Carbon fiber surface in-situ synthesis porous carbide ceramic nano coating and preparation method thereof

Abstract

The invention discloses a preparation method of a carbon fiber surface in-situ synthesis porous carbide ceramic nano coating. The preparation method specifically comprises the following steps: step 1) cutting continuous carbon fibers; 2) adding phenolic resin into ethanol, and stirring to form a solution A; 3) adding a catalyst into the solution A, stirring until the catalyst is completely dissolved, and then adding a halogenating agent to obtain a solution B; 4) adding MO2 powder into the solution B to obtain a solution C; (5) immersing the carbon fibers treated in the step (1) into a solution C; (6) keeping the carbon fiber with the surface coated with the solution C in a straightened state, fixing the carbon fiber in the crucible, and then carrying out curing treatment; and (7) carrying out heat treatment on the carbon fiber which is cured in the step (6) and fixed with the surface coating C solution, and carrying out atmosphere protection by using argon. The method solves the problem of low interface bonding performance of fibers and a matrix in the carbon fiber composite material. The invention further discloses the carbon fiber surface in-situ synthesis porous carbide ceramic nano coating.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of carbide ceramic nano - coatings, and particularly relates to an in - situ self - generating porous carbide ceramic nano - coating on the surface of carbon fibers, and also relates to a preparation method of the in - situ self - generating porous carbide ceramic nano - coating on the surface of such carbon fibers. Background Art

[0002] Before preparing carbon fiber composites, surface modification of carbon fibers can effectively improve the smooth and inert surface of carbon fibers, enhance the interfacial bonding performance between carbon fibers and the matrix, and the mechanical properties of carbon fiber composites. Preparing a layer of porous carbide MC (M = Si, Ti, Zr, Hf) ceramic nano - coating on the surface of carbon fibers to form a carbon fiber - nano - coating multi - scale reinforcement can increase the surface roughness of carbon fibers, modify the surface of carbon fibers at the nanoscale, and improve the interfacial bonding performance between the matrix and carbon fibers. If the carbon fiber - porous carbide ceramic nano - coating multi - scale reinforcement structure is introduced into the composite material, the porous nano - coating can effectively reduce the interfacial fracture energy and form a mechanical fusing effect, constituting toughening and strengthening mechanisms such as crack deflection and fiber pull - out at different scales, which is expected to further improve the mechanical properties of carbon fiber composites and promote their applications in fields such as aerospace, military parts, and high - temperature working conditions.

[0003] At present, there are many methods for preparing ceramic nano-coatings on the surface of carbon fibers, including polymer impregnation pyrolysis method, plasma electrolysis method, chemical vapor reaction deposition method, etc. All these methods have certain defects. For example, in the article "Advanced nano-composite coatings of ZrB2 / ZrC / SiC on carbon fibers via eco-friendly precursor synthesis" by Patra et al., a ZrB2 / ZrC / SiC nano-coating was prepared on the surface of carbon fibers by the polymer impregnation pyrolysis method. The coating has a uniform thickness, no impurities such as oxides, strong adhesion to the fibers, and effectively improves the high-temperature oxidation resistance of carbon fibers. The phase composition of the nano-coating prepared by the polymer impregnation pyrolysis method is restricted by the composition design of the polymer precursor, and the polymer precursor is expensive, resulting in a high cost for this method. In the article "Microstructure, properties and formation mechanism of SiO2 / SiC nano-coating onto carbon fiber by non-electrode plasma electrolysis" by Bu et al., a non-crystalline SiO2 / SiC nano-coating with a thickness of about 80 nm was prepared on the surface of carbon fibers by the non-electrode plasma electrolysis method. The coating is dense and uniform, has good adhesion to the fibers, and effectively reduces the oxidation rate of the fibers in the range of 880 - 1250 °C. In the article "In-situ synthesized nano-porous titanium carbide coating on silicon carbide fibres using titanium tetrachloride vapour" by Yang et al., a porous nano-TiC coating was prepared on the surface of silicon carbide fibers by the chemical vapor reaction deposition method. The porosity of the TiC nano-coating effectively reduces the interfacial fracture energy and increases the crack deflection path, improves the load transfer ability of the interface, makes the composite material after matrix composite show fracture characteristics such as interface cracking and fiber pull-out, and the fracture process of the composite material is pseudo-plastic fracture. However, the preparation of porous TiC nano-coatings by the chemical vapor reaction deposition method has the disadvantages of complex equipment, long cycle and high cost, and is not suitable for large-scale production. Summary of the Invention

