A vacuum split nitriding furnace for processing silicon carbide powder and method thereof

Abstract

The present invention relates to the technical field of nitriding furnaces, and in particular to a vacuum split nitriding furnace for processing silicon carbide powder and a method thereof. The furnace comprises a nitriding furnace body and a condenser. By externally connecting the nitriding furnace to the condenser and a circulating pump, when the pressure in the nitriding furnace is stabilized, the circulating pump drives nitrogen-containing gas to circulate between the nitriding furnace and the condenser. In conjunction with a real-time gas replenishment mechanism, nitrogen and silicon powder can be fully reacted, and the high-temperature gas is cooled by the condenser and then pumped into the nitriding furnace by the circulating pump. This can protect the circulating pump and a piping system, remove gaseous by-products, and ensure gas circulation in the nitriding furnace, thereby solving the problems of unrecycled tail gas and poor gas flow in existing nitriding furnaces.

Description

Technical Field

[0001] The present invention relates to the technical field of nitriding furnaces, and in particular to a vacuum split nitriding furnace for processing silicon carbide powder and a method thereof. Background Art

[0002] Silicon carbide (SiC) powder is widely used in ceramics, refractories, semiconductors, and composite materials due to its excellent high-temperature stability, high hardness, corrosion resistance, and good thermal conductivity. However, in some applications, the surface properties of SiC powder need to be further optimized, such as by coating it with a layer of silicon nitride (Si3N4) to improve its oxidation resistance, enhance its high-temperature stability, or improve its interfacial bonding with other materials.

[0003] At present, the nitriding treatment of silicon carbide powder usually uses a high-temperature nitriding furnace, and the reaction is carried out in a nitrogen or ammonia atmosphere. That is, in a high-temperature nitrogen atmosphere, the surface of the silicon carbide powder reacts with nitrogen to produce silicon nitride. This process is usually carried out in a nitriding furnace. In the existing technology, molybdenum wire electric furnaces or molybdenum disilicide rod electric furnaces are mostly used as heating devices. The furnace must be strictly sealed, filled with silicon carbide powder and nitrogen is introduced. The reaction temperature is usually controlled at 970-1000℃. As the temperature increases, the reaction rate accelerates, and silicon nitride is eventually produced. However, the existing nitriding furnaces still have the following technical problems:

[0004] Exhaust gas is not recycled: Exhaust gas generated during the reaction is usually discharged directly into the atmosphere, which not only pollutes the environment, but also the residual nitrogen in the exhaust gas is not effectively recycled, resulting in a waste of resources. Poor gas flow: If the gas flow in the furnace is uneven or fails to fully contact the silicon carbide powder, the silicon powder nitridation reaction will be incomplete or the reaction will be uneven in some areas, affecting the quality and performance of the final product. Summary of the Invention

[0005] In response to the problems existing in the prior art, a vacuum split nitriding furnace for processing silicon carbide powder and a method thereof are provided. By connecting the nitriding furnace to a condenser and a circulating pump, when the pressure in the nitriding furnace is stable, the circulating pump drives the nitrogen-containing gas to circulate between the nitriding furnace and the condenser, and cooperates with a real-time gas replenishment mechanism, so that the nitrogen and silicon powder can be fully reacted, and the high-temperature gas is cooled by the condenser and then pumped into the nitriding furnace by the circulating pump, which can protect the circulating pump and the piping system, remove gaseous by-products and ensure the gas circulation in the nitriding furnace, thereby solving the problems of the existing nitriding furnace tail gas not being recycled and the gas flow being poor.

[0006] In order to solve the problems of the prior art, the present invention provides a vacuum split nitriding furnace for processing silicon carbide powder, comprising a nitriding furnace body and a condenser, wherein the nitriding furnace body is provided with a nitrogen-containing gas inlet, a vacuum port, a circulating gas outlet and a circulating gas inlet, and the gas in the nitriding furnace body circulates between the nitriding furnace body and the condenser; the nitriding furnace body comprises a furnace body and a furnace chamber arranged in the furnace body, the furnace chamber is provided with brackets arranged at equal intervals in the vertical direction, trays are provided on the brackets at equal intervals, an air cavity connected to the nitrogen-containing gas inlet and the circulating gas inlet is provided at the bottom of the tray, a rectangular array at the top of the air cavity is provided with air holes, and the nitrogen-containing gas passes through the silicon powder contained in the tray through the air holes; a side cavity connected to the nitrogen-containing gas inlet and the circulating gas inlet is formed between a movable plate and a side surface of the air cavity, and when the pressure of the side cavity is greater than the abutment pressure of the movable plate on the air holes, the movable plate moves downward relative to the air holes.

