MECHANO-THERMAL REDUCTION OF HEMATITE AND ANATASE MIXTURE BY TWO DIFFERENT FORMS OF CARBON AS REDUCTANT FOR IN-SITU PRODUCTION OF Fe-T iC - NANO CRYSTALLINE COMPOSITE

In this research, two different carbonaceous materials (Graphite:G and Petrocoke:P) were separately compared in terms of the carbothermic reduction of hematite and anatase in order to synthesize Fe-TiC nanocrystalline composite by mechanically activated sintering method. Powders were activated in a planetary high-energy ball mill under argon atmosphere for ۰, ۲, ۵, ۱۰,and ۲۰ h. Then, the activated powders were analyzed by XRD and SEM to investigate phase constituents and microstructure of the mixtures. Results proved that Fe ۲ O ۳ and TiO ۲ were not reduced by carbonaceous materials even after ۲۰h of milling. SEM investigations showed that G-mixture was more homogenous than P-mixture after ۲۰h of milling, meaning that graphite-anatase-hematite was mixed satisfactorily. Thermogravimetry analysis was done on ۰ and ۲۰h milled powders. TG and DTG curves showed that mechanical activation led to almost ۳۰۰°C decrease in the reduction temperature of hematite and anatase in both mixtures. In the next step, the powders were sintered in a tube furnace under argon atmosphere. In the G-mixture, anatase was reduced to titanium carbide at ۱۱۰۰°C but, in the P-mixture, temperature of ۱۲۰۰°C was essential for completely reducing anatase to titanium carbide.Results of phase identification of the sintered powders showed that anano-crystalline ironbased composite with titanium carbide, as the reinforcement was successfully synthesized after ۲۰ h high-energy milling of the initial powders and subsequent sintering occurred at ۱۲۰۰˚C for ۱h

Keywords:

Mechanical Activation , Heat Treatment , Fe-TiC , Nano-crystalline Composite , Petrocoke , Graphite.