Nanocharacterization of spark plasma sintered TiB₂–SiC–graphene composites

This investigation studies TiB₂–SiC–graphene ceramics in terms of microstructure and mechanical properties. Spark plasma sintering (SPS) at 1800 °C was employed as manufacturing route, and the as-sintered composite was studied using high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), X-Ray diffractometry (XRD), and nano-indentation. The system was found to be unreactive, and all results dismissed the in-situ nucleation of B₄C and TiC phases. Although TiO₂ and B₂O₃ surface impurities were mainly reduced upon the incorporation of graphene nano-platelets (GNPs), the presence of SiO₂ in the final microstructure was confirmed by both XRD and HRTEM methods. The TiB₂ phase achieved a hardness of 35 GPa and a Young modulus of 539 GPa, which were roughly 45% and 25% higher than those measured for the SiC phase.