Reinforced boron nitride fiber and preparation method thereof
By dry distillation of the boron nitride fibers and precursors under a nitrogen atmosphere, and injecting ammonia into the nitrogen to deposit a repair layer, combined with high-temperature ceramicization treatment, the problems of surface defects and insufficient strength of the boron nitride fibers are solved, and the tensile strength and chemical bonding strength of the fiber are significantly improved.
Patent Information
- Application Number
- CN202311747022.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-19
- Publication Date
- 2025-06-20
AI Technical Summary
The surface of boron nitride fibers prepared by the existing vapor deposition method has defects, which are prone to cracks and have poor strength, which limits its use in later-stage weaving and other applications.
The boron nitride fibers and precursors are subjected to dry distillation under a nitrogen atmosphere, and then ammonia is introduced to deposit them on the fiber surface. Finally, a repair layer is formed by high-temperature ceramicization treatment to enhance the strength of the fibers.
Through this method, the surface of the generated boron nitride fibers forms a repair layer, which significantly improves its tensile strength, and the chemical bond strength of the repair layer and the fiber is improved, enhancing the overall performance of the fiber.
Smart Images
Figure CN120174632A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of boron nitride fiber preparation, and specifically relates to a reinforced boron nitride fiber and a preparation method thereof. Background Art
[0002] When enhancing the surface strength of fibers, the chemical vapor deposition method is commonly used. The existing chemical vapor deposition method continuously introduces reaction gases or substances into the reaction chamber, and the reaction proceeds smoothly through heating and other means. However, the boron nitride fibers prepared by this method have defects on the surface, are prone to cracks, and have poor strength, resulting in great limitations in later applications such as weaving. Summary of the Invention
[0003] The present invention designs a preparation method of a reinforced boron nitride fiber, including the following steps:
[0004] Placing the boron nitride fiber and the precursor in the reaction chamber,
[0005] Under a nitrogen atmosphere, performing carbonization treatment on the precursor in the reaction chamber,
[0006] Introducing ammonia gas into the reaction chamber to deposit on the surface of the boron nitride fiber,
[0007] Taking out the deposited boron nitride fiber after cooling treatment,
[0008] Performing ceramization treatment on the deposited boron nitride fiber to obtain a reinforced boron nitride fiber.
[0009] Preferably, the precursor is a polyborazylene precursor,
[0010] Performing carbonization treatment on the polyborazylene precursor;
[0011] The carbonization treatment includes: raising the temperature from room temperature to 570 - 630 °C, and the heating duration is 1.5 - 2.5 h.
[0012] Preferably, the precursor is a borazine precursor,
[0013] Before performing the carbonization treatment, pre-treating the borazine precursor to cause self-polymerization of the borazine to obtain a polyborazylene precursor,
[0014] Performing carbonization treatment on the polyborazylene precursor.
[0015] The pre-treatment includes: raising the temperature from room temperature to 180 - 220 °C,
[0016] The carbonization treatment includes: raising the temperature from room temperature to 570 - 630 °C, and the heating duration is 1.5 - 2.5 h.
[0017] Preferably, a vessel is placed at the middle position of the reaction chamber.
[0018] The precursor is placed in the vessel, and boron nitride fibers are spread above the vessel.
[0019] Preferably, the gas flow rate of ammonia introduced is 0.3 - 0.7 m 3 / h, and it is kept warm for 2.5 - 3.5 h at the temperature of the dry distillation treatment. The polyboron nitride after dry distillation reacts with ammonia, and the product deposits on the surface of the boron nitride fibers to form a repair layer.
[0020] Preferably, the cooling treatment includes: cooling from the temperature of the dry distillation treatment to room temperature. During the cooling treatment, nitrogen is introduced into the reaction chamber to remove the unreacted ammonia in the reaction chamber.
[0021] Preferably, the treatment temperature of the ceramization treatment is 1150 - 1250 °C. During the ceramization treatment, nitrogen is introduced into the reaction chamber at a flow rate of 0.2 - 1.0 m 3 / h. The ceramization treatment can promote the growth of crystal grains on the fiber surface to obtain the final product.
