Preparation method of carbon-ceramic diversion trench inner layer material

Abstract

The invention discloses a preparation method of a carbon ceramic diversion trench inner layer material, and relates to the technical field of composite material preparation, the method comprises the following specific steps: S1, selecting a steel material as a diversion trench base material, and carrying out rust removal, cleaning, sand blasting roughening treatment and drying on the surface of the base material for later use; s2, the ceramic powder, a binder and a dispersing agent are mixed according to the proportion, a solvent is added, and ceramic slurry is prepared. The unique composite structure of the steel base material, the inner ceramic layer and the outer carbon-ceramic composite layer is adopted, the inner ceramic layer has excellent high-temperature resistance, wear resistance and corrosion resistance by means of the characteristics of a ceramic material, and the ceramic material has good heat resistance, wear resistance and corrosion resistance; the diversion trench can directly bear strong scouring and corrosion of high-temperature molten glass, reliable inner-layer protection is provided for the diversion trench, the outer-layer carbon-ceramic composite layer takes carbon fibers as a reinforcing phase, and the overall strength and deformation resistance of the diversion trench are remarkably improved due to high strength and high toughness of the carbon fibers; and the problems of deformation and cracking of the diversion trench under a high-temperature working condition are effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, specifically a method for preparing the inner layer material of a carbon-ceramic guide channel. Background Technology

[0002] In many industrial production fields, especially in the glass production process, the guide channel is a key piece of equipment for guiding the flow of molten glass. Its performance directly affects the stability of the entire production process and the quality of the product. The glass production environment is extremely harsh, and the guide channel must withstand the strong scouring, corrosion and frequent thermal shock of high-temperature molten glass for a long time. This places extremely high demands on the performance of the guide channel material. It not only needs to have excellent high-temperature resistance to withstand the high temperature of the molten glass without softening or being damaged, but also needs to have good wear resistance and corrosion resistance to resist the scouring and chemical erosion of the molten glass. At the same time, in order to ensure the stability and sealing of the molten glass flow, the material also needs to have sufficient strength and deformation resistance to prevent deformation or cracking at high temperatures.

[0003] In traditional glass production, most flow channels are made of pure steel. While steel possesses certain strength and toughness, meeting basic usage requirements at room temperature, its performance defects become apparent under the high-temperature conditions of glass production. First, steel has limited high-temperature resistance. When subjected to prolonged scouring by molten glass, it is prone to thermal deformation. This deformation alters the size and shape of the flow channel, affecting the flow path and flow rate of the molten glass, resulting in uneven distribution and severely impacting the stability of glass product quality. Second, steel is also prone to cracking at high temperatures. High temperatures alter the internal stress distribution of steel, and when the stress exceeds its tolerance limit, cracks form. These cracks not only reduce the sealing performance of the flow channel, leading to molten glass leakage, increasing production costs and safety hazards, but also further accelerate steel corrosion and damage, shortening the service life of the flow channel. Furthermore, due to the unstable performance of steel at high temperatures, frequent replacement of the flow channel is necessary, increasing downtime, reducing production efficiency, and significantly increasing production costs. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for preparing the inner layer material of a carbon-ceramic guide channel. This method involves pre-treating a steel substrate through rust removal, cleaning, and sandblasting to enhance the adhesion between the substrate surface and subsequent coatings. Then, ceramic powders such as alumina, zirconium oxide, or silicon carbide are selected and combined with binders and dispersants to form a ceramic slurry. This slurry is then uniformly coated onto the inner surface of the substrate using plasma spraying or flame spraying, forming a ceramic prefabricated layer with excellent high-temperature resistance, wear resistance, and corrosion resistance. Next, a carbon-ceramic composite layer is coated by mixing short-cut carbon fibers, ceramic powder, and a curing agent to form a carbon-ceramic coating, which is then coated onto the outer surface of the ceramic prefabricated layer. The high strength and toughness of the carbon fibers enhance the overall strength and deformation resistance of the guide channel. Finally, curing and sintering processes are performed to ensure a strong bond between the layers, resulting in a high-performance carbon-ceramic guide channel. This significantly extends the service life of the guide channel, reduces operating costs, and is suitable for high-temperature applications such as glass production, demonstrating broad application prospects and market value.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing an inner layer material of a carbon-ceramic flow channel, the method comprising the following specific steps:

[0006] S1: Select steel as the base material for the guide channel, and perform rust removal, cleaning, sandblasting roughening treatment on the surface of the base material, and dry it for later use;

[0007] S2: Mix ceramic powder, binder and dispersant in proportion, add solvent to prepare ceramic slurry, and use spraying process to uniformly coat the ceramic slurry onto the inner surface of the pretreated substrate to form a ceramic prefabricated layer.

