Mechanism and optimization of titanium carbide-reinforced iron composite formation through carbothermal reduction of hematite and anatase

This study investigated an optimization of titanium carbide-reinforced iron composite fabricated using a combination of powder metallurgy and carbothermal reduction of hematite-anatase mixture using 2k factorial design. The composite formation mechanism is described as well. Powders of hematite, anatase and graphite with mole ratio of 1:1:6 were mixed for 1 h together with 0 wt%, 1 wt% and 5 wt% FeCl3. The mixture was pressed at 5 MPa, calcined for 1 h at 1000 °C, 1100 °C or 1200 °C and sintered at 1200 °C. X-ray diffraction of the calcined powder showed that with increasing temperature TiO2 was reduced to TiC through formation of various suboxides (Ti3O5 and Ti2O3). Scanning electron microscope observation of the sintered composite indicated that addition of FeCl3 enhanced the formation of TiC in iron matrix. Consequently, microhardness and density of the sintered composite improved noticeably. Based on microhardness, green density and sintered density measurements, design of experiment analysis suggested that an increase in both FeCl3 content and calcination temperature increased the percentage of hematite and anatase reduction.