[0004] The first object of the present invention is to provide a method for preparing an in-situ self-generated porous carbide ceramic nano-coating on the surface of carbon fibers, which solves the problem of low interfacial bonding performance between fibers and matrix caused by the smooth surface of carbon fibers.

[0005] The second object of the present invention is to provide a porous carbide ceramic nano - coating in - situ grown on the surface of carbon fiber.

[0006] The first technical solution adopted by the present invention is a preparation method for a porous carbide ceramic nano - coating in - situ grown on the surface of carbon fiber, specifically as follows:

[0007] Step 1) Cut continuous carbon fibers, perform ultrasonic cleaning, and dry them for later use;

[0008] Step 2) Add phenolic resin to ethanol and stir to form solution A;

[0009] Step 3) Add a catalyst to solution A, and then add a halogenating agent to obtain solution B;

[0010] Step 4) Add MO2 powder to solution B to obtain solution C;

[0011] Step 5) Immerse the carbon fibers obtained in Step 1 into solution C;

[0012] Step 6) Fix the carbon fibers with solution C coated on their surfaces in a straight state in a crucible, and then perform curing treatment;

[0013] Step 7) Heat - treat the carbon fibers fixed with solution C coated on their surfaces after the curing treatment in Step 6, and use argon for atmosphere protection.

[0014] The features of the present invention also lie in:

[0015] In Step 1, cut the continuous carbon fibers into strips with a length of 8 cm - 12 cm; the time for ultrasonic cleaning treatment is 1 h - 2 h.

[0016] In Step 2, the mass ratio of phenolic resin to ethanol is 3 - 6:7.

[0017] In Step 3, the catalyst is NiNO3·6H2O; the halogenating agent is KCl;

[0018] The mass ratio of NiNO3·6H2O to phenolic resin is 1 - 6:100; the mass ratio of KCl to NiNO3·6H2O is 8 - 12:1.

[0019] In Step 4, the mass ratio of MO2 powder to phenolic resin is 60 - 210:72, and the MO2 powder is TiO2 powder, SiO2 powder, ZrO2 powder or HfO2 powder.

[0020] In Step 6, the curing process is as follows: First, keep it at 75°C - 85°C for 9.5 h - 10.5 h, then raise the temperature to 115°C - 125°C and keep it for 2.5 h - 3.5 h, then raise it to 145°C - 155°C and keep it for 0.5 h - 1.5 h, and finally raise it to 175°C - 185°C and keep it for 2.5 h - 3.5 h.

[0021] In Step 7, the heat treatment process is as follows: First, raise the temperature to 800°C - 850°C at a rate of 5°C / min to 8°C / min; then raise the temperature to 980°C - 1020°C at a heating rate of 0.3°C / min to 0.5°C / min, and then raise it to 1580°C - 1620°C at a rate of 1°C / min to 2°C / min and keep it for 100 min - 120 min; finally, lower the temperature to room temperature at a rate of 5°C / min to 8°C / min; during the heat treatment process, the pressure in the furnace is maintained between 0.01 MPa and 0.02 MPa.

[0022] The second technical solution adopted by the present invention is that a porous carbide ceramic nano - coating is in - situ grown on the surface of carbon fiber and is prepared by the above - mentioned method.

[0023] The beneficial effects of the present invention are as follows:

[0024] (1) The method of the present invention uses phenolic resin as the carbon source for the carbide MC (M = Si, Ti, Zr, Hf) ceramic nano - coating. After the resin is dissolved in ethanol, a sol with a relatively high viscosity is formed, which is more likely to adhere evenly to the surface of carbon fiber, providing a basis for the subsequent preparation of a carbon fiber multi - scale reinforcement uniformly covered with a nano - coating.

