Thermodynamic feasibility of nanoenergetic systems based on metal oxynitrides

Abstract

A comprehensive computational study was conducted to identify and evaluate nano-energetic systems utilizing aluminum (Al) as the fuel and a range of metal oxynitrides as oxidizers. The primary objective was to determine combinations that yield highly exothermic reactions, specifically those that maximize gas generation, adiabatic combustion temperature, and energy release. These parameters are critical for optimizing the performance of energetic materials in applications such as controlled energy delivery, propulsion, and pyrotechnics. By systematically analyzing thermodynamic properties including the heat of formation, enthalpy of reaction, Gibbs free energy, and equilibrium reaction products across a range of Al/oxynitride stoichiometries, the study aimed to pinpoint optimal formulations that balance reactivity, thermal efficiency, and functional versatility. A total of nine Al/oxynitride systems were evaluated to determine the thermodynamic equilibrium concentrations of reaction products, gas output, adiabatic temperature, and energy density by varying the fuel-to-oxidizer ratio. The volumetric and gravimetric energy densities for the most favorable stoichiometries of Al/oxynitride formulations ranged from 0.42 to 10.69 kJ/cm3 and 0.16–2.10 kJ/g, respectively. Gas discharge varied across different metal oxynitride systems, reaching values up to 1.14 l/g depending on the fuel-to-oxidizer ratio. Among the systems investigated, the Al/KGeON formulation exhibited the highest gas generation, producing up to 1.14 l/g of gaseous products. In contrast, the Al/TiNiON formulation displayed the highest energy and volumetric energy density among the systems studied, while distinctly showing no measurable gaseous byproducts, as predicted theoretically and confirmed experimentally. These findings provide critical insights for the strategic design and development of next-generation nano-energetic materials tailored for diverse technological domains and advanced manufacturing.