Composite silicon carbide push plate for industrial kiln and preparation method

Abstract

The invention discloses a composite silicon carbide push plate for an industrial kiln, which comprises a plurality of push plate main bodies, every two adjacent push plate main bodies are detachably connected through an edge connecting structure, and each push plate main body sequentially comprises a base layer made of a silicon carbide material and internally provided with a plurality of uniformly distributed reinforcing ribs from inside to outside, the reinforcing ribs are of a latticed structure. The transition layer is formed by compounding silicon carbide particles and metal silicon; and the working surface layer is formed by compounding nano silicon carbide and a carbon fiber composite reinforced material, and the outer surface of the working surface layer is ground and then is provided with an anti-oxidation film layer and a nano silicon carbide coating. Thus, the three-layer composite structure is combined with the reinforcing ribs, the overall structural strength is improved, internal stress caused by thermal expansion coefficient difference is effectively reduced, the problem that cracks are generated due to thermal stress concentration at the high temperature is solved, the abrasion resistance is remarkably improved through the nano silicon carbide coating, and the service life is prolonged; normal operation of the kiln is guaranteed, and production efficiency of the kiln is improved.

Description

Technical Field

[0001] This invention relates to the field of industrial kiln accessories technology, and in particular to a composite silicon carbide pusher plate for industrial kilns and its preparation method. Background Technology

[0002] In the production process of industrial kilns, silicon carbide products are widely used in key components of kilns due to their excellent high temperature resistance, wear resistance, and high strength. For example, silicon carbide pusher plates are key components for material conveying.

[0003] Existing silicon carbide pusher plates are mostly of a single structure, which has the following defects: they are prone to cracking due to thermal stress concentration at high temperatures, and their insufficient wear resistance leads to a short service life, affecting the normal operation and production efficiency of the kiln; moreover, the overall structural strength is difficult to meet the high load requirements of large industrial kilns.

[0004] Therefore, there is an urgent need for a new type of high-performance composite silicon carbide pusher for industrial kilns. Summary of the Invention

[0005] To address the technical problems existing in the background art, the present invention proposes a composite silicon carbide pusher plate for industrial kilns and its preparation method.

[0006] This invention proposes a composite silicon carbide pusher plate for industrial kilns, comprising multiple pusher plate bodies, wherein adjacent pusher plate bodies are detachably connected by an edge connection structure, and the pusher plate bodies, from the inside to the outside, comprise:

[0007] The base layer is made of silicon carbide material and has several evenly distributed reinforcing ribs inside, which are in a grid structure.

[0008] The transition layer is composed of silicon carbide particles and metallic silicon.

[0009] The working surface layer is made of composite material of nano-silicon carbide and carbon fiber. Its outer surface is ground and then coated with an anti-oxidation film layer and a nano-silicon carbide coating.

[0010] Preferably, the base layer has a heat dissipation channel connected to an external cooling source. The heat dissipation channel is serpentine in shape, with both ends extending to the two sides of the push plate body. The cross-sectional shape of the heat dissipation channel is circular, and its diameter is determined according to the size of the push plate body and the heat dissipation requirements.

[0011] Preferably, a weight-reducing cavity is provided at each of the four corners of the bottom of the base layer, and the opening of the weight-reducing cavity is sealed with a detachable silicon carbide cover plate.

[0012] Preferably, the working surface layer has several guide grooves processed along its length, the inner sidewalls of the guide grooves are inclined at a 15° angle, and the area between each guide groove is set with a grid-like texture.

[0013] Preferably, the working surface layer has a retaining edge, which is integrally formed with the working surface layer and has a rounded corner transition on its inner side. A metal molybdenum wire is inlaid on the top of the retaining edge.

[0014] Preferably, the edge connection structure includes a connecting protrusion and a connecting groove. The connecting protrusion is located on one side edge of the push plate body, has a trapezoidal structure, and its surface is provided with anti-slip texture. The connecting groove is located on the other side edge of the push plate body, matches the connecting protrusion, and has a trapezoidal groove structure. An elastic sealing gasket is provided in the connecting groove.

