Nano- and micrometre additions of SiO_2, ZrO_2 and TiO_2 in fine grained alumina refractory ceramics for improved thermal shock performance

摘要

The present contribution investigates the influence of micro-metre- as well as nano-metre-additions of zirconia (ZrO_2), titania (TiO_2), silica (SiO_2) and magnesia (MgO) into alumina-rich fine grained ceramic materials for refractory applications. Slip casted samples in the system alumina-zirconia-titania (AZT), alumina-zirconia-titania-silica (AZTS) and alumina-zirconia-titania-magnesia (AZTM) were sintered and the physical as well as mechanical properties were investigated as fired and after thermal shock treatments. The generation of a micro-crack network after sintering due to the formation of phases with different thermal expansion coefficients and the formation and decomposition of aluminium titanate (Al_2TiO_5) before and after thermal shock exposure leads to higher strengths after thermal shock attack.