Abstract

Ultrafine TiC-5%Co powders were synthesized by spray drying of aqueous solution of TiO(OH)_2 slurry and cobalt nitrate, followed by calcination and carbothermal reaction. The oxide powders with carbon powder was reduced and carburized at 900°Csim1250°C under hydrogen atmosphere. During reduction, CO gas was mainly evolved by reducing reaction of oxides. Ultrafine TiC-5%Co powders were easily formed by carbothermal reaction at 1250°C due to using ultrafine powders as raw materials. The ultrafine WC-TiC-Co alloy prepared by sintering of mixed powder of ultrafine WC-13%Co powder and ultrafine TiC-5%Co powder has higher sintered density and mechanical properties than WC-TiC-Co alloy prepared by commercial WC, TiC and Co powders.

• Keywords: Ultrafine powder;TiC;Carbothermal reaction;Hard metals;WC-TiC-Co;