Density pyrotechnic fuels

Chavez and Hiskey continued their research on 1,2,4,5-tetrazine-based explosives and synthesized a number of derivatives which are considered interesting as propellant or smoke-free pyrotechnic ingredients because of their low carbon content, high heat of formation and a density of-1.61 g cm4. One such compound is 3,6-dihydrazino-l,2,4,5-tetrazine which appears to be an important energetic fuel [275, 276]. 

Some of the important properties which are considered when choosing the ingredients for pyrotechnic formulations are density, hygroscopicity, melting and boiling points and decomposition temperatures, oxygen content of oxidizers, thermal conductivity of fuels and containers, nature of combustion products and toxicity etc. 

In both explosives and propellants the materials are relatively non-porous. The binders and plasticizers used effectively fill the pore spaces. Pyrotechnics are porous and the heat transfer related to the hot gas permeation into the reactant material mixture becomes important. In many pyrotechnics no binders or plasticizers are used. The explosives and propellants have burning (or detonation) rates that depend on density, temperature, and pressure. However, the burning rates of pyrotechnics are, in addition, affected by porosity, particle sizes, purity, homogeneity (degree of mixing), and stoichiometry (fuel or oxidizer ratio). 

Depicted uranium is used extensiveiy in pyrotechnics which have armor piercing capabiiities. Depicted uranium deficient in the more radioactive isotope U235, is the waste product of the uranium enrichment process. The depicted uranium is formed into projectiles that can penetrate armor because of their high density and mechanical properties. The impact of the projectile causes the uranium to form many pyrophoric fragments which can ignite fuel and munition items. 

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