阅读说明：本技术 碳化硅纳米线的合成方法 (Synthesis method of silicon carbide nanowire ) 是由 李季 刘杰 张磊 杨春晖 于 2019-10-31 设计创作，主要内容包括：碳化硅纳米线的合成方法,它涉及一种碳化硅纳米线的合成方法。本发明是为了解决现有制备碳化硅纳米线的方法原材料浪费严重、成本高、结构不均匀、长径比低的技术问题。本方法如下：将处理后的生长基底放于坩埚内硅树脂的上方,将坩埚放于真空高温炉中在升温,保温,降温,即得。该方法在生长SiC纳米线的同时,在模具内部生成SiC纳米颗粒,这样可以极大的提高原料利用率从而降低了成本,同时合成了链珠状的SiC纳米线,特殊的链珠状结构使其在复合材料、场致发射体、光催化剂、储氢及疏水表面具有更大的应用潜力。链珠状纳米线的生成同时伴有超长超直的SiC纳米线的生成。产品结构均匀。本发明属于纳米线的制备领域。(A method for synthesizing silicon carbide nano-wires relates to a method for synthesizing silicon carbide nano-wires. The invention aims to solve the technical problems of serious raw material waste, high cost, uneven structure and low length-diameter ratio of the existing method for preparing the silicon carbide nanowire. The method comprises the following steps: and placing the treated growth substrate above the silicon resin in the crucible, placing the crucible in a vacuum high-temperature furnace, heating, preserving heat and cooling to obtain the silicon-based growth substrate. The method can greatly improve the utilization rate of raw materials so as to reduce the cost while growing the SiC nanowires and generate SiC nanoparticles in the die, and the special chain bead-shaped structure ensures that the SiC nanowires have greater application potential in composite materials, field emitters, photocatalysts, hydrogen storage and hydrophobic surfaces. The generation of the chain bead-shaped nanowire is simultaneously accompanied with the generation of the overlong and overlong SiC nanowire. The product structure is uniform. The invention belongs to the field of preparation of nanowires.)

1. The synthesis method of the silicon carbide nanowire is characterized by comprising the following steps of:

firstly, weighing silicon resin and a metal catalyst, and putting the silicon resin into a crucible;

dissolving a metal catalyst by using absolute ethyl alcohol, wherein the concentration of the catalyst is 0.01-0.2mol/L, and obtaining a metal salt solution;

respectively cleaning the growth substrate with distilled water and ethanol, drying in vacuum, putting the dried growth substrate in a metal salt solution, soaking for 30min-2h at 20 ℃ under vacuum, and then drying the soaked growth substrate at 60-80 ℃ under vacuum;

fourthly, the growth substrate processed in the third step is placed above the silicon resin in the crucible, the crucible is placed in a vacuum high-temperature furnace, under the conditions that the heating rate is 1-10 ℃/min and the argon protection is carried out, the temperature is raised to 1300-1700 ℃, the temperature is kept for 1-5h, the temperature is lowered, the temperature lowering rate is set to be two hours and is lowered to 1000 ℃, and then the silicon carbide nanowire is obtained after natural cooling to the room temperature.

2. The method for synthesizing silicon carbide nanowires according to claim 1, wherein the silicone resin in step one is polymethylsilsesquioxane, methylphenylsilicone, methylsilicone, low-phenyl methylsilicone, self-drying silicone, high-temperature silicone, epoxy-modified silicone, silicone polyester-modified resin, self-drying environment-friendly silicone, non-stick coating MQ material silicone, high-gloss silicone, benzyl transparent silicone, methyl transparent silicone, mica-bonded silicone, polymethylsilicone, amino silicone, fluorosilicone, silicone-epoxy, silicone polyester, solvent-resistant silicone, silicone adhesive, high-temperature-resistant methylsilicone, methyl MQ silicone or vinyl silicone.

3. The method for synthesizing silicon carbide nanowires of claim 1, wherein the metal catalyst in the first step is Fe (CO)₅、Fe₂(CO)₉、Fe(C₅H₅)、Fe₃O₄、FeCl₂、FeCl₂·6H₂O、FeCl₃、FeCl₃·6H₂O、Fe(NO)₂、Fe(NO)₃、Fe₂O₃、NiCl₂、NiBr₂、NiI₂、NiO、Ni(OH)₂、(C₂H₅)₂Ni、Ni(CO)₄、Ni(NO₃)₂、CuCl₂、Cu(NO₃)₂、C₂₂H₁₄CuO₄、Cu₂O、Mn(NO₃)₂、(C₁₇H₃₅COO)₂Mn、PdCl₂、Y₂O₃、DyCl₃、CoC₂O₄、CoCO₃、CoO、CoCl₂、Co(OH)₂、Co(NH₃)₆、Co(CN)₆、Co(SCN)₄、Co(CO)₄、Co(NO₃)₂。