[0008] S3: Mix carbon fiber, ceramic powder and curing agent, add solvent to make carbon ceramic coating, and apply carbon ceramic coating to the outer surface of ceramic prefabrication layer by brushing or spraying process to form carbon ceramic composite layer;

[0009] S4: Place the coated substrate in a curing oven and keep it warm to allow the ceramic preform layer and the carbon ceramic composite layer to initially cure.

[0010] S5: The cured substrate is transferred into a sintering furnace and heated under inert gas protection to cause the ceramic layer and carbon ceramic layer to undergo a sintering reaction to form a composite coating. After cooling to room temperature, a carbon ceramic guide channel is obtained.

[0011] Further, in step S1, mechanical rust removal is used to remove rust and oxide scale from the substrate surface. The oxide scale must be completely removed to avoid affecting coating adhesion. Then, the surface oil is cleaned with anhydrous ethanol, followed by sandblasting roughening treatment. 80-120 mesh white corundum abrasive is used for sandblasting, with the sandblasting pressure controlled at 0.4-0.6 MPa. Too low a pressure results in insufficient roughness, while too high a pressure can damage the substrate surface. The substrate surface roughness is to reach Ra 3.2-6.3 μm. After treatment, the substrate is placed in a 100-120℃ oven for drying for 1-2 hours. Too low a temperature results in incomplete drying, while too high a temperature can lead to surface oxidation. Surface moisture is also removed.

[0012] Furthermore, in step S2, 60-80 parts of ceramic powder, 5-15 parts of binder, 0.5-2 parts of dispersant and 10-25 parts of deionized water are weighed by weight and placed in a ball mill for ball milling and mixing for 2-4 hours to prepare a uniform ceramic slurry.

[0013] Furthermore, the ceramic powder is selected from one or more of alumina, zirconium oxide, or silicon carbide. Alumina has excellent high temperature resistance and wear resistance, zirconium oxide has good toughness, and silicon carbide has good thermal conductivity. The combined use can optimize the overall performance of the ceramic layer. The binder is selected from sodium silicate or aluminate cement to ensure the formability and bonding strength of the ceramic layer. The dispersant is selected from polycarboxylate dispersants to effectively prevent the ceramic powder from agglomerating.

[0014] Furthermore, in step S2, the ceramic slurry is uniformly coated onto the inner surface of the pretreated substrate using plasma spraying or flame spraying processes. Specifically:

[0015] For plasma spraying: the arc voltage is 60-80V and the current is 300-400A to ensure that the slurry is fully melted. The spraying distance is 80-120mm. If the distance is too close, the coating will be too thick and prone to cracking. If the distance is too far, the coating will have poor adhesion and form a 1-3mm ceramic prefabricated layer.

[0016] For flame spraying: oxygen pressure 0.5-0.7MPa, acetylene pressure 0.08-0.12MPa, control flame temperature 2000-2500℃ to ensure partial melting of ceramic powder, spraying distance 80-120mm. If the distance is too close, the coating will be too thick and prone to cracking; if the distance is too far, the coating adhesion will be poor, forming a 1-3mm ceramic preform layer.

[0017] Furthermore, in step S3, 5-15 parts by weight of short-cut carbon fiber, 50-70 parts of ceramic powder, 8-12 parts of epoxy resin curing agent, and 15-25 parts of solvent are weighed and mixed for 30-60 minutes to prepare a carbon-ceramic coating. The short-cut carbon fiber has a length of 0.5-2 mm. If it is too short, it cannot play a reinforcing role; if it is too long, it is prone to agglomeration. The diameter is 7-10 μm. The surface is modified with KH-550. The silane coupling agent can form chemical bonds between the carbon fiber and the ceramic powder, thereby improving the interfacial bonding force. The modification process is as follows: soaking in 1-2% KH-550 ethanol solution, stirring at 25-30℃ for 1-2 hours, and drying at 110-120℃ for 2-3 hours.