[0025] (2) The method of the present invention uses an in - situ carbothermal reduction method to prepare a porous carbide MC (M = Si, Ti, Zr, Hf) ceramic nano - coating on the surface of carbon fiber. By using phenolic resin as the carbon source, the glassy carbon generated by the phenolic resin after heat treatment has high reactivity and is more likely to react with the MO2 raw material to form a uniformly - shaped MC ceramic nano - coating. Moreover, by using the in - situ reaction method, the MO2 raw material can also undergo a carbothermal reduction reaction with the carbon on the surface of the carbon fiber, and under the action of a catalyst and a halogenating agent, an MC ceramic nano - crystalline phase tightly connected to the fiber is formed, improving the bonding force between the ceramic nano - coating and the fiber.

[0026] (3) The method of the present invention dissolves all the raw materials in ethanol to form a uniform solution and impregnates the carbon fiber in it, laying a foundation for obtaining an in - situ grown porous nano - coating. After firing in a tube furnace, an in - situ grown carbon fiber - MC ceramic nano - coating multi - scale reinforcement is obtained, which can improve the interfacial performance between the carbon fiber and the matrix.

[0027] (4) The porous carbide MC (M = Si, Ti, Zr, Hf) ceramic nano - coating prepared by the method of the present invention can control the morphology of the nano - coating by changing the content of nickel nitrate hexahydrate.

[0028] (5) The solution impregnation method is a fiber surface modification method with simple operation, fast and effective, and low equipment requirements. The method of the present invention uses the solution impregnation method to prepare a porous TiC nano - coating on the surface of carbon fiber, which is expected to modify the fiber surface in a low - cost and easy - to - scale - up production method, and further improve the mechanical properties of carbon fiber composites. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is the low - magnification scanning electron microscope (SEM) photograph of the carbon fiber - porous TiC nano - coating multi - scale reinforcement prepared in Example 1 of the present invention;

[0030] Figure 2 is Figure 1 the high - magnification SEM photograph of the position A in

[0031] Figure 3 is Figure 2 the X - ray energy spectrum analysis (EDS) spectrum of the position B in

[0032] Figure 4 is the low - magnification SEM photograph of the carbon fiber - porous SiC nano - coating multi - scale reinforcement prepared in Example 2 of the present invention;

[0033] Figure 5 is Figure 4 the high - magnification SEM photograph of the position C in

[0034] Figure 6 is Figure 5 the EDS spectrum of the position D in DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0036] The present invention provides a method for preparing a porous carbide ceramic nano - coating in - situ on the surface of carbon fiber, which is specifically implemented according to the following steps:

[0037] Step 1) Cut the continuous carbon fiber, perform ultrasonic cleaning, and dry it for later use;

[0038] In Step 1, the continuous carbon fiber is cut into strips with a length of 8 cm - 12 cm; the time for ultrasonic cleaning treatment is 1 h - 2 h.

[0039] Step 2) Add phenolic resin to ethanol, and form solution A after magnetic stirring;

[0040] In Step 2, the mass ratio of phenolic resin to ethanol is 3 - 6:7.

[0041] Step 3) Add a catalyst to Solution A, stir magnetically until completely dissolved, then add a halogenating agent and stir until completely dissolved to obtain Solution B;

[0042] In Step 3, the catalyst is NiNO3·6H2O; the halogenating agent is KCl; the mass ratio of NiNO3·6H2O to phenolic resin is 1 - 6:100; the mass ratio of KCl to NiNO3·6H2O is 8 - 12:1.

[0043] Step 4) Add MO2 powder to Solution B and stir until completely dissolved to obtain Solution C;

[0044] In Step 4, the mass ratio of MO2 powder to phenolic resin is 60 - 210:72, and the MO2 powder is TiO2 powder, SiO2 powder, ZrO2 powder or HfO2 powder.

