New route to densify tantalum carbide at 1400 °C by spark plasma sintering

Tantalum carbide with a TaC0.9 composition was sintered to 96% relative density by spark plasma sintering at 1400 °C for 5 min, using commercial micrometric Ta and TaC powders as the starting materials. This achievement was dependent on the delicate rearrangement of the heating process which limits evaporation–condensation and promotes the mass transportation in association with 0.9TaC + Ta = TaC0.9 reaction. The dense TaC0.9 ceramic had a uniform microstructure composed of equiaxed grains, and showed flexure strength up to ∼498 MPa.

► Tantalum carbide with a TaC0.9 composition was densified by SPS at 1400 °C for 5 min. ► The low temperature favored prevention of the harmful evaporation–condensation. ► Elimination of the residual pores was due to improved intimate particle contact.