Abstract: Effect of Nano-Silica on the Properties of In-situ Synthesized Alumina-Based Ceramic Core Composites Jinju Du Wei Li (South China Normal University, Guangzhou 510631, China ) Abstract: A ceramic core for use in the investment casting of metals sintered at 1300, 1400, and 1500 oC for 5 h were prepared and the phases were characterized by X-ray diffraction (XRD). Effect of nano-silica percentages on the properties of ceramic core was discussed. The properties of these materials were discussed. The results indicated that the presence of nano-silica has an effect on the microstructure of the core, densification, creep deformation, and linear expansibility of aluminum ceramic core. The creep deformation decreases with increase of the nano-silica contents and sintering temperature.