A carbon fiber mesh reinforced aluminum carbon slide plate brick and a preparation method thereof

Abstract

The application relates to a carbon fiber net reinforced aluminum carbon slide plate brick and a preparation method thereof. The technical scheme is as follows: cutting square hole carbon fiber nets and short carbon fibers are respectively oxidized in an air atmosphere, and then are respectively immersed in a precursor solution, dried, and respectively obtained are pretreated carbon fiber nets and pretreated short carbon fibers. Then, white corundum fine powder, flake graphite, carbon black, silicon powder, active alumina powder, boron carbide powder and the pretreated short carbon fibers are mixed, and the pretreated powder is obtained. White corundum particles with a particle size greater than 1mm and less than or equal to 3mm, white corundum particles with a particle size greater than 0.075mm and less than or equal to 1mm, the pretreated powder and a thermosetting phenolic resin are uniformly mixed, the mixture is filled in a mold, 1-3 layers of the pretreated carbon fiber nets are uniformly arranged in the mixture in the mold, and the carbon fiber net reinforced aluminum carbon slide plate brick is prepared through the steps of molding, drying, curing and sintering. The product prepared by the application has excellent mechanical properties and thermal shock resistance.

Description

Technical Field

[0001] This invention belongs to the technical field of aluminum-carbon sliding plate bricks. Specifically, it relates to a carbon fiber mesh reinforced aluminum-carbon sliding plate brick and its preparation method. Background Technology

[0002] Sliding gates are crucial high-temperature components used in the continuous casting process of iron and steel metallurgy, serving functions such as controlling steel flow and protecting the casting. Alumina-carbon refractories are commonly used in sliding gates due to their high high-temperature strength and excellent thermal shock resistance. However, the continuous development of iron and steel smelting technology has placed higher demands on the sliding gate components and related materials, particularly regarding service life. The service life of alumina-carbon sliding gate bricks in sliding gates is related not only to their thermal shock resistance but also to their high-temperature mechanical properties, and the introduction of reinforcing phases often improves these properties.

[0003] While current methods for introducing reinforcing phases can improve the thermal shock resistance and high-temperature mechanical properties of alumina-carbon sliding plate bricks to varying degrees, they often have the following three shortcomings: 1. The size of the in-situ reinforcing phase and the introduced reinforcing body is often limited to the millimeter scale or even smaller, thus limiting the reinforcing effect; 2. To ensure ease of preparation, the introduced fiber reinforcement is often in a chopped form, but compared to other fiber introduction methods, the reinforcing effect of chopped fibers is relatively limited; 3. In the application scenario of sliding plate bricks for steelmaking, there are different performance requirements in different directions of the material—higher mechanical properties are required in the front direction impacted by molten steel, while the mechanical properties in the side direction are relatively lower due to the presence of the sliding plate steel hoop. However, materials prepared by previous methods are often near-isotropic, and the properties in each direction cannot be independently adjusted, making such materials not the optimal choice for applications. Examples are as follows:

[0004] Micro-scale reinforcing phases at the micrometer scale can be generated in situ inside the material by introducing additives, such as the patented technology "A nano-silicon in-situ generated ceramic phase reinforced aluminum-carbon slide plate and its preparation process" (CN201911225412.4). In this technology, the nano-silicon powder and silicon tetrachloride added react with other components at high temperature to generate in-situ ceramic phases such as silicon carbide and silicon nitride, which is beneficial to improving the high-temperature mechanical properties of the material. However, the scale of these in-situ ceramic phases is at the micrometer level, and the reinforcing effect they can produce is limited.

[0005] The patented technology, "An Aluminum-Carbon Slide Brick with Added Titanium-Iron Alloy and Its Production Method" (CN202210645829.1), utilizes titanium-iron alloy powder. In this technology, the titanium in the added titanium-iron alloy powder reacts with other components at high temperatures to form in-situ ceramic phases such as titanium carbonitride, which is beneficial for improving the material's high-temperature mechanical properties and thermal shock resistance. However, the size of these in-situ ceramic phases does not exceed the micrometer range, thus limiting their reinforcing effect. The size of the in-situ reinforcing phase in the aforementioned technology is limited to the micrometer scale, thus restricting the extent of material performance improvement. To achieve a greater improvement in performance, researchers have introduced various millimeter-scale high-temperature resistant fibers with excellent mechanical properties to reinforce the aluminum-carbon slide bricks on a larger scale.

[0006] For example, the patent technology "An alumina fiber reinforced aluminum-carbon slide plate and its preparation process" (CN202211043808.9) adds alumina fiber as a reinforcement, which is beneficial to improving the high-temperature mechanical properties and thermal shock resistance of the material. However, the reinforcement effect brought by the short-cut fiber is relatively limited, and a large amount of alumina fiber is needed to achieve a significant effect. This not only increases the cost but also increases the difficulty of preparation. Improper preparation process can lead to uneven dispersion of raw materials, making it difficult to realize the reinforcement effect of the fiber. The patent technology "A non-burnt aluminum-carbon slide plate with added carbon fiber and its preparation method" (CN202111153432.2) adds short-cut carbon fiber as a reinforcement. Although it is beneficial to improve the high-temperature mechanical properties and thermal shock resistance of the material, the short-cut carbon fiber used in this technology is too long and has insufficient compatibility with other raw materials. As a result, conventional preparation processes cannot achieve sufficient uniformity of the fiber used. In addition, the inherent shortcomings of the short-cut fiber reinforcement form itself limit the improvement of the material's mechanical properties and thermal shock resistance. Summary of the Invention

[0007] The present invention aims to overcome the technical defects of the prior art and provides a method for preparing a carbon fiber mesh reinforced aluminum-carbon sliding block containing a multi-level reinforcement system from the microscale to the macroscale. This method has low equipment requirements and moderate production costs. The carbon fiber mesh reinforced aluminum-carbon sliding block prepared not only has excellent thermal shock resistance and mechanical properties, but also allows for independent adjustment of mechanical properties in different directions.

