Enhanced thermal shock resistance of low-carbon MgO–C refractories with SiC/MgAl2O4 nanocomposite powder

Abstract

To enhance the thermal shock resistance of low-carbon MgO–C refractories, SiC nanowires incorporated SiC/MgAl₂O₄ composite reinforcer were introduced. The effect of SiC/MgAl₂O₄ on the mechanical properties, thermal shock resistance, oxidation resistance and slag resistance of low-carbon MgO–C refractories was explored. The results showed that the low-carbon MgO–C sample incorporated with 9 wt.% SiC/MgAl₂O₄ (M9) displayed optimal overall properties, with 28% higher residual strength ratio, 59% lower oxidation index, and 18% reduced corrosion area compared to the reference sample M0. The increased residual strength ratio is mainly attributed to the synergistic effect of SiC nanowires and rod-shaped MgAl₂O₄, which facilitate crack deflection and branching, and energy dissipation through bridging and pull-out mechanisms, collectively contributing to matrix toughening. Besides, M9 (3 wt.% graphite) demonstrates better mechanical strength, oxidation resistance, and slag resistance compared to high-graphite samples (10 wt.% graphite), highlighting the significant potential of SiC/MgAl₂O₄ composite reinforcer in developing sustainable low-carbon refractories.