Method for preparing SiC coating on surface of spherical graphite material

Abstract

The invention provides a method for preparing a SiC coating on the surface of a spherical graphite material. The method comprises the steps of (1) mixing Si powder, SiC powder, Al2O3 powder and graphite powder, so as to obtain embedding powder; (2) embedding the spherical graphite material into the embedding powder, and jolt-ramming an embedded mixture, so as to obtain the embedded mixture after jolt-ramming; (3) performing sintering treatment on the embedded mixture after jolt-ramming in an argon atmosphere, so as to obtain sintering treatment products; (4) performing chemical vapor deposition on the sintering treatment products in a spouted fluidized bed in the condition that methyl trichlorosilane, hydrogen and argon are introduced, so as to form the SiC coating on the surface of the spherical graphite material. By utilizing the method, the SiC coating which has the advantages of integrity in coating, uniformity in thickness, good transitivity and high bonding strength with a substrate can be rapidly and effectively prepared on the surface of the spherical graphite material.

Description

technical field [0001] The invention belongs to the technical field of nuclear application, and in particular relates to a method for preparing a SiC coating on the surface of a spherical graphite material. Background technique [0002] Graphite is one of the foundations on which nuclear reactors are built. It is not only the main component of reactor structural support materials and shielding materials, but also the matrix material of fuel elements in fourth-generation high-temperature air-cooled reactors. Therefore, the research on graphite materials is of great importance to the safety and security of reactors. Development is very important. Graphite materials have outstanding advantages such as high temperature resistance, small neutron absorption cross-section, stable chemical properties, and excellent high-temperature mechanical properties. The biggest disadvantage is that it is easy to react with oxidizing gases above 500°C and fail. [0003] Graphite materials are w...

AI Technical Summary

Problems solved by technology

This method is simple in process and low in cost, but the particle size in the coating slurry is large, which is not ideal for impregnating the micropores in the matrix material; at the same time, the coating prepared by this method has a high sintering temperature, poor density, and is easy to crack. The thickness of the coating is not uniform and the surface is rough

[0011] Therefore, the current SiC coating preparation process still needs to be improved.

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