Temperature control air inlet device and preparation method of aluminum nitride powder

Abstract

The invention discloses a preparation method of aluminum nitride powder. The method comprises the following steps: introducing nitrogen into a muffle furnace filled with aluminum oxide powder and carbon powder by using a temperature control gas inlet device; the invention further discloses a temperature control air inlet device, the temperature control air inlet device comprises a first air guide pipe, a first air guide plate, a second air guide pipe, a second air guide plate and an air inlet pipe, holes are formed in the air guide plates, pipe openings are connected with corresponding hole openings according to the sequence, the first air guide plate is embedded into the side wall of the furnace body, the first air guide pipe enters the furnace body through the furnace wall, and the second air guide pipe enters the air inlet pipe through the second air guide plate. The second gas guide pipe and the second gas guide plate are both located in the preheating atmosphere. The temperature control gas inlet device is not provided with through holes, and when parameters such as the staggering rate of the holes, the hole area proportion, the length of the gas guide pipe, the shape and the size of the gas guide pipe and the like are limited to be in a proper range, gas can be rapidly preheated and is prevented from blowing away powder to be reacted in the furnace body, so that the yield and the efficiency of aluminum nitride reaction are improved.

Description

Technical Field

[0001] The invention relates to a temperature-controlled air intake device, and in particular to a method for preparing aluminum nitride powder by dispersing and introducing nitrogen into a muffle furnace using the temperature-controlled air intake device. Background Art

[0002] In the field of material preparation technology, especially in the preparation process of aluminum nitride powder, carbon thermal reduction is a commonly used method. This method mainly involves a reduction reaction between carbon powder and aluminum oxide under high temperature conditions, and then reacts with nitrogen to generate aluminum nitride powder. In the traditional carbon thermal reduction method, a carbon thermal reduction furnace is required to introduce nitrogen into the furnace body through a pipeline. Among them, nitrogen is not only a commonly used protective gas to prevent oxidation during the reaction process, but also a reaction gas, which reacts with aluminum oxide and carbon powder to generate aluminum nitride.

[0003] In the existing technology, nitrogen is usually directly introduced into the furnace body of the muffle furnace through a pipeline. The advantage of this method is that it is simple to operate and has low equipment cost. However, the disadvantages of this method are also obvious. First, due to the initial pressure difference, the gas flow rate is too fast, which can easily blow away the powder, resulting in a decrease in yield. Secondly, the room temperature gas has a small contact area in the pipeline and a short preheating time, which causes the gas to fail to reach the temperature required for the reaction, affecting the efficiency of the reaction.

[0004] It is urgent to discover a new type of temperature-controlled air intake device to solve the problems existing in the existing technology. Summary of the invention

[0005] A first aspect of the present invention provides a method for preparing aluminum nitride powder, comprising a step of using a temperature-controlled air inlet device to introduce nitrogen into a muffle furnace containing aluminum oxide powder and carbon powder, wherein the temperature-controlled air inlet device comprises an air guide plate, wherein the air guide plate is a hollow plate, wherein the vertical projection area of ​​the air guide plate is a parallelogram, wherein the directions of two adjacent sides of the parallelogram are respectively recorded as a first direction and a second direction, wherein the side lengths of the parallelogram in the first direction and the second direction are L1 and L2 respectively, wherein the angle between the first direction and the second direction is θ, and the area of ​​the parallelogram is as follows:

[0006] S = L1*L2*sinθ;

[0007] The air guide plate is divided into a first air guide plate and a second air guide plate;

[0008] The two largest opposite surfaces of the first air guide plate are respectively denoted as F11 and F12, the F11 includes a plurality of first small holes, the plurality of the first small holes form a first small hole group, the F12 includes a plurality of second small holes, the plurality of the second small holes form a second small hole group;

[0009] On the F11, a plurality of the first small holes form a first part, the first small holes of the first part extend in the first direction and are evenly spaced, a plurality of the first small holes form a second part, the first small holes of the second part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the first small holes of the first part is equal to the spacing between the centers of the first small holes of the second part, and the spacing distance in the first direction is X F11 The first small hole group is composed of a plurality of the first parts and the second parts, the first parts and the second parts are spaced equally from each other, and the spacing distance in the second direction is Y F11 ;

[0010] On the F12, a plurality of the second small holes form a third part, the second small holes of the third part extend in the first direction and are evenly spaced, a plurality of the second small holes form a fourth part, the second small holes of the fourth part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the second small holes of the third part is equal to the spacing between the centers of the second small holes of the fourth part, and the spacing distance in the first direction is X F12 The second small hole group is composed of a plurality of the third part and the fourth part, the third part and the fourth part are equally spaced from each other, and the spacing distance in the second direction is Y F12 ;

[0011] The projection O11 of the center of the first small hole on the F12 does not overlap with the center of the second small hole O12, and the straight-line distance between O11 and O12 is denoted as d1;

[0012] The two largest opposite surfaces of the second air guide plate are respectively denoted as F21 and F22, the F21 comprises a plurality of third small holes, the plurality of third small holes constitute a third small hole group, and the F22 comprises only one large hole in the center;