[0022] The present invention also designs a reinforced boron nitride fiber, which is prepared by using the above preparation method.
[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: By heating the boron nitride precursor in the reaction chamber for dry distillation, the gaseous precursor components fill the entire chamber. Boron nitride fibers with surface defects are placed above the precursor, ammonia is introduced and heated for reaction, and the product deposits on the fiber surface. Finally, the deposits on the fiber surface are ceramized by high-temperature treatment to obtain boron nitride fibers covered with a repair layer.
[0024] Boron nitride precursor is selected, and no other substances are introduced in the preparation method. The generated boron nitride has the same molecular structure unit as the boron nitride fiber, which improves the chemical bonding strength between the repair layer and the boron nitride fiber. The preparation method of the present invention is simple, the thickness of the repair layer is controllable, and the tensile strength of the boron nitride fiber is significantly improved. Description of the Drawings
[0025] Figure 1 It is the electron microscope image of the reinforced boron nitride fiber in the embodiment of the present invention.
[0026] Figure 2 It is the comparison chart of the tensile strength of the boron nitride fiber before and after reinforcement in the embodiment of the present invention.
[0027] Figure 3 It is the infrared image of the boron nitride fiber before and after reinforcement in the embodiment of the present invention. Detailed Embodiments
[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention.
[0029] Example 1
[0030] This embodiment provides a method for preparing enhanced boron nitride fibers, including the following steps:
[0031] Step 1: Place a vessel at the middle position of the reaction chamber, place the polyborazylene precursor in the vessel, and spread the boron nitride fibers above the vessel.
[0032] Step 2: Under a nitrogen atmosphere, raise the temperature from room temperature to 570 °C, with a heating duration of 1.5 h, and perform carbonization treatment on the polyborazylene precursor in the reaction chamber.
[0033] Step 3: At a gas flow rate of 0.3 m 3 / h, introduce ammonia gas into the reaction chamber, and keep it at 570 °C for 2.5 h. The carbonized polyborazylene reacts with ammonia gas, and the product deposits on the surface of the boron nitride fibers to form a repair layer.
[0034] Step 4: Introduce nitrogen gas to remove the unreacted ammonia gas in the reaction chamber. After cooling from 570 °C to room temperature, take out the deposited boron nitride fibers.
[0035] Step 5: Perform ceramization treatment on the deposited boron nitride fibers at a temperature of 1150 °C. During the ceramization treatment, introduce nitrogen gas into the reaction chamber at a flow rate of 0.2 m 3 / h to promote the growth of crystal grains on the fiber surface and obtain enhanced boron nitride fibers.
[0036] Example 2
[0037] This embodiment provides a method for preparing enhanced boron nitride fibers, including the following steps:
[0038] Step 1: Place a vessel at the middle position of the reaction chamber, place the cycloborazane precursor in the vessel, and spread the boron nitride fibers above the vessel.
[0039] Step 2: Raise the temperature in the reaction chamber from room temperature to 200 °C to pre-treat the cycloborazane precursor, causing the cycloborazane to self-polymerize to obtain a polyborazylene precursor.
[0040] Step 3: Under a nitrogen atmosphere, raise the temperature from room temperature to 600 °C, with a heating duration of 2 h, and perform carbonization treatment on the polyborazylene precursor in Step 2.
[0041] Step 4: At a gas flow rate of 0.5 m 3With a gas flow rate of [X] / h, ammonia gas is introduced into the reaction chamber and kept at 600 °C for 3 h. The pyrolyzed polyboron nitride reacts with ammonia gas, and the product deposits on the surface of the boron nitride fiber to form a repair layer.
[0042] Step 5: Nitrogen gas is introduced to remove the unreacted ammonia gas in the reaction chamber. After cooling from 600 °C to room temperature, the deposited boron nitride fiber is taken out.
[0043] Step 6: The deposited boron nitride fiber is subjected to ceramization treatment at a temperature of 1200 °C. During the ceramization treatment, nitrogen gas is introduced into the reaction chamber at a flow rate of 0.6 m 3 / h to promote the growth of grains on the fiber surface, and the enhanced boron nitride fiber as shown in Figure 1 is obtained.
