ABSTRACT
Until the publication of this work, a comprehensive adiabatic assessment of thermitic mixtures or thermites, including nonstoichiometric formulations, was not available. This chapter describes the results of a thermodynamic survey. Fifty-seven reactants’twenty-five metals and thirty-two metal oxides’were assembled into a matrix. Binary combinations were examined computationally with FactSage 7.0 at various stoichiometries, and the resulting adiabatic survey constitutes the basis of this book. Additionally, the chemical and physical characteristics of certain metals, metalloids, and oxides are described. Regarding the survey, the most prominent trends in adiabatic temperature and product phase are identified. Pyrotechnic reactions involving zirconium and hafnium should produce the highest temperatures. Thermites can produce solid, liquid, and gaseous products. The most important distinction is between gas-producing reactions and those that produce only condensed-phase products because reactions that produce gases are more likely to be explosive. It is shown that the maxima of adiabatic equilibrium temperature and gas production profiles may or may not coincide. Thermitic reactions are not constrained by our chemical preconceptions, and realistic simulations can generate complex product distributions or unanticipated products for several reasons. One is that certain suboxides containing metals in unusual oxidation states become increasingly stable at higher temperatures.
