Synthesis and formation mechanism of ZrC–SiC–TiC ceramic powders with high-sinterability via sol-gel process and carbothermal reduction

In this work, high-sinterability ZrC–SiC–TiC ceramic powders were synthesised through a sol-gel approach coupled with subsequent carbothermal reactions. Specifically, MgCl 2 was utilised as an additive to enhance the sintering activity of the powders. Experimental results revealed that the introduction of Mg and variation in Zr/Ti molar ratios significantly influenced the phase and morphological evolution of the precursor. In the form of a Mg–Si–O liquid phase, Mg promoted carbothermal reduction and solid-solution reactions. It ultimately remained as amorphous Mg–Si–O oxide in the final ZrC–SiC–TiC ceramic powders, effectively improving the sintering activity of ceramic powders. Consequently, dense Mg-modified ZrC–SiC–TiC ceramics with high relative density up to 99.2 % were successfully fabricated by spark plasma sintering at 1700 °C and 30 MPa.