ZrC nanowire prepared by in-situ reaction in composite material as well as method and application of ZrC nanowire

Abstract

The invention discloses a ZrC nanowire prepared by in-situ reaction in a composite material and a method and application thereof, and belongs to the technical field of nano materials. According to the method disclosed by the invention, nano zirconium sol and metal Ni particles are uniformly introduced into a low-density carbon-based or ceramic composite material through vacuum impregnation, and then in-situ reaction is carried out in the material in combination with a chemical vapor deposition method to prepare the ZrC nanowire which is excellent in morphology and size and high in yield; the ZrC nanowire prepared by the method has the advantages of good crystallinity, no other impurity phase, neat morphology, regular slender rod shape and large length-diameter ratio, and has important significance in the fields of high-temperature thermal protection, bearing and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterials, and particularly relates to ZrC nanowires prepared by in-situ reaction in a composite material, a method and an application thereof. Background Art

[0002] Ultra-high temperature ceramic materials refer to a special type of materials that can maintain chemical stability in extremely high temperature environments above 2000 °C, mainly including carbides, nitrides and borides of transition metals, etc. Common carbide ultra-high temperature ceramics include ZrC, HfC and TaC, etc. Among them, ZrC ceramics have attracted great attention in the ultra-high temperature field due to their low cost, high melting point (3693K), high hardness (25.5 GPa), excellent thermal conductivity and excellent wear resistance. Nanomaterials such as nanoparticles, whiskers, nanowires and nanotubes, etc., have received extensive attention due to their good physical and chemical properties and unique geometric characteristics.

[0003] One-dimensional nanomaterials, with their unique structural characteristics, that is, the radial size is strictly limited to 100 nanometers (nm) and below, while the extension in the length direction far exceeds its radial size, forming a remarkable high specific surface area characteristic. This structural characteristic not only enables one-dimensional nanomaterials to exhibit unique advantages in terms of interfacial interaction and surface effect, but also endows them with excellent optical, thermal and mechanical properties. ZrC nanowires, as an important member of one-dimensional nanomaterials, have particularly prominent properties. It skillfully combines the high-temperature stability of bulk ceramic materials with the significant advantages of one-dimensional nanomaterials in mechanical properties. Specifically, ZrC nanowires not only inherit the excellent high-temperature resistance of bulk ZrC ceramic materials and can maintain structural stability in extremely high temperature environments, but also exhibit the unique high strength, high toughness and good fatigue resistance of one-dimensional nanomaterials. Given the unique advantages of ZrC nanowires in terms of performance, using them as the second-phase reinforcement phase to prepare various ZrC nanowire toughened composite materials has become a hot topic in the current field of materials science research. Such composite materials combine the high performance of ZrC nanowires with the advantages of matrix materials and are expected to show broad application prospects in the fields of high-temperature structural materials, wear-resistant materials, thermal protection materials, etc. At the same time, in-depth research on ZrC nanowire toughened composite materials will also provide strong support for the development of new high-performance materials.

[0004] However, there are currently few reports on the in-situ preparation of nanomaterials in C / C composites. The literature "In-situ homogeneous growth of ZrC nanowires on carbon cloth and their effects on flexural properties of carbon / carbon composites, Ningning Yan, Xiaohong Shi, Kun Li, et.al. Composites Part B, 2018, 154:200-208." discloses a method for synthesizing zirconium carbide nanowires by precursor pyrolysis. This method uses zirconium carbide precursor as the zirconium carbide source and nickel nitrate hexahydrate as the catalyst, and synthesizes zirconium carbide nanowires on carbon cloth at 1500-1600 °C. The prepared nanowires have a high purity, but a relatively thick diameter, about 1 μm, and the preparation temperature required by this method is relatively high. The generation of zirconium carbide nanowires highly depends on the concentration ratio of the precursor. The Chinese patent application with the publication number CN113088923A discloses a method for preparing ZrC nanowires in C / C composites by precursor pyrolysis. This method uses zirconium carbide precursor as the zirconium carbide source and nickel nitrate hexahydrate as the catalyst, and synthesizes zirconium carbide nanowires on carbon cloth at 1500-1600 °C. The traditional CVD method for preparing ZrC nanowires requires a high temperature, low yield, and the morphology and structure of the nanowires are unstable and are easily affected by process parameters. Summary of the Invention

