Reactivity of The Ternary Pyrotechnic System Red Lead - Silicon - Ferric Oxide

Abstract

The reactivity of the ternary system of red lead, silicon and ferric oxide has been studied in comparison with the binary system red lead-silicon. Results from Differential Scanning Calorimetry (DSC) in nitrogen environment and Differential Thermal Analysis (DTA) in air have been supplemented with hot stage microscopy and combustion rate studies at about 30 atmospheres pressure. The ternary mixtures show three characteristic exotherms whose relative exothermicities vary with composition. DTA showed an unusual feature of a strong single exotherm at a certain critical mass which also varies with the composition. The critical mass could be reproduced within +-1.0 mg. Hot stage microscopy of the pyrotechnic samples revealed strong surface mobility during the reaction leading to the formation of a sintered product. Self sustained combustion rates of the samples show an inhibiting effect by ferric oxide.