← Back to Event List

Prof. Tim Weihs, Johns Hopkins University

Colloquium

Location

Physics : 401

Date & Time

September 24, 2014, 3:30 pm4:30 pm

Description

TITLE:  Driving Commercial Applications and Exploring Scientific Questions with Reactive Multilayer Foils 

ABSTRACT:   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

Location: Physics, Room 401