Preparation and anti-oxidation performance of TaC-SiC nanocomposites by precursor-derived ceramic method

Abstract

As a kind of ultra-high temperature ceramic, TaC is widely used in aerospace field. In order to improve its high temperature oxidation resistance, SiC is usually added as a second phase. TaC-SiC nanocomposites prepared by precursor-derived ceramic method have the advantages of low pyrolysis temperature, small particle size and uniform phase composition. Some studies have used solid polycarbosilane (PCS) as the precursor of SiC. However, it has problems such as high cost and need to add solvent. In this work, TaC-SiC nanocomposites were prepared by precursor-derived ceramic method with polytantaloxane (PTO) and vinyl-containing liquid polycarbosilane (LPVCS) instead of PCS as raw materials after 2 h pyrolysis at 1600 °C. The obtained TaC-SiC nanocomposites have a particle size of about 200 nm and a grain size of 15–40 nm, wrapped by 1–2 nm amorphous carbon shells, which is beneficial to inhibit grain growth. By analyzing the oxidation mechanism of TaC-SiC nanocomposites, it was found that higher SiC content was conducive to antioxidant, because the SiO2 protective layer formed by oxidation insulated O2 diffusion.