Hybrid bimetallic-thermite reactive composites: ultrasonic powder consolidation, ignition characterization and application to soldering.

• Online Access: http://hdl.handle.net/2047/D20200302

Nanoheaters reactive composites have constituents in nano-scale in at least one dimension and when ignited can generate heat in calculated amounts through self-propagating exothermic reactions among the constituents. Due to their metastable nature, fabrication of nanoheaters requires a method that does not involve exposure to high temperature. Ultrasonic powder consolidation (UPC) is one such process in which powder particles are consolidated under the action of ultrasonic vibration at low to moderate temperature for a short duration of time, usually less than a few seconds. In this study, nano-thick flakes of aluminum and nickel prepared by a proprietary ball milling process and thermal plasma-synthesized nanoparticles of Fe₂O₃ and CuO were successfully consolidated by UPC into bimetallic Al-Ni nanoheaters, thermite Al- Fe₂O₃ and Al-CuO neanoheaters and new Al-Fe₂O₃-x(Al-Ni) and Al-CuO-x(Al-Ni) hybrid bimetallic-thermite nanoheaters. Full-density consolidation with metallurgical bonding through the Al nanoflakes was achieved for all nanoheaters at consolidation temperatures as low as 573 K in just 1 s.