One component can be regulated (Hf) x ,Zr y C nanowires and their preparation methods

Abstract

This invention relates to a component-tunable (Hf) x ,Zr y SiC nanowires and their preparation method: The preparation method involves mixing ZrCl4 and HfCl4 powders in a predetermined ratio to obtain a mixed powder. The mixed powder is then placed in the powder sublimation zone of a chemical vapor deposition (CVD) furnace, and a SiC nanowire template is placed in the isothermal reaction zone of the CVD furnace. Using H2 as the reactant gas, Ar as the dilution gas, and ZrCl4 and HfCl4 as the Zr and Hf sources respectively, the nanowires are reacted under negative pressure. After the reaction is complete and the temperature drops to room temperature, (HfCl4) nanowires are obtained. x ,Zr y C nanowires, resulting in (Hf) x ,Zr y The composition of Hf2C nanowires is tunable, and compared with SiC nanowires, they exhibit strong high-temperature stability, maintaining their three-dimensional network structure even in an oxidizing atmosphere at 1700℃, and transforming in situ into Hf2C nanowires. x ,Zr y O2 nanowires. (Hf) prepared by this method x ,Zr y The synthesis of C nanowires involves low temperature, requires no catalyst, and exhibits stable and highly reproducible preparation processes. This method has broad applicability and can be extended to the preparation of refractory metal carbide mono- and multi-component solid solution nanowires.

Description

Technical Field

[0001] This invention belongs to the field of materials preparation technology, specifically relating to a template method for preparing Hf with controllable composition. x Zr y The method of C nanowires. Background Technology

[0002] One-dimensional ceramic nanowires possess high melting points, high strength, high modulus, and high aspect ratios, and are often used for toughening composite materials and ceramic coatings, showing strong application value in aerospace and other fields. Among them, SiC nanowires are currently the most widely used one-dimensional nanomaterials. However, in an oxidizing environment of at least 1700 °C, SiC nanowires will be oxidized into molten SiO2, thus losing their toughening effect.

[0003] Refractory metal carbides (HfC, ZrC, etc.) have high melting points, and their oxides also have high melting points. Therefore, their corresponding nanowires can still exhibit excellent toughening effects in high-temperature oxidizing environments. Furthermore, research shows that single-phase solid solution nanowires (HfC, ZrC, etc.) can also exhibit these effects. x Zr y Hf nanowires exhibit better high-temperature stability and mechanical properties compared to single-component nanowires. Patent 1, "Zhang Yulei, Zhang Jian. A Hf..." x Zr 1-x The paper "C Ceramic Solid Solution Nanowires and Preparation Method Thereof, CN202010821297.3[P], 2020" discloses a chemical vapor deposition method using Ni(NO3)2 as a catalyst to prepare Hf x Zr 1-xThe method of growing C nanowires requires the assistance of a catalyst during the nanowire growth process. Metal catalyst particles are present at the tip of the nanowires, leading to impurities within the nanowires. This impurity reduces the service performance of the toughened composite materials and coatings during high-temperature use. Reference 1, “MD Ma, XF Hu, H. Meng, et al. High-entropy metal carbidenanowires[J]. Cell Reports Physical Science, 2022, 3(4):100839,” describes the preparation of multi-component solid solution nanowires using a molten salt-assisted carbothermal reduction method. However, the nanowires prepared by this method are relatively short. The preparation process requires the use of both Fe(NO3)3 and Ni(NO3)2 catalysts. Furthermore, the products prepared by this method are mostly mixtures of particles and nanowires, making it difficult to obtain nanowires with high purity. Reference 2, "J. Zhao, Y. Zhang, H. Chen, et al. Single-source precursor derived high-entropy metal-carbide nanowires: Microstructure and growth evolution[J]. Journal of Advanced Ceramics, 2023,12(11):2041-2052," describes the preparation of multi-component solid solution nanowires using a precursor pyrolysis method. This method requires high nanowire preparation temperatures (1600~1700 ℃), resulting in short nanowires with poor dimensional uniformity, often exhibiting a bent and entangled shape. Furthermore, the complex reaction mechanisms during precursor preparation and pyrolysis lead to poor reproducibility of the nanowire preparation process. Therefore, to maximize the toughening effect of nanowires and promote their application in high-temperature oxygen-containing atmospheres, it is necessary to develop a nanowire preparation process with good stability, high reproducibility, simple component control, and wide applicability, and to prepare long, high-purity solid solution nanowires without catalysts. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a template method for preparing components with adjustable (Hf) x ,Zr y The method of C nanowires solves the problems of insufficient process stability, poor reproducibility, the need for catalysts in the preparation process, and the uneven size and short length of nanowires in the existing technology.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a component-tunable (Hf) x Zry The method for preparing C nanowires is characterized by comprising the following steps:

