The optimization of the microstructure and phase assemblage of high chromia refractories

The effect of Al2O3 and ZrO2 addition in chromia-based refractories was inv estigated. The strength of ZrO2-bearing chromia refractories was greatly en hanced by 4-8 wt% Al2O3 additive. In the range of 0-12 wt% ZrO2 addition, 6 wt% ZrO2 was most beneficial to the improvement in thermal shock resistanc e. Corrosion resistance was compared by exposing to three kinds of coal sla g with various CaO contents. As the substitution of ZrO2 for Cr2O3 increase d, slag penetration increased, particularly in the case of the slag contain ing similar to 16 wt% CaO. Considering the trade-offs between corrosion res istance, thermal shock resistance and mechanical properties, the optimum ph ase assemblage of high chromia refractories consists of the large granular Cr2O3 grains bonded by annular (Cr, Al)(2)O-3 grains and well-distributed f ine ZrO2 grains. (C) 1998 Elsevier Science Limited. All rights reserved.