[0008] To achieve the above objectives, the specific steps of the technical solution adopted by the present invention are as follows:

[0009] Step 1: Weave carbon fiber bundles into a plain weave to form a square-hole carbon fiber mesh with the same aperture size, wherein the side length of the square hole is 5-10mm; then cut the square-hole carbon fiber mesh into the shape of the skateboard brick forming surface to obtain the cut square-hole carbon fiber mesh.

[0010] The carbon fiber bundle has a C content greater than 93wt%, and the number of carbon fiber monofilaments contained in the carbon fiber bundle is one of 3K, 6K, and 12K.

[0011] Step 2: Place the cut square-hole carbon fiber mesh and chopped carbon fiber in an air atmosphere and oxidize them at 400-600℃ for 20-40 minutes to obtain pre-oxidized square-hole carbon fiber mesh and pre-oxidized chopped carbon fiber, respectively.

[0012] Step 3: Immerse the pre-oxidized square-hole carbon fiber mesh and the pre-oxidized chopped carbon fiber in the precursor solution for 1 to 3 hours; then dry them at 50 to 60°C for 24 to 48 hours to obtain the pretreated carbon fiber mesh and the pretreated chopped carbon fiber, respectively.

[0013] The precursor solution is a mixture of catalyst precursor and anhydrous ethanol, and the amount of catalyst precursor added is 0.1 to 0.3 wt% of the corresponding pre-oxidized square-hole carbon fiber mesh or pre-oxidized short-cut carbon fiber.

[0014] Step 4: Mix 65-71 wt% of white corundum fine powder, 2-3 wt% of flake graphite, 5-6 wt% of carbon black, 10-11 wt% of silicon powder, 10-11 wt% of activated alumina powder, 1-2 wt% of boron carbide powder, and 1-2 wt% of pretreated short-cut carbon fibers for 1-3 hours to obtain pretreated powder.

[0015] Step 5: Mix 40-46 wt% of white fused alumina particles with a particle size greater than 1 mm and less than or equal to 3 mm, 15-18 wt% of white fused alumina particles with a particle size greater than 0.075 mm and less than or equal to 1 mm, 34-36 wt% of pretreated powder, and 5-6 wt% of thermosetting phenolic resin evenly to obtain a mixture.

[0016] Step 6: Fill the bottom or middle of the mold with the mixture, and evenly place 1 to 3 layers of pretreated carbon fiber mesh perpendicular to the pressing direction. Each layer of pretreated carbon fiber mesh is filled with the mixture. When the number of pretreated carbon fiber mesh is greater than 1 layer, they are placed at an angle θ. Then, press and shape it under 100 to 150 MPa, dry it at 80 to 110°C for 12 to 24 hours, then cure it at 180 to 200°C for 18 to 24 hours, and finally fire it under coke and 1200 to 1400°C for 3 to 5 hours to obtain carbon fiber mesh reinforced aluminum carbon slide block.

[0017] The included angle θ is the in-plane included angle between two adjacent square holes of the fiber mesh, that is, the smallest included angle between the orthographic projections of the square holes of two adjacent carbon fiber meshes, θ = 0 to 45°; when θ is greater than 0° and less than or equal to 45°, each layer of carbon fiber mesh is placed in a deflected position; when θ = 0°, each layer of carbon fiber mesh is placed in parallel, with only the placement depth being different.

[0018] The chopped carbon fiber has a C content greater than 93 wt% and a length of 1–3 mm.

[0019] The catalyst precursor is one of ferric nitrate, cobalt nitrate, and nickel nitrate; wherein: the ferric nitrate has a purity greater than 98 wt%, the cobalt nitrate has a purity greater than 98 wt%, and the nickel nitrate has a purity greater than 98 wt%.

[0020] The activated alumina powder has an Al2O3 content greater than 99 wt% and a particle size of less than 10 μm.

[0021] The purity of the anhydrous ethanol is greater than 99 wt%.

[0022] The Al2O3 content of the white fused alumina is greater than 99 wt%; wherein the particle size of the fine white fused alumina powder is less than 0.075 mm, and the particle size of the white fused alumina particles is 0.075 to 3 mm.

[0023] The flake graphite has a C content greater than 95 wt% and a particle size less than 0.15 mm.

[0024] The carbon black has a C content greater than 95wt% and a particle size less than 25nm.

[0025] The silicon powder has a Si content greater than 98 wt% and a particle size less than 0.075 mm.

[0026] The boron carbide powder has a B4C content greater than 98 wt% and a particle size of less than 10 μm.

[0027] The residual carbon of the thermosetting phenolic resin is greater than 45 wt%.

[0028] The coke has a carbon content greater than 90 wt% and a particle size less than 1 mm.

[0029] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0030] 1. Because the preparation method involved in this invention only requires conventional methods such as weaving, cutting, heat treatment, mixing, and molding, the requirements for processing equipment are not high. Furthermore, the white corundum, activated alumina powder, catalyst precursor, anhydrous ethanol, flake graphite, carbon black, silicon powder, boron carbide powder, phenolic resin, and coke used in this invention are all conventional industrial raw materials, and the industrial production and processing technology of carbon fiber is quite mature, thus the raw material cost is moderate. Therefore, this invention has the advantages of low equipment requirements and moderate production costs.

