Preparation method of silicon carbide nanometer crystal whiskers

Abstract

The invention discloses a preparation method of silicon carbide nanometer crystal whiskers. According to the technical scheme, 10 wt%-40 wt% of organosilicone and 60 wt%-90 wt% of pitch organic solvent soluble components or resin organic solvent soluble components, co-cracking is conducted on an obtained solution for 2-6 h on the condition that the temperature ranges from 250 DEG C to 450 DEG C, and silicon-doped pitch or silicon-doped resin is obtained; carbonization is conducted on the silicon-doped pitch or the silicon-doped resin for 1-3 h on the conduction that the temperature ranges from 700 DEG C to 900 DEG C, and silicon-doped pitch-based carbon materials or silicon-doped resin-based carbon materials are obtained. The silicon-doped pitch-based carbon materials or the silicon-doped resin-based carbon materials are ground into fine powder and filled into a mold, mechanical pressing is conducted, and demoulding is conducted; a graphite crucible filled with a green body is put into a high-temperature carbonization furnace, heat treatment is conducted for 1-3 h at the temperature ranging from 1200 DEG C to 1800 DEG C in an inert atmosphere, natural cooling is conducted, and the silicon carbide nanometer crystal whiskers are obtained. According to the preparation method of the silicon carbide nanometer crystal whiskers, a catalyst does not need to participate, and the prepared silicon carbide nanometer crystal whiskers have the advantages of being high in purity, large in length-diameter radio and easy to collect.

Description

technical field [0001] The invention belongs to the technical field of silicon carbide nanomaterials. In particular, it relates to a preparation method of silicon carbide nano-whiskers. Background technique [0002] Silicon carbide whiskers (SiC w ) is a high-purity single-crystal material with diameters ranging from nanometers to micrometers, with high melting point (>2700°C), low density, excellent tensile strength (tensile strength is 2100MPa), and good specific strength and specific elastic modulus It is widely used as a reinforcing and toughening additive for various high-performance materials, and is used in aerospace, national defense and civil industries (Ning Shufan. Preparation method and application of SiC whiskers. Journal of Xi'an Shiyou University, 2004 , 19(1)). [0003] At present, all SiC whisker preparation processes mainly include two types: gas phase reaction method and solid material method, (Hao Bin. Research progress on SiC whisker preparation me...

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Problems solved by technology

However, no matter which method is used to prepare silicon carbide whiskers, different types of catalysts are used, and the addition of these catalysts greatly affects the purity of silicon carbide whiskers, which limits its wider application.

Wen Guangwu et al. used silicon tetrachloride (SiC1 4 ), benzaldehyde (PhCHO), alkylamine (RNH 2 ) and boron trichloride (BCI 3 ) as raw materials, a large number of β-SiC nano whiskers with good crystallinity were prepared on the surface of the material by the gas pressure synthesis method without using a catalyst (Wen Guangwu et al. Growth of β-SiC nanowires from SiBONC ceramic powder. Rare metal Materials and Engineering, 2008, 37 (3): 561-564), the diameter of the prepared silicon carbide nano whiskers is 20~200nm, and the average length is about 1mm, but the raw materials used in the gas pressure synthesis method have great toxicity and corrosion nature, and the reaction conditions are relatively harsh, and the preparation cost of β-SiC nano whiskers is relatively high

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