ABSTRACT
Some of the most basic chemical, physical, and mechanistic properties of thermitic reactions are described. Chemically, these reactions are exothermic reduction–oxidation or “redox” reactions in which an electronegative atom is transferred from one electropositive atom to another electropositive atom. The first practical aluminothermic methods were developed in the late nineteenth century by Hans Goldschmidt. The quintessential thermite is a metastable mixture of powdered aluminum and iron oxides that produces molten iron and alumina when it reacts. However, thermitic science and technology has become so advanced and diverse over the past century that the adjective “thermitic” is arguably more useful now than the noun “thermite.” Numerous examples are presented, with a focus on pyrotechnic compositions and applications. Thermitic systems and thermites are ultimately governed by the laws of thermodynamics. These reactions are thoroughly exothermic and spontaneous. It is shown that the enthalpic characteristics of metal oxides are related to several more fundamental thermochemical properties, and these relationships are explored in detail. Several thermodynamic cycles, based on enthalpy, are presented for this purpose. Basic thermodynamic formalisms are reviewed, and the FactSage thermochemical software and databases are briefly introduced. Clarifications are provided regarding the results of the thermochemical calculations that appear throughout this book.