[0031] 2. Because the surface pre-oxidation process and catalyst precursor loading process used in this invention can promote the reaction between carbon fibers and the silicon-containing phase inside the slide block during firing, and generate in-situ ceramic phases such as silicon carbide whiskers near the fiber surface, it can increase the bonding strength between carbon fibers and other components of the material and make the carbon fibers tightly "rooted" in the product. Therefore, it makes it more difficult for carbon fibers to separate from other components, so that the excellent mechanical properties of carbon fibers can be more fully utilized, and the carbon fiber mesh reinforced aluminum-carbon slide block can be more significantly reinforced, thus giving it excellent mechanical properties and thermal shock resistance.

[0032] 3. Since the fiber mesh reinforcement used in this invention has a significant positive reinforcement effect on the laminate (stronger than chopped fibers) but a less significant lateral reinforcement effect on the laminate, which is consistent with the application characteristics of steelmaking slide plates, applying carbon fiber mesh reinforcement to carbon fiber mesh reinforced aluminum-carbon slide plate bricks can give full play to its advantages while avoiding the negative impact of its inherent disadvantages. Compared with chopped carbon fibers, using carbon fiber mesh as reinforcement not only makes the mechanical properties and thermal shock resistance of carbon fiber mesh reinforced aluminum-carbon slide plate bricks more superior, but also increases the designability of performance. Unlike previous near-isotropic materials, the mechanical properties of carbon fiber mesh reinforced aluminum-carbon slide plate bricks in different directions can be independently adjusted.

[0033] 4. This invention, through the introduction of catalysts and multi-scale carbon fibers, not only regulates the in-situ generated phase structure at the nanoscale, such as silicon carbide nanowhiskers, carbon nanotubes, and carbon nanofibers; but also regulates the internal structure at the micrometer scale, such as micrometer-sized silicon carbide whiskers and chopped carbon fibers; and further regulates the internal structure at the millimeter, centimeter, and larger scales, such as macroscopic carbon fiber bundles (i.e., carbon fiber mesh). In other words, the carbon fiber mesh-reinforced aluminum-carbon sliding plate bricks prepared by this invention, in addition to the whisker-interwoven structure at the microscale, also possess different-scale carbon fiber reinforcement structures tightly bonded to other components at the mesoscopic and macroscopic scales. This constitutes a multi-scale reinforcement system, which enhances the mechanical properties and thermal shock resistance of the carbon fiber mesh-reinforced aluminum-carbon sliding plate bricks, and its effect is significantly better than that of single-scale reinforcement. Due to the combined effect of the above factors, the carbon fiber mesh-reinforced aluminum-carbon sliding plate bricks prepared by this invention have the advantages of high mechanical strength at both room temperature and high temperature, and high thermal shock resistance.

[0034] The alumina-carbon slide block brick for steelmaking prepared by this invention was tested and found to have the following properties: bulk density of 3.1–3.3 g / cm³; apparent porosity of 4–7%; compressive strength at room temperature of 320–370 MPa; flexural strength at room temperature of 70–80 MPa; and fracture toughness at room temperature of 4.0–6.0 MPa·m. 1 / 2The high-temperature flexural strength is 57-67 MPa; when the thermal shock resistance test is conducted using the water quenching method (maximum temperature 1100℃), the sample can withstand 12-15 cycles of rapid heating and cooling before visible cracks appear.

[0035] The test data are as follows: bulk density and apparent porosity were tested according to national standard GB / T 2997-2015; room temperature compressive strength was tested according to national standard GB / T 5072-2008; room temperature flexural strength was tested according to national standard GB / T 3001-2017; high temperature flexural strength was tested according to national standard GB / T 3002-2017; and thermal shock resistance was tested according to national standard GB / T 30873-2014.

[0036] Therefore, the present invention has the characteristics of moderate production cost and easy industrial production. The carbon fiber mesh reinforced aluminum carbon slide block prepared has excellent mechanical properties and thermal shock resistance, and the mechanical properties in different directions can be independently adjusted. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments, but this is not intended to limit the scope of protection thereof.

[0038] A carbon fiber mesh reinforced aluminum-carbon sliding plate brick and its preparation method. The steps of the preparation method described in this specific embodiment are as follows:

[0039] Step 1: Weave carbon fiber bundles into a plain weave to form a square-hole carbon fiber mesh with the same aperture size, wherein the side length of the square hole is 5-10mm; then cut the square-hole carbon fiber mesh into the shape of the skateboard brick forming surface to obtain the cut square-hole carbon fiber mesh.

[0040] The carbon fiber bundle has a C content greater than 93wt%, and the number of carbon fiber monofilaments contained in the carbon fiber bundle is one of 3K, 6K, and 12K.

[0041] Step 2: Place the cut square-hole carbon fiber mesh and chopped carbon fiber in an air atmosphere and oxidize them at 400-600℃ for 20-40 minutes to obtain pre-oxidized square-hole carbon fiber mesh and pre-oxidized chopped carbon fiber, respectively.

[0042] Step 3: Immerse the pre-oxidized square-hole carbon fiber mesh and the pre-oxidized chopped carbon fiber in the precursor solution for 1 to 3 hours; then dry them at 50 to 60°C for 24 to 48 hours to obtain the pretreated carbon fiber mesh and the pretreated chopped carbon fiber, respectively.

[0043] The precursor solution is a mixture of catalyst precursor and anhydrous ethanol, and the amount of catalyst precursor added is 0.1 to 0.3 wt% of the corresponding pre-oxidized square-hole carbon fiber mesh or pre-oxidized short-cut carbon fiber.

