Graphite material with SiC coating and preparation method thereof

Abstract

The invention discloses a graphite material with a SiC coating and a preparation method thereof. The graphite material comprises a graphite base and a SiC coating. The SiC coating comprises a primary SiC layer and a secondary SiC layer. The primary SiC layer permeates into the graphite base from the surface of the graphite base and is formed by an in-situ reaction of gaseous silicon and the graphite base. The secondary SiC layer is located on the primary SiC layer. The preparation method comprises 1, carrying out vapor silicon infiltration sintering on a graphite material to obtain a graphite material with the primary SiC layer and 2, carrying out vapor deposition of the secondary SiC layer. The graphite material with the SiC coating has the advantages that the SiC coating has good cohesiveness to the graphite material, has no thermal expansion coefficient mismatch, is compact and has high oxidation resistance. The preparation method effectively solves the problem of thermal expansion coefficient mismatch in preparation of the SiC coating on the surface of the graphite material directly through a CVD technology, and guarantees high bonding strength between the coating and graphite.

Description

technical field [0001] The invention belongs to the field of graphite materials, in particular to a graphite material with SiC coating 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, since graphite materials will oxidize and corrode in high temperature and oxidizing environments, which will cause gradual damage to components, so graphite materials are usually coated when they are used in some specific corrosive fields. For example, when growing single-crystal GAN ​​materials epitaxially, graphite trays are needed. Because graphite materials will corrode and drop powder under high-temperature and corrosive gas environments, powder impurities will be introduced into single-crystal materials to solve the problem of graphite trays. An effective technical approach to the corrosion problem is to apply an overall dense prote...

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Problems solved by technology

Traditional preparation methods usually use chemical vapor deposition (CVD) or brushing to directly deposit a layer of SiC coating on the graphite surface, but SiC coatings and graphite materials have some differences in physical and chemical properties such as inconsistent expansion coefficients, so The bonding strength between the coating and the graphite material is not high, and it is easy to fall off; some use a two-step deposition method, first deposit a layer of solid Si, use the Si and graphite surface to react the primary layer of SiC, and then deposit the secondary SiC coating layer, but the reaction activity between solid Si and graphite in this method is limited, and the reaction is only limited to the surface of graphite, and SiC particles cannot fully penetrate into the interior of graphite, resulting in a low bonding strength between SiC coating and graphite material.

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