[0013] On the F21, a plurality of the third small holes form a fifth part, the third small holes of the fifth part extend in the first direction and are evenly spaced, a plurality of the third small holes form a sixth part, the third small holes of the sixth part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the third small holes of the fifth part is equal to the spacing between the centers of the third small holes of the sixth part, and the spacing distance in the first direction is X F21 The third group of small holes is composed of a plurality of the fifth part and the sixth part, the fifth part and the sixth part are equally spaced from each other, and the spacing distance in the second direction is Y F21 ;

[0014] The projection of the third small hole on F12 coincides with the second small hole;

[0015] The total area of ​​the first small holes is defined as S11, the total area of ​​the second small holes is defined as S12, and the total area of ​​the third small holes is defined as S21. The ratios of S11, S12, S21 to the area of ​​the parallelogram S are R11=S11 / S, R12=S12 / S, and R21=S21 / S, respectively. The area of ​​the large holes is defined as S22, and the ratio of S22 to the area of ​​the parallelogram S is R22=S22 / S.

[0016] The first air guide plate and the second air guide plate are parallel to each other, and the distance between the first air guide plate and the second air guide plate is denoted as h;

[0017] The temperature-controlled air intake device further includes an air duct, which is divided into a first air duct and a second air duct. The length of the first air duct is denoted as a1, and the length of the second air duct is denoted as a2, and a2 is equal to h.

[0018] The projection of the inner wall of the first airway tube on F11 completely coincides with the first small hole, the projection of the inner wall of the second airway tube on F12 completely coincides with the second small hole, and the projection of the inner wall of the second airway tube on F21 completely coincides with the third small hole;

[0019] The temperature-controlled air intake device further comprises an air intake pipe, the projection of the inner wall of the air intake pipe on the F22 completely coincides with the large hole;

[0020] The temperature-controlled air intake device also includes a temperature control device, which is filled with a preheated atmosphere;

[0021] The temperature-controlled air intake device is composed of a first air guide pipe, a first air guide plate, a second air guide pipe, a second air guide plate, and an air intake pipe from left to right, and each pipe opening is connected to a corresponding orifice in this order; the first air guide plate is embedded in the side wall of the furnace body, the first air guide pipe enters the furnace body through the furnace wall, and the second air guide pipe and the second air guide plate are both in a preheating atmosphere.

[0022] A second aspect of the present invention provides a temperature-controlled air intake device, the temperature-controlled air intake device comprising an air guide plate, the air guide plate being a hollow plate, the vertical projection area of ​​the air guide plate being a parallelogram, the directions of two adjacent sides of the parallelogram being respectively recorded as a first direction and a second direction, the side lengths of the parallelogram in the first direction and the second direction being respectively L1 and L2, the angle between the first direction and the second direction being θ, and the area of ​​the parallelogram being as follows:

[0023] S = L1*L2*sinθ;

[0024] The air guide plate is divided into a first air guide plate and a second air guide plate;

[0025] The two largest opposite surfaces of the first air guide plate are respectively denoted as F11 and F12, the F11 includes a plurality of first small holes, the plurality of the first small holes form a first small hole group, the F12 includes a plurality of second small holes, the plurality of the second small holes form a second small hole group;

[0026] On the F11, a plurality of the first small holes form a first part, the first small holes of the first part extend in the first direction and are evenly spaced, a plurality of the first small holes form a second part, the first small holes of the second part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the first small holes of the first part is equal to the spacing between the centers of the first small holes of the second part, and the spacing distance in the first direction is X F11 The first small hole group is composed of a plurality of the first parts and the second parts, the first parts and the second parts are spaced equally from each other, and the spacing distance in the second direction is Y F11 ;

[0027] On the F12, a plurality of the second small holes form a third part, the second small holes of the third part extend in the first direction and are evenly spaced, a plurality of the second small holes form a fourth part, the second small holes of the fourth part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the second small holes of the third part is equal to the spacing between the centers of the second small holes of the fourth part, and the spacing distance in the first direction is X F12 The second small hole group is composed of a plurality of the third part and the fourth part, the third part and the fourth part are equally spaced from each other, and the spacing distance in the second direction is Y F12 ;

[0028] The projection O11 of the center of the first small hole on the F12 does not overlap with the center of the second small hole O12, and the straight-line distance between O11 and O12 is denoted as d1;

[0029] The two largest opposite surfaces of the second air guide plate are respectively denoted as F21 and F22, the F21 comprises a plurality of third small holes, the plurality of third small holes constitute a third small hole group, and the F22 comprises only one large hole in the center;

[0030] On the F21, a plurality of the third small holes form a fifth part, the third small holes of the fifth part extend in the first direction and are evenly spaced, a plurality of the third small holes form a sixth part, the third small holes of the sixth part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the third small holes of the fifth part is equal to the spacing between the centers of the third small holes of the sixth part, and the spacing distance in the first direction is X F21 The third group of small holes is composed of a plurality of the fifth part and the sixth part, the fifth part and the sixth part are equally spaced from each other, and the spacing distance in the second direction is Y F21 ;

[0031] The projection of the third small hole on F12 coincides with the second small hole;

[0032] The total area of ​​the first small holes is defined as S11, the total area of ​​the second small holes is defined as S12, and the total area of ​​the third small holes is defined as S21. The ratios of S11, S12, S21 to the area of ​​the parallelogram S are R11=S11 / S, R12=S12 / S, and R21=S21 / S, respectively. The area of ​​the large holes is defined as S22, and the ratio of S22 to the area of ​​the parallelogram S is R22=S22 / S.

