SINTERING AND PERFORMANCE OF HIGH ALUMINA REFRACTORY WITH ZrO_2 ADDITION

摘要

Sintering behavior and performance of high alumina refractory based on the ternary subsystem MgAl_2O_4-CaAl_4O_7-CaAl_(12)O_(19) were investigated using ZrO_2 as an additive up to 8 wt.% by solid state reaction sintering. It was found that the added ZrO_2 could dissolve in the CA_6 grains in the form of a solid solution, which enhanced the isotropic growth of CA_6 grains and then improved the sintering. As a result, the densification process was improved and areas with enrichment of ZrO_2 showed a more compact structure. With further increase of ZrO_2 addition, tetragonal ZrO_2 were found to locate in the grain boundaries for exceeding the solid solubility limit, which enhanced the thermal shock resistance, indicating that addition of ZrO_2 exhibited a positive effect on sintering behavior and performance of this refractory. In addition, it is considered that the optimal amount of ZrO_2 addition was about 4% considering the performance together with the cost.