Carbon / carbon composite material surface SiC coating and preparation method thereof
The preparation of SiC coating on the surface of the carbon/carbon composite material through laser directional energy deposition process solves the problem of oxidation of the material in a high-temperature oxygen atmosphere, and achieves the preparation of high-quality coatings and the improvement of material performance.
Patent Information
- Application Number
- CN202411326594.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-23
- Publication Date
- 2025-05-13
AI Technical Summary
The existing carbon/carbon composite materials will oxidize rapidly in an oxygen atmosphere above 400°C, resulting in insufficient corrosion and erosion resistance. The traditional coating preparation method is complex, costly, and easy to damage the matrix structure.
Using laser directional energy deposition technology, the Si powder and SiC powder are mixed and granulated to form Si-SiC composite powder. Using laser as the energy source, the powder is deposited on the surface of the carbon/carbon composite material under an argon carrier gas to form a high-quality SiC coating.
The efficient preparation of SiC coating on the surface of carbon/carbon composite materials is achieved, and the high-temperature oxidation resistance, wear resistance and structural strength of the material are improved. The process is simple and the cost is low, so it does not damage the matrix structure.
Smart Images
Figure CN119977627A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of additive manufacturing coatings, and specifically relates to a SiC coating on the surface of a carbon / carbon composite material and a preparation method thereof. Background Art
[0002] Carbon / carbon (C / C) composites have the advantages of low density, high specific strength, high specific modulus, high thermal conductivity, low expansion coefficient, excellent friction performance and thermal shock resistance, and are widely used in high-tech fields such as aviation, aerospace, metallurgy, nuclear energy, and solar energy. However, carbon / carbon composites will oxidize rapidly in an oxygen atmosphere above 400°C, which seriously restricts the application of this material. Solving the high-temperature oxidation problem of carbon / carbon composites and improving the corrosion and erosion resistance of this material at high temperatures have become the focus of research in the field of carbon / carbon composites. Si-SiC ceramics have good physical and chemical compatibility with the carbon / carbon composite matrix, and can generate SiO2 self-healing phase with low oxygen permeability in a high-temperature aerobic environment, making it a commonly used material system for thermal protection coatings of C / C composites.
[0003] Traditional preparation methods for carbon / carbon composite surface coatings include embedding method, slurry method, chemical vapor deposition method, etc. The embedding method is a method in which the matrix material is embedded in several solid mixed powders, and a series of diffusion and chemical reactions are caused between the mixed powders and the surface of the matrix material by heat treatment to generate a coating with a certain thickness. Reference 1 "A new method to improve the laser-ablation resistance of Si-SiC coating on C / C composites: Laser cladding, Liu Teng, Han-Hui Wang, Xiao-Hong, Wei Li, Xue-Min Yin, He-Jun Li. Journal of the European Ceramic Society, 2022, 42(14):6425-6434." Silicon carbide coating was prepared by embedding on the surface of C / C composite material, and the coating sample was subjected to a three-point bending test. Compared with the uncoated C / C composite material, the flexural strength (46.57 MPa) and flexural modulus (6.53 GPa) of the embedded silicon carbide coating sample decreased by 59.67% and 59.35%, respectively, indicating that the matrix was severely damaged during the embedding process. The slurry method is to first process the coating material into a powder that meets the specified requirements, mix it with a solvent to form a slurry, and then fully stir it with a certain dispersant and binder, and evenly apply it to the substrate surface in the form of a slurry. Finally, the sample is heat-treated in a high-temperature inert atmosphere to obtain a coating sample. Reference 2 "Preparation of Al-Si alloy anti-oxidation coating of carbon / carbon composite material by slurry method, Huang Min, Li Kezhi, Wang Yu, Thermal Processing Technology, 2010, 39(18): 87-89." Slurries with different Al and Si ratios are respectively applied to the surface of carbon / carbon composite material with silicon carbide inner coating, and heat-treated to obtain Al-Si alloy outer coating. During the oxidation process of the Al-Si alloy coating formed by diffusion treatment at 1500℃, the molten slurry is not completely spread on the sample surface, leaving large hole defects on the coating surface, and the coating is easy to fall off, which accelerates the oxidation of the substrate C / C.Chemical vapor deposition is a process in which compounds are introduced into a deposition furnace under certain temperature and pressure conditions to cause a series of physical and chemical changes on the surface of the substrate to form a solid film. Reference 3 "High-temperature oxidation behavior of CVD-SiC ceramic coating in wet oxygen and structural evolution of oxidation product: Experiment and first-principle calculations, Pengfei Zhang, YuleiZhang, Guohui Chen, Wenhan Gai, Jingan Kong. Applied Surface Science, 2021, 556: 149808" used chemical vapor deposition to prepare a SiC coating with a thickness of about 10 um on the surface of a C / C composite material. In a wet oxygen environment at 1500°C, a SiO2 oxide layer with self-healing properties was generated on the coating surface. After oxidation for 30 hours, the weight loss rate of the material was only 3.47%. However, the chemical vapor deposition coating preparation process requires a high oxygen content, the preparation process is complex, the preparation cost is high, the prepared coating has weak bonding strength, and it is difficult to resist thermal erosion of particles in a high temperature environment.
