Effects of SiCnw/Al2O3 composite powders on properties of Al2O3–SiC refractory castables

The SiCnw/Al2O3 composite powders synthesized through combustion synthesis method were added to the Al2O3–SiC refractory castables used in waste incinerators to improve their properties. The properties of Al2O3–SiC refractory castables with SiCnw/Al2O3 composite powders (0–8 wt%) were evaluated which contained apparent porosity, bulk density, mechanical strength, high temperature wear resistance, hot modulus of rupture, thermal shock resistance and slag corrosion resistance. The results showed that various properties of the castables were enhanced with the addition of SiCnw/Al2O3 composite powders. When 6 wt% composite powders were added, the hot modulus of rupture increased by 84.1% from 1.63 to 3.00 MPa, the high temperature wear volume decreased by 242.2% from 6.16 to 1.8 cm³, and the residual strength rate increased by 22.6% from 42.5% to 52.1%. Therefore, the properties of Al2O3–SiC castables were improved through the synergistic reinforcement effect of SiC nanowires and acicular mullite whiskers on the matrix.