| Abstract Scope |
Ultra-high temperature ceramics (UHTCs), including carbides, nitrides, and borides of group 4 and 5 transition metals, offer high melting points, oxidation resistance, and thermal shock tolerance, making them ideal for hypersonic and re-entry applications. Direct Ink Writing (DIW) was employed to fabricate complex, high-density (>13.8 g/cm³) tantalum carbide (TaC) components. A colloidal suspension with >85 wt% TaC, 3 wt% glycerol, and 1 wt% polyacrylic acid (PAA) was prepared. Two sintering methods—pressured Spark Plasma Sintering (SPS) and pressureless Spark Plasma Sintering (PSPS)—were compared. Scanning electron microscopy (SEM) revealed higher porosity and spherical pits in PSPS samples, caused by gas evolution during binder burnout. Pressured samples exhibited higher hardness (10.42 ± 1.18 GPa) than pressureless ones (9.60 ± 0.84 GPa). Nanoindentation showed elastic moduli of 246.61 ± 21.62 GPa (SPS) and 119.42 ± 20.56 GPa (PSPS). These results highlight DIW combined with SPS as a viable pathway for producing high-performance TaC components with controlled microstructures. |