[0004] Therefore, there is an urgent need for a preparation technology that is simple in process and ensures coating quality without damaging the performance of C / C composite materials. Summary of the invention
[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a method for preparing a carbon / carbon composite SiC coating based on laser directional energy deposition and a preparation method thereof, using laser as an energy source, adopting a coaxial automatic powder feeding mode, and using argon as a carrier gas to transport the deposited powder to the carbon / carbon composite substrate, and obtaining the desired coating by melting and solidifying the deposited powder.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention discloses a method for preparing a SiC coating on the surface of a carbon / carbon composite material, comprising the following steps: Pre-treating the carbon / carbon composite material matrix for later use; Si powder and SiC powder are mixed to obtain mixed powder, PVA solution, deionized water and anhydrous ethanol are added to the mixed powder for ball milling, and then spray granulation is performed to obtain Si-SiC composite powder as a deposition powder material; Si-SiC composite powder is used as deposition powder material, laser directed energy deposition process parameters are set, and laser directed energy deposition coating is performed on the substrate surface; Furthermore, the pretreatment is to grind the carbon / carbon composite material with a sand disk, put the processed carbon / carbon composite material matrix into anhydrous ethanol for ultrasonic cleaning, and dry it in an oven for standby use.
[0007] Furthermore, the particle size range of the Si powder is 20-90 μm; the particle size range of the SiC powder is 10-50 μm.
[0008] Furthermore, the mass ratio of the Si powder to the SiC powder is not less than 70%; the laser deposited powder is placed in an oven for drying before use; Furthermore, the mass ratio of the PVA solution, the mixed powder, deionized water and anhydrous ethanol is 4:4:1:1.
[0009] Furthermore, the mass concentration of the PVA solution is not less than 3%, and the ball milling time is not less than 6 hours.
[0010] Furthermore, the laser directed energy deposition process parameters are as follows: the laser spot diameter is not less than 3.0 mm; the laser power is 200~400 W; the laser printing rate is 120~240 mm / min; the path spacing is 1.0~3.0 mm; the powder feeding gas flow rate is not less than 8 L / min; and the powder tray rotation speed is not less than 7 r / min.
[0011] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a method for preparing a SiC coating on the surface of a carbon / carbon composite material, and belongs to the technical field of additive manufacturing coatings. Si powder and SiC powder are mixed and ball-milled to obtain a deposited powder, and the powder is sent to a molten pool system formed by the action of the laser on the surface of the composite material using laser as an energy source and argon as a carrier gas, thereby forming a SiC coating. The SiC coating provides wear resistance and structural strength for the C / C composite material due to its high hardness, excellent thermal stability and good high-temperature strength. Its thermal expansion coefficient matching that of the substrate helps to reduce thermal stress and prevent cracking of the coating. The addition of Si can improve the oxidation resistance of the SiC coating by reacting with oxygen at high temperature to form a SiO2 layer, and at the same time improve the compatibility and bonding force between the coating and the C / C composite material matrix, thereby improving the high-temperature performance and durability of the overall structure. In the laser directional energy deposition process of the present invention, the combination of parameters has a significant impact on the coating quality. The process parameters such as laser power, scanning speed and path spacing play an important role in the morphology, organizational structure and performance of the deposited layer. The optimal combination of process parameters was explored through experiments, including the systematic adjustment and optimization of parameters such as laser power, scanning speed, powder feeding rate, and the evaluation of the microstructure, interface bonding and performance of the deposited layer, achieving high-quality coating deposition, improving preparation efficiency, and increasing powder utilization; The coating preparation process of the method has a small heat-affected zone, is easy to form, does not damage the structure and performance of the substrate, can accurately control the thickness and shape of the coating, and the formed coating has good bonding strength with the substrate. The invention has good development prospects and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is a cross-sectional SEM image of the carbon / carbon composite SiC coating prepared in Example 1 of the present invention; Figure 2 This is a cross-sectional SEM image of the carbon / carbon composite SiC coating prepared in Example 2 of the present invention; Figure 3 This is a cross-sectional SEM image of the carbon / carbon composite SiC coating prepared in Example 3 of the present invention; Figure 4 This is a cross-sectional SEM image of the carbon / carbon composite SiC coating prepared in Example 4 of the present invention; Figure 5 This is the XRD scanning spectrum of the carbon / carbon composite SiC coating prepared in Examples 1-4 of the present invention. DETAILED DESCRIPTION
[0013] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.
