Aluminum nitride powder preparation device and preparation process thereof

Abstract

The application relates to the technical field of aluminum nitride powder preparation, and particularly discloses an aluminum nitride powder preparation device and a preparation process thereof, which comprises a bottom plate, two mounting racks are fixedly installed on the top surface of the bottom plate, a rotating frame is rotatably installed between the two mounting racks through a rotating shaft, two opposite inner walls in the rotating frame are both rotatably installed with mounting shafts, and the ends of the two mounting shafts close to each other are jointly fixedly connected with a rotating ring arranged in an inclined mode. The grinding barrel is driven by the switching assembly to adjust the inclination with the axis center, so that the raw material powder can be subjected to step-by-step ball milling in the two grinding cavities in sequence, the particle size of the raw material powder is rapidly reduced under the action of large grinding media, the total ball milling time is reduced, the occurrence of cold welding is reduced, the raw material powder is subjected to high-precision ball milling through small grinding media, the raw material powder is further refined, the influence of cold welding on the ball milling quality is reduced, and the agglomeration phenomenon is reduced.

Description

Technical Field

[0001] This invention relates to the field of aluminum nitride powder preparation technology, specifically to an aluminum nitride powder preparation apparatus and its preparation process. Background Technology

[0002] Aluminum nitride is an inorganic non-metallic material with unique physical and chemical properties. Due to its high thermal conductivity and good electrical insulation, it is often used to manufacture substrates for high-power electronic devices. Its excellent mechanical strength and wear resistance make aluminum nitride ceramics promising for applications in aerospace, transportation and other fields. Currently, aluminum nitride powder is usually prepared by carbonization reduction or high-energy ball milling. High-energy ball milling refers to reducing the size of powder particles and increasing the specific surface area of ​​the powder through ball milling, thereby improving the activity of the powder. During the ball milling process, raw materials such as alumina or aluminum powder undergo nitriding or carbonization reduction reactions under the assistance of the ball mill to generate aluminum nitride powder.

[0003] However, during the ball milling process of raw materials such as alumina or aluminum powder, the raw material powder will experience two opposing forces: fracture and cold welding. These two forces occur simultaneously during the ball milling process and compete with each other. This may cause the powder particles to increase in size due to cold welding, forming agglomeration and resulting in uneven powder particle size. This, in turn, affects the nitriding or carburization reduction reaction of the raw material powder, thus reducing product quality. Summary of the Invention

[0004] The purpose of this invention is to provide an aluminum nitride powder preparation apparatus to solve at least one technical problem existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an aluminum nitride powder preparation device, comprising a base plate, two mounting brackets fixedly mounted on the top surface of the base plate, a rotating frame rotatably mounted between the two mounting brackets via a rotating shaft, mounting shafts rotatably mounted on two opposing inner walls inside the rotating frame, and a rotating ring inclinedly connected to one end of the two mounting shafts that are close to each other, the inner wall of the rotating ring rotatably mounted with a grinding barrel, and two interconnected grinding chambers being opened inside the grinding barrel, each grinding chamber containing a plurality of grinding media, the diameters of the grinding media in the two grinding chambers being different, and the inner diameter of the connection between the two grinding chambers being smaller than the diameter of the grinding media;

[0006] It also includes a drive assembly for driving the grinding barrel to rotate along its axis;

[0007] It also includes a switching component, which is used to switch the tilt angle of the grinding barrel so that the height positions of the two grinding chambers inside it are interchanged.

[0008] Preferably, the drive assembly includes two fixed frames respectively fixedly installed on the top surfaces of both sides of the base plate. Each of the two fixed frames has a sliding block installed inside, and each of the two sliding blocks has a rotating frame installed on it. A motor is fixedly installed inside the rotating frame. Fixed shafts are coaxially fixed at the center of both ends of the grinding barrel. The main shaft of the motor passes through the end of the rotating frame and is fixedly connected to the fixed shaft through a connecting part.

[0009] Preferably, the connecting part includes a connecting shaft fixedly installed at the end of the motor spindle, and a sliding tube is slidably connected to the outer wall of the connecting shaft by a flat key. The sliding tube is fixedly connected to the fixed shaft by a universal joint.