[0005] The object of the present invention is to provide a method and application for preparing ZrC nanowires by in-situ reaction in a composite material to solve the technical problem of the complex preparation process of existing ZrC nanowires.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention discloses a method for preparing ZrC nanowires by in-situ reaction in a composite material, including the following steps:

[0008] Soak a low-density carbon-based or ceramic composite material in a zirconium metal salt sol for vacuum impregnation to obtain an impregnated composite material;

[0009] Perform an in-situ reaction in the impregnated composite material by chemical vapor deposition to prepare ZrC nanowires.

[0010] Further, the density of the low-density carbon-based or ceramic composite material is 0.4-1.5 g / cm 3 ;

[0011] The porosity of the low-density carbon-based or ceramic composite material is 30%-95%.

[0012] Further, the metal salt zirconium sol is obtained by mixing a metal salt solution and a nano zirconium sol; the metal salt solution is a Ni(NO3)2 solution, a NiCl2 solution, a NiSO4 solution, an FeCl3 solution, or an Fe2(SO4)3 solution;

[0013] The mass ratio of the nano metal sol to the metal salt solution is 2:1 to 20:1.

[0014] Further, the concentration of the metal salt solution is 0.1-3 mol / L.

[0015] Further, the pressure of the vacuum impregnation is 50-100 Pa, and the pressure holding time is 10-20 min.

[0016] Further, before in-situ reaction preparation of ZrC nanowires by chemical vapor deposition, the impregnated composite material is dried; the drying temperature is 40-60 °C, and the time is 5-10 h.

[0017] Further, the specific steps for in-situ reaction preparation of ZrC nanowires by chemical vapor deposition in the impregnated composite material are as follows:

[0018] Suspend the impregnated composite material at the deposition area position of the chemical vapor infiltration furnace, load the ZrCl4 powder in the deposition furnace mold, turn on the vacuum pump to evacuate, then set the heating program, after reaching the preset temperature, introduce hydrocarbon gas, Ar, and H2 for deposition, after the deposition is completed, turn off the hydrocarbon gas and H2, adjust the Ar flow rate, turn off the heating power supply and let it cool naturally, and take out the sample after cooling to room temperature to obtain ZrC nanowires prepared by in-situ reaction in the composite material.

[0019] Further, the molar ratio of the ZrCl4 powder to the hydrocarbon gas is 5:1 to 10:1;

[0020] The process parameters of the evacuation are: pump the furnace pressure to 500-1000 Pa, hold the pressure for 3-5 h, after the pressure holding is completed, turn on the vacuum pump, and then set the heating program;

[0021] The process parameters of the heating program are: heat up to 1100-1200 °C in 2-3 h, and introduce Ar at 300-500 mL / min during the heating period;

[0022] The hydrocarbon gas is CH4, C3H6, or natural gas;

[0023] The flow rates of the hydrocarbon gas, Ar, and H2 are 100 - 300 mL / min, 200 - 600 mL / min, and 300 - 500 mL / min respectively; the deposition time is 2 - 5 h;

[0024] The flow rate of Ar is adjusted to 200 - 400 ml / min.

[0025] The present invention also discloses ZrC nanowires prepared by the above preparation method.

[0026] The present invention also discloses the application of ZrC nanowires prepared by in-situ reaction in the above composite material in ultra-high temperature ceramic modified C / C composite materials.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention discloses a method for in-situ reaction to prepare ZrC nanowires in a composite material. By vacuum impregnation, nano-zirconium sol and metal Ni particles are uniformly introduced into a low-density carbon-based or ceramic composite material, and then combined with chemical vapor deposition, ZrC nanowires with excellent morphology, size, and large yield are prepared by in-situ reaction in the material; the preparation temperature required by this method is low, and it can be deposited on more types of materials; in this method, the reactants enter in a gaseous state, so that in-situ preparation of ZrC nanowires in a low-density carbon-based or ceramic composite material can be realized, with simple operation and excellent products; at the same time, the gas-phase reaction deposition has good wrap-around plating performance, and ZrC nanowires can be prepared on complex structures, with a wide application range and good economic and social benefits.

