Abstract: In order to investigate the ablation characteristics and mechanism of EPDM insulation material in high temperature alumina droplet deposition condition，based on the lab-scale experimental device，the ablation experiment was performed. SEM and XRD were used to analyze the surface morphology and chemical composition of the charring layer after ablation experiment，the main reaction mechanism of the alumina droplet and charring layer in Solid Rocket Motor (SRM) operating condition was discussed，then the chemical reaction equation under deposition condition was determined. The results shows that: (1) the EPDM insulation material charring layer section presents porous structure of “tight/loose” under the condition of alumina droplet deposition. (2) The seven-step thermo-chemical reaction equation of alumina and charring layer in high temperature and high pressure environment of SRM was deduced and established. (3) Thermodynamic analysis shows that under the SRM operating condition，the reaction of alumina and charring layer first formed Al4C3，with the temperature increased，Al elemental and carbon-oxygen-aluminum compound Al2OC were formed and then released the gas of CO.

Key words: Solid rocket motor(SRM)；Insulation material；Deposition；Ablation；Experimental device

摘要： 为了研究三元乙丙绝热材料在高温氧化铝液滴沉积条件下的烧蚀特性，基于模拟沉积实验装置，开展了烧蚀实验研究。利用SEM与XRD等分析了烧蚀后炭化层断面形貌特征和化学组分分布，探讨了火箭发动机工作环境中氧化铝液滴与炭化层间热化学烧蚀的主要反应机理，确定了沉积条件下的化学反应方程式。研究结果表明:(1)高温氧化铝沉积条件下，三元乙丙绝热材料材料炭化层断面呈现“致密/疏松”的多孔结构；(2)推导并建立了固体火箭发动机高温高压环境中氧化铝与炭化层的七步热化学反应方程；(3)利用热力学软件分析可知，发动机工作条件下氧化铝与炭化层反应首先生成Al4C3，随着温度的升高继而生成Al单质与碳-氧-铝化合物Al2OC并释放出还原性CO气体。

关键词: 固体火箭发动机；绝热层；沉积；烧蚀；实验装置