Synthesis of ultrafine TaC–5 wt.% Co composite powders by the spray-carbothermal process

Ultrafine tantalum carbide (TaC)–5 wt.% Co composite powders were synthesized by a spray-carbothermal process, which includes (i) preparation of precursor powder by spray drying of a liquid solution of tantalum oxalate and cobalt nitrate hexahydrate, (ii) calcination to evaporate volatile components in the precursor powder and synthesis of nanostructured tantalum–cobalt composite oxides and (iii) ball milling with carbon, and subsequent carbothermal reaction in hydrogen. The formation temperature of TaC in this process (1050 °C) is significantly lower than that in the conventional method (1500 °C). The observed particle size of TaC–Co composite powders was smaller than 200 nm.