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Properties and preparation methods of silicon carbide nanofibers

wallpapers Industry 2020-10-23
SiC nanofibers are representative of non-oxide ceramic fibers. The basic properties and preparation methods of SiC nanofibers are described in detail.

Basic properties of SiC nanofibers

As a high-performance ceramic material, silicon carbide fiber is mainly composed of carbon and silicon. Silicon carbide is divided into two types from the morphology: continuous silicon carbide fiber and whisker. Silicon carbide fiber has excellent properties such as high fiber strength, chemical resistance, high temperature resistance and high modulus. Fiber-reinforced ceramic matrix composites, as an important new ceramic material, have received widespread attention in high-tech fields, such as aerospace, military weapons and equipment.
SiCf/SiC composite nanofiber is a kind of SiC reinforcing material, and its main applications are as follows: (1) As a thermal structure material and thermal protection material for aerospace aircraft. (2) As the thermal structural component of high temperature and high performance engine. (3) As the first wall material of nuclear reactors, it is mainly used in nuclear fusion devices. (4) Application in civil applications.

SiC nanofiber preparation method

There are many methods for preparing SiC nanofibers, the main methods are as follows:

(1) Chemical vapor deposition method. This method is the earliest method to realize SiC nanowires. The silicon carbide fiber prepared by the chemical vapor deposition method has the advantages of high purity, good stability and creep resistance at high temperature, but the silicon carbide nanofiber prepared by this method is not easy to prepare composite materials. Shinanlin and others of the Institute of Metal Research of the Chinese Academy of Sciences successfully obtained SiC nanofibers by chemical vapor deposition in 1990. The silicon carbide fiber prepared by this method has a protective layer on its surface that can alleviate the damage sensitivity of the fiber surface, and finally achieves the improvement of SiC nanofibers. The purpose of fiber properties.

(2) The precursor transformation method. In 1975, the team of Professor Yajima of Tohoku University in Japan first developed a pioneer conversion method to prepare fibers. The method mainly consists of the following four processes: precursor synthesis, melt spinning, stabilization and high temperature sintering. The first domestic university that began to develop silicon carbide fiber preparation was the National University of Defense Technology. The silicon carbide fiber successfully prepared by this school showed good mechanical properties.

(3) Activated carbon fiber conversion method. The silicon carbide fiber prepared by this method has high tensile strength, which can reach more than 1000MPa. The method can successfully prepare fibers through the following three steps. First, the organic fibrils are processed to obtain activated carbon fibers; secondly, the activated carbon fibers and gaseous silica are chemically reacted to successfully convert the activated carbon fibers into silicon carbide fibers; finally, the silicon carbide fibers After heat treatment, the final product-silicon carbide nanofiber is obtained.

(4) Electrospinning method. Li successfully prepared hollow nanofibers by electrospinning. The fibers prepared by this method have uniform size and good fiber morphology; Wang [98] et al. used TEOS as a silicon source and polyvinylpyrrolidone as a spinning aid to prepare a continuous 200nm diameter fiber. Silicon carbide fiber.
 
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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