[0015] Preferably, the edge connection structure includes a boss and a groove, and is configured as a stepped connection structure with a convex-concave fit. The boss is located on one side edge of the push plate body, and its surface is provided with several parallel sealing grooves. The sealing groove has a built-in sealing ring. The groove is located on the other side edge of the push plate body, and its bottom has several raised strips corresponding to the sealing grooves. When adjacent push plate bodies are connected, the raised strips are embedded in the sealing grooves and squeeze the sealing rings to form a double seal.

[0016] This invention also proposes a method for preparing a composite silicon carbide pusher plate for industrial kilns, comprising the following steps:

[0017] S1. Base layer forming: Select silicon carbide material micro powder with a purity of ≥95%, and add 5% silicon powder as sintering aid. After mixing, add an appropriate amount of water to make a slurry, and then use isostatic pressing to form the blank. After forming, the blank is dried and then reinforced ribs are processed in the mold.

[0018] S2. Transition layer forming: Silicon carbide particles and metallic silicon powder are mixed in a 7:3 ratio, organic binder is added, and the mixture is stirred evenly. The evenly mixed material is then spread evenly on the surface of the base plate and compacted by vibration to form a composite plate with a tight bond to the base plate.

[0019] S3. Integral sintering: The composite green body is placed in an inert gas protected sintering furnace, heated to 1800-1900℃ and held for 3-4 hours, and then cooled to room temperature with the furnace to achieve diffusion bonding between the base layer and the transition layer.

[0020] S4. Working surface layer forming: Nano silicon carbide powder and carbon fiber are mixed in a 9:1 ratio, and 2% boron nitride is added as a lubricant to make a mixed powder. The composite powder is then bonded to the surface of the transition layer through a hot pressing sintering process to form a dense working surface layer.

[0021] S5. The edge connection structure on both sides of the push plate body is machined using a CNC machine tool;

[0022] S6. The working surface layer is subjected to grinding and anti-oxidation treatment, and a nano-silicon carbide coating is sprayed using plasma spraying equipment.

[0023] In summary, the present invention has the following beneficial effects: the three-layer composite structure combined with the design of reinforcing ribs not only improves the overall structural strength and meets the high load requirements of large industrial kilns, but also effectively reduces the internal stress caused by the difference in thermal expansion coefficients, avoiding the problem of cracks caused by thermal stress concentration at high temperatures, and exhibits excellent thermal shock resistance; the nano-silicon carbide-carbon fiber composite structure of the working surface layer combined with the nano-silicon carbide coating significantly improves wear resistance, extends service life, ensures the normal operation of the kiln, and improves the production efficiency of the kiln.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of a composite silicon carbide pusher plate for an industrial kiln according to an embodiment of the present invention.

[0026] Figure 2 This is a cross-sectional view of the base layer according to an embodiment of the present invention;

[0027] Figure 3 This is a back view of the base layer in an embodiment of the present invention;

[0028] Figure 4 This is a cross-sectional view of the working surface layer in an embodiment of the present invention;

[0029] Figure 5 This is a side view of the working surface layer according to an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the edge connection structure in embodiment 2 of the present invention;

[0031] Figure 7 This is a flowchart illustrating the steps of a method for preparing a composite silicon carbide pusher plate for an industrial kiln according to an embodiment of the present invention.

[0032] In the picture:

[0033] 1. Push plate body; 2. Base layer; 21. Reinforcing rib; 22. Heat dissipation channel; 23. Weight reduction cavity; 3. Transition layer; 4. Working surface layer; 41. Guide groove; 42. Edge retainer; 421. Rounded corner transition; 5. Boss; 51. Sealing groove; 6. Groove; 61. Raised strip. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0035] like Figure 1-6 As shown in this embodiment, a composite silicon carbide pusher plate for industrial kilns includes multiple pusher plate bodies 1. Adjacent pusher plate bodies 1 are detachably connected via an edge connection structure. The pusher plate body 1, from the inside out, comprises:

[0036] The base layer 2 is made of silicon carbide material and has several uniformly distributed reinforcing ribs 21 inside, which are in a grid structure.