[0014] The theories or mechanisms described and disclosed in the present invention, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.
[0015] In the present invention, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be deemed to have included and specifically disclosed all possible secondary ranges and individual values within the range (including integers and fractions).
[0016] In the present invention, unless otherwise specified, “comprising”, “including”, “containing”, “having” or similar terms cover the meanings of “consisting of” and “mainly consisting of”, for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a”.
[0017] In the present invention, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.
[0018] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.
[0019] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.
[0020] Example 1 A method for preparing a carbon / carbon composite SiC coating based on laser directed energy deposition specifically comprises the following steps: Step 1: Cut the carbon / carbon composite material into samples of 10*10*5 mm, grind them with a sand disk, clean them with anhydrous ethanol by ultrasonic cleaning, and dry them in an oven for later use.
[0021] Step 2: Select Si powder with an average particle size of 50 μm and SiC powder with an average particle size of 20 μm, add PVA solution, deionized water and anhydrous ethanol to the two powders for ball milling for 6 h to obtain a uniformly mixed slurry; wherein the mass ratio of SiC powder to Si powder is 1:1, the PVA concentration is 3.0%, and the mass ratio of PVA solution: mixed powder: deionized water: anhydrous ethanol is 4:4:1:1; Step 3: pumping the slurry into a spray granulator, and obtaining Si-SiC composite powder with good fluidity as deposition powder after spray granulation; Step 4: Using laser as the energy source, adopting the coaxial automatic powder feeding mode, and using argon as the carrier gas to transport the powder to the surface of the carbon / carbon composite material matrix, under the control of the computer system, the laser head moves along the X or Y direction, and the SiC coating is finally obtained by melting and solidifying the deposited powder layer by layer.
[0022] The laser power is 400 W, the powder feeding gas flow rate is 8 L / min, the powder disk rotation rate is 8 r / min, the laser printing rate is 120 mm / min, the laser spot diameter is 3 mm, the path spacing is 1 mm, the shielding gas flow rate is 10 L / min, and printing begins. After printing, a layer of deposited SiC coating is obtained on the surface of the carbon / carbon composite material substrate.
[0023] Figure 1 This is a cross-sectional SEM image of the carbon / carbon composite SiC coating prepared in Example 1. It can be seen that the coating is well bonded to the substrate, the coating is dense and has no defects, and the coating thickness is 200-220 um.
[0024] Example 2 The preparation method of the carbon / carbon composite SiC coating prepared by laser directed energy deposition specifically comprises the following steps: Step 1: Cut the carbon / carbon composite material into samples of 10*10*5 mm, grind them with a sand disk, clean them with anhydrous ethanol by ultrasonic cleaning, and dry them in an oven for later use.
[0025] Step 2: Select Si powder with an average particle size of 50 μm and SiC powder with an average particle size of 20 μm, add PVA solution, deionized water and anhydrous ethanol to the two powders for ball milling for 6 h to obtain a uniformly mixed slurry; wherein the mass ratio of SiC powder to Si powder is 4:3, the PVA concentration is 3.0%, and the mass ratio of PVA solution: mixed powder: deionized water: anhydrous ethanol is 4:4:1:1; Step 3: pumping the slurry into a spray granulator, and obtaining Si-SiC composite powder with good fluidity as deposition powder after spray granulation; Step 4: Using laser as the energy source, adopting the coaxial automatic powder feeding mode, and using argon as the carrier gas to transport the powder to the surface of the carbon / carbon composite material matrix, under the control of the computer system, the laser head moves along the X or Y direction, and the SiC coating is finally obtained by melting and solidifying the deposited powder layer by layer.
[0026] The laser power is 300 W, the powder feeding gas flow rate is 8 L / min, the powder disk rotation rate is 8 r / min, the laser printing rate is 120 mm / min, the laser spot diameter is 3 mm, the path spacing is 1.5 mm, the shielding gas flow rate is 10 L / min, and printing begins. After printing, a layer of deposited SiC coating is obtained on the surface of the carbon / carbon composite material substrate.
