The Different Catalysis of Co–M Oxide Nanoparticles in Steering the Thermal Decomposition of Ammonium Perchlorate

Binary metal oxide (Co–M oxide, where M = Fe or Zr) particles with various elemental compositions, Co_xFe_yO_z and Co_xZr_yO_z, were synthesized via liquid-phase precipitation followed by high-temperature calcination. Effect of alloy element content on the microstructure, crystal structure, and catalytic performance of ammonium perchlorate (AP) were investigated and laser ignition experiments on the effect of Co-based binary oxides on AP + Al composite fuel ignition and combustion were conducted. The results show that prepared Co_xFe_yO_z particles are relative irregular, with particle sizes ranging from 80 to 200 nm, and exhibit significant aggregation. Co_xFe_yO_z-1, Co_xFe_yO_z-2, and Co_xFe_yO_z-3 particles predominantly consist of the Co_3-xFe_xO₄, while Co_xFe_yO_z-4 and Co_xFe_yO_z-5 are mainly composed of CoFe₂O₄, with a minor amount of Fe₂O₃ present in Co_xFe_yO_z-5. Co:Fe atomic ratio of 4:1, Co_3-xFe_xO₄ as catalyst reduced the temperature of the exothermic peak for AP decomposition from 453.02°C to 345.95°C with the total exothermic heat increasing from 575.48 J/g to 1271.65 J/g. The ignition delay time for the mixed fuel was 109 ms. For Co_xZr_yO_z, compositions with Co:Zr atomic ratios of 4:1, 2:1, 1:1, and 1:2 contained particles of two distinct sizes: small ZrO₂ and large Co₃O₄ particles. At a 4:1 ratio, the powder predominantly consisted of larger particles (100–150 nm), decreasing in size and prevalence as the Zr ratio increased, with particles mainly shifting to small ZrO₂ (10 nm) at a Co:Zr ratio of 1:4. The Co_xZr_yO_z-2 mixture, with a Co:Zr ratio of 2:1 consisting of Co₃O₄ (60–100 nm) and ZrO₂ (10–15 nm) reduced the AP decomposition peak temperature from 453.02°C to 311.16°C with a total exothermic heat of 995.35 J/g, and a composite fuel ignition delay time of 80 ms.