Preparation of TiC powders by carbothermal reduction method in vacuum
(1. National Engineering Laboratory for Vacuum Metallurgy, Kunming 650093, China;
2. Key Laboratory of Vacuum Metallurgy for Nonferrous Metal of Yunnan Province, Kunming 650093, China;
3. Faculty of Materials Science and Engineering, Kunming University of Science and Technology,
Kunming 650093, China)
2. Key Laboratory of Vacuum Metallurgy for Nonferrous Metal of Yunnan Province, Kunming 650093, China;
3. Faculty of Materials Science and Engineering, Kunming University of Science and Technology,
Kunming 650093, China)
Abstract: The preparation of fine TiC powders by carbothermal reduction of TiO2 in vacuum was investigated by XRD, SEM, XRF and laser particle sizer. Thermodynamic analysis indicates that it is easy to prepare TiC in vacuum and the formation sequence of products are Ti4O7 (Magneli phase), Ti3O5, Ti2O3, TiCxO1−x and TiC with the increase of reaction temperature. Experimental results demonstrate that TiC powders with single phase are obtained with molar ratio of TiO2 to C ranging from 1:3.2 to 1:6 at 1 550 °C for 4 h when the system pressure is 50 Pa, and TiC1.0 is gained when the molar ratio of TiO2 to C is 1:4 and 1:5. In addition, fine TiC1.0 powders (D50 equals 3.04 μm) with single phase and low impurities are obtained when the molar ratio of TiO2 to C is 1:4. SEM observation shows that uniform shape, low agglomeration, and loose structure are observed on the surface of block product.
Key words: titanium dioxide; titanium carbide; vacuum; carbothermal reduction method