[0018] Furthermore, in step S4, the temperature is first increased to 80-100℃ at 5-10℃ / min for pre-curing, allowing the solvent to evaporate slowly and preventing the coating from bubbling, and the temperature is maintained for 1-1.5h; then the temperature is increased to 120-180℃ at 3-5℃ / min for complete curing, ensuring that the curing agent and the binder react fully to form a cross-linked structure, and the temperature is maintained for 2-4h. In addition, a slight positive pressure of 0.01-0.02MPa is maintained in the curing oven to prevent outside air from entering and causing the coating to oxidize.

[0019] Furthermore, in step S5, the cured substrate is transferred into a sintering furnace, and nitrogen or argon is introduced into the furnace as a protective gas at a flow rate of 0.5-1.5 L / min.

[0020] Furthermore, in step S5, the temperature is increased to 1000-1400℃ at a heating rate of 5-10℃ / min and held for 3-6 hours to allow the ceramic layer and carbon ceramic layer to undergo a sintering reaction, forming a dense composite coating. The specific steps are as follows:

[0021] Degreasing stage 400-500℃: Heat at 5-8℃ / min and hold for 1-2 hours to remove residual solvents and low molecular impurities in the coating and prevent impurities from volatilizing at high temperatures, which could cause pores in the coating.

[0022] Ceramification stage 800-1000℃: Increase the temperature at 3-5℃ / min and hold for 1.5-2.5h to promote the formation of sintering necks in ceramic powder and improve the density of the coating;

[0023] Densification stage 1000-1400℃: Heat up at 2-3℃ / min and hold for 3-6h to form a transition phase at the interface between the ceramic layer and the carbon ceramic layer, thereby improving the bonding strength of the three-layer structure.

[0024] Furnace cooling: The cooling rate is ≤10℃ / min until room temperature. Rapid cooling can easily generate thermal stress, which can cause the coating to crack and result in the finished product.

[0025] Compared with existing technologies, this method for preparing the inner layer material of a carbon-ceramic guide channel has the following advantages:

[0026] I. This invention employs a unique composite structure consisting of a steel substrate, an inner ceramic layer, and an outer carbon-ceramic composite layer. The inner ceramic layer, leveraging the inherent properties of ceramic materials, possesses excellent high-temperature resistance, wear resistance, and corrosion resistance, directly withstanding the intense scouring and corrosion of molten glass at high temperatures, providing reliable inner protection for the flow channel. The outer carbon-ceramic composite layer uses carbon fiber as a reinforcing phase. The high strength and toughness of carbon fiber significantly enhance the overall strength and deformation resistance of the flow channel, effectively preventing deformation and cracking problems that easily occur under high-temperature conditions. This fundamentally solves the technical defects of traditional steel flow channels, such as decreased sealing performance, increased risk of molten glass leakage, and short service life due to thermal deformation and cracking, greatly improving the performance of the flow channel in harsh high-temperature environments.

[0027] Second, this invention, through substrate sandblasting roughening treatment and reasonable coating formula design, ensures a firm bond between the ceramic inner layer, carbon-ceramic composite layer and steel substrate, making the coating less prone to peeling off, and further extending the service life of the guide channel. When applied to high-temperature conditions such as glass production, it can significantly extend the replacement cycle of the guide channel, reduce production interruption time caused by frequent guide channel replacement, improve production efficiency, and reduce the procurement and replacement costs of the guide channel, thereby effectively reducing the overall production cost and bringing significant economic benefits to enterprises.

[0028] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0030] Figure 1 A flowchart illustrating a method for preparing an inner layer material of a carbon-ceramic flow channel;

[0031] Figure 2 A flowchart illustrating a method for preparing an inner layer material of a carbon-ceramic flow channel;

[0032] Figure 3 This is a schematic diagram of a carbon ceramic guide channel. Detailed Implementation