[0029] The present invention also discloses ZrC nanowires in-situ prepared by the above method. According to relevant experimental results, by using the preparation method disclosed in the present invention, the ZrC nanowires have good crystallinity, no other impurity phases, neat morphology, are regular fine rod-shaped, and have a large aspect ratio, which is of great significance in the fields of high-temperature thermal protection, load-bearing, etc. Description of the Drawings

[0030] Figure 1 It is the XRD pattern of the ZrC nanowires prepared in Example 1 of the present invention;

[0031] Figure 2 It is the SEM image of the ZrC nanowires prepared in Example 1 of the present invention;

[0032] Among them: a - low-magnification SEM image; b - high-magnification SEM image;

[0033] Figure 3 It is the SEM image of the ZrC nanowires prepared in Example 2 of the present invention;

[0034] Figure 4SEM image of the ZrC nanowires prepared in Example 3 of the present invention;

[0035] Figure 5 SEM image of the ZrC nanowires prepared in Example 4 of the present invention. Detailed implementation manners

[0036] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meaning understood by those skilled in the art regarding the present invention. In case of conflict, the definition in this specification shall prevail.

[0037] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not in any way limit the scope of the present invention, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0038] In this article, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of a numerical range or percentage range should be regarded as having covered and specifically disclosed all possible sub-ranges and individual values within the range (including integers and fractions).

[0039] In this article, unless otherwise specified, "comprising", "including", "containing", "having" or similar terms cover the meanings of "consisting of" and "consisting essentially of". For example, "A comprises a" covers the meanings of "A comprises a and others" and "A consists only of a".

[0040] In this article, for the sake of brevity of description, all possible combinations of all technical features in each embodiment or example are not described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope described in this specification.

[0041] The present invention provides a method for in-situ reaction preparation of ZrC nanowires in a composite material, comprising the following steps:

[0042] Immerse a low-density carbon-based or ceramic composite material in a beaker containing Ni(NO3)2 nanometer zirconium sol, and then place the beaker in a vacuum impregnation chamber. Turn on the vacuum pump, set the pressure to 50 - 100 Pa, and keep the pressure for 10 - 20 min to obtain an impregnated composite material;

[0043] The impregnated composite material is dried in an oven at 40 - 60 °C for 5 - 10 h, and then suspended at the deposition area position of the chemical vapor infiltration furnace. 50 - 100 g of ZrCl4 powder is placed in the deposition furnace mold. The vacuum pump is turned on, and the furnace pressure is pumped down to 500 - 1000 Pa and held for 3 - 5 h. After the pressure holding is completed, the vacuum pump is turned on again, and the heating program is set. The temperature is raised to 1100 - 1200 °C in 2 - 3 h, and Ar is introduced at 300 - 500 mL / min during the heating period.

[0044] After reaching the temperature, CH4 is introduced at 100 - 300 mL / min, Ar at 200 - 600 mL / min, and H2 at 300 - 500 mL / min, and heat preservation and deposition are carried out for 2 - 5 h. After the deposition is completed, CH4 and H2 are turned off, the Ar flow rate is adjusted to 200 - 400 ml / min, the heating power supply is turned off and the temperature is allowed to drop naturally. After the temperature drops to room temperature, the sample is taken out to obtain ZrC nanowires in-situ prepared in the low-density carbon-based or ceramic composite material.

[0045] Preferably, the Ni(NO3)2 nanozirconia sol is prepared by mixing nanozirconia sol and Ni(NO3)2 solution, and their mass ratio is 2:1 - 20:1; the concentration of the Ni(NO3)2 solution is 0.1 - 3 mol / L.

[0046] Preferably, Ni(NO3)2 can be replaced by Ni / Fe chlorides or sulfates.

