Non-linear Electro-explosive Devices Based On Energetic Multilayer Films

Nonlinear electro-explosive devices possess excellent security and reliability, and play a key role among initiators and pyrotechnics. Energetic multilayer films (EMFs) consisting of alternating layers of the reactants is a new type of energetic materials. Among them, Al/CuO, Al/MoO3, and Al/Fe2O3 EMFs have attracted much more attention for their high reaction heat. This dissertation studied the preparation and characterization of Al/CuO, Al/MoO3, and Al/Fe2O3 EMFs. Next, this dissertation studied the novel nonlinear electro-explosive devices based on EMFs. The particular research contents and conclusions are as follows:(1) Al/CuO, AI/MoO3, and Al/Fe2O3 EMFs of micro and nano modulation periods were prepared by magnetron sputtering, respectively. The as-deposited EMFs were characterized by varied analytical techniques, including SEM, AFM, XRD, XPS, and DSC. In addition, its reaction paths and reaction kinetics were discussed. Results show that the films are smooth, and posess excellent layered structure. The Al films in EMFs are all tetragonal. The CuO films are composed of polycrystalline CuO and Cu2O. The MoO3 films are composed of amorphous MoO3, Mo2O5 and MoO2. The Fe2O3 films are composed of polycrystalline Fe2O3 and FeO. The EMFs have good stability and long-term preservation. Once initiated, the EMFs react rapidly, and the reaction products are mainly single crystalline metals and amorphous Al2O3.(2) The design, fabrication, and characterization of SCB-Al/CuO and SCB-Al/MoO3 are presented. The device consists of a semiconductor bridge (SCB) heating element, which has been selectively coated with Al/CuO or Al/MoO3 multilayer nanofilms to enhance reliability. Integrated negative temperature coefficient thermistor chip (NTC) provides protection against 1 A/1 W/5min and electrostatic discharge events. It is demonstrated that NTC has no distinctly influence on the electrical properties of SCB-Al/CuO and SCB-Al/MoO3.(3) The electrical explosion performance of SCB, SCB-Al/CuO, and SCB-Al/MoO3 is styudied under the condition of capacitance discharge.Results show that the critical ignition delay and critical ignition energy of SCB-Al/CuO and SCB-Al/MoO3 have no significant difference with SCB.The total energy and the total time of SCB-Al/CuO and SCB-AI/MoO3 have significant difference with SCB due to the impact of heat released by the reaction of EMFs. Compared with SCB, the input energy utilization rate of SCB-Al/CuO and SCB-Al/MoO3 are less, but the output energy efficiency, the plasma temperature, the flame height and the burning area of SCB-Al/CuO and SCB-Al/MoO3 are higher than SCB. When there is a gap of 1mm between the flims and the bridge, SCB-AI/MoO3 can ignite the free standing Al/Ni films reliably but the SCB can’t do this under the same condition.(4) Based on capacitive discharge and heat transfer theory, the electrical explosion model, EMFs temperature distribution model,and EMFs self-propagation model were established. Some analytical expressions of critical ignition delay and critical ignition voltage were obtained.Analysis of the temperature distribution and self-propagation of EMFs during its electrical explosion was given. The models explain the electro-explosive performance preferably, and provide theory and computing method for the design and optimization of energetic SCB(5) CuO is semiconductor. Through theoretical analysis, it is found that threshold of electrical stimulation exists for Schottky Barrier structured Al/CuO multilayer films, and the reasons can be related to the series surface contact Schottky junctions formed between individual Al and CuO films.The design, fabrication, and characterization of S-Al/CuO and S-Al/CuO/Cr are presented. S-Al/CuO possesses direct-current blocking and late time discharge characteristics when it is initiated with capacitor discharge unit. After electrical breakdown is realized, it possesses a positive feedback effect of increasing thermal power. After electrical breakdown is realized, the whole firing energy of S-Al/CuO/Cr is 40V when it is initiated with constant voltage. Once initiated by electrical stimulation, S-Al/CuO and S-Al/CuO/Cr explode, which releases not only Joule heat, but also chemical reaction heat between CuO and Al, resulting in more output energy.