Al/Ni纳米多层复合膜材料在电爆炸中的基础研究

Al/Ni reactive multilayer foils, normally prepared by magnetron sputtering, are a kind of new nano energetic materials of metastable crystal form that comprising alternant nano-scale layers of Al and Ni. They can also generate significant heat and produce intermetallic compound by self-propagating reaction between layers stimulated by heat, therefore they are also a new kind of energy storage material..In order to use the reactivity and energy storage property of the materials, Al/Ni reactive multilayer foils with a stored energy no less than 85% of the theoretical value and AlNi intermetallic compound foils are going to be prepared by magnetron sputtering in this project. Explosion experiments of the two materials under large current stimulation will be carried out..Reaction mechanism of Al/Ni multilayers explosion will be studied by analyzing their mechanical power exportation, the explosive products, spectroscopy datas and voltage-time curve of explosion process. Base on the above mentioned analyses, reaction mechanism of multilayers explosion under large current stimulus will be consummated based on the existing theory of a single metal foil explosion through comparing with single nano metal foil on the explosion curve and spectroscopy datas. The reaction mechanism of multilayers explosion will therefore provide the necessary theory for the design, preparation and application of special superfine nano-intermetallic powder compound materials.

采用磁控溅射镀膜方法制备的Al/Ni纳米复合膜是一种纳米级亚层结构的新型亚稳态晶形含能材料，在加热及点火条件下能发生自蔓延燃烧反应并放出大量热量同时生成金属间化合物，也是一种新型的储能材料。本项目利用这种纳米晶复合膜材料自身具有反应性及储能的特点，采用磁控溅射精确控制技术制备放热量不低于理论放热量的85%的Al/Ni纳米多层复合膜材料，同时制备AlNi金属间化合物膜材料，在强电激励下分别使其发生电爆炸并研究其做功能力，对爆炸后的产物进行成分分析，采用同步条纹相机按时间分段记录爆炸过程的光谱数据，结合爆发过程的电压时间曲线分析Al/Ni纳米复合膜的爆发机理，并与单一元素的纳米金属膜的爆发曲线及光谱数据进行对比分析，在单一元素纳米金属膜爆发机理的理论基础上完善纳米多层复合膜材料在强电激励下的爆发理论研究，为特殊超细纳米粉体金属间化合物材料的设计、制备及应用建立理论框架。

Al/Ni纳米复合膜是一类具有纳米级亚层结构的新型含能材料，它具有触发能量低、反应放热大和燃烧速率可控等优点，在室温焊接和MEMS点火起爆装置的小型化上，都具有广阔的应用前景。薄膜制备过程中，相邻周期的沉积间引入冷却工艺，保证镀膜机制备室温度不高于26 °C。通过靶材的交替溅射，制备了调制周期分别为40，55，70，90，120和180 nm的Al/Ni纳米复合膜，并对其厚度、截面形貌、电阻率、放热量、燃烧速率和物相变化进行了表征。在背散射电子成像下，可以观察到样品薄膜致密，截面层状结构明显，层厚均匀，没有发现明显的预混层。随着调制周期的下降，复合膜电阻率逐渐升高。本研究制备出的Al/Ni纳米复合膜放热量在1085~1198 J/g之间，当调制周期在40~120nm范围，燃烧速率的实测数据与E=122.1 kJ/mol时的Mann模型能够很好的拟合，相关系数达到0.9898。燃烧前后样品的XRD分析证明了复合膜燃烧过程发生了金属间化合反应。通过对国外规律性结论的重现和与Mann燃速解析模型的匹配，验证了所制备的Al/Ni纳米复合膜材料达到了国外同类产品的水平。采用微加工工艺制备了相同厚度的Cu和Al/Ni复合膜桥箔，研究发现在1306 V的低电压起爆实验中，复合膜的沉积能量为0.1205~ 0.1274 J，相对于Cu箔提高了近一倍。1900 V电压起爆时，Al/Ni膜沉积能量也比Cu箔提升了18 %~ 58%。表明Al/Ni纳米复合膜能降低爆炸箔起爆系统的起爆阈值，提高其冲击起爆的可靠性。本项目研究提出了反应性桥箔爆发经历了导体初始加热-Al层发生汽化扩散-金属间化合物AlNi生成并逐渐加热-本征爆炸-气态导体电离五个阶段，合金桥箔爆发经历了导体初始加热-本征爆炸-气态导体电离三个阶段的爆发机理，合理地解释了复合膜爆发电压分段现象及桥箔驱动能力与微观结构的关系。