MAB phase coating coated carbon fiber and preparation method thereof

Abstract

A preparation method of the MAB phase coating coated carbon fiber comprises the following steps: sequentially treating the carbon fiber by adopting concentrated nitric acid, a sensitizing solution and an activating solution, soaking the treated carbon fiber in a chemical plating solution for plating, sequentially cleaning and drying the plated carbon fiber, then heating to 700-1200 DEG C in an inert atmosphere, and carrying out heat treatment for at least 0.5 h, so as to obtain the MAB phase coating coated carbon fiber. The MAB phase coating coated carbon fiber is obtained; the chemical plating solution comprises the following components: 21 g / L of cobalt sulfate, 5-23 g / L of sodium tungstate, 2-4 g / L of dimethylamino borane, 20-30 g / L of sodium citrate and deionized water as a solvent. The MAB-phase coating coated carbon fiber can effectively inhibit high-temperature oxidative damage of the carbon fiber, and the preparation method is simpler and more convenient to operate, lower in cost, shorter in period and convenient for industrial application.

Description

Technical Field

[0001] This invention relates to the field of carbon fiber surface modification technology, specifically to a method for preparing MAB phase coating coated carbon fiber. Background Technology

[0002] Carbon fiber, as a high-performance reinforcement, possesses outstanding properties such as high strength, high modulus, low coefficient of thermal expansion, and excellent flexibility. Therefore, carbon fiber can significantly improve the mechanical properties of composite materials and is widely used in the field of composite materials to enhance the strength and toughness of matrix materials, especially demonstrating significant application value in aerospace and high-temperature engineering. However, carbon fiber undergoes slow oxidation above 400℃, generating microscopic defects on its surface that lead to stress concentration and a severe decline in mechanical properties. The susceptibility of carbon fiber to oxidation or mechanical damage under high-temperature engineering environments severely limits its application.

[0003] To overcome these drawbacks of carbon fibers, a common approach is to use carbon fibers to prepare composite materials with other materials, such as carbon fiber-reinforced ceramic matrix composites. However, because the matrix material of the composite material often differs greatly from the physical characteristics of carbon fibers, such as modulus and coefficient of thermal expansion, stress concentration easily occurs at the interface, thereby inducing brittle fracture of the carbon fibers.

[0004] In order to solve the above problems, people have been seeking an ideal technological solution. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for preparing MAB phase-coated carbon fibers.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing MAB phase coating coated carbon fiber involves sequentially treating carbon fiber with concentrated nitric acid, sensitizing solution, and activating solution. The treated carbon fiber is then immersed in a chemical plating solution for plating. After plating, the carbon fiber is sequentially cleaned and dried, and then heat-treated at 700-1200℃ for at least 0.5 hours in an inert atmosphere to obtain MAB phase coating coated carbon fiber. The chemical plating solution consists of: cobalt sulfate 21 g / L, sodium tungstate 5-23 g / L, dimethylaminoborane 2-4 g / L, sodium citrate 20-30 g / L, and deionized water as the solvent.

[0008] The sensitization solution contained SnCl2·H2O at a concentration of 20-40 g / L, HCl at a concentration of 2.5 ml / L, and deionized water as the solvent.

[0009] The activation solution contained PdCl2 at a concentration of 0.25 g / L, HCl at a concentration of 2.5 ml / L, and deionized water as the solvent.

[0010] Carbon fibers are soaked in concentrated nitric acid for 6-10 hours at a temperature of 50-80°C. After soaking, the carbon fibers are ultrasonicated in deionized water for 5-15 minutes, then dried, and then sensitized.

[0011] After being treated with concentrated nitric acid, the carbon fiber is immersed in the sensitizing solution for 5-10 minutes, and then rinsed with deionized water 3-5 times.

[0012] After the carbon fiber is treated with the sensitizing solution, it is immersed in the activation solution for 5-10 minutes, and then rinsed with deionized water 3-5 times.

[0013] During the plating process, the stirring speed is 100-300 r / min, the temperature is 60-90℃, and the duration is 90-150 min.

[0014] After removing the carbon fiber from the chemical plating solution, it is washed with deionized water 3-5 times and dried at 50-70℃ for 6-12 hours.

[0015] A type of MAB phase coating coated carbon fiber is prepared by the above-described preparation method.

[0016] A MAB phase coating for carbon fiber includes carbon fiber and a W-Co-B ternary boride MAB phase coating on the surface of the carbon fiber.

[0017] This invention represents a significant advancement and substantial improvement over existing technologies. Specifically, it provides a MAB phase coating for carbon fibers. The carbon fiber surface is coated with a W-Co-B ternary boride MAB phase coating. The W-Co-B material has a shear modulus of approximately 200 GPa and a bulk modulus of approximately 340 GPa, with a relatively low theoretical Pugh modulus ratio index, indicating good flexibility and ductility. This demonstrates excellent shear deformation capability, which is beneficial for redistributing stress at the fiber-matrix interface, effectively alleviating stress concentration at the interface. Furthermore, the W-Co-B material in this invention possesses an MAB phase, whose unique layered structure enables crack deflection at the interface, effectively extending the crack propagation path, enhancing energy dissipation, and thus improving the fracture toughness of the composite material. In addition, W-Co-B can form tungsten cobalt oxide and B2O3 phases under oxidizing conditions, resulting in a certain volume expansion that effectively blocks voids and cracks on the carbon fiber surface. Therefore, preparing a W-Co-B interface on the carbon fiber surface can effectively suppress high-temperature oxidation damage to the carbon fiber.