[0033] The first air guide plate and the second air guide plate are parallel to each other, and the distance between the first air guide plate and the second air guide plate is denoted as h;

[0034] The temperature-controlled air intake device further includes an air duct, which is divided into a first air duct and a second air duct. The length of the first air duct is denoted as a1, and the length of the second air duct is denoted as a2, and a2 is equal to h.

[0035] The projection of the inner wall of the first airway tube on F11 completely coincides with the first small hole, the projection of the inner wall of the second airway tube on F12 completely coincides with the second small hole, and the projection of the inner wall of the second airway tube on F21 completely coincides with the third small hole;

[0036] The temperature-controlled air intake device further comprises an air intake pipe, the projection of the inner wall of the air intake pipe on the F22 completely coincides with the large hole;

[0037] The temperature-controlled air intake device also includes a temperature control device, which is filled with a preheated atmosphere;

[0038] The temperature-controlled air intake device is composed of a first air guide pipe, a first air guide plate, a second air guide pipe, a second air guide plate, and an air intake pipe from left to right, and each pipe opening is connected to a corresponding orifice in this order; the first air guide plate is embedded in the side wall of the furnace body, the first air guide pipe enters the furnace body through the furnace wall, and the second air guide pipe and the second air guide plate are both in a preheating atmosphere.

[0039] Furthermore, the X F11 The ratio to L1 is 0.1 to 0.15;

[0040] Preferably 0.1 to 0.12;

[0041] The Y F11 The ratio to L2 is 0.1 to 0.15;

[0042] Preferably 0.1 to 0.12;

[0043] The X F12 The ratio to L1 is 0.1 to 0.15;

[0044] Preferably 0.1 to 0.12;

[0045] The Y F12 The ratio to L2 is 0.1 to 0.15;

[0046] Preferably 0.1 to 0.12;

[0047] The X F21 The ratio to L1 is 0.1 to 0.15;

[0048] Preferably 0.1 to 0.12;

[0049] The Y F21 The ratio to L2 is 0.1 to 0.15;

[0050] Preferably 0.1 to 0.12;

[0051] Furthermore, the value range of d1 is 40 to 200 mm;

[0052] Preferably 100 to 120 mm;

[0053] Furthermore, the value range of R11 is 0.7 to 0.9;

[0054] Preferably 0.8 to 0.9;

[0055] The value range of R12 is 0.5 to 0.7;

[0056] Preferably 0.6 to 0.7;

[0057] The value range of R21 is 0.5 to 0.7;

[0058] Preferably 0.6 to 0.7;

[0059] The value range of R22 is 0.3 to 0.7;

[0060] Preferably 0.4 to 0.6;

[0061] Furthermore, the value range of h is 10 to 100 mm;

[0062] Preferably 30 to 80 mm;

[0063] Furthermore, the value range of a1 is 50 to 100 mm;

[0064] Preferably 80 to 100 mm;

[0065] The value range of a2 is 10 to 100 mm;

[0066] Preferably 30 to 80 mm;

[0067] Further, the thickness of the first air guide plate ranges from 10 to 100 mm;

[0068] Preferably 50 to 60 mm;

[0069] The thickness of the second air guide plate ranges from 10 to 100 mm;

[0070] Preferably 50 to 60 mm;

[0071] Further, the projection shape of the first small hole, the second small hole, the third small hole, the large hole or the air guide tube on the air guide plate includes one or more combinations of triangle, parallelogram, pentagon, hexagon and circle;

[0072] Preferably, the projection shape is circular;

[0073] Furthermore, the diameter of the circular projection shape of the first airway tube ranges from 5 to 20 mm;

[0074] Preferably 10 to 20 mm;

[0075] The diameter of the circular projection shape of the second air guide tube ranges from 20 to 50 mm;

[0076] Preferably 20 to 30 mm;

[0077] Beneficial effects:

[0078] (1) The present invention provides a method for preparing aluminum nitride powder. In the preparation method, nitrogen can be dispersed and introduced into a muffle furnace to avoid blowing away the powder in the muffle furnace, thereby improving the yield of the aluminum nitride powder.

[0079] (2) The present invention proposes a temperature-controlled heating device, which can not only disperse nitrogen into the muffle furnace, but also preheat the gas, eliminate the temperature difference between the furnace body and the introduced nitrogen, and improve the reaction efficiency and yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0081] Figure 1 A three-dimensional diagram of a temperature-controlled air intake device (excluding a temperature-controlled device) according to a preferred embodiment of the present invention is exemplarily shown.