[0037] Specifically, the reinforcing rib 21 is integrated with the base layer 2 using an integral molding process to enhance its resistance to bending.

[0038] Transition layer 3 is composed of silicon carbide particles and metallic silicon composite;

[0039] Specifically, the silicon carbide particles have a particle size of 50-100 μm, accounting for 70%-75%, while metallic silicon serves as a binder phase to fill the gaps. The transition layer 3 is connected to the base layer 2 via a gradient sintering process, with the sintering temperature controlled at 1800-1900℃. This creates a 5-10 μm diffusion bonding layer at the interface between the base layer 2 and the transition layer 3, effectively mitigating the difference in thermal expansion coefficients between the different materials (base layer 2 has a thermal expansion coefficient of 4.5 × 10⁻⁶). -6 / ℃, the coefficient of thermal expansion of transition layer 3 is 5.2×10. -6 / ℃), improving thermal shock resistance.

[0040] The working surface layer 4 is made of composite material of nano-silicon carbide and carbon fiber. Its outer surface is ground and then coated with an anti-oxidation film layer and a nano-silicon carbide coating.

[0041] Thus, the three-layer composite structure combined with the design of reinforcing rib 21 not only improves the overall structural strength and meets the high load requirements of large industrial kilns, but also effectively reduces the internal stress caused by the difference in thermal expansion coefficients, avoiding the problem of cracks caused by thermal stress concentration at high temperatures, and has excellent thermal shock resistance. The nano-silicon carbide-carbon fiber composite structure of the working surface layer 4 combined with the nano-silicon carbide coating significantly improves wear resistance, extends service life, ensures the normal operation of the kiln, and improves the production efficiency of the kiln.

[0042] Furthermore, such as Figure 2As shown, the base layer 2 has a heat dissipation channel 22 connected to an external cooling source. The heat dissipation channel 22 is serpentine in shape, extending to both ends of the pusher plate body 1. The cross-sectional shape of the heat dissipation channel 22 is circular, and its diameter is determined according to the size of the pusher plate body 1 and the heat dissipation requirements. During kiln operation, a cooling medium, such as cold air or cooling water, is introduced into the heat dissipation channel 22 through the external cooling source. The cooling medium flows within the heat dissipation channel 22, absorbing the heat generated by the high-temperature environment of the pusher plate body 1, and then flows out from the other end of the heat dissipation channel 22, carrying away the heat, thereby achieving effective heat dissipation for the pusher plate body 1. This not only reduces the temperature of the pusher plate body 1, but also makes the temperature distribution of the pusher plate body 1 more uniform, reduces the thermal stress caused by temperature gradients, and improves the service life of the pusher plate body 1.

[0043] The inner surface of the heat dissipation channel 22 can also be polished to make the roughness Ra≤1.6μm, thereby reducing air flow resistance.

[0044] Furthermore, such as Figure 3 As shown, a weight-reducing cavity 23 is set at each of the four corners of the bottom of the base layer 2. The opening of the weight-reducing cavity 23 is sealed with a detachable silicon carbide cover plate (which can be connected to the base layer 2 by four M6 ceramic screws for easy maintenance). Specifically, the working cavity is 8-10mm deep, square in cross-section with a side length of 30-40mm, and the cavity wall thickness is ≥5mm. This reduces the weight of the push plate body 1 while avoiding affecting the overall structural strength.

[0045] Preferably, such as Figure 4 As shown, the working surface layer 4 has several guide grooves 41 machined along its length. The inner wall of the guide groove 41 is inclined at a 15° angle to reduce the frictional resistance during material conveying. The area between each guide groove 41 is set with a grid-like texture to enhance the friction on the material and prevent slippage.