[0018] This invention employs a chemical plating method to prepare a MAB-phase tungsten cobalt boron coating on the surface of carbon fibers. The formation of the MAB phase effectively alleviates interfacial stress. The chemical plating process results in a uniform coating thickness and dense structure on the carbon fiber surface, and is simpler, less costly, and has a shorter cycle time. The MAB-phase W-Co-B ternary boride coating prepared by this invention coats carbon fibers. Based on the synergistic effect of the intrinsic properties of the coating material and the deposition process, a highly promising composite material is formed, effectively solving the problem of easy oxidation damage to carbon fibers in composite materials under high-temperature oxidizing environments. Attached Figure Description

[0019] Figure 1 This is a SEM image of the W-Co-B coating obtained in Example 1 of the present invention.

[0020] Figure 2 The image shows the XRD pattern of the W-Co-B coating obtained in Example 1 of this invention under Ar heat treatment at 700℃.

[0021] Figure 3 This is a SEM image of the original carbon fiber used in this invention under high-temperature oxidation at 600℃.

[0022] Figure 4 This is a SEM image of the W-Co-B coating obtained in Example 1 of the present invention under high-temperature oxidation at 600℃. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below through specific embodiments. In the following embodiments, the concentrated nitric acid used is commercially available concentrated nitric acid with a mass fraction of 68%, and the carbon fiber is continuous fiber with a diameter of 7-8 μm.

[0024] Example 1

[0025] This embodiment provides a method for preparing MAB phase coating coated carbon fibers, including the following steps:

[0026] Step 1: Place the carbon fiber in a concentrated nitric acid solution and keep it in a water bath at 60°C for 8 hours. Remove the carbon fiber, rinse it repeatedly with clean water, and then place it in deionized water and sonicate for 10 minutes. Finally, air dry it.

[0027] Step 2: Immerse the carbon fibers treated in Step 1 in the sensitization solution for 5 minutes for sensitization. After removal, rinse 4 times with deionized water. The composition of the sensitization solution is: SnCl2·H2O concentration of 20g / L, HCl concentration of 2.5ml / L, and deionized water as solvent.

[0028] Step 3: Immerse the sensitized carbon fibers in the activation solution for 5 minutes to activate them. After activating, rinse them three times with deionized water. The activation solution consists of PdCl2 concentration of 0.25 g / L, HCl concentration of 2.5 ml / L, and deionized water as the solvent.

[0029] Step 4: The chemical plating solution consists of 21 g / L cobalt sulfate, 5 g / L sodium tungstate, 4 g / L dimethylaminoborane, and 30 g / L sodium citrate, with deionized water as the solvent.

[0030] Step 5: Place the carbon fiber treated in Step 3 into a chemical plating solution, adjust the temperature to 70℃, stir at 300r / min for 120min for chemical plating, take out the reacted carbon fiber, wash it 5 times with deionized water, put it in an oven at 60℃ for 8h, and then put the carbon fiber into a tube furnace, introduce Ar gas and heat it to 700℃ for 1h to obtain MAB phase coating coated carbon fiber.

[0031] The SEM image of the MAB phase coating on the carbon fiber obtained in this embodiment is shown below. Figure 1 ,Depend on Figure 1 It can be seen that the W-Co-B coating obtained on the carbon fiber surface has a spherical structure, uniform coating thickness, and dense structure.

[0032] The XRD pattern of the MAB phase coating on the carbon fiber obtained in this embodiment is shown in [reference]. Figure 2 .

[0033] The SEM image of the carbon fiber raw material used in this embodiment after oxidation at 600℃ for 5 minutes is shown below. Figure 3 ,Depend on Figure 3 It can be seen that pores and cracks are generated on the sample surface, indicating that the carbon fiber surface has been oxidized and damaged.

[0034] The SEM image of the MAB phase coating-coated carbon fiber obtained in this embodiment after high-temperature oxidation at 600℃ for 5 min is shown below. Figure 4 ,Depend on Figure 4 It can be seen that the W-Co-B ternary boride MAB phase coating produced a certain volume expansion, and there was no oxidation damage on the carbon fiber surface, indicating that the W-Co-B coating effectively suppressed the oxidation damage of the carbon fiber.

[0035] Example 2

[0036] This embodiment provides a method for preparing MAB phase coating coated carbon fibers, including the following steps:

[0037] Step 1: Place the carbon fiber in a concentrated nitric acid solution and keep it in a water bath at 60°C for 8 hours. Remove the carbon fiber, rinse it repeatedly with clean water, and then place it in deionized water and sonicate for 10 minutes. Finally, air dry it.