[0027] Figure 2 This is a cross-sectional SEM image of the carbon / carbon composite SiC coating prepared in Example 2. It can be seen that the coating is well bonded to the substrate, the coating is dense and has no defects, and the coating thickness is about 200 um.
[0028] Example 3 The preparation method of the carbon / carbon composite SiC coating prepared by laser directed energy deposition specifically comprises the following steps: Step 1: Cut the carbon / carbon composite material into samples of 10*10*5 mm, grind them with a sand disk, clean them with anhydrous ethanol by ultrasonic cleaning, and dry them in an oven for later use.
[0029] Step 2: Select Si powder with an average particle size of 50 μm and SiC powder with an average particle size of 20 μm, add PVA solution, deionized water and anhydrous ethanol to the two powders for ball milling for 6 h to obtain a uniformly mixed slurry; wherein the mass ratio of SiC powder to Si powder is 4:3, the PVA concentration is 3.0%, and the mass ratio of PVA solution: mixed powder: deionized water: anhydrous ethanol is 4:4:1:1; Step 3: pumping the slurry into a spray granulator, and obtaining Si-SiC composite powder with good fluidity as deposition powder after spray granulation; Step 4: Using laser as the energy source, adopting the coaxial automatic powder feeding mode, and using argon as the carrier gas to transport the powder to the surface of the carbon / carbon composite material matrix, under the control of the computer system, the laser head moves along the X or Y direction, and the SiC coating is finally obtained by melting and solidifying the deposited powder layer by layer.
[0030] The laser power is 200 W, the powder feeding gas flow rate is 9 L / min, the powder disk rotation rate is 8 r / min, the laser printing rate is 180 mm / min, the laser spot diameter is 4 mm, the path spacing is 1.5 mm, the shielding gas flow rate is 10 L / min, and printing begins. After printing, a layer of deposited SiC coating is obtained on the surface of the carbon / carbon composite material substrate.
[0031] Figure 3This is the cross-sectional SEM image of the carbon / carbon composite SiC coating prepared in Example 3. It can be seen that the coating is well bonded to the substrate and has good coating density, but poor flatness and a thin coating. The reason is that the coating surface suffers from severe consumption of low-melting-point Si due to excessive energy, and the overflow of gaseous Si leaves more pores on the coating surface. Larger pores will cause the material surface to be uneven and the coating thickness to decrease, with a thickness of 100-130um.
[0032] Example 4 A method for preparing a carbon / carbon composite SiC coating based on laser directed energy deposition specifically comprises the following steps: Step 1: Cut the carbon / carbon composite material into samples of 10*10*5 mm, grind them with a sand disk, clean them with anhydrous ethanol by ultrasonic cleaning, and dry them in an oven for later use.
[0033] Step 2: Select Si powder with an average particle size of 50 μm and SiC powder with an average particle size of 20 μm, add PVA solution, deionized water and anhydrous ethanol to the two powders for ball milling for 6 h to obtain a uniformly mixed slurry; wherein the mass ratio of SiC powder to Si powder is 4:3, the PVA concentration is 3.0%, and the mass ratio of PVA solution: mixed powder: deionized water: anhydrous ethanol is 4:4:1:1; Step 3: pumping the slurry into a spray granulator, and obtaining Si-SiC composite powder with good fluidity as deposition powder after spray granulation; Step 4: Using laser as the energy source, adopting the coaxial automatic powder feeding mode, and using argon as the carrier gas to transport the powder to the surface of the carbon / carbon composite material matrix, under the control of the computer system, the laser head moves along the X or Y direction, and the SiC coating is finally obtained by melting and solidifying the deposited powder layer by layer.
[0034] The laser power is 200 W, the powder feeding gas flow rate is 8 L / min, the powder disk rotation rate is 9 r / min, the laser printing rate is 240 mm / min, the laser spot diameter is 3 mm, the path spacing is 3 mm, the shielding gas flow rate is 10 L / min, and printing begins. After printing, a layer of deposited SiC coating is obtained on the surface of the carbon / carbon composite material substrate.
[0035] Figure 4This is the cross-sectional SEM image of the carbon / carbon composite material SiC coating prepared in Example 4. It can be seen that the coating has good density but poor flatness. Due to the low laser power and fast scanning speed, the laser energy acting on the material surface is low. As the temperature gradually decreases from the coating surface to the interface between the substrate and the coating, when preparing the coating, although the surface coating is relatively intact, the powder at the interface between the substrate and the coating cannot be completely melted, and holes appear inside the coating due to incomplete melting. Defects caused by incomplete melting, the coating thickness in this area will increase slightly, and seriously affect the bonding strength between the substrate and the coating, with a thickness of about 200um.
