航天飞行器防热涂层烧蚀行为及机理研究  

The ablation behavior and mechanism of thermal protective coatings used for aerospace vehicles

作　　者：严旭 王洪波[1] 范新中[1] 杨东生 高超 贺晨[2] 王毅飞 YAN Xu;WANG Hongbo;FAN Xinzhong;YANG Dongsheng;GAO Chao;HE Chen;WANG Yifei(China Academy of Launch Vehicle Technology;Aerospace Research Institute of Materials and Processing Technology;The Third Military Representative Office of Air Force Equipment Department in Beijing Area:Beijing 100076,China)

机构地区：[1]中国运载火箭技术研究院,北京100076 [2]航天材料及工艺研究所,北京100076 [3]空装驻北京地区第三军事代表室,北京100076

出　　处：《航天器环境工程》2020年第4期369-376,共8页Spacecraft Environment Engineering

摘　　要：为拓宽航天飞行器防热涂层裂解温域,提高涂层的耐烧蚀性能,文章通过热重–差示扫描量热分析仪(TG-DTG)分析了2种硅橡胶基体的热分解行为,并结合马弗炉烧蚀实验研究铁红、云母、白炭黑等3种功能组元对硅橡胶涂层静态烧蚀性能的影响,通过扫描电镜(SEM)以及红外光谱分析仪(FT-IR)分析烧蚀机理,最后通过马弗炉烧蚀实验及高温燃气流烧蚀实验对2种涂层的烧蚀性能进行考核。结果表明:甲基苯基硅橡胶在220~320℃温域的裂解主要以侧基交联为主;在320~480℃以由羟基引发的主链“回咬”机制为主;在480~630℃则通过链间折叠发生环降解反应。主链“回咬”和链间环降解反应均会导致树脂基体交联密度降低,力学性能下降,产生“粉化”。甲基乙烯基硅橡胶在其裂解温域370~780℃主要发生侧基交联反应,树脂基体交联密度上升,热稳定性提高。白炭黑对于2种硅橡胶基体的热稳定性提升最为显著;铁红、云母等均会在高温下与硅橡胶基体产生共融,减缓硅橡胶基体的高温裂解。In order to broaden the degradation temperature region and improve the ablation properties of spacecraft thermal protective coating,two kinds of typical silicone rubbers are investigated by TG-DTG analysis.Meanwhile,the static ablation properties and the thermal degradation mechanism of the rubbers filled with silica particles,mica,and red iron are studied respectively by the muffle roaster test.The thermal degradation mechanisms are characterized by SEM and FT-IR.Lastly,the ablation properties of the two kinds of silicone rubber-based coatings are tested by muffle roaster test and high temperature gas flow ablation experiment.The results show that for the methyl phenyl silicone rubber at the first thermal pyrolysis stage(220℃to 320℃),the side group cross linking plays an important role;at the second thermal pyrolysis stage(320℃to 480℃),the main chain’s“back biting”is the major reaction;at the third stage(480℃to 630℃),the cyclic degradation occurs by the inter-chain folding.The main chain’s“back biting”weakens the resin's cross linking reaction and lead to mechanical degradation,producing“pulverization”.As for the methyl vinyl silicone rubber,the side group cross linking is essential during the degradation process,which promotes the resin’s cross linking reaction and thus improves the thermal stability.Compared with the other fillers,the silica particles can significantly improve the thermal stability of the two silicone rubbers,while mica and red iron also tend to slow down the thermal degradation rate.

关 键 词：硅橡胶 功能组元 裂解温域 热分解机理 烧蚀性能 高温烧蚀实验 

分 类 号：TQ333.93[化学工程—橡胶工业]