0.5 mm to 30 mm.

5. The powder material preparation apparatus according to any one of claims 1-4, characterized in that, The air intake section includes an air intake pipe communicating with the lower housing and a flow reducer fixedly disposed relative to the air intake pipe. The flow reducer is configured to reduce the flow rate of the reaction gas entering the lower housing from the air intake pipe.

6. The powder material preparation apparatus according to claim 5, characterized in that, The flow descending component is an umbrella-shaped flow descending umbrella, which is positioned above and covers the air intake pipe. The side wall of the air intake pipe is provided with multiple upwardly angled air guide holes to guide the reaction gas in the air intake pipe to contact the flow descending umbrella.

7. The powder material preparation apparatus according to any one of claims 1-4, characterized in that, The lower housing includes a fixedly arranged bucket and a pipe. The bucket is located above the pipe and is sealed and connected to the air inlet. The bucket has multiple layers of baffles arranged vertically. Each layer of baffles has multiple air inlets, and the air inlets between adjacent baffles do not overlap in the vertical direction.

8. The powder material preparation apparatus according to any one of claims 1-4, characterized in that, The gas outlet regulating part includes a first gas outlet ring that is rotatably disposed and a second gas outlet ring that communicates with the reaction chamber. The first gas outlet ring is sleeved inside the second gas outlet ring. The first gas outlet ring and the second gas outlet ring are respectively provided with a plurality of matching first gas outlet holes and second gas outlet holes. The second vent ring is either a middle shell or the second vent ring is fixedly mounted on the middle shell.

9. The powder material preparation apparatus according to any one of claims 1-4, characterized in that, When the powder material preparation device is used in the carbothermic reduction nitridation reaction step, the reaction gas is N2 or NH3; The gas pressure in the reaction chamber is 10. -3 ~1MPa; operating temperature should be 1400℃~1800℃.

10. The powder material preparation apparatus according to any one of claims 1-4, characterized in that, When the powder material preparation device is used in the decarbonization reaction step, the reaction gas is O2, CO2, or dry air. The gas pressure in the reaction chamber is atmospheric pressure; the operating temperature should not exceed 700℃.

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