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 degrees C for 30-60 min. The most successful formation of Ti3SiC2 was achieved at 1350 degrees 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 degrees 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.