[0044] Step 4: Mix 65-71 wt% of white corundum fine powder, 2-3 wt% of flake graphite, 5-6 wt% of carbon black, 10-11 wt% of silicon powder, 10-11 wt% of activated alumina powder, 1-2 wt% of boron carbide powder, and 1-2 wt% of pretreated short-cut carbon fibers for 1-3 hours to obtain pretreated powder.

[0045] Step 5: Mix 40-46 wt% of white fused alumina particles with a particle size greater than 1 mm and less than or equal to 3 mm, 15-18 wt% of white fused alumina particles with a particle size greater than 0.075 mm and less than or equal to 1 mm, 34-36 wt% of the pretreated powder and 5-6 wt% of thermosetting phenolic resin evenly to obtain a mixture.

[0046] Step 6: Fill the bottom or middle of the mold with the mixture, and evenly place 1 to 3 layers of pretreated carbon fiber mesh perpendicular to the pressing direction. Each layer of pretreated carbon fiber mesh is filled with the mixture. When the number of pretreated carbon fiber mesh is greater than 1 layer, they are placed at an angle θ. Then, press and shape it under 100 to 150 MPa, dry it at 80 to 110°C for 12 to 24 hours, then cure it at 180 to 200°C for 18 to 24 hours, and finally fire it under coke and 1200 to 1400°C for 3 to 5 hours to obtain carbon fiber mesh reinforced aluminum carbon slide block.

[0047] The included angle θ is the in-plane included angle between two adjacent square holes of the fiber mesh, that is, the smallest included angle between the orthographic projections of the square holes of two adjacent carbon fiber meshes, θ = 0 to 45°; when θ is greater than 0° and less than or equal to 45°, each layer of carbon fiber mesh is placed in a deflected position; when θ = 0°, each layer of carbon fiber mesh is placed in parallel, with only the placement depth being different.

[0048] The chopped carbon fiber has a C content greater than 93 wt% and a length of 1–3 mm.

[0049] The catalyst precursor is one of ferric nitrate, cobalt nitrate, and nickel nitrate; wherein: the ferric nitrate has a purity greater than 98 wt%, the cobalt nitrate has a purity greater than 98 wt%, and the nickel nitrate has a purity greater than 98 wt%.

[0050] The residual carbon of the thermosetting phenolic resin is greater than 45 wt%.

[0051] In this specific implementation:

[0052] The activated alumina powder has an Al2O3 content greater than 99 wt% and a particle size of less than 10 μm.

[0053] The purity of the anhydrous ethanol is greater than 99 wt%.

[0054] The Al2O3 content of the white fused alumina is greater than 99 wt%; wherein the particle size of the fine white fused alumina powder is less than 0.075 mm, and the particle size of the white fused alumina particles is 0.075 to 3 mm.

[0055] The flake graphite has a C content greater than 95 wt% and a particle size less than 0.15 mm.

[0056] The carbon black has a C content greater than 95wt% and a particle size less than 25nm.

[0057] The silicon powder has a Si content greater than 98 wt% and a particle size less than 0.075 mm.

[0058] The boron carbide powder has a B4C content greater than 98 wt% and a particle size of less than 10 μm.

[0059] The coke has a carbon content greater than 90 wt% and a particle size less than 1 mm.

[0060] The details will not be repeated in the examples.

[0061] Example 1

[0062] A carbon fiber mesh reinforced aluminum-carbon sliding plate brick and its preparation method. The specific steps of the preparation method described in this embodiment are as follows:

[0063] Step 1: Weave the carbon fiber bundles into a plain weave to form a square-hole carbon fiber mesh with the same aperture size, wherein the side length of the square hole is 5mm; then cut the square-hole carbon fiber mesh into the shape of the skateboard brick forming surface, thus obtaining the cut square-hole carbon fiber mesh.

[0064] Step 2: Place the cut square-hole carbon fiber mesh and chopped carbon fiber in an air atmosphere and oxidize them at 400°C for 20 minutes to obtain pre-oxidized square-hole carbon fiber mesh and pre-oxidized chopped carbon fiber, respectively.

[0065] Step 3: Immerse the pre-oxidized square-hole carbon fiber mesh and the pre-oxidized chopped carbon fiber in the precursor solution for 1 hour; then dry them at 50°C for 24 hours to obtain the pretreated carbon fiber mesh and the pretreated chopped carbon fiber, respectively.

[0066] The precursor solution is a mixture of catalyst precursor and anhydrous ethanol, and the amount of catalyst precursor added is 0.1 wt% of the corresponding pre-oxidized square-hole carbon fiber mesh or pre-oxidized short-cut carbon fiber.

[0067] Step 4: Mix 71 wt% white corundum fine powder, 2 wt% flake graphite, 5 wt% carbon black, 10 wt% silicon powder, 10 wt% activated alumina powder, 1 wt% boron carbide powder and 1 wt% pretreated short-cut carbon fiber for 1 hour to obtain pretreated powder.

[0068] Step 5: Mix 46 wt% of white fused alumina particles with a particle size greater than 1 mm and less than or equal to 3 mm, 15 wt% of white fused alumina particles with a particle size greater than 0.075 mm and less than or equal to 1 mm, 34 wt% of the pretreated powder and 5 wt% of thermosetting phenolic resin evenly to obtain a mixture.

[0069] Step Six: Fill the center of the mold with the mixture, and place a layer of pretreated carbon fiber mesh perpendicular to the pressurization direction. The mixture is then filled on top of the pretreated carbon fiber mesh. The mold is then pressed at 100 MPa, dried at 80°C for 12 hours, cured at 180°C for 18 hours, and finally fired at 1200°C for 3 hours with buried coke to obtain carbon fiber mesh-reinforced aluminum-carbon sliding plate bricks.

[0070] In this embodiment:

[0071] The carbon fiber bundle has a C content of 94wt% and contains 3K carbon fiber monofilaments.

