Thermal Behavior and Non-Isothermal Kinetic Studies on Titanium Hydride–Fueled Binary Pyrotechnic Compositions

Abstract

This study describes thermochemical properties and ignition characteristics of pyrotechnic compositions consisting of TiH₂ + KClO₃, TiH₂ + KClO₄, and TiH₂ + Ba(NO₃)₂, where titanium hydride is used as fuel and KClO₃, KClO₄, and Ba(NO₃)₂ act as oxidants. Differential thermal analysis (DTA) and thermogravimetry (TG) techniques have been employed to elucidate the reaction process of these pyrotechnic systems. TG/DTA analysis of pure titanium hydride indicates that this compound decomposes at 535 °C. By replacing KClO₃ with KClO₄ as oxidizer in a titanium hydride–fueled mixture, the sensitivity of the mixture decreases. A TiH₂ + KClO₃ pyrotechnic mixture has a fusion temperature around 358 °C and ignition temperature around 472 °C. A TiH₂ + KClO₄ pyrotechnic system decomposes at 541.5 °C. However, replacing KClO₄ with Ba(NO₃)₂ in this mixture, increases the ignition temperature of the mixture by at least 30 °C to ∼ 570 °C, which is a safe temperature for preventing activation of the mixture by accidental factors such as static electricity. The apparent activation energy (E), ΔG^#, ΔH^#, and ΔS^# of the combustion processes were obtained from the DSC experiments. Thermokinetic data shows that the relative reactivity of these mixtures decrease in the following order: TiH₂ + KClO₃ > TiH₂ + KClO₄ > TiH₂ + Ba(NO₃)₂.

Keywords:

• Ignition
• Kinetic parameter
• Metal hydride fuel
• Oxidant effect
• Pyrotechnic
• Thermal decomposition

Notes

^#The temperatures are peak temperatures at maximum heat flux.

T*is the temperature range associated with a variation sample's mass (decrease).

r* linear regression coefficient.

^a ΔG^#, ΔH^#, and ΔS^#are given at decomposition temperature of most reactive pyrotechnic system (TiH₂ + KClO₃ at 479.3°C).