4. The method for synthesizing silicon carbide nanowires according to claim 1, wherein the crucible of step one is a corundum crucible, a graphite crucible, a quartz crucible, a platinum crucible, an alumina crucible, a platinum crucible, a molybdenum crucible, or a silicon carbide crucible;

step three, the growth substrate is graphite felt, carbon fiber, carbon cloth, SiC fiber cloth, SiC single crystal wafer, graphite sheet and SiO₂Fibers, alumina silicate fibers, glass fibers, mullite sheets, alumina fibers, zirconia fibers, polyimide fibers, aramid fibers, Si nanowires, or Al₂O₃。

5. The method for synthesizing silicon carbide nanowires according to claim 1, wherein the crucible is placed in a vacuum high temperature furnace and heated up at an argon flow rate of 0.2ml/min in the fourth step, wherein the heating rate is 3 ℃/min before reaching 600 ℃, and the temperature is raised to 1400 ℃ at 5 ℃/min after reaching 600 ℃, and then raised to 1550 ℃ at a heating rate of 1 ℃/min, and the temperature is maintained at 1550 ℃ for 3 hours, and then the temperature is lowered, and the temperature is lowered to 1000 ℃ two hours, and then the crucible is naturally cooled to room temperature.

6. The synthesis method of the silicon carbide nanowire is characterized by comprising the following steps of:

weighing silicon resin and a metal catalyst, mixing to obtain a mixture, wherein the mass fraction of the metal catalyst in the mixture is 1-10%, and putting the mixture into a crucible;

and secondly, respectively cleaning the growth substrate by using distilled water and ethanol, drying the growth substrate in vacuum at the temperature of 20-60 ℃, placing the dried growth substrate on the mixture in the crucible, then placing the crucible in a vacuum high-temperature furnace, heating the crucible to 1300-1700 ℃ under the conditions of heating rate of 1-10 ℃/min and argon protection, preserving the temperature for 1-5h, cooling the crucible, setting the cooling rate for two hours, cooling the temperature to 1000 ℃, and naturally cooling the crucible to room temperature to obtain the silicon carbide nanowire.

7. The method for synthesizing silicon carbide nanowires according to claim 6, wherein the silicone resin in step one is polymethylsilsesquioxane, methylphenylsiloxane, methylsilane, low-phenyl methylsiloxane, self-drying silicone, high-temperature silicone, epoxy-modified silicone, silicone polyester-modified resin, self-drying environment-friendly silicone, non-stick coating MQ silicone, high-gloss silicone, benzyl transparent silicone, methyl transparent silicone, mica-bonded silicone, polymethylsilicone, amino silicone, fluorosilicone, silicone-epoxy, silicone polyester, solvent-resistant silicone, silicone adhesive, high-temperature-resistant methylsilane, methyl MQ silicone, or vinyl silicone;

step one, the metal catalyst is Fe (CO)₅、Fe₂(CO)₉、Fe(C₅H₅)、Fe₃O₄、FeCl₂、FeCl₂·6H₂O、FeCl₃、FeCl₃·6H₂O、Fe(NO)₂、Fe(NO)₃、Fe₂O₃、NiCl₂、NiBr₂、NiI₂、NiO、Ni(OH)₂、(C₂H₅)₂Ni、Ni(CO)₄、Ni(NO₃)₂、CuCl₂、Cu(NO₃)₂、C₂₂H₁₄CuO₄、Cu₂O、Mn(NO₃)₂、(C₁₇H₃₅COO)₂Mn、PdCl₂、Y₂O₃、DyCl₃、CoC₂O₄、CoCO₃、CoO、CoCl₂、Co(OH)₂、Co(NH₃)₆、Co(CN)₆、Co(SCN)₄、Co(CO)₄、Co(NO₃)₂；

Step one, the crucible is a corundum crucible, a graphite crucible, a quartz crucible, a platinum crucible, an alumina crucible, a platinum crucible, a molybdenum crucible or a silicon carbide crucible;

the growth substrate in the second step is graphite felt, carbon fiber, carbon cloth, SiC fiber cloth, SiC single crystal wafer, graphite sheet and SiO₂Fibers, alumina silicate fibers, glass fibers, mullite sheets, alumina fibers, zirconia fibers, polyimide fibers, aramid fibers, Si nanowires, or Al₂O₃。

