Effect of Y2O3 on the properties of Al2O3–SiC composite ceramics synthesized by the molten salt method

To delve deeper into the preparation process of Al 2 O 3 –SiC composite ceramics, Al 2 O 3 –SiC composite powder was in-situ synthesized by the molten salt method. Silica fume, aluminum powder, and carbon black were used as the raw materials, Y 2 O 3 as the catalyst, and NaCl–KCl as the molten salt media. The effects of synthesis temperature and Y 2 O 3 dosage on composite powder phase composition and microstructure were systematically investigated. The experimental results show that with the increase in the Y 2 O 3 dosage from 0 to 3 wt.%, the main crystalline phases are dominated by α-Al 2 O 3 and β-SiC phases, with whisker lengths of 0.5–3 μm and diameters of 20–70 nm. The synthesis mechanism of SiC whiskers indicates that the vapor–solid growth mechanism plays a dominant role in the synthesis process.