A method for preparing SiC nano-spring
By using carbonized sugar and pre-oxidized Si powder, combined with controlled atmosphere sintering furnace, a catalyst-free preparation of SiC nanosprings was achieved. This solved the problem of the need for catalysts in the preparation of SiC nanosprings, and enabled the control of diameter, helix angle, and helix length, reducing costs and expanding application prospects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-01
- Publication Date
- 2026-04-07
AI Technical Summary
The preparation of SiC nanosprings in the present technology requires a catalyst and lacks methods to control the diameter, helix angle and helix length.
By using carbonized sugar as the carbon source and pre-oxidized Si powder as the silicon source, and by controlling the vacuum level and gas environment of the atmosphere sintering furnace, the carbon source is directly placed on the upper surface of the silicon source, and the concentrations of SiO and CO gases are adjusted, the growth of SiC nanosprings is achieved, avoiding the use of catalysts.
The preparation of SiC nanosprings under catalyst-free conditions has been achieved, and their diameter, helix angle and helix length can be controlled to reduce production costs and cycle time. Moreover, the product is helical in shape and is suitable for drug delivery, biosensors and energy storage.
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Figure CN117658143B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a preparation method of SiC nanospring. BACKGROUND
[0002] Nanospring is a kind of nanostructure with maximized surface. Nanospring has high surface area which makes it a carrier for loading catalyst. Nanospring can bear pressure of tens of times of its own weight. At the same time, its special helical structure and its own physical properties, such as piezoelectric property, energy storage property and mechanical property, have potential application prospect in the fields of drug transport, biosensor, energy storage and cell manipulation. Ding Xiangdong et al. think that tungsten metal nanospring has mechanical properties as bulk spring, its stored energy density is more than 1600 times of clockwork, and energy conversion efficiency is as high as 98% (Ding Xiangdong, Sun Jun. Energy storage: "nanospring" based on a new principle [J]. Chinese basic science, 2010, 12 (5): 3. DOI:10.3969 / j.issn.1009-2412.2010.05.004.). Kong et al. prepared ZnO nanospring by polar growth (Kong X Y, Ding Y, Yang R, et al. Single-Crystal Nanorings Formed by Epitaxial Self-Coiling of Polar Nanobelts [J]. Science, 2004, 303 (5662): 1348-1351. DOI:10.1126 / science.1092356.). D. N. McIIroy et al. prepared BC nanospring by vapor-liquid-solid growth mechanism, and thought that the axis of nanowire was offset due to larger catalyst particles, so as to form a helical structure (Mcilroy D N, Zhang D, Kranov Y, et al. Nanosprings [J]. Applied Physics Letters, 2001, 79 (10): 1540-1542. DOI:10.1063 / 1.1400079.). Wang et al. showed that ZnO nanospring has superelasticity (Gao P X, Mai W, Wang Z L. Superelasticity and Nanofracture Mechanics of ZnO Nanohelices [J]. Nano Letters, 2006, 6 (11): 2536. DOI:10.1021 / nl061943i.).
[0003] SiC has high strength, high hardness, wide band gap, strong oxidation resistance and high thermal conductivity. Limited by the preparation technology, there are few reports on SiC nanosprings, and catalysts are needed to prepare SiC nanosprings in the literature. So far, there is no report on the preparation of SiC nanosprings without catalysts, and there is no report on the preparation of SiC nanosprings with different diameters, helix angles and helix lengths. SUMMARY
[0004] The present application solves the problem of the need for catalysts in the preparation of existing SiC nanosprings, and proposes a preparation method of SiC nanosprings, which does not need catalysts in the preparation process and can realize the diameter, helix angle and helix length control of SiC nanosprings.
[0005] The preparation method of SiC nanosprings of the present application is carried out in the following steps:
[0006] I. Carbonization of sugar
[0007] The sugar is placed in a graphite crucible, a graphite cover is added and placed in an atmosphere sintering furnace for carbonization to obtain a blocky carbon source required for preparing SiC nanosprings;
[0008] The carbonization process is as follows: under the vacuum condition of 0.1-0.3 Pa, the atmosphere sintering furnace is heated to 400-600℃ at a heating rate of 5-20℃ / min, and after heating, it is kept for 0.5-2h, and then the furnace is cooled to room temperature;
[0009] II. Pre-oxidation of Si powder
[0010] The Si powder is placed in a beaker containing distilled water, the beaker is placed in a high temperature furnace, then it is kept at 120-150℃ for 0.5-24h to realize the oxidation of Si powder, and then the oxidized Si powder is dried to obtain a silicon source required for preparing SiC nanosprings;
[0011] III. Synthesis of SiC nanosprings
[0012] The silicon source obtained in step II is placed in a graphite crucible, and then the blocky carbon source obtained in step I is directly placed on the upper surface of the silicon source, the graphite crucible is covered with a graphite cover and placed in an atmosphere sintering furnace; vacuum is drawn to make the vacuum degree of the atmosphere sintering furnace at 0.1-0.3 Pa, then argon is filled into the atmosphere sintering furnace to standard atmospheric pressure, the atmosphere sintering furnace is heated to 1100-1350℃ at a heating rate of 10-30℃ / min and kept for 0.5-8h, then the power is turned off to naturally cool the furnace body to room temperature to obtain SiC nanosprings.
