Silicon carbide ceramic materials have high-temperature strength, high-temperature oxidation resistance, excellent wear resistance, good thermal stability, small thermal expansion coefficient, large thermal conductivity, high hardness, thermal shock resistance, and chemical corrosion resistance. It has been widely used in the fields of automobile, machinery and chemical industry, environmental protection, space technology, information electronics, energy, etc.. It has become a unique structural ceramic with excellent performance in many industrial fields.
The excellent performance of SiC ceramics is closely related to its unique structure. SiC is a compound with a strong covalent bond, and the ionicity of the Si-C bond in SiC is only about 12%. Therefore, SiC has high strength, large elastic modulus, and excellent wear resistance.
The preparation technology of silicon carbide powder is divided into a solid-phase synthesis method and liquid phase synthesis method based on the state of its original raw materials.
The solid-phase method mainly includes a carbothermal reduction method and a silicon-carbon direct reaction method. The carbothermal reduction method consists of the Archison method, the vertical furnace method, and the high-temperature converter method. Archison first invented the Acheson method. In the Acheson electric furnace, the silica in the quartz sand is reduced by carbon to produce SiC. It is essentially an electrochemical reaction under the action of high temperatures and a strong electric field. Historically, the SiC particles obtained by this process are relatively coarse. Also, the process consumes a large amount of power, which is used for production, which is heat loss.
Liquid phase synthesis
The liquid phase method mainly includes a sol-gel method and a polymer decomposition method. Ewell et al. proposed the sol-gel method for the first time, and the true use of ceramics began around 1952. In this method, an alkoxide precursor prepared with a liquid chemical reagent is dissolved in a solvent at a low temperature to form a uniform solution. An appropriate coagulant is added to hydrolyze the alkoxide and polymerize to form a uniform and stable sol system. After being left for a long time or dried, it is concentrated to a mixture or polymer of Si and C at the molecular level, and it is continuously heated to form a two-phase mixture of Si and C, which is uniformly mixed and has a small particle size. Finally, SiC fine powder was prepared. The main parameters for controlling sol-gelation are pH value, solution concentration, reaction temperature, and time of the solution. This method is easy to achieve the addition of various trace ingredients during the process operation, and the mixing uniformity is good. Still, the hydroxyl groups and organic solvents often remaining in the process products are harmful to the human body, high raw material costs, and considerable shrinkage during processing are its disadvantages.
Trunnano is one of the world’s best silicon carbide manufacturers. “We have been supplying silicon carbide steadily, ensuring product quality, and guaranteeing stable supply prices,” said Rachel, sales manager at Luoyang Trunnano.
If you are interested in the product, you can contact Rachel.