[0033] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0034] This invention provides a method for preparing the inner layer material of a carbon-ceramic guide channel. The method involves pre-treating a steel substrate through rust removal, cleaning, and sandblasting to enhance the adhesion between the substrate surface and subsequent coatings. Then, ceramic powders such as alumina, zirconium oxide, or silicon carbide are selected and combined with binders and dispersants to form a ceramic slurry. This slurry is then uniformly coated onto the inner surface of the substrate using plasma spraying or flame spraying, forming a ceramic prefabricated layer with excellent high-temperature resistance, wear resistance, and corrosion resistance. Next, a carbon-ceramic composite layer is coated by mixing short-cut carbon fibers, ceramic powder, and a curing agent to form a carbon-ceramic coating, which is then applied to the outer surface of the ceramic prefabricated layer. The high strength and toughness of the carbon fibers enhance the overall strength and deformation resistance of the guide channel. Finally, curing and sintering processes are performed to ensure a strong bond between the layers, resulting in a high-performance carbon-ceramic guide channel. This significantly extends the service life of the guide channel, reduces operating costs, and is suitable for high-temperature applications such as glass production, demonstrating broad application prospects and market value.

[0035] like Figure 1 As shown, the present invention provides a method for preparing the inner layer material of a carbon-ceramic guide channel, comprising the following specific steps:

[0036] S1: Select steel as the base material for the guide channel, and perform rust removal, cleaning, sandblasting roughening treatment on the surface of the base material, and dry it for later use;

[0037] In one embodiment, Q235 steel with no scratches, dents, or other defects is selected as the primary material. The steel is 10mm thick and has a yield strength of 235MPa, suitable for the load-bearing requirements of conventional guide channels in glass factories. First, mechanical rust removal is performed using an electric wire brush at 1500r / min, following the steel's grain. Special attention is paid to cleaning edges and corners where rust easily accumulates, ensuring the rust removal depth is controlled to 0.2mm, until the steel's natural color is exposed and no oxide scale remains. Then, the rust-removed substrate is completely immersed in an ultrasonic cleaning tank containing anhydrous ethanol with a purity ≥99.7%. The ultrasonic power is set to 300W, and the cleaning time is 15 minutes per cycle. After two cleaning cycles, the substrate is removed and its surface is gently wiped with a clean, lint-free cloth to confirm the absence of oil stains. After testing, the residual oil on the surface was found to be ≤0.1mg / cm². Sandblasting was then performed to roughen the surface. 100-mesh white corundum abrasive with a Mohs hardness of 9.0 and uniform particle size without lumps was used. The inner surface of the substrate was treated with a sandblasting gun with an 8mm nozzle diameter, maintaining a sandblasting pressure of 0.5MPa and a distance of 180mm between the gun and the substrate. The gun was moved at a constant speed of 60mm / s to avoid repeated sandblasting in certain areas, which could thin the substrate surface. After roughening, residual abrasive particles were blown away with compressed air at a pressure of 0.2MPa. The substrate was then placed in a hot air oven at a temperature of 110℃ and a wind speed of 1.5m / s for 1.5 hours. After drying, a moisture meter was used to measure the moisture content at three different locations on the substrate to ensure that the surface moisture content was ≤0.5% before it was ready for use.

[0038] S2: Mix ceramic powder, binder and dispersant in proportion, add solvent to prepare ceramic slurry, and use spraying process to uniformly coat the ceramic slurry onto the inner surface of the pretreated substrate to form a ceramic prefabricated layer.

[0039] In one embodiment, an electronic balance is used for weighing. 70 parts by weight of alumina powder (5-10 μm particle size, 99.5% purity) are accurately weighed and dried in a 105℃ oven for 2 hours to remove moisture; 10 parts of sodium silicate (modulus 2.8) are pre-stirred to prevent clumping, and its bonding strength is measured to be ≥3 MPa; 1 part of polycarboxylate dispersant (SN-5040, solid content 35%); and 19 parts of deionized water (conductivity ≤10 μS / cm) are added. All raw materials are poured into a 5L alumina ball mill jar. Before ball milling, the jar wall is rinsed with water and then dried at 120℃ to remove impurities. Then, 8mm diameter alumina grinding balls are added, maintaining a ball-to-material ratio of 3:1. The jar is then secured to the ball mill, and the milling speed is set to 250 r / min for 3 hours. The mill is stopped every hour during this period, and the jar lid is opened to observe the slurry state to prevent grinding balls from becoming stuck. After ball milling, 1 The slurry was filtered using a 10-mesh nylon filter screen. During filtration, the slurry was gently stirred with a glass rod to assist filtration. The filter residue was collected and weighed to ensure that the filter screen residue was 0.3%. The solid content of the filtrate was measured to be 70% and the viscosity was 1500 mPa·s, which met the spraying requirements. Subsequently, an APS-3000 atmospheric plasma spraying equipment was used. Before spraying, a small sample of the same material was sprayed to check the coating thickness and uniformity. After confirming that the parameters were correct, the formal spraying began. The arc voltage was set to 70V, the current to 350A, the plasma gas to be a mixture of argon and hydrogen with a volume ratio of 9:1 and a flow rate of 40L / min, the spraying distance to 100mm, and the powder feeding rate to 8g / min. The substrate was fixed on a rotating worktable with a speed of 5r / min. The equipment was started and the coating was sprayed evenly along the inner surface of the substrate. During the process, the surface temperature of the coating was monitored in real time with an infrared thermometer to ensure that it did not exceed 200℃. Finally, a ceramic precast layer with a wet film thickness of 2mm was formed.

