Preparation process of ZrC-ZrB2-SiC ceramic composite powder by precursor conversion method

Abstract

The invention discloses a preparation process of ZrC-ZrB2-SiC ceramic composite powder by a precursor conversion method. Zirconium oxychloride octahydrate, boric acid, ethyl orthosilicate and glucoseare used as starting raw materials, and absolute ethyl alcohol and deionized water are used as solvents, wherein the molar ratio of the boric acid to the zirconium oxychloride octahydrate to the ethylorthosilicate is (1-5):1:(0.5-5), and the mass ratio of the glucose to the ethyl orthosilicate is (1-4):1. A zirconium precursor solution, a boric acid solution, an ethyl orthosilicate solution and aglucose solution are prepared separately, the solutions are uniformly mixed to obtain a boron-silicon-zirconium precursor solution, the boron-silicon-zirconium precursor solution is dried, and heat treatment is carried out at 1450-1600 DEG C for 1-2 hours under the protection of an argon atmosphere to obtain the ZrC-ZrB2-SiC ceramic powder. The prepared ceramic powder is uniform in particle sizeand the average particle size is about 150 nm. The preparation process has the characteristics of simple process, short period, low energy consumption and low cost, and the obtained ceramic phase is uniform and fine in particle size and high in purity.

Description

technical field [0001] The invention belongs to the technical field of inorganic non-metallic materials, and relates to the preparation of ultra-high temperature ceramic raw material powder, in particular to a ZrC-ZrB 2 -Precursor conversion method preparation process of SiC ceramic composite powder. Background technique [0002] ZrB has been 2 Ceramics have always been a hot topic of research by scientists because of their excellent properties. They have the characteristics of low density, high melting point, high specific modulus, anti-ablation, good physical stability and thermochemical stability, and are extremely potential for ultra-high temperature ceramic materials. a material. Since single-phase ZrB 2 Poor oxidation resistance, inherent brittleness and limited sinterability under thermal shock conditions affect its application in ultra-high temperature fields. Now more and more researchers focus on ZrB 2 Research on matrix composite ceramic powder. Studies have...

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Problems solved by technology

[0003] Currently preparing ZrC-ZrB 2 -The commonly used methods for SiC ceramic powder are: (1) mechanical ball method, that is, Zr powder, Si powder, B 4 C and the carbon source are uniformly mixed by ball milling, but the raw material powder is easily oxidized during the ball milling process, the raw material itself contains oxygen impurities, the reaction temperature is too low, and the in-situ reaction is not sufficient, resulting in the easy introduction of oxide phases into the product

(2) The molten salt method can greatly reduce the synthesis temperature, but the temperature of the molten salt and the amount of reducing agent added have a great influence on the ZrC-ZrB 2 -The synthesis of SiC ceramic powder has a great influence, and the ZrC-ZrB in the synthesized composite powder 2 -SiC content is low, it is difficult to prepare pure ZrC-ZrB 2 -SiC ceramic powder

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