[0006] ZrCl4 and HfCl4 powders were mixed in a predetermined ratio to obtain a mixed powder. The mixed powder was then placed in the powder sublimation zone of a chemical vapor deposition (CVD) furnace, and the SiC nanowire template was placed in the isothermal reaction zone of the CVD furnace. Using H2 as the reactant gas, Ar as the dilution gas, and ZrCl4 and HfCl4 as the Zr and Hf sources respectively, the nanowires were reacted under negative pressure. After the reaction was completed and the temperature cooled to room temperature, (HfCl4) was obtained. x ,Zr y C nanowires.

[0007] Furthermore, SiC nanowire templates are prepared using chemical vapor deposition, thermal evaporation, polymer conversion, or sol-gel methods.

[0008] Furthermore, the preparation of SiC nanowire templates includes the following steps: mixing Si, SiO2 and C powders by ball milling in a set ratio, and then drying the mixed Si, SiO2 and C powders and placing them at the bottom of a graphite crucible;

[0009] The mold is placed in a mixture of Si, SiO2 and C powders. The cleaned and dried substrate is placed on top of the mold, and the crucible is sealed. Finally, the sealed crucible is heat-treated in an argon atmosphere for 2-4 hours. After the temperature drops to room temperature, SiC nanowires are obtained.

[0010] Furthermore, in the SiC nanowire template preparation process, the mass ratio of Si, SiO2 and C powder is 1:(2~5):(1~3).

[0011] Furthermore, the heat treatment temperature for preparing SiC nanowire templates is 1500℃-1700℃.

[0012] Furthermore, the purity of both ZrCl4 and HfCl4 powders is 99.9 wt%, and the particle size is 300 mesh; the molar ratio of ZrCl4 and HfCl4 powders is 1:30~10:1.

[0013] Furthermore, the preparation of (Hf) x Zr y The reaction temperature for C nanowires is 1300℃-1400℃, the reaction time is 2-4h, the Ar flow rate is 100~500mL / min, and the H2 flow rate is 500~1500mL / min.

[0014] Secondly, the present invention provides (Hf) as described above. x Zr yThe application of the C nanowire preparation method allows for the modification of reactant components to prepare monocomponent or multicomponent solid solution nanowires. Monocomponent solid solution nanowires are HfC nanowires, ZrC nanowires, or TaC nanowires. Multicomponent solid solution nanowires are (HfC nanowires, ZrC nanowires, or TaC nanowires). x Zr y , Ta z C nanowires, etc.

[0015] Thirdly, it provides a component with adjustable (Hf) x Zr y C nanowires, prepared using the above method, have a three-dimensional network structure.

[0016] It also provides adjustable (Hf) components. x Zr y The use of adding C nanowires to composite materials or coatings that are used in an oxidizing environment of not less than 1700°C to toughen the composite materials or coatings.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention proposes a template method for preparing components with adjustable (Hf) x Zr y The SiC nanowire method utilizes the reaction of active Zr and Hf atoms generated by the reaction of H2 with ZrCl4 and HfCl4 to react with SiC nanowires at high temperature. By adjusting the ratio of ZrCl4 and HfCl4 in the original powder, a composition with controllable Hf can be obtained. x Zr y HfC nanowires. The fabrication process for these nanowires is stable and highly reproducible; no catalyst is required, minimizing the introduction of impurities such as catalysts; the nanowires are uniform in size, with a diameter of approximately 200 nm and a length of several hundred micrometers. Compared to SiC nanowires, (HfC nanowires...) x Zr y SiC nanowires exhibit stronger high-temperature stability; after oxidation at 1700 °C for 30 min, the three-dimensional network structure of SiC nanowires disappears, and the resulting SiO2 glass undergoes melting and coalescence; while (Hf) x Zr y The C nanowires retain their three-dimensional network structure and are transformed in situ into (Hf) nanowires. x Zr y O2 nanowires, if (Hf) x Zr y Introducing C nanowires into composite materials or coatings, under oxidizing conditions at temperatures not lower than 1700 °C (Hf) x Zr yThe toughening effect of C nanowires on composite materials and coatings is superior to that of SiC nanowires. Furthermore, unlike the smooth surfaces of solid solution nanowires reported in the literature, the nanowires obtained in this invention have a rougher surface, which is expected to further improve the interfacial bonding strength between the nanowires and the matrix, thereby resulting in a superior toughening effect on composite materials or coatings. Attached Figure Description

