Zirconia Toughening Extends Refractory Service Life

The Challenge

Al2O3–CaAl12O19 composites are ideal high-temperature structural ceramics, but their poor thermal shock resistance limits application under thermal shock conditions. These materials are used in metal processing, glass manufacturing, and other industries where rapid temperature changes cause crack formation and material failure. Improving thermal shock resistance without sacrificing other properties is essential for expanding their use.

The Solution

This research prepared composites from ferrotitanium slag, adding 12.5 wt.% unstabilized monoclinic zirconia for reinforcement. The GrindoSonic MK7 enabled measurement of elastic modulus before and after thermal cycling, quantifying damage accumulation through property degradation and assessing how crack formation affects material stiffness. Systematic analysis of phase compositions and microstructural evolution revealed the crack propagation resistance mechanisms.

Results

Enhanced thermal shock resistance results from multiple crack propagation resistance mechanisms, including stress-induced tetragonal to monoclinic phase transformation in t-ZrO2 and microcracking associated with m-ZrO2. Coarsened ZrO2 particles doped with TiO2 from the ferrotitanium slag are beneficial to both mechanisms. This understanding enables development of more durable refractories for high-temperature industrial applications.