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Preparation method of nano silicon carbide

wallpapers Industry 2020-10-23
1 Shape memory synthesis method

Its main meaning is that the macrostructure of the starting solid reactant can be maintained to a certain extent before and after the synthesis reaction. In 1988, French Ledoux and his colleagues first proposed and used this method to prepare high-specific surface area silicon carbide and SiC materials with different structures. After that, people continued to use this method to prepare silicon carbide nanowires, nanotubes, nanospheres and high specific surface silicon carbide.

2 Sol-gel and carbothermic reduction method

The sol-gel method uses compounds containing high chemically active components as precursors, mixes these raw materials uniformly in the liquid phase, and conducts hydrolysis and condensation chemical reactions to form a stable transparent sol system in the solution. The colloidal particles slowly polymerize to form a gel with a three-dimensional network structure. The gel network is filled with solvents that lose fluidity to form a gel. The gel is dried, sintered and solidified to prepare molecular and even nanostructured materials. Because of its low cost, simple process, and relatively low reaction temperature, it has become a common method for preparing silicon carbide. The sol-gel method used to be used to prepare silicon carbide powder, silicon carbide fibers and silicon carbide whiskers. Now it is also used to prepare some advanced silicon carbide materials such as nanowires, nanorods, nanoparticles or nanowhiskers.

Since the sol-gel process can obtain uniform SiC, it has attracted attention. In the reaction process, carbon black, activated carbon, carbon fiber, phenolic resin, starch, sucrose, etc. are generally used as the carbon source, and the sol of silicic acid is used as the silicon source. Some people also use high polymers of organic silicon (that is, there are both carbon and silicon sources in the same molecule) to obtain silicon carbide through pyrolysis.
3 Carbon nanotubes limit the reaction

Carbon nanotube restricted reaction is a method of synthesizing one-dimensional nanomaterials through the reaction of carbon nanotubes with volatile metal oxides and chlorides. The prerequisite for choosing this method is that carbon nanotubes are resistant to high temperatures and the vapor pressure of carbon atoms is low. When a substance with a higher vapor pressure is added to the system, it may cause its molecules to migrate around the carbon nanotubes and attach to it. The surface or spread to its interior. Since the reaction is restricted to carbon nanotubes, the resulting silicon carbide can only have a one-dimensional morphology.

4 Chemical vapor deposition method

Chemical vapor deposition generally refers to a method in which reactants undergo chemical reactions and condensation processes to produce specific products. Chemical vapor deposition can be the thermal decomposition of a single compound, which must have all the elements required for the product. In addition, a gas phase reaction between two or more substances can also be used. This method can be combined in many ways. The advantage is that silicon carbide with high purity can be prepared.

5 Arc discharge method

The arc discharge method is one of the most important methods for preparing nanometer silicon carbide. The principle is to use arc discharge to make the reaction temperature up to 2000°C or more, accelerate the synthesis of reactants, and promote the volatilization of catalysts and other impurities at high temperatures to obtain high-purity nano silicon carbide particles and silicon carbide nanowires.

6 Other methods

Chemical corrosion method: Chemical corrosion is a method in which micron-sized SiC powder is placed in an etching solution and corroded by light or heating to obtain samples.

Electrochemical corrosion method: Place the sample to be corroded on the anode, such as Si, SiC multi-chips, etc., add molybdenum, platinum and other metal electrodes on the cathode, and then add electric current, supplemented by light, etc., to corrode the anode sample to obtain porous nano material.

Magnetron sputtering method: Sputtering carbon ions and silicon ions onto a silicon dioxide substrate, and then annealing at a high temperature to obtain SiC nanoparticles.
 
Trunnano is one of the world's largest producers of nano silicon carbide powder. If you have any questions or needs, please contact Dr. Leo by email: brad@ihpa.net.

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