[0038] Step 2: Immerse the carbon fibers treated in Step 1 in the sensitization solution for 5 minutes for sensitization. After removal, rinse with deionized water 3-5 times. The composition of the sensitization solution is: SnCl2·H2O concentration of 20g / L, HCl concentration of 2.5ml / L, and deionized water as solvent.

[0039] Step 3: Immerse the sensitized carbon fibers in the activation solution for 5 minutes to activate them. After rinsing, rinse them 5 times with deionized water. The activation solution consists of PdCl2 concentration of 0.25 g / L, HCl concentration of 2.5 ml / L, and deionized water as the solvent.

[0040] Step 4: The chemical plating solution consists of 21 g / L cobalt sulfate, 23 g / L sodium tungstate, 4 g / L dimethylaminoborane, and 20 g / L sodium citrate, with deionized water as the solvent.

[0041] Step 5: Place the carbon fiber treated in Step 3 into a chemical plating solution, adjust the temperature to 70℃, stir at 300r / min for 120min, take out the reacted carbon fiber, wash it with deionized water 3-5 times, put it in an oven and dry it at 70℃ for 8h, put the carbon fiber into a tube furnace, introduce Ar gas and heat it to 700℃ and hold it for 30min to obtain MAB phase coating coated carbon fiber.

[0042] Example 3

[0043] This embodiment provides a method for preparing MAB phase coating coated carbon fibers, including the following steps:

[0044] Step 1: Place the carbon fiber in a concentrated nitric acid solution and keep it in a water bath at 60°C for 8 hours. Remove the carbon fiber, rinse it repeatedly with clean water, and then place it in deionized water and sonicate for 10 minutes. Finally, air dry it.

[0045] Step 2: Immerse the carbon fibers treated in Step 1 in the sensitization solution for 5 minutes for sensitization. After removal, rinse 3 times with deionized water. The composition of the sensitization solution is: SnCl2·H2O concentration of 20g / L, HCl concentration of 2.5ml / L, and deionized water as solvent.

[0046] Step 3: Immerse the sensitized carbon fibers in the activation solution for 5 minutes to activate them. After activating, rinse them 4 times with deionized water. The activation solution consists of PdCl2 concentration of 0.25 g / L, HCl concentration of 2.5 ml / L, and deionized water as the solvent.

[0047] Step 4: The chemical plating solution consists of 21 g / L cobalt sulfate, 5 g / L sodium tungstate, 2 g / L dimethylaminoborane, and 20 g / L sodium citrate, with deionized water as the solvent.

[0048] Step 5: Chemical plating: Place the carbon fiber treated in Step 3 into the chemical plating solution, adjust the temperature to 70℃, stir at medium speed for 120 minutes, take out the reacted carbon fiber, wash it 5 times with deionized water, put it in a room temperature oven at 60℃ and dry it for 8 hours, put the carbon fiber into a tube furnace, introduce Ar gas and heat it to 700℃ and keep it at that temperature for 1 hour to obtain MAB phase coating on the carbon fiber.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for preparing MAB phase coated carbon fibers, characterized by: The carbon fiber is treated with concentrated nitric acid, sensitizing solution and activating solution in sequence, then immersed in a chemical plating solution for plating, and then cleaned and dried, and then heated to 700-1200℃ in an inert atmosphere for at least 0.5 h to obtain the carbon fiber coated with MAB phase coating; the chemical plating solution comprises 21 g / L of cobalt sulfate, 5-23 g / L of sodium tungstate, 2-4 g / L of dimethylaminoborane and 20-30 g / L of sodium citrate, and deionized water is used as the solvent.

2. The method of claim 1, wherein: In the sensitizing solution, the concentration of SnCl2·H2O is 20-40 g / L, the concentration of HCl is 2.5 ml / L, and deionized water is used as the solvent.

3. The method of claim 2, wherein: In the activating solution, the concentration of PdCl2 is 0.25 g / L, the concentration of HCl is 2.5 ml / L, and deionized water is used as the solvent.

4. The method of claim 3, wherein: The carbon fiber is immersed in concentrated nitric acid for 6-10 h at 50-80℃, and then ultrasonically cleaned in deionized water for 5-15 min, and then dried, and then sensitized.

5. The method of claim 4, wherein: The carbon fiber treated with concentrated nitric acid is immersed in the sensitizing solution for 5-10 min, and then cleaned with deionized water for 3-5 times.

6. The method of claim 5, wherein: The carbon fiber treated with the sensitizing solution is immersed in the activating solution for 5-10 min, and then cleaned with deionized water for 3-5 times.

7. The method of claim 6, wherein: During the plating, the stirring speed is 100-300 r / min, the temperature is 60-90℃, and the time is 90-150 min.

8. The method of claim 7, wherein: After the carbon fiber is taken out of the chemical plating solution, it is cleaned with deionized water for 3-5 times, and then dried at 50-70℃ for 6-12 h.

9. A MAB phase coating coated carbon fiber, characterized by: Prepared by the method of any one of claims 1-8.

10. A MAB phase coating coated carbon fiber, characterized by: The carbon fiber coated with W-Co-B ternary boride MAB phase coating.

Images