Combustion synthesis of silicon nanopowders

Spark plasma sintering of SiC powders produced by different combustion synthesis routes

“…The size of the SiC grains formed in the second stage of the interaction does not have a direct relation to the size of the initial precursors because the combustion temperature is above the melting point of SiO 2 , and they recrystallize from the melt. However, the size of SiC grains should correlate with the scale of heterogeneity of the formed Si matrix, which, as was shown previously, 17 is on the order of 100-200 nm. The only complexity of the approach is the necessity of the leaching stage for the elimination of the undesired MgO phase.…”

“…The measured maximum combustion temperature in SiO 2 + 2Mg system is above 2000 K, and only 200 K less than that for the SiO 2 + 2Mg + C system. 17 Thus the reduction reaction producing silicon brings the formed Si-C system to a high temperature (>2000 K) at which the second synthesis-type reaction occurs. The microstructure of formed SiC particles suggests that this stage involves the dissolution of carbon in the silicon melt, followed by its rapid crystallization.…”

Porous Silicon Formation by Porous Silica Reduction

“…The latter study used compacted feedstock cylinders of dimensions 1-4 cm diameter and 2.5-5 cm length in a combustion furnace. Calculations suggest the batch sizes in the Yermekova et al (2010) study were thus as high as 85 g. Combustion synthesis could be an attractive process for macroporous silicon with surface areas of 5-100 m 2 /g but is unlikely to have sufficient thermal control to achieve tunable mesoporous nanostructures.…”

“…Despite the inexpensive feedstocks used (silica and magnesium), the batch sizes reported in the vast majority of studies (Bao et al 2007;Richman et al 2008;Hai et al 2009;Ibisate et al 2009;Won et al 2009;Yu et al 2010;Zhu et al 2010Chen et al 2011aChen et al , b, 2012aChen et al , b, 2013aGallego-Gomez et al 2011;Gao et al 2011;Guo et al 2011;Jia et al 2011;Lu et al 2011;Pallavidino et al 2011;Won et al 2011;Zhang and Huang 2011;Fang et al 2012;Shen et al 2012Shen et al , 2013Tao et al 2012a, b;Wang et al 2012;Yoo et al 2012;Huachao et al 2013;Jung et al 2013;Du et al 2013;Hong et al 2013;Jiang et al 2013;Lee et al 2013;Liu et al 2013;Luo et al 2013;Ma et al 2013;Meekins et al 2013;Wen et al 2013;Xing et al 2013a, b) are in the mg to gram range. Two exceptions are from the studies of Batchelor et al (2012) where salt was used as a thermal moderator to keep reactant powder temperature as low as possible and, at the other extreme, Yermekova et al (2010) where thermal runaway was exploited for combustion synthesis. The former study had a continuous flow of 30 g tray batches with high salt content in a belt furnace setup.…”

The Effect of Silicon Powder Characteristics on the Combustion of Silicon/Teflon/Viton Nanoenergetics

“…All powders utilized in this work were as-received, without any purification treatments prior to the formation of reactive mixtures. All constituents were thoroughly mixed in desired ratios (see Equation (1)) in an ethanol bath (2 : 1 wt.-%, ethanol:powder mixture ratio) with zirconium oxide (ZrO 2 ) milling balls (2 : 1 wt.-%, ball:powder mixture ratio) for 6 h, followed by drying in a temperature controlled oven at 353 K for 12 h. Combustion synthesis and subsequent hydrometallurgical treatment was then performed on the reactive powders following the procedure outlined by Yermekova et al [32].…”