[0047] Preferably, the nanozirconia sol can be replaced by nanosilica sol, nanohafnia sol, or nanotantalum sol, and the corresponding ZrCl4 powder can be replaced by SiCl4, HfCl4, or TaCl5.

[0048] Preferably, the CH4 can be replaced by C3H6 or natural gas.

[0049] The following is a further elaboration of the present invention in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not 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 also fall within the scope defined by the appended claims of this application.

[0050] Conventional instruments and equipment in the art are used in the following embodiments. For the experimental methods without specific conditions noted in the following embodiments, they are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. Various raw materials are used in the following embodiments. Unless otherwise stated, commercially available products are used, and their specifications are the conventional specifications in the art. In the description of the present invention and the following embodiments, unless otherwise specified, "%" represents weight percentage, "parts" represents weight parts, and the ratio represents weight ratio.

[0051] Example 1

[0052] A method for in-situ reaction preparation of ZrC nanowires in a composite material, comprising the following steps:

[0053] Step 1: Low-density C / C composite materials with a density of 0.45 g / cm 3 and dimensions of 10 mm × 10 mm × 10 mm are successively polished with 400, 800, and 1000 grit sandpapers, ultrasonically cleaned with absolute ethanol for 0.5 h, and then placed in an oven at 70 °C for drying and standby;

[0054] Step 2: Weigh an appropriate amount of Ni(NO3)2 powder and put it into a beaker, pour in an appropriate amount of absolute ethanol, stir with a glass rod to prepare an ethanol solution of Ni(NO3)2 with a concentration of 0.05 mol / L. Mix the nanometer zirconium sol and the Ni(NO3)2 solution according to a mass ratio of 20:1 to obtain a Ni(NO3)2 nanometer zirconium sol;

[0055] Step 3: Put the low-density C / C composite material in Step 1 into a beaker containing the nanometer zirconium Ni(NO3)2 solution, then put it into a vacuum impregnation box, turn on the vacuum pump, set the pressure to 100 Pa, keep the pressure for 10 min, take out the low-density C / C, and place it in an oven at 40 °C for drying;

[0056] Step 4: Hang the dried impregnated composite material at the deposition area position of the chemical vapor infiltration furnace, and put 50 g of ZrCl4 powder in the mold in the low-temperature area of the deposition furnace; turn on the vacuum pump, pump the furnace pressure down to 500 Pa, and keep the pressure for 3 h;

[0057] Step 5: After the pressure holding is completed, turn on the vacuum pump, set the heating program, heat up to 1200 °C in 2.5 h, and pass Ar at a flow rate of 300 ml / min during the heating;

[0058] Step 6: After reaching the temperature, pass CH4 at 100 mL / min, Ar at 200 mL / min, and H2 at 300 mL / min, and keep the temperature for deposition for 2 h;

[0059] Step 7: After the deposition is completed, turn off CH4 and H2, adjust the Ar flow rate to 400 mL / min, turn off the heating power supply and let it cool naturally. After cooling to room temperature, take out the specimen to obtain ZrC nanowires in-situ prepared in the low-density C / C composite material, as Figure 2 shown, Figure 2 (a) As can be seen from the morphology diagram, the obtained ZrC nanowires have a neat morphology. The ZrC nanowires are regular thin rod-shaped, with a large aspect ratio, and the diameter is about 100 nm( Figure 2 (b));

[0060] Figure 1XRD pattern of the ZrC nanowires prepared in Example 1 of the present invention. It can be seen that they have good crystallinity and no other impurity phases.

[0061] Example 2

[0062] A method for in-situ reaction preparation of ZrC nanowires in a composite material, comprising the following steps:

[0063] Step 1: The low-density C / C composite material with a density of 0.7 g / cm 3 and dimensions of 10 mm×10 mm×10 mm is successively polished with 400, 800, and 1000 grit sandpapers, ultrasonically cleaned with absolute ethanol for 0.5 h, and then placed in an oven at 70 °C for drying and standby;

[0064] Step 2: Weigh an appropriate amount of Ni(NO3)2 powder and put it into a beaker, pour in an appropriate amount of absolute ethanol, stir with a glass rod to prepare an ethanol solution of Ni(NO3)2 with a concentration of 0.1 mol / L. Mix the nano-zirconium sol and the Ni(NO3)2 solution according to a mass ratio of 2:1 to obtain a Ni(NO3)2 nano-zirconium sol;