[0072] The chopped carbon fiber has a C content of 94wt% and a length of 1mm.

[0073] The catalyst precursor is ferric nitrate.

[0074] The residual carbon of the thermosetting phenolic resin is 46 wt%.

[0075] The alumina-carbon slide block for steelmaking prepared in this embodiment was tested and found to have a bulk density of 3.3 g / cm³. 3 The apparent porosity is 4%; the compressive strength at room temperature is 320 MPa; the flexural strength at room temperature is 70 MPa; and the fracture toughness at room temperature is 4.0 MPa·m. 1 / 2 The high-temperature flexural strength is 57 MPa; when the thermal shock resistance test is conducted using the water quenching method (maximum temperature 1100℃), the sample can withstand 12 cycles of rapid heating and cooling before visible cracks appear.

[0076] Example 2

[0077] A carbon fiber mesh reinforced aluminum-carbon sliding plate brick and its preparation method. The specific steps of the preparation method described in this embodiment are as follows:

[0078] Step 1: Weave carbon fiber bundles into a plain weave to form a square-hole carbon fiber mesh with the same aperture size, wherein the side length of the square hole is 7mm; then cut the square-hole carbon fiber mesh into the shape of the skateboard brick forming surface, thus obtaining the cut square-hole carbon fiber mesh.

[0079] Step 2: Place the cut square-hole carbon fiber mesh and chopped carbon fiber in an air atmosphere and oxidize them at 450°C for 30 minutes to obtain pre-oxidized square-hole carbon fiber mesh and pre-oxidized chopped carbon fiber, respectively.

[0080] Step 3: Immerse the pre-oxidized square-hole carbon fiber mesh and the pre-oxidized chopped carbon fiber in the precursor solution for 1 hour, and then dry them at 55°C for 36 hours to obtain the pretreated carbon fiber mesh and the pretreated chopped carbon fiber, respectively.

[0081] The precursor solution is a mixture of catalyst precursor and anhydrous ethanol, and the amount of catalyst precursor added is 0.2 wt% of the corresponding pre-oxidized square-hole carbon fiber mesh or pre-oxidized short-cut carbon fiber.

[0082] Step 4: Mix 69 wt% white corundum fine powder, 3 wt% flake graphite, 6 wt% carbon black, 10 wt% silicon powder, 10 wt% activated alumina powder, 1 wt% boron carbide powder and 1 wt% pretreated short-cut carbon fiber for 2 hours to obtain pretreated powder.

[0083] Step 5: Mix 44 wt% of white fused alumina particles with a particle size greater than 1 mm and less than or equal to 3 mm, 16 wt% of white fused alumina particles with a particle size greater than 0.075 mm and less than or equal to 1 mm, 34 wt% of the pretreated powder and 6 wt% of thermosetting phenolic resin evenly to obtain a mixture.

[0084] Step 6: Fill the bottom 1 / 3 of the mold with the mixture, and evenly place two layers of pretreated carbon fiber mesh perpendicular to the pressing direction. Each layer of pretreated carbon fiber mesh is filled with the mixture. When there are two layers of pretreated carbon fiber mesh, they are placed at an angle θ. Then, press and form it under 110 MPa, dry it at 90°C for 16 hours, then cure it at 190°C for 20 hours, and finally fire it at 1300°C for 3 hours with buried coke to obtain carbon fiber mesh reinforced aluminum carbon slide block.

[0085] The included angle θ is the in-plane included angle between the square holes of two adjacent fiber meshes, that is, the smallest included angle between the orthographic projections of the square holes of two adjacent carbon fiber meshes. In this embodiment, the included angle θ = 0°; the two layers of carbon fiber meshes are placed in parallel, with only the placement depth being different.

[0086] In this embodiment:

[0087] The carbon fiber bundle has a C content of 94wt% and contains 3K carbon fiber monofilaments.

[0088] The chopped carbon fiber has a C content of 94wt% and a length of 1mm.

[0089] The catalyst precursor is cobalt nitrate.

[0090] The residual carbon of the thermosetting phenolic resin is 47 wt%.

[0091] The alumina-carbon slide block for steelmaking prepared in this embodiment was tested and found to have a bulk density of 3.2 g / cm³. 3 The apparent porosity is 6%; the compressive strength at room temperature is 340 MPa; the flexural strength at room temperature is 72 MPa; and the fracture toughness at room temperature is 4.5 MPa·m. 1 / 2 The high-temperature flexural strength is 60 MPa; when the thermal shock resistance test is conducted using the water quenching method (maximum temperature 1100℃), the sample can withstand 13 cycles of rapid heating and cooling before visible cracks appear.

[0092] Example 3

[0093] A carbon fiber mesh reinforced aluminum-carbon sliding plate brick and its preparation method. The specific steps of the preparation method described in this embodiment are as follows:

[0094] Step 1: Weave the carbon fiber bundles into a plain weave to form a square-hole carbon fiber mesh with the same aperture size, wherein the side length of the square hole is 8mm; then cut the square-hole carbon fiber mesh into the shape of the skateboard brick forming surface, thus obtaining the cut square-hole carbon fiber mesh.

[0095] Step 2: Place the cut square-hole carbon fiber mesh and chopped carbon fiber in an air atmosphere and oxidize them at 500°C for 30 minutes to obtain pre-oxidized square-hole carbon fiber mesh and pre-oxidized chopped carbon fiber, respectively.

[0096] Step 3: Immerse the pre-oxidized square-hole carbon fiber mesh and the pre-oxidized chopped carbon fiber in the precursor solution for 2 hours, and then dry them at 55°C for 42 hours to obtain the pretreated carbon fiber mesh and the pretreated chopped carbon fiber, respectively.

