Rheological properties and excellent thermal shock stability of Al2O3-SiC-C castables containing continuous TiC coated graphite

High-flux molten iron and intermittent circulation accelerated the damage process of Al2O3-SiC-C castables under alternating thermal stress. A continuous TiC coated graphite was prepared using sol-gel combined with carbothermal reduction to investigate its influence on the flow properties, microstructure, mechanical properties and thermal shock resistance of Al2O3-SiC-C castables. The results show that a lower Ti/C molar ratio and higher heat treatment temperature are more favorable for the synthesis of TiC and the formation of a continuous and complete TiC coated graphite layer on the graphite surface. The introduction of TiC coated graphite significantly enhance the mechanical properties and thermal shock stability of Al2O3-SiC-C castables, with a remarkable 227 % increase in residual strength after thermal shock. In addition, during the oxidation process of the samples with TiC coated graphite, TiO2 generated from the oxidation of TiC fills the pores and facilitates the growth of Al6Si2O13, which enhances the tightness of the bonding of the castable matrix, thus contributing to the improvement of the overall performance.