Synthesis of nano perovskite rare earth metal oxide LaxFeyOz particles and their catalysis effects on the thermal decomposition of ammonium perchlorate (AP)

Abstract

Aimed at the relatively little research on the thermal decomposition performance of AP with nano perovskite rare earth metal oxide catalysts, the influence of different calcination temperatures on the catalysis behavior of nano La_xFe_yO_z on AP decomposition and ignition and combustion performance of AP/Al composite fuels was investigated. La_xFe_yO_z perovskite-type nano-oxide particles with different microstructures prepared with the sol–gel methodand calcined at 400 °C, 500 °C, 600 °C, and 700 °C were designated as La_xFe_yO_z-1, La_xFe_yO_z-2, La_xFe_yO_z-3, and La_xFe_yO_z-4 respectively. The structural characteristics, catalytic behavior on the thermal decomposition of ammonium perchlorate (AP), and the effects of adding La_xFe_yO_z-1 perovskite-type nano-oxides on the ignition and combustion of AP + Al composite fuel were investigated for its optimized catalytic performance of AP. The results show that under the catalysis of LaFeO₃ particles produced at varying calcination temperatures, the peak temperatures for the exothermic decomposition of AP decreased by 109.50 °C, 86.29 °C, 82.92 °C, and 80.82 °C, while the total exothermic heat output increased by 375.77 J g⁻¹, 314.65 J g⁻¹, 459.61 J g⁻¹, and 386.83 J g⁻¹ respectively. The maximum decomposition rates occurred at 343.86 °C, 364.78 °C, 370.26 °C, and 372.88 °C, corresponding to rates of 37% min⁻¹, 26% min⁻¹, 22% min⁻¹, and 28% min⁻¹. As the content of the nano La_xFe_yO_z-1 particles in the La_xFe_yO_z-1/AP/Al composite fuel increased from 0.5 wt% to 1 wt% and then 2 wt%, the ignition delay times decreased sequentially to 103 ms, 90 ms, and 80 ms, shorter than the AP/Al composite fuel by 29 ms, 42 ms, and 52 ms, representing reductions of 21.9%, 31.8%, and 39.3%. When the content of the nano La_xFe_yO_z-1 particles was 0.5%, the flame structure during the steady burning stage exhibited a certain degree of spark ejection. However, at the content of 1.0% La_xFe_yO_z-1 particles, the flame area in the steady burning stage increased relative to the 0.5% addition, and the intensity of spark ejection strengthened. No significant changes in flame area or spark ejection intensity were observed when the content was increased to 2.0%.