[0018] Figure 1 For (Hf) x Zr y The XRD pattern of HfC nanowires. As shown in the figure, the diffraction peaks of the nanowires are located between the standard patterns of HfC and ZrC, and only one set of diffraction peaks exists, indicating that the nanowires obtained from the in-situ reaction are (HfC) nanowires. x Zr y C nanowires. Additionally, the C peak in the figure primarily originates from the carbon matrix.

[0019] Figure 2 For (Hf) x Zr y SEM images of the C nanowires. As shown in Figure (a), the nanowires obtained by the in-situ reaction are uniform in size, relatively long, and exhibit a three-dimensional network structure. Figure (b) shows that, unlike the smooth surfaces of nanowires reported in the literature, the nanowires prepared by this method have a rougher surface, which is expected to enhance the toughening effect on composite materials or coatings.

[0020] Figure 3 For SiC nanowires and (Hf x Zr y SEM images of SiC nanowires after oxidation at 1700 ℃ for 30 min. As shown in the figures, after oxidation at 1700 ℃ for 30 min, the SiC nanowires were oxidized to SiO2 and underwent melting and coalescence, losing their basic morphology and properties. This indicates that the stability of SiC nanowires in the 1700 ℃ oxidation environment is insufficient; while (Hf... x Zr y After oxidation for 30 min, the Hf nanowires still exhibit nanowire characteristics and maintain a three-dimensional network structure, indicating that the Hf nanowires prepared by this method... x ,Zr y C nanowires exhibit better stability in oxidizing atmospheres than SiC nanowires. Detailed Implementation

[0021] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0022] Example 1:

[0023] Si, SiO2, and C powders were weighed out in a mass ratio of 1:4:2 and ball-milled for 12 hours. The resulting powder was then dried in a 70 °C oven for 24 hours. The mixed powder was placed at the bottom of a graphite crucible, and a mold was placed inside. Cleaned and dried graphite paper (the substrate for nanowire growth) was placed on top of the mold. After placing the powder and substrate, the crucible was sealed and then heat-treated at 1600 °C in an argon atmosphere for 2 hours. After heat treatment, the power was turned off and the temperature was lowered to room temperature, yielding SiC nanowires used as templates.

[0024] In a glove box, ZrCl4 and HfCl4 powders were weighed out at a molar ratio of 1:1 and manually mixed for 30 min. The mixed powder was then placed in the sublimation zone of a chemical vapor deposition furnace, while the obtained SiC nanowires were suspended in the reaction isothermal zone using molybdenum wire. The vacuum pump was then turned on, and the furnace was pressure-maintained at 5 kPa. If the pressure remained constant after 30 min, the vacuum pump was turned on, and the temperature of the reaction zone was raised to 1300 ℃ at a heating rate of 5 ℃ / min, with an Ar flow rate of 200 mL / min. After reaching 1300 ℃, H2 was introduced at a flow rate of 1000 mL / min. After reacting for 4 h, the power was turned off and the temperature was lowered. Once the temperature reached room temperature, the nanowires were removed, yielding (HfCl4) nanowires. x Zr y C nanowires with a diameter of approximately 200 nm, wherein the Hf:Zr ratio is approximately 1:7.

[0025] Example 2:

[0026] Si, SiO2, and C powders were weighed out in a mass ratio of 1:5:2 and ball-milled for 12 hours. The resulting powder was then dried in a 70 °C oven for 24 hours. The mixed powder was placed at the bottom of a graphite crucible, and a mold was placed inside. A cleaned and dried C / C composite material (the substrate for nanowire growth) was placed on top of the mold. After placing the powder and substrate, the crucible was sealed and then heat-treated at 1700 °C in an argon atmosphere for 2 hours. After heat treatment, the power was turned off and the temperature was lowered to room temperature, yielding the SiC nanowires used as a template.

