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Carbothermal Reduction and Nitridation of Titanium Dioxide in a H 2 –N 2 Gas Mixture
Author(s) -
Rezan Sheikh A.,
Zhang Guangqing,
Ostrovski Oleg
Publication year - 2011
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2011.04703.x
Subject(s) - rutile , titanium , carbothermic reaction , materials science , titanium dioxide , nitriding , anatase , isothermal process , analytical chemistry (journal) , porosity , mineralogy , metallurgy , chemical engineering , chemistry , catalysis , nanotechnology , photocatalysis , composite material , layer (electronics) , chromatography , carbide , biochemistry , physics , engineering , thermodynamics
This article examines carbothermal reduction/nitridation of rutile in a H 2 –N 2 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 , CO 2 , and CH 4 ) and a dew point analyzer ( H 2 O ). 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: TiO 2 →Ti 5 O 9 →Ti 4 O 7 →Ti 3 O 5 →TiO x C y N z .