[0013] The present application has the following advantages:
[0014] 1. The SiC nanosprings of this invention utilize carbonized sugar as the carbon source and pre-oxidized Si powder as the silicon source. The amorphous SiO2 layer on the surface of the pre-oxidized Si powder facilitates the provision of SiO gas for SiC growth. The carbonized sugar, with its high activity, not only provides CO gas for SiC nanospring growth but also serves as a substrate for the growth of SiC nanosprings due to its bulk carbon source. Furthermore, the porous structure of the carbonized sugar helps restrict the straight growth of SiC, providing suitable space for the formation of helical structures. During the synthesis process, the high growth temperature and inert environment significantly limit the adsorption of foreign molecules (SiO and CO) on the SiC surface, resulting in uncompensated surface ionic charges. Consequently, the nanowires tend to fold to reduce electrostatic energy, thus forming a helical shape to lower electrostatic energy. This invention controls the vacuum level in the atmosphere sintering furnace to 0.1–0.3 Pa, and then fills it with inert gas. This effectively reduces the content of oxygen and other gaseous species in the growth chamber, greatly reducing the possibility of molecules adsorbing onto the SiC{111} surface and limiting the straight growth of SiC. This causes the product to tend to form a helical shape to reduce energy consumption. The invention places the carbon source directly on the surface of the silicon source instead of mixing them uniformly. This results in the CO and SiO gases required for SiC growth not forming synchronously and exhibiting different concentrations. The SiO gas concentration is lower further away from the silicon source, while the CO gas concentration is higher. Furthermore, the porous structure of the carbonized sugar causes these gas concentration differences. Therefore, gas molecules do not rapidly adsorb onto the nanowire ends, limiting the straight growth of SiC and causing it to tend to form a helical shape. Thus, placing the carbon source directly on the surface of the silicon source can provide a favorable atmosphere concentration for the growth of nanosprings.
[0015] 2. The preparation process of this invention does not use a metal catalyst, and there is no need to remove the metal catalyst by acid washing of the product, thereby greatly reducing the production cost and cycle.
[0016] 3. This invention adjusts the concentration of SiO and CO gases by changing the ratio of carbon source and silicon source and the reaction temperature, thereby adjusting the diameter, helix angle and helix length of the obtained SiC nanospring.
[0017] 4. The production process of this invention is simple, the preparation time is short, the requirements for raw materials, equipment and processes are relaxed, the operation is simple and the cost is low; the SiC nanosprings obtained by this invention have potential application prospects in the fields of drug delivery, biosensors, energy storage and cell manipulation. Attached Figure Description
[0018] Figure 1 The image shows a scan of the SiC nanospring obtained in Example 1.
[0019] Figure 2 This is a scan image of the SiC nanospring obtained in Example 2. Detailed Implementation
[0020] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination of the specific embodiments.
[0021] Specific Implementation Method 1: The preparation method of SiC nanosprings in this implementation method is carried out according to the following steps:
[0022] I. Carbonization of Sugar
[0023] Sugar was placed in a graphite crucible, covered with a graphite lid, and placed in an atmosphere sintering furnace for carbonization to obtain the bulk carbon source required for preparing SiC nanosprings.
[0024] The carbonization process is as follows: under vacuum conditions of 0.1 to 0.3 Pa, the atmosphere sintering furnace is heated to 400 to 600°C at a heating rate of 5 to 20°C / min, held at the temperature for 0.5 to 2 hours, and then cooled to room temperature with the furnace.
[0025] II. Pre-oxidation of Si powder
[0026] Si powder is placed in a beaker containing distilled water and placed in a high-temperature furnace. The beaker is then kept at 120–150°C for 0.5–24 hours to oxidize the Si powder. The oxidized Si powder is then dried to obtain the silicon source required for preparing SiC nanosprings.