[0097] The precursor solution is a mixture of catalyst precursor and anhydrous ethanol, and the amount of catalyst precursor added is 0.2 wt% of the corresponding pre-oxidized square-hole carbon fiber mesh or pre-oxidized short-cut carbon fiber.

[0098] Step 4: Mix 67wt% white corundum fine powder, 3wt% flake graphite, 6wt% carbon black, 11wt% silicon powder, 11wt% activated alumina powder, 1wt% boron carbide powder and 1wt% pretreated short-cut carbon fiber for 2 hours to obtain pretreated powder.

[0099] Step 5: Mix 42wt% of white fused alumina particles with a particle size greater than 1mm and less than or equal to 3mm, 17wt% of white fused alumina particles with a particle size greater than 0.075mm and less than or equal to 1mm, 35wt% of the pretreated powder and 6wt% of thermosetting phenolic resin evenly to obtain a mixture.

[0100] Step 6: Fill the bottom 1 / 3 of the mold with the mixture, and evenly place two layers of pretreated carbon fiber mesh perpendicular to the pressing direction. Each layer of pretreated carbon fiber mesh is filled with the mixture. When there are two layers of pretreated carbon fiber mesh, they are placed at an angle θ. Then, press and shape it under 130MPa, dry it at 100℃ for 18 hours, then cure it at 190℃ for 22 hours, and finally fire it at 1300℃ for 4 hours with buried coke to obtain carbon fiber mesh reinforced aluminum carbon slide block.

[0101] The included angle θ is the in-plane included angle between two adjacent square holes of the fiber mesh, that is, the smallest included angle between the orthographic projections of the square holes of two adjacent carbon fiber meshes. In this embodiment, the included angle θ = 20°; the two layers of carbon fiber mesh are placed in a deflected position.

[0102] In this embodiment:

[0103] The carbon fiber bundle has a C content of 95wt% and contains 6K carbon fiber monofilaments.

[0104] The chopped carbon fiber has a C content of 95wt% and a length of 2mm.

[0105] The catalyst precursor is cobalt nitrate.

[0106] The residual carbon of the thermosetting phenolic resin is 47 wt%.

[0107] The alumina-carbon slide block for steelmaking prepared in this embodiment was tested and found to have a bulk density of 3.2 g / cm³. 3 The apparent porosity is 6%; the compressive strength at room temperature is 350 MPa; the flexural strength at room temperature is 75 MPa; and the fracture toughness at room temperature is 5.0 MPa·m. 1 / 2 The high-temperature flexural strength is 62 MPa; when the thermal shock resistance test is conducted using the water quenching method (maximum temperature 1100℃), the sample can withstand 14 cycles of rapid heating and cooling before visible cracks appear.

[0108] Example 4

[0109] A carbon fiber mesh reinforced aluminum-carbon sliding plate brick and its preparation method. The specific steps of the preparation method described in this embodiment are as follows:

[0110] Step 1: Weave the carbon fiber bundles into a plain weave to form a square-hole carbon fiber mesh with the same aperture size, wherein the side length of the square hole is 10mm; then cut the square-hole carbon fiber mesh into the shape of the skateboard brick forming surface, thus obtaining the cut square-hole carbon fiber mesh.

[0111] Step 2: Place the cut square-hole carbon fiber mesh and chopped carbon fiber in an air atmosphere and oxidize them at 600°C for 40 minutes to obtain pre-oxidized square-hole carbon fiber mesh and pre-oxidized chopped carbon fiber, respectively.

[0112] Step 3: Immerse the pre-oxidized square-hole carbon fiber mesh and the pre-oxidized chopped carbon fiber in the precursor solution for 3 hours, and then dry them at 60°C for 48 hours to obtain the pretreated carbon fiber mesh and the pretreated chopped carbon fiber, respectively.

[0113] The precursor solution is a mixture of catalyst precursor and anhydrous ethanol, and the amount of catalyst precursor added is 0.3 wt% of the corresponding pre-oxidized square-hole carbon fiber mesh or pre-oxidized chopped carbon fiber.

[0114] Step 4: Mix 65wt% white corundum fine powder, 3wt% flake graphite, 6wt% carbon black, 11wt% silicon powder, 11wt% activated alumina powder, 2wt% boron carbide powder and 2wt% pretreated short-cut carbon fiber for 3 hours to obtain pretreated powder.

[0115] Step 5: Mix 40 wt% of white fused alumina particles with a particle size greater than 1 mm and less than or equal to 3 mm, 18 wt% of white fused alumina particles with a particle size greater than 0.075 mm and less than or equal to 1 mm, 36 wt% of the pretreated powder and 6 wt% of thermosetting phenolic resin evenly to obtain a mixture.

[0116] Step 6: Fill the bottom 1 / 4 of the mold with the mixture, and evenly place 3 layers of pretreated carbon fiber mesh perpendicular to the pressing direction. Each layer of pretreated carbon fiber mesh is filled with the mixture. When there are 3 layers of pretreated carbon fiber mesh, they are placed at an angle θ. Then, press and form it under 150MPa, dry it at 110℃ for 24 hours, then cure it at 200℃ for 24 hours, and finally fire it at 1400℃ for 5 hours with buried coke to obtain carbon fiber mesh reinforced aluminum carbon slide block.

[0117] The included angle θ is the in-plane included angle between two adjacent square holes of the fiber mesh, that is, the smallest included angle between the orthographic projections of two adjacent square holes of the carbon fiber mesh. In this embodiment, the included angle θ = 45°, and the three layers of carbon fiber mesh are placed in a deflected manner.