[0045] Step 5) Pour Solution C into a container, and immerse the carbon fiber obtained by treating in Step 1 in Solution C for 1 h - 3 h;

[0046] Step 6) Keep the carbon fiber with Solution C coated on its surface in a straightened state and fix it in a crucible, then put it into a drying oven for curing treatment;

[0047] In Step 6, the process of curing treatment is as follows: First, keep the temperature at 75°C - 85°C for 9.5 h - 10.5 h, then raise the temperature to 115°C - 125°C and keep it for 2.5 h - 3.5 h, then raise it to 145°C - 155°C and keep it for 0.5 h - 1.5 h, and finally raise it to 175°C - 185°C and keep it for 2.5 h - 3.5 h.

[0048] Step 7) Put the crucible with the carbon fiber having Solution C coated on its surface fixed in it after being cured in Step 6 into the corundum tube of a tube furnace for heat treatment, and use argon for atmosphere protection.

[0049] In Step 7, the process of heat treatment is as follows: First, raise the temperature to 800°C - 850°C at a rate of 5°C / min - 8°C / min; then raise the temperature to 980°C - 1020°C at a heating rate of 0.3°C / min - 0.5°C / min, then raise it to 1580°C - 1620°C at a rate of 1°C / min - 2°C / min, and keep it for 100 min - 120 min; finally, lower the temperature to room temperature at a rate of 5°C / min - 8°C / min; during the heat treatment process, the pressure in the furnace is kept between 0.01 MPa and 0.02 MPa.

[0050] The present invention also provides a carbon fiber surface in-situ self - generating porous carbide ceramic nano - coating, which is prepared by the above - mentioned method.

[0051] Example 1

[0052] A preparation method of an in-situ grown porous TiC nanocoating on the surface of carbon fiber is specifically implemented according to the following steps:

[0053] Step 1) Cut the continuous carbon fiber into strips with a length of 10 cm, perform ultrasonic cleaning treatment for 1 h, and dry it for later use;

[0054] Step 2) Add phenolic resin to a certain amount of ethanol, and magnetically stir for a certain time to form solution A;

[0055] In step 2, the mass ratio of phenolic resin to ethanol is 5:7.

[0056] Step 3) Add a certain amount of catalyst NiNO3·6H2O to solution A, magnetically stir until completely dissolved, then add a certain amount of halogenating agent KCl, and stir until completely dissolved to obtain solution B;

[0057] In step 3, the mass ratio of NiNO3·6H2O to phenolic resin is 1:100, and the mass ratio of KCl to NiNO3·6H2O is 8:1.

[0058] Step 4) Add a certain amount of TiO2 powder to solution B, and stir until completely dissolved to obtain solution C;

[0059] In step 4, the mass ratio of TiO2 powder to phenolic resin is 80:72.

[0060] Step 5) Pour solution C into a container, immerse the carbon fiber treated in step 1 in solution C for 1 h and then take it out;

[0061] Step 6) Fix the carbon fiber with solution C coated on its surface in a straight state in a crucible, and then put it into a drying oven for curing;

[0062] In step 6, the curing procedure is: first keep warm at 80 °C for 10 h, then raise the temperature to 120 °C and keep warm for 3 h, then raise it to 150 °C and keep warm for 1 h, and finally raise it to 180 °C and keep warm for 3 h.

[0063] Step 7) Put the crucible into the corundum tube of a tube furnace for heat treatment, and introduce argon for atmosphere protection.

[0064] In step 7, the heat treatment process is: first, raise the temperature to 800 °C at a rate of 6 °C / min; then raise the temperature to 1000 °C at a heating rate of 0.4 °C / min, then raise it to 1600 °C at a rate of 1 °C / min, and keep warm for 110 min; finally, lower the temperature to room temperature at a rate of 4 °C / min.

[0065] In step 7, during the heat treatment process, the pressure in the furnace is maintained at 0.01 MPa.

