Effect of Chemistry on the Performance of Calcium Disilicide Primers

Abstract

ABSTRACTRotary atomization was used to synthesize spheres of CaSi2-based compositions in order to understand issues relative to primer performance for military applications. Elemental silicon and calcium were used to synthesize the line compound CaSi2or the eutectic composition between CaSi2and Si. Fe was added to form FeSi2as a secondary phase in selected compositions. Rietveld analysis showed that CaSi2polytypes in the synthesized materials consisted primarily of 6R, with less 3R and some hexagonal material. Synthesized materials had low surface areas (≈0.1 m2/g), but short milling times increased the surface area by an order of magnitude. Peak pressures, pressure rise time, and ignition voltage showed no significant differences between experimentally prepared samples and existing commercial samples. Stoichiometric CaSi2performed as well as CaSi2-Si or CaSi2-FeSi2-Si mixtures. The military specification for calcium disilicide should be changed to reflect the broad chemistry which can be used for primer performance.