Preparation method of silicon carbide ceramic precursor polycarbosilane

Abstract

The invention discloses a preparation method of silicon carbide ceramic precursor polycarbosilane. The method comprises the following steps: (1) adding sodium metal into a reaction solvent, heating upunder stirring and gradually adding halomethyltrialkoxysilane to continue the reaction so as to mainly produce sodium salt, alkoxy-containing polycarbosilane and sodium alkoxide; (2) removing the sodium salt produced in the step (1), adding a reducing agent after heating up, and reducing the alkoxy-containing polycarbosilane to produce a polycarbosilane product. Raw materials used in the preparation are simple in source and high in polymerization activity, and can introduce crosslinking groups through a plurality of different ways; and the obtained polycarbosilane has low viscosity and high purity, and can obtain silicon carbide ceramics with near-stoichiometric ratios after sintering.

Description

Technical field

[0001] The invention relates to the field of silicon carbide ceramics, in particular to a method for preparing polycarbosilane, a precursor of silicon carbide ceramics. Background technique

[0002] The precursor transformation method to prepare ceramics was founded by Verbeek in Germany and Yajima in Japan in the mid-1970s. The precursor conversion of high-performance ceramic materials can flexibly control and improve the chemical structure, phase composition, atomic distribution and microstructure of ceramic materials, especially in the preparation of SiC, Si 3 N 4 High-performance non-oxide ceramics such as Si-C-N and other high-performance non-oxide ceramics have advantages unmatched by traditional ceramic preparation processes, and have received widespread attention from academia and industry. The so-called precursor conversion method to prepare ceramics is to first prepare a polymer that can be converted into ceramic materials by high-temperature pyrolysis t...

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