[0066] From Figure 1 it can be seen that a uniformly covered coating is formed on the surface of the carbon fiber. From Figure 2 it can be seen that the coating is composed of interconnected nanorods. The coating is in a porous morphology, which can increase the roughness of the carbon fiber surface and provide more crack deflection paths; from Figure 3 it can be seen that the main constituent elements of the nanorods in the nanocoating are Ti and C. It is thus inferred that the nanorods are TiC, that is, a nanocoating composed of dispersed porous TiC crystal rods is formed on the fiber surface. The preparation of this carbon fiber-porous TiC nanocoating multi-scale reinforcement can effectively improve the interfacial bonding performance between the carbon fiber and the matrix, and solve the problem of low interfacial bonding performance between the fiber and the matrix in carbon fiber composites.

[0067] Example 2

[0068] A method for in-situ growth of a porous SiC nanocoating on the surface of carbon fiber is specifically implemented according to the following steps:

[0069] Step 1) Cut the continuous carbon fiber into strips with a length of 10 cm, carry out ultrasonic cleaning treatment for 0.5 h, and dry for later use;

[0070] Step 2) Add phenolic resin to a certain amount of ethanol, and magnetically stir for a certain time to form solution A;

[0071] In step 2, the mass ratio of phenolic resin to ethanol is 6:7.

[0072] Step 3) Add a certain amount of catalyst NiNO3·6H2O to solution A, magnetically stir until completely dissolved, and then add a certain amount of halogenating agent KCl, and stir until completely dissolved to obtain solution B;

[0073] In step 3, the mass ratio of NiNO3·6H2O to phenolic resin is 2:100, and the mass ratio of KCl to NiNO3·6H2O is 9:1.

[0074] Step 4) Add a certain amount of SiO2 powder to solution B, and stir until completely dissolved to obtain solution C;

[0075] In step 4, the mass ratio of SiO2 powder to phenolic resin is 60:72.

[0076] Step 5) Pour solution C into a container, immerse the carbon fiber treated in step 1 into solution C for 2 h and then take it out;

[0077] Step 6) Fix the carbon fiber with solution C coated on its surface in a straight state in a crucible, and then put it into a drying oven for curing;

[0078] In step 6, the curing procedure is as follows: First, keep it at 80 °C for 10 h, then raise the temperature to 120 °C and keep it for 3 h, then raise it to 150 °C and keep it for 1 h, and finally raise it to 180 °C and keep it for 3 h.

[0079] Step 7) Put the crucible into the corundum tube of the tube furnace for heat treatment, and introduce argon for atmosphere protection.

[0080] In step 7, the heat treatment process is as follows: First, raise the temperature to 810 °C at a rate of 7 °C / min; then raise the temperature to 1010 °C at a heating rate of 0.4 °C / min, then raise it to 1620 °C at a rate of 2 °C / min, and keep it for 100 min; finally, cool it to room temperature at a rate of 5 °C / min.

[0081] In step 7, during the heat treatment process, the pressure in the furnace is maintained between 0.02 MPa.

[0082] From Figure 4 it can be seen that a uniformly covered coating is formed on the surface of the carbon fiber. From Figure 5 it can be seen that the coating is in a porous morphology and is composed of an interconnected nanowire network structure with a diameter of about 1 to several hundred nanometers. From Figure 6 it can be seen that the main constituent elements of the nanowires in the nanocoating are Si and C. From this, it is inferred that the nanowires are SiC, that is, a carbon fiber - multi - scale reinforcement porous SiC nanocoating is formed. This coating effectively improves the surface roughness of the carbon fiber and solves the problem of low interfacial bonding performance between the fiber and the matrix in the carbon fiber composite.

[0083] Example 3

[0084] A preparation method for in - situ growth of a porous ZrC nanocoating on the surface of carbon fiber is specifically implemented according to the following steps:

[0085] Step 1) Cut the continuous carbon fiber into strips with a length of 8 cm, carry out ultrasonic cleaning treatment for 1 h, and dry it for later use;

[0086] Step 2) Add phenolic resin to a certain amount of ethanol, and magnetically stir for a certain time to form solution A;

[0087] In step 2, the mass ratio of phenolic resin to ethanol is 1:7.

