Combustion Performance of Porous Silicon-Based Energetic Composites

Abstract

The combustion performance of oxidizer filled porous silicon(PSi) was studied. PSi samples with diameters of 2.54 cm were fabricated by electrochemical etching. The porosity of the samples ranged from 55 to 82%. The samples were cut into 3-5 mm strips and filled with an oxidizer under a vacuum for 5 min to 15 min. The PSi was filled with the oxidizers NaClO4 x 1H2O, Ca(ClO4)2 x 4H2O, sulfur and perfluoropolyether (PFPE). The filled PSi was then burned by igniting the sample with a hot Nichrome TM wire. The experiments were recorded using high speed photography from which burning rates were calculated. The porosity did not appear to have a direct on affect the burning rates for those studied however burning rates did show a strong dependency on quality of the oxidizer loading. The oxidizer loading appeared to be best for the samples with a porosity of 55% that were placed under a vacuum for 15 min. PSi loaded with NaClO4 x 1H2O produced burning rates that ranged from 216-349 cm/s. PSi loaded with Ca(ClO4)2 x 4H2O had burning rates of 154-285 cm/s. A sulfur filled PSi sample burned a rate of 16 to 290 cm/s, and perfluoropolyether loaded PSi burned at a rate of 1.4 cm/s. We believe this is the first time burning rates in PSi have been reported.