Exhibition Keynote Lecture
Tuesday, April 29, 2014 11:00 AM in Room California
Ex-1 Driving Commercial Applications and Exploring Scientific Questions with Reactive Multilayer Foils
Timothy Weihs (Johns Hopkins University)
Reactive multilayer foils are sputter deposited to contain thousands of nanoscale layers that can mix and produce bursts of heat upon ignition, through a self-propagating, exothermic formation reaction. The laminate foils are sold as a local heat source called NanoFoil® and can replace furnaces and hotplates in conventional soldering operations. The very localized heating provided by the foils enables bonding of materials with large mismatches in contraction on cooling (metals and ceramics), as well as temperature-sensitive electronic components. Other applications include sealing packages, igniting reactions, and providing controlled time delays. Multiple applications will be described in this presentation. In addition, novel in situ experiments and modeling will be described that explore the rapid formation reactions within the reactive multilayer structures. The experiments utilize nanocalorimetry, dynamic transmission electron microscopy and synchrotron X-ray diffraction to identify changes in the sequence of phase transformations that appear during the rapid reactions, as a function of heating rate, chemistry, and concentration gradients. To help understand these transitions we draw on molecular dynamic simulations and analytical models.