Nanoscale reinforcement efficiency analysis in Al2O3-MgO-C refractory composites

This work proposes a materials design parameter, known as the reinforcement index (Ri) to classify the re-inforcements in Al2O3-MgO-C refractory system, based on their performance. They are tensile reinforcements (Ri>+1, e.g., YAG, EG\YAG) that favour the refractory load-bearing capacity enhancement while compared with compressive and neutral reinforcements. Two kinds of tensile reinforcements, namely, pure YAG (yttrium aluminium garnet; Y3Al5O12) and EG\YAG (expandable graphite (EG) hybridized YAG) nanoscale powders were prepared in-house and evaluated their performance in a high-temperature treated Al2O3-MgO-C refractory system at 1600 degrees C. For a given reinforcement concentration (Xf = 0.003-0.02), the experimental findings based on structural properties, mechanical reliability, and microstructure stability corroborated that EG\YAG as an efficient reinforcement than pure YAG. These reinforcement benefits were attributed to the core-sheath micro-structure formed with EG dispersed YAG framework. Implication of these results to design and development of thermal shock resistant refractory compositions with end-use in steel making products are discussed.

Automated summary

This study proposes a materials design parameter, Ri, to classify the reinforcements in the Al2O3-MgO-C refractory system based on their performance. The experimental results show that both pure YAG and EG\YAG nano-powders are effective reinforcements, but EG\YAG is more efficient than pure YAG. This efficiency is attributed to the formation of a core-sheath microstructure with EG dispersed YAG framework.