Fabrication, characterization and applications of novel nanoheater structures

Nanoheaters are reactive nanostructures that can generate localized heat through controlled ignition. Besides the widely used nanofoil structure with multiple alternative Al–Ni layers, various new nanostructures have been fabricated in the last several years, including consolidated films, bimetallic nanoparticles and nanowires, and ball milled micro/nano powders. In this paper, we demonstrate the (1) Synthesis of Al–Ni bimetallic nanoparticles by a galvanic replacement reaction method using Al nanoparticle templates; (2) Fabrication of Al–Ni nanowire structures by a two-step process involving electrodeposition and thermal evaporation; (3) Fabrication of Al–Ni composites by a novel ultrasonic powder consolidation method, using Al and Ni nanoparticles as source materials and (4) Synthesis of nanostructured Al–Ni powders by low energy ball milling with microscale Al and Ni powders. The structure and compositions of the nanoheater structures have been characterized by scanning electron microscopy and transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The thermal characteristics of the samples were studied using differential scanning calorimetry. These novel nanoheater structures have great potential to be used in micro-joining, microelectronics assembly, and flexible electronics bonding.