Synthesis and Characterization of TiC-Ni Hybrid Systems Prepared through Different Chemical Routes

Nanomaterials are of great interest due to the wide range of properties they exhibit in multiple applications, including less explored fields such as the reinforcement of steels and cast irons. A promising approach to improve the mechanical performance of iron-based alloys is the addition of nanoparticles (NPs) with high hardness and thermal stability, such as titanium carbide (TiC). However, the effectiveness of this method is often limited by the poor physical and chemical compatibility between ceramic particles and molten alloys, which causes the particles to float during their addition to the molten metal. In this context, the synthesis of ceramic-metallic hybrid particles at the nanoscale emerges as an effective strategy to improve the interfacial compatibility between both materials. More specifically, this work employed TiC-Ni composite systems prepared through different laboratory-scale chemical routes using commercial TiC nanoparticles (approximately 20 nm in diameter).

TiC-Ni hybrid systems were obtained through different synthesis routes that promoted the deposition of nickel (Ni) nanoparticles on the surface of commercial TiC nanoparticles. Ni(II) precursors were used in several reduction methods, including chemical reduction with sodium borohydride, hydrazine and aluminium, as well as the thermal decomposition of organometallic precursors in high-boiling-point organic solvents. Different energy input strategies were also employed, such as conventional heating, microwave-assisted heating and ultrasonic agitation, to evaluate their effect on nanoparticle formation. The presence of TiC did not inhibit the formation of Ni nanoparticles and successfully led to the production of TiC-Ni composite systems with different sizes and morphologies. Several Ni structures were obtained, including face-centred cubic (FCC), hexagonal close-packed (HCP) and amorphous structures.

The resulting materials were characterised by transmission electron microscopy (TEM), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM).

The incorporation of these TiC-Ni hybrid systems into cast iron matrices and the evaluation of their effect will be addressed in future work.