Comparison of physical properties of Ta-Cu-X contact materials with mixing of additives

W–Cu materials dominate the high-current electrical contact material market despite their limited machinability. This study investigates a potential alternative contact material, tantalum‑copper-X (Ta-Cu-X; X = tungsten carbide (WC) or cerium oxide (CeO₂), in which Ta imparts excellent machinability and thermal resistance while the oxides and carbides impart excellent mechanical properties. CeO₂ and WC were selected as additives owing to their favorable chemical stability. Ta-Cu-X powder mixtures were prepared in order to facilitate the incorporation of different ratios of additives into molded and sintered Ta–Cu composites with a Ta:Cu wt% ratio of 40:60. The electrical conductivity, arc resistance, and hardness of the resultant composites were investigated. The electrical and thermal conductivities of the composites decreased with increasing additive content; however, their hardness increased. An optimum combination of electrical conductivity (52.8% IACS (International Annealed Copper Standard)), thermal conductivity (194.2 W/m∙K), and hardness (163.5 HV) was demonstrated by the composite containing 0.5% CeO₂; these properties compare favorably with those of commercially available electrical contact materials.