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

Abstract

The invention discloses a method for preparing a monocrystalline silicon carbide nanofiber / silicon carbide ceramic matrix composite material by reaction sintering. The method comprises the following steps: preparing a SiC nanofiber coated with a carbon / BN coating from a monocrystalline silicon carbide nanofiber; impregnating or stirring and dispersing the SiC nanofiber in an ethanol / water suspension containing nanometer carbon black / silicon carbide particles; and preparing a SiCNf preform by vacuum suction filtration or rolling: placing the above interfacial layer deposited nanofiber preform in a molding die, further carrying out press molding, carrying out high-temperature dumping to obtain a high-density SiCNf preform, and then performing reaction infiltration. Compared with in-situ grown SiC nanowire / fiber (SiCnf) reinforced SiC ceramic matrix composite materials, the composite material of the invention has the advantages of easiness in preparation of the interfacial coating of the SiCNf and the matrix, high volume content of the SiCNf, and high density.

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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