Abstract

B4C additive was adopted to accommodate the structure evolution of MWCNTs in Si containing Al2O3-C refractories. The corresponding phase compositions and microstructures of Al2O3-C refractories were investigated by means of X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. The mechanical properties were investigated by means of three-point bending test and the thermal shock resistance was evaluated through traditional water quenching method combined with wedge splitting test. The results show that B4C additive prevents the structure transformation of MWCNTs at 1000 °C and suspends the transformation at 1200 °C attributes to the decreased SiO(g) pressure. Additionally, B4C favors the catalytic formation of new MWCNTs and quasi-graphene sheets. In comparison with the refractories containing Si additive alone, more residual MWCNTs and newly formed MWCNTs and graphene sheets in B4C and Si containing Al2O3-C refractories contribute to lower brittleness, leading to better thermal shock resistance.