분무건조법에 의해 제조된 Ti-Co-O계 산화물 분말의 환원/침탄반응에미치는 코발트 산화물의 영향

Abstract

In the present study, the focus is on the effect of cobalt oxide powder in the carbothermal reduction of the titanium-cobalt-oxygen based oxide powder by solid carbon for the optimizing synthesis process of ultra fine 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 flowing argon atmosphere. Changes in the phase structure and thermal gravity of the mixture during carbothermal reduction were analysed using XRD and TGA. Titanium-cobalt-oxygen based oxide powder desalted at 600℃ had a mixture of TiO2 and Co3O4. And the one desalted at 800℃ had a mixture of TiO2 and CoTiO3. In the case of the former powder, the reduction of cobalt oxide powder in the titanium-cobalt-oxygen based oxide powder occurred at lower temperature than the latter one. However, the carbothermal reduction of titanium dioxide powder in the titanium-cobalt-oxygen based oxide powder with a mixture of TiO2 and Co3O4 occurred at higher temperature than the one with a mixture of TiO2 and CoTiO3. And also, the former powder showed a lower TiC formation ability than the latter one.