Vapour-phase reduction and the synthesis of boron-based ceramic phases
- 150 Downloads
Thermodynamic calculations have been performed to establish the partial pressure relationships between the gaseous species BO and CO at an isotherm during the reduction-nitridation of boric anhydride. This relationship enables us to establish the condition for the formation of boron nitride ceramic phase by selecting a suitable nitriding atmosphere. Relevant Gibbs free-energy equations have also been considered for establishing the phase equilibrium relationships over a wide range of temperature in the B-C-N-O system. The importance of BO gas formation and its subsequent reduction to BN is also discussed.
KeywordsBoron Nitride Partial Pressure Anhydride Phase Equilibrium
Unable to display preview. Download preview PDF.
- 2.A. Meller, in “Gmelin Handbook of Inorganic Chemistry”, 8th Edn, edited by K. Buschbeck (Springer, 1988) pp. 3–89Google Scholar
- 3.K. A. Schwetz and A. Lipp, in “Ullmann's Encyclopedia of Industrial Chemistry”, Fifth Completely Revised Edn, Vol. A4, edited by W. Gerhartz (VCH, Munich, 1985) p. 295.Google Scholar
- 4.D. Segal, “Chemical Synthesis of Advanced Ceramic Materials”, 1st Edn (Cambridge University Press, Cambridge, 1991) p. 89.Google Scholar
- 5.E. T. Turkdogan, “Physical Chemistry of High Temperature Technology” (Academic Press, 1980) pp. 5–24.Google Scholar
- 6.G. A. Cochran, C. L. Conner, G. A. Eisman, A. W. Weimer, D. F. Carroll, S. D. Dunmead and C. J. Hwang, in “Silicon Nitide 93”, Proceedings of the International Conference on Silicon Nitride-Based Ceramics, Sttutgart, 4–6 October 1993, edited by M. J. Hoffmann, P. F. Becker and G. Petzow (Trans Tech Publications, Brookfield, Vermont) pp. 3–8.Google Scholar
- 7.O. Knacke, O. Kubaschewski and K. Hesselmann, “Thermochemical Properties of Inorganic Substances I”, 2nd Edn (Springer, Berlin, 1991) p. 147.Google Scholar