[0065] Step 3: Put the low-density C / C composite material in Step 1 into a beaker containing the nano-zirconium Ni(NO3)2 solution, then put it into a vacuum impregnation box, turn on the vacuum pump, set the pressure to 100 Pa, keep the pressure for 10 min, take out the low-density C / C, and place it in an oven at 50 °C for drying;

[0066] Step 4: Hang the dried impregnated composite material at the deposition area position of the chemical vapor infiltration furnace, and put 60 g of ZrCl4 powder in the mold in the low-temperature area of the deposition furnace; turn on the vacuum pump and pump the furnace pressure down to 500 Pa, keep the pressure for 3 h;

[0067] Step 5: After the pressure holding is completed, turn on the vacuum pump, set the heating program, raise the temperature to 1200 °C in 2.5 h, and introduce Ar at a flow rate of 300 mL / min during the temperature rise;

[0068] Step 6: After reaching the temperature, introduce CH4 at 150 mL / min, Ar at 200 mL / min, and H2 at 350 mL / min, and keep the temperature for deposition for 2 h;

[0069] Step 7: After the deposition is completed, turn off CH4 and H2, adjust the Ar flow rate to 400 mL / min, turn off the heating power supply and let it cool naturally. After cooling to room temperature, take out the sample to obtain ZrC nanowires in-situ prepared on the low-density C / C composite material, as Figure 3 shown. It can be seen from the Figure 3 morphology diagram that the obtained ZrC nanowires grow uniformly in clusters, and their morphological characteristics are regular thin rod-like.

[0070] Example 3

[0071] A method for in-situ reaction preparation of ZrC nanowires in a composite material, comprising the following steps:

[0072] Step 1: The low-density C / C composite material with a density of 1.45 g / cm 3 and a size of 10 mm×10 mm×10 mm is successively polished with 400, 800, and 1000 grit sandpapers, ultrasonically cleaned with absolute ethanol for 0.5 h, and then placed in an oven at 70 °C for drying for later use;

[0073] Step 2: Weigh an appropriate amount of Ni(NO3)2 powder and put it into a beaker, pour in an appropriate amount of absolute ethanol, stir with a glass rod to prepare an ethanol solution of Ni(NO3)2 with a concentration of 0.15 mol / L. Mix the nano-zirconium sol and the Ni(NO3)2 solution according to a mass ratio of 15:1 to obtain a Ni(NO3)2 nano-zirconium sol;

[0074] Step 3: Put the low-density C / C composite material in Step 1 into a beaker containing the nano-zirconium Ni(NO3)2 solution, then put it into a vacuum impregnation box, turn on the vacuum pump, set the pressure to 100 Pa, keep the pressure for 10 min, take out the low-density C / C, and place it in an oven at 60 °C for drying;

[0075] Step 4: Hang the dried impregnated composite material at the deposition area position of the chemical vapor infiltration furnace, and put 60 g of ZrCl4 powder in the mold in the low-temperature area of the deposition furnace; turn on the vacuum pump, pump the furnace pressure down to 500 Pa, and keep the pressure for 3 h;

[0076] Step 5: After the pressure holding is completed, turn on the vacuum pump, set the heating program, raise the temperature to 1200 °C in 2.5 h, and introduce Ar at a flow rate of 300 mL / min during the temperature rise;

[0077] Step 6: After reaching the temperature, introduce CH4 at 200 mL / min, Ar at 200 mL / min, and H2 at 400 mL / min, and keep the temperature for deposition for 2 h;

[0078] Step 7: After the deposition is completed, turn off CH4 and H2, adjust the Ar flow rate to 200 mL / min, turn off the heating power supply and let it cool naturally. After cooling to room temperature, take out the sample to obtain ZrC nanowires in-situ prepared on the low-density C / C composite material. As Figure 4 shown, it can be seen from the Figure 4 morphology diagram that the obtained ZrC nanowires are regular thin rod-shaped with a large aspect ratio.

