SELF-HEALING MICROSTRUCTURE: THE UTMOST REFRACTORY TOUGHNESS MECHANISM

Refractories are often exposed to thermal variations during their operational cycle, such as in torpedo cars and iron ladles, where molten metal is loaded and unloaded at a high frequency basis. Dealing with that aggressive thermal shock is not straightforward and the most common approach for these materials is to optimize the carbon sources, increasing the thermal conductivity of the bricks and reducing the thermal gradient between the hot and cold faces. If, on one hand, the material becomes more resistant to thermal shock damages, on the other hand, its higher conductivity imposes a negative consequence: higher thermal loss during operation. In this work, inspired by intelligent microstructures with the ability to adapt to the most severe environmental conditions, an innovative approach was evaluated, aiming at obtaining an Al2O3- SiC-C brick formulation designed to present a self-healing behavior, without variation in the carbon sources or content. The new developed structure successfully regenerated the cracks initiated during thermal cycles, resulting in an even tougher material after thermal shock tests. Other properties such as mechanical, oxidation, and corrosion resistance also showed promising results, pointing out the birth of a smart self-healing technology, able to completely change the role of refractories in thermal cyclic operations.