[0007] Preferably, the top rectangular array of the movable plate has plugs, the top of the plugs is provided with plug heads that can be engaged with the air holes, and a pressure chamber connected to the side chamber is formed between the top of the movable plate and the top of the air cavity.

[0008] Preferably, an elastic reset element is provided between the bottom end of the movable plate and the bottom end of the air cavity, and when the pressure of the side cavity is greater than the elastic force of the elastic reset element, the movable plate moves downward relative to the air hole.

[0009] Preferably, a nitrogen-containing gas diversion pipe rack connected to the nitrogen-containing gas inlet is provided in the nitriding furnace body, and a circulating gas diversion pipe rack connected to the circulating gas inlet is also provided in the nitriding furnace body. A nitrogen-containing gas pipe capable of communicating with the nitrogen-containing gas diversion pipe rack is provided on the bracket, and the nitrogen-containing gas pipe is connected to the air cavity; a circulating gas pipe capable of communicating with the circulating gas inlet is also provided on the bracket, and the circulating gas pipe is connected to the air cavity.

[0010] Preferably, a first one-way conducting member is provided at the connection between the nitrogen-containing gas pipe and the gas cavity, and a second one-way conducting member is provided at the connection between the circulating gas pipe and the gas cavity.

[0011] Preferably, the first one-way conducting member and the second one-way conducting member have the same structure, the first one-way conducting member includes a valve seat, a valve block and a valve ball, the valve seat is arranged in a bracket and a conical opening connected to the nitrogen-containing gas pipe is provided on the top thereof, the valve block is slidably arranged in the valve seat, the gate block has an inclined groove and a valve cylinder that passes through the valve seat and can be connected to the air cavity, the valve cylinder is located on the outside of the valve seat and is provided with a positioning ring and an elastic buffer element, the elastic buffer element is located between the positioning ring and the inner wall of the bracket, the valve ball is located in the inclined groove and elastically abuts against the conical opening.

[0012] Preferably, one end of the valve cylinder passes through the bracket and forms an abutting cone head, and the side of the tray is provided with an interlocking air port that can be interlocked with the abutting cone head, and the interlocking air port is communicated with the air cavity.

[0013] A vacuum split nitriding method for processing silicon carbide powder, using a vacuum split nitriding furnace for processing silicon carbide powder, comprises the following steps:

[0014] Step 1: vacuum the nitriding furnace body through the vacuum hole;

[0015] Step 2: injecting nitrogen-containing gas into the nitriding furnace body through the nitrogen-containing gas inlet;

[0016] Step 3: After the pressure in the nitriding furnace body reaches the specified pressure, the gas injection is stopped and the circulation pump is started to circulate the gas between the nitriding furnace body and the condenser;

[0017] Step 4: The nitriding furnace body is heated to nitride the silicon carbide powder into a shape.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The present application sets a circulation pump and a condenser to allow the nitrogen-containing gas to circulate continuously between the nitriding furnace and the condenser, which not only improves the utilization rate of nitrogen and reduces gas waste, but also enhances the reaction efficiency of nitrogen and silicon powder, thereby significantly improving the efficiency of the nitriding reaction.

[0020] This application avoids direct exhaust gas discharge by cooling the high-temperature gas generated during the nitriding process through a condenser and then recirculating it for reuse, effectively reducing the overflow of gaseous by-products during the nitriding reaction, reducing pollution to the environment, and achieving green and clean production.

[0021] This application significantly reduces the gas temperature by cooling the high-temperature exhaust gas through a condenser before entering the circulation pump, effectively protecting the circulation pump and piping system from erosion by high-temperature gas, thereby extending the service life of the equipment and improving the reliability and safety of the system operation.