[0088] Step 3) Add a certain amount of catalyst NiNO3·6H2O to solution A, magnetically stir until it is completely dissolved, then add a certain amount of halogenating agent KCl, and stir until it is completely dissolved to obtain solution B;

[0089] In Step 3, the mass ratio of NiNO3·6H2O to phenolic resin is 1:100, and the mass ratio of KCl to NiNO3·6H2O is 8:1.

[0090] Step 4) Add a certain amount of ZrO2 powder to Solution B, and stir until it is completely dissolved to obtain Solution C;

[0091] In Step 4, the mass ratio of ZrO2 powder to phenolic resin is 60:72.

[0092] Step 5) Pour Solution C into a container, immerse the carbon fiber obtained in Step 1 in Solution C for 3 h, and then take it out;

[0093] Step 6) Fix the carbon fiber with Solution C coated on its surface in a straight state in a crucible, and then put it into a drying oven for curing;

[0094] In Step 6, the curing procedure is as follows: First, keep it at 75 °C for 9.5 h, then raise the temperature to 115 °C and keep it for 2.5 h, then raise it to 145 °C and keep it for 0.5 h, and finally raise it to 175 °C and keep it for 2.5 h.

[0095] Step 7) Place the crucible in the corundum tube of a tube furnace for heat treatment, and introduce argon for atmosphere protection.

[0096] In Step 7, the heat treatment process is as follows: First, raise the temperature to 850 °C at a rate of 5 °C / min; then raise the temperature to 980 °C at a heating rate of 0.3 °C / min, and then raise it to 1580 °C at a rate of 2 °C / min and keep it for 120 min; finally, lower the temperature to room temperature at a rate of 8 °C / min.

[0097] In Step 7, during the heat treatment process, the pressure in the furnace is maintained between 0.02 MPa.

[0098] Example 4

[0099] A method for preparing an in-situ grown porous HfC nanocoating on the surface of carbon fiber is specifically implemented according to the following steps:

[0100] Step 1) Cut the continuous carbon fiber into strips with a length of 12 cm, perform ultrasonic cleaning treatment for 2 h, and dry it for later use;

[0101] Step 2) Add phenolic resin to a certain amount of ethanol, and magnetically stir for a certain time to form Solution A;

[0102] In Step 2, the mass ratio of phenolic resin to ethanol is 6:7.

[0103] Step 3) Add a certain amount of catalyst NiNO3·6H2O to Solution A, magnetically stir until it is completely dissolved, and then add a certain amount of halogenating agent KCl, and stir until it is completely dissolved to obtain Solution B;

[0104] In Step 3, the mass ratio of NiNO3·6H2O to phenolic resin is 6:100, and the mass ratio of KCl to NiNO3·6H2O is 12:1.

[0105] Step 4) Add a certain amount of HfO2 powder to Solution B, and stir until completely dissolved to obtain Solution C;

[0106] In Step 4, the mass ratio of HfO2 powder to phenolic resin is 210:72.

[0107] Step 5) Pour Solution C into a container, immerse the carbon fiber obtained in Step 1 in Solution C for 3 h, and then take it out;

[0108] Step 6) Fix the carbon fiber with Solution C coated on its surface in a straight state in a crucible, and then put it into a drying oven for curing;

[0109] In Step 6, the curing procedure is as follows: First, keep it at 85 °C for 10.5 h, then raise the temperature to 125 °C and keep it for 3.5 h, then raise it to 155 °C and keep it for 1.5 h, and finally raise it to 185 °C and keep it for 3.5 h.

[0110] Step 7) Put the crucible into the corundum tube of a tube furnace for heat treatment, and introduce argon for atmosphere protection.

[0111] In Step 7, the heat treatment process is as follows: First, raise the temperature to 850 °C at a rate of 8 °C / min; then raise the temperature to 1020 °C at a heating rate of 0.5 °C / min, and then raise it to 1620 °C at a rate of 2 °C / min and keep it for 120 min; finally, lower the temperature to room temperature at a rate of 5 °C / min.

