Thermal plasma in situ processing of titanium nitride and titanium carbide reinforced iron alloy ultrafine composites from ilmenite

Ultrafine particles synthesis of iron alloy-titanium nitride and iron alloy-titanium carbide composites using a non-transferred direct current (DC) plasma processing method were studied. Ilmenite powder was used as a raw material. Reactant gas for synthesizing iron alloy-titanium carbide composites was methane and for synthesizing iron alloy-titanium nitride composites were methane and nitrogen gases. The standard Gibbs energy minimization method was used to calculate the thermodynamic equilibrium compositions of the system. By allowing the equilibrium species to react as the temperature in the system is reduced, the most important gas phase reaction and the supersaturation of the reacting chemical vapor were predicted. Mathematical models of transport phenomena were established and solved. Three thermocouples and a computer data acquisition system were used for obtaining the experimental data and model verification. It was found that experimentally measured temperature values agreed well with those from the calculation based on the model.; The thermal plasma reactor was designed, fabricated, and operated for synthesizing of ultrafine composites. By using this reactor, particle iron-titanium nitride and iron-titanium carbide composites powders were synthesized and collected. TiN and TiC particle size were in the range of 1–10 μm and 200 nm-5 μm, respectively. Scanning electron microscope (SEM), energy-dispersive X-ray Spectrometer (EDS), and X-rays diffraction analysis were used for product characterization.; Results show a maximum recovery of 100% of TiN and Fe for Fe-TiN composites and 100% TiC with 86.5% Fe and 13.5% FeTi for Fe-TiC composites. Series of experiments have been carried out in order to study the effect of variables. Results show that the higher nitrogen mole ratio at enough amount of methane to reduce oxygen in the system, the higher percent recovery of TiN. Also, the lower feeding rate and the higher power input, the higher TiN. The variables have reverse effect to percent recovery of TiC.