三维有序多孔纳米铝热薄膜结构设计及其燃烧耦合匹配机制

Nanothermite has attracted the concerns from many researchers for its improved performances such as high energy density, high energy releasing rate and short ignition delay time. The researchers have laid their focus on the aspect of integrating the nanothermite membrane into MEMS devices to meet the demands of the energy and diversity of function on MEMS devices. The technique of depositing metallic oxides and aluminum alternately onto the substrates was widely employed to improve the energy output of MEMS devices, however the methods adopted by researchers are costly, time-consuming and difficult to scale up, limiting the nanothermite’s application on MEMS devices. In this study, the three-dimensionally ordered macroporous structured nanothemite film will be obtained through depositing aluminum into the three-dimension ordered macroporous metallic oxides film which will be fabricated by the template synthesis that shows good compatibility with MEMS technology. SEM, TEM and XRD will be applied to study the laws of different treatmentconditions on the pore diameter of metallic oxides and thickness of aluminum. Furthermore, the performances of nanothermite film such as burning rate, pressure, temperature and heat output will be characterized by High-speed Camera, Pressure Measurement of micro-detonation, Double Line of Atomic Emission Spectroscopy and DSC as well. To reveal the coupling mechanism of nanothemite film between the structure and combustion performance, variation laws of the combustion performance of nanothermite film with its reactionkinetics and interface will be elucidated using density functional theory. Hopefully, the present project will definitely provide significant data and scientific strategies for application of nanothermite film.

作为含能材料研究前沿的纳米铝热剂具有能量释放速率快、点火延期时间短等优点，将纳米铝热剂以薄膜的形式集成到MEMS器件有助于解决该器件面临的能量需求高、多功能化等难题。目前金属氧化物和铝交替沉积的工艺费时费力、价格昂贵，限制了纳米铝热剂在MEMS上的应用。本课题拟采用能与MEMS工艺兼容的模板法制备出微米厚度的三维有序多孔纳米金属氧化物，再通过气相沉积Al得到纳米铝热薄膜。采用SEM、TEM、XRD等方法研究不同处理条件对多孔纳米金属氧化物壁厚、Al的装填厚度等的影响规律，利用高速摄影、微型爆轰压力测量仪、双谱线测温、DSC等手段研究金属氧化物种类、Al与氧化物的结合程度对纳米铝热薄膜燃速、压力、温度、放热量的影响规律，采用密度泛函理论从分子尺度阐释反应动力、反应界面等因素对纳米铝热薄膜燃烧性能的影响，揭示纳米铝热薄膜结构与燃烧性能的耦合机制，为纳米铝热薄膜的应用提供可靠数据和理论指导。

MEMS含能器件的发展对含能材料提出高能输出、低能刺激以及与MEMS工艺兼容等高要求，传统含能材料受其制备工艺和装药方式的限制，已经不能满足该发展要求。纳米铝热剂具有能量密度高、能量释放速率快、点火延期时间短等优点，将纳米铝热剂以薄膜形式集成在MEMS器件上有助于解决其面临的能量需求高、多功能化等难题。. 本项目采用聚苯乙烯球模板法结合磁控溅射镀铝的方式制备出多种三维有序多孔纳米铝热薄膜（Fe2O3/Al，CuO/Al和Co3O4/Al）。通过控制纳米铝层的厚度对铝热薄膜的组分、形貌以及放热性能进行有效调控。通过研究不同种类金属氧化物、不同铝和氧化物接触程度对纳米铝热薄膜的燃烧反应性能差异，包括放热量、活化能以及燃烧压力等，获得纳米铝热薄膜的燃烧反应性能的影响规律。镀铝厚度为200nm时，三维多孔铝热薄膜的燃烧反应性能达到最佳。其中三维多孔铝热薄膜放热量大小依次为Co3O4/Al＞CuO/Al＞Fe2O3/Al，反应活化能大小依次为Fe2O3/Al＞CuO/Al＞Co3O4/Al，燃烧压力大小依次为CuO/Al＞Fe2O3/Al，表明Co3O4/Al在反应过程中放热量最大，活化能最小；CuO/Al的产气量最大。另外，磁控溅射使三维多孔金属氧化物骨架和Al在纳米尺度上紧密接触，组分间传质传热的阻力小，其反应活化能明显小于自组装制备的半紧密接触的纳米铝热剂；而自组装制备的纳米铝热剂由于引入含碳的表面活性剂能使其产生更大的燃烧压力。. 采用密度泛函理论从分子尺度阐释反应温度、反应界面等因素对纳米铝热薄膜燃烧性能的影响规律。运用第一性原理分子动力学，从不同温度下纳米铝热薄膜反应结构的演变、氧原子的迁移、电子结构等方面研究纳米铝热剂的反应过程， 获得纳米铝热薄膜的燃烧反应机制，为纳米铝热薄膜的应用提供可靠数据和理论指导。