Combustion of some zinc-fuelled binary pyrotechnic systems

Abstract

Combustion studies of several binary pyrotechnic systems using zinc as fuel and one of the oxidants: PbO 2, Pb 3O 4, PbO, BaO 2, SrO 2 or KMnO 4, are reported. Combustion was very sensitive to compaction, and only mixtures of Zn PbO 2 , Zn Pb 3 O 4 and Zn KMnO 4 sustained combustion when compacted. In all of the systems studied, the temperatures measured during passage of the combustion front past an imbedded thermocouple rapidly rose above the melting point of zinc. Burning rates were recorded for the Zn PbO 2 system compacted under 50 MPa, and the Zn KMnO 4 system under 50, 100 and 150 MPa. Thermochemical and kinetic data were determined where possible. Combustion mechanisms are suggested, involving condensed phase, diffusion-controlled reactions and gas-phase reactions occurring in parallel. Analysis of residues shows that ZnO is the major product in the Zn PbO 2 and Zn Pb 3 O 4 systems, and that mixed zinc oxides are possibly the major products of the Zn KMnO 4 , Zn BaO 2 and Zn SrO 2 systems.