The present research focuses on the development of alumina‐nano‐zirconia composite refractory. Alumina powders were mixed with varying percentage of nano‐zirconia, compacted by the slip casting method, and sintered in the temperature range of 1400°C–1700°C for 4 h to obtain Al 2 O 3 ‐(x)ZrO 2 (x = 0.25, 0.50, 0.75, and 1 wt.%) composites. The impact of nano‐zirconia incorporation on the mechanical and fracture properties of the composites was systematically examined. The slight addition of nano‐zirconia resulted in an increase in bulk density and hardness, due to enhanced packing density and grain boundary pinning effects. Simultaneously, apparent porosity decreased, although compressive strength and fracture toughness showed significant improvement, particularly with 0.50–0.75 wt.% zirconia concentrations due to mechanisms such as crack deflection, phase change toughening, and load transfer. The composite sintered at 1550°C exhibited the optimal equilibrium of mechanical characteristics. The improved properties are attributed to the uniform dispersion of ZrO 2 , which refined the grain structure and enhanced the densification of the Al 2 O 3 matrix. Change in the fracture mechanism from intergranular to mixed state was observed with the incorporation of n‐ZrO 2 .
Paul et al. (Thu,) studied this question.