Carbothermal Reduction and Nitridation of Titanium Dioxide in a H^sub 2^-N^sub 2^ Gas Mixture

This article examines carbothermal reduction/nitridation of rutile in a ... gas mixture in the temperature-programmed and isothermal experiments in a fixed-bed reactor. The aim of this investigation was to establish the reduction/nitridation sequence, the reaction degree, and the rate of synthesis of titanium oxycarbonitride under different experimental conditions. The off-gas composition was monitored using an infrared sensor (CO, ..., and ...) and a dew point analyzer (...). Extents of reduction and nitridation were determined from the off-gas composition and LECO analysis. Phase composition of reduced samples was analyzed using powder X-ray diffraction (XRD). Rate and extent of conversion of titanium oxides to titanium oxycarbonitride increased with increasing temperature. The conversion of titania into titanium oxycarbonitride at 1150...C was completed in 180 min; the conversion time decreased to 30 min at 1300...C. Increasing temperature resulted in formation of titanium oxycarbonitride with higher TiC content. Porosity had a minor effect on the reduction/nitridation of titania with the tendency to increase the reduction rate with increasing porosity. Reduction/nitridation of titania at 1150...C followed the sequence: ... (ProQuest: ... denotes formulae/symbols omitted.)