[0044] As shown in Figure 2 , the tensile strength of the enhanced boron nitride fiber prepared in this example is significantly improved compared with that before enhancement. As shown in Figure 3 , Figure 3 is the infrared spectrum of the fiber before and after vapor deposition, indicating that the structure of the deposit is the same as that of the boron nitride fiber and the two have good bonding.
[0045] Example 3
[0046] This example provides a method for preparing an enhanced boron nitride fiber, including the following steps:
[0047] Step 1: Place a vessel in the middle of the reaction chamber, put the polyboron nitride precursor in the vessel, and spread the boron nitride fiber above the vessel.
[0048] Step 2: Under a nitrogen atmosphere, heat from room temperature to 630 °C with a heating duration of 2.5 h to pyrolyze the polyboron nitride precursor in the reaction chamber.
[0049] Step 3: With a gas flow rate of 0.7 m 3 / h, introduce ammonia gas into the reaction chamber and keep it at 630 °C for 3.5 h. The pyrolyzed polyboron nitride reacts with ammonia gas, and the product deposits on the surface of the boron nitride fiber to form a repair layer.
[0050] Step 4: Introduce nitrogen gas to remove the unreacted ammonia gas in the reaction chamber. After cooling from 630 °C to room temperature, take out the deposited boron nitride fiber.
[0051] Step 5: The deposited boron nitride fiber is subjected to ceramization treatment at a temperature of 1250 °C. During the ceramization treatment, nitrogen gas is introduced into the reaction chamber at a flow rate of 1 m 3 / h to promote the growth of grains on the fiber surface, and the enhanced boron nitride fiber is obtained.
[0052] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing enhanced boron nitride fibers, characterized in that, It includes the following steps: Place boron nitride fibers and a precursor in a reaction chamber. Under a nitrogen atmosphere, perform carbonization treatment on the precursor in the reaction chamber. Introduce ammonia gas into the reaction chamber to deposit on the surface of the boron nitride fibers. After cooling treatment, take out the deposited boron nitride fibers. Perform ceramization treatment on the deposited boron nitride fibers to obtain reinforced boron nitride fibers.
2. The method for preparing enhanced boron nitride fibers according to claim 1, characterized in that, The precursor is a polyborazylene precursor. Perform carbonization treatment on the polyborazylene precursor. The carbonization treatment includes: heating from room temperature to 570 - 630 °C, and the heating duration is 1.5 - 2.5 h.
3. The method for preparing enhanced boron nitride fibers according to claim 1, characterized in that, The precursor is a borazine precursor. Before performing carbonization treatment, perform pretreatment on the borazine precursor to obtain a polyborazylene precursor. Perform carbonization treatment on the polyborazylene precursor.
4. The method for preparing enhanced boron nitride fibers according to claim 3, characterized in that, The pretreatment includes: heating from room temperature to 180 - 220 °C. The carbonization treatment includes: heating from room temperature to 570 - 630 °C, and the heating duration is 1.5 - 2.5 h.
5. The method for preparing enhanced boron nitride fibers according to claim 1, characterized in that, Place a vessel at the middle position of the reaction chamber. Place the precursor in the vessel, and spread the boron nitride fibers above the vessel.
6. The method for preparing enhanced boron nitride fibers according to claim 1, characterized in that, The gas flow rate of ammonia introduced is 0.3 - 0.7 m 3 / h, and it is kept warm for 2.5 - 3.5 h at the temperature of dry distillation treatment.
7. The method for preparing enhanced boron nitride fibers according to claim 1, characterized in that, The cooling treatment includes: cooling from the temperature of the carbonization treatment to room temperature.
8. The method for preparing enhanced boron nitride fibers according to claim 1, characterized in that, During the cooling treatment, introduce nitrogen gas into the reaction chamber.
9. The method for preparing enhanced boron nitride fibers according to claim 1, characterized in that, The treatment temperature of the ceramization treatment is 1150 - 1250 °C. During the ceramization process, nitrogen is introduced into the reaction chamber at a flow rate of 0.2 - 1.0 m 3 / h.
10. An enhanced boron nitride fiber, characterized in that, Prepared by using the preparation method according to any one of claims 1 - 9.