[0027] In a glove box, ZrCl4 and HfCl4 powders were weighed out at a molar ratio of 3:1 and manually mixed for 40 min. The mixed powder was then placed in the powder sublimation zone of a chemical vapor deposition furnace, while the obtained SiC nanowires were suspended in the reaction isothermal zone using molybdenum wire. The vacuum pump was then turned on, and the furnace was pressure-maintained at 5 kPa. If the pressure remained constant after 30 min, the vacuum pump was turned on, and the temperature of the reaction zone was raised to 1350 ℃ at a heating rate of 5 ℃ / min, with an Ar flow rate of 300 mL / min. After the temperature reached 1300 ℃, H2 was introduced at a flow rate of 1000 mL / min. After reacting for 4 h, the power was turned off and the temperature was lowered. Once the temperature reached room temperature, the nanowires were removed, yielding (HfCl4) nanowires. x Zr y C nanowires with a diameter of approximately 200 nm, wherein the Hf:Zr ratio is approximately 1:10.

[0028] Example 3:

[0029] Si, SiO2, and C powders were weighed out in a mass ratio of 1:4:3 and ball-milled for 12 hours. The resulting powder was then dried in a 70 °C oven for 24 hours. The mixed powder was placed at the bottom of a graphite crucible, and a mold was placed inside. Cleaned and dried graphite paper (the substrate for nanowire growth) was placed on top of the mold. After placing the powder and substrate, the crucible was sealed and then heat-treated at 1500 °C in an argon atmosphere for 4 hours. After heat treatment, the power was turned off and the temperature was lowered to room temperature, yielding SiC nanowires used as templates.

[0030] In a glove box, ZrCl4 and HfCl4 powders were weighed out at a molar ratio of 1:3 and manually mixed for 30 min. The mixed powder was then placed in the powder sublimation zone of a chemical vapor deposition furnace, while the obtained SiC nanowires were suspended in the reaction isothermal zone using molybdenum wire. The vacuum pump was then turned on, and the furnace was pressure-maintained at 5 kPa. If the pressure remained constant after 30 min, the vacuum pump was turned on again, and the temperature of the reaction zone was raised to 1300 ℃ at a heating rate of 5 ℃ / min, with an Ar flow rate of 300 mL / min. After reaching 1300 ℃, H2 was introduced at a flow rate of 1000 mL / min. After reacting for 4 h, the power was turned off and the temperature was lowered. Once the temperature reached room temperature, the nanowires were removed, yielding (HfCl4) nanowires. x Zr y C nanowires with a diameter of approximately 200 nm, wherein the Hf:Zr ratio is approximately 1:2.

[0031] Example 4:

[0032] Si, SiO2, and C powders were weighed out in a mass ratio of 1:5:2 and ball-milled for 12 hours. The resulting powder was then dried in a 70 °C oven for 24 hours. The mixed powder was placed at the bottom of a graphite crucible, and a mold was placed inside. Cleaned and dried graphite paper (the substrate for nanowire growth) was placed on top of the mold. After placing the powder and substrate, the crucible was sealed and then heat-treated at 1700 °C in an argon atmosphere for 2 hours. After heat treatment, the power was turned off and the temperature was lowered to room temperature, yielding SiC nanowires used as templates.

[0033] In a glove box, ZrCl4 and HfCl4 powders were weighed out at a molar ratio of 1:30 and manually mixed for 30 min. The mixed powder was then placed in the sublimation zone of a chemical vapor deposition furnace, while the obtained SiC nanowires were suspended in the reaction isothermal zone using molybdenum wire. The vacuum pump was then turned on, and the furnace was pressure-maintained at 5 kPa. If the pressure remained constant after 30 min, the vacuum pump was turned on again, and the temperature of the reaction zone was raised to 1300 ℃ at a heating rate of 5 ℃ / min, with an Ar flow rate of 100 mL / min. After reaching 1300 ℃, H2 was introduced at a flow rate of 1500 mL / min. After reacting for 4 h, the power was turned off and the temperature was lowered. Once the temperature reached room temperature, the nanowires were removed, yielding (HfCl4) nanowires. x Zr y C nanowires with a diameter of approximately 200 nm, wherein the Hf:Zr ratio is approximately 12:1.