[0082] Figure 2 yes Figure 1 A view of the xz plane of the temperature control air intake device shown in ;

[0083] Figure 3 is a schematic diagram of the first air guide plate surface F11;

[0084] Figure 4 is a schematic diagram of the first air guide plate surface F12;

[0085] Figure 5 It is a schematic diagram of the projection of the center of the first small hole on F12;

[0086] Figure 6 is a schematic diagram of the first air guide plate surface F21;

[0087] Figure 7 is a schematic diagram of the first air guide plate surface F22;

[0088] Figure 8 This is a schematic diagram of the projection of the center of the third small hole on F22. DETAILED DESCRIPTION

[0089] The technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the invention.

[0090] Implementation Method 1

[0091] Figure 1 is a perspective view showing a temperature control air intake device according to an embodiment of the present invention. The plane side view of the temperature control air intake device can be referred to Figure 2 For ease of explanation, Figure 1 The first direction is called the x direction, the second direction is called the y direction, and the third direction is called the z direction. The thickness direction of the air guide plate, that is, the direction perpendicular to the largest surface of the air guide plate is called the z direction.

[0092] Reference Figure 1 or Figure 2 , the angle between the x direction and the y direction is θ, 0°<θ≤90°, for example, θ can be 30°, 45°, 60°, 90°, preferably θ=90°, that is, sinθ=1.

[0093] Reference Figure 1 or Figure 2 The temperature control air inlet device of the present invention comprises an air guide plate, which is suitable for introducing nitrogen into a muffle furnace containing alumina powder and carbon powder. The air guide plate is a hollow plate, and the vertical projection area of ​​the air guide plate is a parallelogram, preferably a rectangle; the lengths of the sides of the parallelogram in the x direction and the y direction are L1 and L2 respectively, and the area of ​​the parallelogram is S=L1*L2*sinθ.

[0094] L1 and L2 are both less than 1.5m, preferably 1.0-1.2m, for example, 1.0m, 1.1m, 1.2m.

[0095] The air guide plate includes a first air guide plate 10 and a second air guide plate 20; specifically, the first air guide plate 10 includes two largest opposite surfaces, namely F11 and F12, and the second air guide plate 20 includes two largest opposite surfaces, namely F21 and F22; the first air guide plate 10 and the second air guide plate 20 are parallel to each other, and the distance between the first air guide plate 10 and the second air guide plate 20 is h;

[0096] With regard to the above dimensions, in the present invention, the value range of h is 10 to 100 mm, preferably 30 to 80 mm, for example, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, and 80 mm.

[0097] Reference Figure 3 , F11 includes a plurality of first small holes 15, and the plurality of first small holes 15 form a first small hole group 13; on F11, the plurality of first small holes 15 form a first part 131, the first small holes 15 of the first part extend in the x direction and are evenly spaced, the plurality of first small holes 15 form a second part 132, the first small holes 15 of the second part extend in a direction parallel to the x direction and are evenly spaced, the spacing between the centers of the first small holes of the first part is equal to the spacing between the centers of the first small holes of the second part, and the spacing distance in the x direction is x. F11 ;

[0098] In the present invention, X F11 It refers to the distance between the centers of two adjacent first small holes 15 in the first part 131. F11 The ratio to L1 is 0.1 to 0.15, preferably 0.1 to 0.12, for example, 0.10, 0.11, or 0.12.

[0099] On F11, the first small hole group 13 is composed of a plurality of first parts 131 and second parts 132. The first parts 131 and second parts 132 are spaced equally from each other, and the spacing in the y direction is Y. F11 ;

[0100] In the present invention, the interval between the first part 131 and the second part 132 in the y direction refers to: the distance between the center of any first small hole in the first part 131 and the center of the first small hole in the second part 132 that is closest to it; F11 The ratio to L2 is 0.1 to 0.15, preferably 0.1 to 0.12, for example, 0.10, 0.11, or 0.12.

[0101] Reference Figure 4 , F12 includes a plurality of second small holes 16, and the plurality of second small holes 16 form a second small hole group 14; on F12, the plurality of second small holes 16 form a third part 141, and the second small holes 16 of the third part extend in the x direction and are evenly spaced, and the plurality of second small holes 16 form a fourth part 142, and the second small holes 16 of the fourth part extend in a direction parallel to the x direction and are evenly spaced, and the interval between the centers of the second small holes of the third part is equal to the interval between the centers of the second small holes of the fourth part, and the interval distance in the x direction is X. F12 ;

[0102] In the present invention, XF12 It refers to the distance between the centers of two adjacent second small holes 16 in the third part 141. F12 The ratio to L1 is 0.1 to 0.15, preferably 0.1 to 0.12, for example, 0.10, 0.11, or 0.12.

