Fabrication of nano-TiN powder by pyrolysis conversion of TiO2 in a fluidized bed furnace

Nano-structure TiN powders were prepared by using anatase-TiO₂ and graphite mixtures as the precursor. Prior to thermal conversion, the mixture of TiO₂ and graphite was milled in a high energy attritor to enhance the validity of carbothermic reduction. The nano-TiN powders were thermal converted by introducing N₂ into a low pressure circulated fluidized-bed reactor which was previously evacuated to the pressure around 10^-1 torr. The formation of TiN compound is greatly enhanced by high-energy milling due to the reduced crystallite size, large grain boundary area, presence of amorphous phases and the increased defect concentration in the powder reactants given by the high-energy milling. The experiment results evidenced that the carbothermic reduction could not occur if the powder mixture of TiO₂ + graphite had not undergone a severe milling.