Effect of Carbon Nanostructures on Low Carbon Magnesia-Carbon Refractories Manufactured Using Slip-Casting as an Alternative Method

Abstract

Magnesia-Carbon (MgO-C) refractories are widely used in the steel industry due to their exceptional properties, including high corrosion resistance, low wetting angle with molten metal and slag, and excellent thermal shock resistance. This study aims to reduce the carbon content of MgO-C refractories from 20 wt% to 3 wt% by incorporating carbon nanostructures such as graphene, nano graphite, and carbon nanotubes. The use of these nanostructures was intended to enhance oxidation resistance and mechanical performance while maintaining thermal shock resistance. Binderless refractories were successfully fabricated using the slip-casting method. Key properties, including thermal shock resistance, oxidation behavior, and phase formation, were systematically evaluated using X-ray diffraction (XRD), thermogravimetry (TG), scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDS). Obtained results demonstrate that reducing graphite content significantly improves mechanical strength but compromises thermal shock resistance. However, the addition of 0.1 wt% graphene, nano graphite, and carbon nanotubes increased the residual strength of refractory samples after thermal shock to 69%, 88%, and 89%, respectively. Additionally, oxidation penetration depth was reduced to 38%, 41.5%, and 61.5% of the depth observed in samples without carbon nanostructures. These findings suggest that further optimization, including the addition of metal additives and solvent composition adjustments, could establish binderless magnesia-carbon refractories as a promising alternative to conventional refractories.