[0022] This application also effectively improves the uniformity of gas distribution within the silicon powder through the design of the air cavity and air holes, thereby accelerating the nitridation reaction process, reducing the nitridation time, and ensuring the uniformity and stability of the reaction. This allows the gas to more evenly penetrate the entire silicon powder layer, avoiding the limitation of gas contact only with the surface layer in traditional systems and reducing unnecessary gas waste. The uniform airflow and clear gas channels reduce high temperature accumulation or system failure caused by unstable airflow, thereby improving the safety of the nitridation process and the life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of a vacuum split nitriding furnace for processing silicon carbide powder according to the present invention.

[0024] Figure 2The present invention is a three-dimensional diagram of a nitriding furnace body in a vacuum split nitriding furnace for processing silicon carbide powder.

[0025] Figure 3 The present invention is a cross-sectional view of a nitriding furnace body in a vacuum split nitriding furnace for processing silicon carbide powder.

[0026] Figure 4 yes Figure 3 A partial enlarged view of point A.

[0027] Figure 5 The present invention is a schematic diagram of a vacuum split nitriding furnace for processing silicon carbide powder when nitrogen-containing gas is introduced.

[0028] Figure 6 The figure is a schematic diagram of the internal structure of a vacuum split nitriding furnace for processing silicon carbide powder according to the present invention.

[0029] Figure 7 The present invention is a schematic diagram of a bracket and a tray in a vacuum split nitriding furnace for processing silicon carbide powder.

[0030] Figure 8 The present invention is a three-dimensional exploded view of a bracket and a tray in a vacuum split nitriding furnace for processing silicon carbide powder.

[0031] Figure 9 The present invention is a three-dimensional diagram of a first one-way conducting member in a vacuum split nitriding furnace for processing silicon carbide powder.

[0032] Figure 10 The present invention is a perspective exploded view of a second one-way conducting member in a vacuum split nitriding furnace for processing silicon carbide powder.

[0033] The numbers in the figure are: 1. Nitriding furnace body; 111. Nitrogen-containing gas inlet; 112. Vacuum port; 113. Circulating gas outlet; 114. Circulating gas inlet; 12. Furnace body; 13. Furnace chamber; 131. Positioning block; 14. Bracket; 141. Sliding plate; 142. Nitrogen-containing gas pipe; 143. Circulating gas pipe; 15. Tray; 152. Air hole; 153. Fitting air port; 16. Movable plate; 161. Side cavity; 162. Plug; 163. Plug; 164. Pressure cavity; 17. elastic reset element; 181. nitrogen-containing gas diversion pipe rack; 182. circulating gas diversion pipe rack; 183. first one-way conducting member; 1831. valve seat; 1832. valve block; 1833. valve ball; 1834. valve cylinder; 1835. positioning ring; 1836. elastic buffer element; 184. second one-way conducting member; 2. condenser; 21. superheated gas inlet; 22. low-temperature gas outlet; 3. first circulation pipe; 4. second circulation pipe; 5. circulation pump. DETAILED DESCRIPTION

[0034] In order to further understand the features, technical means, specific objectives and functions achieved by the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] like Figure 1 、 Figure 2 and Figure 3 As shown, a vacuum split nitriding furnace for processing silicon carbide powder includes a nitriding furnace body 1 and a condenser 2. The nitriding furnace body 1 is provided with a nitrogen-containing gas inlet 111, a vacuum port 112, a circulating gas outlet 113 and a circulating gas inlet 114. The condenser 2 has a superheated gas inlet 21 and a low-temperature gas outlet 22. A first circulating pipe 3 is provided between the circulating gas outlet 113 and the superheated gas inlet 21, and a second circulating pipe 4 is provided between the low-temperature gas outlet 22 and the circulating gas inlet 114. A circulating pump 5 is provided on the second circulating pipe 4. The circulating pump 5 is used to guide the low-temperature gas discharged from the condenser 2 to flow back into the nitriding furnace circulating pump 5 body. After the nitriding furnace body 1 is vacuumed, nitrogen-containing gas is injected into the nitriding furnace body 1 through the nitrogen-containing gas inlet 111. When the internal pressure of the nitriding furnace body 1 reaches the set value, the injection of nitrogen-containing gas is stopped, and the circulating pump 5 is started for gas circulation.

