Nanoscale toughening of low carbon Al2O3‐C refractories by means of SiCnw/Al2O3 composite reinforcement

Abstract

AbstractTo improve the thermal shock resistance of low carbon Al2O3‐C refractories, SiC nanowires (SiCnw) containing SiCnw/Al2O3 composite reinforcement were introduced. The specific fracture energy of the Al2O3‐C refractory matrix was obtained by statistical grid nano‐indentation. The reinforcement mechanism of SiCnw/Al2O3 on thermal shock resistance of refractories was investigated. The results revealed that the matrix‐specific fracture energy of A6 (6 wt% SiCnw/Al2O3 added) was 217 N/m, which was 58.4% higher than reference sample A0 (137 N/m) and 18.6% higher than MA6 (183 N/m, 6 wt% SiC/Al2O3 added). A6 showed the highest residual strength ratio of 49.8%, which was 114.7 % higher than A0 (23.2%) and 82.4 % higher than MA6 (27.3%). The components with different morphology in SiCnw/Al2O3 cluster, especially SiC nanowires, promote the generation of microcracks, crack multi‐deflection, and branching, which toughen the matrix and improve the thermal shock resistance of refractories. In comparison to the literature, A6 showed a higher rising in residual strength ratio than those with higher graphite content (4 wt% and 20 wt%), which will greatly reduce the consumption of carbon‐containing refractories and contribute to the reduction of CO2 emission.