[0103] On F12, the second small hole group 14 is composed of a plurality of third parts 141 and fourth parts 142. The third parts 141 and the fourth parts 142 are spaced equally from each other, and the spacing in the y direction is Y. F12 ;

[0104] In the present invention, the interval between the third part 141 and the fourth part 142 in the y direction refers to: the distance between the center of any second small hole in the third part 141 and the center of the second small hole in the fourth part 142 that is closest to it; Y F12 The ratio to L2 is 0.1 to 0.15, preferably 0.1 to 0.12, for example, 0.10, 0.11, or 0.12.

[0105] Reference Figure 5 , the projection O11 of the center of the first small hole 15 on F12 does not coincide with the center O12 of the second small hole 16, and the straight-line distance between O11 and O12 is recorded as d1;

[0106] The value range of d1 is 40-200 mm, preferably 100-120 mm, for example, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm. Limiting the value range of d1 to the above range avoids the formation of through holes, helps to reduce the flow rate of nitrogen, preheats nitrogen more fully, and is not easy to blow away the powder in the furnace.

[0107] Reference Figure 6 , F21 includes a plurality of third small holes 25, and the plurality of third small holes 25 form a third small hole group 23; on F21, the plurality of third small holes 25 form a fifth part 231, and the third small holes 25 of the fifth part extend in the x direction and are evenly spaced, and the plurality of third small holes 25 form a sixth part 232, and the third small holes 25 of the sixth part extend in a direction parallel to the x direction and are evenly spaced, and the spacing between the centers of the third small holes of the fifth part is equal to the spacing between the centers of the third small holes of the sixth part, and the spacing distance in the x direction is X. F21 .

[0108] In the present invention, X F21 It refers to the distance between the centers of two adjacent third small holes 25 in the fifth part 231. F21 The ratio to L1 is 0.1 to 0.15, preferably 0.1 to 0.12, for example, 0.10, 0.11, or 0.12.

[0109] On F21, the third small hole group 23 is composed of a plurality of fifth parts 231 and sixth parts 232. The fifth parts 231 and the sixth parts 232 are spaced equally from each other, and the spacing in the y direction is Y. F21 ;

[0110] In the present invention, the interval between the fifth part 231 and the sixth part 232 in the y direction refers to: the distance between the center of any third small hole of the fifth part 231 and the center of the third small hole of the nearest sixth part 232; F21 The ratio to L2 is 0.1 to 0.15, preferably 0.1 to 0.12, for example, 0.10, 0.11, or 0.12.

[0111] Reference Figure 7 , F22 contains only one large hole 26 in the center;

[0112] Reference Figure 8 , the projection O21 of the center of the third small hole 25 on F22 does not coincide with the center O22 of the large hole 26 of F22.

[0113] In the present invention, the projection of the third small hole 25 on F12 coincides with the second small hole 16. The purpose of such arrangement is to make the subsequent connections of various parts tighter.

[0114] In the present invention, the total area of ​​the first small hole 15 is defined as S11, the total area of ​​the second small hole 16 is S12, and the total area of ​​the third small hole 25 is S21, S11, S12, and the ratios of S21, S11, S12 to the area S of the parallelogram are R11=S11 / S, R12=S12 / S, R21=S21 / S respectively; the area of ​​the large hole 26 is defined as S22, and the ratio of S22 to the area S of the parallelogram is R22=S22 / S.

[0115] In the present invention, the value range of R11 is 0.7 to 0.9, preferably 0.8 to 0.9, for example, 0.80, 0.82, 0.84, 0.86, 0.88, and 0.90.

[0116] In the present invention, the value range of R12 is 0.5 to 0.7, preferably 0.6 to 0.7, for example, 0.62, 0.64, 0.66, 0.68, 0.70.

[0117] In the present invention, the value range of R21 is 0.5 to 0.7, preferably 0.6 to 0.7, for example, 0.62, 0.64, 0.66, 0.68, 0.70.

[0118] In the present invention, the value range of R22 is 0.3 to 0.7, preferably 0.4 to 0.6, for example, 0.40, 0.45, 0.50, 0.55, 0.60.

[0119] In the present invention, the thickness range of the first air guide plate 10 is 10-100 mm, preferably 50-60 mm, for example, 52 mm, 54 mm, 56 mm, 58 mm, 60 mm; the thickness range of the second air guide plate 20 is 10-100 mm, preferably 50-60 mm, for example, 52 mm, 54 mm, 56 mm, 58 mm, 60 mm.

[0120] refer to Figure 1 or Figure 2 In the present invention, the temperature control air intake device also includes an air duct, which is divided into a first air duct 30 and a second air duct 40. The length of the first air duct 30 is recorded as a1, and the length of the second air duct 40 is recorded as a2. The a2 is equal to the distance h between the two air guide plates.

[0121] In the present invention, the value range of a1 is 50-100 mm, preferably 80-100 mm, for example, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm.

[0122] In the present invention, the value range of a2 is 10 to 100 mm, preferably 30 to 80 mm, for example, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, and 80 mm.