8. The method for synthesizing silicon carbide nanowires according to claim 6, wherein in the second step, the crucible is placed in a vacuum high-temperature furnace, the temperature is raised under the condition that the flow rate of argon gas is 0.2ml/min, wherein the temperature raising rate is 3 ℃/min before reaching 600 ℃, the temperature is raised to 1000 ℃ at 5 ℃/min after reaching 600 ℃, the temperature is kept at 1000 ℃ for 15min, then the temperature is raised to 1650 ℃ at the temperature raising rate of 3 ℃/min, the temperature is kept at 1650 ℃ for 3h, then the temperature is reduced, the temperature reduction rate is set to two hours, the temperature is reduced to 1000 ℃, and then the crucible is naturally cooled to room temperature.

9. The method for synthesizing silicon carbide nanowires of claim 16, wherein in the second step, the crucible is placed in a vacuum high temperature furnace, and the temperature is raised at an argon flow rate of 0.2ml/min, wherein the temperature raising rate is 3 ℃/min before reaching 600 ℃, the temperature is raised to 1400 ℃ at 5 ℃/min after reaching 600 ℃, the temperature is maintained at 1400 ℃ for 15min, then the temperature is raised to 1500 ℃ at a temperature raising rate of 3 ℃/min, the temperature is maintained at 1500 ℃ for 3h, then the temperature is lowered, the temperature lowering rate is set to two hours, the temperature is lowered to 1000 ℃, and the crucible is naturally cooled to room temperature.

10. The method for synthesizing silicon carbide nanowires according to claim 6, wherein the crucible in the second step is placed in a vacuum high temperature furnace, and the temperature is raised under the condition that the flow rate of argon gas is 0.2ml/min, wherein the temperature raising rate is 3 ℃/min before reaching 600 ℃, the temperature is raised to 1400 ℃ at 5 ℃/min after reaching 600 ℃, the temperature is maintained at 1400 ℃ for 180min, and then the temperature is lowered, the temperature lowering rate is set to be two hours, the temperature is lowered to 1000 ℃, and the crucible is naturally cooled to the room temperature.

Technical Field

The invention relates to a method for synthesizing a silicon carbide nanowire.

Background

Silicon carbide as a third-generation semiconductor material has characteristics such as a wide band gap, high thermal conductivity, large electron saturation mobility, and good chemical stability, compared with a first-generation semiconductor represented by a silicon semiconductor and a second-generation semiconductor represented by a gallium arsenide (GaAs) semiconductor. Has good conductivity, toughness, high temperature resistance, corrosion resistance, abrasion resistance, radiation resistance and other properties. In addition to the above properties, one-dimensional (1D) SiC nanomaterials, which exhibit unique mechanical, electrical and optical properties, have attracted considerable attention from a large number of researchers, have found widespread use in composites, field emitters, optical circuits, light emitting diodes, photocatalysts, hydrogen storage and hydrophobic surfaces. The breaking strength of the SiC nanowire is far greater than that of bulk SiC and micron-sized SiC whiskers, so that the SiC nanowire has more excellent performance in application to composite materials.

At present, a plurality of methods for synthesizing the silicon carbide nanowires are available, and mainly comprise a carbothermic method, a template growth method, a chemical vapor deposition method and the like. The major mechanisms for synthesizing silicon carbide whiskers include a VLS mechanism and a VL mechanism, and the major differences are that the VLS method uses a catalyst with appropriate composition and performance, so that the nanowires grow at a high speed and at a low temperature, which causes a problem that the product needs to be subjected to a one-step catalyst separation operation. In contrast, the VL reaction mechanism has a slow growth rate and a high growth temperature, which has the advantage that the product is relatively pure without the need for catalyst separation. The research shows that two growth mechanisms of VLS and VL exist in the growth process of the nanowire added with the metal catalyst. As it is found in SEM electron micrographs, the phenomenon of no metal droplets at the nanowire tips occurs.

At present, the growth of the nanowire is still in a laboratory stage for various reasons, the problems of small length-diameter ratio, uneven morphology and structure and the like generally exist in the SiC nanowire synthesized by researchers at present, the growth of the nanowire is mostly carried out by adopting a gas phase method at present, the yield is low, the residual raw material slag for growing the SiC nanowire cannot be well applied, the raw material waste is serious, and the economic cost is high. Which makes the industrialization promotion difficult.

