Utilization of sepiolite in the synthesis of porous cordierite ceramics

Porous cordierite ceramics were prepared using sepiolite source of MgO and SiO₂ and alumina as starting materials by simple dry-pressing/sintering. The sepiolite/alumina green bodies were sintered at 1100-1350°C for 2h. The characterization was focused on thermal analysis, phase evolution, sintering behavior, thermal expansion and micro-structural changes using DSC/TG, XRD, dilatometry and SEM. α-Cordierite was formed above 1200°C, the amount of which increased steadily with the sintering temperature. Increasing sintering temperature also improved the densification (especially above1000°C), and decreased the thermal expansion (especially above 1200°C). Porous cordierite with a bimodal pore size distribution (1.4-1.9μm and 10μm) was prepared with cornstarch as pore-former.