[0010] Preferably, the rotating frame sidewall is rotatably connected to a fixed sleeve sleeved on the outer wall of the sliding tube, universal joint and fixed shaft, and the inner wall of the fixed sleeve is slidably connected to the outer wall of the sliding tube by a flat key. An arc-shaped strip is fixedly installed at one end of the fixed sleeve near the grinding barrel. A sliding groove is opened in the arc-shaped strip. An electrically controlled slider that can slide in the sliding groove is rotatably installed on the outer wall of the fixed shaft. The arc-shaped strip and the sidewall of the fixed sleeve are together provided with a groove that allows the universal joint and fixed shaft to slide in or out.

[0011] Preferably, the switching component includes a transverse groove formed on the side wall of the sliding block, the side wall of the rotating frame is fixed with a rotating shaft that can rotate and slide within the transverse groove, and the sliding block is vertically rotatably mounted in the fixed frame and can be vertically adjusted up and down.

[0012] Preferably, a fixing plate is fixedly installed on the side wall of the fixing frame, and a rotating rod is rotatably installed on the outer wall of the fixing plate. A tension spring is provided between the end of the rotating rod away from the fixing plate and the sliding block. Two limiting pins that can restrict the rotation of the rotating rod are fixedly installed on the side wall of the fixing plate. A reciprocating lever is also rotatably installed on the side wall of the fixing plate. The lever is V-shaped, and pins are fixed at the ends of the two arms of the V-shape.

[0013] Preferably, a flow monitor is fixedly installed at the connection between the two grinding chambers, and the flow monitor is connected to the lever via an electrical signal.

[0014] Preferably, the rotating ring and the grinding barrel share an annular cooling chamber, and the cooling chamber in the rotating ring and the cooling chamber in the grinding barrel are sealed and rotatably connected at their joints. The cooling chambers are connected to the external liquid supply assembly through cooling channels in two mounting shafts to form a liquid supply circuit.

[0015] Preferably, one-way cooling pipes are fixedly installed on the outer walls of the two grinding chambers inside the grinding barrel, and the two ends of the one-way cooling pipes are respectively connected to the cooling chambers in one direction.

[0016] A process for preparing aluminum nitride powder using an aluminum nitride powder preparation apparatus includes the following steps:

[0017] Step 1: When using this device, first put alumina powder or aluminum powder into the grinding barrel, and then adjust the grinding barrel to an inclined state by switching components so that the alumina powder enters the grinding chamber on the side with larger grinding media.

[0018] Step 2: Then, the grinding barrel is driven to rotate along its axis by the drive component. The powder material in the grinding chamber is ball-milled by the friction between the larger grinding media and the grinding barrel, as well as the mutual collision between the grinding media, which quickly reduces the particle size and size of the powder material and reduces the grinding time.

[0019] Step 3: After the raw material powder has been ball-milled in the grinding chamber with a larger grinding medium for a preset time, the tilt angle of the grinding barrel is adjusted by switching components to switch the height positions of the two grinding chambers, so that the grinding chamber with a smaller grinding medium is at the lower end, and the raw material powder will flow into the grinding chamber with a smaller grinding medium under the action of gravity.

[0020] Step 4: Then, the grinding barrel is driven to rotate along its axis by the drive component. The raw material powder is ball-milled using a smaller grinding media. This further refines the raw material powder under the action of the smaller grinding media, enhances the surface activity of the powder particles, and removes it after completing the preset ball milling time. Then, under suitable conditions, the raw material powder is nitrided and calcined to finally obtain aluminum nitride powder.

[0021] Step 5: After replacing the raw material powder in the grinding chamber, repeat steps one to four above.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] I. This invention uses a switching component to drive the grinding barrel to tilt around its axial center, allowing the raw material powder to be ball-milled sequentially in two grinding chambers. This allows the raw material powder to rapidly reduce its particle size under the action of a larger grinding medium, thereby reducing the total ball-milling time and the occurrence of cold welding. Subsequently, the raw material powder is ball-milled with a smaller grinding medium at high precision, further refining the raw material powder while reducing the impact of cold welding on the ball-milling quality, thus improving the ball-milling quality of alumina powder and achieving the goal of improving the quality of aluminum nitride powder.

[0024] II. This invention drives the grinding barrel to rotate around a fixed axis at a lower position by an electrically controlled slider at a higher position, thus making the grinding barrel move in a conical shape. This allows for cleaning of the outer wall of the grinding media at a higher position without affecting the grinding work in the lower grinding chamber. In addition, by switching the height of the grinding chambers on both sides using a switching component, the grinding media on both sides can be cleaned during the ball milling of the raw material powder. The raw material powder adhering to the outer wall of the grinding media can enter the lower grinding chamber for further grinding through the central connection. This reduces the impact of cold welding on the ball milling quality and improves the utilization rate of raw materials. After the ball milling is completed, by driving the electrically controlled sliders on both sides to rotate the grinding barrel in a conical shape around the midpoint of the axis, the outer walls of the grinding media on both sides can be cleaned simultaneously, improving the cleaning effect of the grinding media.

