| AVS 63rd International Symposium & Exhibition | |
| Advanced Surface Engineering | Tuesday Sessions |
| Session SE-TuP |
| Session: | Advanced Surface Engineering Poster Session |
| Presenter: | Cathy Sobczak, Sandia National Laboratories |
| Authors: | D.P. Adams, Sandia National Laboratories R.V. Reeves, Lawrence Livermore National Laboratory M. Abere, Sandia National Laboratories C. Sobczak, Sandia National Laboratories |
| Correspondent: | Click to Email |
Reactive bimetallic multilayers are a form of energetic material that can be ignited at a point and undergo rapid, exothermic, self-propagating reactions. Providing a burst of heat, these materials continue to find use for different joining, battery and fusing applications. Much has been learned about the properties of these materials, yet little is known about the compositional limits of reactivity. In this presentation, we describe the propensity of sputter-deposited Al/Pt multilayers to undergo rapid, self-propagating formation reactions. Reactivity has been evaluated across a broad range of stoichiometry (nAl:mPt) and layer periodicity. Experiments demonstrate self-propagating reactions in ~1.6 micron-thick Al/Pt multilayers when the molar ratio of reactants is in the range 4Al:1Pt to 1Al:4Pt. This rather large compositional range is characterized by different reaction rates and behaviors. High-speed photography shows that equimolar Al/Pt multilayers undergo the most rapid reactions with wavefront speeds as large as 80 m/s. Al- and Pt-rich multilayers react at reduced rates with speeds as low as 1 m/s. A previously developed, analytical method by Mann et al. (J. Appl. Phys. 1997) is utilized to reveal additional details of reactions in the various multilayers. Models that account for the reactant layer thicknesses, composition, the adiabatic temperatures, the flame temperatures, and the measured heats of reaction are used to predict wavefront speeds that closely match measured values. These results are further analyzed to extract information regarding the mass transport characteristics of reactant species.
This work was supported by a Sandia Laboratory Directed Research and Development (LDRD) program. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under Contract DE-AC04-94AL85000.