Method for preparing single crystal silicon carbide nanofiber/silicon carbide ceramic matrix composite material by reaction sintering

Abstract

The invention discloses a method for preparing single crystal silicon carbide nanofiber / silicon carbide ceramic matrix composite material by reaction sintering. First, single crystal silicon carbide nanofibers were used as raw materials to prepare SiC nanofibers coated with carbon / BN coating; then the ethanol / water suspension containing nano-carbon black / silicon carbide particles was impregnated or stirred with SiC nanofibers; Preparation of SiC by vacuum filtration or rolling nf Prefabricated body: Place the above-mentioned nanofiber prefabricated body with the deposited interface layer in the forming mold, further pressurize and form, and obtain high-density SiC through high-temperature debinding nf The prefabricated body is then subjected to reactive infiltration. In situ growth of SiC nanowires / fibers (SiC nf ) Compared with the reinforced SiC ceramic matrix composite, the SiC of the present invention nf The interface coating with the substrate is easy to prepare, SiC nf The volume content is large and the density is high.

Description

technical field [0001] The invention relates to a method for preparing a silicon carbide composite material, in particular to a method for preparing a single crystal silicon carbide nanofiber / silicon carbide ceramic matrix composite material by reaction sintering. Background technique [0002] The biggest disadvantage of ceramics is their high brittleness and poor thermal shock resistance, which limit their application in the field of thermal structural materials. Fiber / whisker reinforcements are usually introduced into ceramics to improve the toughness of ceramics. In particular, continuous SiC ceramic fiber reinforced and toughened SiC ceramic matrix composites (SiCf / SiC CMC) not only retains the advantages of SiC ceramics such as high temperature resistance, high strength, oxidation resistance, corrosion resistance, and impact resistance, but also SiCf / SiC ceramic matrix composites. It has low density, stable performance at high temperature, low tritium permeability and ...

AI Technical Summary

Problems solved by technology

[0004] The above SiC ceramic matrix composites reinforced by SiC nanowires / fibers (SiCnf) grown in situ have a small volume content of SiCnf, the interface between SiCnf and the matrix is ​​difficult to control, and the growth quality of SiCnf is affected by the size and distribution of pores or gaps. Composite materials often There is a "bridging" effect, which makes it difficult to fully reflect the excellent mechanical properties of SiC

Due to the lack of large-scale preparation of SiCnf in the early stage, there are few reports on high-volume, high-density single-crystal SiCnf-reinforced SiC ceramic composites (usually introduced into the material matrix as a second reinforcement, and the content is small)

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