[0123] In the present invention, the projection of the inner wall of the first air duct 30 on F11 completely overlaps with the first small hole 15 , the projection of the inner wall of the second air duct 40 on F12 completely overlaps with the second small hole 16 , and the projection of the inner wall of the second air duct 40 on F21 completely overlaps with the third small hole 25 .

[0124] In the present invention, the projection shape of the first small hole, the second small hole, the third small hole, the large hole or the air guide tube on the air guide plate includes one or more combinations of triangles, parallelograms, pentagons, hexagons, and circles, and the preferred projection shape is a circle. In this embodiment, the projection shape is a circle, and the diameter of the circular projection shape of the first air guide tube 30 ranges from 5 to 20 mm, preferably from 10 to 20 mm, for example, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, and 20 mm; the diameter of the circular projection shape of the second air guide tube 40 ranges from 20 to 50 mm, preferably from 20 to 30 mm, for example, 22 mm, 24 mm, 26 mm, 28 mm, and 30 mm.

[0125] Reference Figure 1 or Figure 2In the present invention, the temperature-controlled air intake device further comprises an air intake pipe 50, the projection of the inner wall of the air intake pipe 50 on F22 completely coincides with the large hole 26; the flow rate of nitrogen in the air intake pipe 50 is in the range of 600 to 1200 L / min, preferably 800 to 1200 L / min, for example, 800 L / min, 900 L / min, 1000 L / min, 1100 L / min, 1200 L / min.

[0126] The temperature-controlled air intake device also includes a temperature-controlled device, which is filled with a preheating atmosphere.

[0127] In the present invention, the preheating atmosphere includes one or more combinations of air, nitrogen, and argon, preferably air.

[0128] The temperature-controlled air intake device comprises, from left to right, a first air guide duct 30, a first air guide plate 10, a second air guide duct 40, a second air guide plate 20, and an air intake duct 50, and each pipe opening is connected to a corresponding orifice in this order; the first air guide plate 10 is embedded in the side wall of the furnace body, the first air guide duct 30 enters the furnace body through the furnace wall, and the second air guide duct 40 and the second air guide plate 20 are both in a preheating atmosphere.

[0129] The present embodiment provides a method for preparing aluminum nitride powder: the preparation of aluminum nitride powder usually adopts a solid phase reaction method, in which the use of a temperature-controlled air inlet device to introduce nitrogen into the muffle furnace is a key step. The raw materials are 100 parts by mass of high-purity alumina powder and 150 parts by mass of carbon powder. The temperature of the muffle furnace needs to be accurately controlled between 900-1500°C. The nitrogen at room temperature is preheated by the temperature-controlled air inlet device and then stably transported to the furnace as a protective gas and a reaction gas. The flow rate and purity of nitrogen need to be precisely controlled, and a mass flow meter is usually used to adjust the flow rate to ensure that the nitrogen concentration in the reaction environment is constant. Alumina powder, carbon powder and nitrogen react with each other in the muffle furnace to generate aluminum nitride, and the reaction lasts for 10 hours. After the reaction is completed, the furnace temperature slowly drops to room temperature, the aluminum nitride powder is taken out, and its purity and particle size are improved by further cleaning and screening, and finally a high-quality aluminum nitride powder is obtained.

[0130] Implementation Method 2

[0131] In this embodiment, the center of any second small hole 16 of F12 is located at the center of the smallest parallelogram formed by projecting the centers of any four first small holes of F11 to F12. F11 =X F12 , Y F11 =Y F12 .

[0132] This embodiment is one of the preferred embodiments of the present invention, and the remaining features are the same as those of the first embodiment.

[0133] Implementation Method 3

[0134] In this embodiment, the projection shape of the first small hole, the second small hole, the third small hole, the large hole or the air guide tube on the air guide plate is a hexagon. The remaining features are the same as those of the first embodiment.