[0036] Figure 5 This is the XRD diagram of the carbon / carbon composite SiC coating prepared in Example 1-4, which further proves that the coating is a Si-SiC coating.
[0037] In summary, the present invention discloses a SiC coating on the surface of a carbon / carbon composite material prepared based on laser directional energy deposition and a preparation method thereof, which belongs to the technical field of additive manufacturing coatings. After Si powder and SiC powder are mixed and ball-milled to obtain a deposited powder, laser is used as an energy source, argon is used as a carrier gas, and the powder is sent to a molten pool system formed by the laser action on the surface of the composite material to form a SiC coating. The SiC coating provides wear resistance and structural strength for the C / C composite material due to its high hardness, excellent thermal stability and good high-temperature strength. Its thermal expansion coefficient matching that of the substrate helps to reduce thermal stress and prevent cracking of the coating. The addition of Si can improve the oxidation resistance of the SiC coating by reacting with oxygen at high temperature to form a SiO2 layer, and at the same time improve the compatibility and bonding force between the coating and the C / C composite matrix, thereby improving the high-temperature performance and durability of the overall structure. In the process of laser directional energy deposition of the present invention, the combination of parameters has a significant effect on the coating quality, and process parameters such as laser power, scanning speed and path spacing play an important role in the morphology, organizational structure and performance of the deposited layer. The optimal combination of process parameters was explored through experiments, including the systematic adjustment and optimization of parameters such as laser power, scanning speed, powder feeding rate, and the evaluation of the microstructure, interface bonding, and performance of the deposited layer, thus achieving high-quality coating deposition, improving preparation efficiency, and increasing powder utilization. The coating preparation process described in this method has a small heat-affected zone, is easy to form, and does not damage the structure and performance of the substrate. The coating thickness and shape can be precisely controlled, and the formed coating has good bonding strength with the substrate. This invention has good development prospects and economic benefits.
[0038] The above contents are only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.
Claims
1. A method for preparing a SiC coating on the surface of a carbon / carbon composite material, characterized in that: The following steps are involved: The Si powder and the SiC powder are uniformly mixed to obtain a mixed powder, a PVA solution, deionized water and anhydrous ethanol are added to the mixed powder for ball milling, and then a Si-SiC composite powder is obtained by spray granulation; Si-SiC composite powder is used as deposition powder material, laser directed energy deposition process parameters are set, laser directed energy deposition is performed on the substrate surface, and SiC coating on the surface of carbon / carbon composite material is obtained.
2. The method for preparing SiC coating on the surface of carbon / carbon composite material according to claim 1, characterized in that: The surface of the substrate is polished with a sand disc before deposition, and the polished carbon / carbon composite substrate is ultrasonically cleaned in anhydrous ethanol and dried in an oven.
3. The method for preparing SiC coating on the surface of carbon / carbon composite material according to claim 1, characterized in that: The particle size range of the Si powder is 20-90 μm; the particle size range of the SiC powder is 10-50 μm.
4. The method for preparing SiC coating on the surface of carbon / carbon composite material according to claim 1, characterized in that: The mass ratio of Si powder to SiC powder is not less than 70%.
5. The method for preparing SiC coating on the surface of carbon / carbon composite material according to claim 1, characterized in that: The Si-SiC composite powder is a dry powder.
6. The method for preparing SiC coating on the surface of carbon / carbon composite material according to claim 1, characterized in that: The mass ratio of the PVA solution, the mixed powder, deionized water and anhydrous ethanol is 4:4:1:
1.
7. The method for preparing SiC coating on the surface of carbon / carbon composite material according to claim 1, characterized in that: The mass concentration of the PVA solution is not less than 3%, and the ball milling time is not less than 6 hours.
8. The method for preparing SiC coating on the surface of carbon / carbon composite material according to claim 1, characterized in that: The specific process parameters of laser directed energy deposition are as follows: the laser spot diameter is not less than 3.0 mm, the laser power is 200~400 W, the laser printing rate is 120~240 mm / min, the path spacing is 1.0~3.0 mm, the powder feeding gas flow rate is not less than 8 L / min, and the powder tray operation speed is not less than 8 r / min.
9. A SiC coating on the surface of a carbon / carbon composite material, characterized in that: The SiC coating on the surface of the carbon / carbon composite material is obtained by the preparation method of any one of claims 1 to 8.
10. Application of the method for preparing SiC coating on the surface of carbon / carbon composite material according to any one of claims 1 to 8, characterized in that: Used to repair carbon / carbon composite surfaces.