Fe–TiN–Al₂O₃ composite powder from ilmenite sand by indigeneouly developed transferred arc plasma reactor

This work discusses the synthesis of Fe–TiN–Al₂O₃ (iron-titanium nitride-alumina) composite powder from the inexpensive raw material ilmenite (FeTiO₃) sand through an alumino-thermic reaction carried out in an indigenously developed transferred arc plasma reactor. Here, the alumino-thermic reaction was studied by varying the processing conditions to synthesize Fe–TiN–Al₂O₃ composite powder without any secondary phases. Initially, the reaction was done in a nitrogen and a combination of argon-nitrogen atmospheres. Second, the input power of the plasma reactor varied from 4 to 7.5 kW. Third, the stoichiometric ratio of aluminum was varied from 2 to 3 moles with ilmenite. From the XRD result, the process done in a combination of argon and nitrogen atmospheres gives more intense Fe, TiN, and Al₂O₃ peaks than the process completely done in an argon atmosphere, and 3 moles of aluminum-added reaction samples give the desired Fe–TiN–Al₂O₃ composite mixture free of other secondary phases. Input power does not affect the formation of the composite mixture. So, the optimum processing conditions for the synthesis of Fe–TiN–Al₂O₃ powder is the gaseous stream of the argon-nitrogen mixture are 4 kW input power and 3 moles of aluminum with ilmenite. FESEM analysis of the plasma-processed slag shows a coarse structure on the surface without any porosity. EDS analysis of the processed sample confirmed Fe, Ti, Al, O, and N as principal elements of the plasma-processed product. By Free Energy Minimization (FEM) plot, the reduction and formation of the Fe–TiN–Al₂O₃ composite are studied.