[0046] Furthermore, such as Figure 5 As shown, the working surface layer 4 has a retaining edge 42 at its edge. The retaining edge 42 is integrally formed with the working surface layer 4, and its inner side is machined with a rounded corner transition 421 to avoid scratching the material. A metal molybdenum wire is embedded in the top of the retaining edge 42. The high melting point (2620℃) of the molybdenum wire is used to improve the high-temperature wear resistance of the retaining edge 42.

[0047] In Example 1, the edge connection structure includes a connecting protrusion and a connecting groove (not shown in the figure). The connecting protrusion is located on one side edge of the push plate body 1, has a trapezoidal structure, and its surface is provided with anti-slip texture to increase the stability of the connection. The connecting groove is located on the other side edge of the push plate body 1, matches the connecting protrusion, and has a trapezoidal groove structure. An elastic sealing gasket is provided in the connecting groove. This ensures both the tightness of the connection and provides a buffering effect, reducing damage to the push plate body 1 caused by uneven force at the connection point.

[0048] In Example 2: Figure 6 As shown, the edge connection structure includes a boss 5 and a groove 6, configured as a stepped connection structure with a convex-concave fit. The boss 5 is located on one side edge of the push plate body 1, and its surface has several parallel sealing grooves 51. The sealing grooves 51 contain sealing rings. The groove 6 is located on the other side edge of the push plate body 1, and its bottom has several raised strips 61 corresponding to the sealing grooves 51. When adjacent push plate bodies 1 are connected, the raised strips 61 are embedded in the sealing grooves 51 to compress the sealing rings, forming a double seal. Specifically, the sealing ring is a high-temperature resistant expanding graphite sealing ring with a circular cross-section, which can expand and fill gaps at high temperatures.

[0049] It should be noted that the edge connection structure can also be other structures, depending on the specific situation; for example, the dovetail tenon-spring groove mechanical interlock. The specific structure can be referred to the existing structure, and will not be repeated in this article.

[0050] like Figure 7 As shown in the embodiments of the present invention, a method for preparing a composite silicon carbide pusher plate for industrial kilns is also proposed. This method, used to prepare the composite silicon carbide pusher plate for industrial kilns described in the above embodiments, includes the following steps:

[0051] S1. Base layer forming: Select silicon carbide material micro powder with a purity of ≥95%, and add 5% silicon powder as sintering aid. After mixing, add an appropriate amount of water to make a slurry, and then use isostatic pressing to form the blank. After forming, the blank is dried and then reinforced ribs 21 are processed in the mold.

[0052] Meanwhile, heat dissipation channels 22 and weight reduction cavities 23 are machined inside the mold.

[0053] S2. Transition layer forming: Silicon carbide particles and metallic silicon powder are mixed in a 7:3 ratio, organic binder is added, and the mixture is stirred evenly. The evenly mixed material is then spread evenly on the surface of the base plate and compacted by vibration to form a composite plate with a tight bond to the base plate.

[0054] S3. Integral sintering: The composite green body is placed in an inert gas protected sintering furnace, heated to 1800-1900℃ and held for 3-4 hours, and then cooled to room temperature with the furnace to achieve diffusion bonding between the base layer 2 and the transition layer 3.

[0055] S4. Working surface layer forming: Nano silicon carbide powder and carbon fiber are mixed in a 9:1 ratio, and 2% boron nitride is added as a lubricant to make a mixed powder. The composite powder is then bonded to the surface of the transition layer through a hot pressing sintering process to form a dense working surface layer.

[0056] S5. The edge connection structure on both sides of the push plate body is machined using a CNC machine tool;

[0057] S6. The working surface layer is subjected to grinding and anti-oxidation treatment, and a nano-silicon carbide coating is sprayed using plasma spraying equipment.

[0058] The derivation process of the beneficial effects of this preparation method is largely similar to the derivation process of the beneficial effects of the composite silicon carbide pusher plate used in industrial kilns, so it will not be repeated here.