[0027] III. Synthesis of SiC Nanosprings
[0028] The silicon source obtained in step two is placed in a graphite crucible, and then the block carbon source obtained in step one is placed directly on the upper surface of the silicon source. The graphite crucible is covered with a graphite cap and placed in an atmosphere sintering furnace. The atmosphere sintering furnace is evacuated to a vacuum degree of 0.1 to 0.3 Pa. Then, argon gas is introduced into the atmosphere sintering furnace to standard atmospheric pressure. The atmosphere sintering furnace is heated to 1100 to 1350 °C at a heating rate of 10 to 30 °C / min and held at that temperature for 0.5 to 8 hours. Then, the power is turned off and the furnace body is allowed to cool naturally to room temperature to obtain SiC nanosprings.
[0029] 1. In this embodiment, the SiC nanosprings were prepared using carbonized sugar as the carbon source and pre-oxidized Si powder as the silicon source. The amorphous SiO2 layer on the surface of the pre-oxidized Si powder facilitates the provision of SiO gas for SiC growth. The carbonized sugar is highly reactive, not only providing CO gas for the growth of SiC nanosprings, but also providing a substrate for the growth of SiC nanosprings from its bulk carbon source. The porous structure of the carbonized sugar helps to restrict the straight growth of SiC, providing suitable space for the formation of helical structures. During the synthesis process, the high growth temperature and inert environment greatly limit the adsorption of foreign molecules (SiO and CO) on the SiC surface, resulting in uncompensated ionic charges on the surface. The nanowires tend to fold to reduce electrostatic energy, thus forming a helical shape to reduce electrostatic energy. In this embodiment, the vacuum level in the atmosphere sintering furnace is controlled at 0.1–0.3 Pa, and then an inert gas is introduced. This effectively reduces the content of oxygen and other gaseous species in the growth chamber, greatly reducing the possibility of molecules adsorbing onto the SiC{111} surface and limiting the straight growth of SiC. This causes the product to tend to form a helical shape to reduce energy consumption. In this embodiment, the carbon source is placed directly on the surface of the silicon source instead of being uniformly mixed. This results in the CO and SiO gases required for SiC growth not forming synchronously and exhibiting different concentrations. The SiO gas concentration is lower further away from the silicon source, while the CO gas concentration is higher. Furthermore, the porous structure of the carbonized sugar leads to these gas concentration differences. Therefore, gas molecules do not rapidly adsorb onto the nanowire ends, limiting the straight growth of SiC and causing it to tend to form a helical shape. Thus, placing the carbon source directly on the surface of the silicon source can provide a favorable atmosphere concentration for the growth of nanosprings.
[0030] 2. The preparation process in this embodiment does not use a metal catalyst, and there is no need to remove the metal catalyst by acid washing of the product, thereby greatly reducing the production cost and cycle.
[0031] 3. In this embodiment, the concentrations of SiO and CO gases are adjusted by changing the ratio of carbon source and silicon source and the reaction temperature, thereby adjusting the diameter, helix angle and helix length of the obtained SiC nanospring.
[0032] 4. The production process of this embodiment is simple, the preparation time is short, the requirements for raw materials, equipment and process are relaxed, the operation is simple and the cost is low; the SiC nanosprings obtained by this embodiment have potential application prospects in the fields of drug delivery, biosensors, energy storage and cell manipulation.
[0033] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the sugar mentioned in step one is one or a mixture of glucose and sucrose.
[0034] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the carbonization process described in step 2 is as follows: Under a vacuum of 0.1 Pa, the atmosphere sintering furnace is heated to 600°C at a heating rate of 20°C / min, held at the temperature for 0.5 hours, and then cooled to room temperature with the furnace.
[0035] Specific Implementation Method Four: This implementation method differs from one of the specific implementation methods one to three in that: the carbonization process described in step two is as follows: under a vacuum of 0.2 Pa, the atmosphere sintering furnace is heated to 500°C at a heating rate of 10°C / min, held at the temperature for 1 hour, and then cooled to room temperature with the furnace.
[0036] Specific Implementation Method 5: This implementation method differs from Specific Implementation Methods 1 to 4 in that the Si powder mentioned in step 2 is industrial Si powder with an average diameter of 1 to 3 μm.
[0037] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the mass ratio of distilled water to Si powder in step two is 20 to 100:1.
