Thermoanalytical Investigation of Some Binary Pyrotechnic Mixtures of Ammonium Azide as Chemical Gas Generating Systems

Abstract

The conventional NaN3/oxidants gas generator pyrotechnic mixtures suffer from leaving undesirable solid residues. The presented investigation aimed to overcome this problem through mixing of NH4N3 particles with some metallic components, and to introduce some new gas generator pyrotechnic mixtures. In this work, volatile ammonium azide particles were initially stabilized via microencapsulation technique, and blended with Zr, Ti, ZrH2, and TiH2 powders to produce different gas generation mixtures. Thermal properties and kinetic parameters of these pyrotechnic mixtures were investigated by using thermal analysis (TG/DTA and DSC) techniques. The apparent activation energy (E), ΔG#, ΔH#, ΔS#, and critical ignition temperature (Tb) of the ignition processes of the mixtures were obtained from the DSC experiments. Among the investigated mixtures, NH4N3/ZrH2 composition was found to show desirable efficiency, and also it can be considered as a safe pyrotechnic composition for gas generation property, due to its moderate ignition temperature.

Development of green‐colour‐emitting pyrotechnics as a core for 3D temperature imaging sensors inside coal boilers

“…[ 32 ] However, when mixed with fuel and other organic sources, they decompose at lower temperatures. This has been seen previously by other researchers, [ 33,34 ] in which Sn + KClO 4 and Sn + Ba(NO 3 ) 2 mixtures decomposed at lower temperatures. Similarly, in another study, [ 44 ] when Ba(NO 3 ) 2 and KClO 4 were combined with MgAl (magnalium), the mixture decomposed at much lower temperatures than the individual pure components.…”

“…These differences are clearly due to the nature of oxidation for these metals, as discussed in Figure S3 in Appendix S1. This has been observed in the case of individual mixtures of Sn/oxidant [ 34 ] and Mg/oxidant, [ 50 ] where Sn shows a flat curve whereas Mg shows a rapid gain. Cobalt has one noticeable drop at approximately 420°C, which is earlier than the drop at 500°C.…”

“…[ 32 ] Recent studies have also used ‘Sn’ as a metallic fuel. [ 33,34 ] Additionally, to the best of our knowledge, no study using ‘Co’ as a metallic fuel has been reported. As metals are a key component of the colour producing pyrotechnic mixture, part of this study focused on the thermal investigation of a green‐coloured pyrotechnic system utilizing three different metals: Mg, Co, and Sn, and their effects on green light emission for BaN‐ and BC‐based compositions.…”