The effect of silicon powder characteristics on the combustion of silicon/Teflon/Viton nanoenergetics

Brandon C Terry, Purdue University

Abstract

Due to its thin passivation layer, potentially good aging characteristics, and ease of surface functionalization nanoscale silicon (nSi) may offer some advantages over nanoaluminum as a reactive fuel in nanoenergetic compositions, particularly with fluorine-based oxidizers. Currently, Si nanopowder can be quite expensive and the quality of commercial powders has been found to vary drastically. As a result limited efforts have focused on the role specific surface area, active content, morphology, and dominant particle size of the powder have on the combustion performance. This work investigates the effect of such characteristics on the combustion of silicon (Si)/polytetrafluoroethylene (Teflon)/FC-2175 (Viton) (SiTV) nanoenergetics. A cost effective combustion synthesis route, salt assisted combustion synthesis, was used to produce several Si powders and these were directly compared to commercial nanoscale Si powders. Reactive mixtures of SiTV were burned at atmospheric conditions and burning rates, combustion temperatures, spectral intensities, and effective plume emissivities were measured. Measured combustion temperatures ranged from 1664 to 2380 K and were limited by Si powder active content. This was found to drive plume emissivity and maximum spectral intensity, which had values ranging from 0.10 to 0.55 for effective plume emissivity and 17.6 to 48.1 kW m -2-sr-1-μm-1 for maximum spectral intensity. Burning rates ranged from 0.7 to 3.4 mm s-1 and were found to be dependent on the dominant particle size of the powder. Powders synthesized with salt assisted combustion resulted in comparable burning rate, plume emissivity and maximum spectral intensity to commercial porous Si powder (Vesta Ceramics).

Degree

M.S.A.A.

Advisors

Groven, Purdue University.

Subject Area

Nanoscience|Energy|Materials science

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