Surface modification method for silicon carbide ceramic

Abstract

The invention discloses a surface modification method for silicon carbide ceramic. According to the method, the ceramic is subjected to surface modification by reaction of compound high-temperature molten sulfate and the silicon carbide ceramic, and mullite fibers are grown on the surface of the silicon carbide ceramic by the chemical reaction of the silicon carbide ceramic and the sulfate. Underthe condition that the strength of a silicon carbide body material is not reduced, the feature and the chemical properties of the silicon carbide body material are changed obviously. The silicon carbide / mullite compound material which is prepared by the method has high application value in the fields of ceramic industry, chemical industry, metallurgical industry and the like.

Description

technical field [0001] The invention relates to a modification method of inorganic materials, in particular to a new method for surface modification of silicon carbide ceramics. Background technique [0002] Silicon carbide ceramics are compounds with high hardness, high strength and high thermal conductivity formed by strong Si-C covalent bonds, but both Si and C belong to the main group IV elements, which are weak in attracting electrons and difficult to form ionic bonds. The Si-C covalent bond energy is large, the structure is stable, and the air atmosphere is heated to 1000 ℃ for a long time and it is not easy to be oxidized. Due to the stability of the chemical structure, it is extremely difficult to be modified, and its surface cannot be connected to other chemical groups through chemical reactions. Therefore, a stable bonding interface cannot be formed between silicon carbide ceramics, metals, and polymers. Therefore, there is an urgent need to study new methods for ...

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Problems solved by technology

Among them, chemical vapor deposition requires the use of dangerous silane gas, and the reaction temperature needs to be above 1200°C; physical vapor deposition requires complex and expensive equipment, and the deposited material needs to be sublimated and vaporized at high temperature before it can be deposited on the surface of the substrate. High energy consumption; inorganic coating modification is simple physical coating on the surface of the substrate with other inorganic materials, so the surface is not tightly bonded, and the coating material is easy to fall off; graft modification with organosilane coupling agent is to initiate coupling The chemical agent reacts with the surface of silicon carbide to form a chemical bond to connect the organic group to the surface of the silicon carbide ceramic substrate, so the surface modification layer formed is a monomolecular layer, which cannot be used in high temperature, high corrosion and other environments; ion beam assisted deposition The method is to use plasma to modify the surface of the substrate. This method requires more complicated equipment, and the thickness of the modified layer is limited.

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