Claims

1. A method for preparing aluminum nitride powder, characterized in that: The method comprises the steps of introducing nitrogen into a muffle furnace containing alumina powder and carbon powder using a temperature-controlled air inlet device, wherein the temperature-controlled air inlet device comprises an air guide plate, wherein the air guide plate is a hollow plate, wherein the vertical projection area of ​​the air guide plate is a parallelogram, wherein the directions of two adjacent sides of the parallelogram are respectively recorded as a first direction and a second direction, wherein the side lengths of the parallelogram in the first direction and the second direction are respectively L1 and L2, wherein the angle between the first direction and the second direction is θ, and the area of ​​the parallelogram is as follows: S = L1*L2*sinθ; The air guide plate is divided into a first air guide plate and a second air guide plate; The two largest opposite surfaces of the first air guide plate are respectively denoted as F11 and F12, the F11 includes a plurality of first small holes, the plurality of the first small holes form a first small hole group, the F12 includes a plurality of second small holes, the plurality of the second small holes form a second small hole group; On the F11, a plurality of the first small holes form a first part, the first small holes of the first part extend in the first direction and are evenly spaced, a plurality of the first small holes form a second part, the first small holes of the second part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the first small holes of the first part is equal to the spacing between the centers of the first small holes of the second part, and the spacing distance in the first direction is X F11 The first small hole group is composed of a plurality of the first parts and the second parts, the first parts and the second parts are spaced equally from each other, and the spacing distance in the second direction is Y F11 ; On the F12, a plurality of the second small holes form a third part, the second small holes of the third part extend in the first direction and are evenly spaced, a plurality of the second small holes form a fourth part, the second small holes of the fourth part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the second small holes of the third part is equal to the spacing between the centers of the second small holes of the fourth part, and the spacing distance in the first direction is X F12 The second small hole group is composed of a plurality of the third part and the fourth part, the third part and the fourth part are equally spaced from each other, and the spacing distance in the second direction is Y F12 ; The projection O11 of the center of the first small hole on the F12 does not overlap with the center of the second small hole O12, and the straight-line distance between O11 and O12 is denoted as d1; The two largest opposite surfaces of the second air guide plate are respectively denoted as F21 and F22, the F21 comprises a plurality of third small holes, the plurality of third small holes constitute a third small hole group, and the F22 comprises only one large hole in the center; On the F21, a plurality of the third small holes form a fifth part, the third small holes of the fifth part extend in the first direction and are evenly spaced, a plurality of the third small holes form a sixth part, the third small holes of the sixth part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the third small holes of the fifth part is equal to the spacing between the centers of the third small holes of the sixth part, and the spacing distance in the first direction is X F21 The third group of small holes is composed of a plurality of the fifth part and the sixth part, the fifth part and the sixth part are equally spaced from each other, and the spacing distance in the second direction is Y F21 ; The projection of the third small hole on F12 coincides with the second small hole; The total area of ​​the first small holes is defined as S11, the total area of ​​the second small holes is defined as S12, and the total area of ​​the third small holes is defined as S21. The ratios of S11, S12, S21 to the area of ​​the parallelogram S are R11=S11 / S, R12=S12 / S, and R21=S21 / S, respectively. The area of ​​the large holes is defined as S22, and the ratio of S22 to the area of ​​the parallelogram S is R22=S22 / S. The first air guide plate and the second air guide plate are parallel to each other, and the distance between the first air guide plate and the second air guide plate is denoted as h; The temperature-controlled air intake device further includes an air duct, which is divided into a first air duct and a second air duct. The length of the first air duct is denoted as a1, and the length of the second air duct is denoted as a2, and a2 is equal to h. The projection of the inner wall of the first airway tube on F11 completely coincides with the first small hole, the projection of the inner wall of the second airway tube on F12 completely coincides with the second small hole, and the projection of the inner wall of the second airway tube on F21 completely coincides with the third small hole; The temperature-controlled air intake device further comprises an air intake pipe, the projection of the inner wall of the air intake pipe on the F22 completely coincides with the large hole; The temperature-controlled air intake device also includes a temperature control device, which is filled with a preheated atmosphere; The temperature-controlled air intake device is composed of a first air guide pipe, a first air guide plate, a second air guide pipe, a second air guide plate, and an air intake pipe from left to right, and each pipe opening is connected to a corresponding orifice in this order; the first air guide plate is embedded in the side wall of the furnace body, the first air guide pipe enters the furnace body through the furnace wall, and the second air guide pipe and the second air guide plate are both in a preheating atmosphere.