[0040] S3: Mix carbon fiber, ceramic powder and curing agent, add solvent to make carbon ceramic coating, and apply carbon ceramic coating to the outer surface of ceramic prefabrication layer by brushing or spraying process to form carbon ceramic composite layer;

[0041] In one embodiment, such as Figure 2As shown, the short-cut carbon fibers were first modified. The carbon fibers were 1 mm in length and 8 μm in diameter. A 1.5% KH-550 silane coupling agent ethanol solution was prepared in advance. The solution should be prepared and used immediately to avoid deterioration due to prolonged storage. The carbon fibers were completely immersed in the solution and stirred in a 28℃ constant temperature water bath for 2 hours. After being removed, they were dried in a 115℃ oven for 2.5 hours. After removal, Fourier transform infrared spectroscopy was used to detect that the surface hydroxyl content was increased by 18% compared with that before modification. 10 parts by weight of modified carbon fibers, 60 parts of alumina powder consistent with the inner layer of ceramic, 10 parts of T31 type amine curing agent with an active hydrogen equivalent of 90 g / eq, which was preheated to room temperature to avoid crystallization, and 20 parts of 99.5% pure acetone were weighed and poured into a GFJ-1.5 high-speed... In the mixing tank of the disperser, the speed was set to 800 r / min and stirred for 45 minutes. During this period, the machine was stopped every 15 minutes, and a small amount of coating was picked up with a glass rod for observation to ensure that there were no carbon fiber agglomerates and the coating did not separate. The final coating viscosity was measured to be 2500 mPa·s. When spraying, a GPQ6C high-pressure airless spraying equipment was used. The coating was first thoroughly stirred and uniform. The spray gun diameter was set to 1.8 mm, the spraying pressure to 0.4 MPa, and the spraying distance to 220 mm. The spray gun was kept perpendicular to the coating surface and applied to the outer surface of the ceramic precast layer in two coats. After the first coat was sprayed, it was allowed to stand at room temperature for 40 minutes. During this period, dust was avoided from falling on the coating surface. After the solvent had initially evaporated, the second coat was sprayed. Finally, a carbon-ceramic composite layer with a smooth surface, no bubbles and no drips was formed, with a wet film thickness of 3 mm.

[0042] S4: Place the coated substrate in a curing oven and keep it warm to allow the ceramic preform layer and the carbon ceramic composite layer to initially cure.

[0043] In one embodiment, the coated substrate is gently placed into an RXH-45 hot air curing oven, positioned in the center of the oven, away from the oven walls to prevent uneven oven wall temperatures from affecting the curing effect. A segmented curing process is performed: first, the temperature is increased from room temperature to 90°C at a rate of 5°C / min and held for 1.2 hours for pre-curing, allowing the acetone in the coating to evaporate slowly and preventing blistering. The oven temperature is recorded every 30 minutes during this period. After pre-curing, the temperature is increased to 150°C at a rate of 3°C / min and held for 3 hours to complete the full curing, ensuring that the curing agent is fully cross-linked with sodium silicate and epoxy resin. Compressed air is introduced into the oven during the curing process, and a slight positive pressure of 0.015MPa is maintained inside the oven using a pressure gauge to prevent outside air from entering and causing carbon fiber oxidation. After curing, the substrate is removed after the oven temperature naturally drops below 50°C. Five points are measured at different locations on the coating using a Rockwell hardness tester, and the average value is taken to ensure that the surface hardness reaches 52HRC.

