Ti₃C₂T_X MXene—Silicon Carbide for High Temperature Applications

2D transition metal carbides (MXenes) are promising as additives in ceramic systems due to their high temperature phase stability of their resulting carbides and in-plane stiffness. High temperature annealing studies on Ti₃C₂T<i>_x</i> MXene have shown phase transformation to lamellar, non-stoichiometric cubic TiC<i>_y</i>. Silicon carbide (SiC) is known for the high hardness, high wear resistance and stability for a wide range of temperatures. However, the low fracture toughness limits monolithic SiC applications. A ceramic structure with layers of TiC can potentially improve the fracture toughness of SiC. In the present work, we investigated the tailorable preparation of green bodies of nanometer thin Ti₃C₂T<i>_x</i> MXenes with SiC powders via electrostatic self-assembly, in a surfactant-free, scalable aqueous media. Because of negative surface charges (zeta potential of -35 to -50 mV) of MXene flakes, they can be mixed with SiC in pH ~ 5 and lead to a uniform self-assembly of Ti₃C₂T<i>_x</i> and SiC, thereby eliminating the need for additional surfactants. Prepared green bodies are sintered by pressure-assisted pulsed current sintering. Addition of 2D MXene fillers into SiC system improves the densification and lowers the sintering time and temperature. The effect of temperature, dwell time and pressure on the densification of the green bodies are studied, which can provide insights on the role of MXenes in improving SiC mechanical properties and their stability.