A parametric study of reactive wave propagation in nanoporous silicon energetic composites

This paper presents a comprehensive study aimed at understanding various parameters that affect the reactive wave propagation speed (n), and thus, the energy release rate. N- and P- doped silicon substrates were etched to prepare nPS with different pore structures, which was characterized by gravimetric, microscopic, and gas adsorption techniques. Energetic composites with varying equivalence ratios (φ) were prepared by impregnating nPS samples with perchlorate salts, which were studied by high speed videography and spectroscopic temperature measurements. Samples forming random micro-crack patterns always exhibited n in the order of 300 -400 m/s, whereas samples without such microstructure exhibited n between 2 -11 m/s for a wide range of φ. Further, controlled hierarchical structures with micro and nanoscale features (matrix of pillars and microchannels) were fabricated to tune n over two orders of magnitude (from 2 m/s to 500 m/s) by changing the burn mode from conductive burning to convective burning.