[0036] A vacuum split nitriding furnace system for processing silicon carbide powder includes a nitriding furnace body 1, a condenser 2, a circulation pump 5, a first circulation pipe 3, and a second circulation pipe 4. This system features gas circulation, heat recovery, and real-time gas replenishment, aiming to improve nitriding efficiency, protect equipment, and utilize tail gas.

[0037] The structure configuration is as follows:

[0038] Nitriding furnace body 1: equipped with nitrogen-containing gas inlet 111, vacuum port 112, circulating gas outlet, circulating gas inlet, and a pressure sensor (pressure gauge) is provided inside for real-time monitoring of the pressure in the furnace.

[0039] Condenser 2: having a high-temperature gas inlet and a low-temperature gas outlet 22, and is used to cool the superheated tail gas generated during the nitriding process to achieve condensation of gaseous by-products and gas recycling.

[0040] Circulation piping system:

[0041] The first circulation pipe 3 connects the circulation gas outlet 113 of the nitriding furnace body 1 and the superheated gas inlet 21 of the condenser 2 .

[0042] The second circulation pipe 4 connects the low-temperature gas outlet 22 of the condenser 2 and the circulation gas inlet 114 of the nitriding furnace body 1 .

[0043] The circulation pump 5 is provided in the second circulation pipe 4 and is used to push the cooled gas to flow back into the nitriding furnace to form a closed-loop gas flow system.

[0044] Workflow and control mechanism:

[0045] Vacuuming and filling: After the system is started, the nitriding furnace body 1 is first vacuumed through the vacuum port 112 to remove residual air in the furnace; then nitrogen-containing gas (such as nitrogen or ammonia mixed gas) is injected through the nitrogen-containing gas inlet 111.

[0046] Pressure monitoring and gas replenishment control: When the furnace pressure reaches the set value, gas replenishment automatically stops. A pressure gauge installed in the furnace monitors the pressure in real time. When the pressure falls below the set threshold, the system automatically replenishes gas through the nitrogen-containing gas inlet 111, implementing a real-time gas replenishment mechanism to maintain reaction stability.

[0047] Gas circulation and thermal management:

[0048] The high-temperature nitrogen-containing tail gas generated during the nitriding process is introduced into the condenser 2 through the first circulation pipe 3.

[0049] The condenser 2 cools the high-temperature exhaust gas, condensing by-products (such as nitrogen oxides and volatile impurities) on the one hand, and reducing the gas temperature to protect the circulation pump 5 and pipelines on the other hand.

[0050] The cooled low-temperature gas flows back to the nitriding furnace through the second circulation pipe 4 under the promotion of the circulation pump 5, so as to realize the recycling of the gas.

[0051] like Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 8 As shown, the nitriding furnace body 1 includes a furnace body 12 and a furnace chamber 13 arranged in the furnace body 12, and the furnace chamber 13 is provided with brackets 14 arranged at equal intervals in the vertical direction, and trays 15 are arranged at equal intervals on the brackets 14. The bottom of the tray 15 is provided with an air cavity connected to the nitrogen-containing gas inlet 111 and the circulating gas inlet 114, and the top of the air cavity is provided with a rectangular array of air holes 152, and the nitrogen-containing gas passes through the air holes 152 to pass through the silicon powder contained in the tray 15.

[0052] By providing an air cavity and air holes 152 at the bottom of tray 15, the nitrogen-containing gas is evenly distributed throughout the tray 15 through the air holes 152 within the air cavity, thus avoiding the problem of gas contacting only the surface of the silicon powder in traditional nitriding furnaces. This design ensures that the gas effectively penetrates the entire silicon powder layer, achieving a full reaction between the gas and the silicon powder and improving nitriding efficiency.

[0053] During the nitriding process, the nitriding reaction of the silicon powder occurs not only on the surface but also penetrates deep into the silicon powder. The design of the air cavity and pores 152 ensures that the nitrogen-containing gas can pass through the silicon powder layer more evenly, avoiding the problems of uneven gas flow and incomplete localized reaction in traditional methods, significantly improving the uniformity of the reaction and the nitriding effect of the silicon powder.

