Effect of aluminum particle size on thermal decomposition of AP

The effect of aluminum particle sizes of 10.7 μm, 2.6 μm and 40 nm on the thermal decomposition of ammonium perchlorate(AP) was investigated by thermogravimetry-Differential Scanning Calorimetry(TG-DSC). The addition of Al resulted in an increase in the temperature of the low-temperature exothermic peak and a decrease in the temperature of the high-temperature exothermic peak of AP. These changes were more pronounced with an increase in the Al content and a decrease in the aluminum particle size. The processing of non-isothermal data at various heating rates without and with 40%(mass fraction) Al was performed by Netzsch thermokinetics. The dependence of the activation energy calculated by Friedman's isoconversional method on the conversion degree indicated the decomposition process can be divided into three steps for AP and all the AP/Al mixtures determined by multivariate non-linear regression. They are C1/D1/D1(C1: 1st order autocatalysis; D1: one-dimension diffusion reaction) for neat AP, and change to C1/D1/D3(D3: three-dimension Jander diffusion reaction), C1/D1/D4(D4: three-dimension Ginst-Broun diffusion reaction) and C1/D1/F2(F2: 2nd order reaction) after addition of 10.7 μm, 2.6 μm and 40 nm into AP, respectively.