Pyrolysis mechanisms of commonly used oxidizers on the 5-amino-1H-tetrazole

As a novel energetic material, 5-Amino-1H-tetrazole (5AT) has a history of proposed applications in the fields of airbags, rocket engines, and new propellants. However, the application of 5AT is limited for its poor combustion stability. Identification of the thermal behaviour and pyrolysis mechanism of 5AT could provide guidance on the control of combustion behaviour, which can be effectively improved by adding oxidizers. In this paper, five kinds of oxidizers (Ammonium perchlorate (AP), Sodium perchlorate (NaClO₄), Ammonium nitrate (AN), Manganese oxide (MnO₂), and Chromic oxide (Cr₂O₃)) are mixed with 5AT for investigating the catalytic effects of multi-type oxidizers on 5AT. Thermal behaviour is analysed by the TG-DSC test and the thermal activation energy is evaluated by Kissinger and Ozawa methods. Moreover, TG-FTIR and TG-MS analyses are used to infer the pyrolysis gas products of 5AT/oxidant. The experimental results indicate that the 5AT-AN has the lowest activation energy, and the degradation process was simplified into one step. The addition of AP, NaClO₄, and MnO₂ can promote the pyrolysis process of 5AT due to the redox reaction between melamine and the decomposition products of oxidizers, while the catalytic effect of Cr₂O₃ mainly occurs above 400 °C without the occurrence of oxidation. The catalytic mechanism of Cr₂O₃ mainly performs on the polyaddition and the ring-opening reaction of N-containing heterocycles. The findings of this work may offer valuable direction for understanding, designing, and using 5AT-based propellants.