[0054] The uniform arrangement of air holes 152 ensures a stable gas flow through tray 15, preventing localized overheating caused by overly concentrated or rapid airflow. Furthermore, the air cavity design provides a larger flow area for the gas, further improving system stability and reducing the risk of reaction instability or equipment failure caused by uneven airflow distribution.

[0055] Sliding plates 141 are provided on both sides of the bracket 14, and a sliding groove cooperating with the sliding plate 141 is provided in the furnace 13. The bracket 14 is pushed into the sliding groove through the sliding plate 141, and a positioning block 131 that can elastically abut against the top of the sliding plate 141 is provided at the top of the sliding groove. The bottom ends of the positioning block 131 are chamfered on both sides, and the top end of the sliding plate 141 is provided with a groove that can be engaged with the bottom end of the positioning block 131. When the sliding plate 141 is pushed into the sliding groove and reaches the specified position, the positioning block 131 is engaged with the groove.

[0056] The bottom of positioning block 131 features chamfered corners on both sides, while the top of sliding plate 141 is fitted with a groove that precisely mates with the bottom of positioning block 131. This mechanically interlocking locking design effectively prevents movement of bracket 14 due to gas pressure or vibration during pressurization. The interaction between positioning block 131 and the groove ensures the stability of bracket 14 throughout operation, preventing process instability caused by loosening or displacement of bracket 14.

[0057] The positioning block 131 abuts against the top of the sliding plate 141 through an elastic element. When the sliding plate 141 is pushed into a specified position, the elastic positioning block 131 will automatically and elastically snap into the groove to achieve automatic locking without the need for additional mechanical intervention.

[0058] During the nitriding process, changes in the gas pressure within furnace 13 can affect bracket 14. The interlocking design of positioning block 131 and the groove effectively prevents bracket 14 from moving. Even under high pressure, bracket 14 remains firmly in place, ensuring stability during the nitriding process and consistent reaction. This design reduces the risk of uneven gas distribution and incomplete reaction caused by displacement of bracket 14.

[0059] like Figure 4 and Figure 5As shown, a movable plate 16 capable of abutting against the bottom of the air hole 152 is provided in the air cavity, and a side cavity 161 connected to the nitrogen-containing gas inlet 111 and the circulating gas inlet 114 is formed between the movable plate 16 and the side of the air cavity. When the pressure of the side cavity 161 is greater than the abutting pressure of the movable plate 16 on the air hole 152, the movable plate 16 moves downward relative to the air hole 152.

[0060] During the silicon powder loading stage, since the movable plate 16 is in the upper position, it is close to the bottom of the air hole 152, effectively closing the air hole 152 channel, forming a physical barrier to prevent silicon powder from falling through the air hole 152 into the air cavity below, avoiding clogging the channel or contaminating the inside of the air cavity.

[0061] The pressure in side chamber 161 is dynamically controlled by connecting to nitrogen-containing gas inlet 111 and circulating gas inlet 114. During the reaction phase, gas begins to be injected, increasing the pressure in side chamber 161. This pressure drives movable plate 16 downward, overcoming its elastic resistance and releasing its seal. This automatically opens the airflow channel, allowing nitrogen-containing gas to flow smoothly into tray 15 through air holes 152.

[0062] The movable plate 16 can automatically return to its original abutment position after the airflow stops, blocking the possibility of dust, residue or unreacted silicon powder falling back into the air cavity, further reducing the maintenance frequency and risk, and improving the continuous working ability of the equipment.

[0063] like Figure 4 and Figure 5 As shown, the top rectangular array of the movable plate 16 has plugs 162, and the top of the plugs 162 is provided with plug heads 163 that can be engaged with the air holes 152. A pressure chamber 164 connected to the side chamber 161 is formed between the top of the movable plate 16 and the top of the air cavity.

[0064] During the injection process, the precise fit between plug 163 and pore 152 effectively prevents silicon powder particles from entering pore 152, thereby avoiding the risk of clogging pore 152. Silicon powder particles vary in size and are prone to forming blockages due to friction or accumulation between particles. However, the design of plug 163 ensures that pore 152 remains unobstructed.