Disclosure of Invention

The invention aims to solve the technical problems of serious raw material waste, high cost, non-uniform structure and low length-diameter ratio of the existing method for preparing the silicon carbide nanowire, and provides a method for synthesizing the silicon carbide nanowire.

The synthesis method of the silicon carbide nanowire comprises the following steps:

firstly, weighing silicon resin and a metal catalyst, and putting the silicon resin into a crucible;

dissolving a metal catalyst by using absolute ethyl alcohol, wherein the concentration of the catalyst is 0.01-0.2mol/L, and obtaining a metal salt solution;

respectively cleaning the growth substrate with distilled water and ethanol, drying in vacuum, putting the dried growth substrate in a metal salt solution, soaking for 30min-2h at 20 ℃ under vacuum, and then drying the soaked growth substrate at 60-80 ℃ under vacuum;

fourthly, the growth substrate processed in the third step is placed above the silicon resin in the crucible, the crucible is placed in a vacuum high-temperature furnace, under the conditions that the heating rate is 1-10 ℃/min and the argon protection is carried out, the temperature is raised to 1300-1700 ℃, the temperature is kept for 1-5h, the temperature is lowered, the temperature lowering rate is set to be two hours and is lowered to 1000 ℃, and then the silicon carbide nanowire is obtained after natural cooling to the room temperature.

The silicone resin is polymethyl silsesquioxane, methyl phenyl silicone resin, methyl silicone resin, low phenyl methyl silicone resin, self-drying silicone resin, high-temperature silicone resin, epoxy modified silicone resin, silicone polyester modified resin, self-drying environment-friendly silicone resin, non-stick coating MQ material silicone resin, highlight silicone resin, benzyl transparent silicone resin, methyl transparent silicone resin, mica bonding silicone resin, polymethyl silicone resin, amino silicone resin, fluorosilicone resin, silicone-epoxy resin, silicone polyester resin, solvent-resistant silicone resin, silicone resin adhesive, high-temperature-resistant methyl silicone resin, methyl MQ silicone resin or vinyl MQ silicone resin.

Step one, the metal catalyst is Fe (CO)₅、Fe₂(CO)₉、Fe(C₅H₅)、Fe₃O₄、FeCl₂、FeCl₂·6H₂O、FeCl₃、FeCl₃·6H₂O、Fe(NO)₂、Fe(NO)₃、Fe₂O₃、NiCl₂、NiBr₂、NiI₂、NiO、Ni(OH)₂、(C₂H₅)₂Ni、Ni(CO)₄、Ni(NO₃)₂、CuCl₂、Cu(NO₃)₂Copper naphthenate C₂₂H₁₄CuO₄、Cu₂O、Mn(NO₃)₂Manganese stearate (C)₁₇H₃₅COO)₂Mn、PdCl₂、Y₂O₃、DyCl₃、CoC₂O₄、CoCO₃、CoO、CoCl₂、Co(OH)₂、Co(NH₃)₆、Co(CN)₆、Co(SCN)₄、Co(CO)₄、Co(NO₃)₂。

Step one, the crucible is a corundum crucible, a graphite crucible, a quartz crucible, a platinum crucible, an alumina crucible, a platinum crucible, a molybdenum crucible or a silicon carbide crucible;

step three, the growth substrate is graphite felt, carbon fiber, carbon cloth, SiC fiber cloth, SiC single crystal wafer, graphite sheet and SiO₂Fibers, alumina silicate fibers, glass fibers, mullite sheets, alumina fibers, zirconia fibers, polyimide fibers, aramid fibers, Si nanowires, or Al₂O₃。

The synthesis method of the silicon carbide nanowire comprises the following steps:

weighing silicon resin and a metal catalyst, mixing to obtain a mixture, wherein the mass fraction of the metal catalyst in the mixture is 1-10%, and putting the mixture into a crucible;

and secondly, respectively cleaning the growth substrate by using distilled water and ethanol, drying the growth substrate in vacuum at the temperature of 20-60 ℃, placing the dried growth substrate on the mixture in the crucible, then placing the crucible in a vacuum high-temperature furnace, heating the crucible to 1300-1700 ℃ under the conditions of heating rate of 1-10 ℃/min and argon protection, preserving the temperature for 1-5h, cooling the crucible, setting the cooling rate for two hours, cooling the temperature to 1000 ℃, and naturally cooling the crucible to room temperature to obtain the silicon carbide nanowire.