[0034] Example 5:

[0035] Si, SiO2, and C powders were weighed out in a mass ratio of 1:4:3 and ball-milled for 12 hours. The resulting powder was then dried in a 70 °C oven for 24 hours. The mixed powder was placed at the bottom of a graphite crucible, and a mold was placed inside. Cleaned and dried graphite paper (the substrate for nanowire growth) was placed on top of the mold. After placing the powder and substrate, the crucible was sealed and then heat-treated at 1600 °C in an argon atmosphere for 2 hours. After heat treatment, the power was turned off and the temperature was lowered to room temperature, yielding SiC nanowires used as templates.

[0036] In a glove box, ZrCl4 and HfCl4 powders were weighed out at a molar ratio of 10:1 and manually mixed for 30 min. The mixed powder was then placed in the powder sublimation zone of a chemical vapor deposition furnace, while the obtained SiC nanowires were suspended in the reaction isothermal zone using molybdenum wire. The vacuum pump was then turned on, and the furnace was pressure-maintained at 5 kPa. If the pressure remained constant after 30 min, the vacuum pump was turned on, and the temperature of the reaction zone was raised to 1300 ℃ at a heating rate of 5 ℃ / min, with an Ar flow rate of 500 mL / min. After reaching 1300 ℃, H2 was introduced at a flow rate of 500 mL / min. After reacting for 4 h, the power was turned off and the temperature was lowered. Once the temperature reached room temperature, the nanowires were removed, yielding (HfCl4) nanowires. x Zr y C nanowires with a diameter of approximately 200 nm, wherein the Hf:Zr ratio is approximately 1:14.

[0037] Example 6:

[0038] Si, SiO2, and C powders were weighed out in a mass ratio of 1:4:2 and ball-milled for 12 hours. The resulting powder was then dried in a 70 °C oven for 24 hours. The mixed powder was placed at the bottom of a graphite crucible, and a mold was placed inside. Cleaned and dried graphite paper (the substrate for nanowire growth) was placed on top of the mold. After placing the powder and substrate, the crucible was sealed and then heat-treated at 1600 °C in an argon atmosphere for 2 hours. After heat treatment, the power was turned off and the temperature was lowered to room temperature, yielding SiC nanowires used as templates.

[0039] In a glove box, ZrCl4 and HfCl4 powders were weighed out at a molar ratio of 1:1 and manually mixed for 30 min. The mixed powder was then placed in the sublimation zone of a chemical vapor deposition furnace, while the obtained SiC nanowires were suspended in the reaction isothermal zone using molybdenum wire. The vacuum pump was then turned on, and the furnace was pressure-maintained at 5 kPa. If the pressure remained constant after 30 min, the vacuum pump was turned on again, and the temperature of the reaction zone was raised to 1400 ℃ at a heating rate of 5 ℃ / min, with an Ar flow rate of 200 mL / min. After reaching 1400 ℃, H2 was introduced at a flow rate of 1000 mL / min. After reacting for 2 h, the power was turned off and the temperature was lowered. Once the temperature reached room temperature, the nanowires were removed, yielding (HfCl4) nanowires. x Zr y C nanowires with a diameter of approximately 200 nm, wherein the Hf:Zr ratio is approximately 1:2.

[0040] Comparative Example 1:

[0041] The difference between this comparative example and the aforementioned embodiments is that the reaction temperature of the nanowires is lower, and the nanowires were not completely dissolved to form (Hf). x Zr y SiC nanowires were prepared by weighing Si, SiO2, and C powders in a mass ratio of 1:4:2 and ball-milling them for 12 hours. The resulting powders were then dried in a 70°C oven for 24 hours. The mixed powder was placed at the bottom of a graphite crucible, and a mold was placed inside. Cleaned and dried graphite paper (the substrate for nanowire growth) was placed on top of the mold. After placing the powder and substrate, the crucible was sealed and then heat-treated at 1600°C in an argon atmosphere for 2 hours. After heat treatment, the power was turned off and the temperature was lowered to room temperature to obtain the SiC nanowires used as templates.

