Mechanosynthesis of TaC-WC powders under environmental conditions and their consolidation via electric arc furnace

Abstract

In this study, tantalum carbide (TaC) was synthesized using an innovative approach that synergistically integrates mechanosynthesis and electric arc furnace processes. By employing high-energy ball-milling (HEBM) for 50 min under environmental conditions, TaC-WC powders were successfully synthesized, using a powder mixture of tantalum and carbon in a 1:1 stoichiometric ratio. This method yielded a composition of 72.5 wt.% TaC and 27.5 wt.% WC, with an average particle size of 0.7±0.3 µm. The use of an electric arc furnace led to the fabrication of a highly dense material with a relative density above 98%. Notably, WC derived from the mechanical milling material served as an effective sintering aid. X-ray photoelectron Spectroscopy (XPS) results indicated the formation of metal oxides on the surface of the sample, and despite the presence of these oxides, the density of the material remained uncompromised. Furthermore, X-ray diffraction (XRD) analysis after the electric arc furnace treatment demonstrated the preservation of the TaC and WC phases. Mechanical properties, including Vickers hardness, Young’s modulus and fracture toughness were 22.8±0.5 GPa under an applied load of 9.8 N, 539 GPa and 6.6 MPa m1/2, respectively. The results underscore a novel and efficient synthesis route for TaC-WC with enhanced mechanical properties and high density, which are crucial aspects for applications in ultra-high temperature ceramics.