[0038] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: in step three, a vacuum is drawn to make the vacuum degree of the atmosphere sintering furnace 0.2 Pa, and then argon gas is introduced into the atmosphere sintering furnace to the standard atmospheric pressure. The atmosphere sintering furnace is heated to 1250°C at a heating rate of 30°C / min and held at that temperature for 0.5 to 8 hours. Then the power is turned off and the furnace body is allowed to cool naturally to room temperature to obtain SiC nanosprings.
[0039] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: in step three, a vacuum is drawn to make the vacuum degree of the atmosphere sintering furnace between 0.1 and 0.3 Pa. Then, argon gas is introduced into the atmosphere sintering furnace to the standard atmospheric pressure. The atmosphere sintering furnace is heated to 1350°C at a heating rate of 20°C / min and held at that temperature for 4 hours. Then, the power is turned off and the furnace body is allowed to cool naturally to room temperature to obtain SiC nanosprings.
[0040] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the mass ratio of the carbon source and silicon source in step three is 1 to 2:1.
[0041] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that the mass ratio of the carbon source and silicon source in step 3 is 1:1.
[0042] Example 1:
[0043] The SiC nanospring in this embodiment is prepared according to the following steps:
[0044] I. Carbonization of Sugar
[0045] Sugar was placed in a graphite crucible, covered with a graphite lid, and placed in an atmosphere sintering furnace for carbonization to obtain the bulk carbon source required for preparing SiC nanosprings.
[0046] The sugar is glucose;
[0047] The carbonization process is as follows: under a vacuum of 0.1 Pa, the atmosphere sintering furnace is heated to 600°C at a heating rate of 20°C / min, held at the temperature for 0.5 h, and then cooled to room temperature with the furnace.
[0048] II. Pre-oxidation of Si powder
[0049] Si powder was placed in a beaker containing distilled water and placed in a high-temperature furnace. The beaker was then kept at 150°C for 12 hours to oxidize the Si powder. The oxidized Si powder was then dried to obtain the silicon source required for preparing SiC nanosprings.
[0050] The Si powder is industrial Si powder with an average diameter of 3 μm;
[0051] The mass ratio of distilled water to Si powder is 60:1;
[0052] III. Synthesis of SiC Nanosprings
[0053] The silicon source obtained in step two is placed in a graphite crucible, and then the block carbon source obtained in step one is placed directly on the surface of the silicon source. A graphite cap is added to the graphite crucible, and it is placed in an atmosphere sintering furnace. The atmosphere sintering furnace is evacuated to a vacuum level of 0.2 Pa, and then argon gas is introduced into the furnace to standard atmospheric pressure. The furnace is heated to 1250°C at a heating rate of 30°C / min and held at that temperature for 0.5–8 hours. The power is then turned off, allowing the furnace to cool naturally to room temperature, resulting in a SiC nanospring. The mass ratio of the carbon source to the silicon source is 2:1. The SiC nanospring obtained in this embodiment is as follows: Figure 1 As shown, the nanosprings exhibit a nanospring shape, and the absence of droplets at the nanowire ends indicates that the growth follows a gas-solid growth mechanism rather than a gas-liquid-solid growth mechanism. Therefore, acid washing to remove the metal catalyst is unnecessary, reducing production costs. The SiC nanospring pillars have a diameter of less than 100 nm and a spiral length of approximately tens of nanometers.
[0054] Example 2:
[0055] The SiC nanospring in this embodiment is prepared according to the following steps:
[0056] I. Carbonization of Sugar
[0057] Sugar was placed in a graphite crucible, covered with a graphite lid, and placed in an atmosphere sintering furnace for carbonization to obtain the bulk carbon source required for preparing SiC nanosprings.
[0058] The sugar is sucrose;
[0059] The carbonization process is as follows: under a vacuum of 0.2 Pa, the atmosphere sintering furnace is heated to 500°C at a heating rate of 10°C / min, held at the temperature for 1 hour, and then cooled to room temperature with the furnace.
[0060] II. Pre-oxidation of Si powder
[0061] Si powder was placed in a beaker containing distilled water and placed in a high-temperature furnace. The beaker was then kept at 130°C for 20 hours to oxidize the Si powder. The oxidized Si powder was then dried to obtain the silicon source required for preparing SiC nanosprings.
