Fabrication of nano-TiN powder by pyrolysis conversion of TiO/sub 2/ in a fluidized bed furnace

Nano-structure TiN powders were prepared by using anatase-TiO/sub 2/ and graphite mixtures as the precursor. Prior to thermal conversion, the mixture of TiO/sub 2/ 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 N/sub 2/ into a low pressure circulated fluidized-bed reactor which was previously evacuated to the pressure around 10/sup -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 TiO/sub 2/ + graphite had not undergone a severe milling.