[0059] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0063] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A composite silicon carbide pusher plate for industrial kilns, comprising multiple pusher plate bodies, characterized in that, The two adjacent push plate bodies are detachably connected by an edge connection structure, and the push plate bodies, from the inside to the outside, include: The base layer is made of silicon carbide material and has several evenly distributed reinforcing ribs inside, which are in a grid structure. The transition layer is composed of silicon carbide particles and metallic silicon. The working surface layer is made of composite material of nano-silicon carbide and carbon fiber. Its outer surface is ground and then coated with an anti-oxidation film layer and a nano-silicon carbide coating.

2. The composite silicon carbide pusher plate for industrial kilns according to claim 1, characterized in that, The base layer has a heat dissipation channel that connects to an external cooling source. The heat dissipation channel is distributed in a serpentine shape, with both ends extending to the two sides of the push plate body. The cross-sectional shape of the heat dissipation channel is circular, and its diameter is determined according to the size of the push plate body and the heat dissipation requirements.

3. The composite silicon carbide pusher plate for industrial kilns according to claim 2, characterized in that, A weight-reducing cavity is provided at each of the four corners of the bottom of the base layer, and the opening of the weight-reducing cavity is sealed with a detachable silicon carbide cover plate.

4. The composite silicon carbide pusher plate for industrial kilns according to claim 1, characterized in that, The working surface layer has several guide grooves machined along its length. The inner sidewalls of the guide grooves are inclined at a 15° angle, and the area between each guide groove is set with a grid-like texture.

5. The composite silicon carbide pusher plate for industrial kilns according to claim 4, characterized in that, The working surface layer has a retaining edge, which is integrally formed with the working surface layer and has a rounded corner transition on its inner side. A metal molybdenum wire is inlaid on the top of the retaining edge.

6. The composite silicon carbide pusher plate for industrial kilns according to claim 1, characterized in that, The edge connection structure includes a connecting protrusion and a connecting groove. The connecting protrusion is located on one side edge of the push plate body, has a trapezoidal structure, and its surface is provided with anti-slip texture. The connecting groove is located on the other side edge of the push plate body, matches the connecting protrusion, and has a trapezoidal groove structure. An elastic sealing gasket is provided in the connecting groove.

7. The composite silicon carbide pusher plate for industrial kilns according to claim 1, characterized in that, The edge connection structure includes a boss and a groove, and is configured as a stepped connection structure with a convex-concave fit. The boss is located on one side edge of the push plate body, and its surface is provided with several parallel sealing grooves. The sealing groove has a built-in sealing ring. The groove is located on the other side edge of the push plate body, and its bottom has several raised strips corresponding to the sealing grooves. When adjacent push plate bodies are connected, the raised strips are embedded in the sealing grooves and squeeze the sealing rings to form a double seal.

8. A method for preparing a composite silicon carbide pusher plate for industrial kilns, used to prepare the composite silicon carbide pusher plate for industrial kilns as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Base layer forming: Select silicon carbide material micro powder with a purity of ≥95%, and add 5% silicon powder as sintering aid. After mixing, add an appropriate amount of water to make a slurry, and then use isostatic pressing to form the slurry. After forming, the blank is dried and then reinforced ribs are processed in the mold. S2. Transition layer forming: Silicon carbide particles and metallic silicon powder are mixed in a ratio of 7:3, organic binder is added, and the mixture is stirred evenly. The evenly mixed material is then spread evenly on the surface of the base plate and compacted by vibration to form a composite plate with a tight bond to the base plate. S3. Integral sintering: The composite green body is placed in an inert gas protected sintering furnace, heated to 1800-1900℃ and held for 3-4 hours, and then cooled to room temperature with the furnace to achieve diffusion bonding between the base layer and the transition layer. S4. Working surface layer forming: Nano silicon carbide powder and carbon fiber are mixed in a ratio of 9:1, and 2% boron nitride is added as a lubricant to form a mixed powder. The composite powder is then bonded to the surface of the transition layer through a hot pressing sintering process to form a dense working surface layer. S5. The edge connection structure on both sides of the push plate body is machined using a CNC machine tool; S6. The working surface layer is subjected to grinding and anti-oxidation treatment, and a nano-silicon carbide coating is sprayed using plasma spraying equipment.

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