Investigation of Electrically Heated Exploding Foils in Reactive Al/Ni Multilayer

The mechanisms of metal phase transition process during electrical explosion are experimentally and theoretically investigated. Past experiments of investigation are single metal foil, such as gold, aluminum, and copper. The characteristics of aluminum-nickel (Al/Ni) multilayer foil were investigated, which means electrical behavior and energy output. The foil was fabricated by magnetron sputtering based on ceramic substrate, and lithographically patterned into bow-tie bridge regions. Scanning electron microscopy characterization revealed the layer structure of the Al/Ni multilayer. X-ray diffraction characterization was employed to ascertain the composition of Al/Ni. The probing of voltage-current waveforms reveals that Al/Ni multilayer foils exhibit high voltage, short burst time and high absorbing energy in electrically heated in comparison with copper or nickel alone. We also measured the energy output of foils through velocity measurements of encapsulation layers ejected from bridge region by Photonic Doppler velocimetry. We observed flyer velocities from Al/Ni multilayer foil in the 1.6-2.9km/s range, which is much higher than copper foil. Combined with the 1-D non-stationary acceleration model calculation, it is found that the chemical energy and increased electrical absorbing energy contributed to additional kinetic energy in the 40-80mJ range.