[0118] In this embodiment:

[0119] The carbon fiber bundle has a C content of 95wt% and contains 12K carbon fiber monofilaments.

[0120] The chopped carbon fiber has a C content of 95wt% and a length of 3mm.

[0121] The catalyst precursor is nickel nitrate.

[0122] The residual carbon of the thermosetting phenolic resin is 48 wt%.

[0123] The alumina-carbon slide block for steelmaking prepared in this embodiment was tested and found to have a bulk density of 3.1 g / cm³. 3 The apparent porosity is 7%; the compressive strength at room temperature is 370 MPa; the flexural strength at room temperature is 80 MPa; and the fracture toughness at room temperature is 6.0 MPa·m. 1 / 2 The high-temperature flexural strength is 67 MPa; when the thermal shock resistance test is conducted using the water quenching method (maximum temperature 1100℃), the sample can withstand 15 cycles of rapid heating and cooling before visible cracks appear.

[0124] This specific implementation method has the following advantages compared with the prior art:

[0125] 1. Since the preparation method described in this specific embodiment only requires conventional methods such as weaving, cutting, heat treatment, mixing, and molding, the requirements for processing equipment are not high. Furthermore, the white corundum, activated alumina powder, catalyst precursor, anhydrous ethanol, flake graphite, carbon black, silicon powder, boron carbide powder, phenolic resin, and coke used in this specific embodiment are all conventional industrial raw materials, and the industrial production and processing technology of carbon fiber is quite mature, thus the raw material cost is moderate. Therefore, this specific embodiment has the advantages of low equipment requirements and moderate production costs.

[0126] 2. Because the surface pre-oxidation process and catalyst precursor loading process used in this specific embodiment can promote the reaction between carbon fibers and the silicon-containing phase inside the slide block during firing, and generate in-situ ceramic phases such as silicon carbide whiskers near the fiber surface, it can increase the bonding strength between carbon fibers and other components of the material and make the carbon fibers tightly "rooted" in the product. Therefore, it is more difficult for the carbon fibers to separate from other components, so that the excellent mechanical properties of the carbon fibers can be more fully utilized, and the carbon fiber mesh reinforced aluminum-carbon slide block can be more significantly reinforced, thus giving it excellent mechanical properties and thermal shock resistance.

[0127] 3. Since the fiber mesh reinforcement used in this specific embodiment has the characteristics of significant positive reinforcement effect on the laminate (stronger than chopped fibers) but not significant lateral reinforcement effect on the laminate, which is consistent with the application characteristics of steelmaking slide plates, applying carbon fiber mesh reinforcement to carbon fiber mesh reinforced aluminum-carbon slide plate bricks can give full play to its advantages while avoiding the negative impact of its inherent disadvantages. Compared with chopped carbon fibers, using carbon fiber mesh as reinforcement not only makes the mechanical properties and thermal shock resistance of carbon fiber mesh reinforced aluminum-carbon slide plate bricks more superior, but also increases the designability of performance. Unlike previous near-isotropic materials, the mechanical properties of carbon fiber mesh reinforced aluminum-carbon slide plate bricks in different directions can be independently adjusted.

[0128] 4. This specific embodiment, through the introduction of catalysts and multi-scale carbon fibers, not only regulates the in-situ generated phase structure at the nanoscale, such as silicon carbide nanowhiskers, carbon nanotubes, and carbon nanofibers; but also regulates the internal structure at the micrometer scale, such as micrometer-sized silicon carbide whiskers and chopped carbon fibers; and further regulates the internal structure at the millimeter, centimeter, and larger scales, such as macroscopic carbon fiber bundles (i.e., carbon fiber mesh). In other words, the carbon fiber mesh-reinforced aluminum-carbon sliding plate brick prepared in this specific embodiment, in addition to the whisker interwoven structure at the microscale, also possesses different-scale carbon fiber reinforcement structures tightly bonded to other components at the mesoscopic and macroscopic scales. This constitutes a multi-scale reinforcement system, which enhances the mechanical properties and thermal shock resistance of the carbon fiber mesh-reinforced aluminum-carbon sliding plate brick, and its effect is significantly better than that of single-scale reinforcement. Due to the combined effect of the above-mentioned factors, the carbon fiber mesh-reinforced aluminum-carbon sliding plate brick prepared in this specific embodiment has the advantages of high mechanical strength at both room temperature and high temperature, and high thermal shock resistance.

[0129] The alumina-carbon slide block brick for steelmaking prepared according to this specific embodiment was tested and found to have the following properties: bulk density of 3.1–3.3 g / cm³; apparent porosity of 4–7%; compressive strength at room temperature of 320–370 MPa; flexural strength at room temperature of 70–80 MPa; and fracture toughness at room temperature of 4.0–6.0 MPa·m. 1 / 2 The high-temperature flexural strength is 57-67 MPa; when the thermal shock resistance test is conducted using the water quenching method (maximum temperature 1100℃), the sample can withstand 12-15 cycles of rapid heating and cooling before visible cracks appear.

[0130] The test data are as follows: bulk density and apparent porosity were tested according to national standard GB / T 2997-2015; room temperature compressive strength was tested according to national standard GB / T 5072-2008; room temperature flexural strength was tested according to national standard GB / T 3001-2017; high temperature flexural strength was tested according to national standard GB / T 3002-2017; and thermal shock resistance was tested according to national standard GB / T 30873-2014.

[0131] Therefore, this specific embodiment has the characteristics of moderate production cost and easy industrial production. The prepared carbon fiber mesh reinforced aluminum carbon slide block has excellent mechanical properties and thermal shock resistance, and the mechanical properties in different directions can be independently adjusted.

