The Effect of Raw Material Ratios on the Fe-TiC/Al2O3 Composite Formation Mechanism

Ilmenite, aluminum and graphite have been used to produce in-situ Al2O3/TiC–Fe composites. Al2O3/TiC-Fe composites are used as cutting tools for machining gray cast iron and steels. Very few publications can be found in the literature discussing the effect of aluminum and graphite molar ratio on the formation mechanism of Al2O3/TiC–Fe composites. Therefore, the present research is an effort to make this issue clear. To achieve this goal, in this research, at first, the mechanism of the Fe- TiC/Al2O3 composite formation from ilmenite, aluminum and graphite mixture with a molar ratio of 1:2:1 was clarified. Then the samples with different molar ratios of aluminum and graphite were prepared. Since interpreting the results of the system in which the molar ratios of aluminum and graphite have been changed simultaneously, was complicated, both of the aluminum and graphite new ratios were changed separately in this work. The samples were heat treated at 1300°C to make sure that all reactions are done. The final products were analyzed with XRD and SEM. It was found that the optimum molar ratio of ilmenite, aluminum and graphite mixture is 1:2:1 because undesired compounds were not detected in the products. Compared with the ratio of 1:2:1, increasing the aluminum content of the raw materials caused the TiAl3 formation while insufficient aluminum did not allow the reactions to be completed. It was also found that using more graphite content, leads to the formation of Fe-C compounds while less graphite will result in uncompleted reaction.