Method for preparing graphene toughened silicon carbide ceramic composite material

Abstract

The invention belongs to the field of macromolecule inorganic chemistry, and in particular relates to a method for preparing a graphene toughened silicon carbide ceramic composite material. Specifically, the method comprises the following steps: by taking graphite oxide as a carbon source, wrapping the surface of reduced graphene oxide with a layer of SiO2 granules by using a hydrothermal method so as to form a good interface layer between graphene and SiC, uniformly dispersing, and implementing carbon thermal reduction reaction at the interface of graphene and SiO2 in the high-temperature sintering process so as to growth silicon carbide crystal whisker and granules in situ, thereby improving the interface strength and the oxidation resistance, achieving an interface intensification function, improving crack expansion resistance and further improving the fracture toughness of ceramic. The method aims at the defects that graphene is poor in dispersity and high-temperature oxidation resistance in a conventional graphene / silicon carbide composite material, in-situ growth, crack self-healing and toughness mechanisms are applied to a preparation technique of a graphene / silicon carbide material, and thus graphene toughened silicon carbide ceramic with excellent mechanical properties and interface binding properties can be prepared.

Description

technical field [0001] The invention belongs to the field of macromolecular inorganic chemistry, and in particular relates to a preparation method of a graphene-toughened silicon carbide ceramic composite material. Background technique [0002] Silicon carbide ceramics have the characteristics of high temperature resistance, high hardness, wear resistance, low thermal expansion coefficient, high thermal conductivity, chemical corrosion resistance, dielectric, and wave penetration. Broad application prospects. However, since silicon carbide is a stable compound with strong covalent bonds, it has low thermal diffusivity and is difficult to sinter and densify. At the same time, silicon carbide ceramics have defects such as high brittleness, poor high temperature oxidation resistance, easy cracks, and short service life. , limiting its application under high temperature conditions. Therefore, it is urgent to develop a new silicon carbide ceramic material with high density, hig...

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Problems solved by technology

However, the disadvantage of these methods is that graphene is very easy to agglomerate and has poor dispersion. If it is directly mixed with silicon carbide mechanically, the uniformity of the material will be poor. At the same time, the interface bonding strength between graphene and silicon carbide is not high. The anti-oxidation performance under the above oxygen atmosphere is greatly reduced, and cracks and pores are prone to occur, so that the oxidizing medium can directly act on the inside of the material at high temperature, weakening the anti-oxidation ability, shortening the life, and seriously affecting the high-temperature mechanical properties of the composite material.

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