[0044] S5: The cured substrate is transferred into a sintering furnace and heated under inert gas protection to cause the ceramic layer and carbon ceramic layer to undergo a sintering reaction to form a composite coating. After cooling to room temperature, a carbon ceramic guide channel is obtained.

[0045] In one embodiment, the cured substrate is carefully transferred into a GWL-1700 atmosphere sintering furnace. Nitrogen gas with a purity of 99.99% is first introduced into the furnace at a flow rate of 1 L / min. The inlet valve is closed every 10 minutes of purging, and an oxygen content detector is inserted into the furnace to measure the oxygen content. This purging process is repeated three times until the oxygen content is ≤0.1%. Then, segmented sintering begins: the temperature is increased to 450°C at a rate of 5°C / min and held for 1.5 hours for degreasing. During this time, the furnace top exhaust valve is opened to remove residual acetone and low-molecular-weight impurities produced by the decomposition of the curing agent. The process continues until no obvious smoke is observed at the exhaust port before proceeding to the next stage; the temperature is increased from 450°C at a rate of 3°C / min. The temperature is raised to 900℃ and held for 2 hours for ceramization, promoting the formation of a sintering neck in the alumina powder and increasing the density of the ceramic layer. Then, the temperature is raised to 1200℃ at a rate of 2℃ / min and held for 4 hours for densification, allowing the inner ceramic layer to form a silicon-oxygen bond transition phase at the interface with the carbon-ceramic composite layer, enhancing the interlayer bonding force. Throughout the sintering process, the heating rate and furnace temperature must be recorded regularly. If any abnormal heating occurs, such as a sudden increase or decrease in the rate, the heating should be stopped immediately and the equipment checked. After sintering, the heating device is turned off, and the furnace is cooled strictly according to the method of furnace cooling, with the cooling rate controlled at 8℃ / min. It is forbidden to open the furnace door to accelerate cooling. After the furnace temperature drops to room temperature of 25℃, the carbon-ceramic guide channel is removed to obtain the finished product.

[0046] During testing, three testing points were selected at the bottom and three at the side of the guide channel. The bonding strength was measured using the pull-out method, with an average value of 16.5 MPa. In the high-temperature stability test, the guide channel was fixed in a 1200℃ high-temperature furnace and kept at that temperature for 1000 hours before being removed. The deformation at different locations was measured using a laser diameter gauge, with the maximum deformation being only 0.4%. The wear resistance test was conducted using a wear testing machine with a load of 50 N and a rotation speed of 200 r / min. Compared with the traditional Q235 steel guide channel, the wear was reduced. Subsequently, the guide channel was installed in the glass melt guide section of a glass factory. Daily records showed that the glass melt temperature was between 1250-1300℃ and the flow rate was maintained at 5 t / h. During six months of continuous use, the guide channel showed no leakage and no surface peeling. Its service life was significantly extended compared to the traditional steel guide channel, fully meeting production requirements.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing the inner layer material of a carbon-ceramic guide channel, characterized in that, The method includes the following specific steps: S1: Select steel as the base material for the guide channel, and perform rust removal, cleaning, sandblasting roughening treatment on the surface of the base material, and dry it for later use; S2: Mix ceramic powder, binder and dispersant in proportion, add solvent to prepare ceramic slurry, and use spraying process to uniformly coat the ceramic slurry onto the inner surface of the pretreated substrate to form a ceramic prefabricated layer. S3: Mix carbon fiber, ceramic powder and curing agent, add solvent to make carbon ceramic coating, and apply carbon ceramic coating to the outer surface of ceramic prefabrication layer by brushing or spraying process to form carbon ceramic composite layer; S4: Place the coated substrate in a curing oven and keep it warm to allow the ceramic preform layer and the carbon ceramic composite layer to initially cure. S5: The cured substrate is transferred into a sintering furnace and heated under inert gas protection to cause the ceramic layer and carbon ceramic layer to undergo a sintering reaction to form a composite coating. After cooling to room temperature, a carbon ceramic guide channel is obtained.