[0079] Example 4

[0080] A method for in-situ reaction preparation of ZrC nanowires in a composite material, comprising the following steps:

[0081] Step 1: The low-density C / C composite material with a density of 1.0 g / cm 3 , with dimensions of 10 mm × 10 mm × 10 mm, is successively polished with 400, 800, and 1000 grit sandpapers, ultrasonically cleaned with absolute ethanol for 0.5 h, and then placed in an oven at 70 °C for drying and standby;

[0082] Step 2: Weigh an appropriate amount of Ni(NO3)2 powder and put it into a beaker, pour in an appropriate amount of absolute ethanol, stir with a glass rod to prepare an ethanol solution of Ni(NO3)2 with a concentration of 0.1 mol / L. Mix the nano-zirconium sol and the Ni(NO3)2 solution according to a mass ratio of 10:1 to obtain the Ni(NO3)2 nano-zirconium sol;

[0083] Step 3: Put the low-density C / C composite material in Step 1 into a beaker containing the nano-zirconium Ni(NO3)2 solution, then put it into a vacuum impregnation box, turn on the vacuum pump, set the pressure to 100 Pa, keep the pressure for 10 min, take out the low-density C / C, and place it in an oven at 60 °C for drying;

[0084] Step 4: Hang the dried impregnated composite material at the deposition area position of the chemical vapor infiltration furnace, and put 100 g of ZrCl4 powder in the mold in the low-temperature area of the deposition furnace; turn on the vacuum pump and pump the furnace pressure down to 500 Pa, and keep the pressure for 3 h;

[0085] Step 5: After the pressure holding is completed, turn on the vacuum pump, set the heating program, heat up to 1100 °C in 2.5 h, and pass Ar at a flow rate of 300 mL / min during the heating;

[0086] Step 6: After reaching the temperature, pass CH4 at 200 mL / min, Ar at 200 mL / min, and H2 at 400 mL / min, and keep the temperature for deposition for 2 h;

[0087] Step 7: After the deposition is completed, turn off CH4 and H2, adjust the Ar flow rate to 400 mL / min, turn off the heating power supply and let it cool naturally. After cooling to room temperature, take out the sample to obtain ZrC nanowires prepared in-situ in the low-density C / C composite material.

[0088] Example 5

[0089] A method for in-situ reaction preparation of ZrC nanowires in a composite material, comprising the following steps:

[0090] Step 1: The low-density C / C composite material with a density of 0.6 g / cm 3, the low-density C / C composite material with a size of 10mm×10mm×10mm is polished successively with 400, 800, and 1000 grit sandpapers, ultrasonically cleaned with absolute ethanol for 1h, and then placed in an oven at 70°C for drying and standby;

[0091] Step 2: Weigh an appropriate amount of Ni(NO3)2 powder and put it into a beaker, pour in an appropriate amount of absolute ethanol, stir with a glass rod to prepare an ethanol solution of Ni(NO3)2 with a concentration of 0.5mol / L, and mix the nanozirconium sol and the Ni(NO3)2 solution according to a mass ratio of 5:1 to obtain the Ni(NO3)2 nanozirconium sol;

[0092] Step 3: Put the low-density C / C composite material in Step 1 into a beaker containing the nanozirconium Ni(NO3)2 solution, then put it into a vacuum impregnation box, turn on the vacuum pump, set the pressure to 100Pa, keep the pressure for 10min, take out the low-density C / C, and place it in an oven at 40°C for drying;

[0093] Step 4: Hang the dried impregnated composite material at the deposition area position of the chemical vapor infiltration furnace, and load 100g of ZrCl4 powder into the mold in the low-temperature area of the deposition furnace; turn on the vacuum pump and pump the furnace pressure down to 500Pa, and keep the pressure for 3h;

[0094] Step 5: After the pressure holding is completed, turn on the vacuum pump, set the heating program, heat up to 1150°C in 2.5h, and pass Ar at a flow rate of 300mL / min during the heating process;

[0095] Step 6: After reaching the temperature, pass CH4 at 100mL / min, Ar at 200mL / min, and H2 at 400mL / min, and keep the temperature for deposition for 2h;

[0096] Step 7: After the deposition is completed, turn off CH4 and H2, adjust the Ar flow rate to 400mL / min, turn off the heating power supply and let it cool naturally. After cooling to room temperature, take out the sample to obtain the ZrC nanowires in-situ prepared on the low-density C / C composite material.

