摘要
Ammonium perchlorate(AP)includes oxidizing and reducing elements on the same molecule.AP can act as an efficient oxidizer and mono-propellant as well.In this study,AP experienced crystallographic phase change from orthorhombic centrosymmetric to non-centrosymmetric under controlled isothermal heat treatment.XRD diffractograms confirmed this crystallographic phase change.The thermal behaviour of activated AP had been investigated using DSC.Activated AP demonstrated high chemical stability with an increase in endothermic phase transition enthalpy by 170%.The enthalpy of the subsequent two main exothermic decomposition reactions was increased by 250%.Whereas AP demonstrated total decomposition enthalpy of 733 J/g,activated AP showed 2614 J/g.Activated AP can secure self-sustained response at a high rate.Propagation index(combustion enthalpy/ignition temperature)was employed to assess self-sustained reaction propagation.Activated AP demonstrated high propagation index of 8.7 compared with 2.5 for un-activated AP.Primary decomposition kinetic parameters had investigated using Kissinger and KAS methods.Activated AP showed an increase in activation energy by 89%using the Kissinger method;kinetic parameters using the KAS method were in good agreement with the Kissinger method.It can have concluded that AP with novel kinetic decomposition parameters for enhanced safety storage and high combustion characteristics has evolved.