[0025] Third, this invention cools the two grinding chambers at the connection point, eliminating the heat generated by ball milling and creating a low-temperature environment for the two grinding chambers. This not only reduces the powder hardness and increases the material brittleness, making the raw material powder easier to refine under the influence of ball milling and shortening the ball milling time, but also further eliminates the cold welding phenomenon through the low-temperature environment. By ball milling in a low-temperature environment and cleaning the outer wall of the grinding media, combined with the shortening of the ball milling time by the large-diameter grinding media, this invention can solve the problem of low quality aluminum nitride powder caused by poor ball milling quality in the traditional ball milling method. Attached Figure Description

[0026] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0027] Figure 2 This is a cross-sectional view of the three-dimensional structure of the present invention;

[0028] Figure 3 This is a side cross-sectional view of the present invention;

[0029] Figure 4 This is a three-dimensional structural diagram of the connecting part in this invention;

[0030] Figure 5 This is a three-dimensional cross-sectional view of the connecting part in this invention;

[0031] Figure 6 For the present invention Figure 3 A magnified view of a section at point A in the middle;

[0032] Figure 7 This is a diagram showing the state of the electrically controlled slider after it has slid in this invention.

[0033] Figure 8 This is a three-dimensional structural diagram of the unidirectional cooling pipe in this invention.

[0034] In the diagram: 1. Base plate; 2. Mounting bracket; 3. Rotating frame; 4. Grinding barrel; 5. Fixed shaft; 6. Fixed sleeve; 7. Arc strip; 8. Groove; 9. Sliding groove; 10. Electrically controlled slider; 11. Universal joint; 12. Sliding tube; 13. Mounting shaft; 14. Rotating ring; 15. Cooling chamber; 16. Flow monitor; 17. Fixed frame; 18. Sliding block; 19. Rotating frame; 20. Motor; 21. Fixed plate; 22. Rotating rod; 23. Tension spring; 24. Actuating rod; 25. Connecting shaft; 26. One-way cooling tube. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Please see Figures 1 to 8 The present invention provides a technical solution: an aluminum nitride powder preparation device, including a base plate 1, two mounting frames 2 are fixedly installed on the top surface of the base plate 1, a rotating frame 3 is rotatably installed between the two mounting frames 2 via a rotating shaft, two opposing inner walls inside the rotating frame 3 are rotatably installed with mounting shafts 13, the two mounting shafts 13 are fixedly connected at their close ends to an inclined rotating ring 14, a grinding barrel 4 is rotatably installed on the inner wall of the rotating ring 14, the grinding barrel 4 has two interconnected grinding chambers inside, the two grinding chambers contain a plurality of grinding media, and the diameters of the grinding media in the two grinding chambers are different, the inner diameter of the connection between the two grinding chambers is smaller than the diameter of the grinding media;

[0037] It also includes a drive assembly for driving the grinding barrel 4 to rotate along its axis;

[0038] It also includes a switching component, which is used to switch the tilt angle of the grinding barrel 4 so that the height positions of the two grinding chambers inside it are swapped.

[0039] In use, alumina powder or aluminum powder is first placed into the grinding barrel 4, and the grinding barrel 4 is adjusted to an inclined state by the switching component, so that the alumina powder enters the grinding chamber on the side with larger grinding media. Then, the driving component drives the grinding barrel 4 to rotate along its axis. The larger grinding media, which can be small balls made of aluminum nitride, ball-mills the powder material in the grinding chamber using friction and mutual collisions between the grinding media, quickly reducing the particle size and size of the powder material and shortening the grinding time. After the raw material powder has been ball-milled in the grinding chamber with larger grinding media for the preset time, By adjusting the tilt angle of the grinding barrel 4 using the switching component, the height positions of the two grinding chambers are switched. Even if the grinding chamber with smaller grinding media is at the lowest end, the raw material powder can enter the grinding chamber with smaller grinding media. Then, the grinding barrel 4 is driven to rotate along its axis by the drive component, and the raw material powder is ball-milled using smaller grinding media. This further refines the raw material powder under the action of smaller grinding media, enhances the surface activity of the powder particles, and removes it after completing the preset ball milling time. Then, under suitable conditions, the subsequent nitriding and calcination are completed to complete the preparation of aluminum nitride powder.