[0097] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A method for in-situ reaction preparation of ZrC nanowires in a composite material, characterized in that, It includes the following steps: Immerse the low-density carbon-based or ceramic composite material in a metal salt zirconium sol for vacuum impregnation to obtain an impregnated composite material; After in-situ reaction by chemical vapor deposition in the impregnated composite material, ZrC nanowires are prepared.

2. The method for in-situ reaction preparation of ZrC nanowires in a composite material according to claim 1, characterized in that The density of the low-density carbon-based or ceramic composite material is 0.4 - 1.5 g / cm 3 ; The porosity of the low-density carbon-based or ceramic composite material is 30%-95%.

3. A method for in-situ reaction preparation of ZrC nanowires in a composite material according to claim 1, characterized in that, The metal salt zirconium sol is obtained by mixing a metal salt solution and a nano-zirconium sol; the metal salt solution is a Ni(NO3)2 solution, a NiCl2 solution, a NiSO4 solution, an FeCl3 solution, or an Fe2(SO4)3 solution; The mass ratio of the nano-metal sol to the metal salt solution is 2:1 to 20:

1.

4. A method for in-situ reaction preparation of ZrC nanowires in a composite material according to claim 3, characterized in that, The concentration of the metal salt solution is 0.1-3 mol / L.

5. A method for in-situ reaction preparation of ZrC nanowires in a composite material according to claim 1, characterized in that, The pressure of the vacuum impregnation is 50-100 Pa, and the pressure holding time is 10-20 min.

6. A method for in-situ reaction preparation of ZrC nanowires in a composite material according to claim 1, characterized in that, Before in-situ reaction by chemical vapor deposition to prepare ZrC nanowires, the impregnated composite material is dried; the drying temperature is 40-60 °C, and the time is 5-10 h.

7. A method for in-situ reaction preparation of ZrC nanowires in a composite material according to claim 1, characterized in that, The specific steps for in-situ reaction by chemical vapor deposition to prepare ZrC nanowires in the impregnated composite material are as follows: Suspend the impregnated composite material at the deposition area position of the chemical vapor infiltration furnace, load ZrCl4 powder in the deposition furnace mold, turn on the vacuum pump to evacuate, then set the heating program, after reaching the preset temperature, introduce hydrocarbon gas, Ar, and H2 for deposition, after the deposition is completed, turn off the hydrocarbon gas and H2, adjust the Ar flow rate, turn off the heating power supply and let it cool naturally, and take out the sample after cooling to room temperature to obtain ZrC nanowires prepared by in-situ reaction in the composite material.

8. A method for in-situ reaction preparation of ZrC nanowires in a composite material according to claim 7, characterized in that, The molar ratio of the ZrCl4 powder to the hydrocarbon gas is 5:1 to 10:1; The process parameters for evacuation are: pump the furnace pressure to 500-1000 Pa, hold the pressure for 3-5 h, after the pressure holding is completed, turn on the vacuum pump, and then set the heating program; The process parameters of the heating program are: heat up to 1100-1200 °C in 2-3 h, and introduce Ar at 300-500 mL / min during the heating period; The hydrocarbon gas is CH4, C3H6, or natural gas; The flow rates of the hydrocarbon gas, Ar, and H2 introduced are 100-300 mL / min, 200-600 mL / min, and 300-500 mL / min; the deposition time is 2-5 h; The adjusted Ar flow rate is 200-400 ml / min.

9. ZrC nanowires prepared by in-situ reaction in a composite material, characterized in that, Prepared by using the preparation method described in any one of claims 1-8.

10. Application of the ZrC nanowires prepared by in-situ reaction in the composite material described in claim 9 in ultra-high temperature ceramic modified C / C composite materials.

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