用ESEM技术研究AP的热分解反应

Thermal Decomposition Reaction of AP by ESEM

采用环境扫描电镜(ESEM)技术对AP颗粒在低温(150～240℃)段进行快速和慢速升温试验,研究了整个形貌的变化历程。结果表明,ESEM能够直观地发现AP颗粒在低温下存在气相反应;在150～170℃,AP颗粒表面开始出现微孔;在170～190℃,微孔数量急剧增加;在190～210℃,表面形成多孔结构;在210℃～240℃,表面出现坍塌及体积皱缩。上述过程不受升温速率的快慢而显著改变,不同升温速率对AP颗粒的影响可能是快速升温容易导致整个颗粒受热不均并在较高的环境温度开始反应,最终在颗粒表面形成裂纹,但它不改变AP的整个反应历程。通过对AP的低温反应历程分析认为:170℃是AP颗粒气相反应的起始点;低温反应的极限失重率达到30%;环境压力可能是影响AP低温分解反应的主要因素。

Envioronmental scanning electron microscope（ESEM）was used to observe the surface topography changes of AP at temperatures ranging from 150℃ to 240℃ at fast and low heating-up.The results showed that gaseous phase reaction on AP can be detected by ESEM.The pores appeared on the surface of AP from 150℃ to 170℃,and the amount of pore increased dramatically from 170℃ to 190℃,then the vesicular structure emerged from 190℃ to 210℃,finally the grain surface collapsed and the volume collapsed at 210-240°.This course didn＇t vary dramatically by the control of the temperature-rise rate,but fast heating-up possibly caused temperature unevenly and the crack appeared,but it didn＇t change the whole course.The gaseous reaction of AP started when the temperature rose up to 170℃.The limit weight loss ratio can reach 30%.Ambient pressure may be the major factor affecting the decomposition reaction of AP at low temperature.