[0040] In this way, by switching components to drive the grinding barrel 4 to adjust its tilt around its axial center, the raw material powder can be ball-milled sequentially in two grinding chambers. This allows the raw material powder to rapidly reduce its particle size under the action of larger grinding media, thereby reducing the total ball milling time and the occurrence of cold welding. Subsequently, the raw material powder is ball-milled with smaller grinding media at high precision, which further refines the raw material powder while reducing the impact of cold welding on the ball milling quality and reducing agglomeration. Moreover, the graded ball milling can use ball milling media of different sizes to treat particles of different sizes more effectively, reducing agglomeration caused by particle size differences, thereby obtaining a more uniform powder material and improving the ball milling quality of alumina powder, thus achieving the goal of improving the quality of aluminum nitride powder.

[0041] Furthermore, the drive assembly includes two fixed frames 17 respectively fixedly installed on the top surfaces of the two sides of the base plate 1. Each fixed frame 17 is equipped with a sliding block 18, and each sliding block 18 is equipped with a rotating frame 19. A motor 20 is fixedly installed inside the rotating frame 19. Fixed shafts 5 are coaxially fixed at the center of both ends of the grinding barrel 4. The main shaft of the motor 20 passes through the end of the rotating frame 19 and is fixedly connected to the fixed shaft 5 through a connecting part.

[0042] A specific implementation of the driver component is provided based on the above embodiments. See details below. Figure 2When the motor 20 drives the fixed shaft 5 to rotate, the fixed shaft 5 drives the grinding barrel 4 to rotate together, thus achieving the purpose of driving the grinding barrel 4 to rotate along the axis mentioned above. Since the grinding barrel 4 and the rotating ring 14 are rotatably connected, and the rotating frame 3 can rotate around the mounting shaft 13, the motor 20 can still drive the fixed shaft 5 to rotate when the tilt angle of the grinding barrel 4 changes, providing a rotational basis for the subsequent second-stage grinding.

[0043] Furthermore, the connecting part includes a connecting shaft 25 fixedly installed at the end of the main shaft of the motor 20. A sliding tube 12 is slidably connected to the outer wall of the connecting shaft 25 via a flat key. The sliding tube 12 is fixedly connected to the fixed shaft 5 via a universal joint 11.

[0044] According to the above embodiments, a specific embodiment of the connecting part is provided. When the motor 20 drives the connecting shaft 25 to rotate together, the connecting shaft 25 drives the sliding tube 12 and the universal shaft 11 to rotate together through the spline, and drives the fixed shaft 5 to rotate, thereby completing the transmission between the motor 20 and the fixed shaft 5.

[0045] Furthermore, a fixed sleeve 6 is rotatably connected to the side wall of the rotating frame 19 and is sleeved on the outer wall of the sliding tube 12, the universal shaft 11 and the fixed shaft 5. The inner wall of the fixed sleeve 6 is slidably connected to the outer wall of the sliding tube 12 by a flat key. An arc-shaped strip 7 is fixedly installed at one end of the fixed sleeve 6 near the grinding barrel 4. A sliding groove 9 is opened in the arc-shaped strip 7. An electrically controlled slider 10 that can slide in the sliding groove 9 is rotatably installed on the outer wall of the fixed shaft 5. The arc-shaped strip 7 and the side wall of the fixed sleeve 6 are together provided with a groove 8 that allows the universal shaft 11 and the fixed shaft 5 to slide in or out.

[0046] As can be seen from the above implementation method, when one side of the electrically controlled slider 10 slides within the sliding groove 9, see [specific details]. Figure 3 At this time, the axis of the grinding barrel 4 rotates counterclockwise around the lower left as the center. Figure 7 As shown, at this time, by driving the left motor 20, the grinding barrel 4 can be driven to rotate in a conical shape around the left fixed shaft 5. Even if the right end of the grinding barrel 4 moves in a circular motion around its axis, since the mounting shaft 13 is rotatably connected to the rotating frame 3, and the rotating frame 3 can rotate around the connecting shaft 25 between itself and the mounting bracket 2, the mounting shaft 13 can still provide support for the grinding barrel 4 when it rotates in a conical shape. The grinding barrel 4 also switches from self-rotation to self-rotation and revolution. At this time, the grinding media in the right grinding chamber of the grinding barrel 4 will shake in the grinding chamber under the drive of the grinding barrel 4, and the powder adhering to the outer wall of the grinding media will be shaken off by the vibration through the collision between them. This avoids the outer wall of the grinding media adhering to the raw material powder adhering to it from adsorbing each other under the action of cold welding to form large particles of powder, which would reduce the grinding quality. When the electric control sliders 10 on both sides slide along their respective sliding grooves 9 at the same time, the fixed shafts 5 on both sides will deflect at the same time. See the details. Figure 7 At this time, the drive motor 20 can drive the left and right sides of the grinding barrel 4 to rotate in a cone shape with the midpoint of its axis as the center. This allows the grinding media in both grinding chambers to shake off the powder material on their outer walls under the action of vibration, thus cleaning the outer walls of the grinding media on both sides at the same time. This further eliminates the influence of cold welding on the ball milling quality and also further reduces the agglomeration of powder.