Claims

1. A method for preparing a carbon fiber mesh reinforced aluminum-carbon sliding block, characterized in that... The steps of the preparation method are as follows: Step 1: Weave carbon fiber bundles into a plain weave to form a square-hole carbon fiber mesh with the same aperture size, wherein the side length of the square hole is 5-10mm; then cut the square-hole carbon fiber mesh into the shape of the skateboard brick forming surface to obtain the cut square-hole carbon fiber mesh. The carbon fiber bundle has a C content greater than 93wt%, and the number of carbon fiber monofilaments contained in the carbon fiber bundle is one of 3K, 6K, and 12K. Step 2: Place the cut square-hole carbon fiber mesh and chopped carbon fiber in an air atmosphere and oxidize them at 400-600℃ for 20-40 minutes to obtain pre-oxidized square-hole carbon fiber mesh and pre-oxidized chopped carbon fiber, respectively. Step 3: Immerse the pre-oxidized square-hole carbon fiber mesh and the pre-oxidized chopped carbon fiber separately in the precursor solution for 1 to 3 hours. Then dry at 50-60℃ for 24-48 hours to obtain pretreated carbon fiber mesh and pretreated short-cut carbon fiber, respectively. The precursor solution is a mixture of catalyst precursor and anhydrous ethanol, and the amount of catalyst precursor added is 0.1 to 0.3 wt% of the corresponding pre-oxidized square-hole carbon fiber mesh or pre-oxidized short-cut carbon fiber. Step 4: Mix 65-71 wt% of white corundum fine powder, 2-3 wt% of flake graphite, 5-6 wt% of carbon black, 10-11 wt% of silicon powder, 10-11 wt% of activated alumina powder, 1-2 wt% of boron carbide powder and 1-2 wt% of pretreated short-cut carbon fiber for 1-3 hours to obtain pretreated powder. Step 5: Mix 40-46 wt% of white fused alumina particles with a particle size greater than 1 mm and less than or equal to 3 mm, 15-18 wt% of white fused alumina particles with a particle size greater than 0.075 mm and less than or equal to 1 mm, 34-36 wt% of pretreated powder and 5-6 wt% of thermosetting phenolic resin evenly to obtain a mixture. Step 6: Fill the bottom or middle of the mold with the mixture, and evenly place 1 to 3 layers of pretreated carbon fiber mesh perpendicular to the pressing direction. Each layer of pretreated carbon fiber mesh is filled with the mixture. When the number of pretreated carbon fiber mesh is greater than 1 layer, they are placed at an angle θ. Then, press and shape it under 100 to 150 MPa, dry it at 80 to 110°C for 12 to 24 hours, then cure it at 180 to 200°C for 18 to 24 hours, and finally fire it under coke and 1200 to 1400°C for 3 to 5 hours to obtain carbon fiber mesh reinforced aluminum carbon slide block. The included angle θ is the in-plane included angle between two adjacent square holes of the fiber mesh, that is, the smallest included angle between the orthographic projections of two adjacent square holes of the carbon fiber mesh, θ = 0 to 45°; when θ is greater than 0° and less than or equal to 45°, each layer of carbon fiber mesh is placed in a deflected position; when θ = 0°, each layer of carbon fiber mesh is placed in parallel, with only the placement depth being different. The chopped carbon fiber has a C content greater than 93 wt% and a length of 1–3 mm. The catalyst precursor is one of ferric nitrate, cobalt nitrate, and nickel nitrate; wherein: the ferric nitrate has a purity greater than 98 wt%, the cobalt nitrate has a purity greater than 98 wt%, and the nickel nitrate has a purity greater than 98 wt%. The activated alumina powder has an Al2O3 content greater than 99 wt% and a particle size of less than 10 μm.

2. The method for preparing carbon fiber mesh reinforced aluminum-carbon sliding block according to claim 1, characterized in that... The purity of the anhydrous ethanol is greater than 99 wt%.

3. The method for preparing carbon fiber mesh reinforced aluminum-carbon sliding block according to claim 1, characterized in that... The Al2O3 content of the white fused alumina is greater than 99 wt%; wherein the particle size of the fine white fused alumina powder is less than 0.075 mm, and the particle size of the white fused alumina particles is 0.075 to 3 mm.

4. The method for preparing carbon fiber mesh reinforced aluminum-carbon sliding block according to claim 1, characterized in that... The flake graphite has a C content greater than 95 wt% and a particle size less than 0.15 mm.

5. The method for preparing carbon fiber mesh reinforced aluminum-carbon sliding block according to claim 1, characterized in that... The carbon black has a C content greater than 95wt% and a particle size less than 25nm.

6. The method for preparing carbon fiber mesh reinforced aluminum-carbon sliding block according to claim 1, characterized in that... The silicon powder has a Si content greater than 98 wt% and a particle size less than 0.075 mm.

7. The method for preparing carbon fiber mesh reinforced aluminum-carbon sliding block according to claim 1, characterized in that... The boron carbide powder has a B4C content greater than 98 wt% and a particle size of less than 10 μm.

8. The method for preparing carbon fiber mesh reinforced aluminum-carbon sliding block according to claim 1, characterized in that... The residual carbon of the thermosetting phenolic resin is greater than 45 wt%.

9. The method for preparing carbon fiber mesh reinforced aluminum-carbon sliding block according to claim 1, characterized in that... The coke has a carbon content greater than 90 wt% and a particle size less than 1 mm.

10. A carbon fiber mesh reinforced aluminum-carbon sliding plate brick, characterized in that... The carbon fiber mesh reinforced aluminum-carbon sliding plate brick is prepared by the method for preparing carbon fiber mesh reinforced aluminum-carbon sliding plate brick according to any one of claims 1 to 9.