[0065] Pressure chamber 164 communicates with side chamber 161, utilizing changes in airflow or air pressure to adjust the position of movable plate 16. If airflow needs to be released or subsequent reaction steps are required, the air pressure within side chamber 161 pushes movable plate 16, which in turn pushes plug 163 away from air hole 152, opening the airflow channel. This pressure change automatically releases the seal of plug 163 when needed, ensuring smooth airflow and the proper progress of the reaction.

[0066] like Figure 4 and Figure 5As shown, an elastic reset element 17 is provided between the bottom end of the movable plate 16 and the bottom end of the air cavity. When the pressure of the side cavity 161 is greater than the elastic force of the elastic reset element 17 , the movable plate 16 moves downward relative to the air hole 152 .

[0067] An elastic reset element 17 is provided between the bottom end of the movable plate 16 and the bottom end of the air cavity. It is usually a spring or a similar elastic element, which can generate a certain reset force on the movable plate 16 when the pressure in the side cavity 161 changes.

[0068] This design ensures that the movable plate 16 can move flexibly under the action of external pressure, and when the pressure disappears or returns to normal, the elastic reset element 17 can restore the movable plate 16 to its original position.

[0069] When the pressure in the side chamber 161 exceeds the elastic force of the elastic reset element 17, the movable plate 16 moves downward relative to the air hole 152, pushing the plug 163 out of the air hole 152 and opening the air flow channel. This downward movement allows the air hole 152 to remain open when needed, ensuring smooth airflow and the reaction.

[0070] On the contrary, if the pressure in the side cavity 161 decreases, the elastic reset element 17 will use its elastic force to bring the movable plate 16 back to its original position, so that the plug 163 is re-engaged with the air hole 152, sealing the air hole 152 to prevent excessive airflow or silicon powder from entering the air hole 152.

[0071] like Figure 3 、 Figure 6 and Figure 7 As shown, the nitriding furnace body 1 is provided with a nitrogen-containing gas diversion pipe rack 181 connected to the nitrogen-containing gas inlet 111, and the nitriding furnace body 1 is also provided with a circulating gas diversion pipe rack 182 connected to the circulating gas inlet 114. The bracket 14 is provided with a nitrogen-containing gas pipe 142 that can be connected to the nitrogen-containing gas diversion pipe rack 181, and the nitrogen-containing gas pipe 142 is connected to the air cavity; the bracket 14 is also provided with a circulating gas pipe 143 that can be connected to the circulating gas inlet 114, and the circulating gas pipe 143 is connected to the air cavity.

[0072] Nitrogen-containing gas distribution system: Nitrogen-containing gas inlet 111 → nitrogen-containing gas distribution rack 181 → nitrogen-containing gas pipe 142 → gas cavity. This channel constitutes the fresh nitrogen source supply for the entire system. The distribution rack functions to evenly distribute the nitrogen entering from the inlet to multiple nitrogen-containing gas pipes 142. These pipes are then connected to corresponding gas cavities, providing an independent and stable nitrogen source supply to each reaction unit. This enables multi-channel parallel gas supply, improving nitriding uniformity.

[0073] The circulating gas distribution system: circulating gas inlet 114 → circulating gas distribution pipe rack 182 → circulating gas pipe 143 → gas cavity. This system constitutes the gas loop circulation portion. Used gas re-enters the furnace body 12 through a specific method (such as purification or heat exchange) and then enters the various gas cavities through the circulating gas distribution pipe rack 182, achieving resource reuse and regulating the system's thermal balance. This creates a closed cycle and conserves gas resources.

[0074] like Figure 3 As shown, a first one-way conducting member 183 is provided at the connection between the nitrogen-containing gas pipe 142 and the gas cavity, and a second one-way conducting member 184 is provided at the connection between the circulating gas pipe 143 and the gas cavity.

[0075] First one-way guide 183 is located at the junction of nitrogen-containing gas pipe 142 and the gas cavity. Its primary function is to prevent the backflow of nitrogen-containing gas during the circulation of circulating gas. During normal operation, nitrogen-containing gas enters the gas cavity through this guide. However, when the pressure in the gas cavity changes or the circulating gas flows, the guide closes, preventing external gas from flowing back into nitrogen-containing gas pipe 142, thus ensuring unidirectional gas distribution.