[0042] In a glove box, ZrCl4 and HfCl4 powders were weighed out at a molar ratio of 1:3 and manually mixed for 30 min. The mixed powder was then placed in the sublimation zone of a chemical vapor deposition furnace, while the obtained SiC nanowires were suspended in the reaction isothermal zone using molybdenum wire. The vacuum pump was then turned on, and the furnace was pressure-maintained at 5 kPa. If the pressure remained constant after 30 min, the vacuum pump was turned on again, and the temperature of the reaction zone was increased to 1200 ℃ at a heating rate of 5 ℃ / min, with an Ar flow rate of 200 mL / min. After the temperature reached 1300 ℃, H2 was introduced at a flow rate of 1000 mL / min. After 4 h of reaction, the power was turned off and the temperature was lowered. Once the temperature reached room temperature, the nanowires were removed. The obtained nanowires were not (HfCl4)... x Zr y C nanowires, but made of Hf x Si y Zr x Si y Nanowires composed of a mixture of phases such as HfC.

[0043] Comparative Example 2:

[0044] The difference between this comparative example and the previous embodiment lies in the insufficient H2 content during nanowire preparation, resulting in a higher content of silicides in the nanowires. Si, SiO2, and C powders were weighed in a mass ratio of 1:4:2 and ball-milled for 12 hours. The resulting powder was then dried in a 70°C oven for 24 hours. The mixed powder was placed at the bottom of a graphite crucible, and a mold was placed inside. Cleaned and dried graphite paper (the substrate for nanowire growth) was placed on top of the mold. After placing the mixed powder and substrate, the crucible was sealed and then heat-treated in an argon atmosphere at 1700°C for 2 hours. After heat treatment, the power was turned off and the temperature was lowered to room temperature, yielding SiC nanowires used as templates.

[0045] ZrCl4 and HfCl4 powders were weighed in a glove box at a molar ratio of 1:1 and manually mixed for 30 min. The mixed powder was then placed in the powder sublimation zone of a chemical vapor deposition furnace, while the obtained SiC nanowires were suspended in the reaction isothermal zone using molybdenum wire. The vacuum pump was then turned on, and the furnace was pressure-maintained at 5 kPa. If the pressure remained constant after 30 min, the vacuum pump was turned on again, and the temperature of the reaction zone was raised to 1300 ℃ at a heating rate of 5 ℃ / min, with an Ar flow rate of 100 mL / min. After reaching 1300 ℃, H2 was introduced at a flow rate of 100 mL / min. After reacting for 4 h, the power was turned off and the temperature was lowered. Once the temperature reached room temperature, the nanowires were removed, yielding (HfCl4) nanowires. x Zr y In C nanowires, besides containing (Hf) x Zr y In addition to C, there is also Hf. x Si y Zr x Si y .

[0046] refer to Figure 1 The diffraction peaks of the nanowires are located between the standard spectra of HfC and ZrC, and there is only one set of diffraction peaks, indicating that the nanowires obtained by the in-situ reaction are (HfC)-ZrC ... x Zr y C nanowires. Additionally, Figure 1 The C peak in the reference image mainly originates from the carbon matrix; Figure 2 As shown (Hf) x Zr y SEM image of C nanowires. (Source: [Original Source Name]) Figure 2As shown in Figure (a), the nanowires obtained by the in-situ reaction are uniform in size, relatively long, and exhibit a three-dimensional network structure. Figure (b) shows that, unlike the smooth surfaces of nanowires reported in the literature, the nanowires prepared by this method have a rougher surface, which is expected to enhance the toughening effect on composite materials or coatings; Reference Figure 3 The SiC nanowires and (Hf) shown x Zr y SEM images of SiC nanowires after oxidation at 1700 ℃ for 30 min. As shown in the figures, after oxidation at 1700 ℃ for 30 min, the SiC nanowires were oxidized to SiO2 and underwent melting and coalescence, losing their basic morphology and properties. This indicates that the stability of SiC nanowires in the 1700 ℃ oxidation environment is insufficient; while (Hf... x Zr y After oxidation for 30 min, the Hf nanowires still exhibit nanowire characteristics and maintain a three-dimensional network structure, indicating that the Hf nanowires prepared by this method... x Zr y C nanowires exhibit better stability in oxidizing atmospheres than SiC nanowires.

