LAUSR

Porous mullite (3Al2O3·2SiO2) ceramics were fabricated by mixing a commercial alumina (Al2O3) with silica (SiO2) from different sources, a commercial silica and rice husk silica (RHSiO2), in this study. Activated carbon (AC) was added as a pore former. Different compositions of starting raw materials used were fabricated to study pore characteristics and mullite phase evolutions. The pressed samples were sintered in an electric oven at 1450 °C for 4 h with a heating and cooling rate of 120 °C/min. An X-ray diffractometer (XRD) was used to characterize mullite phase present. Microstructures of pores formed at the external and internal surfaces of the sintered mullites were mainly investigated using scanning electron microscopes (SEMs). Evaluation of pore sizes and their distributions on the surfaces was performed using an image analysis technique based on SEM images observed on the top and cross-sectional surfaces of the sintered mullites. The quantitative information on pore characteristics related to starting chemicals, mullite densities, and mechanical properties has been extensively discussed.