Researchs On Electric Explosion Performances Of MEMS-based Micro-initiator

As a new type of electric explosive device,film bridge initiators exhibit excellent performances in terms of low initiation energy,high safety,good reliability and miniature size.In this dissertation,Al/Ni,like-PTFE/Al and B/Ti nano-multilayers were fabricated and investigated to integrate with the film bridge initiators to improve the energy conversion efficiency and energy output through combining the electrical energy with chemical energy.Furthermore,the Cu-Al/Ni,Cu-Al/PTFE,and Cu-B/Ti integrated film micro-initiators were prepared for exploding foil initiation system,and the TaN-B/Ti integrated film micro-igniter was fabricated for micro ignition system.The electric explosion performances of the integrated film bridges were investigated systematically through capacity discharge.The main results are as follows:1.Al/Ni nano-multilayers with uniform thickness and periodic multilayer structure were prepared and investigated.The exothermic reaction in Al/Ni nano-multilayers with a bilayer thickness of 500 nm(Al,300 nm;Ni,200 nm)can be initiated with onset reaction temperature as low as 220 ?,and the total reaction heat was about 887.4 J/g.An integrated film micro-initiator with “complete contact” structure was designed and prepared by integrating Al/Ni nano-multilayers with a Cu exploding foil,and two lands of copper pads were located at both sides to contact the Cu film bridge and the Al/Ni nano-multilayers.The Cu-Al/Ni integrated film micro-initiator exhibited improved performances with lower critical explosion energy,shorter burst time,larger plasma volume and higher explosion temperature compared with the Cu film bridge.The peak velocity of the flyer derived from the Cu-Al/Ni integrated film micro-initiator was 3053 m/s at a 2500 V discharge voltage,and the kinetic energy of the flyer increased by 19.5 %.2.In order to improve the energy conversion efficiency and energy output of the micro-initiator,like-PTFE/Al nano-multilayers were fabricated and investigated,which could provide high energy release and generate gas during the reaction.The periodic multilayer structure of the like-PTFE/Al nano-multilayers can be visible clearly,which consist of polycrystalline Al,amorphous like-PTFE,and inert layer Al-F compound in a metastable system.The as-deposited like-PTFE/Al nano-multilayers with a bilayer thickness of 125 nm(Al,50 nm;PTFE,75 nm)exhibited a significantly high energy output,the onset temperature and the heat of reaction were 410 °C and 3034 J/g,respectively.Based on these properties,an integrated film micro-initiator was designed and fabricated via integrating like-PTFE/Al nano-multilayers with a Cu exploding foil,which exhibited more violent explosion phenomenon with larger quantities of ejected product and higher plasma temperature in comparison with the Cu film bridge.The peak velocity of the flyer derived from the Cu-Al/PTFE integrated film micro-initiator was 3180 m/s at a 2500 V discharge voltage,and the kinetic energy of the flyers increased by 29.9 %.3.B/Ti nano-multilayers were fabricated and investigated for its high energy density and relatively simple preparation.The periodic multilayer structure of the B/Ti nanomultilayers can be seen clearly,which was composed of B layers(amorphous),Ti layers(polycrystalline),and intermixed reactants in a metastable system.The B/Ti nanomultilayers with a bilayer thickness of 100 nm(B,50 nm;Ti,50 nm)exhibited a significantly high heat release of 3722 J/g,with an onset reaction temperature of 449 °C.On the basis of these properties,an integrated micro-igniter was designed and prepared by the integration of B/Ti nano-multilayers with a Cu exploding foil.The critical explosion energy and burst time of the Cu-B/Ti integrated film micro-initiator rose slightly in comparison with the Cu film bridge.An extra violent explosion phenomenon with longer duration time and larger quantities of ejected product particles were detected on the Cu-B/Ti integrated film micro-initiator.The peak velocity of the flyer derived from the Cu-B/Ti integrated film micro-initiator was 2899 m/s at a 2500 V discharge voltage,and the kinetic energy of the flyer increased by 8 %.Furthermore,a TaN-B/Ti integrated film micro-igniter was realized by the integration of B/Ti nano-multilayers with a TaN film bridge.The TaN-B/Ti integrated film micro-initiator exhibited improved performances with lower critical explosion energy,shorter burst time,larger plasma volume and higher explosion temperature compared with the TaN film bridge.The energy conversion efficiency of the TaN-B/Ti integrated film micro-igniter increased by 60.4 % at a 40 V discharge voltage.