[0047] In this way, by driving the electrically controlled slider 10 at the higher position to rotate the grinding barrel 4 around the fixed shaft 5 at the lower position, the grinding barrel 4 can move in a conical shape. This allows the grinding work in the lower grinding chamber to be cleaned while the outer wall of the grinding media at the higher position is cleaned. In addition, by switching the height position of the grinding chambers on both sides with the switching component, the grinding media on both sides can be cleaned during the ball milling of the raw material powder. The raw material powder adhering to the outer wall of the grinding media can enter the grinding chamber at the lower position for further grinding through the connecting part in the middle. This reduces the impact of cold welding on the ball milling quality and improves the utilization rate of raw materials. After the ball milling is completed, by driving the electrically controlled sliders 10 on both sides to drive the grinding barrel 4 to rotate in a conical shape around the midpoint of the axis, the outer walls of the grinding media on both sides can be cleaned at the same time, improving the cleaning effect of the grinding media.

[0048] It is worth mentioning that during the rotation of the grinding barrel 4, the electrically controlled slider 10 switches back and forth between sliding on one side and sliding on both sides, which can continuously clean the outer wall of the grinding media during the grinding process. This can minimize the cold welding phenomenon caused by the adhesion of raw material powder, further improve the ball milling quality, and thus improve the final quality of aluminum nitride powder.

[0049] Furthermore, the switching component includes a transverse groove formed on the side wall of the sliding block 18, and a rotating shaft that can rotate and slide within the transverse groove is fixed to the side wall of the rotating frame 19. The sliding block 18 is vertically rotatably mounted in the fixed frame 17 and can be vertically adjusted up and down.

[0050] As can be seen from the above embodiments, when the sliding block 18 slides along the fixed frame 17, the distance between the sliding block 18 and the grinding barrel 4 is shortened, as detailed in the following figure. Figure 3 At this time, the rotating frame 19 slides along the side wall of the sliding block 18, which ensures that the axis of the grinding barrel 4 does not deflect when the sliding block 18 slides. When the left sliding block 18 slides upward, it drives the right sliding block 18 to slide downward, so that the left grinding chamber rises to a high position while the right grinding chamber falls to a low position, thus completing the switching of the height position of the two grinding chambers.

[0051] Furthermore, a fixing plate 21 is fixedly installed on the side wall of the fixing frame 17, and a rotating rod 22 is rotatably installed on the outer wall of the fixing plate 21. A tension spring 23 is provided between the end of the rotating rod 22 away from the fixing plate 21 and the sliding block 18. Two limiting pins that can restrict the rotation of the rotating rod 22 are fixedly installed on the side wall of the fixing plate 21. A reciprocating swinging lever 24 is also rotatably installed on the side wall of the fixing plate 21. The lever 24 is V-shaped, and pins are fixed at the ends of the two arms of the V-shape.

[0052] As can be seen from the above embodiments, the actuating rod 24 is a V-shaped connecting rod composed of two connecting rods, and both ends are provided with pins. When the external driving structure drives the actuating rod 24 to swing back and forth, the pin on one of the arms of the actuating rod 24 will actuate the rotating rod 22 to swing. When the rotating rod 22 swings, it can pull the sliding block 18 to slide along the fixed frame 17 through the tension spring 23. In this way, the swing of the actuating rods 24 on both sides can drive the sliding blocks 18 on both sides to switch their up and down positions, thereby switching the tilt direction of the grinding barrel 4, and thus achieving the purpose of switching the grinding chamber.