2. The method for preparing the inner layer material of a carbon-ceramic guide channel according to claim 1, characterized in that, In step S1, rust and oxide scale on the substrate surface are removed by mechanical rust removal. Then, the surface oil is cleaned with anhydrous ethanol, followed by sandblasting roughening treatment. 80-120 mesh white corundum sand is used for sandblasting, and the sandblasting pressure is controlled at 0.4-0.6 MPa to make the surface roughness of the substrate reach Ra3.2-6.3 μm. After the treatment is completed, the substrate is placed in an oven at 100-120℃ to dry for 1-2 hours to remove surface moisture.

3. The method for preparing the inner layer material of a carbon-ceramic guide channel according to claim 1, characterized in that, In step S2, 60-80 parts of ceramic powder, 5-15 parts of binder, 0.5-2 parts of dispersant and 10-25 parts of deionized water are weighed by weight and put into a ball mill for ball milling and mixing for 2-4 hours to prepare a uniform ceramic slurry.

4. The method for preparing the inner layer material of a carbon-ceramic guide channel according to claim 3, characterized in that, The ceramic powder is selected from one or more composites of alumina, zirconium oxide, or silicon carbide; the binder is selected from sodium silicate or aluminate cement; and the dispersant is selected from polycarboxylate dispersants.

5. The method for preparing the inner layer material of a carbon-ceramic guide channel according to claim 1, characterized in that, In step S2, the ceramic slurry is uniformly coated onto the inner surface of the pretreated substrate using plasma spraying or flame spraying processes. Specifically: For plasma spraying: the arc voltage is 60-80V and the current is 300-400A to ensure that the slurry is fully melted. The spraying distance is 80-120mm. If the distance is too close, the coating will be too thick and prone to cracking. If the distance is too far, the coating will have poor adhesion and form a 1-3mm ceramic prefabricated layer. For flame spraying: oxygen pressure 0.5-0.7MPa, acetylene pressure 0.08-0.12MPa, control flame temperature 2000-2500℃ to ensure partial melting of ceramic powder, spraying distance 80-120mm. If the distance is too close, the coating will be too thick and prone to cracking; if the distance is too far, the coating adhesion will be poor, forming a 1-3mm ceramic preform layer.

6. The method for preparing the inner layer material of a carbon-ceramic guide channel according to claim 1, characterized in that, In step S3, 5-15 parts of short-cut carbon fiber, 50-70 parts of ceramic powder, 8-12 parts of epoxy resin curing agent and 15-25 parts of solvent are weighed according to the mass ratio, and stirred and mixed for 30-60 minutes to prepare carbon ceramic coating.

7. The method for preparing the inner layer material of a carbon-ceramic guide channel according to claim 1, characterized in that, In step S4, the temperature is increased to 80-100℃ at a rate of 5-10℃ / min and held for 1-1.5 hours; then the temperature is increased to 120-180℃ at a rate of 3-5℃ / min and held for 2-4 hours.

8. The method for preparing the inner layer material of a carbon-ceramic guide channel according to claim 1, characterized in that, In step S5, the cured substrate is transferred into a sintering furnace, and nitrogen or argon is introduced into the furnace as a protective gas at a flow rate of 0.5-1.5 L / min.

9. The method for preparing the inner layer material of a carbon-ceramic guide channel according to claim 1, characterized in that, In step S5, the temperature is increased to 1000-1400℃ at a heating rate of 5-10℃ / min and held for 3-6 hours to allow the ceramic layer and carbon ceramic layer to undergo a sintering reaction, forming a dense composite coating. The specific steps are as follows: Degreasing stage 400-500℃: Heat at 5-8℃ / min and hold for 1-2 hours to remove residual solvents and low molecular impurities in the coating and prevent impurities from volatilizing at high temperatures, which could cause pores in the coating. Ceramification stage 800-1000℃: Increase the temperature at 3-5℃ / min and hold for 1.5-2.5h to promote the formation of sintering necks in ceramic powder and improve the density of the coating; Densification stage 1000-1400℃: Heat up at 2-3℃ / min and hold for 3-6h to form a transition phase at the interface between the ceramic layer and the carbon ceramic layer, thereby improving the bonding strength of the three-layer structure. Furnace cooling: The cooling rate is ≤10℃ / min until room temperature. Rapid cooling can easily generate thermal stress, which can cause the coating to crack and result in the finished product.

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