Effect of C/MgO nanocomposite powders on the properties of low-carbon MgO–C refractories

Abstract

To produce high performance low carbon MgO–C refractories, the combustion synthesized MgO nanofibers containing C/MgO composite powders (SCM) were introduced. The effect of SCM on the mechanical properties, thermal shock resistance, oxidation resistance and slag resistance of MgO–C refractories has been studied, along with exploring the toughening mechanism on thermal shock resistance. The results showed that the refractories containing 6 wt% SCM (M6) exhibited the most favorable comprehensive properties. Compared to reference sample M0, M6 showed significant enhancements in thermal shock resistance, oxidation resistance, and slag resistance by 38.6%, 29.8%, and 23.9%, respectively. Notably, the unique microstructure of MgO nanofibers and carbon encapsulated MgO played a crucial role in facilitating crack deflection and branching, which promote the generation of microcracks and the consumption of strain energy. These mechanisms contributed to the improvement in thermal shock resistance of refractories.