[0053] It is worth noting that the rotation angle of the rotating rod 22 when the actuating lever 24 rotates via the pin is insufficient to make the rotating rod 22 cross the line with the connection point of the tension spring 23 and the sliding block 18. That is, after the actuating lever 24 returns to its original position, the rotating rod 22, having lost the support of the pin, will, under the weight of the weight inside the lower grinding chamber, cause the sliding block 18 to move down and return to its original position, pulling the tension spring 23 to return the rotating rod 22 to its original position. However, during this process, when the sliding block 18 moves up under the action of the tension spring 23, it will cause the grinding barrel 4 to cross the horizontal state. This will cause the grinding chamber, which was originally in a lower position, to briefly switch to a higher position, and the raw material powder inside will move towards... In another grinding chamber, as the sliding block 18 moves down and resets under the action of gravity in the corresponding grinding chamber and the tension of the tension spring 23, if the flow of the raw material powder causes the gravity in the other grinding chamber to be greater than that in the first grinding chamber, that is, if the gravity in the other grinding chamber is sufficient to overcome the tension of the tension spring 23, the grinding barrel 4 will tilt and switch instead of resetting. This means that the grinding degree of the raw material powder in the first grinding chamber (i.e., the grinding chamber with a large-diameter grinding medium) has met the standard. After the initial grinding, the particle size and flowability of the raw material powder meet the requirements for subsequent secondary grinding. Therefore, the grinding chamber switches at this time.

[0054] Conversely, when the amount of powder flowing into the original high grinding chamber is insufficient, that is, when the gravity in the other grinding chamber is sufficient to overcome the tension of the side spring 23, the grinding barrel 4 will reset, and the powder material in the other grinding chamber will flow back into the lower grinding chamber to continue grinding.

[0055] In this way, the switching between grinding chambers can be automatically controlled by utilizing the changes in the raw material powder during the grinding process, so as to achieve the effect of real-time switching according to the degree of grinding, and further improve the preparation effect of raw material powder.

[0056] It is worth mentioning that since the sliding block 18 is limited only by the tension spring 23 and the rotating rod 22, when the grinding barrel 4 makes a conical motion with its lower fixed shaft 5 as the center, that is, when cleaning the outer wall of the grinding medium at the higher position, the sliding block 18 at the higher position swings up and down continuously under the action of the centrifugal force of the rotation of the grinding barrel 4. This provides the contraction and extension of the tension spring 23 to eliminate the vibration generated when the grinding barrel 4 rotates, and avoids misalignment or other effects caused by vibration after long-term use of the device.

[0057] Furthermore, a flow monitor 16 is fixedly installed at the connection between the two grinding chambers, and the flow monitor 16 is connected to the toggle lever 24 via an electrical signal.

[0058] As can be seen from the above embodiments, by using the flow monitor 16 at the connection of the two grinding chambers, the sensitivity of the device to the powder grinding effect is improved. After the grinding effect of the grinding media on one side reaches the standard, the toggle lever 24 is driven to switch the height position of the two grinding chambers, and the grinding media on the other side is used to perform two-stage grinding of the powder. In conjunction with cleaning the outer wall of the grinding media, the agglomeration effect of cold welding on the powder is ensured to be far lower than the crushing effect of ball milling, thereby improving the quality of ball milling.

[0059] In this embodiment, compared to the above embodiment, the initial swing amplitude of the lever 24 is still the same. When the flow monitor 16 detects that the grinding effect of the powder meets the standard, it will control the lever 24 to increase the swing amplitude, thereby completing the switching of the grinding chamber by the tossing method, rather than by the gravity of the grinding chamber, which can further improve the sensitivity of the device.

[0060] Furthermore, the rotating ring 14 and the grinding barrel 4 are provided with an annular cooling chamber 15, and the cooling chamber 15 in the rotating ring 14 and the cooling chamber 15 in the grinding barrel 4 are sealed and rotatably connected at the joint. The cooling chamber 15 forms a liquid supply circuit with the external liquid supply assembly through the cooling channels in the two mounting shafts 13.

[0061] As can be seen from the above implementation method, by introducing liquid nitrogen into the cooling circuit composed of the cooling channel and cooling chamber 15 in the mounting shaft 13 through the external liquid supply component, a cooling effect can be provided from the center of the grinding barrel 4 to the grinding chambers on both sides, so that the raw material powder can be ground in a low temperature environment. While reducing the hardness of the raw material and increasing its brittleness, the low temperature environment further eliminates the cold welding phenomenon.