[0112] In Step 7, during the heat treatment process, the pressure in the furnace is kept between 0.01 MPa.

[0113] Example 5

[0114] A preparation method for an in-situ self-grown porous TiC nanocoating on the surface of carbon fiber is specifically implemented according to the following steps:

[0115] Step 1) Cut the continuous carbon fiber into strips with a length of 10 cm, perform ultrasonic cleaning treatment for 1.5 h, and dry it for later use;

[0116] Step 2) Add phenolic resin to a certain amount of ethanol, and magnetically stir for a certain time to form Solution A;

[0117] In Step 2, the mass ratio of phenolic resin to ethanol is 5:7.

[0118] Step 3) Add a certain amount of catalyst NiNO3·6H2O to solution A. After magnetic stirring until it is completely dissolved, add a certain amount of halogenating agent KCl, and stir until it is completely dissolved to obtain solution B;

[0119] In step 3, the mass ratio of NiNO3·6H2O to phenolic resin is 5:100, and the mass ratio of KCl to NiNO3·6H2O is 12:1.

[0120] Step 4) Add a certain amount of TiO2 powder to solution B, and stir until it is completely dissolved to obtain solution C;

[0121] In step 4, the mass ratio of TiO2 powder to phenolic resin is 80:72.

[0122] Step 5) Pour solution C into a container, immerse the carbon fiber obtained in step 1 in solution C for a certain time, and then take it out;

[0123] Step 6) Fix the carbon fiber with solution C coated on its surface in a straight state in a crucible, and then put it into a drying oven for curing;

[0124] In step 6, the curing procedure is as follows: First, keep it at 80°C for 10 h, then raise the temperature to 120°C and keep it for 3 h, then raise it to 150°C and keep it for 1 h, and finally raise it to 180°C and keep it for 3 h.

[0125] Step 7) Put the crucible into the corundum tube of a tube furnace for heat treatment, and introduce argon for atmosphere protection.

[0126] In step 7, the heat treatment process is as follows: First, raise the temperature to 820°C at a rate of 8°C / min; then raise the temperature to 1000°C at a heating rate of 0.5°C / min, then raise it to 1600°C at a rate of 1°C / min, and keep it for 100 min; finally, lower the temperature to room temperature at a rate of 6°C / min.

[0127] In step 7, during the heat treatment process, the pressure in the furnace is maintained between 0.02 MPa.

[0128] Example 6

[0129] A preparation method for an in-situ self-growing porous TiC nano-coating on the surface of carbon fiber is specifically implemented according to the following steps:

[0130] Step 1) Cut the continuous carbon fiber into strips with a length of 10 cm, perform ultrasonic cleaning treatment for 2 h, and dry it for later use;

[0131] Step 2) Add phenolic resin to a certain amount of ethanol, and form solution A after magnetic stirring for a certain time;

[0132] In step 2, the mass ratio of phenolic resin to ethanol is 6:7.

[0133] Step 3) Add a certain amount of catalyst NiNO3·6H2O to solution A. After magnetic stirring until completely dissolved, add a certain amount of halogenating agent KCl and stir until completely dissolved to obtain solution B;

[0134] In step 3, the mass ratio of NiNO3·6H2O to phenolic resin is 6:100, and the mass ratio of KCl to NiNO3·6H2O is 12:1.

[0135] Step 4) Add a certain amount of TiO2 powder to solution B and stir until completely dissolved to obtain solution C;

[0136] In step 4, the mass ratio of TiO2 powder to phenolic resin is 80:72.

[0137] Step 5) Pour solution C into a container, immerse the carbon fiber obtained in step 1 in solution C for a certain period of time, and then take it out;

[0138] Step 6) Fix the carbon fiber with solution C coated on its surface in a straight state in a crucible, and then put it into a drying oven for curing;

[0139] In step 6, the curing procedure is as follows: First, keep the temperature at 80°C for 10 h, then raise the temperature to 120°C and keep it for 3 h, then raise it to 150°C and keep it for 1 h, and finally raise it to 180°C and keep it for 3 h.

