Effect of oxidant coating boron particle on the ignition and combustion characteristics of boron-based propellant

The boron-based propellant samples were prepared through coating boron particles with a recrystallization method selecting ammonium perchlorate(AP), ammonium nitrate(AN), nitroguanidine(NQ) and octogen(HMX) as four kinds of oxidants. The effect of different oxidant coating on the ignition and combustion characteristics of boron-based propellant was studied by using TG-DSC and laser ignition test system. The mechanical mixing sample was set as control group. Results show that AP coating can induce low-temperature deflagration of the sample, so as to promote the low-temperature oxidation of boron particles. It helps to effectively shorten the ignition delay time of the sample to 330 ms. By comparing with the mechanical mixing sample, the recrystallization method was found to be the main cause of low-temperature deflagration of the sample. The sample coated by AN has a lower initial reaction temperature of 327.6℃. However, its whole exothermic properties are poor, the average combustion temperature is only 642.8℃. The coating of NQ and HMX can effectively improve the combustion strength of B-based propellants, shorten the combustion time. Among them, NQ can help to improve the maximum combustion intensity. HMX is more conducive to the upgrade of the whole combustion intensity. The coating of HMX makes the combustion time of B-based propellant shorten to 2750 ms, the average combustion temperature reaches 845.5℃ and the heat release is raised to 9968 J·g-1. © 2016, Editorial Board of Chinese Chinese Journal of Energetic Materials. All right reserved.