[0062] The Si powder is industrial Si powder with an average diameter of 1 μm;
[0063] The mass ratio of distilled water to Si powder is 60:1;
[0064] III. Synthesis of SiC Nanosprings
[0065] The silicon source obtained in step two is placed in a graphite crucible, and then the block carbon source obtained in step one is placed directly on the surface of the silicon source. A graphite cap is added to the graphite crucible, and it is placed in an atmosphere sintering furnace. The atmosphere sintering furnace is evacuated to a vacuum level of 0.1–0.3 Pa. Argon gas is then introduced into the atmosphere sintering furnace to standard atmospheric pressure. The furnace is heated to 1350°C at a heating rate of 20°C / min and held at that temperature for 4 hours. The power is then turned off, allowing the furnace to cool naturally to room temperature, resulting in a SiC nanospring. The mass ratio of the carbon source to the silicon source is 1:1. The SiC nanospring obtained in this embodiment is as follows: Figure 2 As shown, it exhibits a nanospring shape, with the SiC nanospring column having a diameter of approximately 400 nm and a spiral length of approximately 200–400 nm.
Claims
1. A method for preparing SiC nanosprings, characterized in that: The preparation method of SiC nanosprings is carried out according to the following steps: I. Carbonization of Sugar Sugar was placed in a graphite crucible, covered with a graphite lid, and placed in an atmosphere sintering furnace for carbonization to obtain the bulk carbon source required for preparing SiC nanosprings. The carbonization process is as follows: under vacuum conditions of 0.1~0.3Pa, the atmosphere sintering furnace is heated to 400~600℃ at a heating rate of 5~20℃ / min, held at the temperature for 0.5~2h, and then cooled to room temperature with the furnace. II. Pre-oxidation of Si powder Si powder is placed in a beaker containing distilled water and placed in a high-temperature furnace. The beaker is then kept at 120-150°C for 0.5-24 hours to oxidize the Si powder. The oxidized Si powder is then dried to obtain the silicon source required for preparing SiC nanosprings. III. Synthesis of SiC Nanosprings The silicon source obtained in step two is placed in a graphite crucible, and the block carbon source obtained in step one is placed directly on the surface of the silicon source. The graphite crucible is covered with a graphite cap and placed in an atmosphere sintering furnace. The atmosphere sintering furnace is evacuated to a vacuum degree of 0.1~0.3 Pa. Then, argon gas is introduced into the atmosphere sintering furnace to standard atmospheric pressure. The atmosphere sintering furnace is heated to 1100~1350℃ at a heating rate of 10~30℃ / min and held at that temperature for 0.5~8h. Then, the power is turned off and the furnace body is allowed to cool naturally to room temperature to obtain SiC nanosprings. The mass ratio of the carbon source to the silicon source is 1~2:
1.
2. The method for preparing SiC nanosprings according to claim 1, characterized in that: The sugar mentioned in step one is one or a mixture of glucose and sucrose.
3. The method for preparing SiC nanosprings according to claim 1, characterized in that: The carbonization process described in step two is as follows: Under vacuum conditions of 0.1 Pa, the atmosphere sintering furnace is heated to 600°C at a heating rate of 20°C / min, held at the temperature for 0.5 h, and then cooled to room temperature with the furnace.
4. The method for preparing SiC nanosprings according to claim 1, characterized in that: The carbonization process described in step two is as follows: Under vacuum conditions of 0.2 Pa, the atmosphere sintering furnace is heated to 500°C at a heating rate of 10°C / min, held at the temperature for 1 hour, and then cooled to room temperature with the furnace.
5. The method for preparing SiC nanosprings according to claim 1, characterized in that: The Si powder mentioned in step two is industrial Si powder with an average diameter of 1~3μm.
6. The method for preparing SiC nanosprings according to claim 1, characterized in that: The mass ratio of distilled water to Si powder in step two is 20~100:
1.
7. The method for preparing SiC nanosprings according to claim 1, characterized in that: Step 3: Vacuum the atmosphere sintering furnace to a vacuum level of 0.2 Pa, then fill the atmosphere sintering furnace with argon gas to standard atmospheric pressure, heat the atmosphere sintering furnace to 1250℃ at a heating rate of 30℃ / min and hold for 0.5~8h, then turn off the power and allow the furnace to cool naturally to room temperature to obtain SiC nanosprings.
8. The method for preparing SiC nanosprings according to claim 1, characterized in that: Step 3: Vacuum the atmosphere sintering furnace to a vacuum level of 0.1~0.3 Pa, then fill the atmosphere sintering furnace with argon gas to standard atmospheric pressure, heat the atmosphere sintering furnace to 1350℃ at a heating rate of 20℃ / min and hold for 4 hours, then turn off the power and allow the furnace to cool naturally to room temperature to obtain SiC nanosprings.
9. The method for preparing SiC nanosprings according to claim 1, characterized in that: The mass ratio of the carbon source to the silicon source in step three is 1:1.