Ti₃SiC₂ MAX phase: Sol–gel processing, characterization, and sinterability

In this work, Ti₃SiC₂ (TSC) MAX phase precursors were synthesized using a sol–gel method, presenting an innovative alternative to address the challenges of conventional element-based high-temperature powder synthesis, including phase purity limitations and decomposition problems. The 3:1 Ti/Si-alkoxide ratio provided the best results for starting materials with different stoichiometries (1:1, 3:2, 2:1, and 3:1). Fourier transform infrared (FTIR), thermogravimetric (TG), and X-ray diffraction (XRD) analyses confirmed the partial hydrolysis and condensation of the precursors, as well as the formation of Ti–O–Si bonds with organic groups. TSC raw materials were subjected to heat treatment at 1150–1350°C for 30–60 min. The most successful formation of Ti₃SiC₂ was achieved at 1350°C for 60 min, and MnO₂ was employed in a separate crucible as an oxygen scavenger to suppress oxide formation. According to Raman, scanning electron microscopy (SEM), transmission electron microscope (TEM), and XRD analyses, a layered Ti₃SiC₂ with a micron size was synthesized. The purity of the synthesized Ti₃SiC₂ was determined to be above 96 wt%. Furthermore, powders consolidated by spark plasma sintering (SPS) at 1300°C under 40 MPa for 5 min achieved a relative density of 97%, demonstrating good sinterability. These findings highlight the sol–gel method as a promising approach for producing high-purity MAX phase precursors.