[0062] In this way, by cooling the two grinding chambers at the connection point, the heat generated by ball milling is eliminated while creating a low-temperature environment for the two grinding chambers. This not only reduces the powder hardness and increases the brittleness of the material, making the raw material powder easier to refine under the influence of ball milling and shortening the ball milling time, but also further eliminates the cold welding phenomenon through the low-temperature environment. By ball milling in a low-temperature environment and cleaning the outer wall of the grinding media, combined with the shortening of the ball milling time by large-diameter grinding media, the pain point of poor ball milling quality leading to low quality of aluminum nitride powder in the traditional ball milling method can be solved.

[0063] Furthermore, one-way cooling pipes 26 are fixedly installed on the outer walls of the two grinding chambers inside the grinding barrel 4, and the two ends of the one-way cooling pipes 26 are unidirectionally connected to the cooling chamber 15 respectively.

[0064] As can be seen from the above implementation method, when the external liquid supply component introduces liquid nitrogen into the cooling circuit formed by the cooling channel and the cooling chamber 15 in the mounting shaft 13, the liquid nitrogen enters the one-way cooling pipe 26, circles around the outer wall of the grinding chamber on both sides, and then returns to the cooling chamber 15 and circulates through the external liquid supply component, further improving the cooling effect on the grinding chamber, thereby eliminating the influence of cold welding on the ball milling quality.

[0065] A process for preparing aluminum nitride powder using an aluminum nitride powder preparation apparatus includes the following steps:

[0066] Step 1: When using this device, first put alumina powder or aluminum powder into the grinding barrel 4, and adjust the grinding barrel 4 to an inclined state by switching components so that the alumina powder enters the grinding chamber on the side with larger grinding media.

[0067] Step 2: Then, the grinding barrel 4 is driven to rotate along its axis by the drive component. The powder material in the grinding chamber is ball-milled by the friction between the larger grinding media and the grinding barrel 4 and the mutual collision between the grinding media, which quickly reduces the particle size and size of the powder material and reduces the grinding time.

[0068] Step 3: After the raw material powder has been ball-milled in the grinding chamber with a larger grinding medium for a preset time, the tilt angle of the grinding barrel 4 is adjusted by switching the component to switch the height positions of the two grinding chambers. Even if the grinding chamber with a smaller grinding medium is at the lowest end, the raw material powder can enter the grinding chamber with a smaller grinding medium.

[0069] Step 4: Then, the grinding barrel 4 is driven to rotate along its axis by the drive component. The raw material powder is ball-milled using a smaller grinding medium, which further refines the raw material powder under the action of the smaller grinding medium, enhances the surface activity of the powder particles, and removes it after completing the preset ball milling time. Then, the raw material powder is nitrided and calcined under suitable conditions.

[0070] Step 5: After replacing the raw material powder in the grinding chamber, repeat steps one to four above.

[0071] The standard parts used in this embodiment can be purchased directly from the market, while the non-standard structural parts described in the specification and drawings can be processed directly based on existing technical knowledge without any doubt. At the same time, the connection methods of each component adopt mature conventional methods in the existing technology, and the machinery, parts and equipment all adopt conventional models in the existing technology, so they will not be described in detail here.

