China Nonferrous Metallurgy

So advantageous are TiC-based iron matrix composites in terms of high hardness, strength, good plasticity and toughness, and simple molding that they are widely used in industries such as aerospace, mechanical equipment, and automobiles. In the preparation process of existing TiC-based iron matrix composites, high-purity Ti powder, Fe powder, C powder, B4C powder and other materials are mostly selected for synthesis.In this study, vanadium-titanium iron concentrate and coal powder were used as the main raw materials, and a new type of TiC-based iron matrix composite was prepared by carbothermal reduction-acid leaching process. The effects of carbothermal reduction and acid leaching process parameters on the preparation of TiC-based iron matrix composites were investigated by single factor experiments.The results illustrate that temperature exerts a remarkable influence on the phase composition of the products. With the increase in temperature, Fe gradually changes from existing in the form of Fe_0.9Si_0.1 to Fe₃Si. Under the conditions of a ball-to-material ratio of 4∶1, a reduction temperature of 1550℃, and a reduction time of 30 minutes, the main components of the phase composition are Fe₃Si, Ti(C,N), excessive C, and MgAl₂O₄. By employing a 10% hydrochloric acid (HCl) solution, maintaining a solid-to-liquid ratio of 20∶1, setting the leaching temperature at 85℃, and conducting the leaching process for 120 minutes, the acid-leaching operation effectively removed the extraneous impurities. As a result, the TiC/Fe composite material was successfully fabricated.The morphology and particle size showed little change before and after acid leaching. The particle size was 22μm before acid leaching and 23μm after acid leaching. It should be noted that the reinforcing phase TiC in the prepared TiC/Fe composite material is impure and predominantly exists in the form of Ti(C,N). However, this problem can be effectively circumvented by selecting an appropriate raw-material-to-ball ratio, appropriately adjusting the carbothermal reduction time, and maximizing the carbothermal reduction temperature to the greatest extent possible.