Ca_7ZrAl_6O_(18) acting as a hydraulic and ceramic bonding in the MgO-CaZrO_3 dense refractory composite

摘要

In this paper, the results of an experimental study concerning the dehydration behavior of the hydrated MgO-CaZrO_3-Ca_7ZrAl_6O_(18) green compacted sample are presented. Hydrated MgO-CaZrO_3-Ca_7ZrAl_6O_(18) mixture products were studied by XRD, DTA-TG and FT-IR after 24 h of curing and hydration at room temperature. According to the XRD examination it has been found that brucite, Mg(OH)_2, was only identified as a crystalline hydrated phase. The presence of the metastable hexagonal hydrates (CAH_(10), C_2AH_8) in the hydrated sample were identified by FT-IR and DTA-TG studies. The MgO-CaZrO_3-aluminates dense refractory composite material was investigated by XRD, SEM/EDS and mercury porosimetry. The XRD and SEM/EDS results showed that the compound with chemical composition of Ca_(12)Al_(14)O_(33) occurred in the MgO-CaZrO_3-Ca_7ZrAl_6O_(18) matrix. By applying the mercury intrusion porosimetry technique, the heterogeneous pore size distribution of the composite was determined.