[0072] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An apparatus for preparing aluminum nitride powder, comprising a base plate (1), characterized in that: Two mounting brackets (2) are fixedly installed on the top surface of the base plate (1). A rotating frame (3) is rotatably installed between the two mounting brackets (2) via a rotating shaft. Mounting shafts (13) are rotatably installed on the two opposing inner walls inside the rotating frame (3). A rotating ring (14) is fixedly connected to one end of the two mounting shafts (13) that are close to each other. A grinding barrel (4) is rotatably installed on the inner wall of the rotating ring (14). Two interconnected grinding chambers are opened inside the grinding barrel (4). Several grinding media are provided in the two grinding chambers. The diameters of the grinding media in the two grinding chambers are different. The inner diameter of the connection between the two grinding chambers is smaller than the diameter of the grinding media. It also includes a drive assembly for driving the grinding barrel (4) to rotate along its axis; It also includes a switching component, which is used to switch the tilt angle of the grinding barrel (4) so ​​that the height positions of the two grinding chambers inside it are interchanged; The drive assembly includes two fixed frames (17) respectively fixedly installed on the top surfaces of the two sides of the base plate (1). Each of the two fixed frames (17) is equipped with a sliding block (18). Each of the two sliding blocks (18) is equipped with a rotating frame (19). A motor (20) is fixedly installed in the rotating frame (19). Fixed shafts (5) are coaxially fixed at the center of both ends of the grinding barrel (4). The main shaft of the motor (20) passes through the end of the rotating frame (19) and is fixedly connected to the fixed shaft (5) through a connecting part. The connecting part includes a connecting shaft (25) fixedly installed at the end of the motor (20) spindle. A sliding tube (12) is slidably connected to the outer wall of the connecting shaft (25) by a flat key. The sliding tube (12) is fixedly connected to the fixed shaft (5) by a universal joint (11). The rotating frame (19) has a fixed sleeve (6) rotatably connected to the side wall of the rotating frame (19), which is sleeved on the outer wall of the sliding tube (12), the universal shaft (11) and the fixed shaft (5). The inner wall of the fixed sleeve (6) is slidably connected to the outer wall of the sliding tube (12) by a flat key. An arc-shaped strip (7) is fixedly installed at one end of the fixed sleeve (6) near the grinding barrel (4). A sliding groove (9) is opened in the arc-shaped strip (7). An electrically controlled slider (10) that can slide in the sliding groove (9) is rotatably installed on the outer wall of the fixed shaft (5). The arc-shaped strip (7) and the side wall of the fixed sleeve (6) are together provided with a groove (8) that allows the universal shaft (11) and the fixed shaft (5) to slide in or out. The switching assembly includes a transverse groove formed on the side wall of the sliding block (18), and the side wall of the rotating frame (19) is fixed with a rotating shaft that can rotate and slide in the transverse groove. The sliding block (18) is vertically rotatably installed in the fixed frame (17) and can be vertically adjusted up and down. A fixing plate (21) is fixedly installed on the side wall of the fixing frame (17). A rotating rod (22) is rotatably installed on the outer wall of the fixing plate (21). A tension spring (23) is provided between the end of the rotating rod (22) away from the fixing plate (21) and the sliding block (18). Two limiting pins that can limit the rotation of the rotating rod (22) are fixedly installed on the side wall of the fixing plate (21). A reciprocating swinging lever (24) is also rotatably installed on the side wall of the fixing plate (21). The lever (24) is V-shaped, and pins are fixed at the ends of the two arms of the V-shape. A flow monitor (16) is fixedly installed at the connection between the two grinding chambers, and the flow monitor (16) is connected to the lever (24) by an electrical signal.

2. The aluminum nitride powder preparation apparatus according to claim 1, characterized in that: The rotating ring (14) and the grinding barrel (4) are provided with an annular cooling chamber (15), and the cooling chamber (15) in the rotating ring (14) and the cooling chamber (15) in the grinding barrel (4) are sealed and rotatably connected at the joint. The cooling chamber (15) is connected to the external liquid supply assembly through the cooling channels in the two mounting shafts (13) to form a liquid supply circuit.

3. The aluminum nitride powder preparation apparatus according to claim 2, characterized in that: One-way cooling pipes (26) are fixedly installed on the outer walls of the two grinding chambers inside the grinding barrel (4), and the two ends of the one-way cooling pipes (26) are respectively connected to the cooling chamber (15) in one direction.

4. A preparation process for preparing aluminum nitride powder using the aluminum nitride powder preparation apparatus according to claim 1, characterized in that, The preparation process includes the following steps: Step 1: First, put alumina powder or aluminum powder into the grinding barrel (4), and adjust the grinding barrel (4) to an inclined state by switching components so that the alumina powder enters the grinding chamber on the side with larger grinding media. Step 2: Then, the grinding barrel (4) is driven to rotate along its axis by the drive component. The powder material in the grinding chamber is ball-milled by the friction between the larger grinding media and the grinding barrel (4) and the mutual collision between the grinding media, which quickly reduces the particle size and size of the powder material and reduces the grinding time. Step 3: After the raw material powder has been ball-milled in the grinding chamber with a larger grinding medium for a preset time, the tilt angle of the grinding barrel (4) is adjusted by switching components to switch the height positions of the two grinding chambers so that the grinding chamber with a smaller grinding medium is at the lower end. The raw material powder will flow into the grinding chamber with a smaller grinding medium under the action of gravity. Step 4: Then continue to drive the grinding barrel (4) to rotate along its axis by the drive component, and use a smaller grinding medium to ball mill the raw material powder, so that the raw material powder is further refined under the action of a smaller grinding medium, enhancing the surface activity of the powder particles, and after completing the preset ball milling time, it is taken out, and the subsequent nitriding and calcination of the raw material powder are completed under suitable conditions, and finally aluminum nitride powder is obtained. Step 5: After replacing the raw material powder in the grinding chamber, repeat steps one to four above.

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