Molybdenum disilicide/silicon carbide three-dimensional polymer precursor ceramic and preparation method thereof

Abstract

The invention discloses molybdenum disilicide / silicon carbide three-dimensional polymer precursor ceramic and a preparation method thereof, belonging to preparation of ceramic materials. The preparation method comprises the following steps: putting precursor PVG powder into a graphite paper boat and carrying out high-temperature cracking under the protection of an inert atmosphere; mixing MoSi2, cracked SiC(rGO)p ceramic particles and the precursor PVG powder to form a MoSi2 / SiC(rGO)p / PVG mixture, carrying out ball milling and uniform mixing in an alcohol medium, and then drying the MoSi2 / SiC(rGO)p / PVG mixture in an oven; and loading the mixture into a mold for compression molding, conducing demolding to obtain a biscuit, putting the biscuit into an inert atmosphere tube furnace for high-temperature sintering, and conducting cooling along with the furnace to obtain black molybdenum disilicide / silicon carbide three-dimensional polymer precursor ceramic, namely 3D-SiC(rGO, MoSi2x) nanometer composite block ceramic for short, wherein x is the mass fraction of silicon carbide in the whole biscuit. The obtained ceramic is high in heat conductivity and electric conductivity and good in formability and component uniformity; and the preparation method is simple and economical in process.

Description

technical field [0001] The invention relates to the preparation of ceramic materials, in particular to a molybdenum disilicide / silicon carbide three-dimensional polymer precursor ceramic and a preparation method thereof. Background technique [0002] As an advanced ceramic material, silicon carbide (SiC) has excellent mechanical properties, high temperature resistance, thermal shock resistance, chemical stability, corrosion resistance, etc. It also shows good performance under environmental conditions. It is often used to make corrosion-resistant materials, wear-resistant materials, high-temperature-resistant components, high-precision components, etc., in the fields of microelectronic systems, machinery, chemical industry, metallurgy, aerospace, national defense and military industry, etc. All have essential applications. [0003] At present, SiC ceramics can be obtained by normal pressure sintering, hot pressing sintering, reaction sintering and other preparation methods....

AI Technical Summary

Problems solved by technology

Chinese patent ZL 201610850564.3 discloses a method for preparing silicon carbide ceramic materials with low residual silicon by a multi-step reaction sintering method, mixing different carbon sources into silicon carbide powder, adding phenolic resin or PVA mechanical mixing, and vacuum conditions at 1600-1700 °C High-density silicon carbide ceramics with better thermal conductivity and high-temperature mechanical properties can be obtained by lower sintering, and at the same time, the problem of poor mechanical properties caused by excessive residual silicon content in silicon carbide ceramics is solved

The polycarbosilane precursor escapes a large amount of small molecule gas during cracking, causing a large number of holes in the ceramic to affect the density, or shrinkage causes a large number of cracks in the ceramic, which eventually causes serious damage and cannot be molded, and the amorphous SiOxCy phase and free carbon phase The presence of silicon carbide ceramics makes the mechanical properties poor

Chinese patent ZL 201711494377.7 discloses a method for preparing graphene / silicon carbide monolithic ceramics by high-temperature pyrolysis of graphene oxide-vinyltriethoxysilane-polycarbosilane precursors, and preparing three-dimensional silicon carbide ceramics by the precursor method New breakthroughs have been made in the field, but the overall performance of the obtained monolithic ceramics is not good, which limits its application

Chinese patent CN 110467467 A discloses a method of blending and re-cracking, which makes graphene / silicon carbide monolithic ceramics have higher ceramic yield and lower linear shrinkage, but ceramics have functional properties such as high temperature resistance and fracture toughness. needs improvement

The above method will be directly mixed with SiC inorganic ceramic powder to obtain a composite ceramic material, and there will inevitably be interface separation, which will seriously affect the mechanical properties, especially the fracture toughness.

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