Combustion synthesis of silicon nitride using ultrafine silicon powders
The paper examines the synthesis of α-Si3N4 using ultrafine powders of silicon and inert diluent (α-Si3N4). It is established that the combustion temperature of the mixture based on silicon particles 200 nm in diameter is lower than the silicon melting point (1420°C). The low combustion temperature is obviously attributed to a nanofraction in the silicon powder. The specific surface area of silicon nitride increases with decreasing silicon fraction in the starting mixture. When Si with S sp = 6 m2/g and 12 m2/g is used, the maximum specific surface area of Si3N4 is 6.5 m2/g and 9.6 m2/g, respectively. The content of the low-temperature Si3N4 (alpha phase) modification remains the same in the synthesis product: α /(α + β) ⋅ 100% = 89–93% (∼95 wt.%).
Keywordssilicon nitride synthesis combustion
Unable to display preview. Download preview PDF.
- 5.T. Yamada, “Preparation and evaluation of sinterable silicon nitride powder by imide decomposition method,” Am. Ceram. Soc. Bull., 72, No. 5, 99−106 (1993).Google Scholar
- 6.V. V. Grachev, B. N. Shatalov, V. V. Zakorzhevskii, et al., “Regularities of silicon combustion in nitrogen in SHS reactors,” in: 3rd Int. Symp. Self-Propagating High-Temperature Synthesis (October 23−27, 1995, Wuhan, China), Wuhan (1995).Google Scholar
- 7.V. V. Zakorzhevsky and I. P. Borovinskaya, “Some regularities of α-Si3N4 synthesis in a commercial SHS reactor, Int. J. SHS, 9, No. 2, 171−191 (2000).Google Scholar
- 8.R. A. Andrievskii and I. I. Spivak, Silicon Nitride and Related Materials [in Russian], Metallurgiya, Moscow (1984), p. 136.Google Scholar
- 9.P.-O. Käll, “Quantitative phase analysis of Si3N4-based materials,” Chem. Scr., 28, 439−446 (1988).Google Scholar