[0140] Step 7) Place the crucible into the corundum tube of a tubular furnace for heat treatment, and introduce argon for atmosphere protection.

[0141] In step 7, the heat treatment process is as follows: First, raise the temperature to 800°C at a rate of 6°C / min; then raise the temperature to 1000°C at a heating rate of 0.5°C / min, then raise it to 1600°C at a rate of 1°C / min, and keep it for 100 min; finally, lower the temperature to room temperature at a rate of 8°C / min.

[0142] In step 7, during the heat treatment process, the pressure in the furnace is maintained between 80.02 MPa.

Claims

1. Preparation method of in-situ self-growing porous carbide ceramic nano-coating on carbon fiber surface, characterized in that, Specifically: Step 1) Cut continuous carbon fibers, perform ultrasonic cleaning, and dry them for later use. Step 2) Add phenolic resin to ethanol and stir to form Solution A. Step 3) Add a catalyst to Solution A, and then add a halogenating agent to obtain Solution B. Step 4) Add MO2 powder to Solution B to obtain Solution C. Step 5) Immerse the carbon fibers treated in Step 1 into Solution C. Step 6) Fix the carbon fibers with Solution C coated on the surface in a straight state in a crucible, and then perform a curing treatment. Step 7) Heat-treat the carbon fibers fixed with Solution C coated on the surface after the curing treatment in Step 6, and use argon for atmosphere protection.

2. The preparation method of the in-situ self-growing porous carbide ceramic nano-coating on the carbon fiber surface according to claim 1, wherein In Step 1, cut the continuous carbon fibers into strips with a length of 8 cm - 12 cm; the time for ultrasonic cleaning treatment is 1 h - 2 h.

3. The preparation method of the in-situ self-growing porous carbide ceramic nano-coating on the carbon fiber surface according to claim 1, characterized in that, In Step 2, the mass ratio of phenolic resin to ethanol is 3 - 6:

7.

4. The preparation method of the in-situ self-growing porous carbide ceramic nano-coating on the carbon fiber surface according to claim 1, wherein, In Step 3, the catalyst is NiNO3·6H2O; the halogenating agent is KCl; the mass ratio of NiNO3·6H2O to phenolic resin is 1 - 6:100; the mass ratio of KCl to NiNO3·6H2O is 8 - 12:

1.

5. The preparation method of the in-situ self-growing porous carbide ceramic nano-coating on the carbon fiber surface according to claim 1, wherein, In Step 4, the mass ratio of MO2 powder to phenolic resin is 60 - 210:72, and the MO2 powder is TiO2 powder, SiO2 powder, ZrO2 powder, or HfO2 powder.

6. The preparation method of the in-situ self-generated porous carbide ceramic nano-coating on the carbon fiber surface according to claim 1, characterized in that In Step 6, the process of the curing treatment is: first keep warm at 75°C - 85°C for 9.5 h - 10.5 h, then raise the temperature to 115°C - 125°C and keep warm for 2.5 h - 3.5 h, then raise the temperature to 145°C - 155°C and keep warm for 0.5 h - 1.5 h, and finally raise the temperature to 175°C - 185°C and keep warm for 2.5 h - 3.5 h.

7. A method for preparing an in-situ self-generated porous carbide ceramic nano-coating on the surface of carbon fiber, characterized in that, In Step 7, the heat treatment process is: first raise the temperature to 800°C - 850°C at a rate of 5°C / min - 8°C / min; then raise the temperature to 980°C - 1020°C at a heating rate of 0.3°C / min - 0.5°C / min, then raise the temperature to 1580°C - 1620°C at a rate of 1°C / min - 2°C / min, and keep warm for 100 min - 120 min; finally, lower the temperature to room temperature at a rate of 5°C / min - 8°C / min; during the heat treatment process, the pressure in the furnace is maintained between 0.01 MPa and 0.02 MPa.

8. In-situ self-grown porous carbide ceramic nano-coating on the carbon fiber surface, characterized in that, Prepared by the method according to any one of claims 1 - 7.

Images