Mechanism, Prosperities and Microstructure of Titanium Carbide-Iron Metal-Ceramic from Ilmenite by in-situ Carbothermic Reduction

摘要

The fabrication of titanium carbide-iron metal ceramic was reported in this paper. The mainly starting materials are ilmenite (FeTiO{sub}3) and graphite. Synthesis and sintering were accomplished unanimously in the vacuum resistance furnace. The reaction forming mechanism was studied through various analytical methods including DTA, XRD and SEM. It is showed that the mechanism of the carbothermic reduction process is complicated and multistage. The reaction process was found as following: an initial, rapid reduction of ilmenite to elemental iron and a series of lower titanium oxides; the gradual removing of oxygen from the Ti{sub}xO{sub}y phases step by step until the formation of TiC apparently in subsequent heating; TiC crystallite growth occurs with the increasing temperature. The investigation of microstructure and properties of titanium carbide-iron composites found that additives Mo and Ni have a beneficial effect on the microstructure and properties of titanium carbide-iron composite. Product with 8wt% Mo additive had high density of 5.848 g/cm{sup}3, Rockwell hardness of 88.3 and good microstructure. Adding Mo and Ni (1:1) together also has a marked beneficial effect on titanium carbide-iron composites.