TaC-WC synthesis by a new approach of mechanical milling and low-temperature spark plasma sintering

Abstract

Herein, TaC was synthesized by high-energy ball milling (60 and 120 min), employing a 1:1 stoichiometric ratio of tantalum and graphite. WC derived from milling material served as a sintering aid. This process yielded average particle sizes of 1.4±0.9 µm at 60 min and 0.9±0.6 µm at 120 min. TaC-WC powders were consolidated via spark plasma sintering at 1331 °C under 50 MPa, ensuing in materials with relative densities of ∼97% and ∼95% for 60-minute and 120-minute samples, respectively. Vickers hardness showed impressive results; the 60-minute sample presented a hardness of 17.7±0.8 GPa at 9.8 N and 27.9±0.6 GPa at 0.49 N, while the 120-minute sample presented a hardness of 18.9±0.5 GPa at 9.8 N and 23.1±0.9 GPa at 0.49 N. These values are comparable to materials manufactured for longer mechanical treatment and higher sintering temperatures (>1700 °C). The combination of these two techniques enabled the development of dense materials with high hardness.