[0047] This invention provides a template method for preparing (Hf) x Zr y The method involves preparing SiC nanowires. First, a SiC nanowire template is prepared using thermal evaporation. Then, a chemical vapor deposition method is used to react the active Zr and Hf atoms generated from the reaction of ZrCl4 and HfCl4 with H2 with the SiC nanowires, converting the SiC nanowires into (HfCl4) nanowires. x Zr y C nanowires. (Hf) nanowires prepared by the above method. x Zr y The composition of Hf2C nanowires is tunable, and compared with SiC nanowires, they exhibit strong high-temperature stability, maintaining their three-dimensional network structure even in an oxidizing atmosphere at 1700 °C, and transforming in situ into Hf2C nanowires. x Zr y O2 nanowires. (Hf) prepared by this method x Zr y The synthesis of C nanowires involves low temperature, requires no catalyst, and exhibits stable and highly reproducible preparation processes. This method has broad applicability and can be extended to the preparation of refractory metal carbide mono- and multi-component solid solution nanowires.

[0048] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A component that can be regulated (Hf) x Zr y The method for preparing C nanowires is characterized by, Includes the following steps: ZrCl4 and HfCl4 powders were mixed in a predetermined ratio to obtain a mixed powder. The mixed powder was then placed in the powder sublimation zone of a chemical vapor deposition (CVD) furnace, and the SiC nanowire template was placed in the isothermal reaction zone of the CVD furnace. Using H2 as the reactant gas, Ar as the dilution gas, and ZrCl4 and HfCl4 as the Zr and Hf sources respectively, the nanowires were reacted under negative pressure. After the reaction was completed and the temperature cooled to room temperature, (HfCl4) was obtained. x ,Zr y C nanowires; preparation of (Hf) nanowires x Zr y The reaction temperature for C nanowires is 1300℃-1400℃, the reaction time is 2-4h, the Ar flow rate is 100~500mL / min, and the H2 flow rate is 500~1500mL / min.

2. The component is tunable (Hf) according to claim 1 x Zr y The method for preparing C nanowires is characterized by, SiC nanowire templates were prepared using chemical vapor deposition, thermal evaporation, polymer conversion, or sol-gel methods.

3. The component is tunable (Hf) according to claim 1 x Zr y The method for preparing C nanowires is characterized by, The preparation of SiC nanowire templates includes the following steps: Si, SiO2 and C powders are ball-milled and mixed in a set ratio, and the mixed Si, SiO2 and C powders are dried and placed at the bottom of a graphite crucible; The mold is placed in a mixture of Si, SiO2 and C powders. The cleaned and dried substrate is placed on top of the mold, and the crucible is sealed. Finally, the sealed crucible is heat-treated in an argon atmosphere for 2-4 hours. After the temperature drops to room temperature, SiC nanowires are obtained.

4. The component is tunable (Hf) according to claim 1 x Zr y The method for preparing C nanowires is characterized by, When preparing SiC nanowire templates, the thermal evaporation method is used, and the mass ratio of Si, SiO2 and C powder is 1:(2~5):(1~3).

5. The component is tunable (Hf) according to claim 1 x Zr y The method for preparing C nanowires is characterized by, The heat treatment temperature for preparing SiC nanowire templates is 1500℃-1700℃.

6. The component is tunable (Hf) according to claim 1 x Zr y The method for preparing C nanowires is characterized by, The purity of both ZrCl4 and HfCl4 powders is 99.9 wt%, and the particle size is 300 mesh; the molar ratio of ZrCl4 and HfCl4 powders is 1:30~10:

1.

7. The (Hf) as described in any one of claims 1-6 x Zr y The application of the C nanowire preparation method is characterized by, By changing the reactant composition, monocomponent or multicomponent solid-solution nanowires can be prepared. The monocomponent solid-solution nanowires can be HfC nanowires, ZrC nanowires, or TaC nanowires, while the multicomponent solid-solution nanowires can be (HfC, ZrC, or TaC nanowires). x Zr y , Ta z C nanowires.

8. A component with adjustable properties (Hf) x ,Zr y C nanowires, characterized in that, The structure obtained by the preparation method described in any one of claims 1-6 is a three-dimensional network structure.

9. The component tunable (Hf) of claim 8 x Zr y The application of C nanowires is characterized by, Used to incorporate into composite materials or coatings that operate in oxidizing environments of not less than 1700°C and to toughen the composite materials or coatings.

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