Streak spectroscopy and velocimetry of electrically exploded Ni/Al laminates

Abstract

We present an experimental and theoretical study of electrically exploded nickel-aluminum (Ni/Al) laminates, lithographically patterned into bow-tie bridge regions, and encapsulated with parylene. The exothermic nature of Ni/Al reactions is well-known at typical self-heating rates of 103–106 K/s, but electrical heating allows the interrogation of phenomena at heating rates which are five to six orders of magnitude higher. The use of time-resolved streak camera emission spectroscopy revealed that Ni/Al laminates heated at these higher rates exhibited brighter emission during the first 150 ns of emission than samples composed of either Al or Ni alone, suggesting an exothermic effect which rapidly started and persisted for at least this length of time. We also measured the transduction of electrical energy into kinetic energy through velocity measurements of encapsulation layers ejected from the bridge region. An empirical model using experimental power curves and one empirical fitting parameter successfully predicted these velocities. This model agreed well with experiments from different Al and Ni samples using the same fitting parameter, but an apparent 1.2 J/mg of additional energy from the mixing of Ni and Al was necessary to accurately predict velocities from Ni/Al laminate samples. This energy quantity corresponded to a reference value for the enthalpy of mixing Ni and Al, and likely contributed to both brighter emission and higher than expected velocities observed.

Improved Exploding Properties of Al/Cu Multilayer Initiators

“…The results are in good agreement with data obtained in Ref. [22], the Al/Cu multilayers applied to the initiator demonstrates that the flyer velocity can be improved due to the effect of added reaction energy. However, the total reaction energy of Al/Cu multilayers is assumed to be 4.0 mJ which is much lower than the increased value.…”

“…In 2009, with the hope of adding the reaction heat to the traditional joule heat to increase the final velocity of EFIs, Morris et al investigated the electrical properties of initiator based on Al/Ni RMFs [21–23]. The experimental results indicated that the additional kinetic energy from Al/Ni RMFs contributed to the improved flyer velocity.…”

Analysis of Electric Explosion Performance of Ni/Cu Multilayer Foil

“…Multilayer film is used in mechanical, optical, electronic, energy, computer, sensor, magnetic recording, aerospace, and weapon applications [10][11][12][13][14]. Al/Ni multilayer film could induce self-propagating high-temperature synthesis reaction under low external energy excitation, thus releasing a large amount of heat instantly, moreover, the products are intermetallic compounds with good electrical and thermal conductivity [15,16]. In recent years, researchers have found that Al/Ni multilayer film has obvious application value in EFIs [17].…”

Energetic Al/Ni Superlattice as a Micro-Plasma Generator with Superb Performances

“…The reaction velocity and temperature of these foils are closely related to the composition and geometry [ 6 – 9 ]. They are potential for materials welding [ 10 – 12 ], explosive initiation [ 13 – 15 ], and biological neutralization [ 16 ].…”