[0076] A second one-way passage 184, located at the junction of the circulating gas pipe 143 and the gas cavity, prevents backflow of the circulating gas during the injection of nitrogen-containing gas. Specifically, during nitrogen-containing gas injection, the second one-way passage 184 automatically closes, preventing newly injected nitrogen-containing gas from entering the circulating pipe, thus ensuring the complete independence of the two gas systems.

[0077] like Figure 4 、 Figure 9 and Figure 10 As shown, the first one-way conducting member 183 and the second one-way conducting member 184 have the same structure. The first one-way conducting member 183 includes a valve seat 1831, a valve block 1832 and a valve ball 1833. The valve seat 1831 is arranged in the bracket 14 and a conical port connected to the nitrogen-containing gas pipe 142 is provided on the top thereof. The valve block 1832 is slidingly arranged in the valve seat 1831. The gate block has an inclined groove and a valve cylinder 1834 that passes through the valve seat 1831 and can be connected to the air cavity. The valve cylinder 1834 is located on the outside of the valve seat 1831 and is provided with a positioning ring 1835 and an elastic buffer element 1836. The elastic buffer element 1836 is located between the positioning ring 1835 and the inner wall of the bracket 14. The valve ball 1833 is located in the inclined groove and elastically abuts against the conical port.

[0078] When the pressure of the gas flowing in the nitrogen-containing gas pipe 142 reaches a certain value, the pressure on the top of the valve ball 1833 increases, causing the valve ball 1833 to slide downward along the inclined groove of the valve block 1832. At this point, the sealing contact point between the valve ball 1833 and the valve seat 1831 is broken, forming a channel between the nitrogen-containing gas pipe 142 and the valve seat 1831, thereby achieving gas communication.

[0079] Because valve ball 1833 is seated in the inclined groove of valve block 1832, the sliding of valve block 1832 is accompanied by the movement of valve ball 1833. Specifically, when valve ball 1833 moves downward, valve block 1832 is able to overcome the elastic force provided by elastic buffer element 1836 (typically a spring or similar flexible element), thereby pushing valve block 1832 downward while connected to valve seat 1831, thereby guiding the passage between valve cylinder 1834 and the air cavity to open, establishing effective communication between nitrogen-containing gas pipe 142 and the air cavity.

[0080] During this process, changes in the pressure within the air chamber also affect the operation of valve block 1832 and valve ball 1833. When the air pressure within the air chamber increases, valve block 1832 automatically reverses its movement, resealing the passage. At this point, valve ball 1833, due to its structure and elastic design, returns to its original position, re-engaging with the tapered opening and preventing any reverse flow of gas, preventing it from flowing back into the air chamber through nitrogen-containing gas pipe 142.

[0081] like Figure 4 、 Figure 9 and Figure 10 As shown, one end of the valve cylinder 1834 passes through the bracket 14 and forms an abutting cone head. The side of the tray 15 is provided with an interlocking air port 153 that can be interlocked with the abutting cone head. The interlocking air port 153 is communicated with the air cavity.

[0082] The interlocking gas port 153 communicates with the air cavity, allowing the gas inside the valve cylinder 1834 to be smoothly channeled into the cavity. This completes a closed-loop path for high-pressure gas to enter the cavity from the nitrogen-containing gas pipe 142 via the conductive structure. The conical contact between the abutting cone head and the interlocking gas port 153 ensures stability under multi-directional airflow, preventing the tray 15 from shifting or shaking horizontally or vertically due to sudden airflow pressure.

[0083] A vacuum split nitriding method for processing silicon carbide powder, using a vacuum split nitriding furnace for processing silicon carbide powder, comprises the following steps:

[0084] Step 1: vacuuming the nitriding furnace body 1 through the vacuum hole;

[0085] Step 2: injecting nitrogen-containing gas into the nitriding furnace body 1 through the nitrogen-containing gas inlet 111;

[0086] Step 3: After the pressure in the nitriding furnace body 1 reaches the specified pressure, the gas injection is stopped and the circulation pump 5 is started to circulate the gas between the nitriding furnace body 1 and the condenser 2;

[0087] Step 4: The nitriding furnace body 1 is heated to nitridate and shape the silicon carbide powder.

[0088] The above embodiments merely represent one or more embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of protection of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, and such modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the appended claims.