Step one, the silicon resin is polymethyl silsesquioxane, methyl phenyl silicon resin, methyl silicon resin, low phenyl methyl silicon resin, self-drying type organic silicon resin, high-temperature type organic silicon resin, epoxy modified organic silicon resin, organic silicon polyester modified resin, self-drying type environment-friendly organic silicon resin, non-stick coating MQ material organic silicon resin, highlight organic silicon resin, benzyl transparent silicon resin, methyl transparent organic silicon resin, mica bonding silicon resin, polymethyl silicon resin, amino silicon resin, fluorine silicon resin, organic silicon-epoxy resin, organic silicon polyester resin, solvent-resistant type organic silicon resin, organic silicon resin adhesive, high-temperature resistant methyl silicon resin, methyl MQ silicon resin or vinyl MQ silicon resin;

step one, the metal catalyst is Fe (CO)₅、Fe₂(CO)₉、Fe(C₅H₅)、Fe₃O₄、FeCl₂、FeCl₂·6H₂O、FeCl₃、FeCl₃·6H₂O、Fe(NO)₂、Fe(NO)₃、Fe₂O₃、NiCl₂、NiBr₂、NiI₂、NiO、Ni(OH)₂、(C₂H₅)₂Ni、Ni(CO)₄、Ni(NO₃)₂、CuCl₂、Cu(NO₃)₂Copper naphthenate C₂₂H₁₄CuO₄、Cu₂O、Mn(NO₃)₂Manganese stearate (C)₁₇H₃₅COO)₂Mn、PdCl₂、Y₂O₃、DyCl₃、CoC₂O₄、CoCO₃、CoO、CoCl₂、Co(OH)₂、Co(NH₃)₆、Co(CN)₆、Co(SCN)₄、Co(CO)₄、Co(NO₃)₂；

Step one, the crucible is a corundum crucible, a graphite crucible, a quartz crucible, a platinum crucible, an alumina crucible, a platinum crucible, a molybdenum crucible or a silicon carbide crucible;

step two, the growth substrate is graphite felt, carbon fiber, carbon cloth, SiC fiber cloth and SiC single crystal waferGraphite flake and SiO₂Fibers, alumina silicate fibers, glass fibers, mullite sheets, alumina fibers, zirconia fibers, polyimide fibers, aramid fibers, Si nanowires, or Al₂O₃。

The principle of the invention is that the high polymerization degree silicon resin is cracked under the high temperature condition to generate gases such as SiO, CO and the like, the metal salt is gasified under the high temperature condition, the reducing gases such as CO, SiO and the like reduce metal ions into simple substance metal, the metal is in a liquid state under the high temperature condition, liquid metal drops continuously absorb CO (g), SiO (g) and Si (g) in a system, and the gas absorbed on the metal drops reacts to generate SiC nano wires. According to the invention, by reasonably adjusting the raw material proportion and the temperature condition, the growth of SIC nanowires with special shapes is realized, and silicon carbide particles with uniform particle sizes are prepared at the bottom of the die. The invention is expected to be produced in industrialization. And the special appearance of the SiC nanowire can ensure that the SiC nanowire is expected to show more excellent performances on composite materials, field emitters, photocatalysts, hydrogen storage and hydrophobic surfaces.

The invention aims to provide a method for preparing a silicon carbide nanowire, which can generate SiC nanoparticles in a die while growing the SiC nanowire, so that the utilization rate of raw materials can be greatly improved, the cost is reduced, and a good prospect is brought to popularization of the SiC nanowire. Meanwhile, the chain bead-shaped SiC nanowire is synthesized, and the special chain bead-shaped structure enables the SiC nanowire to have greater application potential in composite materials, field emitters, photocatalysts, hydrogen storage and hydrophobic surfaces. The generation of the chain bead-shaped nanowire is simultaneously accompanied with the generation of the overlong and overlong SiC nanowire. The product has uniform structure, and has more excellent application potential in composite materials, field emitters, optical circuits, light-emitting diodes, photocatalysts, hydrogen storage and hydrophobic surfaces.

Drawings

FIG. 1 is a low magnification SEM image of a mold internally grown SiC nanosphere of experiment one;

FIG. 2 is a high magnification SEM image of a mold internally grown SiC nanosphere of experiment one;

FIG. 3 is an SEM image of SiC nanowires grown on a growth substrate in experiment one;

fig. 4 is an XRD spectrum of the SiC nanowire obtained in experiment one;

FIG. 5 is a high magnification SEM image of the SiC nanospheres obtained in experiment two;

fig. 6 is an XRD spectrum of the SiC nanowire obtained in experiment two.

Detailed Description

The technical solution of the present invention is not limited to the following specific embodiments, but includes any combination of the specific embodiments.