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

ABSTRACT

Binary metal oxide (Co–M oxide, where M = Fe or Zr) particles with various elemental compositions, Co _x Fe _y O _z and Co _x Zr _y O _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 _x Fe _y O _z particles are relative irregular, with particle sizes ranging from 80 to 200 nm, and exhibit significant aggregation. Co _x Fe _y O _z ‐1, Co _x Fe _y O _z ‐2, and Co _x Fe _y O _z ‐3 particles predominantly consist of the Co _3‐x Fe _x O ₄ , while Co _x Fe _y O _z ‐4 and Co _x Fe _y O _z ‐5 are mainly composed of CoFe ₂ O ₄ , with a minor amount of Fe ₂ O ₃ present in Co _x Fe _y O _z ‐5. Co:Fe atomic ratio of 4:1, Co _3‐x Fe _x O ₄ 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 _x Zr _y O _z , compositions with Co:Zr atomic ratios of 4:1, 2:1, 1:1, and 1:2 contained particles of two distinct sizes: small ZrO ₂ and large Co ₃ O ₄ 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 ZrO ₂ (10 nm) at a Co:Zr ratio of 1:4. The Co _x Zr _y O _z ‐2 mixture, with a Co:Zr ratio of 2:1 consisting of Co ₃ O ₄ (60–100 nm) and ZrO ₂ (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.