Graphite material with sic doped layer and preparation method thereof

Abstract

The invention discloses a graphite material with a SiC doped layer and a preparation method of the graphite material. The preparation method of the graphite material with the SiC doped layer comprises the following step: by taking mixed powder of silicon-containing powder and boron nitride as a silicon source, performing liquid-phase siliconing sintering on a graphite material, thereby obtaining the graphite material with the SiC doped layer. The graphite material with the SiC doped layer prepared by using the method comprises a graphite substrate and the SiC doped layer on the surface of the graphite substrate, the SiC doped layer is well combined with the graphite substrate without thermal mismatch, the graphite material is good in oxidation and corrosion resistance and relatively low in cost, and a small amount of silicon is adhered to the surface of the graphite material.

Description

technical field [0001] The invention belongs to the field of graphite materials, in particular to a graphite material with a SiC doped layer and a preparation method thereof. Background technique [0002] Graphite materials have the advantage of high temperature resistance, and are widely used in many high temperature structural fields. However, due to the oxidation and corrosion of graphite materials in high temperature and oxidizing environments, the components are gradually damaged. Therefore, improving the high-temperature oxidation resistance of graphite materials is of great significance for expanding the scope of use of graphite products and giving full play to the potential of graphite materials. [0003] High-purity silicon carbide (SiC) material has a series of excellent properties such as low density, high temperature resistance, oxidation resistance, erosion resistance, and corrosion resistance. It is an ideal material for improving the oxidation resistance of g...

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Problems solved by technology

But at the same time, the silicon carbide layer coated on the surface of the graphite substrate hinders the reaction between the molten silicon and the graphite substrate, and the unreacted molten silicon tends to nucleate and grow silicon grains on the surface of the silicon carbide coating when the temperature drops below the melting point. A large amount of unreacted solid silicon remains on the surface of SiC. These residual silicon are closely combined with the SiC layer, which increases the processing difficulty after siliconizing, and the corrosion resistance of silicon is worse than that of silicon carbide. The presence of residual silicon will weaken siliconizing. Corrosion resistance of post graphite materials

In vapor phase siliconizing technology, gas phase silicon enters the interior of the graphite matrix and reacts with carbon in situ to form silicon carbide, but the resulting silicon carbide layer has a higher opening porosity, lower density, and there is also the problem of more residual silicon on the surface

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