Abstract

In the present study, the focus is on the analysis of carbothermal reduction of the titanium-cobalt-oxygen based oxide powder by solid carbon for the optimizing synthesis process of ultra fined TiC/Co composite powder. The titanium-cobalt-oxygen based oxide powder was prepared by the combination of the spray drying and desalting processes using the titanium dioxide powder and cobalt nitrate as the raw materials. The titanium-cobalt-oxygen based oxide powder was mixed with carbon black, and then this mixture was carbothermally reduced under a flowing argon atmosphere. The changes in the phase structure and thermal gravity of the mixture during carbothermal reduction were analysed using XRD and TGA. The synthesized titanium-cobalt-oxygen based oxide powder has a mixture of TiO_2 and CoTiO_3. This oxide powder was transformed to a mixed state of titanium car-bide and cobalt by solid carbon through four steps of carbothermal reduction steps with increasing temperature; reduction of CoTiO_3 to TiO_2 and Co, reduction of TiO_2, to the magneli phase(Ti_nO_2n-1, n>3), reduction of the mag-neli phase(Ti_nO_2n-1, n>3) to the Ti_nO_2n-1(2≤n≤3) phases, and reduction and carburization of the Ti_nO_2n-1(2≤n≤3) phases to titanium carbide.

• Keywords: Titanium carbide;Cobalt;Spray drying;Carbothermal reduction;Titanium oxide;Hard materials;