Claims

1. A vacuum split nitriding furnace for processing silicon carbide powder, characterized in that: The nitriding furnace comprises a main body and a condenser. The main body of the nitriding furnace is provided with a nitrogen-containing gas inlet, a vacuum port, a circulating gas outlet and a circulating gas inlet. The gas in the nitriding furnace main body circulates between the main body of the nitriding furnace and the condenser. The nitriding furnace body includes a furnace body and a furnace chamber arranged in the furnace body. The furnace chamber is provided with brackets arranged at equal intervals in the vertical direction. Trays are arranged at equal intervals on the brackets. An air cavity connected to a nitrogen-containing gas inlet and a circulating gas inlet is provided at the bottom of the tray. A rectangular array of air holes is provided at the top of the air cavity. The nitrogen-containing gas passes through the air holes and passes through the silicon powder contained in the tray. The air cavity is provided with a movable plate capable of abutting against the bottom of the air hole, and a side cavity is formed between the movable plate and the side of the air cavity, which is connected to the nitrogen-containing gas inlet and the circulating gas inlet. When the pressure of the side cavity is greater than the abutting pressure of the movable plate on the air hole, the movable plate moves downward relative to the air hole; The nitriding furnace body is provided with a nitrogen-containing gas diversion pipe rack connected to the nitrogen-containing gas inlet, and the nitriding furnace body is also provided with a circulating gas diversion pipe rack connected to the circulating gas inlet. A nitrogen-containing gas pipe capable of communicating with the nitrogen-containing gas diversion pipe rack is provided on the bracket, and the nitrogen-containing gas pipe is connected to the gas cavity; the bracket is also provided with a circulating gas pipe capable of communicating with the circulating gas inlet, and the circulating gas pipe is connected to the gas cavity; A first one-way conducting member is provided at the connection point between the nitrogen-containing gas pipe and the gas cavity, and a second one-way conducting member is provided at the connection point between the circulating gas pipe and the gas cavity.

2. A vacuum split nitriding furnace for processing silicon carbide powder according to claim 1, characterized in that: The top of the movable plate is provided with a rectangular array of plugs, and the top of the plugs is provided with plugs that can be engaged with the air holes. A pressure chamber connected to the side chamber is formed between the top of the movable plate and the top of the air cavity.

3. A vacuum split nitriding furnace for processing silicon carbide powder according to claim 1 or 2, characterized in that: An elastic reset element is provided between the bottom end of the movable plate and the bottom end of the air cavity. When the pressure of the side cavity is greater than the elastic force of the elastic reset element, the movable plate moves downward relative to the air hole.

4. The vacuum split nitriding furnace for processing silicon carbide powder according to claim 1, characterized in that: The first one-way conducting member and the second one-way conducting member have the same structure. The first one-way conducting member includes a valve seat, a valve block and a valve ball. The valve seat is arranged in a bracket and a tapered port connected to the nitrogen-containing gas pipe is provided on the top thereof. The valve block is slidably arranged in the valve seat. The gate block has an inclined groove and a valve cylinder that passes through the valve seat and can be connected to the air cavity. The valve cylinder is located on the outside of the valve seat and is provided with a positioning ring and an elastic buffer element. The elastic buffer element is located between the positioning ring and the inner wall of the bracket. The valve ball is located in the inclined groove and elastically abuts against the tapered port.

5. A vacuum split nitriding furnace for processing silicon carbide powder according to claim 4, characterized in that: One end of the valve cylinder passes through the bracket and forms an abutting cone head. The side of the tray is provided with an embedding air port that can be embedded with the abutting cone head. The embedding air port is communicated with the air cavity.

6. A vacuum split nitriding method for processing silicon carbide powder, characterized in that: The vacuum split nitriding furnace for processing silicon carbide powder according to claim 1 or 2 comprises the following steps: Step 1: vacuum the nitriding furnace body through the vacuum hole; Step 2: injecting nitrogen-containing gas into the nitriding furnace body through the nitrogen-containing gas inlet; Step 3: After the pressure in the nitriding furnace body reaches the specified pressure, the gas injection is stopped and the circulation pump is started to circulate the gas between the nitriding furnace body and the condenser; Step 4: The nitriding furnace body is heated to nitride the silicon carbide powder into a shape.

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