2. A temperature-controlled air intake device, characterized in that: The temperature control air intake device includes an air guide plate, which is a hollow plate. The vertical projection area of ​​the air guide plate is a parallelogram. The directions of two adjacent sides of the parallelogram are respectively recorded as the first direction and the second direction. The side lengths of the parallelogram in the first direction and the second direction are L1 and L2 respectively. The angle between the first direction and the second direction is θ. The area of ​​the parallelogram is as follows: S = L1*L2*sinθ; The air guide plate is divided into a first air guide plate and a second air guide plate; The two largest opposite surfaces of the first air guide plate are respectively denoted as F11 and F12, the F11 includes a plurality of first small holes, the plurality of the first small holes form a first small hole group, the F12 includes a plurality of second small holes, the plurality of the second small holes form a second small hole group; On the F11, a plurality of the first small holes form a first part, the first small holes of the first part extend in the first direction and are evenly spaced, a plurality of the first small holes form a second part, the first small holes of the second part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the first small holes of the first part is equal to the spacing between the centers of the first small holes of the second part, and the spacing distance in the first direction is X F11 The first small hole group is composed of a plurality of the first parts and the second parts, the first parts and the second parts are spaced equally from each other, and the spacing distance in the second direction is Y F11 ; On the F12, a plurality of the second small holes form a third part, the second small holes of the third part extend in the first direction and are evenly spaced, a plurality of the second small holes form a fourth part, the second small holes of the fourth part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the second small holes of the third part is equal to the spacing between the centers of the second small holes of the fourth part, and the spacing distance in the first direction is X F12 The second small hole group is composed of a plurality of the third part and the fourth part, the third part and the fourth part are equally spaced from each other, and the spacing distance in the second direction is Y F12 ; The projection O11 of the center of the first small hole on the F12 does not overlap with the center of the second small hole O12, and the straight-line distance between O11 and O12 is denoted as d1; The two largest opposite surfaces of the second air guide plate are respectively denoted as F21 and F22, the F21 comprises a plurality of third small holes, the plurality of third small holes constitute a third small hole group, and the F22 comprises only one large hole in the center; On the F21, a plurality of the third small holes form a fifth part, the third small holes of the fifth part extend in the first direction and are evenly spaced, a plurality of the third small holes form a sixth part, the third small holes of the sixth part extend in a direction parallel to the first direction and are evenly spaced, the spacing between the centers of the third small holes of the fifth part is equal to the spacing between the centers of the third small holes of the sixth part, and the spacing distance in the first direction is X F21 The third group of small holes is composed of a plurality of the fifth part and the sixth part, the fifth part and the sixth part are equally spaced from each other, and the spacing distance in the second direction is Y F21 ; The projection of the third small hole on F12 coincides with the second small hole; The total area of ​​the first small holes is defined as S11, the total area of ​​the second small holes is defined as S12, and the total area of ​​the third small holes is defined as S21. The ratios of S11, S12, S21 to the area of ​​the parallelogram S are R11=S11 / S, R12=S12 / S, and R21=S21 / S, respectively. The area of ​​the large holes is defined as S22, and the ratio of S22 to the area of ​​the parallelogram S is R22=S22 / S. The first air guide plate and the second air guide plate are parallel to each other, and the distance between the first air guide plate and the second air guide plate is denoted as h; The temperature-controlled air intake device further includes an air duct, which is divided into a first air duct and a second air duct. The length of the first air duct is denoted as a1, and the length of the second air duct is denoted as a2, and a2 is equal to h. The projection of the inner wall of the first airway tube on F11 completely coincides with the first small hole, the projection of the inner wall of the second airway tube on F12 completely coincides with the second small hole, and the projection of the inner wall of the second airway tube on F21 completely coincides with the third small hole; The temperature-controlled air intake device further comprises an air intake pipe, the projection of the inner wall of the air intake pipe on the F22 completely coincides with the large hole; The temperature-controlled air intake device also includes a temperature control device, which is filled with a preheated atmosphere; The temperature-controlled air intake device is composed of a first air guide pipe, a first air guide plate, a second air guide pipe, a second air guide plate, and an air intake pipe from left to right, and each pipe opening is connected to a corresponding orifice in this order; the first air guide plate is embedded in the side wall of the furnace body, the first air guide pipe enters the furnace body through the furnace wall, and the second air guide pipe and the second air guide plate are both in a preheating atmosphere.

3. The temperature control air intake device according to claim 2, characterized in that: The X F11 The ratio of Y to L1 is 0.1 to 0.15, preferably 0.1 to 0.

12. F11 The ratio of X to L2 is 0.1 to 0.15, preferably 0.1 to 0.

12. F12 The ratio of Y to L1 is 0.1 to 0.15, preferably 0.1 to 0.

12. F12 The ratio of X to L2 is 0.1 to 0.15, preferably 0.1 to 0.

12. F21 The ratio of Y to L1 is 0.1 to 0.15, preferably 0.1 to 0.

12. F21 The ratio to L2 is 0.1 to 0.15, preferably 0.1 to 0.

12.

4. The temperature control air intake device according to claim 2, characterized in that: The value range of d1 is 40-200 mm, preferably 100-120 mm.

5. The temperature control air intake device according to claim 2, characterized in that: The value range of R11 is 0.7 to 0.9, preferably 0.8 to 0.9, the value range of R12 is 0.5 to 0.7, preferably 0.6 to 0.7, the value range of R21 is 0.5 to 0.7, preferably 0.6 to 0.7, and the value range of R22 is 0.3 to 0.7, preferably 0.4 to 0.

6.

6. The temperature control air intake device according to claim 2, characterized in that: The value range of h is 10 to 100 mm, preferably 30 to 80 mm.

7. The temperature control air intake device according to claim 2, characterized in that: The value range of a1 is 50-100 mm, preferably 80-100 mm, and the value range of a2 is 10-100 mm, preferably 30-80 mm.

8. The temperature control air intake device according to claim 2, characterized in that: The thickness of the first air guide plate ranges from 10 to 100 mm, preferably from 50 to 60 mm, and the thickness of the second air guide plate ranges from 10 to 100 mm, preferably from 50 to 60 mm.

9. The temperature control air intake device according to claim 2, characterized in that: The projection shapes of the first small hole, the second small hole, the third small hole, the large hole or the air guide tube on the air guide plate include one or more combinations of triangle, parallelogram, pentagon, hexagon and circle, and the preferred projection shape is circle.

10. The temperature control air intake device according to claim 9, characterized in that: The diameter of the circular projection shape of the first air duct is in the range of 5 to 20 mm, preferably 10 to 20 mm; the diameter of the circular projection shape of the second air duct is in the range of 20 to 50 mm, preferably 20 to 30 mm.

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