Effect of Gas Atmosphere on Carbothermal Reduction and Nitridation of Titanium Dioxide
- 406 Downloads
This article examined the reduction/nitridation of rutile in the He-N2, Ar-N2, and He (Ar)-H2-N2 gas mixtures, as well as pure nitrogen, in the temperature-programmed and isothermal experiments in a fixed-bed reactor. The extents of reduction and nitridation were determined from the off gas composition and LECO analysis. The off-gas composition was monitored using the infrared sensor (CO, CO2, and CH4) and dew point analyzer (H2O). The phase composition of the reduced samples was analyzed using X-ray diffraction (XRD). The temperature and gas composition had a strong effect on the rutile reduction. The reduction was the fastest in the H2-N2 gas mixture, followed by a reduction in nitrogen; the rate of reduction/nitridation in the He-N2 gas mixture was marginally higher than in the Ar-N2 gas. The rate of titania reduction/nitridation in the He (Ar)-H2-N2 gas increased with the replacement of He (Ar) with hydrogen. The article also discusses the mechanisms of reduction/nitridation in different gas atmospheres.
KeywordsTitanium Carbide Carbothermal Reduction Reduction Curve Equilibrium Partial Pressure Final Extent
This research was supported under the Australian Research Council’s Discovery Projects funding scheme (project number DP0771059). Professor Ostrovski is the recipient of an Australian Research Council Professorial Fellowship. Sheikh Abdul Rezan was the recipient of a scholarship from the Universiti Sains Malaysia.
- 5.M.A.R. Dewan, G. Zhang, and O. Ostrovski: Metall. Mater. Trans. B, 2010, vol. 41B, pp. 182–92.Google Scholar
- 7.G. Zhang and O. Ostrovski: Can. Metall. Q., 2001, vol. 40, pp. 489–98.Google Scholar
- 8.G. Zhang and O. Ostrovski: Can. Metall. Q., 2001, vol. 40, pp. 317–26.Google Scholar
- 9.G. Zhang and O. Ostrovski: Metall. Mater. Trans. B, 2001, vol. 32B, pp. 465–73.Google Scholar
- 11.S.A. Rezan, G. Zhang, and O. Ostrovski: J. Am. Ceram. Soc., 2011, DOI: 10.1111/j.1551-2916.2011.04703.x.
- 14.M.W. Chase: NIST-JANAF Thermochemical Tables, 4th ed., American Chemistry Society, Washington, DC, 1998.Google Scholar